Grid-Side Converter Control and Wind Turbine Emulator in Direct Drive Wind Power System
|School||Harbin Institute of Technology|
|Keywords||permanent magnetic direct-drive wind power generation PWM converter vector control based on grid voltage orientation three-phase software PLL soft start wind turbine emulator|
Wind energy is the world’s fastest growing renewable energy source in recent years, and it has drawn worldwide attention. Due to high efficiency, simple topology and stable operation, variable speed constant frequency (VSCF) direct-drive wind power generation system using permanent magnet synchronous generator (PMSG) is the development trend and one of the focuses of wind power generation system research.Firstly, PWM converter is selected to be the power converter of direct-drive wind power generation system based on PMSG because the generator-side converter and grid-side converter can be controlled separately. The device parameters of main circuit of PWM converter are optimal designed. Software framework, structure and functional modules are designed after choosing appropriate DSP type.Secondly, successful control strategy of grid-side PWM converter is the key technology for direct-drive wind power generation system. Double closed loop control scheme of grid-side PWM converter based on PI regulator is designed and three phase software PLL is used in order to improve the accuracy of grid voltage orientation. Soft-start strategy is designed and implemented to minimize the rush current when the system starts.On the other hand, in the development of wind power generating system, the wind turbine emulator becomes more and more important because it can provide controllable wind turbine characteristics. Simplified mathematical model based on the CT-λcurve is constructed, the system structure and emulation method are analyzed, hardware and software are designed and implemented, and a laboratory set-up is built based on DC motor. Experimental results show that the wind turbine emulator is as good as expected.