Single phase grid-connected inverter reactive output control method

Abstract

The invention relates to a grid-connected inverter control method and in particular to a single phase grid-connected inverter reactive output control method. The single phase grid-connected inverter reactive output control method is characterized by providing a control unit, the control unit is used for changing control method of the single phase grid-connected inverter according to the fact that whether a power grid has reactive output, when the power grid has no reactive output requirements, the control unit controls the single phase grid-connected inverter to be at a unipolar working mode, and when the power grid has reactive output requirements, the control unit controls the single phase grid-connected inverter to be at a bipolar working mode. The single phase grid-connected inverter reactive output control method overcomes the shortcoming of the single control mode of the single phase grid-connected inverter in outputting reactive energy, achieves accuracy and controllability in outputting target phase position, and achieves adjusting and control of power factors. Under the condition of poor power grid quality, the single phase grid-connected inverter performs certain compensation on power grid waveform through outputting reactive power and has the advantages of being low in loss and high in complete machine efficiency.

Description

technical field [0001] The invention relates to a control method of a grid-connected inverter, in particular to a reactive power output control method of a single-phase grid-connected inverter. Background technique [0002] The reactive power of the load is generally provided by the power grid or by special reactive power compensation equipment. For the complex power supply network in the city, when its power supply and transmission capacity is strong, the reactive power of the load will not have a great impact on the power supply quality of the grid. However, the reactive current of the load at the end of the power grid, especially in the edge areas far away from the power grid, will have a greater impact on the power supply voltage of the power grid, and then affect other users who share the transmission line of the power grid. [0003] At present, there are new energy grid-connected inverter products such as solar energy and wind energy on the market, and their working me...

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Problems solved by technology

[0004] For single-phase grid-connected inverters with power less than 4.6KVA, the simple unipolar control method is adopted, and the grid-connected current waveform is distorted during reactive power compensation, and reactive power control of the grid-connected current cannot be realized; bipolar control mode, large loss, and large current ripple, single-phase grid-connected inverter index deterioration

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