A harmonic suppression method for vienna rectifier

Abstract

The invention discloses a harmonic suppression method of a VIENNA rectifier. The waveform sine degree and ripple size of the input current of the VIENNA rectifier affect the harmonic distortion rate, and the VIENNA rectifier undergoes current tracking control and voltage modulation to obtain an input current with a low distortion rate , the harmonic suppression method includes: current tracking control using a nonlinear controller to reduce the current tracking error; using a five-segment and seven-segment hybrid space voltage vector modulation method to eliminate distortion at the zero-crossing point of the input current, and the modulation voltage The rate of change is used as a pulsating modulation frequency parameter to form a periodic variable switching frequency modulation, thereby reducing the input current ripple; the present invention adopts nonlinear current tracking control, five-stage and seven-stage hybrid modulation, and variable The method of frequency modulation is combined to eliminate current distortion, reduce current ripple, and suppress current harmonics.

Description

technical field [0001] The invention relates to the technical field of harmonic suppression, in particular to a harmonic suppression method of a VIENNA rectifier. Background technique [0002] The typical feature of VIENNA rectifier is the use of bidirectional switches to form a circuit topology with unidirectional current flow. The sine and ripple of the input current waveform of the VIENNA rectifier will affect the current harmonic distortion rate. The harmonic distortion rate reflects the operation of the rectifier in the power grid. performance indicators. The input current quality and power utilization of VIENNA rectifier are related to the current tracking control method and the voltage modulation technology. [0003] Among them, the reasons for the ripple of VIENNA rectifier and the reasons for affecting the current quality are as follows: the change rate of the inductor current is proportional to the voltage across the inductor, and the difference between the modula...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a harmonic suppression method for VIENN rectifiers to solve the problem that the five-segment and fixed-frequency PWM modulation methods in the prior art will increase the input current ripple, and the fixed virtual damping will easily lead to an increase in the PWM modulation ratio. The phenomenon of over-modulation occurs, which causes the current tracking error to further increase and affects the technical problem of system stability.

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