A Space Vector Modulation Method for Indirect Matrix Converter

Abstract

The invention provides a space vector modulation method of an indirect matrix converter, comprising: determining the first duty ratio of the zero vector of the inverter stage, selecting several switching periods in the modulation period, and the total duration of the several switching periods is the first duty cycle The product of the empty ratio and the modulation cycle, the initial moment of each switching period is used as the modulation moment for the switch state of the rectifier stage and the inverter stage in each switching period, at the beginning of each switching period, the rectification stage All the switches of the inverter are adjusted to be off, and the state of all the switches of the inverter stage is kept unchanged; that is, in the modulation process of the indirect matrix converter, the rectifier stage All the switches of the inverter are turned off to realize the introduction of zero vector to the inverter stage, and the inverter stage does not need to adjust the switch state at the beginning of these periods, thereby reducing the switch of the inverter stage on the basis of reducing the common mode current. The number of actions reduces the loss of the system.

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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