High-efficiency stable photovoltaic single-phase grid connected control method with double MPPT functions

Abstract

The invention provides a high-efficiency stable photovoltaic single-phase grid connected control method with double MPPT functions and belongs to the technical field of photovoltaic generating control. The method is characterized in that: a high-speed digital signal processor and a C-language dynamic fixed point algorithm are utilized for forming a high-performance high-reliability control algorithm for an overall photovoltaic single-phase grid connected control system; by using a two-stage type grid connected control structure, a maximum power point tacking strategy of double MPPT rapid smoothing, and a grid connected current prediction dead-beat control algorithm, multiple strings of photovoltaic arrays are enabled to be at optimization operation states and the maximum energy emitted by the photovoltaic arrays is transformed through a stable bipolar type structure for outputting to a local electrical network; and at the time when the multiple strings of photovoltaic arrays are provided with double MPPT maximum power point tacking and grid connected current prediction dead-beat control, photovoltaic grid connected current is enabled to be completely consistent with a local single-phase voltage phase. The advantages are as follows: the power factor is 1, and the grid connected current harmonic wave distortion rate is lower than 3%, thus the system operation is safe and reliable.

Description

technical field [0001] The invention relates to an efficient and stable dual-MPPT function photovoltaic single-phase grid-connected control method, which belongs to the application field of photovoltaic power generation system control technology. Background technique [0002] The development and utilization of abundant and vast solar energy without and less pollution to the environment is not only an urgently needed supplementary energy in the near future, but also the basis of the future energy structure. At present, the use of this clean energy is rapidly entering the commercial growth stage. Under such a premise, the development and application of solar photovoltaic power generation technology has become the focus of worldwide attention. The advantages of solar power generation are: no risk of depletion, absolutely clean, not limited by the geographical distribution of resources, can generate electricity nearby where the power is used, high energy quality, relatively sho...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a high-efficiency, stable, bipolar photovoltaic single-phase grid-connected control method with dual MPPT functions; the self-developed single-phase photovoltaic grid-connected control system does not need to consider the nature of the load, and can play a role in the power grid. The use of solar power to generate electricity can save a lot of coal and oil, so that the power factor of the current connected to the local power grid can be completely 1; the multi-string photovoltaic array can always run at the maximum power point, from large to large The power grid accepts all the electric energy generated by solar energy, overcomes the problem of mismatching performance and power of multi-string photovoltaic arrays, avoids the influence of shadow phenomenon on system efficiency, and improves the efficiency of solar power generation; omits the battery as an energy storage link, eliminating the need for The operation and maintenance costs brought by the battery, and also eliminate the indirect pollution caused by the disposal of waste batteries

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