Research On Grid-connected Inverter Of Wind Power Generation

In 21 st century, new energy was researched for by the different countries all over the world, because the human societies develop quickly and the conventional energy can not satisfied the increasing need. With the requirement and development of low carbon economy construction, new energy generation technology became the present hot study issue. The percentage of new energy generation capacity in energy generation capacity was increasing year by year. The structure of the world energy was beginning to be changed. The wind power generation technology was one of the superior and had better development prospect forms of exploit of new energy in new energy electricity generation mode. So it is important and urgent to study and exploit the wind power generation technology.In this paper the grid-connected inverter of wind power generation was studied on the background of the wind power generation technology. Wind power generation technology has its own specific feature and advantage. All kinds of wind generator sets were analyzed, and then the direct-drive permanent magnet synchronous generator (PMSG) sets were selected as the object of study. This kind generator was on behalf of the future development direction of wind power generating set. The electricity generated by direct-driver permanent magnet synchronous generator in the mode of variable speed constant frequency (VSCF). The permanent magnet synchronous generator has superior characteristics in AC-DC-AC wind power generation system, so AC-DC-AC wind power generation system was used in this subject. The converting program of direct-drive system was various and flexible. At last, uncontrollable rectification and boost circuit and PWM voltage source inverter was chose as the AC-DC-AC converting program after comprehensive comparison among various converting program. The grid-connected inverter was various and its performance is different. The performance requirement is different on different occasion. In this paper instantaneous tracking current technology was used among various control strategies. In this method, the grid-connected current was taken as the command signal and inverter output current was taken as the feedback signal, the switch device was whether open or closed depending on the results of instantaneous comparison between them. So the inverter output current can dynamically track electricity grid voltage.The principles and structure of wind turbine, permanent magnet synchronous generator and grid-connected inverter were also analyzed and their math models were built. The simulation model of the whole wind power system was created in MATLAB/simulink software, and then it simulated under the condition of the device parameters and simulation parameters were set. This method was testified correctly and flexibly by analyzing the simulate result. Finally, the hardware and software were designed on the basic of DSP control technology. The TMS320F2818 chip was taken as the core of the converting control system. PWM pulse was generated by the PWM circuit and compare unit in event manger (EV) of the chip, the PWM pulse controlled the switch device open or closed. Phase locked loop (PLL) technology was used to make the frequency and phase of inverter output current in agreement with the frequency and phase of electricity grid voltage.