21
MXZ MICROPROCESSOR CONTROL
3
3-1. INVERTER SYSTEM CONTROL
MXZ-A•NA
POWER
SUPPLY
NOISE
FILTER
CIRCUIT
RESISTOR
RELAY
SMOOTHING
CAPACITOR
CURRENT
TRANSFORMER
COMPRESSOR
REACTOR
P
W
V
U
N
IPM
PFC
U
W
MS
3~
V
+
3-1-1. Inverter main power supply circuit
Function of main parts
NAME FUNCTION
INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor.
SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.
CURRENT TRANSFORMER
It measures the current of the compressor motor.
It measures the current of the main power supply circuit.
REACTOR
It rectifi es AC, controls its voltage and improves the power factor of power
supply.
POWER FACTOR CORRECTION MODULE (PFC)
RESISTOR It restricts rush current with the resistance.
RELAY
It short-circuits the resistance which restricts rush current during the compres-
sor operates.
3-1-2. Outline of main power supply circuit
1. At the start of operation
Main power supply circuit is formed when RELAY is turned ON at COMPRESSOR startup.
To prevent rush current from running into the circuit when power supply is turned ON, RESISTOR are placed in sub circuit.
2. At normal operation
When AC runs into noise fi lter P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT.
After noise being eliminated from AC, it is rectifi ed to DC by REACTOR and PFC. If the operating frequency becomes 25
Hz or more, DC voltage rises to 370 V.
DC voltage, to which has AC been rectifi ed by process , is stabilized by SMOOTHING CAPACITOR and supplied to IPM.
The DC (Bus voltage), which has been stabilized in process , is converted to three-phase AC by IPM and supplied to
COMPRESSOR.
CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, are used to measure the val-
ue of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed
voltage and frequency with those information.