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 IGBTM
(intelligent power module).
Switching speed of IGBTM defines the variable frequency input to the motor.
1. Normal operation
Fuzzy control : Maintain evaporating temperature (Te) to be constant on cooling mode and constant condensing temper-
ature (Tc) on heating mode by fuzzy control to ensure the stable system performance.
2. Compressor control
Cooling and heating load
System capacity
Linear control
Inverter linear control as cooling and heating load increasing
Actuator
Cooling operation
Heating operation
Stop state
Compressor
Fuzzy control
Fuzzy control
Stop
Fan
Fuzzy control
Fuzzy control
Stop
EEV
Super heating
fuzzy control
Discharge Temp. Control
Min. Pulse
EEV operates with fuzzy control rules to keep The degree of superheat (2~3℃) or the target temperature of discharge pipe.
＊
Cooling mode
The degree of superheat = Tsuction – Tevaporator
Tsuction : temperature at suction pipe sensor(℃)
Tevaporator : evaporation temperature (℃)
3. EEV( Electronic Expansion Valve) control
＊
Heating mode
the target temperature of discharge pipe = T condenser +
α
T condenser : condenser temperature (℃)
Part 3 Basic Control
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