AN828 Datasheet, PDF (1/3 Pages) STMicroelectronics – 1500W - 440V POWER FACTOR CORRECTOR

AN828
®
APPLICATION NOTE
1500W - 440V POWER FACTOR CORRECTOR
PREREGULATOR
The application here described has been tailored
to supply a three phase inverter for motion con-
trol (see fig.1). To reduce the current in the
switches of the inverter, the output voltage of the
power factor has been held quite high.
The target specification of the PFC application is:
Mains supply Vin(rms)
Output Voltage Vout
Output Power Pout
= 220Vac ±20%
(f = 50/60Hz)
= 440Vdc
= 1500W
A switching frequency of 60kHz has been chosen
as a good compromise between requirements of
small size magnetics and low switching losses.
For this application a full isolated ISOTOP(TM)
STE30NA50-DK has been used.
This module is especially intended for boost appli-
cations and consists off the integration of a low
RDS/500V Mosfet with a TURBOSWITCH(TM) di-
ode.
The use of the module allows a compact and ef-
Figure 1: Schematic Diagram
fective solution in terms of layout and power dis-
sipation. The output stage of the L4981A/B is ca-
pable of driving directly the module without the
aid of a buffer stage. The L4981A controller is
supplied by the auxiliary of the boost inductor, a
Graetz bridge and a simple resistor for the start-
up phase. The Output capacitor filter has been re-
alized connecting in parallel four tap in "series"
configuration. This solution allows the use stand-
ard parts, in terms of the rated voltage, resulting
easier to be implemented in comparison with a
"single" configuration. To be noted that the high
frequency filter (C1 + C2) has been split in two
parts. In this way it is possible to held a low value
capacitor (C2) connected to the output of the rec-
tifier bridge, minimising the harmonic distortion
(introduced by the rectified DC contents). On the
other hand, the capacitor (C1) connected to the
AC side of the bridge, performs most of the high
frequency filter function without introducing DC
content.
The schematic circuit is shown in fig.1
T
STE30NA50-DK
C2
220nF
R4
FUSE
1M
10A/250V
C1
2.2µF
Vi
250V
176VAC/265VAC
BRIDGE
+ KBPC25-04
-
4
1
R3
75K
1W
R5
47
500mW
19
D2
4x
1N4150
Dz 18V 500mW
C6 330nF
C4 220µF 25V
R10 120K 5% R11 3.9K 5%
13
14
3
7
L4981A
6
20
R1
5.1K
1%
11
285
9
R6 100K
5%
C3
330nF
R2
R8
220
3.9K
1%
5%
R9
3.9K
5%
R_S 10mΩ
Transformer
Core: THOMSON - CSF GER55x28x25
Gap: 3.1mm for a total primary inductance of 440µH
Primary: 42 turns of 8x0.5mm (#24 AWG)
Secondary: 4 turns of #27 AWG (0.15mm)
18
17
12
10
C5
R7
105nF ^27K
1%
C7
10µF
16V
R12 15 5%
R13
1 5%
D3
1N4150
R14
820K
1%
R16
909K
1%
Rx
150K
Rx
150K
R15 R17
10K 10K
1%
1%
D95IN249C
+
Po=1500W
Vo=440V
4x
470µF
315V
4x
470µF
315V
Co
1µF
630V
-
October 2002
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