Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 101 === This thesis presents a single-stage three-phase CCM wind-power converter. In order to achieve both maximum-power-point-tracking (MPPT) and three-phase power-factor-correction (PFC) mechanisms, two stages are employed in the conventional wind energy conversion system (WECS). However, the two-stage system results in some drawbacks, including larger volume, more components, higher circuit cost, more complicated control scheme and lower system efficiency. Therefore, the proposed converter of this thesis is developed to avoid these problems and increase the electromechanical conversion efficiency of the wind turbine generator (WTG), the MPPT and three-phase PFC mechanisms are employed simultaneously.
In the proposed circuit, a three-phase PFC converter and an average-current-mode control (ACMC) scheme are utilized to improve the power factor of the converter for the WEC. Besides, according to the characteristics of the WTG, the output voltage, current, and power of the WTG can be operated at MPP for each wind speed by using the ACMC scheme and subtracting amplifier.
In this thesis, a wind turbine emulator (WTE) is used as the AC source for the proposed circuit with the emulated wind speed ranging from 5m/s to 9m/s. The lowest and highest powers at MPP of the WTE are 185W and 1079W, respectively. Finally, a prototype circuit of the single-stage three-phase CCM wind-power converter is built to verify the performances using MPPT and three-phase PFC mechanisms.
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