Study of series resonant converters

Study of Series Resonant Converters

5N280 :Mini Power Electronics , Q1

28th October,2010

Mayur Sarode0730085Electrical engineering

Electrical Engineering 12-04-2023

About the presentation…

• Analysis/implementation of a series resonant converter

Ramesh Orunganti and Fred C Lee , “ Resonant Power Processors, Part 1-State Plane Analysis”.

• Simulations results from ADS agilent 2008

• SPA (State plane analysis) : derivation /explanation

• Continuous /Discontinuous mode of conduction

• Conclusions

PAGE 2

/ name of department 12-04-2023

Circuit Details and Design Methodology

PAGE 3


What is SRC???

• SRC and switching losses

• ZVS and ZCS mode of switching

PAGE 4


Circuit Details (1)

PAGE 5


Circuit details (2)

PAGE 6


The SRC design

PAGE 7

1

2 1 1rf

L C

sfDesign of half bridge • Switching frequency of half bridge Gate peak to peak= 160 volt

Design of resonant tank

• Transistor biasing : operating in saturation region

20feh

max 15Ic A

cfe

b

Ih

I

The base resistance was calculated to be 215 Ω

= 5KHz

SRC ~ 100 volt buck converterMode of operation Range

CCM1 ω0/2<ω<ω0 6.2 KHz to 12.58 KHz

DCM ω<ω0/2 ω<6.2 KHz

CCM2 ω>ω0 ω>6.2 KHz


The State Plane Analysis

PAGE 8


State Plane Analysis (1)

How to construct a State Plane?

• Identify the state variables /sources

• Determine the initial conditions of the state variables

• Form a 2nd order differential equation matrix

• Transform to time domain

• Represent as a equation of a circle (parameterized )

• No. of circle on state planes~~ no of conduction states

• Circle or a semi circle???

PAGE 9


State Plane Analysis

• Sinusoidal approximations Vs state Plane

• What is

“State” and “Plane”• How is it useful?

1. Tank energy

2. Operational sequence

3. Boundary conditions

4. Time elapsed

PAGE 10


State Space Analysis (2)

PAGE 11

'

'

1 /0 0'

01 1'

Lc

e cL

cc

EL

L

iV

Cv v

IL

C vVV

I iL L



Class of differential equations

PAGE 12

General solution

0

0

/

/ CO

L t t LO

C t t

i I

v V

10 2 0

1 0 2 0

sin( ( )) cos( ( ))

sin( ( )) * cos( ( ))

L

c E

ci t t c t t

Zv V c t t Z c t t

ω is the eigen value

c1 and c2 are found from initial conditions

1

LZ

C

LC



• After normalization

PAGE 13

• Now to the state planesin

cosLN

CN

i a

v a

center at (0,VEN )


Continuous Conduction Mode

PAGE 14


CCM ( below resonance)

PAGE 15

• ZCS switching

0.715

81.65CO

LOI A

V volt

For the Q1 state at t=0

0<t<t1 , Q1 t1<t<t2, D1

t2<t<t3, Q2 t3<t<t4,D2

For the D1 state at t=t1

0.6932

88.2CO

LOI A

V volt

0

120.8CO

LOI A

V volt

For the Q2 state at t=t2

For the Q2 state at t=t30.004696

91.2CO

LOI A

V volt


Simulation Results (1)

PAGE 16

• Inductor Current

• Gate pulse Ts=200μ sec

0.2 0.4 0.6 0.80.0 1.0

20

40

60

80

0

100

time, msec

vg1_1-v

g1_2

0.2 0.4 0.6 0.80.0 1.0

20

40

60

80

0

100

time, msec

vg2, V


Simulation Results (2)

• Capacitor Voltage

PAGE 17

• Output Current

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90.0 1.0

0

2

4

6

8

10

12

-2

14

time, msec

I_P

robe2.i,

Ay

Readout

m1

m1indep(m1)=plot_vs(y,time)=4.187

4.646E-4


CCM (above resonance)

PAGE 18

20 40 60 80 100 120 140 160 1800 200

0

5

10

-5

15

time, usec

I_P

robe

2.i,

A

20 40 60 80 100 120 140 160 1800 200

-18-16-14-12-10-8-6-4-202468

1012141618

-20

20

time, usec

vg1_1-v

g1_2

I_P

robe3.i,

A• ZVS switching• D1->Q1->D2->Q2• S1 found by equating Q1 and D2• S2 found by equating Q2 and D1

Ts =50 μ sec

D1

Q1 D2

Q2


Discontinuous Conduction mode

PAGE 19


DCM

PAGE 20

• Switching frequency • Conduction mode: Q1->D1->X->Q2-

>D2• Low switching losses• Large transients

Ts= 450 μ sec

0

2s

Von=0

Von=1

Von=0

Von=1


Simulations Results (1)

• Inductor current

PAGE 21

• Capacitor voltage

0.2 0.4 0.6 0.80.0 1.0

-100

-50

0

50

100

-150

150

time, msec

vc2-v

c1

0.2 0.4 0.6 0.80.0 1.0

-18-16-14-12-10

-8-6-4-202468

1012141618

-20

20

time, msecvg

1_1-v

g1_2

I_P

robe3.i,

AL cv v


Simulations Results (2)

PAGE 22

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90.0 1.0

0

2

4

6

8

10

12

-2

14

time, msec

I_P

robe2.i, A

• Output Current


ASTD-IC

PAGE 23

• Conduction sequenceQ1->Q2->D1->D2

• Time ta is critical


Conclusions

• CCM/DCM boundary frequency less than the calculated

• Transients in initial cycles• ASD-TIC implementation

PAGE 24


Appendix(1)

• Matlab code• %creating a state space diagram of a series resonant converter• %vs=100 vo is output voltage• % for switch when Q1 is on• %plotting values from ADS• data_iln= importdata('C:\Documents and Settings\rooster\My Documents\MATLAB\Iln.txt');• data_vcn= importdata('C:\Documents and Settings\rooster\My Documents\MATLAB\Vcn.txt');• data_vcn=data_vcn';• data_iln=data_iln';• subplot(2,2,1);• plot(data_iln(1,:),data_iln(2,:));• grid on;• subplot(2,2,2)• plot(data_vcn(1,:),data_vcn(2,:));• grid on;• L=80e-6;• C=2e-6;

PAGE 25


Appendix(2)

• Vs=100;• Vo=10;• Ilo=0.715;• Vco=120.8;• Zo=(L/C)^0.5;• w=1/(L*C)^0.5;• In=Vs/Zo;• Vn=Vs;• %Ven=Vs/Vn-Vo/Vn;• Ven=1-Vo/Vn;• Ilon=Ilo/In;• Vcon=Vco/Vn;• rad=Ilon^2+(Vcon-Ven)^2;• rad=rad^0.5;• for i=1:143• q1_il(1,i)=data_iln(2,431+i)/In; • q1_vc(1,i)=data_vcn(2,431+i)/Vn; • theta(1,i)=atand((-q1_il(1,i)/(q1_vc(1,i)-Ven)))-atand((-Ilon/(Vcon-Ven)));• end• subplot(2,2,3)• b=rad*cosd(theta);• a=rad*sind(theta)+Ven;• plot(a,b);• hold on;• xlabel('Vcn');• ylabel('Iln');• %axis([-4 4 -2 2]);• grid on;

PAGE 26


References

[1] R. Oruganti and F.C. Lee, “Resonant Power Processors, Part 1: State Plane Analysis,” IEEE Transactions on Industry Application, vol. IA-21, Nov/Dec 1985, pp. 1453-1460.

[2] F. C. Schwarz, "An improved method of resonant current pulse

modulation for power converters, " IEEE Power Electronics Specialists

Conf. Rec., 1975, pp. 194-204.

[3] Lecture Notes 5LN280 , Tu/E

[4] Lecture notes of University of Colorado, Bolder , ecee.colorado.edu/~ecen5817/notes/ch4.pdf

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Education

Study of series resonant converters