Single-stage three-phase cascade voltage-type quasi-impedance source inverter with large step-up ratio

Abstract

A single-stage three-phase cascade voltage-type quasi-impedance source inverter circuit structure with a large step-up ratio is composed of an input DC power supply, a large step-up ratio impedance network, a three-phase inverter bridge, a three-phase filter, and a three-phase AC load or a three-phase AC network, which are sequentially connected in cascade. The large step-up ratio impedance network consists of an energy storage inductor, and n identical SLCC (subscriber line control circuit)-type two-port impedance network units sequentially connected in series, wherein n is a natural number larger than 1; and each SLCC-type two-port impedance network unit is composed of one power diode, one energy storage inductor and two energy storage capacitors. The three-phase inverter bridge consists of six two-quadrant power switches. The inverter provided by the invention can perform single-stage conversion on instable low-voltage DC current with wide change range to obtain stable high-quality three-phase sinusoidal AC current, has the advantages of single-stage power conversion, high power density, high conversion efficiency, large step-up ratio, high quality of the output waveform, high reliability, low cost and the like, and is suitable for medium-capacity and large-capacity three-phase inversion occasions.

Description

technical field [0001] The invention relates to a single-stage three-phase large step-up ratio cascaded voltage type quasi-impedance source inverter, which belongs to the power electronic technology. Background technique [0002] The inverter is a static converter device that uses power semiconductor devices to convert direct current into alternating current, which is used for AC loads or connected to the AC grid for power generation. [0003] Due to the increasing shortage of fossil energy (non-renewable energy) such as oil, coal and natural gas, serious environmental pollution, global warming, nuclear waste and environmental pollution caused by nuclear energy production, energy and the environment have become major issues facing mankind in the 21st century. . Renewable energy (green energy) such as solar energy, wind energy, hydrogen energy, tidal energy, and geothermal energy has the advantages of clean, pollution-free, cheap, reliable, and abundant. People pay more and ...

AI Technical Summary

Problems solved by technology

When this type of inverter works normally, the DC side voltage must be greater than the peak value of the AC side line voltage, so there is an obvious defect: when the DC side voltage (such as the output capacity of photovoltaic cells) decreases, such as rainy days or nights, the entire power generation system It will be difficult to run normally and the utilization rate of the system will drop

This is to effectively overcome the defects of the traditional PWM converter that the bridge arm must be set with dead time, the boost ratio is not large enough (non-isolated type), the volume and weight of the system are large and the cost is high (output plus three-phase power frequency transformer), etc., and improve It is of great significance to transform the output waveform quality and reliability of the system and reduce the EMI on the input side, to broaden the theory of power electronics inverter technology and renewable energy power generation technology, to promote the development of new energy power generation industry, and to develop an energy-saving and conservation-oriented society

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