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Menu 5

Parameter

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Parameter

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Advanced parameter

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Performance RFC mode

130 Unidrive SP Advanced User Guide

www.controltechniques.com Issue Number: 10

The drive can include the effects of saturation by representing the flux producing current to flux characteristic as a series of three lines as shown

below:

If Pr 5.29 and Pr 5.30 have their default values of 50 and 75, the characteristic becomes one line and there will be a linear relationship between the

drive estimate of flux and the flux producing current. If Pr 5.29 and Pr 5.30 are increased above 50 and 75 the drive estimate of flux can include the

effect of saturation. It is unlikely that information will be available to set up these parameters, and so the values are determined during the rotating

auto-tune test.

This parameter controls the gain of the voltage controller used for mains loss and standard ramp control. If the parameter is set to 1 the gain used is

suitable for applications where the drive is used alone. Higher values are intended for applications where the DC bus of each drive is connected in

parallel and the drive is used as a master for mains loss control. This is intended for use in applications where each drive is locked together using

open-loop frequency slaving. (If motors are locked together using digital-locking, using a master for mains loss control, it is unlikely that the system

will be stable during mains loss unless the power rating of the master is much higher than the combined rating of the slaves. This is due to the lag

created by the master motor inertia).

This parameter shows the motor torque per amp of active (torque producing) current used to calculate the speed controller gains when the automatic

set-up methods are active (i.e. Pr 3.17 = 1 or 2).

Closed-loop vector

The drive calculates the motor torque per amp of active current using the motor parameters as shown below assuming a motor efficiency of 90%.

Rated active current is the active current when the motor current is equal to the rated motor current and is defined at the start of the description of

menu 4.

Servo

The motor torque per amp (Kt) must be entered in this parameter by the user for the automatic gain calculation system to operate correctly, and to

allow the drive to calculate the correct inertia during an inertia auto-tune.

5.31 Voltage controller gain

Drive modes Open-loop, Closed-loop vector, Servo

Coding