Avr For At90pwm

AVR for MOTOR CONTROL - AT90PWM October 2005 Jean Desuché

© Atmel Norway 2005

Motor Control Applications: PWM3 Focus • 3 Phase Brushless DC Motor • • • • • • • • •

HVAC Refrigerators Fans Pumps High tech Industrial, constant speed applications Traction elevator Medical equipment Hard disk, CD drives Automotive

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• 3 Phase Induction AC Motor • HVAC (Heating, Ventilating, Air Conditioning) • Washing machine • Blowers • Fans • Pumps • Industrial control

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AT90PWM Family Range AT90PWM1

AT90PWM2

AT90PWM3

Pins

24

24

32

I/O's

19

19

27

Flash

4 KB

8 KB

8 KB

SRAM

256 B

512 B

512 B

EEPROM

256 B

512 B

512 B

8 ch, 10-bit

8 ch, 10-bit

11 ch, 10-bit

Yes

Yes

Two

2

2

3

ADC Amplifier Analog comparator D/A

10-bit

Timer 8b

1

1

1

Timer 16b

1

1

1

PWM channels (timer)

3

3

4

Timer 12b: PSC

2

2

3

PWM channels (PSC)

4

4

6

• Features available in All AT90PWM : • ISP, One pin DebugWire, RC oscillators, UART • 64 MHz PLL for PSC & core (16 MHz), Vcc=2.7-5.5V www.atmel.com

AVR FAE Training 2005

3-phase BLDC Motor Basics C

U

Stator +

V C

W

Six possible Magnetic field values one rotor revolution

N

S

C

Sensor mode : • Rotor position with Hall sensor

U

Sensorless mode :

V

• Rotor position with Back EMF on floating coil

W www.atmel.com

Rotor

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BLDC Motor Application

Hall sensors to INT (sensor)

From PWM Channels

M 3 90 PW AT

AT 9

0P W

M 3

Back EMF to ADC (sensor-less)

0 1 2 3 4 5

D R I V E R S

0

2

+

C

V

1

3

To amplifier and ADC for regulation To comparator for emergency stop

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4

C

U

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5

N S

C

W

AC Induction Motor Basics U

C Stator

+

V C

Rotor

W

Rotating field with scalar or space vector modulation U

V

W www.atmel.com

AVR FAE Training 2005

C

Three Phases Induction AC Motor Application

Hall sensors to INT

From PWM Channels

M 3

AT 90 PW

AT 9

0P W

M 3

Tachimeter to ADC

0 1 2 3 4 5

D R I V E R S

0

2

+

C

V

1

3

To amplifier and ADC for regulation To comparator for emergency stop

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4

C

U

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5

C

W

Target applications AT90PWM1 AT90PWM2 AT90PWM3

BLDC motor with Hall sensor

x

x

BLDC motor with Hall sensor +AC/DC converter(PFC) BLDC motor sensorless

x Vs Motors

3-phase Induction AC motor

x x

DC motor

x

2 DC motors +AC/DC converter(PFC)

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x

x x

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AT90PWM3 : Key Advantages For Motor Control • PSC • 6 synchronized PWM channels for 3 phase motors • Fast emergency shut down of PWM outputs (only few 10 ns) • 64 MHz PLL, providing 12-bit PWM accuracy up to 16 KHz.

• ADC and Amplifier • Feedback control and current & power regulation • Possible synchronous current measurement

• Three comparators for Back EMF for Sensorless motors • DAC for variable comparator threshold (10-bit resolution) • Performances with a 3 phase BLDC with Hall sensors • CPU • Code • RAM www.atmel.com

18% with 8 Mhz oscillator, 14 K RPM 3175 bytes (38%) 285 bytes (55%) AVR FAE Training 2005

Requirements for a 3-phase BLDC Motor Control MCU P1

P2

P3

P4

P5

P6

P1

P2

0

0

2

4

1

2

U V W

+ -

3

4

5

1

3

5

U

V

W

• Up to 6 Synchronous PWM channels (12 bit precision or more) • PWM Timer Min clock frequency = 20MHz for 10 bit accuracy • According to schemes : Minimum dead time controlled by hardware for all 6 channels • All PWM must be disabled by hardware (Input) when overcurrent • Capability to support the 4 PWM schemes for BLDC control + the sinusoidal PWM mode • 4MIPS for 3 phase BLDC with Hall sensors, more for sensorless • Exemple above shows 1 PWM scheme (4 Quadrant Switching Simultaneous) www.atmel.com

AVR FAE Training 2005

Requirements for a 3-phase AC Motor Control MCU PWM cycle

0

2

U

4

0

U V W

+ -

V

1

2

W

3

1

3

5

PWM cycle

4

5

Mandatory min. Dead Time

• Up to 6 Synchronous PWM channels (12 bit precision or more) • PWM Timer Min clock frequency = 64MHz for 12 bit precision, 12KHz • Minimum dead time controlled by hardware for all 6 channels • All PWM must be disabled by hardware (Input) when overcurrent • Capability to support Scalar Algorithm and Space Vector Algorithm • 10 to 16 MIPS for 3 phase AC induction with Space Vector Algorithm www.atmel.com

AVR FAE Training 2005

MC100 : BLDC Motor Control Demo Board • Uses AT90PWM3 • Power bridge for BLDC motors • Interface for Hall Sensor • Interface for Sensorless mode (Zero crossing Back EMF detection ) • Hardware overcurrent detection • Voltage operation from 8V to 14V DC • ISP connector for on-chip ISP • On Board LIN transceiver Atmel ATA6661 • Includes BLDC motor • Software • Sensor mode with PID speed regulation www.atmel.com

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MC200 : Induction Motor Demo Board • Uses AT90PWM3 • IPM (Intelligent Power Module) to drive 3 phase induction motors • Interface for speed & position Sensor • Hardware overcurrent detection • Voltage operation from 110 to 230V • ISP connector for on-chip ISP

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AVR FAE Training 2005

www.atmel.com

AVR FAE Training 2005