Hitachi Summit RAC-50YH5, Руководство по обслуживанию

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6. Rotor magnetic pole position detection circuit
A
B
C
D
E
18
19
20
ret
up
moc
orci
mr
oo
dtu
O
C605
+5V
0V
HIC
0V
+12V
W V U
C608
System power module
DC brushless
motor for compressor
R604
R605
R606
R607
10
6
R
20
6
R
30
6
R
40
6
R
30
6
R
20
6
R
80
6
R
30
5
C
20
5
C
10
5
C
11
6
R
01
6
R
90
6
R
0V
C606
0V
C607
0V
36 33 34 35 47
Fig. 6-1 Rotor magnetic pole position detection circuit and voltage waveform at each point
E
D
C
A
No power
supplied
Upper arm
ON
No power
supplied
No power
supplied
Lower arm
ON
60 120 60 120
Induced voltage
Comparing process
60
Vd 150~330
Spike voltage
U phase
terminal voltage
Drive signal
Pole position
detection signal
(B) reference
voltage (1/2Vd)
Detection point
W+ W+ U+ U+
UÐ VÐ VÐ WÐ
V+
To detect U phase, voltage at point
C
is produced by driving motor induced voltage signal (voltage at point
A
) and
1/2 voltage of Vd (voltage at point
B
), and comparing with comparator.
For V phase and W phase, voltage at point
D
and voltage at point
E
are produced in the same way as above. Voltage
at point
C
is taken into indoor unit microcomputer, switching timing to U
+
transistor from W
+
transistor is produced by
delaying 30 from rise waveform, ignoring spike voltage. In addition, switching timing to U-transistor from W-transistor is
produced by delaying 30 from fall waveform.
For V phase and W phase, in the same way as above, drive signals are produced from voltages at point
D
and point
E
. Phases are shifted by 120° and 240 , respectively, comparing with U phase.