Maximal power output optimization and control method for partially sheltered photovoltaic system

Abstract

The invention provides a maximal power output optimization and control method for a partially sheltered photovoltaic system, which belongs to the technical field of photovoltaic power generation. The method comprises the following operation processes of: setting an original pulse width modulation signal (PWMs) in a photovoltaic circuit; collecting a voltage signal (VS) and a current signal (CS) of an output end; performing analogue / digital (A / D) conversion on the VS and CS and inputting the conversion result into a singlechip A; calculating an output power value at a current time; calling a disturbance PWM method; judging whether a system output is stable or not, and if the system output is not stable, returning to the second step to perform the operation, and if the system output is stable, calculating and storing the PWM value and the output power; disturbing and scanning + / -25 percent of area around the PWM by using + / -1 percent of step length; judging whether a new maximal power point exists, and if no new maximal power point exists, storing and outputting an optimized PWM wave and the maximal power and if the new maximal power point exists, storing and output the maximal power and the PWM wave of the new maximal power point; and judging whether the maximal power of the system output has over 5 percent of change, and if so, returning to the second step to perform the operation again and otherwise, ending the process.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and in particular relates to an optimal control method for maximum power output of a photovoltaic power generation system under partial shading conditions. technical background [0002] At present, the development and utilization of renewable energy has been increasingly concerned by the governments of various countries, and the conversion of solar energy into electrical energy through photovoltaics has great development potential in the near future. According to the forecast of the EU Joint Research Center in 2004, by the end of this century, the proportion of photovoltaic power generation in the world's energy supply will exceed 60%. At present, the problems of photovoltaic power generation system (hereinafter referred to as "system") are high investment cost, low output efficiency, and unstable output power. Partial shading often occurs, and the shaded part not only cann...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a control method suitable for easily realizing the maximum output power of a photovoltaic power generation system under partial shading conditions, which can effectively overcome the poor precision, poor adaptability, low tracking efficiency and large amount of calculation in the prior art. shortcoming

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