Basic Chpper

4.     4.1     (DC chopper)
    
 ก ก  
       
    ก  ! ก
  dc-dc

converter +

,! -ก+.  /0!-1ก2,/
      -  .  /3 ก 0 . ก  ก4  /  56 ก 4   -1 - 22 7
278 ก4/9  8 ก:  ;22ก/ 
0</! ก07
278 9 ก70  ก6=!4 (switching power supply) 6 229 
   
. +<I 511
!ก049 กJ/! -14/ (step-down chopper) !-1ก2,/ 1
!
 -6 0 4.1

2

6 0 4.1 ก049 
   ก6 0 4.1

. 7
278 ก ก ก/!   BJT, MOSFET, GTO  SCR 0 ก 272-1!84กก31 ,!7J/!9 0ก. 2,/  51ก t

t 1 1 Vav = ∫ V0 dt = 1VS = ft1VS = kVS T 0 T

/กJ/!0/;,/ 7 I av =

Vav kVS = R R

,! k = Tt   k 7 72
/
 (duty cycle) 1

(4.1)

3

3
7 k

 5  /!1ก 0-1 ,!ก

  /!72
/ ==: t1  T  f < V0   5  /!1ก 0 5 VS 1
!ก7
278 7 k   57
278 ก4/9 ,/1 ก7
278 7 k  5 041 2
.`7 1 ) ก   04      2 2 7
 5 7  0 (constant-frequency operation)  !572
/ T  7
 5 f 9 
70 - ก:<ก7
278 7 k 1   /!7
 ก
19 +/ t1   ก7
278 7
 ก
1  9 + /  <  ! ก
  cpulse-widthmodulation (PWM)g 2) ก0422  /!7
 5 (variable-frequency operation) -/กi:<7
 ก
19 +/ t1 / t2 70  7
 5 f  72
/ T 9 
 /! / !กก7
278 22<
 cfrequency modulation (FM)g 91 !9 ก7
278 22<7   57 !7
 5j .ก0ก.9<1 ก ก 7
 5+ /ก2ก
9 ==:041!ก

4

4.1.1 ก  !"#    ก049 
    52 7/ (class) ก041 5 l0 7 7/ A, B, C, D / E ,!2  / ก i:ก/9 ก/    0 , /   -1กก046 0 4.2

6 0 4.2 ก2 l09 
  

5

- Class A chopper: /กi:ก/9 ก/       1
!6 0 4.2(a) ,!ก/  !6-7
0 0 1 9 2ก (  2
ก0<76)  !5ก/916,//  9<
2
ก2,/ !!

7/ A 11
!6 0 4.3(a) /    ! E -
   /    !
9:ก;/9  1ก/2 (back EMF) 9 9/
 ก049 
2  2 ,  7 , 0 1 SW 
 (on) ก i1 / !,/ , 0 2 SW 
 (off) ก-,/!7/  1 ก freewheeling diode Dm

 
0 ! 20  -6 0 4.3(b) /6

7/   = =:9   /ก  0 , /1 - 6 0 4.3(c)

6

6 0 4.3
   7/ A

7

- Class B chopper: ก/ กก,//  2
ก /กi:9 /ก !6 -7
0 0 2 -6 0 4.2(b)

/ 
ก

041
!6 0 4.4  ก04-7
0 !
!
ก27/ A

6 0 4.4
   7/ B ก049 
7/ B 2  2 , ก 7 SW  /
   S1 
 /! E 92ก ;9/
 L /,/ R 9:07 ,/ VL  s6! /  S1 
 VL 92ก;,  D1 

!/! VS

8

- Class C chopper: ก049 
< ก0/; ,/ IL /0<12
ก//27 ,/ VL  9<
2
ก2,/ !!
 ก04- 2 7
 0 -6 0 4.2(c) / 
ก041
!6 0 4.5  ก04
ก
   7/ A / B ,!0 S1 / D2 04ก2
-/กi:9 7/ A 9:0 S2 / D1 04-/กi:7/ B ก7
278 ก049 
. 1  ก. S1 / S2 04+1 ก +  กก/
 9 /! VS

6 0 4.5
   7/ C - Class D chopper: ก049 
 ก/; ,/ 2
ก/ 
/ 7 ,/ก.0< 12
ก//2 04- 2 7
0 -6 0

9

4.2(d) / 
ก041
!6 0 4.6 51 S1 / S4 
 VL / IL  2
ก 51 S1 / S4 
 ก IL  2
ก//   ,  D2 / D3  0; 9 ก,/ 9:0 VL  /! 9<
/2

6 0 4.6
   7/ D - Class E chopper: ก,//0<12
ก//2 
57 ,/ก3 /! 2
ก//21
! ก04<04-/กi: 4 7
0 -6 0 4.2(e) 6 22ก04 ก04
ก9    7/ C  8 ,! 9<
//กi:ก049 
 1
!6 0 4.7  /42

10

6 0 4.7
   7/ E 4.1.2 % ก"&'# ()*ก&)+,--. /0102 (switching-mode regulator)
      54   1  
/    ! ก4/ก07
278 9 ก-170 (switching power supply) ,! 6 22ก049 
- 4 /กi: 1
!ก 1ก Buck regulator, Boost regulator, Buck-Boost

11

regulator / Cuk regulator ,!-0< `.2!1J+  22ก /ก+ 22+<I0.! -1ก,!0


- Buck regulator: 
78 7222ก7  0.! -1-
 /!22
.. -179 กJ/!9 
 Va 74ก
/! VS
< ก-10.  . BJT   
   11
!6 0 4.8(a) (0!27!1ก2   7/ A) ก042  2 , 7 , 0 1 0.  Q1 
0 t1 = 0 กก/!/;
ก  ก L / C ;,/ , 0 2 0.  
0 t1 
< freewheeling diode Dm 4ก ก+/  -9/
 L ก/  ; L, C /,/ กก+/   9 9/
//ก0  0.  
 ก7<-
 2ก04 
 0!20ก049 , 0< -6 0 4.8(b) /1 6 ==:/ก1-6 0 4.8(c)
 <-1 .0`.l+65 90%

12

6 0 4.8 Buck regulator

13

ก
0 4.8 ก7 9/
!
4 ,! VL = L

di dt

1

-ก:51ก-9/
!
4 iL  /! /ก I1 5 I2 -

/ t1 VS − Va = L

(4.2)

(I 2 − I1 ) ∆I =L t1 t1

 t = V∆I−LV

(4.3)

1

S

a

-ก:ก-9/
//ก I2 5 I1 -

/ t2 0 − Va = − L

 t

2

=

∆I t2

(4.4)

∆I L Va

(4.5)

ก /! /9 ก ∆I = I

2

− I1

7 ก.  z/ (p-

p) 9 9/
 ก ก0 (4.2) / (4.4) 1 ∆I =

(VS − Va )t1 Va t 2 = L L

07 t = kT / t 1

Va = V S

t1 = kVS T

2

= (1 − k )T

  T = t + t 1 1

2

(4.6)

14

 8.

  ก6=! V I S

S

= Va I a = kVS I a

17J/!

ก9 /!  (4.7)

I S = kI a

72
/
. (T)  5ก! 0 9  ก1 < T=

∆I LVS ∆I L ∆I L 1 = t1 + t 2 = + = f V S − Va Va Va (VS − Va )

(4.8)

-7
 5<ก ก0 (4.8) 04-1ก.  z/ (pp) 7 ∆I =

(4.9)

Va (VS − Va ) fLVS

 ∆I = V k (fL1 − k )

(4.10)

S

ก KCL; i

L

= i C + iO

ก04  9 
<  io  / !  /1 ! ก   <  ∆i L = ∆iC IC =

∆I 4

กJ/!9  IC

/-

/

t1 t 2 T + = 2 2 2

7

15

-9:0ก7 
ก32 81ก vC =

1 iC dt + vC (t = 0) C∫

.  z/ (p-p) 9 
ก32 80ก2 ∆VC = vC − vC (t = 0) =

1 C

T /2

∫ 0

(4.11)

∆I T ∆I ∆I = dt = 4 8C 8 fC

  07 ∆I ก ก0 (4.9) /- ก0 (4.11)  1 ∆VC =

(4.12)

Va (VS − Va ) 8LCf 2VS

 ∆V

C

=

(4.13)

VS k (1 − k ) 8LCf 2


!0 4.1

78 7222ก7 -6 0 4.8 /! VS = 12 V 1 กJ/!9 ก Va = 5 V 07.  z/  20 mVp-p 7
 5

. 0ก2 25 kHz /51 .  z/ก (p-p) -9/
4ก0 0.8 A 74
: a) duty cycle b) 79/
ก ก / c) 77
 8ก ก Soln a) ก ก0 (4.6) V

a

= kVS

< k = VV

a

S

=

5 = 0.4167 = 41.67 % 12

16 12 − 5) b) ก ก0 (4.9) L = V (∆VIfV− V ) = 0.8 5×(25000 = 145.83 µH × 12 a

S

a

S

c) ก ก0 (4.11) C = 8 f∆∆IV

C

=

0 .8 = 200 µH 8 × 25000 × 20 × 10 −3

- Boost regulator: 
78 72226 -179 ก J/!9 
 Va

7 กก
/! VS
< ก-1

0.  . MOSFET  
   11
!6 0 4.9(a) (0!27!1ก2   7/ B) ก042  2 , 7 , 0 1 0.  M1 
0 t1 = 0 ก ก/!/;9/
 L /0.  , 0 2 0.  
 ก/; L, C ,/ / Dm ก-9/
// ! ก0 M1 
 ก7< +/0 - L 5!, -1,/
0!20 ก04  9 , 0<   -6 0 4.9(b) /1 6

==:/ก1-6 0 4.9(c) 3
9 ก+. 9< (step up) ก;/9 9/
,!  1 -1 1  / 9-=/ ก6=! ก

17

+ -1.  z/4
<-17 .  /9/
,ก
22 2ก7

6 0 4.9 Boost regulator

18

-ก:51ก-9/
!
4 iL +. 9<ก I1 5 I2 -

/ t1 1 VS = L

(4.14)

( I 2 − I1 ) ∆I =L t1 t1

 t = ∆VI L

(4.15)

1

S

-ก:ก-9/
//ก I2 5 I1 -

/ t2 V S − Va = − L

 t

2

=

(4.16)

∆I t2

(4.17)

∆I L Va − V S

ก /! /9 ก ∆I = I

2

− I1

7 ก.  z/ (p-

p) 9 9/
 ก ก0 (4.14) / (4.16) 1 ∆I =

VS t1 (Va − VS )t 2 = L L

07 t = kT / t 1

Va = V S

2

= (1 − k )T

  T = t + t 1 1

2

(4.18)

VS T = t 2 (1 − k )

 8 .
 
   ก 6 =  ! V I S

7J/!ก9 /! 

S

= Va I a = VS I a /(1 − k )

1

19 IS =

(4.19)

Ia 1− k

72
/
. (T)  5ก! 0 9  ก1 < T=

∆I LVa ∆I L ∆I L 1 = t1 + t 2 = + = f VS Va − VS VS (Va − VS )

(4.20)

-7
 5<ก ก0 (4.20) 04-1ก.  z/ (pp) 7 VS (Va − VS ) fLVa

(4.21)

 ∆I = VfLk

(4.22)

∆I =

S

-9:00.  
 
ก32 8!ก ,/-

/ t = t1 7J/!9 ก

/ t1 <7 IC = Ia /.  z/ (p-p) 9 
ก32 80ก2 t

t

I t 1 1 1 1 ∆VC = vC − vC (t = 0) = ∫ I C dt = ∫ I a dt = a 1 C0 C0 C

(4.23)

,! t = kT = (VV − Vf ) /  07 t1 - ก0 (4.23)  a

S

1

a

1

20 ∆VC =

I a (Va − VS ) Va fC

 ∆V

C

=

Iak fC

(4.24) (4.25)

21

- Buck-Boost regulator: 
78 7222ก7 -26  5-1 79 กJ/!9 
 Va  10<74ก
/6ก
 /! VS (!ก2ก7 -26 ) -19 ก0 9<
ก91 ก2/! 
78 7<11
!6 0 4.10

6 0 4.10 Buck-Boost regulator

22

- Cuk regulator: 
78 722<11
!6 0 4.11   /กi:  ก2
78 7 222ก7 -26  +!  2 8 

.0`.l+9 
-16!.9<

6 0 4.11 Cuk regulator