A low switching loss power inverter

Abstract

The invention discloses a low-switching-loss power inverter. The low-switching-loss power inverter comprises a direct-current power supply, a main switching tube, a lossless buffering circuit, a mainfreewheel diode, a three-phase full-bridge circuit and three-phase alternating current loads; the three-phase full-bridge circuits consist of six inverter switch tubes (a first inverter switch tube toa sixth inverter switch tube) and six freewheel diodes (a first freewheel diode to a sixth freewheel diode); the positive electrode of the direct-current power supply is connected with the drain electrode of the main switch tube, and the source electrode of the main switch tube is connected with the negative electrode of the main freewheel diode and the positive input end of the three-phase full-bridge circuit; the negative input end of the three-phase full-bridge circuit is connected with the positive electrode of the main freewheel diode and the negative electrode of the direct-current power supply; the lossless buffer circuit is connected with the main switch tube in parallel; and the u, v and w ends of the three-phase full-bridge circuits are connected with the three-phase alternatingcurrent loads respectively. The high-quality alternating-current voltage waveform can be output at a relatively low switching frequency, so that the switching loss is remarkably reduced, and meanwhile, the complexity of the three-phase full-bridge circuit is not increased.

Description

technical field [0001] The invention relates to the technical field of electric energy conversion, in particular to a low switching loss power inverter. Background technique [0002] A power inverter is a power conversion device that converts DC power into AC power. It is widely used in grid-connected systems, vehicle power supplies, household power supplies, electric tools, and motor drives. With the development of power electronic devices and power conversion technology, the working efficiency and output power quality of power inverters are gradually improving. Currently the most mature three-phase power inverter solution is a three-phase full-bridge circuit. The existing three-phase full-bridge circuit is composed of 6 inverter switching tubes and 6 freewheeling diodes, and can realize the output of symmetrical three-phase AC voltage through the three-phase sine wave modulation algorithm. The problems of the existing three-phase power inverter based on the three-phase f...

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Problems solved by technology

The problems of the existing three-phase power inverter based on the three-phase full-bridge circuit mainly lie in the following points: (1) The switching frequency of the inverter switching tube is limited. When the switching frequency is too high, the switching loss of the system is large and the heat generation is serious , when the switching frequency is too low, the quality of the output voltage waveform is poor and the current ripple is large; (2) The way to reduce switching loss is usually to add a loss reduction circuit to each inverter switching tube, resulting in a complex inverter topology. The difficulty of control increases, which affects the reliability of the circuit

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