Single-phase to three-phase power supply conversion system based on power electronic transformer

Abstract

The invention relates to a single-phase to three-phase power supply conversion system based on a power electronic transformer and a control method. The single-phase to three-phase power supply conversion system comprises a single-phase rectification input stage, a high-frequency transformation isolation stage, a three-phase inversion output stage and a low-pass filter, an uncontrolled rectification strategy is adopted for a transformer secondary side diode rectification circuit in the single-phase rectification input stage and the high-frequency transformation isolation stage; an EPWM controlstrategy is adopted to output high-frequency square waves for a transformer primary side single-phase inversion H-bridge circuit in the high-frequency voltage transformation isolation stage; and an SVPWM control strategy is adopted for the three-phase inverter output stage, and frequency conversion and voltage transformation control over the three-phase inverter output voltage is achieved. By adopting the conversion system and the control method system, the problems of distortion and harmonic pollution of three-phase alternating-current voltage waveforms after inversion can be avoided; and thedirect-current bus can obtain different levels of voltages through voltage transformation of the high-frequency transformer, so that voltage transformation and frequency conversion output after three-phase inversion is realized, and the three-phase inverter is used for an electricity utilization occasion of converting single-phase into three-phase power.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a single-three-phase power conversion system and control method based on power electronic transformers. Background technique [0002] In electrified railway systems, industrial power systems and civil power systems, the technology of converting single-phase power to three-phase power has not been well resolved for a long time. [0003] Most of the circuits in the existing technical schemes adopt the typical AC-DC-AC topology structure. Although the circuit topology structure is relatively simple, the circuit control is simple, and the dynamic response is good, it lacks the rectification stage and inverter in the single-three-phase inverter power supply. Level isolation may cause distortion and harmonic pollution of the three-phase AC voltage waveform after inverter. At the same time, the circuit topology of the previous technical solutions does not realize the voltage transformation...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a single-three-phase power conversion system and control method based on power electronic transformers, so as to solve the lack of isolation between the rectification stage and the inverter stage in the single-three-phase inverter power supply in the prior art solution circuit, It may cause problems such as distortion and harmonic pollution of the three-phase AC voltage waveform after inverter

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