Optimizing The Output Power Of Photovoltaic-Thermoelectric Coupling System Under The Partial Shadow

Research on new energy generation technologies is widely used in the field of renewable energy,and how to increase the output power of photovoltaic systems has been the focus of research,In addition to a small part of the energy in photovoltaic cells being converted into electricity,most of the energy is dissipated in the form of heat,causing great waste,and because the heat of the photovoltaic cells themselves is not easily dissipated in time,reducing the output power of the cells.In order to reduce the loss of heat from the surface of the photovoltaic cells,a coupled photovoltaic-thermoelectric system is formed on the basis of the photovoltaic cells in combination with a temperature differential sheet using waste heat.However,in the PV-thermoelectric coupling system,the partial shadows shade part of the PV cell surface,making its surface temperature uneven,which in turn makes the temperature difference device in the process of heat absorption due to the unevenness of the temperature difference output characteristics,reducing the output power of the PV-thermoelectric coupling system.In order to reduce the impact caused by local shadows,this paper presents the structural design and control strategy optimization of the coupled photovoltaicthermal system.Firstly,the structural design and heat dissipation methods of the coupled photovoltaicthermoelectric system are investigated.The micro heat pipe is used as a heat conductor between the PV panel and the temperature differential sheet to analyze the heat dissipation of the PV array and study the heat dissipation and temperature equalization of the PV back sheet under different conditions,and control the temperature of the whole PV cell to maintain an overall uniformity by regulating the flow rate of the heat flow at the hot end of the temperature differential cell and the flow rate of the cooling water at the cold end to ensure a smooth output of the temperature differential power generation device.Secondly,the hardware circuit design and control strategies of the photovoltaic and thermoelectric systems are investigated.Through the hardware design of the PV and thermoelectric system,the design index of the system was selected,the parameters of the DC-DC converter circuit of the PV and thermoelectric system were designed,as well as the design of its driver circuit,sampling circuit,and auxiliary power supply circuit,and the STM32 was used as the main control system to complete the A/D conversion,PWM wave output,and temperature measurement.Boost circuits are used as energy conversion circuits for the PV and temperature difference systems respectively to give a stable output.The chaotic optimization algorithm is introduced into the quantum particle swarm algorithm,using the law of iterative decrement to improve the size of the weight coefficients through the sinusoidal function to complete the tracking of the maximum power point of the PV system,while the variable step size of the conductance increment method is selected to track the output power of the thermoelectric system to improve the tracking accuracy and output of the whole device.Finally,a simulation and experimental test platform for coupled photovoltaic-thermoelectric systems under partial shading are built.The SIMULINK simulation models for the PV system and the temperature difference system were built using MATLAB software to simulate the output of the PV and temperature difference under partial shading and to analyze the output effect of the PV and temperature difference systems based on the simulation results.The temperature profile of the shaded and non-shaded areas,the PV output power,the thermoelectric output power,and the thermal uniformity of the temperature difference power generation sheet were tested on the shaded and nonshaded areas of the PV cell surface of the improved and unimproved photothermal co-generation system installations when the shading cover shaded 10%,30% and 50% of the PV cell area respectively.The results show that: When the area of the shaded PV panel is 10% of the total area of the PV panel,the heat flow rate at the host port is 0.0124 m/s,and the water flow rate at the cold end is0.0135 m/s,the average temperature difference between the shaded and non-shaded areas of the PV cell is about 274.15 K.The average power output of the PV is increased by 18.79% and the average power of thermoelectric output is increased by 1.92 %.This provides a reference for further research on photothermal combined power generation systems.