Transcript UCI Power Electronics Lab

UCI
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UCI Power Electronics Lab
Control of A Dual-Boost Power Factor Corrector
for High Power Applications
Yaoping Liu and Keyue Smedley
University of California, Irvine, CA 92697
Shenzhen WATT Electronics Co., LTD.
10/11/03~15/11/03
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UCI Power Electronics Lab
outlines
 Dual boost converter for high power PFC
application
 PFC control method review
 Proposed PFC control method for the converter
(One cycle control method for PFC application)
 Stability analysis for the control method
 Experimental results
 Conclusions
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UCI Power Electronics Lab
Popular configuration for practical power supply productions
Vac
uninsulated
VRM
PFC
DC/DC
PFC is necessary and very
important for most of ac/dc power
supply, and boost converter is
used for single phase PFC:
SIP
LOAD
insulated
DC/DC
Advantages:
•Simpler circuit configuration;
•adaptability to wide range input voltage;
•higher efficiency;
•relatively lower component stress.
But for higher power level application, the
boost converter has some limitations
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Dual boost converter for high level power PFC application
When the converter operates under CCM,
the conversion ratio is:
M (d ) 
Vo
1

Vg 1  d
Traditional control method:
•voltage follower approach;
large current stress,
significant residual current harmonics
•Multiplier approach
circuit complex;
additional current distortion due to the
nonlinearity of the multiplier
high cost
inconvenience of sensing the input
voltage and the input current
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The approach of PFC using PWM modulator
Control goal:
Vg = Re • ig
Where Re is equivalent
input resistor of DC/DC
converter
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CONSTRACTION:
• A constant frequency
clock generator
• A flip flop
• An integrator with
reset switch
• A comparator
occ core
•The time coefficient of the
integrator is selected to
equal the switching period
Ts;
•V2 can be considered as
constant during one cycle
period;
•For time t from the
beginning of a cycle to the
moment when v+ = v1, the
duty ratio of Q is d.
v2 t
Ts
v  v1
When d represents
duty ratio for Q
high and take Q as
driver signal then:
t  dTs
v1  (1  d )v 2
v 
0  t  Ts
v1  v2 d
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The approach of PFC for the dual boost converter using OCC core
V1= V2d
Vm – Rs * ig = Vm* d
Vm = RsVo/Re
So control goal
Vg = Re * ig
is realized
So control goal
V1 = V2 (1 – d)
Rs* ig = Vm (1 – d) Vg = Re * ig
is realized
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The stability analysis for the control method
1. The Stability Of The Trailing Edge Modulation.
Vm  Rs i Lin  Vm d
i.e.
i Lin 
Vm
V
 m dTs
Rs Rs Ts
Define:
mc 
m1 
Then,
m2 

Vm
RsTs
m  m2
m2
 c
d
m1  m c m1  mc
mc  m 2
m1  mc
if
d* 
m2
m1  m2
d n  d * (1   n )   n d 0
 1
Vg
Lin
Vo  V g
Lin
mc d nTs  m2 (1  d n )Ts  (m1  m c )d n 1Ts
d n 1 
f (d ) 
The duty ratio converges,
so the stability condition
is:
d
m  m2
m2
 c
dn
m1  m c m1  mc
2. The stability condition for leading edge
modulation
d
1 Lin f s

2
Re
1 Lin f s

2
Re
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Experimental verification
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Conclusion
• A single-phase dual boost PFC rectifier using general constant
frequency PWM control method is presented, And the
converter can handle high power with a simple configuration;
• The multiplier and the sensor for input voltage are not needed;
• The control method is very simple and reliable which
achieves low total harmonic distortion and high a power
factor at low cost;
• Analyses for the topology and control method are provided,
and experiment verification is provided.