Novel resonant DC-link soft switching inverter and modulation method thereof

Abstract

The invention provides a novel resonant DC-link soft switching inverter and a modulation method thereof, and relates to the technical field of inverters. The inverter comprises an auxiliary resonant circuit, an inverter bridge, a load circuit and a DC power supply, wherein the auxiliary resonant circuit comprises a bus switch tube, two auxiliary switch tubes, two auxiliary resonant inductors, a primary resonant capacitor, two auxiliary resonant capacitors, an anti-parallel diode of the bus switch tube and four auxiliary diodes; the inverter bridge is of a three-phase bridge structure; the load circuit is a three-phase resistor-inductance load; and various main power switch tubes of the inverter bridge work in manners of sine pulse width modulation and complementary turn-on at a phase difference of 180 degrees. According to the novel resonant DC-link soft switching inverter, a zero-crossing reverse process of current of each auxiliary resonant inductor is avoided, the service life of the inverter is prolonged, and the current stress of the auxiliary switch tubes of the inverter, the conduction loss of the auxiliary resonant circuit and the switching losses of the bus switch tube and the auxiliary switch tubes are effectively reduced.

Description

technical field [0001] The invention relates to the technical field of inverters, in particular to a novel resonant DC link soft-switching inverter and a modulation method thereof. Background technique [0002] After Professor D.M.Divan proposed soft-switching inverter technology in 1986, due to its great potential application value in various aspects, especially in power supplies, it has attracted extensive attention from experts and scholars from various countries and has become a research hotspot. Compared with traditional hard-switching inverters, soft-switching inverters achieve high frequency by reducing switching losses and improving device efficiency. As the switching frequency increases, the volume and weight of the soft-switching inverter decrease, the power density increases, and the PWM control effect improves; the soft-switching inverter can also reduce the inrush current, improve the operating environment of the power switching device, and improve Reliability ...

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Problems solved by technology

However, the inverter still has shortcomings: ①The auxiliary resonant circuit uses an inductor, and there is a zero-crossing reverse process of the inductor current. Due to hysteresis, the inductor coil will produce hysteresis loss and magnetic saturation, shortening the inverter The service life of the transformer; ②The current flowing through the auxiliary resonant circuit is the sum of the resonant current and the load current at the time of commutation, so in the full load range, even in the case of no load, the auxiliary resonant circuit must flow through a large current, resulting in larger current stress of the auxiliary switching tube and conduction loss of the auxiliary resonant circuit

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