Справочник Пользователя для Mitsubishi Electronics FR-V540-1.5K to 55K

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Vector control is one of the control techniques for driving an induction motor. To help explain vector control, the 
fundamental equivalent circuit of an induction motor is shown below: 

In the above diagram, currents flowing in the induction motor can be classified into a current id (excitation current) 
for making a magnetic flux in the motor and a current iq (torque current) for causing the motor to develop a torque.
.

Motor-generated torque (TM), slip angular velocity (

ωs) and the motor's secondary magnetic flux (φ2) can be found 

by the following calculation:

r1 : Primary resistance
r2 : Secondary resistance

1

: Primary leakage inductance

2

: Secondary leakage inductance

M : Mutual inductance
S :  Slip
id : Excitation current
iq : Torque current
im : Motor current

In vector control, the voltage and output frequency are 
calculated to control the motor so that the excitation 
current and torque current (as shown in the left figure) 
flow to the optimum as described below:

(1) The excitation current is controlled to place the 

internal magnetic flux of the motor in the optimum 
status.

(2) Derive the torque command value so that the 

difference between the motor speed command and 
the actual speed obtained from the encoder 
connected to the motor shaft is zero. Torque current 
is controlled so that torque as set in the torque 
command is developed.

T

M

 

∝ φ

2 

⋅ iq

φ

2

 

= M ⋅ id

ωs = 

where, L2 = secondary inductance
L2 =

2 

+ M

Vector control provides the following advantages:

(1) Excellent control characteristics when compared to 

V/F control and other control techniques, achieving 
the control characteristics equal to those of DC 
machines.

(2) Applicable to fast response applications with which 

induction motors were previously regarded as 
difficult to use. Applications requiring a wide 
variable-speed range from extremely low speed to 
high speed, frequent acceleration/deceleration 
operations, continuous four-quadrant operations etc.

(3) Allows torque control.

(4) Allows servo-lock torque control which generates a 

torque at zero speed (i.e. status of motor shaft = 
stopped).

1

im

r

1

r

2

S

M

id

iq

2

tor

q

ue

 cu

rr

ent

 

iq

motor current   im

excitation current

id

L2

r2

id

iq