Modulation method and device for current-source inverter

Abstract

The invention provides a modulation method and device for a current-source inverter. The method comprises the following steps: acquiring a three-phase symmetric reference signal, and carrying out Clark transformation on the three-phase symmetric reference signal, thus obtaining a first sine signal and a second sine signal; carrying out vectorial combination on the first sine signal and the second sine signal, thus obtaining a vectorial combination signal; judging a sector where the vectorial combination signal is located, and if the vectorial combination signal is located in a first sector, calculating bridge arm on-off state time of the first sector; distributing carrier periodic time according to a sequence, and obtaining multiple state change time according to the bridge arm on-off state time of the first sector; carrying out carrier modulation on the multiple state change time, and carrying out on-off vector configuration, thus generating a triggering pulse signal. According to the modulation method for the current-source inverter, an optimal waveform is output according to the distribution of the time sequence, and the number of on-off times and the on-off loss under a voltage reduction mode are the minimum.

Description

technical field [0001] The invention relates to the technical field of inverters, in particular to a modulation method and device for a current-type inverter. Background technique [0002] With the continuous improvement of industrialization and automation level, more and more power electronic inverters are used in various fields. Common inverters include current-mode Trans-Z source inverters and current-mode Trans-Z source inverters. The working process includes 3 working states: short-circuit state, open-circuit state and active state, and each carrier cycle T PWM Including short circuit time t 0 , open circuit time t op and effective state time t 1 , t 2 . The SVPWM (Space Vector Pulse Width Modulation, Space Vector Pulse Width Modulation) of the current mode Trans-Z source inverter includes a symmetrical sequence and an asymmetrical sequence. [0003] The asymmetric sequence is a carrier period T PWM Short circuit time t 0 , open circuit time t op and effective ...

AI Technical Summary

Problems solved by technology

In a symmetric series, for example, the time series t 0 -t op -t 1 -t 2 -2t 0 -t 2 -t 1 -t op -t 0 , it switches 5 times in one carrier cycle, that is, the switching frequency is 5f PWM , where f PWM is the carrier frequency, through the above modulation method, the effective value of the current in one carrier cycle can be made to be the current effective value that needs to be synthesized. However, in this modulation method, the inverter output current of the asymmetric sequence has large distortion and high harmonic content.

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