Inverter Main Power Supply Circuit; Outline Of Main Power Supply Circuit; At The Start Of Operation; At Normal Operation - Mitsubishi Electric MSH09TW Service Manual

10-10. INVERTER MAIN POWER SUPPLY CIRCUIT

MXZ30TN MXZ30TN2
10-10-1. Outline drawing of main power supply circuit
L61
L1
POWER
SUPPLY
L2

10-10-2. Outline of main power supply circuit

1. At the start of operation

Rush current is generated the instant the electricity is turned on to the main power
supply circuit to operate the compressor.
To prevent the rush current from running into the main power supply circuit, R(Current-limiting resistor) absorbs
the rush current.
After the rush current is absorbed, X64(Relay) is ON and the circuit to R is
short-circuited, then the electricity to R is bypassed.
When X64 is ON, the system starts the operation of compressor.

2. At normal operation

The noise of alternating current of power supply is eliminated by L61(Common mode choke coil).
Then DS61(Diode stack) performs full-wave rectification of alternating current and the
alternating current is converted to direct current.
C62, C63(Smoothing capacitor) stabilizes the power supply converted to direct current from alternating current and
supplies it to IPM(Intelligent power module).
Direct current rectified by DS61 is converted to three-phase alternating current by IPM.
Microcomputer installed in the electronic control P.C. board controls frequency and voltage of three-phase alternating
current converted by IPM.
Three-phase alternating current is supplied from IPM to the compressor with frequency and voltage decided by
microcomputer based on various kinds of information.
CT61,CT62(Current transformer) measures the current of main power supply circuit.
3. Power factor improvement of power supply
Unlike inverter-less alternating current circuit, the power factor of this inverter circuit is improved by extending the period
of the current running in the circuit.
C63 is used in this circuit to supply stable direct current voltage. However, in case only SMOOTHING CAPACITOR is used
for stable supply of direct current, the power factor of power supply is lowered because the period of direct current running
in the circuit is short.
Therefore, for improvement of power factor, the circuit also uses C61(Power factor capacitor), L61(Reactor) and
DS62(Diode stack) to prepare the direct current circuit to extend the period of the current running in the circuit.
ELECTRONIC CONTROL P.C. BOARD
R
DS62
DS61
C61
X64 A
+
+
K
-
-
NOISE FILTER
CT
P.C.BOARD
61
I.P.M P.C.
BOARD
C63
C62
L
+ +
- -
CT62
65
V
MC
U W