Hitachi RAS-50WX8 Service Manual page 113

12. Increasing DC Voltage (Vd)
DC Voltage is detected by microcomputer and is then increased to value matching rotation speed. Basic configuration is
voltage-increasing chopper circuit:
Q1 is chopped by high frequency and current (I
capacitor during OFF period.
Adjust Q1 chopper duty so that current charged in reactor matches current consumed by inverter. ( For hight
speed and high load, DC voltage increases as duty increases.)
Reactor
IC
Analog voltage
D-pass filter
Command voltage
(PWM output)
) flowing during is charged in reactor, then discharged (I
1
– 154 –
ACT module
Q1
I
1
I
2
Microcomputer
DC voltage
Compressor
P
M
) to
2