Efficient Networks S120 manual Sensorless operation without an encoder, Parameter overview

Servo control

3.11 Sensorless operation (without an encoder)

Example of measuring the speed controller frequency response

By measuring the speed controller frequency response and the control system, critical resonance frequencies can, if necessary, be determined at the stability limit of the speed control loop and dampened using one or more current setpoint filters. This normally enables the proportional gain to be increased (e.g. Kp_n = 3* default value).

After the Kp_n value has been set, the ideal integral action time Tn_n (e.g. reduced from 10 ms to 5 ms) can be determined.

Example of speed setpoint step change

A rectangular step change can be applied to the speed setpoint via the speed setpoint step change measuring function. The measuring function has preselected the measurement for the speed setpoint and the torque-generating current.

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Figure 3-16 Setting the proportional gain Kp

Parameter overview

See "Speed controller".

3.11Sensorless operation (without an encoder)

NOTICE

The operation of synchronous motors without an encoder must be verified in a test application. Stable operation in this mode cannot be guaranteed for every application. Therefore, the user will be solely responsible for the use of this operating mode.

Description

This allows operation without an encoder and mixed operation (with/without encoder). Encoderless operation with the motor model allows a higher dynamic response and greater stability than a standard drive with V/f control. Compared with drives with an encoder, however, speed accuracy is lower and the dynamic response and smooth running characteristics deteriorate.

88	Drive Functions
	Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4