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CHAPTER 1 CONTROLLER
CHAPTER 1 CONTROLLER
9. 9.
AC M M ot otor or Sy
AC
9 9 . . 1 1
F F e e a a t t u u r r e e o o f f A A C C m m o o t t o o r r
The AC motor model trucks covered by this manual use AC motors (three-phase induction motors) as the traction motor and
The AC motor model trucks covered by this manual use AC motors (three-phase induction motors) as the traction motor and
pump motor. AC motors have the following advantages over DC motors:
pump motor. AC motors have the following advantages over DC motors:
(1) AC motor
(1)
AC motors are simple
maintenance is significantly reduced.
maintenance is significantly reduced.
(2) AC moto
(2)
AC motors are com
(3) An AC motor
(3)
An AC motor of a certain siz
9. 9.2 2
Sp
Spee
Speed control of DC motors depends on regulation of the
Speed control of DC motors depends on regulation of the
field and armature current amounts, while that of AC motors
field and armature current amounts, while that of AC
basically depends on adjustment of the frequency of the
basically depends on adjustment of the frequency of the
alternating current power supply. The speed of an AC
alternating current power supply. The speed of an AC motor
is determined by the frequency of the power supply AC
is determined by the frequency of the power supply AC
current and the load on the
current and the load on the motor.
In addition, the voltage and current to the motor must be
In addition, the voltage and current to the motor must be
controlled properly so that the motor operates in its
controlled properly so that the motor operates in its
optimum characteristic range. (Fig. 1)
optimum characteristic range. (Fig. 1)
The frequency and voltage can be controlled in a variety of
The frequency and voltage can be controlled in a
methods including the "vector control method" employed
methods including the "vector control method" employed
in the AC motor model trucks. This method provides highly
in the AC
motor model trucks. This method provides highly
responsive control according to ever changing truck-
responsive control according to ever changing truck-
operating conditions through a high-speed calculation of
operating conditions through a high-speed calculation of
huge amount of data. The vector control calculation is
huge amount of data. The vector control calculation is
performed by the inverter. (Fig. 2)
performed by the inverter. (Fig. 2)
F
F
N
N
R
R
Syst ste e m B
m Ba a si sic c s s
s are simple in construction.
in construction. Since they d
rs are compatib
patible with hig
le with high-spe
h-speed oper
of a certain size produces
e produces higher power
eed co
d cont ntro rol of
l of in indu
duct ctio ion m
motor.
Logic unit
Logic unit
Torque
To
Calculation
Calculation
order
order
Accelerator
Accelerator
for required
for required
output
output
Brake
Brake
Since they do not have
o not have friction par
ed operatio
ation. n.
higher power than a DC moto
than a DC motor of the same
n mot otor ors s
motors
motor
Low-speed operation
Low-speed operation
variety of
(low frequency)
(low frequency)
Gate
Gate
driving
driving
pulse
pulse
rque
Vector control
Vector control
calculation
calculation
Truck
Truck
speed
speed
Current
Current
(Fig. 2)
(Fig. 2)
friction parts like brushes
ts like brushes and commu
and commutators, daily
r of the same size.
size.
U
U
V
V
Inverter
Inverter
W
W
V
V
V
V
U
U
V
V
W
W
t
t
High-speed operation
High-speed operation
(Fig. 1)
(Fig. 1)
Inverter
Inverter
MOS-FET modules
MOS-FET modules
1-71
1-71
tators, daily
IM
IM
t
t
500965
500965
IM
IM
Speed
Speed
500966
500966
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