Method for modulating space vector impulse width of frequency converter

Abstract

The invention provides a method for modulating the space vector impulse width of a frequency converter. The method comprises the following steps of: A, sampling the three-phase current of an electric motor by the frequency converter, and performing coordinate conversion on the current from three phases to two phases; B, calculating a current vector angle according to a current value under a two-phase coordinate system; C, determining a space vector conversion angle through the current vector angle and a power factor angle; and D, generating a modulating signal of the space vector impulse width. The deal zone influence of five-segment type SVPWM (Space Vector Pulse Width Modulation) during the conversion process is balanced through correlation of the power factor angle and the space vector conversion angle, so that the problem of current waveform distortion is solved. The method effectively eliminates the current waveform distortion of the five-segment type SVPWM at the moment of conversion, and has good effect in practical application. The method has novel effectiveness, and is technical innovation of frequency converters during application process.

Description

technical field [0001] The invention relates to the technical field of frequency converter control, in particular, the invention relates to a method for space vector pulse width modulation of a frequency converter. Background technique [0002] The modulation method of the frequency converter mostly uses space vector pulse width modulation - SVPWM. Among them, the five-segment SVPWM modulation method is widely used in the inverter system because of its small switching loss and high voltage utilization rate. In the process of using the five-segment SVPWM modulation, in order to balance the upper and lower bridge arms, different zero vectors need to be inserted in the same sector, but in this mode, the impact of the dead time is different. This effect results in distorted jumps in the voltage waveform and at the same time distorts the current waveform. Although the zero-point clamping phenomenon can be effectively compensated by the dead zone compensation, the effect of the ...

AI Technical Summary

Problems solved by technology

[0017] The technical problem to be solved by the present invention is to provide a method for space vector pulse width modulation of a frequency converter, which can balance the influence of the dead zone of the five-stage SVPWM in the switching process through the correlation between the power factor angle and the space vector switching angle, and solve the problem of Current Waveform Distortion Problem

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