Three Phase Frequency Converter....pdf

THREE PHASE FREQUENCY CONVERTER

Group Members Qurat-Ul-Ain

UW-BSc-13-EE-016

Hafiz Muhammad Ashraf

UW-BSc-13-EE-030

Muhammad Jahanzaib

UW-BSc-13-EE-078

Zahid Ghafoor

UW-BSc-13-EE-090

Supervisor Mr. Haris Masood Department of Electrical Engineering WAH ENGINEERING COLLEGE WAH CANTT – PAKISTAN 2017

THREE PHASE FREQUENCY CONVERTER

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FINAL REPORT NUMBER OF MEMBERS

PROJECT ID

Three Phase Frequency Converter

TITLE

Electrical Department

M. Haris Masood

SUPERVISOR NAME

MEMBER NAME

REG. NO.

EMAIL ADDRESS

Quratulain Jamil

UW-BSc-13-EE-016

[email protected]

Hafiz Muhammad Ashraf

UW-BSc-13-EE-030

[email protected]

Muhmammad Jahanzaib

UW-BSc-13-EE-078

[email protected]

Zahid Ghafoor

UW-BSc-13-EE-090

[email protected]

CHECKLIST: Number of pages attached with this form

I/We have enclosed the soft-copy of this document along-with the codes and scripts created by ourselves

YES / NO

My/Our supervisor has attested the attached document

YES / NO

I/We confirm to state that this project is free from any type of plagiarism and misuse of copyrighted material

YES / NO

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STUDENT’S SIGNATURES

INTERNAL SUPERVISOR

_________________________________________________

__________________________ _________________________________________________

_________________________________________________

_________________________________________________

CHAIRPERSON-ELECTRICAL ENGINEERING

__________________________

____________________________ Note 1: This paper must be signed by your internal supervisor and external supervisor. Note 2: The hard copy of this report must be submitted to your supervisor and electrical engineering department, Wah Engineering

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DECLARATION

“No portion of the work referred to in the dissertation has been submitted in support of an Application for another degree or qualification of this or any other university/institute or other institution of learning”.

MEMBERS’ SIGNATURE

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Table of Contents

DECLARATION .......................................................................................................................................... 5 ACKNOWLEDGMENT............................................................................................................................. 14 ABSTRACT................................................................................................................................................ 15 Chapter 1 ..................................................................................................................................................... 16 Project Introduction .................................................................................................................................... 16 1.1 INTRODUCTION ................................................................................................................................ 16 1.2 PROJECT DESCRIPTION AND GOALS ........................................................................................... 17 1.2.1 RECTIFICATION ......................................................................................................................... 17 1.2.2 PULSE GENERATION THROUGH ARDUINO ......................................................................... 17 1.2.3 THREE PHASE INVERTER ........................................................................................................ 17 1.2.4 FLOW CHART .................................................................................................................................. 19 Chapter 2 ..................................................................................................................................................... 20 Literature review ......................................................................................................................................... 20 2.1 ROTARY CONVERTERS ................................................................................................................... 20 2.2 DRAWBACKS OF ROTARY CONVERTERS .................................................................................. 21 2.3 COST ISSUE ........................................................................................................................................ 21 2.4 SIZE ISSUE .......................................................................................................................................... 21 2.5 INCONVENIENCE .............................................................................................................................. 21 2.6 PROPOSED SOLUTION ..................................................................................................................... 21 2.6.1 EFFICIENT.................................................................................................................................... 22 2.6.2 COST EFFECTIVE ....................................................................................................................... 22 2.6.3 PORTABLE ................................................................................................................................... 22 Chapter 3 ..................................................................................................................................................... 23 Phase 1 Rectification................................................................................................................................... 23 Three phase frequency converter

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3.1 RECTIFICATION ................................................................................................................................ 23 3.1.1 WHEATSTONE BRIDGE ............................................................................................................ 23 3.1.2 THREE PHASE RECTIFICATION .............................................................................................. 24 Chapter 4 ..................................................................................................................................................... 26 Inverter Techniques .................................................................................................................................... 26 4.1 INVERTER ........................................................................................................................................... 26 4.2 PULSE WIDTH MODULATION CONTROL .................................................................................... 26 4.3 INVERTER TECHNIQUES ................................................................................................................. 26 4.3.1 SQUARE WAVE INVERTER ...................................................................................................... 27 4.3.2 MODIFIED SINE WAVE INVERTER ........................................................................................ 27 4.3.3 PURE SINE WAVE INVERTER .................................................................................................. 28 Chapter 5 ..................................................................................................................................................... 29 3-Phase Bridge Driver IC (IR2130) ............................................................................................................ 29 5.1 FEATURES .......................................................................................................................................... 29 5.1.1 DESCRIPTION.............................................................................................................................. 29 5.2 PIN CONFUGURATION ..................................................................................................................... 29 5.3 GATE DRIVE IC REQUIREMENTS .................................................................................................. 30 5.4 BOOTSTRAP OPERATION ................................................................................................................ 30 5.5 CONNECTIONS .................................................................................................................................. 31 5.6 ABSOLUTE MAXIMUM RANGES ................................................................................................... 31 5.7 INPUT/OUTPUT DIAGRAM .............................................................................................................. 32 5.8 WORKING PRINCIPLE ...................................................................................................................... 33 Chapter 6 ..................................................................................................................................................... 34 Single phase inverter circuit........................................................................................................................ 34 6.1 SINGLE PHASE INVERTER .............................................................................................................. 34 6.2 WORKING ........................................................................................................................................... 34 6.3 DRAWBACKS ..................................................................................................................................... 35 Three phase frequency converter

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Chapter 7 ..................................................................................................................................................... 36 Three Phase Frequency Converter .............................................................................................................. 36 7.1 INTRODUCTION ................................................................................................................................ 36 7.2 WORKING PRINCIPLE ...................................................................................................................... 36 7.2.1 180 DEGREE CONDUCTION MODE ......................................................................................... 37 7.2.2 OUTPUTS...................................................................................................................................... 38 7.2.3 120 DEGREE PHASE CONDUCTION ........................................................................................ 39 7.3 CIRCUIT DIAGRAM OF THREE PHASE INVERTER .................................................................... 40 Chapter 8 ..................................................................................................................................................... 42 Hardware Principles .................................................................................................................................... 42 8.1 RECTIFIER .......................................................................................................................................... 42 8.1.1 WORKING .................................................................................................................................... 42 8.2 INVERTER ........................................................................................................................................... 43 8.3 CIRCUIT DIAGRAM OF 6 PULSE INVERTER................................................................................ 43 8.3.1 COMPONENTS USED ................................................................................................................. 44 8.3.2 COMPONENT APPLICATIONS ................................................................................................. 45 8.4 IGBT (FGA25NI20ANTD) .................................................................................................................. 45 8.5 FEATURES OF IGBT (FGA25NI20ANTD) ....................................................................................... 47 8.6 MAXIMUM ABSOLUTE RATINGS .................................................................................................. 47 8.7 APPLICATION .................................................................................................................................... 48 8.7 OPTOCOUPLERS ................................................................................................................................ 48 8.7.1 FEATURES ................................................................................................................................... 48 8.7.2 PIN CONFIGURATION ............................................................................................................... 49 8.8 APPLICATIONS .................................................................................................................................. 49 Chapter 9 ..................................................................................................................................................... 50 Arduino and its specifications. .................................................................................................................... 50 9.1 ARDUINO ATmega2560 ..................................................................................................................... 50 Three phase frequency converter

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9.2 FEATURES OF ARDUINO ATMEGA2560 ....................................................................................... 50 9.3 ADVANTAGE ..................................................................................................................................... 51 9.4 ATMEGA2560 ..................................................................................................................................... 51 9.4.1 FEATURES ................................................................................................................................... 51 9.4.2 PIN CONFIGURATION ............................................................................................................... 52 9.4.3 USB TO SERIAL CONTROLLER ............................................................................................... 53 9.5 CODE PROGRAMMING AND SIMULATION ................................................................................. 53 9.6 APPLICATIONS .................................................................................................................................. 53 Chapter 10 ................................................................................................................................................... 55 (VFD) Variable frequency Drive ................................................................................................................ 55 10.1 VFD .................................................................................................................................................... 55 10.2 WORKING ......................................................................................................................................... 55 10.3 PARTS AND FUNCTION ................................................................................................................. 56 10.4 DESIGN .............................................................................................................................................. 58 10.4.1 EXAMPLE................................................................................................................................... 58 10.5 BENEFITS OF VFD ........................................................................................................................... 59 10.5.1 ENERGY SAVINGS ................................................................................................................... 59 10.5.2 CONTROL PERFORMANCES .................................................................................................. 59 10.5.3 INCREASED RELIABILITY ..................................................................................................... 59 10.5.4 SOFT STARTING ....................................................................................................................... 59 10.5.5 INCREASES MACHINE LIFE ................................................................................................... 59 10.6 APPLICATIONS ................................................................................................................................ 60 Chapter 11 ................................................................................................................................................... 61 Results and Discussions .............................................................................................................................. 61 11.1 METHOD FOR RESULT CALCULATION ..................................................................................... 61 11.2 OUTPUT WAVEFORMS .................................................................................................................. 61 11.2.1. CASE 1 (50 Hz) .......................................................................................................................... 61

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11.2.2 CASE 2 (100 Hz) ......................................................................................................................... 63 11.2.3 CASE 3 (150 Hz) ......................................................................................................................... 65 11.2.4 CASE 4(200 Hz) .......................................................................................................................... 67 11.2.5 CASE 5(250 Hz) .......................................................................................................................... 69 11.2.6 CASE 6(300 Hz) .......................................................................................................................... 70 11.2.7 CASE 7(350 Hz) .......................................................................................................................... 72 11.2.8 CASE 8 (400 Hz) ......................................................................................................................... 74 TABLE OF SPECIFICATIONS ................................................................................................................. 76 CONCLUSION ........................................................................................................................................... 78 FUTURE RECOMMENDATIONS ........................................................................................................... 78 APPENDIX ................................................................................................................................................. 79 REFERENCES ........................................................................................................................................... 85

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List of figures Figure 1.1: Rotary Converter ...................................................................................................................... 13 Figure 1.2 Block Diagram........................................................................................................................... 15 Figure 1.2.4: Flow Chart ............................................................................................................................. 16 Figure 3.1: Simple Rectifier Circuit ............................................................................................................ 20 Figure 3.1.1: Diode Bridge Rectifier .......................................................................................................... 21 Figure 4.3.1: Waveform of Square Wave Inverter ...................................................................................... 24 Figure 4.3.3: Pure sine wave inverter waveform ........................................................................................ 25 Figure 5.5: Lead Connection of IR2130 ..................................................................................................... 27 Figure 5.7: Input/Output timing diagram ................................................................................................... 29 Figure 6.1: Single Phase Bridge Inverter .................................................................................................... 31 Figure 7.2: Three phase inverter circuit ...................................................................................................... 34 Figure 7.2.2:Phase Voltages ....................................................................................................................... 34 Figure 7.2.3: LineVoltages ......................................................................................................................... 36 Figure 8.1: Three phase rectifier circuit ...................................................................................................... 38 Figure 8.2: 6 pulse circuitry ........................................................................................................................ 39 Figure 8.5: Symbol of IGBT (FGA25N120ANTD) ................................................................................... 43 Figure 9.1: Arduino ATmega 2560 ............................................................................................................. 46 Figure 9.4.2: Pin configuration ................................................................................................................... 49 Figure 10.2: General Diagram of VFD ....................................................................................................... 52 Figure 11.2.1 (a): Line voltages .................................................................................................................. 58 Figure 11.2.1 (b) :Phase voltages ................................................................................................................ 58 Figure 11.2.1 (c): Measured parameters ..................................................................................................... 59 Figure 11.2.2 (a): Line voltages .................................................................................................................. 60 Figure 11.2.2 (b) :Phase voltages ................................................................................................................ 60 Figure 11.2.2 (c): Measured parameters ..................................................................................................... 61

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Figure 11.2.3 (a): Line voltages .................................................................................................................. 62 Figure 11.2.3 (b) :Phase voltages ................................................................................................................ 62 Figure 11.2.4 (a): Line voltages .................................................................................................................. 63 Figure 11.2.4 (b) :Phase voltages ................................................................................................................ 64 Figure 11.2.4 (c): Measured parameters ..................................................................................................... 66 Figure 11.2.5 (a): Line voltages .................................................................................................................. 65 Figure 11.2.5 (b) :Phase voltages ................................................................................................................ 66 Figure 11.2.6 (a): Line voltages .................................................................................................................. 67 Figure 11.2.6 (b) :Phase voltages ................................................................................................................ 67 Figure 11.2.6 (c): Measured parameters ..................................................................................................... 68 Figure 11.2.7 (a): Line voltages .................................................................................................................. 69 Figure 11.2.7 (b) :Phase voltages ................................................................................................................ 69 Figure 11.2.8 (a): Line voltages .................................................................................................................. 70 Figure 11.2.8 (b) :Phase voltages ................................................................................................................ 71 Figure 11.2.8 (c): Measured parameters ..................................................................................................... 71

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List of tables Table 1 : Absolute Maximum ranges of IC IR2130 ................................................................................... 28 Table 2 : Switch states of three phase inverter............................................................................................ 33 Table 3 : Absolute ratings of IGBT ............................................................................................................ 43 Table 4: Configuration table ....................................................................................................................... 48

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ACKNOWLEDGMENT All grace to Almighty Allah who is the most beneficent and the most merciful, and who has given his men the instinct and power to think and create. Behind every work’s success there is an effort of a number of wonderful people who have always given their valuable advice or lent a helping hand. I sincerely appreciate the support and guidance of all those people who have been helping in making this project a success. We would like to thank department of Electrical Engineering of our prestigious college for allowing us to commence this project to success. We are extremely grateful to our supervisor sir Haris Masood whose help, critical advice and guidance helped us in all the time of research and doing this project successfully. We are deeply indebted to his whole hearted supervision and dedication in accomplishment of this project, Lastly, I place a deep sense of gratitude to my family members and my friends who have been constant source of inspiration during the preparation and completion of this project work.

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ABSTRACT The radar operates at a frequency of 400Hz but the frequency coming from main is 50Hz. So the project is devised to carter this problem. Secondly, the power supply units that are used to convert three- phase AC voltage from 50Hz to 400Hz are too big in size and are difficult to be carried to far-off places. The project is designed to carter this drawback and is made compact yet cost effective. The project includes an AC to DC (converter) circuit and then DC to AC (inverter) circuit by switching DC voltage using MOSFETs or IGBT, to achieve 400Hz. The work cycle begins as the 3 phase AC is converted to DC using rectifier circuit and then capacitor is used to smooth the voltage. This DC voltage is then converted into 400Hz by using a 3 phase inverter circuit. The output of 3 different phases is then supplied to the radar.

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Chapter 1 Project Introduction 1.1 INTRODUCTION This chapter provides a basic description of the project along with a brief description of radars, their working principles and their uses, more specifically the power supply units of the radars which provide the required ratings of 3 phase AC input to the radars. For a radar operation it requires an input of 3 phase AC voltage of 200 Volts 400 Hz rating. The desired rating of the frequency is obtained by power supply units that are attached to the radars. These power supply units work on rotatory converter principles to convert the frequency of the AC voltage coming from main grid (220 V 50 Hz).It consists of large generators and transformers which generates the voltage and frequency and then step down it to the desired level The main drawback of these power supply units is their size. These units are too big in size due to which they cannot be carried to far-off places as shown in figure 1.1, especially war zones, deserts and abandoned areas. Hence the desire for a portable frequency converter emerges.

Figure 1.1: Rotary converter

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1.2 PROJECT DESCRIPTION AND GOALS The main aim of the project is to design a frequency converter for 3 phase AC voltage .That consist of the following features 1. 2. 3. 4.

It converts 50Hz to 400Hz. Takes single phase 220V as input and gives an output of 3 phase 220V. The power rating is 2KVA It should be easy to carry to far-off places.

So that it can be used as an alternative to the main power supply units attached to radars, that are large and difficult in use, thus making it easier for them to be carried to different areas easily in the hour of need.

1.2.1 RECTIFICATION In the first phase of the project the incoming single phase AC voltage (220V 50Hz) from the grid is rectified using a simple bridge rectifier which is based on simple rectification techniques [4]. The AC 220V is converted into 310V DC.

1.2.2 PULSE GENERATION THROUGH ARDUINO Second phase of the project includes arduino, pulses are generated through arduino and is fed to the driver IC which controls the switching of IGBT’s.

1.2.3 THREE PHASE INVERTER Third phase involves design of a 3 phase inverter that converts single phase into three phase. This is done cascading three legs or 6 MOSFETs/IGBTs in series to obtain the following 3 phase output. The frequency of this output is set by changing the frequency of the MOSFETS/IGBTs. For this purpose arduino is used which controls the input to the driver IC hence controlling the switching of the MOSFETs/IGBTs [4].

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Figure 1.2: Block diagram Block diagram illustrates that:     

Firstly single phase AC supply of 220V is supplied as input to a rectifier. Secondly rectifier converts an input of single phase 220V 50Hz AC into 310V DC. Next this DC voltage is fed to a MOSFET/IGBT driver circuit that steps up frequency up using arduino or microcontroller, and desired frequency is achieved [10]. This DC voltage is fed to an inverter that converts the DC voltages in AC voltages of required frequency and ratings. And lastly, AC voltage is achieved having desired frequency.

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1.2.4 FLOW CHART Flow chart shows how each process has taken place from the start to the end of the project and how desirable frequency is attained by following the steps. Figure 1.2.4 shows the flow chart.

Figure 1.2.4: Flow chart Three phase frequency converter

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Chapter 2 Literature review 2.1 ROTARY CONVERTERS Rotary converters are electrical devices which act as a mechanical rectifier, inverter or frequency converter at a time. Rotary converters are used to convert AC current into DC current. Also used to convert DC voltages into DC voltages and are also used to convert frequency from one level to another level [3].So it can be called as a rectifier, an inverter and also as a frequency converter. They were commonly used to provide DC power for commercial, industrial and railway electrification from an AC power source. Frequency converters are a wide application of rotary converters and are still being used for this purpose. The figure 2.1 shows a typical frequency converter that is used for converting frequency to desired level.

Figure 2.1: Rotary inverter It consists of large generators and transformers which generates the voltage and frequency and then step down it to the desired level. Rotatory converter principle is to convert the frequency of the AC voltage coming from main grid (220 V 50 Hz) to DC voltage of desired frequency level.

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2.2 DRAWBACKS OF ROTARY CONVERTERS The main drawback of rotary converters is their size. These units are too big in size due to which they cannot be carried to far-off places as shown in figure 2.2, especially war zones, deserts and abandoned areas. Hence the desire for a portable frequency converter arises. Also another drawback of the rotary converters is that they were made obsolete by mercury arc rectifiers and later on by semiconductor rectifiers, which both had their own complications [3].

2.3 COST ISSUE The power supply units used for the radars right now are imported from foreign countries so it is highly expensive. The repairing cost of the machinery is also high. And the spare parts are not available and have to be imported if any fault occurs.

2.4 SIZE ISSUE Rotary converters are used for operating the radars or any other device working on 400Hz. And the main drawback of this machinery was that they worked on outdated techniques. Rotary converters are very large in size and needed to be imported from foreign countries, which is a difficult task and expensive.

2.5 INCONVENIENCE The power units used for operating radars are too big in size and inconvenient. They cannot be easily carried to far-off places in time of need. This issue was common when the radars where needed in areas other than the army units, and the power units because of their large size were inconvenient to be carried from one place to another.

2.6 PROPOSED SOLUTION By understanding the nature of problem, we have devised it to be  Efficient.  Cost effective.  Portable.

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2.6.1 EFFICIENT The solution for the above discussed problems are, that the operating machinery in the project is efficient and designed according to the latest and advanced technology and fabricated under latest techniques.

2.6.2 COST EFFECTIVE Also that the project is cost effective that is it doesn’t require and machinery to be imported from the foreign countries and all machinery is designed within country and has less manufacturing cost and so is cost effective.

2.6.3 PORTABLE Lastly the project is convenient and portable and can be easily carried to far of places, in the time of need. For this the project is made compact and can be easily carried to far-off places.

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Chapter 3 Phase 1 Rectification 3.1 RECTIFICATION Rectification is a process in which alternating current is converted into direct current (unidirectional) [5]. The rectification process is a simple process in which AC is converted into pulsating DC using diodes. The figure 3.1 shows the circuit diagram of a simple rectifier circuit and the output waveform is also shown.

Figure 3.1: Simple rectifier circuit

In the positive cycle, the diode is forward biased i.e. positive voltage occurs across its positive end that allows the current to pass through it. And in negative cycle, current is not allowed to pass as it is reverse biased.

3.1.1 WHEATSTONE BRIDGE Wheatstone bridge is a method used for full wave rectification. It construction consists of four diodes that convert AC into pulsating DC. In positive cycle, the diodes D1 and D2 are forward biased and thus completing the circuit by allowing current flow [1]. For the negative cycle the other two alternate diodes D3 and D4 are forward biased and allows the current to flow, and thus completing the circuit.

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Figure 3.1.1 shows a diode bridge rectifier.

Figure 3.1.1: Diode Bridge Rectifier

3.1.2 THREE PHASE RECTIFICATION In our project three phase rectification is used, as we are working on three phase frequency converter. This circuit in figure 3.1.2 (a) below is a result of cascading the simple diode rectification circuit for the three different phases.

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Figure 3.1.2 (a): Three-phase rectifier circuit

Three-phase diode rectification converts a three-phase AC voltage input into a DC voltage as the output. It is called three phase rectification as it converts Three phase input into three phase output [4]. The waveforms at output of three phase rectification are shown in figure 3.1.2 (b):

Figure 3.1.2 (b): Output of three-phase rectifier The output waveform across is shown in the green color. Due to three phase input, the ripples in the output waveform are almost negligible resulting in a TUF (Transient Usage Factor) higher than the simple diode or Wheatstone bridge rectifier. An input voltage of 220 V is given to the three phase rectifier circuit. The output voltage after the rectification process is 310 V three phase. Three phase frequency converter

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Chapter 4 Inverter Techniques 4.1 INVERTER Process of converting the DC voltage in AC is known as inversion and the circuit used for this purpose is known as Inverter. This conversion is important as it is easy to step up and step down the AC voltage and is used for transmission of current. Also that the loss of AC voltage is comparatively less as compared to that of DC. AC power is more conventional than high voltage DC systems. There are many techniques, for conversion of DC to AC. The inverters mostly operate on pulse width modulation technique and few other techniques, which describes that inverter is a nonlinear efficient system.

4.2 PULSE WIDTH MODULATION CONTROL In this method a fixed DC input voltage is given to an inverter and the output is a controlled AC voltage. This is done by adjusting the frequency of switching of the inverter components. The advantages of PWM control are: 1. No additional components are required with this method. 2. The lower order harmonics can be easily eliminated or minimized in this method along with output voltage control [16]. 3. Since higher order harmonics can be filtered easily, the filtering requirements for this method are highly minimized [5].

4.3 INVERTER TECHNIQUES In this section different inverter techniques are discussed that are frequently used. The commonly used inverter techniques are: 1. Square Wave Inverter. 2. Modified Sine Wave Inverter. 3. Pure Sine Wave Inverter.

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4.3.1 SQUARE WAVE INVERTER Square wave inverter is the simplest method for DC to AC conversion. This method is used for single phase DC to AC conversion. In this technique the output voltage is switched from low to high without the intermediate value of 0V. For keeping the output power equal to input, the amplitude of the output square wave is kept equal to the rms value of the sine wave. The figure 4.3.1 shows the output waveform of a square wave inverter [4].

Figure 4.3.1: Waveform of square wave inverter

4.3.2 MODIFIED SINE WAVE INVERTER The modified and upgraded form of square wave inverter is a modified sine wave inverter. This technique is used for three phase conversion of DC to AC. . In this technique the output is still a square wave approximation of the sine. But unlike square wave inverter it has three levels that is high, low and zero level. The harmonics in this case are still high [1]. Basically harmonics are the integral multiples of the fundamental frequency that occur due to sine wave approximation. The main issue that occurs due to harmonics is increase in current flow. For simple devices, this is the easiest and the most cost effective solution. For this we use 2 topologies 180 degree and 120 degree topology.

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4.3.3 PURE SINE WAVE INVERTER In this method of modulation, several pulses per half cycle are used and the pulse width is a sinusoidal function of the angular position of the pulse in a cycle. A triangular wave of high frequency Vc used as carrier wave, which is compared with a sinusoidal reference wave Vr of the desired frequency [6]. The switching instants and commutation of the modulated pulse are determined by the intersection of Vc and Vr waves [16]. The carrier wave Vc and reference wave Vr is given to a comparator. The comparator gives a high output if the magnitude is the sinusoidal wave is higher, otherwise the output of the comparator is low [6]. The comparator output is processed in a trigger pulse generator in such a way that the output voltage wave has a pulse width in agreement with the comparator pulse width. The figure 4.3.3 shows waveform of pure sine wave inverter

Figure 4.3.3: Pure sine wave inverter waveform

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Chapter 5 3-Phase Bridge Driver IC (IR2130) 5.1 FEATURES            

Bootstrap operation that is designed particularly for floating outputs, Fully operational to voltages above 600V Tolerant to negative transient voltage. Gate-drive supply ranges from 10 to 20V. For all channels there exists an Under-voltage lockout. All six drivers are shut down in case of over-current. Half-bridge drivers are independent. For all channels there occurs a matched propagation delay 2.5V logic compatible Outputs are out of phase with the inputs. Cross-conduction prevention logic LEAD-FREE driver IC’s are also available [17].

5.1.1 DESCRIPTION The IR2130 is a high voltage, high speed power MOSFET and IGBT driver with independent high and low side referenced output channels. Proprietary HVIC and latch immune CMOS technologies enable ruggedized monolithic construction. Logic inputs are compatible with standard CMOS or LSTTL outputs, down to 3.3V logic. The output drivers feature a high pulse current buffer stage designed for minimum driver cross-conduction [18]. Propagation delays are matched to simplify use in high frequency applications. The floating channel can be used to drive an N-channel power MOSFET or IGBT in the high side configuration which operates up to 600 volts.

5.2 PIN CONFUGURATION Pin configuration shows that an IR2130 consists of 28 leads. Each pin has its own independent functions. Figure 5.2 shows the lead connection of the driver IC [13].

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Figure 5.2: Lead connection of IR2130

5.3 GATE DRIVE IC REQUIREMENTS Gate drive IC’s normally used in motor drives, UPS and converters have a driving signal with following requirements:  It must have an amplitude of 10-15V.  For rapid charge and discharge of the gate capacitance, the driver IC must have low source resistance [7].  Floating outputs are required so that high side switches can be driven.

5.4 BOOTSTRAP OPERATION For supplying power for floating outputs of the driver IC, three bootstrap capacitors are required. The value of these bootstrap capacitors, are the function of gate charge requirements of the power switch. And also depends upon the maximum time power switch is on. Bootstrap capacitors are also called the Decoupling Capacitors.

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5.5 CONNECTIONS The typical connections of the driver IC IR2130 are shown in the figure 5.3

Figure 5.5: Connection diagram of IC 1R2130

5.6 ABSOLUTE MAXIMUM RANGES Absolute Maximum Ratings describe the maximum limits sustained beyond which damage to the device may occur as shown in figure 5.6 [17]. The absolute current and voltages ranges for both maximum and minimum are in figure 5.6

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Figure 5.6: Absolute maximum ranges of IC IR2130

5.7 INPUT/OUTPUT DIAGRAM The input and output timing diagram of IR2130 is shown in figure 5.5

Figure 5.7: Input/ Output timing diagram

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5.8 WORKING PRINCIPLE IR2130 is a high voltage power MOSFET and IGBT driver IC. The reference design is a fullfunction unit operating out of 220VAC input. The output drivers offer minimum driver crossconduction by using high pulse current buffer specially designed for this function. To simplify the use at higher frequencies, propagation delays are matched. To drive the MOSFETs or IGBTs of N-channel, floating channels are used in the high side configuration which operates up to a voltage of 600V [4]. The IC IR2130 helps in fast and efficient switching. Since the IGBT is concerned with rapid turning on and turning off, so the IR2130 helps in driving and allowing the switching function of IGBT to occur smoothly.

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Chapter 6 Single phase inverter circuit 6.1 SINGLE PHASE INVERTER A single phase voltage source inverter is shown in figure 6.1 (a). It consists of four choppers. The switches consist of IGBT’s or MOSFET’s. Switch Q1 AND Q2 are turned on simultaneously, the input voltage Vs appears on load. And if switches Q3 and Q4 are turned on simultaneously, the voltage across the load is reversed. It is termed as –Vs [4].

Figure 6.1: Single phase bridge inverter

6.2 WORKING A single phase inverter or a single leg square wave inverter works on most simple principle of inversion. The HO pin of the driver IC IR2130 is set high which in turn switches the upper MOSFET/IGBT on connecting the circuit with the load and the current starts flowing in the downwards direction. The direction voltage difference is also shown in figure 6.1. After half time period T, the HO pin is set low and the LO is set high. This switches the other MOSFET/IGBT on [5]. Now the direction of current flow and potential difference is opposite to the previous circuit connections. Hence a square wave of time period T is shown as output on the load. Three phase frequency converter

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6.3 DRAWBACKS The circuit has many advantages with this one main drawback that the single phase inverter or the single leg square wave inverter can only be used for driving a single load. Moreover, the load connected with single phase inverter can only be resistive load. And so the inverter circuit is unable to drive a single phase motor [4]. Also it is impossible for the inverter circuit to drive any other inductive load for that matter.

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Chapter 7 Three Phase Frequency Converter 7.1 INTRODUCTION A three phase inverter is a device that converts a single phase DC voltage into a three phase AC voltage. The circuit topology for a three phase inverter is cascading three legs of single phase inverters in series with the phase difference of 120 degrees between them [12]. A three phase output can be obtained by a configuration of six transistors and six diodes. Two type of control signals can be applied to transistors 180 degree conduction and 120 degree condition [4].

7.2 WORKING PRINCIPLE There are six MOSFETs/IGBTs used in the circuit as switches. The three phase output is obtained by controlling the switching pattern of these switches. As shown in figure 7.2. The basic catch in this circuit is that the switches are driven in such a way that the switches of same column are not turned on at the same time [1]. The output signals of single phase inverters must have a phase shift of 120 degrees between each other so as to obtain a three phase AC signal when combined. To achieve the above mentioned goal, there are two types of conduction modes in a three phase 6 leg inverter circuit. 1. 180 degree conduction 2. 120 degree conduction In both the cases all the MOSFETs are turned on after the interval of 60 degrees but there on interval is different

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Figure 7.2: Three-phase inverter circuit

7.2.1 180 DEGREE CONDUCTION MODE Each transistor conducts for 180 degree. Three transistors in the circuit remain on at any instant of time. The switches cannot be switched on concurrently in any leg of the inverter circuit. This can cause short circuit across the dc link of the voltage supply in the circuit. In this mode of operation three out of six switches are conducting at one time. Each switch (MOSFET/IGBT) is operated with an angle delay of 60 degree [4]. Using this method of conduction we can easily obtain a pure sine wave from the output by using simple filters, this is the reason why this mode of operation is called “A Quasi-Square Wave Mode. The table in figure 7.2.1 shows the states of the switches being operated

Figure 7.2.1: Switch states of three phase inverter

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The MOSFETs are kept on for a time of 180 degree and they are turned on after 60 degrees. So the output we get are: 1. Phase voltage. 2. Line to line voltage.

7.2.2 OUTPUTS The output of 180 degree conduction mode operating switches are shown in figure 7.2.2

Figure 7.2.2 (a): Phase voltage

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: Figure 7.2.2 (b): Line voltage

7.2.3 120 DEGREE PHASE CONDUCTION In this case each MOSFET is turned on after 60 degree but it is kept on for 120 degrees. The output is as follows [4].

1. Phase voltage 2. Line to line voltage

The output of 120 degree conduction mode operating switches are shown in figure 7.2.3 (a) and (b).

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Figure 7.2.3 (a): Phase voltage

Figure 7.2.3 (b): Line voltage

7.3 CIRCUIT DIAGRAM OF THREE PHASE INVERTER The circuit diagram as showed in figure 7.3 is a 3D view of three phase 6 pulse inverter circuit.

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Figure 7.3: 3D view of three phase 6 pulse inverter circuit

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Chapter 8 Hardware Principles 8.1 RECTIFIER As the goal in the rectification mode is to convert the three phase AC voltage signal coming from the main power grid into DC voltage. The rectification technique chosen to achieve this goal from the different rectification techniques is the three phase rectification technique [14]. The circuit diagram of a three phase rectifier, drawn and simulated in ISIS is shown in the figure 8.1

Figure 8.1: Three-phase rectifier circuit

8.1.1 WORKING The main supply of three phase AC (220V 50Hz) is connected to the input of the rectifier circuit. It converts this three phase AC voltage of 220 V rating into a DC voltage of magnitude 310 volts. The output waveform observed by the oscilloscope is given in the figure below

Figure 8.1.1: Output waveform of three phase rectification Three phase frequency converter

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8.2 INVERTER The purpose of inverter in our project is to convert the DC 220 volts into a three phase AC voltage signal with the frequency of 400 Hz. The inverter topology used in the project is three phase square wave inverter or 6 pulse inverter circuit as shown in figure 8.2

Figure 8.2: 6 pulse inverter circuitry

8.3 CIRCUIT DIAGRAM OF 6 PULSE INVERTER Figure 8.3 shows the circuit diagram of a three phase 6 pulse inverter circuit. There are six MOSFETs/IGBTs used in the circuit as switches. The three phase output is obtained by controlling the switching pattern of these switches [4]. The basic catch in this circuit is that the switches are driven in such a way that the switches of same column are not turned on at the same time.

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Figure 8.3: 6 Pulse Inverter circuit

8.3.1 COMPONENTS USED The three phase inverter contains following main components 1. 2. 3. 4.

MOSFETs/IGBTs as switches. IR2130 Driver IC. Arduino. Optocoupler (6N137)

IGBTs have been the preferred device under these conditions: 1. 2. 3. 4.

Duty cycle is small. Frequency is low up to 20kHz. Load variations are narrow. Voltage applications are high up to 1000V. Three phase frequency converter

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5. At high junction temperature, the operation is allowed (>100°C). 6. The output power is always less than 5KW [17]. Typical IGBT applications include: 1. Motor control: Frequency <20kHz, short circuit/in-rush limit protection. 2. Uninterruptible power supply (UPS): Constant load, typically low frequency. 3. Welding: High average current, low frequency (<50kHz), ZVS circuitry. 4. Low-power lighting: Low frequency (<100kHz) [17].

8.3.2 COMPONENT APPLICATIONS Circuit consists of components performing functions given as follows: o The IGBTs are controlled by the driver IC IR2130 which is connected to the Arduino. o The Driver IC IR2130 is used to drive the IGBT’s and control their operation in the circuit [1]. o The 180 degree mode of conduction is used. o The Arduino is used to for producing desired frequency of 400Hz. o The Arduino consists of a code that is created to obtain desired frequency of 400 Hz. o Optocouplers (6N137) are used to isolate the circuitry of three phase 6 pulse inverter and driver circuit (IR2130) [4]. o 12V battery is used to supply dc voltages to the optocoupler and driver IC 1R2130.

8.4 IGBT (FGA25NI20ANTD) IGBT are fast switching devices. They have both the characteristics of BJT’s and MOSFET’s. The IGBT’s like MOSFET’s have relatively high input impedance. And like BJT’s have low onstate losses, in case of conduction. The symbol and circuit of IGBT is shown in figure 3.4(a).The three terminals are emitter, collector and gate. Like gate drain and source in case of MOSFET’s [18].

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Figure 8.4 (a): Symbol and circuit of IGBT The typical transfer characteristics and input characteristics of IGBT are given below in figure 8.4(b).

Figure 8.4 (b): Transfer characteristics and input characteristics of IGBT

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8.5 FEATURES OF IGBT (FGA25NI20ANTD) The IGBT used in the project is (FGA25NI20ANTD). The reason to use this IGBT among many IGBT’s is:     

NPT IGBT deals with superior conduction properties. It has better switching performance. It has high avalanche ruggedness and has stress-free parallel operation. The IGBT is appropriate for the resonant applications. It offers soft switching applications [18].

The figure 3.5 shows the symbol of the IGBT used

Figure 8.5: Symbol of the IGBT (FGA25NI20ANTD)

8.6 MAXIMUM ABSOLUTE RATINGS Absolute Maximum Ratings describe the maximum limits sustained beyond which damage to the device may occur as shown in figure 8.6

Figure 8.6: Absolute ratings of IGBT

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8.7 APPLICATION    

The IGBT is best for the resonant or soft switching applications such as induction heating, microwave oven. It has applications in AC variable frequency drives. It can be used for fast switching in three phase inverter circuits. It has wide applications in both DC and AC motor drives [4].

8.7 OPTOCOUPLERS The name indicates that this device is used to couple isolated circuits. It is made of light sensing components. It is used to interconnect two isolated circuits by optical interfacing, using light. The optocoupler used in the project is 6N137 as shown in figure and is used to couple the isolated circuits of 6 pulse inverter and arduino [4].

Figure 8.7: Optocoupler

8.7.1 FEATURES      

It has very high speed. The working voltages are double up to -480V. It has logic gate output. Output is strobable because of very high speed photo detector. It has an open collector. Temperature ranges between -40°C to +85.

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8.7.2 PIN CONFIGURATION The figure 8.7.2 shows the pin configuration of optocoupler 6N137. It consists of total of 6 pins. One ground, one source and 4 more pins performing specific functions.

Figure 8.7.2: Pin Configuration

8.8 APPLICATIONS     



It has wide applications in line receiving and line transmission process. It has applications in data multiplexing. It is used in power supply switching applications. It has wide applications in replacement of pulse transformer. It has applications in eliminating ground loop problems. It helps in peripheral interfacing in computers [5].

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Chapter 9 Arduino and its specifications. 9.1 ARDUINO ATmega2560 The microcontroller board is based on ATmega2560. The arduino ATmega2560 has 54 input and output pins, out of which 14 can be used as PWM. 16 pins are analog input pins. It has four hardware serial ports. It has everything that needs to support the microcontroller. It only needs a PC with a USB cable, and also can be powered by an AC to DC adapter. A battery can also be needed to get it started [16]. Figure 9.1 shows an arduino ATmega 2560.

Figure 9.1: Arduio ATmega2560

9.2 FEATURES OF ARDUINO ATMEGA2560     

It compromises microcontroller ATmega2560 Operating Voltages are 5V. Recommended input Voltage are between 7-12V. Input Voltage limits between 6-20V. It consists of 54 pins. Three phase frequency converter

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    

It has 16 analog pins. DC Current per I/O Pin is 40 mA DC Current is 50 mA for 3.3V Pin. Flash Memory is 256 KB out of which 8 KB is used by the boot loader 16 MHz is the clock speed [16].

9.3 ADVANTAGE It comprises of everything required to support the microcontroller. Power it or connect it to a computer with a USB cable with a AC-to-DC adapter or with the help of a battery to start it. You can tamper with the arduino. ATmega2560 without worrying of doing something erroneous, worst case scenario the chip can be replaced cheaply and be started over again.

9.4 ATMEGA2560 The microcontroller is made using Atmel’s high density and non-volatile memory equipment. The Atmel ATmega2560 is a potent microcontroller that is highly flexible and cost effective. It has solution to many installed control applications. It does not use the FTDI USB-to-serial driver chip that makes the Mega2560 differs from all preceding boards. It features the Atmega8U2 programmed as a USB-to-serial converter. [14]. It is the main controller. The code, that we write for the Arduino is executed by the controller ATmega2560 and is connected directly to the I/O pins. The USB to serial controller loads the code into the ATmega2560 so that it can be programmed directly via the ICSP pins.

9.4.1 FEATURES The features include pin count, flash, general purpose input and output lines. Also includes 8-bit and 16-bit counters. The figure 9.3.1 shows various features of microcontroller ATmega2560, that makes it a better and preferred microcontroller [16].

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Figure 9.3.1: Configuration Summary

9.4.2 PIN CONFIGURATION The pin configuration of the arduino ATmega2560 is shown in figure 9.4.2. It consists of 54 pins, each performing different functions. It has 14 pins that can be used as PWM. 16 pins are analog input pins. It has four hardware serial ports. And has four power pins.

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Figure 9.4.2: Pin configuration

9.4.3 USB TO SERIAL CONTROLLER The USB controller device is employed with the ATMEGA8U2-MU. It is used to load the programmed code into the ATmega2560.

9.5 CODE PROGRAMMING AND SIMULATION The code is programmed on software specially designed for the type of arduino being used, and then the code is simulated to run and is loaded in the ATmega2560 through boot loader.

9.6 APPLICATIONS Arduino has been the preferred device under these conditions: 

It is not very expensive to use. Three phase frequency converter

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  

  

It has an open source hardware feature which makes it easy for the users to change the features, by using the available one as the reference source. The Arduino software is well-suited with all the different types of operating systems like Windows, and Macintosh etc [16]. It also comes with open source software feature which enables experienced software developers to use the Arduino code to merge with the existing programming language libraries and can be extended and modified. It is easy to be used by beginners. Arduino can develop projects that can easily stand alone. For example projects that consist of direct connectionS with the software that is loaded in the PC. It can be easily connected with the CPU of the computer, by using serial communication with help of USB, as it has the provision of built in power and reset circuitry.

So this is the reason why arduino is preferred over the microcontrollers in the project.

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Chapter 10 (VFD) Variable frequency Drive 10.1 VFD A variable-frequency drive (VFD) also called an adjustable frequency drive. VFD has applications in small industries for e.g. pumps and in large industries of mines and mills. VFD is a power electronics device that is a better compensation to all devices being used in the past. It is cost effective and has improved technology and performance in the field of electronics, and control systems [15].

10.2 WORKING The VFD is a power electronics device consisting of three distinctive sub-parts: 

A rectifier circuit.



A DC link.



An inverter circuit.

The figure shows a variable frequency drive general diagram that includes a rectifier part, a smoothing part and an inverter part. All these parts sum up to make a VFD. The rectifier, DC link and inverter all have their functions that make this power electronics device to work efficiently. All these parts can be distinctively shown in the general diagram of VFD [15].

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Figure 10.2: General diagram of VFD:

10.3 PARTS AND FUNCTION Variable frequency drive has the following function. a) Converter Converter is used to change the AC power supply to the DC power. b) Smoothing circuit it smoothens the pulsations in the DC power. c) Inverter Inverter is used to change the DC power to the AC power with varying frequency. d) Control circuit Control Circuit is used to primarily regulate the inverter part [15]. The converter consists of six diodes that allow unidirectional current Diodes are used for this purpose. These diodes allow the current to flow or stop current flow depending on the voltage direction. Converter circuit is shown in figure 10.3 (a).

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Figure 10.3 (a): Converter circuit A smoothing out capacity is actually used for the load. The smoothing circuit creates the DC voltage E2 with little pulsation from the rectified DC voltage E1 using a smoothing capacitor [15]. So capacitors are used to smooth out the DC voltages resulted from rectification as shown in figure 10.3 (b).

Figure 10.3 (b): Smoothing capacitors An inverter is a device that is used to create the AC from the DC power supply. Inverter consists of four switches, S1 to S4, that are connected to the DC power supply, S1 and S4 and also S2 and S4 are respectively paired and the pairs are alternatively turned ON and OFF so to obtain AC voltages. The AC flows as shown in figure 10.3 (c).

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Figure 10.3 (c): Inverter circuit The control unit controls the whole operation of the variable frequency drive; it monitors and controls the rectifier, the intermediate circuit i.e. the smoothing circuit and the inverter to deliver the correct output in response to an external control signal.

10.4 DESIGN To make a VFD an additional keypad and a LCD has been used. There is a switch button when it is turned on the circuit stops working. The required frequency is entered via keypad and is displayed on the LCD. The value of frequency is then fed to the controller which changes the switching frequency of transistor according to our desired frequency. For the controller we set the frequency of 400Hz as reference and all of the other frequencies were first compared with the values of 400Hz then we got the desired switching time for the transistor, Resulting in our required output frequency [15].

10.4.1 EXAMPLE Let, the time for 400Hz was 2303 milliseconds. So we multiplied 2303 with 400 and then divided it with the required frequency entered via keypad e.g. the time for 50Hz is 19708 milliseconds for Arduino controller. So we divided the product of 400 and 2303 with 50 it result it approx. 19708 millisecond. Hence through this way we achieved our task and made the VFD.

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10.5 BENEFITS OF VFD There are many benefits of VFD. Two important functions are mentioned as: 

Energy savings.



Control performances



Increased reliability.



Soft starting.

10.5.1 ENERGY SAVINGS When operated at variable speed with help of VFD, can be used to save energy and is very reliable when comes to constant-speed motor load applications that are delivered direct from AC power line. This type of energy saving and cost saving is linked with pumps and centrifugal machines. Such energy cost savings are especially prominent in variable-torque centrifugal fan and pump applications. And on these applications the torque and power P vary with square and cubes of speed. This innovation gives reduction in the power and causes energy savings as compared to constant-speed operation that gives fairly less reduction in power.

10.5.2 CONTROL PERFORMANCES VFD’s have brought quality improvements in the field of industrial and commercial developments like acceleration, speed, temperature and pressure flow. A motor can also be made to run in order to minimize electrical and mechanical stresses, and this is achieved by VFDs.

10.5.3 INCREASED RELIABILITY Traditional mechanical approaches are less reliable than speed motor-drive systems such as using valves, gears, turbines to control speed and flow. They are really reliable as have no moving parts like that of mechanical control system.

10.5.4 SOFT STARTING VFD’s are used for starting large motors, and so the disadvantages linked to heavy starting currents is reduced. This decreases the chances of damage caused due to insulation and winding. It also offers prolonged motor life.

10.5.5 INCREASES MACHINE LIFE Due to optimum voltage and frequency control it offers better protection and increases the machine life. And so less maintenance is required.

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10.6 APPLICATIONS 

  

VFD has applications in industrial complex that deals with the induction motors that work on the variable load. These motors have power ratings ranging between a few kilo and megawatts. VFD has applications in railway or traction systems as heavy load machines are used in railways. It has applications in the pumps, lifts and escalators. It also has applications in the refrigerators, air conditioners and economizers [15].

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Chapter 11 Results and Discussions 11.1 METHOD FOR RESULT CALCULATION The project’s main goal is to convert conventional frequency of 50 Hz into desirable frequency of 400 Hz, as many machines and devices operate on this frequency. For calculation of results a digital oscilloscope is used. The digital oscilloscope shows the desired waveforms of line to line and line to neutral voltages of a three-phase 6 pulse inverter circuit. Frequency and other parameters like time period, rise time, fall time and RMS voltages are also determined.

11.2 OUTPUT WAVEFORMS Digital Oscilloscope is used to observe the waveforms of 6 pulse three-phase inverter circuit. The line voltages and phase voltages are observed using the oscilloscope [4]. The waveforms are observed in 180 degree conduction mode, and these waveforms are observed as line to line voltages and line to phase voltages. The voltage waveforms show how the frequency converter obtains desired frequency using 6 pulse inverter circuit. Also the frequency can be calculated using formula. The waveforms are observed at different frequencies that are fed to the arduino through keypad and displayed on the LCD. Frequencies like 50, 100, 150, 200, 250, 300, 350 and 400Hz are observed.

11.2.1. CASE 1 (50 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 49.26 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f Input=50Hz Full time=1/50= 0.02sec. Conversion in micro second: 0.02*1000*1000= 20,000 µs. Output= 49.26Hz Full time=1/49.26=0.0203 Conversion in micro second: 0.0203*1000*1000= 20,300 µs. Three phase frequency converter

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Now the difference between input full time and output full time is due to the delay added by the arduino. Figure 11.2.1 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

Figure 11.2.1 (a): Line voltages

Figure 11.2.1 (b): Phase voltages Three phase frequency converter

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Figure 11.2.1 (c): Measured Parameters

11.2.2 CASE 2 (100 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 97.1477 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/100= 0.01sec Conversion in micro second: 0.01*106 = 10,000µs. Output=97.1477 Hz Full time=1/97.1477=0.01029µs Conversion in micro second: 0.01029*1000*1000= 10,293 µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.2 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

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Figure 11.2.2 (a): Line voltages

Figure 11.2.2 (b): Phase Voltages

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Figure 11.2.2 (c): Measured Parameters

11.2.3 CASE 3 (150 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 97.1477 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/150= 6.6×10-3 µs. Conversion in micro second: 6.6×10-3 *106 = 6666µs. Output=143.95 Hz Full time=1/143.95=6946µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.3 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

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Figure 11.2.3 (a): Line voltages

Figure 11.2.3 (b) Phase Voltages

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11.2.4 CASE 4(200 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 189.65 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/200= 0.005µs. Conversion in micro second: 0.005 *106 = 5000µs. Output=189.65Hz Full time=1/189.65=5272µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.4 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

Figure 11.2.4 (a): Line voltages

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Figure 11.2.4 (b): Phase Voltages

Figure 11.2.4 (c): Measured Parameters

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11.2.5 CASE 5(250 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 234.44 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/250= 4×10-3 µs. Conversion in micro second: 4×10-3 *106 = 4000µs. Output=234.44 Hz Full time=1/234.44=4265µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.5 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

Figure 11.2.5 (a): Line voltages

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Figure 11.2.5 (b): Phase voltages

11.2.6 CASE 6(300 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 278.07 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/300= 3.333×10-3 µs. Conversion in micro second: 3.333×10-3 *106 = 3333µs. Output=278.07 Hz Full time=1/278.07 = 3596µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.6 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

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Figure 11.2.6 (a): Line voltages

Figure 11.2.6 (b): Phase Voltages

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Figure 11.2.6 (c): Measured Parameters

11.2.7 CASE 7(350 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 320.28 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/350= 2.857×10-3 µs. Conversion in micro second: 2.857×10-3 *106 = 2857µs. Output=320.28 Hz Full time=1/320.28=3122µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.7 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

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Figure 11.2.7 (a): Line voltages

Figure 11.2.7 (b): Phase voltages

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11.2.8 CASE 8 (400 Hz) The desired frequency is fed to the arduino through the keypad feature and the oscilloscope displays the required frequency that is converted with help of 6 pulse driver circuitry and VFD together. In case 1, the desired frequency is50 Hz and the oscilloscope shows the required line voltage waveform and measures parameters for e.g. 362.32 Hz. Formula can be used to calculate the time period of the desired frequency by general formula: T=1/f T=1/400= 2.5×10-3 µs. Conversion in micro second: 2.5×10-3 *106 = 2500µs. Output=362.32 Hz Full time=1/362.32=2759µs. Now the difference between input full time and output full time is due to the delay added by the arduino.. Figure 11.2.8 (a) and (b) show the line voltages and phase voltages respectively, while (c) shows the measured parameters, with help of a digital oscilloscope.

Figure 11.2.8 (a): Line voltages

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Figure 11.2.8 (b): Phase Voltages

Figure 11.2.8 (c): Measured Parameters

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TABLE OF SPECIFICATIONS Ratings Sr no

Component

Description

Name

Voltages

Current

(V)

(A)

500V

10A

600V

5-6A

35V

650mA

10V

1000mA

16V

550mA

16V

410mA

400V

115mA

16V

77mA

50V

30A

1000V

30A

Resistor Type Carbon Film 1

Power, are pull up or pull Resistor (1K)

down resistor with microcontrollers. Resistor Type Carbon Film,

2

Resistor (16K)

used for current limiting. General purpose, used for

3

Capacitor (470µF)

filtering or smoothing voltages. General purpose, used for

4

Capacitor (1000µF)

filtering or smoothing. General purpose, used for

5

Capacitor (1200µF)

filtering or smoothing. General purpose, used for

6

Capacitor (220µF)

filtering or smoothing. General purpose, used for

7

Capacitor (100µF)

filtering or smoothing. Bootstrap capacitors, for

8

Capacitor (47µF)

maintaining voltages. General purpose rectifiers,

9

Diode (IN4001)

high surge current capability. General purpose rectifiers,

10

Diode (IN4007)

high surge current capability.

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3-Phase bridge driver IC, 11

IC IR2130

used to drive IGBT’s.

600V

420mA

1200V

150A

5V

5mA

35V

1.5A

6-20V

20-50mA

5V

5mA

24V DC

20mA

IGBT used for fast switching 12

FGA25N120ANTD

in three-phase circuits. Opto-couplers, used for

13

6N137

isolation. Voltage regulator, regulates

14

IC 7805

voltages up to 5V

15

Arduino ATmega

Arduino used for switching

2560

operation for IGBT’s

16x2 LCD

To display the desired

16

frequency 17

Membrane 3×4 matrix

Used to enter desired

keypad

frequency

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CONCLUSION This project was chosen to solve the problem of rotary converters, are used to convert frequency for radars, induction motors and in aircrafts. The main goal of the project was to design and fabricate a frequency converter that could convert frequency from 50 Hz to 400 Hz and is feasible, cost effective and most importantly concise and compact so that it can be easily carried to places of need. As the rotary converters are of very large size the repair, maintenance and transport of it was a major issue. The frequency converter in the project was designed to achieve frequency of 400 Hz AC three-phase. As for the milestones achieved at the end of the project, not only all the goals set in the start were achieved successfully but some additional tasks were also performed and tested successfully. The tasks were the design and fabrication of a VFD along with an LCD and keypad were added. As for the learning process, a lot was learnt during the course of the project. The project helped have a clearer concept of some major phenomenon in the field of electronics. It also helped in building a more practical approach and the problems relating to implementations of different circuit elements and topologies like transistor switching, DC-DC converters, gate drivers, Microcontrollers and high power MOSFETs, and frequency drives. Lastly, the project helped us in developing skills on working on our own and in establishing technical skills in field of engineering and technology.

FUTURE RECOMMENDATIONS The Project has a tendency to be upgraded in near future by integrating it with any Renewable energy resources i.e. Solar, Wind etc. Moreover, portability of project can also be improved and more work can also be done to make it a more marketable and standalone product in foreseeable future.

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APPENDIX #include LiquidCrystal lcd(23, 25, 27, 29, 31, 33); const int DEAD_TIME = 1; int count1 = 0; const int DRIVER_PIN1 = 5; const int DRIVER_PIN4 = 6; const int DRIVER_PIN2 = 7; const int DRIVER_PIN5 = 8; const int DRIVER_PIN3 = 9; const int DRIVER_PIN6 = 10;

boolean on_off=0; boolean got_data=0; String data=""; #include

const byte ROWS = 4; const byte COLS = 3; char keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'} }; byte rowPins[ROWS] = {35,37, 39, 41}; byte colPins[COLS] = {43, 45, 47}; Three phase frequency converter

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Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS ); boolean ok=0; void setup() { count1 = 0; pinMode(DRIVER_PIN1, OUTPUT); pinMode(DRIVER_PIN2, OUTPUT); pinMode(DRIVER_PIN3, OUTPUT); pinMode(DRIVER_PIN4, OUTPUT); pinMode(DRIVER_PIN5, OUTPUT); pinMode(DRIVER_PIN6, OUTPUT); digitalWrite(DRIVER_PIN1, LOW); digitalWrite(DRIVER_PIN2, LOW); digitalWrite(DRIVER_PIN3, LOW); digitalWrite(DRIVER_PIN4, LOW); digitalWrite(DRIVER_PIN5, LOW); digitalWrite(DRIVER_PIN6, LOW); delay(100); lcd.begin(16, 2); lcd.print("VFD "); lcd.setCursor(0,1); lcd.print("System"); delay(2000); on_off=1; lcd.clear(); lcd.print("Enter Frequency!"); lcd.setCursor(0,1); ok=0; Three phase frequency converter

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String datav=""; do { char key = keypad.getKey();

if (key){ if(key=='#') { datav=""; lcd.clear(); lcd.print("Enter Frequency!"); lcd.setCursor(0,1); }else if(key=='*') { ok=1; }else { datav+=key; } lcd.print(key); } }while(ok==0); lcd.clear(); lcd.print("Freq-->"); int uu=datav.toInt(); lcd.print(uu);lcd.print(" Hz"); float nf=(float)1/uu; Three phase frequency converter

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nf=nf*1000*1000; float nf1=nf/6; unsigned int nb=nf1; STEP_TIME=nb; lcd.setCursor(0,1); int yyyy=nf; lcd.print(yyyy);lcd.print("<=>"); lcd.print("(");lcd.print(STEP_TIME,1);lcd.print(")<=>"); } void all_off() { digitalWrite(DRIVER_PIN1, LOW); digitalWrite(DRIVER_PIN2, LOW); digitalWrite(DRIVER_PIN3, LOW); digitalWrite(DRIVER_PIN4, LOW); digitalWrite(DRIVER_PIN5, LOW); digitalWrite(DRIVER_PIN6, LOW); } void loop() {

if(on_off) { delayMicroseconds(STEP_TIME); switch(count1) { case 0: digitalWrite(DRIVER_PIN4, LOW); delayMicroseconds(DEAD_TIME); Three phase frequency converter

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digitalWrite(DRIVER_PIN1, HIGH); break; case 1: digitalWrite(DRIVER_PIN5, LOW); delayMicroseconds(DEAD_TIME); digitalWrite(DRIVER_PIN2, HIGH); break; case 2: digitalWrite(DRIVER_PIN6, LOW); delayMicroseconds(DEAD_TIME); digitalWrite(DRIVER_PIN3, HIGH); break; case 3: digitalWrite(DRIVER_PIN1, LOW); delayMicroseconds(DEAD_TIME); digitalWrite(DRIVER_PIN4, HIGH); break; case 4: digitalWrite(DRIVER_PIN2, LOW); delayMicroseconds(DEAD_TIME); digitalWrite(DRIVER_PIN5, HIGH); break; case 5: digitalWrite(DRIVER_PIN3, LOW); delayMicroseconds(DEAD_TIME); digitalWrite(DRIVER_PIN6, HIGH); break; Three phase frequency converter

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} count1 = (count1 + 1) % 6; }else { all_off(); }

}

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REFERENCES

1. Robert W. Erickson and Dragan Maksimovic. Fundamentals of Power Electronics. Kluwer Academic Publishers, 2nd edition, 2001. 2. Undeland Mohan and Robbins. Power Electronics: Converters, Applications and Design. Wiley Sons, 3rd edition, 2003. 3. Rotary converters: https://en.wikipedia.org/wiki/Rotary_converter 4. Muhammad H. Rashid. Power Electronics Handbook. 5. Butterworth-Heinemann, 3rd edition, 2011. 6. Stephen, Valantina; Suresh, L. Padma and Muthukumar, P.. "FIELD PROGRAMMABLEGATE ARRAY BASED RF-THI PULSE WIDTHMODULATION CONTROL FOR THREE PHASE INVERTER USING MATLAB MODELSIM COSIMULATION", American Journal of Applied Sciences, 2012. 7. Man-Chung Wong. "80C196MC microcontroller based inverter motor control and IR2130 six output. 8. IGBT driver", IEEE International Electric Machines and Drives Conference IEMDC 99 Proceedings (Cat No 99EX272) IEMDC-99,1999. 9. Three phase inverter: https://www.coursehero.com/ 10. Abu-Rub "Five-Phase Induction Motor Drive System", High Performance Control of AC Drives with MATLAB/Simulink Models Abu-Rub/High Performance Control of AC Drives with MATLAB/Simulink Models, 2012. 11. Opemipo Ogunkola, work in embedded systems:https://www.quora.com/How-does-thearduino-work-What-does-each-component-do-How-does-it-all-come-together. 12. Bose, Upama, K. Divya, Vallathur Jyothi, and Sreejith S.. "Performance analysis of four switch three-phase inverter-fed induction motor drive", 2014 POWER AND ENERGY SYSTEMS TOWARDS SUSTAINABLE ENERGY, 2014.

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13. Sun Chunxiang. "Design of Control System of Brushless DC Motor Based on DSP", 2010 International Conference on Intelligent Computation Technology and Automation, 05/2010 14. Book of "Power Electronics: Converter, Application and Design." by NED MOHAN. 15. VFD basics: http://www.gozuk.com/blog/vfd-basics-864930.html 16. http://www.robotshop.com/media/files/PDF/ArduinoMega2560Datasheet.pdf 17. 3-Phase Bridge Driver IC (IR2130): http://datasheet.eeworld.com.cn/ 18. IGBT driver IC: www.surplustronics.co.nz

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