Novel unidirectional three-phase three-level rectifier based on soft switching technology

Abstract

A novel unidirectional three-phase three-level rectifier based on a soft switching technology comprises a unidirectional three-level rectifying loop, a resonant circuit, a buffer loop, a voltage sampling circuit, a current sampling circuit, a zero-crossing comparison circuit, a DSP control module and a PWM drive circuit, wherein the unidirectional three-phase three-level rectifying loop is composed of three rectifying bridge arms including six power switch tubes, so that the number of elements is effectively reduced, the structure is simplified, and the cost is reduced. The resonant loop is composed of a resonant inductor, a clamping capacitor, an auxiliary switch and the like, zero-voltage switching-on of main switches can be achieved, and switching loss and switching noise are effectively reduced. And the buffer loop is composed of six capacitors connected in parallel with the main switches, so that the turn-off process of the main switches can be softer. By the adoption of the structure, a double closed-loop control mode is adopted, a control method combining PI control and SVPWM is adopted for a current inner loop and a voltage outer loop, and therefore harmonic waves are effectively restrained, and alternating-current-side current sine, voltage stable output and grid-side unit power factor control are achieved.

Description

technical field [0001] The invention relates to the technical field of three-phase rectifiers, in particular to a novel unidirectional three-phase three-level rectifier based on soft switching technology. Background technique [0002] With the rapid development of power electronic technology, power electronic equipment is increasing in daily life and work production, such as various high-quality application power supplies, electric traction locomotives and other electrified railway equipment, frequency conversion speed control systems, various new energy power generation, etc. . As an important technology to improve system performance and improve system efficiency, multi-level conversion technology has received more and more research from academia and industry in high-power fields such as new energy inverters connected to the grid, distributed DC power generation, and transmission systems. favor. Due to the increasingly strong demand for high-voltage resistance, high-frequ...

AI Technical Summary

Problems solved by technology

Due to the increasingly strong demand for high-voltage resistance, high-frequency, high-voltage, and large-capacity characteristics of power electronic devices, there are many bottlenecks that are difficult to break through in the application of traditional two-level converters in high-power applications.

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