Agrid-connected Strategy Base On OCC For Variable Speed Constant Frequency Wind Power System

Wind power has an extremely positive role to solve the global energy crisis and environmental pollution problems; the excitation converter plays an important role in the grid-connected control of wind power generation system. This paper is based on the variable- speed constant-frequency wind power generation system and uses dual PWM converter based on One-Cycle Control as the Excitation regulator of Doubly-Fed Induction Generator (DFIG), then the theoretical of no-load grid-connection is studied.The operation control modes of wind power technology are firstly generalized, and the significances of variable-speed constant-frequency wind power generation are summarized. Then several common excitation converters and their characteristics are introduced. According to the special requirements of variable-speed constant-frequency wind power generation, the dual PWM converter based on One-Cycle Control is choused.The principles of grid side converter and rotor side converter are analysis in detail, One-cycle control strategy and the PWM converter control laws are combination, and the fuzzy PID controller is introduced to the grid side converter control process. Simulation results prove the dual-PWM converters based on OCC can guarantee the DC output voltage stability and modulate the field current, achieving good control effect.The working principle of DFIG and no-load grid-connection control technique are analysis, the mathematical model of DFIG is established. The dual PWM converter based on One-cycle control is applied to no-load grid-connection control system, through the pulse width modulation using One-cycle control, the rotor excitation current is controlled, and the output voltage of stator side is regulated. When the information of output voltage is the same as the information of grid voltage, the control objective is achieved. Finally the circuit model is established using Matlab and experiment results which are based on hardware-in-the-loop simulation platform for DFIG wind power generation system based on OCC via dSPACE indicates the control strategy is correction and effective.