Bosch Rexroth IndraDrive MPH-02 Functional Description page 228

6-16
Drive Control
Flux Model
Voltage Loop
In addition, magnetization can be influenced via bit 2 of P-0-0045,
Control word of current controller:
•
With bit 2 = 0 in P-0-0045 (default) magnetization is increased up to
the nominal value according to the required torque; 100% are
reached at nominal motor torque.
•
With bit 2 = 1 in P-0-0045 magnetization remains at the value set in
P-0-0532 independent of the load.
The flux feedforward calculates the optimum rotor flux command value for
each working point of the machine. The limiting variable is the motor
voltage that increases with the speed. As limit value the flux feedforward
uses the value in parameter P-0-0535, Motor voltage at no load. The
motor voltage at no load is specified in a percentage-based way and also
refers to the maximum possible output voltage of the inverter.
Note: A setting of 80% in parameter P-0-0535 is advisable.
In addition, the following motor data have an influence on flux feedforward
and flux model:
• P-0-4004, Magnetizing current
• P-0-4039, Stator leakage inductance
• P-0-4040, Rotor leakage inductance
• P-0-4041, Motor magnetizing inductance
• P-0-4042, Characteristic of motor magnetizing inductance
• P-0-4043, Rotor time constant
On the basis of the above motor data and the active value of the flux-
generating current I , the flux model calculates the actual value of the
d
rotor flux. This value is used as actual value for the flux loop (see below)
and additionally determines the torque constants and the behavior of the
slip frequency of the asynchronous machine required for generating the
torque.
The slip frequency changes with the temperature of the motor. This is
compensated by measuring the motor temperature (S-0-0383) and
evaluation with the factor in parameter
• P-0-0530, Slip increase.
This factor is to set depending on the motor cooling type.
The voltage loop works as a PI loop and in the absolute value limits the
voltage output by the current loop to a maximum value. The setting is
made via the following parameters:
• P-0-0533, Voltage loop proportional gain
• P-0-0534, Voltage loop integral action time
• P-0-0536, Maximum motor voltage
When the maximum motor voltage is exceeded, the output of the voltage
loop interferes in a corrective way in the output value of the flux feed
forward.
The maximum motor voltage is specified in a percentage-based way and
refers to the maximum possible output voltage of the inverter that is
determined by the active DC bus voltage (cf. S-0-0380).
Note: A setting of 90% in parameter P-0-0536 is advisable.
MPH-02, MPB-02, MPD-02
DOK-INDRV*-MP*-02VRS**-FK01-EN-P