| At present, direct-drive technology is the development trend of wind power generation system (WPGS), but the electricity generated by direct-drive wind power generator has many problems, voltage amplitude and frequency is changing with wind speed, the power is also unstable. To solve these problems, this paper introduces a method adding power conversion device to the output terminal of wind power generator, to obtaining standard electricity. Modern power electronic technology and advanced control technology are used to analyze and design the device.In this paper, based on analysis the characteristic of direct-drive WPGS and other devices, the main circuit structure, which composed of three-phase full bridge rectifier, sepic chopper and single-phase full-bridge inverter, is presented. According to the steady analysis of different circuit parts, criterions for choosing inversion device's key parameters are obtained, and decide the circuit components for a 2kW device. Utilizing dynamic model of sepic chopper, which established by PWM switch model, the average current controller is designed using integrated control circuit UC3854. By inversion device's dynamic model, a current-voltage double closed-loop control system is designed through PI control and deadbeat theory.Special software MatLab/Simulink and Saber are used to simulate the circuit and control system, circuit parameters and controller were optimized. The simulation results indicate: the device's circuit structure is reasonable, control strategy is right, the output electricity meets the design requirement. Based on the design and simulation results, high performance digital signal processor TMS320LF2407A is adopted to develop the digital control system, which carried out closed-loop control and SPWM control for inverter, multi-function about choosing electric power channel, protecting device and disposing fault for inverter, in addition, friendly human machine interface is provided.
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