Research On The High-Power Soft-Switching PWM Converter Technique

Conventional PWM rectifier circuits, power electronic switching device turn-on under high voltage, turn-off under large current, and thus the existence of large losses, low frequency, big size, and electromagnetic interference and other serious shortcomings.In this paper, a zero-current soft-switching technology is used, and a zero-current soft-switching 100kVA of the PWM rectifier prototype projects is developed. The technology by increasing the auxiliary switch, the use of resonating by inductance and capacitance, in order to create zero-current switching conditions for switching devices, make the device in the process of switching, the switching losses is reduced, current and voltage to the rate of change is reduced, the electromagnetic interference is reduced effectively, and can work at higher inverter frequency, reducing the output filter inductor, capacitor size, thereby reducing the size of the entire device to improve performance.This article first introduced the high-frequency soft-switching technology development and the status quo, followed by an analysis of a ZCT soft-switching-based PWM rectifier of the main circuit topology and basic working principle. And then the 100kVA zero-current soft-switching PWM three-phase rectifier circuit engineering prototype of the main structure, parameter design and control system hardware and software design are elaborated. Control part used in TI's 32-bit high-performance digital signal processor TMS320F2812 as the core of the digital control system, control software using C programming language, to implement the idea of modular design, to enhance the generality and transportability of software.Finally, the experimental prototype 100kVA engineering data and waveform are analyzed. From the experimental results, the rectifier can achieve zero-current switching by a wide range of load, and switching loss significantly reduced, finally a comparative research of efficiency is given.