A Space Vector Modulation Method for Multi-source Converter

Abstract

The invention provides a space vector modulation method of a multi-source converter and belongs to the technical field of pulse width modulation of a multi-source converter. Including combining the per unitized Cartesian coordinate system to construct the neutral point potential unbalanced space vector model; dividing the small vectors into vector group 1 and vector group 2, and determining the small sectors formed by the small vectors in vector group 1 and vector group 2 The boundary equation of the small sector; according to the boundary equation of the small sector, determine the reference voltage vector; calculate the action time ratio of the basic vector of the small sector; according to the action time ratio, the vector group 1 and the vector group 2 are mixed and modulated to realize DC Side power distribution to obtain multiple energy flow modes. The present invention adopts the method based on the coordinate operation to solve the problem caused by the unbalanced voltage of the midpoint, and reduces the calculation amount; adopts the mixed modulation of the vector group 1 and the vector group 2, and controls the action time weight of the vector group 1 and the vector group 2, The power distribution on the DC side is realized, and more energy flow modes are obtained.

Description

technical field [0001] The invention relates to the technical field of pulse width modulation of multi-source converters, in particular to a space vector modulation method of multi-source converters. Background technique [0002] Space Vector Pulse Width Modulation (SVPWM) is a modulation technology that controls the converter based on the space voltage (current) vector switching of the converter. The ideal flux circle of the stator of the relative symmetry motor is used as the reference standard, and different switching modes of the converter are used to switch the space voltage vector, and the actual magnetic flux generated is to approach the reference circular magnetic flux, and the switching of the converter is determined by the result of their comparison. Form PWM waveform. Compared with the direct SPWM technology, its main advantages include a higher degree of harmonic optimization, improved voltage utilization and dynamic response speed of the motor, and is suitable ...

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Problems solved by technology

[0004] However, the fixed three or four working modes of the current SVPWM algorithm limit more energy flow modes between the DC side energy source and the motor, and the two-level output phase voltage obtained on the AC side has lower harmonic performance than multi-level ones. Poor, and did not propose a solution to the problem of midpoint potential imbalance, using the combination of trigonometric functions to calculate the space vector action time increases the amount of calculation

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