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Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
Control logic
1.1 Basic principle
Basic principle is to control the RPM of the motor by changing the working frequency of the compressor.
Three phase voltage is supplied to the motor and the time for which the voltage will supplied is controlled by IPM
(intelligent power module).
Switching speed of IPM defines the variable frequency input to the motor.
1. Compressor
BLDC Motor
IPM (Inverter)
EMF
MCU
(16Bits)
U
V
W
U V W X Y Z
Position
Detect
Circuit
120 f
P
RPM
→
→
→
f
P
RPM =
Revolutions/Minute
Frequency
Number of poles