Simplified multilevel space vector pulse width modulation method and space vector pulse width modulation soft core applicable to three-phase cascaded H-bridge converter

Abstract

The invention discloses a simplified multilevel space vector pulse width modulation method and a space vector pulse width modulation soft core applicable to a three-phase cascaded H-bridge converter. The method includes: firstly, at the starting moment of each switching period Ts, sampling a reference space voltage vector to obtain a corresponding reference space voltage vector of each unit; then, completing sector judgment on the reference space voltage vectors , and respectively by the aid of shared computing resources, rotating the corresponding reference space voltage vectors to a first sector to obtain , and , computing an actual sector N in which switching time is mapped to the reference space voltage vectors; finally, distributing the corresponding switching time of each unit by means of multichannel signal selection and completing corresponding PWM (pulse width modulation) signal generation of each unit. The method can be used for achieving modulation of the three-phase cascaded H-bridge converter, is easy to achieve balanced energy distribution of each power unit, good in harmonic characteristic, high in extendibility, low in computation complexity, easy in digitization implementation and good in dynamic and steady-state performance, and is applicable to simplified multilevel space vector pulse width modulation of a high-voltage high-power speed regulating system, a high-voltage direct-current power transmission system and an electric railway traction power supply system.

Description

technical field [0001] The invention relates to the design and manufacture fields of a high-voltage and high-power speed regulation system, a high-voltage direct current transmission system, an electrified railway traction power supply system, and a high-power static var generator. Background technique [0002] In recent years, multilevel converters have received extensive attention in high-voltage and high-power applications due to their unique structural characteristics. At present, the common voltage source multilevel converters can be roughly divided into two categories: clamp type and cell cascade type. With the increase of the number of levels, the former requires a sharp increase in the number of switching devices and is not conducive to modularization, integration and expansion, so that it is limited in practical applications, while the cascaded H-bridge multilevel converter (cascaded H-bridge multilevel converter, CHMC) has been widely used in various fields due to...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a simplified multi-level SVPWM method suitable for high-power three-phase cascaded H-bridge converters. In the traditional multi-level SVPWM method, the DC side voltage utilization rate is high, and it is easy to implement digitally. Under the premise, it is used to overcome the shortcomings of the traditional multi-level SVPWM method, which is not easy to balance the energy distribution of each power unit, poor scalability, high modulation calculation complexity, and large modulation system chip resource occupation.

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