| Summary: | 碩士 === 長庚大學 === 電機工程學系 === 99 === The purpose of the thesis is to develop a DSP-based grid-connected wind energy conversion system (WECS), capable of compensating the power factor and current harmonic for the wind-driven generator and the grid utility. The wind power is converted to the grid through a fully digital-controlled laboratory prototype which consists of a 1.5kW wind driven permanent magnet synchronous generator (PMSG), a three-phase switching rectifier, a push-pull converter, and a grid-tied single phase inverter. The three-phase switching rectifier is used to regulate the wind turbine speed such that the wind can influence the moving blade in an efficient way without causing turbulent vortex. The push-pull converter boosts the voltage generated by the switching rectifier so as to adapt the single-phase inverter to the voltage level of the grid utility. The grid-tied single phase inverter is mandatory to maintain the dc-link voltage in order to deliver the wind power to the grid utility. To refine the power quality for the PMSG and the grid utility, additional control loops including
reactive power compensator and active power filter are integrated into switching rectifier and single phase inverter. To achieve quick and accurate control in current response, a proportional-resonant (PR) current controller is adopted. The PR-controller is also advantageous to reduce the complexity in control design and the computation burden for the DSP microcontroller. The experimental results not only investigate the performance of the proposed WECS but also show that the refined power qualities such as the unity power factor, low total voltage harmonic distortion (<0.7%) and low total current harmonic distortion (<4.5%) at the grid utility fulfill the requirement stated in IEEE Std. 519.
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