Five-phase inverter model prediction current control method based on duty ratio optimization

Abstract

The invention discloses a five-phase inverter model prediction current control method based on duty ratio optimization. The method specifically comprises the steps of selecting four adjacent large vectors of an alpha-beta subspace to synthesize a virtual voltage vector according to a specific duty ratio, and eliminating the harmonic voltage of an x-y subspace; selecting the virtual voltage vectorto construct a finite control set, and simplifying a prediction model and an evaluation function; estimating the action time of the virtual voltage vector in each control period, optimizing the duty ratio, and reducing current ripples; selecting two large vectors in opposite directions to be combined according to the same duty ratio, the volt-second value of each control period is adjusted, and therefore common-mode voltage is restrained; and designing and optimizing a switch sequence, and realizing average switching action times of each bridge arm. According to the invention, the common-modevoltage is reduced by 80% while the low-order harmonic current is effectively suppressed; and the evaluation function is simplified, the current tracking precision is improved, and the current ripplesare reduced.

Description

technical field [0001] The invention belongs to the field of design and manufacture of a five-phase motor AC control system in the field of power electronics and electric transmission, and in particular relates to a five-phase inverter model prediction current control method based on duty cycle optimization. Background technique [0002] Model predictive control has the advantages of simple and flexible control, low switching frequency and multi-objective optimization. One of the commonly used methods in the field, this method directly controls the current, the concept is intuitive and the implementation is simple, and it has become a research hotspot in the field of motor control. The classic FCS-MPCC estimates the current change trend at the next moment in each control cycle, selects the optimal vector according to the evaluation function, and applies the optimal vector to the next control cycle. However, most of the time, the error between the actual current and the refe...

AI Technical Summary

Problems solved by technology

However, the introduction of common-mode voltage constraints and the adjustment of weight coefficients make the algorithm complex, especially in the five-phase system, it is also necessary to consider the constraints of harmonic currents, and the adjustment of weight coefficients is more difficult

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