Space vector modulation method of four-leg converter based on classification algorithm and apparatus thereof

Abstract

A space vector modulation method of a four-leg converter based on a classification algorithm and an apparatus thereof belong to a four-leg converter vector modulation method. The method comprises the following steps: 1. Using three phase reference voltages vref1, vref2 and vref3 to calculate six intermediate variables nI, acquiring a maximum intermediate variable nI and a secondly maximum intermediate variable nI through a comparison network so as to determine a triangular prism where a reference voltage space vector Vref is located; 2. Carrying out clark transformation on an input signal and determining a located tetrahedron through a relation between the reference voltage space vector Vref and five planes in the triangular prism; 3. Defining n0 and calculating action time t1, t2, t3 of three adjacent basic voltage space vectors V1,V2 and V3 through linear combination with the maximum intermediate variable nI and a secondly maximum intermediate variable nI in the step 1; 4. According to above results, switching a switching device of the converter so that an output voltage of the four-leg converter is equivalent with a reference voltage. An algorithm realization process is simplified and comprises: calculating the intermediate variables; determining a maximum value and a secondly maximum value of the intermediate variables; carrying out the linear combination on the intermediate variables. The steps are intelligible. The realization is simple. Computation of the algorithm is small and real-time performance is strong.

Description

technical field [0001] The invention relates to a vector modulation method and device for a four-leg converter, in particular to a space vector modulation method and device for a four-leg converter based on a classification algorithm. Background technique [0002] The four-leg converter uses the fourth leg to control the neutral current, deal with unbalance and linear distortion problems. Voltage space vector modulation is a method widely used at present. The English abbreviation of voltage space vector modulation is SVPWM. From the perspective of the motor, it focuses on how to make the motor obtain a circular rotating magnetic field with constant amplitude, that is, sinusoidal flux. Since the SVPWM base vector of the four-leg converter is three-dimensional in space, it is also called three-dimensional voltage space vector modulation when applied to the four-leg SVPWM. The English abbreviation of three-dimensional voltage space vector modulation is 3D-SVPWM. [0003] SVPWM...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a space vector modulation method based on the classification algorithm four-leg converter, to solve the problem that the traditional three-dimensional voltage space vector modulation method needs more calculations, the calculation efficiency is low, and the real-time control is affected

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