A Novel Unidirectional Three-Phase Three-Level Rectifier Based on Soft Switching Technology

Abstract

A new type of unidirectional three-phase three-level rectifier based on soft switching technology, including a unidirectional three-level rectifier circuit, a resonant circuit, a buffer circuit, a voltage sampling circuit, a current sampling circuit, a zero-crossing comparison circuit, a DSP control module, and a PWM drive circuit . Among them, the unidirectional three-phase three-level rectification circuit consists of six power switch tubes to form three rectification bridge arms, which effectively reduces the number of components, simplifies the structure and reduces the cost. The resonant circuit is composed of resonant inductor, clamping capacitor, auxiliary switch, etc., which can enable the main switch to realize zero-voltage turn-on, effectively reducing switching loss and switching noise. The snubber circuit is composed of 6 capacitors connected in parallel with the main switch, which can make the turn-off process of the main switch softer. With the above structure and double closed-loop control mode, both the current inner loop and the voltage outer loop adopt a control method combining PI control and SVPWM, so as to effectively suppress harmonics, realize sinusoidalization of current on the AC side, stable output of voltage and grid-side Unity power factor control.

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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