Mitsubishi Electronics MSZ-ANA, MS-AWA manual Inverter System Control, MUZ-A09/12/15/17 MUY-A15/A17

2-7. INVERTER SYSTEM CONTROL

2-7-1. MUZ-A09/12/15/17 MUY-A15/A17

2-7-1-1. Inverter main power supply circuit

POWER P.C. BOARD INVERTER P.C. BOARD

L62	L63	L61
		DB61	U
Power	R64A R64B
supply		C63A P		CT761
		+ C63B	V
	X64	C63C
			N
	CT		W
			IPM	CT781
		TR821
		DB65
		Booster chopper circucuit

W

MC

U

V

Function of main parts

SYMBOL	NAME		FUNCTION
IPM	INTELLIGENT POWER MODULE	It supplies three-phase AC power to compressor.
C63A/C63B/C63C	SMOOTHING CAPACITOR	It stabilizes the DC voltage.
CT761/CT781	CURRENT TRANSFORMER	It measures the current of the compressor motor.
CT	CURRENT TRANSFORMER	It measures the value of current which is supplied to the main power
		supply circuit.
DB61	DIODE MODULE	It converts the AC voltage to DC voltage.
R64A, R64B	CURRENT-LIMITING RESISTOR	It absorbs the rush current not to run into the main power supply circuit
		when the electricity turns ON.
X64	RELAY	It short-circuits the resistance which restricts rush current during the
		normal operation after the compressor startup.
DB65	DIODE MODULE	Booster	It improves power factor.
TR821	SWITCHING POWER TRANSISTOR	chopper
			It rectifies AC and controls its voltage.
		circuit
L61	REACTOR

2-7-1-2. Outline of main power supply circuit

1.At the start of operation

Main power supply circuit is formed when X64 (Relay) is turned ON at compressor startup. To prevent rush current from running into the circuit when power supply is turned ON, R64A and R64B (Current-limitting resistor) are placed in sub circuit.

2.At normal operation

1 When AC runs into POWER P.C. board, its external noise is eliminated in the noise filter circuit.

2 After noise is eliminated from AC, it is rectified to DC by DB61 (Diode module).

3 DC voltage, to which AC has been rectified by process 2, is stabilized by C63A, C63B and C63C (Smoothing capacitor) and supplied to IPM (Intelligent power module).

4 DC voltage, which has been stabilized in process 3, is converted to three-phase AC by IPM and supplied to compressor.

5 CT761 and CT781 (Current Transformer), which are placed in the power supply circuit to compressor, are used to measure the value of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed voltage and frequency with those information.

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