The Design Of Single-phase PV Grid-connected Inverter

With the situation of energy resource crisis and the problem of circumstance pollution become more and more severity, exploitation and utilization the clean and regeneration energy resource is imperative. Solar energy is one of the most clean, practical and large scale regeneration energy resources. The whole world focuses on the use of photovoltaic (PV). The PV grid-connected system will be the main utilization of solar energy, so it will be developed rapidly. Furthermore, with the development of high-performance Digital Signal Processor (DSP) chip, it is possible that some most advanced control strategies can be used to the PV grid-connected system.Under this background, the dissertation deeply researches the PV grid-connected inverter, which is the hard core of the system, and uses the TMS320F2812 to control the system in order to transform the solor energy into electrical energy maximum. It has significance to reseach and experiment on the PV grid-connected system.By analyzing and comparing the structures and control strategies, two stages structure of PV grid-connected inverter and impoved fixed-swithing frequency SPWM current contol strategy is adopted in this dissertation. Then it analysises the PV array model and its output characteristics, and compares some usually used maximum power point tracking (MPPT) methods. Based on this, a MPPT method for our two stages structure inverter is proposed.By deep analysis and research, the design of the hardware and software of the whole system is introduced detailly: including the design of the main circuit of the system and its parameters, the design of the control cirtuit, the assign of the hardware resource and the flow chart of the software of the system.The experiment results demonstrate that the system can implement the contrlo scheme proposed in this dissertation perfectly and obtain the required performance of supplying power to grid perfectly. The control scheme is simple and doable. The system works stablization and has good performances.