SVPWM (Space Vector Pulse Width Modulation) method suitable for line voltage cascade type triple converter

Abstract

The invention relates to an SVPWM (Space Vector Pulse Width Modulation) method suitable for a line voltage cascade type triple converter. According to the method, the three units of the line voltage cascade type triple converter are considered as an integrated body; switches are combined into corresponding equivalent circuits; the positions of switch combinations in a vector space are obtained according to the equivalent circuits; and valid switch combinations are selected to form a multi-redundant state three-level vector space. The method of the invention can be applied to the motor speed regulation field, the renewable energy power generation field and the like. With the method adopted, the problem of excessive current of connection loops between the units which is caused by a traditional carrier phase-shift SVPWM can be effectively solved; a large number of non-ideal switching states can be removed; voltage spikes and harmonics of an alternating-current side can be reduced; current-limiting inductors in hardware circuits can be omitted; a direct-current bus-bar voltage utilization effect that the SVPWM can achieve can be maintained; and generated redundant switching states canimprove the degree of freedom of control, and current harmonics can be effectively reduced.

Description

technical field [0001] The invention relates to a SVPWM modulation method of a converter. In particular, it relates to a SVPWM modulation method suitable for line voltage cascaded triple converters for motor speed regulation and renewable energy power generation. Background technique [0002] Power electronics technology continues to expand in the application fields of electric transmission and new energy power generation, and the voltage and power levels it faces are also constantly increasing. However, limited by the development speed of semiconductor technology, the voltage and power levels of a single semiconductor device are often difficult to adapt to some high-voltage and high-power applications. Among the voltage-type inverters, the traditional two-level inverter is dominant in the low-voltage and low-power field, but there are some inherent problems in the high-voltage and high-power field. For example, in order to improve the quality of the output waveform, it is ...

AI Technical Summary

Problems solved by technology

[0003] The modulation methods of the existing line voltage cascaded triple converters are mostly carrier phase-shifted sinusoidal pulse width modulation (CPS-SPWM) or carrier phase-shifted space vector modulation (CPS-SVPWM). The controller is regarded as an independent unit and controlled separately, without considering the mutual influence between the units, which will cause a large current between the units

Therefore, in the line voltage cascaded triple converter, a current-limiting inductor is usually added between the units to suppress the excessive current, which not only increases the complexity of the converter design, but also increases the efficiency of the converter. device cost

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