Research On A Three-port Converter For Photovoltaic And Storage Generation

With the fast development of the world economy, the environmental problem is increasingly serious, which strong stimulates the development of solar energy, wind energy, geothermal for new energy power generation technology. Traditional optical storage power generation system has some disadvantages, such as the large number of converters, large volume and low power density. The use of three-port converter instead of the original multiple single input single output DC-DC converter has the advantages of simple system structure, small volume, low cost and high power density. Those wake three-port converter become a hotspot in the research of the power electronic technology. This paper aims at a novel three-port converter for photovoltaic and storage generation.The topology of the three-port converter for photovoltaic and storage generation is introduced. Then four working modes of the three-port converter are determined and the principle of each working mode is analyzed. According to the change of the external conditions, such as light and temperature, the dynamic switching process of various model of the three-port converter is discussed.The control strategy of the three-port converter, including the output voltage controller, storage battery voltage controller, the battery current controller and the input voltage controller based on port control variables, which finally obey an interval controller scheduling, is analyzed and designed. The control signal of the interval controller comes from the load voltage error after compensation. The control signal is classified into battery discharging range, battery charging range and distribution range by function. In order to make the three port converter have good output characters, a double loop control method is adopted. The small signal modeling of three-port converter is analyzed in this paper.After that, the main circuit parameters of the three-port converter are designed. The voltage regulating circuit, current of the converter control circuit and drive circuit of the three-port converter is determined. Based on control strategy, software system of three-port converter is designed. According to the above theoretical analysis, the model of PV array and three-port converter is set up in Matlab/Simulink. The simulation results of the closed loop for each working interval verify the rationality of the design of the system. Finally, three-ports for photovoltaic and storage generation system prototype is built up on the basis of the above analysis. This prototype uses the TMS320F2812 chip of TI company as the core for optical storage power generation. The correctness of the above analysis is verified by experiment s.