Fig. 9-3 Voltage waveform at each point
U
transistor chopped
Chopping period (208
μ
sec.)
Chopping period
T
transistor ON
U
280V-300V
Voltage at
V
V
Upper arm transistor
Current at
ON
+
-
A
B
V
Time
W
T
V
U
V
Upper arm
transistor
Lower arm
transistor
W
W
U
E
F
+
+
W
+
+
-
-
V
-
Fig. 9-2 Switching order of power module
Intelligent power module switches power supply current according to position of the compressor motor
rotor.
The switching order is as shown in Fig. 9-2.
At point
E
: U+ is ON, V- is ON (circuit in Fig. 9-1)
At point
F
: U+ is chopped (OFF), V- is ON (circuit in Fig. 9-4)
Upper arm transistor is controlled to ON/OFF by 2.5kHz-5kHz chopper signal. Rotation speed of the
compressor is proportional to duty ratio (ON time/ ON time + OFF time) of this chopper signal.
Time T in Fig. 9-2 shows the switching period, and relation with rotation speed (N) of the compressor is
shown by formula below;
N = 60/2 X 1/T
Fig. 9-3 shows voltage waveform at each point shown in Figs. 9-1 and 9-4. First half of upper arm is
chopper, second half is ON, and first half of lower arm is chopper, second half is ON.
When power is supplied U+
→
V- , because of that U+ is chopped, current flows as shown below;
(1) When U+ transistor is ON: U+ transistor
→
U coil
→
V coil
→
V- transistor
→
DC current detection
resistor
→
Point
B
(Fig. 9-3)
(2) When U+ transistor is OFF: (by inductance of motor coil) U coil
→
V coil
→
V-transistor
→
U- diode
→
Point
A
(Fig. 9-4)
73
Summary of Contents for RAC-25FPA
Page 2: ... DANGER 2 ...
Page 32: ...WIRING DIAGRAM OF THE PRINTED WIRING BOARD Remote controller RAR 5E2 32 ...
Page 33: ...MODEL RAF 25RPA RAC 35RPA 33 ...
Page 34: ...MODEL RAC 25FPA RAC 35FPA 34 ...
Page 39: ...39 ...
Page 41: ...41 ...
Page 44: ...44 ...
Page 59: ...10 10 10 10 R921 R924 R642 R544 R542 R610 R922 DSW1 DSW1 R923 R541 R543 100 59 ...
Page 77: ... 3 3 1 77 ...
Page 82: ...SELF DIAGNOSIS LIGHTING MODE MODEL RAC 25 A RAC 35 A FP FP 82 ...
Page 98: ...98 36 ...
Page 99: ...99 ...
Page 100: ...100 59 ...
Page 101: ...101 ...
Page 113: ...38 39 PARTS LIST AND DIAGRAM INDOOR UNIT MODEL RAF 25 35RPA 113 ...
Page 114: ...114 HWRAF 50NX2 A14 HBOARD AS ...
Page 117: ...RAF 25RPA RAC 25FPA RAF 35RPA RAC 35FPA HHAW NO 0069E 117 2 ...
