V/f characteristic control for asynchronous motor (VFC closed loop)

The V/f characteristic control with feedback (VFC closed loop) can be used if an
asynchronous motor with motor encoder is connected to the inverter.

The speed feedback leads to the
following advantages:

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Stationary speed accuracy

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Improved dynamics compared to the V/f characteristic control without feedback (VFC open loop) and to the encoderless vector control (SLVC)

Preconditions

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The V/f characteristic control (VFC closed loop) is only suitable for asynchronous motors.

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The V/f characteristic control (VFC closed loop) requires a feedback of the speed. A motor encoder must be connected to the inverter and set as feedback system for the motor control.

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This setting is not made automatically if a motor is selected from the motor catalog.

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For required settings see chapter "HTL encoder".

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If you actuate a drive with a square-law V/f characteristic: check whether the corresponding drive is suitable for operation with
a square-law V/f characteristic!

–

From the motor nameplate data, at least the rated speed and rated frequency must be entered, so that the inverter can calculate the correct
number of pole pairs.

Motor data

NOTICE

Motor damage!

Operating the motor above the rated motor frequency/rated voltage will lead to damage to the motor.

▶

Only operate above the rated motor frequency / rated voltage with the permission of the motor manufacturer.

Details

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0x2B00 (P302.00) provides different characteristic shapes.

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Limiting factors for the V/f characteristic are the rated mains voltage 0x2540:001 (P208.01), the minimum frequency 0x2915 (P210.00) and the maximum frequency 0x2916 (P211.00).

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The slip compensation is deactivated in this motor control type. In case of V/f characteristic control with feedback, the slip is calculated and injected by the slip controller.

Slip controller

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For more details, see the description of the motor control type:

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"V/f characteristic control for asynchronous motor (VFC open loop)"

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"Set voltage boost"