Vector control method, system and device for frequency converter

Abstract

The invention discloses a vector control method for a frequency converter, applied to the frequency converter that outputs electric energy to a motor through an LC output filter. The method comprisesthe following steps: obtaining an output current of the frequency converter; obtaining a compensation current value corresponding to the current of a filter capacitor according to the output current of the frequency converter, electrical parameters of the LC output filter, and the reference voltage of the frequency converter; obtaining a control parameter of the frequency converter according to the compensation current value; and controls the frequency converter by using the control parameter of the frequency converter. By using the compensation current value obtained by the output current ofthe frequency converter, the electrical parameters of the LC output filter and the reference voltage of the frequency converter, the control parameters of the frequency converter are obtained, therebycontrolling the frequency converter to output a relatively ideal current, adjusting the reactive current output by the frequency inverter, and reducing the output voltage of the inverter, so as to reduce the input current of the motor and reduce the loss of the motor. The application also discloses a vector control system and device for a frequency converter.

Description

technical field [0001] The invention relates to the technical field of electrical equipment control, in particular to a vector control method, system and device for a frequency converter. Background technique [0002] With the development of new energy technology, energy-saving technology, high-end equipment manufacturing and other technologies, the application of high-speed centrifuges and air compressors is becoming more and more extensive, and the requirements for the output frequency of inverters are getting higher and higher. However, the frequency converter is limited by the switching frequency of the power module. When the output power is used to directly drive the motor, the harmonics of the motor current are very large, and the motor generates serious heat, which seriously affects the performance and service life of the motor. [0003] In order to reduce the current harmonics of the motor, an LC output filter is usually connected in series between the inverter and t...

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Problems solved by technology

On the one hand, the voltage drop of the current on the inductor is too large, which affects the utilization rate of the bus voltage, and the output voltage of the inverter needs to be increased to compensate for the influence of the voltage drop on the inductor; on the other hand, the reactive current on the filter capacitor is injected into the motor In the winding, the input current of the motor increases, the power factor decreases, the loss of the motor increases, and the heat generation not only does not decrease due to the reduction of harmonics, but increases

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