Double-staggered flyback photovoltaic grid-connected micro inverter and control method thereof

Abstract

The invention discloses a double-staggered flyback photovoltaic grid-connected micro inverter and a control method thereof. The double-staggered flyback photovoltaic grid-connected micro inverter comprises a direct-current-side capacitor, a double-flyback converter, a converter bridge and an output filter, wherein two high-frequency transformers of the double-staggered flyback converter respectively have a double-secondary winding structure, so a system can work in a staggered flyback mode at any time, and requirements of the system on the saturation current of the high-frequency transformers, magnetic cores, input output capacitance and the rated current of a power metal oxide semiconductor field effect transistor (MOSFET) are reduced; the converter bridge consists of two thyristors; and by using an active conversion method, the quality of grid-connected current waveform is ensured on the premise that the reliability of the system is ensured. The double-staggered flyback photovoltaic grid-connected micro inverter can efficiently convert and transmit energy without pollution, and has the characteristics of compact structure, low cost, reliability and practicability.

Description

technical field [0001] The invention belongs to the field of new energy photovoltaic grid-connected power generation, in particular to a double-interleaved flyback photovoltaic grid-connected micro-inverter and a control method thereof. Background technique [0002] Energy is the core element and key driving force of the development of human society. With the development of human society, the current energy structure has increasingly highlighted its shortcomings, such as the depletion of conventional energy and unfriendly environment. Solar energy has received more and more attention due to its richness and cleanliness. The large-scale development of solar energy is conducive to responding to the growing energy demand, alleviating the energy crisis, and reducing environmental pollution. In order to achieve sustainable energy development, many developed countries actively promote roof plan and external wall photovoltaic grid-connected power generation technology. Their succe...

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Problems solved by technology

However, there are still the following shortcomings: (1) The structure of the two-stage interleaved anti-laser photovoltaic grid-connected inverter is not compact enough, and the power density of the system is low; (2) The input capacitance of the DC side is still too large, and the voltage and current of power devices The stress is large, especially when working in the current discontinuous mode, which makes the efficiency of the whole machine not high enough, and the warranty life cannot be close to the same as that of photovoltaic modules; (3) In order to ensure reliable commutation of the system, the full-bridge converter will A relatively large dead zone is inserted, and the large distortion of the grid-connected current at the zero-crossing point reduces the quality of the grid-connected current waveform

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