Universal direct multi-level inverter three-dimensional space vector modulation algorithm

Abstract

The invention discloses a universal direct multi-level inverter three-dimensional space vector modulation algorithm. The algorithm is characterized in that three-phase reference voltages are normalized to be mapped to a three-dimensional rectangular coordinate system to obtain a reference voltage track curve directly, switch state vectors are mapped to the three-dimensional rectangular coordinate system to serve as the basic vectors of the three-dimensional rectangular coordinate system, and all the basic vectors are disposed at the vertexes of the cube. The reference voltage track curve are sampled to obtain reference vectors, the unit cube of the reference vectors is determined, four basic vectors are searched on the unit cube and are used for being combined into a reference vector, and the four basic vectors are switched among the four basic vectors along sides of the cube. By means of the algorithm, the problem that one basic vector has a plurality of redundancy switch state vectors of traditional multi-level inverters is solved, the reference vector location is simplified, and the algorithm is simple to implement and applicable to any multi-level inverters.

Description

technical field [0001] The invention relates to the technical field of space vector modulation of multilevel inverters, in particular to a general and direct three-dimensional space vector modulation algorithm of multilevel inverters. Background technique [0002] The space vector modulation algorithm has the advantages of high DC voltage utilization rate, low harmonic distortion rate, and easy digital realization, etc., and is widely used in the modulation of multilevel inverters. However, with the increase of the number of output levels of the multilevel inverter, the number of basic vectors and the number of switch state vectors are greatly increased during the implementation of the space vector modulation algorithm, and there are multiple switch state vectors in one basic vector ( That is, the redundant switch state vector), which leads to the difficulty in locating the basic vector of the equivalent reference vector, and the selection of the switch state vector correspo...

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Problems solved by technology

However, with the increase of the number of output levels of the multilevel inverter, the number of basic vectors and the number of switch state vectors are greatly increased during the implementation of the space vector modulation algorithm, and there are multiple switch state vectors in one basic vector ( That is, the redundant switch state vector), which leads to the difficulty in locating the basic vector of the equivalent reference vector, and the selection of the switch state vector corresponding to the appropriate basic vector is even more difficult, which ultimately restricts the use of the space vector modulation algorithm in multi-electric power systems with levels greater than seven. Applications on flat inverters

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