Research And Design Of Photovoltaic Inverter Based On Soft-switch PWM Technology

In recent years, the photovoltaic technology has been attended increased and applied wide with the global traditional energy crisis intensifies. And the inverter is an important component in photovoltaic system. It is a direct decision of the power generation efficiency and power quality. At present, photovoltaic industry is the initial stage in China. The performance of inverter is also not ideal. All aspects of performance are to be further improved. In this paper, author analyses and simulates the circuit structure of several soft-switch inverter of the present . And then author designs the inverter by using the " full-bridge conversion + High-frequency boost + full-bridge inverter" design proposal ,which to obtain high-performance inverter.The soft-switch technology is studied on the paper in first. For shortcomings and deficiencies of hard-switch, author analyses the merits of soft-switching technology in this paper . Author analyses and simulates the circuit structure of several soft-switch inverter of the present . The superiority of soft-switch technology is verified through the simulation. It provides a certain reference value for the soft-switch technology into the actual engineering practice.Finally, the thesis is also carried out the actual engineering design to the inverter power supply. The inverter system is divided into four modules to be design in the paper . (1) the part of DC / DC step-up , after the subject analyses and compares several circuit structure , it uses full-bridge conversion circuit to design. The paper discusses the design of high-frequency transformer, the choice of switch and components of rectifier circuit to be confirmed in detail; (2)the part of DC / AC inverse, the subjects uses full-bridge inverter circuit by comparison of several circuits .It discusses the choice of switch and design of filter circuit in detail; (3) the part of DC / DC control circuit, the subject controls switch with SG3525 chip; (4)the part of DC / AC control circuit, the subject uses TMS320F2812 chip .It controls switch, generate SPWM wave .And it has been used a master chip to develop protection circuit and control circuit of the entire inverter system.The design of the inverter power supply in improved resonance technology to achieve soft switching on the article. Through experimental verification, the technology have very good results to reduce switching loss and improve inverter efficiency. It provides a theoretical basis and reference value for the design and development of photovoltaic inverter in the future.