AirStage AO54FJ, Service Manual

Page: 41 / 169

3-1-3 Basic Circuit of 3 phase Inverter
S1
S2
S3
S4
S5
S6
U – V
V – W
W – U
time
ON
OFF
S1
By changing the ON-OFF cycle of the switch, the By changing the ON-OFF cycle of the switch, the
rotation of the motor can be varied at the desired rotation of the motor can be varied at the desired
frequency. If the DC voltage is changed, the input frequency. If the DC voltage is changed, the input
voltage of the motor can be also varied. voltage of the motor can be also varied.
Practically, the motor is rotated by using 6pcs Practically, the motor is rotated by using 6pcs
of transistors instead of a switch, and the transistor of transistors instead of a switch, and the transistor
is alternately turned ON-OFF. is alternately turned ON-OFF.
MOTOR
P
N
3-1-4 PWM Control
AC Inverter
PWM Control System
The motor needs a sign wave input. The pulse width of the DC
voltage from the converter is varied and cut out by the switching at
the inverter as shown in the figure, and the motor rotation is
controlled by the quasi-sign wave that is created by varying it to the
desired average voltage.
DC Inverter
PWM Control System
By using a brush less motor, the DC voltage pulse width from
the converter is varied and cut out by the switching of the
inverter, and the DC motor rotation is controlled by varying it to
the desired average voltage
It differs from AC compressor and
the pulse becomes the equal interval waveform
PAM Control System
By using a brush less motor, the motor rotation is controlled by
applying a variable voltage of DC140V through 390V to the
motor winding directly with the voltage booster which is
composed of a reactor and a switching component.
S4
S3
S6
S5
S2
U
V
W
03-02