Spatial vector modulation method of indirect matrix converter

Abstract

the invention provides a spatial vector modulation method of an indirect matrix converter. The method comprises the following steps of determining a first duty cycle of a zero vector of an inversion stage, selecting a plurality of turning periods in a modulation period, wherein the total time length of the plurality of turning periods is the product of the first duty ratio and the modulation period, taking the starting time of each turning period as the modulation time for the switching states of the rectifying stage and the inversion stage in each turning period, adjusting all the switches ofthe rectifying stage to be disconnected at the starting moment of each turning period, remaining all the switching states of the inversion stage unchanged; namely, disconnecting all the switches of the rectification stage to realize the introduction of a zero vector into the inversion stage, in the modulation process of the indirect matrix converter in a time period when a zero vector originallyneeds to be led into to the inversion stage. The switch state at the initial moments of the time periods at the inversion stage does not need to be adjusted, so that the frequency of the action of theswitch of the inversion stage is reduced on the basis of reducing the common mode current. The loss of the system is reduced.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more specifically, relates to a space vector modulation method of an indirect matrix converter. Background technique [0002] The indirect matrix converter is a research hotspot in the field of power electronics in the past ten years. It has many excellent characteristics, such as bidirectional energy flow, sinusoidal input and output currents, controllable input power factor, and no need for intermediate large-capacity energy storage links. Wait. In addition, the indirect matrix converter also overcomes the shortcomings of the traditional matrix converter such as complex commutation control, so it has a wide range of applications in the fields of motor drive and wind power generation. [0003] However, matrix converters generate high frequency, high du / dt common-mode voltages at the neutral point of the motor load during operation. The common-mode voltage excites the stra...

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Problems solved by technology

At the same time, the common mode current will also cause corrosion and damage to the motor bearings, which will affect the life of the motor

[0004] At present, reducing the common-mode current of indirect matrix converters is generally achieved by suppressing the common-mode voltage. One is to flexibly adjust the switching state of the inverter stage to achieve zero vector to suppress the common-mode voltage. The other is to achieve it through two effective vectors. Zero vector to suppress the common mode voltage, but these two methods will cause too many switching actions of the inverter stage, resulting in increased system loss

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