An improved double-auxiliary resonant pole type three-phase soft-switching inverter circuit

Abstract

The invention provides an improved dual-auxiliary resonant pole type three-phase soft-switching inverter circuit, which relates to the technical field of power electronics. The circuit includes a three-phase main inverter circuit and a three-phase double auxiliary resonant converter circuit. The main inverter circuit of each phase includes two main switching tubes and two main diodes; the double auxiliary resonant converter circuit of each phase includes four auxiliary switching tubes, two main resonant capacitors, four auxiliary resonant capacitors, two auxiliary resonant inductor and six auxiliary diodes. The improved dual-auxiliary resonant pole type three-phase soft-switching inverter circuit provided by the present invention, while completing the simplification of the double-auxiliary resonant commutation circuit and the decoupling of the resonance process, adds two auxiliary resonant capacitors that limit the rate of voltage change, so that The current stress of the double auxiliary resonant converter circuit is approximately equal to the peak load current, so that the conduction loss of the double auxiliary resonant converter circuit is effectively reduced, and the efficient power conversion of the inverter in the full load range is maintained.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an improved double-auxiliary resonant pole type three-phase soft-switching inverter circuit. Background technique [0002] Today, with more and more frequent power conversions, the application places of inverters are expanding day by day, and inverters can be seen in fields such as new energy power generation, motor drives, and uninterruptible power supplies. With the development of inverters, people's requirements for inverters are getting higher and higher, and inverters with high frequency, miniaturization, and light weight are more and more desired by people, and the introduction of soft switching technology is just in time. Soft switching technology can not only solve the switching loss problem caused by the increase of switching frequency, but also reduce electromagnetic noise (EMC) and electromagnetic interference (EMI), so as to create a safe, green and efficien...

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Problems solved by technology

However, the inverter still has deficiencies: ① The auxiliary resonant commutation circuit of the inverter uses many devices and is too complicated. More devices not only mean the complexity of the circuit and the increase of the production cost, but also mean that the actual The number of possible fault points in the system increases, thereby increasing the potential safety hazard of the system; ②The auxiliary resonant commutation circuit of the inverter has two groups of resonant components coupled with each other, and the resonant commutation process is coupled with each other, and system oscillation is difficult to avoid; ③ The second set of auxiliary resonant capacitors of the inverter cannot be fully pre-charged under certain load conditions, resulting in an uncontrollable output voltage change rate at this time, which will bring extremely adverse effects in AC drive applications

[0006] However, the inverter still has shortcomings: there is a contradiction between the voltage change rate when the main switching tube is turned off and the current stress of the auxiliary resonant commutation circuit, so that the main resonant capacitor and auxiliary resonant capacitor cannot be used in the parameter design of the inverter. The limit is small, so the current stress cannot reach the level approximately equal to the peak value of the load current, which makes the current stress and conduction loss of the double auxiliary resonant commutation circuit higher, reducing the conversion efficiency of the inverter

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