Study Of Mppt Control Strategy For Photo Voltaic Power Generation System

Thousands of years before the development of human, the consumption of energy supply exceeds demand. With the rapid development of global economy, science and technology advances by leaps and bounds, the human to coal, oil, natural gas and other fossil energy demand is rising, the energy shortage, energy crisis is imminent.Solar energy with its with its clean, efficient, never failure and use of the advantages of high value, and favored by governments around the world and experts, to occupy the dominant position in the energy market in the future. Solar photovoltaic power generation is the main way of using, compared with previous other energy generation, solar photovoltaic power generation has many advantages is unable to have other energy sources. The constant improvement of photovoltaic technology, the cost decrease, the development of photovoltaic technology industry brings out the sweeping.In order to improve the efficiency of photovoltaic power generation systems, on the one hand, can improve the conversion efficiency of the battery, on the other hand can also improve the working efficiency of the photovoltaic system. Based on the working principle of the photovoltaic cells as a starting point, set up the equivalent mathematical model of photovoltaic cells, respectively analyzed under the condition of single peak and peak output characteristic of the photovoltaic system, and put forward the response to both maximum power tracking control algorithm, and has reached the aim of maximum power tracking.A single peak, On photovoltaic cell modeling, analysis of the P- U characteristic curve, based on the incremental conductance method, summed up a optimized MPPT control algorithm, adaptive step length conductance increment method. This algorithm is introduced into step length control factor to make the system to track the maximum power point, more to improve the output power. Simulation shows that this kind of method to improve the tracking speed and reduced near the maximum power point oscillation phenomena have obvious effect.Peak condition, Peak situation occurs more in order to avoid the local hot spot effect caused by shadows of security issues, the bypass diode in parallel on the photovoltaic cells. Because of the traditional MPPT control algorithm is only applicable to single peak, is applied to the peak, more often trapped in a local maximum, unable to seek global maximum. Mathematical model analysis of partial shadow photovoltaic cells, study the photovoltaic battery output characteristic curve, peak scanning discriminant method is proposed. By controlling the voltage, in turn, to seek the extreme value point, judging the extreme value point power size, through the analysis and comparison of maximum power point of leaving. Finally through the simulation, this algorithm under the condition of partial shadow have sought the role of the maximum power point, can significantly improve the system output power.