Space vector pulse width modulation method for multi-level inverter

Abstract

The invention discloses a space vector pulse width modulation method for a multi-level inverter. According to the modulation method, a region which a space vector is located at a complex plane is judged through a given three-phase voltage, different coordinate systems are selected when the space vector is located at different regions on the complex plane, a basic vector for synthesis of the space vector and the action time of the basic vector are determined, and the basic vector is in correspondence to an output state of the three-phase voltage type multi-level inverter. Compared with the traditional modulation method, the modulation method has the advantages that the all switching states corresponding to a certain basic vector can be determined by simple operation, the action time of the basic vector is easy to calculate, a large number of trigonometric function and anti-trigonometric function operation is avoided, the operation of coordinate transformation is reduced, and digital implementation is promoted.

Description

technical field [0001] The invention relates to a three-level and above three-level voltage type multilevel inverter modulation method, in particular to a three-phase voltage type multilevel inverter space vector pulse width modulation method. Background technique [0002] Space voltage vector pulse width modulation regards the inverter and the motor as one, starting from the overall output effect of the three-phase voltage, the output voltage of the three-phase inverter is synthesized into a space voltage vector on the complex plane, and through different basic vector combinations To approach the specified space voltage vector, so that the output voltage waveform is as close as possible to the ideal sinusoidal waveform. [0003] At present, researchers at home and abroad have proposed different modulation methods for the basic principles of space vector pulse width modulation. The commonly used methods are (1) Cartesian coordinate system modulation method; (2) 60° coordinat...

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Problems solved by technology

[0005] The 60° coordinate system modulation method expresses the space vector and the basic vector in the 60° coordinate system, and then calculates the basic vector used for the equivalent space vector and the action time of the basic vector, and determines the three-phase voltage type multilevel inverter. Output state, this modulation method also needs to divide the plane into 6 areas to discuss separately. Compared with the Cartesian coordinate system modulation method, the calculation is simplified, but it still needs to perform trigonometric and inverse trigonometric operations and coordinate transformation

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