A Novel Resonant DC Link Soft Switching Inverter and Its Modulation Method

Abstract

The invention provides a novel resonant DC link soft-switching inverter and a modulation method thereof, which relate to the technical field of inverters. The inverter includes an auxiliary resonant circuit, an inverter bridge, a load circuit and a DC power supply. The auxiliary resonant circuit includes a bus switching tube, two auxiliary switching tubes, two auxiliary resonant inductors, a main resonant capacitor, two auxiliary resonant capacitors, a bus The anti-parallel diodes of the switching tubes and four auxiliary diodes, the inverter bridge is a three-phase bridge structure, the load circuit is a three-phase resistive load, the main power switching tubes of the inverter bridge are modulated according to the sinusoidal pulse width, and the phase difference is 180° Complementary opening mode works. The invention avoids the zero-crossing reverse process of the auxiliary resonant inductor current, prolongs the service life of the inverter, effectively reduces the current stress of the auxiliary switch tube of the inverter, the conduction loss of the auxiliary resonant circuit, and the bus switch tube and the auxiliary switch tube switching loss.

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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