Single-level single-phase large-step-up-ratio cascade connection voltage type convertor of quasi impedance source

Abstract

The invention provides a circuit structure of a single-level single-phase large-step-up-ratio cascade connection voltage type convertor of a quasi impedance source. The circuit structure of the single-level single-phase large-step-up-ratio cascade connection voltage type convertor of the quasi impedance source is composed of an input direct-current power source or a single-phase alternating current power source, a high frequency combination modulation switch, a filter, a single-phase alternating current load or a direct-current load, wherein the input direct-current power source or the single-phase alternating current power source, the high frequency combination modulation switch, the filter, the single-phase alternating current load or the direct-current load are connected in a cascading mode in sequence. A large-step-up-ratio impedance network is connected between the input power source and the high frequency combination modulation switch. The large-step-up-ratio impedance network is formed by series connection of an energy storage inductor and n SLCC type two-port impedance network units, wherein the n SLCC type two-port impedance network units are the same and are connected in a cascading mode in sequence. The n is a natural number larger than one. Each SLCC type two-port impedance network unit is composed of a power diode or a four-quadrant power switch, an energy storage inductor and two energy storage capacitors. The high frequency combination modulation switch is composed of a two-quadrant power switch or a four-quadrant power switch. The convertor can effectively convert an unstable low-voltage direct current with a wide changing ranged or a single-phase alternating current into a stable and high-quality single-phase sinusoidal alternating current or direct current in a single-level mode and can be applied to occasions of electrical energy conversion with medium and small capacity.

Description

technical field [0001] The invention relates to a single-stage, single-phase, large-boost ratio series voltage quasi-impedance source converter, which belongs to the power electronics technology. Background technique [0002] A converter is a static converter device that uses power semiconductor devices to convert direct current or alternating current into alternating current or direct current, for use with alternating current loads (including grid-connected power generation with an alternating current grid) or direct current loads. [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 energy production will produce nuclear waste and pollute the environment, 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 e...

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 phase 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 The system will be difficult to run normally, and the utilization rate of the system will drop

This is to effectively overcome the shortcomings of traditional PWM converters such as the dead time of the bridge arm, the boost ratio is not large enough (non-isolated), the volume and weight of the system, and the high cost (input or output plus single-phase power frequency transformer) and other defects. , improve the output waveform quality and reliability of the conversion system and reduce the EMI on the input side, broaden the theory of power electronics conversion technology and renewable energy power generation technology, promote the development of new energy power generation industry and develop an energy-saving and conservation-oriented society. significance

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