Control method of frequency converter without feedback of current transformer

Abstract

The invention discloses a frequency converter control method without adopting current transformer feedback, and relates to the technical field of frequency conversion control, and the method comprisesthe following steps: S1, removing a current transformer from a frequency converter control line, and guaranteeing that a system has no hardware fault; S2, adjusting the control mode of the frequencyconverter into current open-loop control; S3, selecting a lifting mode of the frequency converter as a current lifting mode; S4, starting automatic parameter setting of the frequency converter, and meanwhile, automatically setting reference values of the current, the voltage, the frequency, the rotating speed and the torque of the load motor as rated values of the motor; S5, selecting and settingan output filter of the frequency converter as a filter; S6, adjusting the current modulation depth of the frequency converter, and limiting the maximum output current of the electric frequency converter; accurate control of the motor speed of the frequency converter under the control of the current-free transformer is achieved.

Description

technical field [0001] The invention relates to the technical field of frequency conversion control, in particular to a control method of a frequency converter that does not use current transformer feedback. Background technique [0002] Due to the high requirements on the running accuracy of the on-site roller motor, it is necessary to have fast response ability and instantaneous large torque output, and no large current and over temperature. Therefore, at the beginning of the design, the control method of the frequency converter is designed to have current transformer feedback. The actual current and participate in the current closed-loop control of the precise control of the inverter. A current inductor is set at the outlet end of the inverter, which is used to measure the actual output current of the inverter in real time, compare it with the calculated and set current of the inverter, and then adjust the actual current of the motor during operation in real time, so as t...

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Problems solved by technology

[0003] Changing the inverter control mode directly to open-loop current control can temporarily resume production. However, using the inverter current open-loop method for control, it is found in actual experiments that due to the high dynamic requirements of field equipment under current open-loop control, rapid acceleration And rapid deceleration will cause instantaneous over-current alarm shutdown. When the roller table motor runs under current open-loop control, the overall current is too large, which is close to the over-current threshold. If the site load changes slightly, an over-current alarm may occur, and due to damage If the current sensor is not replaced, the hardware failure will still be reported, and the operation of the inverter is extremely unstable.

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