Control method for maximum power point capture system of photovoltaic power generation system

Abstract

The invention discloses a photovoltaic power generation system maximum power point capturing system and a control method thereof. The system is composed of a photovoltaic power generation main loop and a photovoltaic power generation control loop; the photovoltaic power generation main loop is composed of a photovoltaic array, a direct current converter and a load, and the photovoltaic power generation control loop is composed of a vector measuring unit and an MPPC unit. According to the method, fast capturing of a photovoltaic power generation system maximum power point is achieved online, that is to say, a technology of positioning and capturing in one step is achieved online; through arrangement of a maximum power point stable range, the problem of static response oscillation is eliminated; photovoltaic array output voltage basically identically equals to maximum power point voltage, and output power is basically identically equal to the maximum power. By means of the method, photovoltaic array output fluctuation caused by solar power fluctuation and load fluctuation is reduced to an extreme; particularly, the problem of loss of control possibly caused by solar power drastic fluctuation is eliminated.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaic power generation applications, in particular to a photovoltaic power generation system maximum power point capture system and a control method thereof, which are suitable for photovoltaic power generation systems to maintain maximum power point output or photovoltaic power generation systems to generate electricity with the highest photoelectric conversion efficiency. Background technique [0002] With the continuous improvement of the whole society's requirements for sustainable development and environmental protection, vigorous research and development and application of renewable energy have become the consensus of the whole world. Solar photovoltaic power generation is one of the renewable energy application technologies. Due to the universality of solar energy, countless scientific and technological workers are attracted to develop its application technology. However, due to the l...

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Problems solved by technology

In addition, due to the incomplete or inaccurate photovoltaic P-V curves based on many MPPT technologies based on the extreme value principle, the MPPT controller will generate wrong disturbances when the solar light intensity changes drastically, such as Figure 5 As shown, this is the second main problem of photovoltaic power generation technology

[0004] Aiming at the question of how large the disturbance step size is in MPPT technology, there is no unified conclusion whether to use a fixed step size or a variable step size, which is an inherent defect of MPPT technology

[0005] Aiming at problem 2, the MPPT technology based on the extreme value principle may produce wrong disturbances when the sunshine intensity changes drastically, indicating that there is a problem with the basis of its control technology

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