study of series resonant converters
TRANSCRIPT
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
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Circuit Details and Design Methodology
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What is SRC???
• SRC and switching losses
• ZVS and ZCS mode of switching
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Circuit Details (1)
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Circuit details (2)
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The SRC design
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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
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The State Plane Analysis
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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???
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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
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State Space Analysis (2)
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'
'
1 /0 0'
01 1'
Lc
e cL
cc
EL
L
iV
Cv v
IL
C vVV
I iL L
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State Space Analysis (3)
Class of differential equations
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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
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State Space Analysis (4)
• After normalization
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• Now to the state planesin
cosLN
CN
i a
v a
center at (0,VEN )
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Continuous Conduction Mode
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CCM ( below resonance)
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• 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
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Simulation Results (1)
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• 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
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Simulation Results (2)
• Capacitor Voltage
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• 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
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CCM (above resonance)
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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
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Discontinuous Conduction mode
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DCM
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• 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
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Simulations Results (1)
• Inductor current
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• 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
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Simulations Results (2)
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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
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ASTD-IC
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• Conduction sequenceQ1->Q2->D1->D2
• Time ta is critical
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Conclusions
• CCM/DCM boundary frequency less than the calculated
• Transients in initial cycles• ASD-TIC implementation
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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;
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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;
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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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