Controlling method for three-phase voltage type grid inverter

Abstract

The invention discloses a digital controlling method of a three-phase voltage type grid inverter. The controlling method for the three-phase voltage grid inverter is based on the thought of a traditional dead beat technology, and comprises the steps of voltage predication, current predication, dead-time compensation and zero-sequence current injection improvement. The controlling method for the three-phase voltage grid inverter solves the problem that digital achievement of traditional dead-time controlling is poor in stability and tracing accuracy, wherein the problem is caused by the sampling channel and the delay of the calculation process and 'one-step-delay' control.

Description

technical field [0001] The invention relates to the technical field of power electronic converters, in particular to the control technology of three-phase voltage type grid-connected converters. Background technique [0002] With the development of power electronics technology and distributed energy application technology, grid-connected converters, as the basic interface unit for distributed energy grid-connected, have broad application prospects. There are many kinds of grid-connected converters and their control methods. In order to meet the requirements of power quality, voltage-type converters have become the mainstream. Among the control methods of voltage-type grid-connected converters, most of them adopt double closed-loop direct current control technology. , has the advantages of good tracking effect and no static error. [0003] The deadbeat current control technology is one of many current control technologies. It has the outstanding advantages of convenient digi...

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Problems solved by technology

[0004] The present invention is based on the digital control technology of the converter, and aims at the problems of low-frequency oscillation of 1 / 6 switching frequency and decreased tracking accuracy caused by the delay of the sampling channel and the control process during the specific implementation process of the traditional deadbeat control , put forward an improved algorithm to improve stability and control accuracy, combined with a pulse modulation method suitable for deadbeat control and dead zone compensation technology, applied to three-phase voltage-type grid-connected converters (including PWM rectifier and PWM inverter), which overcomes the stability and control accuracy problems of traditional deadbeat control in digital implementation, and improves the utilization rate of DC bus voltage, improves the grid-connected current waveform, and improves the power quality

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