Research On The Interleaved Parallel Flyback Micro Converter

With the exploitation of fossil energy,the traditional fossil fuels such as coal become more precious,so the environmentally friendly and continuable solar energy has been widely concerned.With the development of science and technology,solar power generation has begun to change from large-scale integration to miniaturization and protability.N this process,for the low power applications,micro inverter has received more attention.The main function of the micro inverter is to convert the direct current output from of the solar energy to the alternating current through a small converter.Because of the wide application of the distributed solar power generation system,each solar module needs to match with inverter and converter modules,and each solar module can implement grid-connected power supply independently.The advantage of the micro inverter is that the maximum power point tracking can be used for each solar module,which can maintain the overall output power of the system.However,due to the the power imbalance existed in inverter,the output of solar energy needs to parallel decoupling capacitors with large capacitance.Currently,the decoupling capacitors on the market are electrolytic capacitors with short life and low power density,which will cause the decline of the durability and the service life.With simple structure,the interleaved flyback circuit can reduce the volume of the filter and improve the power density,which meets the requirements of the long lifespan and small size of the micro inverter.This paper selects the interleaved flyback circuit topology and analyzes the working principle and control method of this topology.Moreover,the main components of the circuit and the auxiliary circuit which is necessary in the control are also been designed and selected.In addition,this paper analyzes the problem of power imbalance in the DC/AC transform and points out the shortcomings of IIaralleling electrolytic capacitors with large capacitance.Based on it,this paper also discusses how to reduce the capacitance of decoupling capacitors.Besides,in the circuit,the decoupling circuit can used to reduce the capacitance value,and the working principle and control method of the ducoupling circuit are analyze.Finally,according to the results of theoretical analysis,the circuit simulation verifies the correctness of the theoretical analysis,and built a 400 W experimental prototype is builted and experimental results are give to verify the correctness of the theory analysis.