| Solar energy is an inexhaustible, clean energy.The photovoltaic cell is the most direct and most important form of photovoltaic utilization. However, the conversion efficiency of the photovoltaic cell is affected by various factors such as material(the conversion efficiency of monocrystalline silicon,polycrystalline silicon and thin film transistor are different) and external conditions like light intensity and battery temperature.All of these factors greatly influence the efficiency of photovoltaic power generation system.Based on hybrid solar photovoltaic–thermal(PV/T) system with compound parabolic concentrator(CPC),the optical model of the photovoltaic cell is established.The simulation results present that in the point about 80% of the open-circuit voltage,the solar panels will reach its maximum power.And when the outside conditions change the maximum power will change,the stronger the intensity of illumination,the lower the panels temperature, the greater the maximum power.According to optical model of the photovoltaic cell determine the maximum power point tracking strategy,so as to improve the photoelectric efficiency.Due to the CPC focusing condenser, high intensity illumination which make the temperature of the panels increase is geted.The high temperature of the panels reduce the photoelectric efficiency.So PV/T collectors are exploited..When the cold water flow through the channel which is in the lower part of the collector,the cold water will take some heat of the panels by heat exchanging.And the temperature of cell panels will reduce.The temperature of the cell panels is influenced by the light intensity,the initial temperature and the mass flow rate of the cooling water.Establish the model of the PV/T collector,the cell panels temperature transfer functions are geted. To get the more accurate transfer function, PSO intelligent optimization algorithm is introduced. According to the transfer function of cell panels temperature,to determine the parameters of PID controller of the control systerm which is used to ensure the cell panels temperature in a suitable range. So that the panels achieve maximum efficiency,also get hot water for further use. |
