Photovoltaic high-frequency chain grid-connected inverter capable of restraining input low-frequency current ripples

Abstract

The invention discloses a photovoltaic high-frequency chain grid-connected inverter capable of restraining input low-frequency current ripples. The inverter comprises a first inverter, an LCL-T resonance network, a high-frequency transformer, a rectifier circuit, a direct-current filter circuit, a second inverter and an LCL filter. The input end of the first inverter is connected with a photovoltaic array, and the output end of the first inverter is connected with the LCL-T resonance network. The LCL-T resonance network comprises a T circuit which is composed of an inductor Lr, a capacitor Cr and an inductor Lk. The inductor Lr is connected to the output end of the first inverter in series, and the inductor Lk is connected with the primary side of the high-frequency transformer in series and then connected with the capacitor Cr in parallel. The secondary side of the high-frequency transformer is connected with the rectifier circuit, the direct-current filter circuit and the second inverter in sequence. The LCL filter is connected to the output end of the second inverter, and the output end the LCL filter is electrically connected with a grid. By applying the LCL-T resonance network to the photovoltaic high-frequency chain grid-connected inverter, the low-frequency current ripples in output current of a photovoltaic module can be effectively restrained.

Description

technical field [0001] The invention relates to a photovoltaic high-frequency chain grid-connected inverter with the function of suppressing input low-frequency current ripple. Background technique [0002] With the continuous decline in the price of photovoltaic modules and the promulgation of relevant national policies and regulations, photovoltaic power generation will surely become an important part of the utilization of renewable energy. In the photovoltaic system, the power converter plays a very important role, including the maximum power point tracking (MPPT) of the photovoltaic cell, and the form of electric energy required by the high-quality output load. The decline in the price of photovoltaic cells has led to an increasing proportion of the cost of power converters in photovoltaic power generation systems; in addition, the efficiency of converters directly determines the utilization of photovoltaic modules. Therefore, low cost and high efficiency are the goals ...

AI Technical Summary

Problems solved by technology

Usually, the two-stage circuit suppresses LFCR on the input side by using a high-performance controller, but this kind of method generally has problems such as controller design and digital implementation difficulties.

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