6-14
Drive Control
MPH-02, MPB-02, MPD-02
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
-
-
-
-
S-0-0040
voltage
loop
P-0-4005
P-0-4045
P-0-4046
P-0-0043
S-0-0107
S-0-0106
S-0-0107
S-0-0106
P-0-0063
P-0-0044
P-0-0064
P-0-0065
ï
U
act
ï
S-0-0101
S-0-0100
P-0-0038
P-0-0039
DF000127v01_en.fh7
n
act
I
d_cmd
current
limitation
I
q_act
I
d_act
I
q-loop
I
d-loop
U
q_act
U
d_act
P-0-0048
P-0-0536
velocity
loop
I
q_cmd
P-0-0534
P-0-0533
I
d_cmd
1)
I
q_cmd
1)
n
cmd
1):
current command value after limitation
Fig. 6-13:
Simplified schematic diagram of the current control loop for a
synchronous machine (incl. voltage loop)
For field (or voltage) control a voltage loop designed as a PI loop is used
that can be set via the following parameters:
•
P-0-0533, Voltage loop proportional gain
•
P-0-0534, Voltage loop integral action time
Note:
The command value of the voltage loop is preset by parameter
P-0-0536, Maximum motor voltage
.
The voltage loop becomes active when the current loop output exceeds a
defined absolute voltage value (cf.
P-0-0536, Maximum motor voltage
).
By generating a field counteracting the permanent field-linked direct-axis
flux (
→
negative I
d
command value) a reduction of the output voltage can
be obtained.
Note:
The output value of the voltage loop is the command value for
the field-generating component of the subsequent current loop
(see figure above).
In the case of synchronous motors with field weakening, a command
value of I
d_cmd
= 0 is run in the base speed range, as in the case of
synchronous motors without field weakening.
When entering the field weakening, I
d_cmd
is increased towards negative
values and therefore allows higher motor velocities.
Closed-loop control of synchronous motors with reluctance torque, i.e.
motors with significantly different inductances in the d and q axes,
requires the separate input of L
d
and L
q
in the respective parameters:
•
P-0-4016, Direct-axis inductance of motor
(L
d
)
•
P-0-4017, Quadrature-axis inductance of motor
(L
q
)
Voltage Loop for Synchronous
Motors
Field Weakening of
Synchronous Motors
Closed-Loop Control of
Synchronous Motors with
Distinctive Reluctance Torque
Courtesy
of
CMA/Flodyne/Hydradyne
▪
Motion
Control
▪
Hydraulic
▪
Pneumatic
▪
Electrical
▪
Mechanical
▪
(800)
426-5480
▪
www.cmafh.com
