Double-bus normal-shock type micro-inverter front-end circuit and control method thereof

Abstract

The invention discloses a double-bus normal-shock type micro-inverter front-end circuit and a control method thereof. A dotted terminal of an auxiliary side coil of a transformer is connected with an anode of a first diode. A cathode of the first diode is connected with one end of an energy storage inductor, a drain of a second switch tube and a cathode of a fourth diode. The other end of the energy storage inductor is connected with a drain of a third switch tube and an anode of a second diode. A cathode of the second diode is connected with a drain of a fifth switch tube. A source of the fifth switch tube is connected with a positive pole of a thin-film capacitor and a drain of a fourth switch tube. A source of the fourth switch tube is connected with a source of the second switch tube, an anode of the fourth diode, a cathode of a third diode and one end of a filter inductor. Direct currents are converted into rectification half-sinusoids, the rectification half-sinusoids are converted into alternating currents after being unwound through a later-stage circuit, and decoupling capacitor capacitance can be reduced greatly; the thin-film capacitor can be adopted in a micro-inverter, and therefore the service life of a photovoltaic system is prolonged, and the stability of the system is improved.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic grid-connected power generation, and in particular relates to a front-end circuit of a double-bus forward micro-inverter and a control method thereof. Background technique [0002] Photovoltaic grid-connected power generation is one of the means to solve the world energy crisis. In existing installations, photovoltaic devices are widely used in the form of series, parallel or series-parallel. Not only is the system not easy to expand, but also problems such as differences in component characteristics and partial shadows will cause a significant drop in the output power of the photovoltaic array. The micro-inverter can effectively solve the above problems, but it is limited to the structure and working principle. It needs a large-capacity electrolytic capacitor for power decoupling, but its short working life and poor characteristics at high temperature lead to the reliability of the micro-inv...

AI Technical Summary

Problems solved by technology

High-gain DC-DC converters can meet the grid-connected operation of inverters when the input voltage varies greatly, but the complex structure and control algorithm make them unsuitable for price-sensitive micro-inverters

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