| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 98 === Though renewable energy possesses the potential becoming one of most important power energy resources, its cost is high and efficiency is still low. The thesis intends to design and implement a grid-connected wind power conversion system with energy storage device. With simplified system architecture and improved maximum power point tracking (MPPT) control scheme, the proposed system has the advantages of lower cost and higher conversion efficiency. The controller used for the system is field programmable gate array (FPGA) program device developed in hardware description language (Verilog HDL). Depending on the characteristics of wind turbine generation, the MPPT control is conducted with the output power regulated by batteries. The structure of traditional bi-directional converter is improved by using only upper and lower power switches to achieve both original charging/discharging control purpose and replace the active power switch of the traditional boost converter. Not only the performance of the system is enhanced, but the cost can be reduced. Besides, a modified Three Point Weight Comparison (TPWC) Method is proposed in the thesis. It uses the variation rate of the power output as a weight-tuning control parameter. The maximum power curve can be tacked closer with higher tracking speed and efficiency than the original TPWC Method. The proposed system structure and control method have been verified on a practical 1.2kW wind-power conversion system. The experimental results show that the enhanced MPPT control and battery charging/discharging functions can be achieved for off-grid and on-grid operations, where real and reactive power output can be controlled according to system requirements.
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