本文提出考慮不理想電源之三階二極體箝位整流器並設計一控制器改善輸入電流不理想情況，其中輸入不理想電源情況同時包含不平衡以及諧波成分。本文所提出之控制器加入且利用快速傅立葉轉換分析輸入交流電壓源，使控制器能夠在電路操作時分析出基波與諧波成分之振幅與相位，在此藉由快速傅立葉轉換所產生之三相理想電壓命令回授補償，使控制器能建立理想輸入電流命令以達到高電力品質之輸入電流，最終結果會透過功率因數、總諧波失真度以及電流不平衡度來計算顯示。在此三階二極體箝位整流器控制核心採用一基於數位訊號處理器之數位控制器來實現提出之控制策略，此控制策略包含上述之快速傅立葉轉換、單位功因控制器、輸出直流穩壓控制器、電流控制器以及正弦脈波寬度調變等控制。
回授上述之分析結果至提出之控制器中，透過電流控制迴圈建立三相輸入電流補償電流命令並控制其振幅大小。此外利用正弦脈波寬度調變產生開關切換訊號，如此以獲得經改善且可調之輸入交流電流，藉此改善當三階二極體箝位整流器工作於不理想之輸入電網電壓狀態時，所造成系統之輸入電流不理想與輸出直流側電容電壓漣波增大等問題。故最終整流器會以單位功因、低輸入電流不平衡度、低總諧波失真度及降低輸出電容電壓漣波之形式呈現。
本文使用MATLAB/SIMULINK模擬軟體進行系統模擬，並建立一直流輸出電壓為750伏特、輸出功率2千瓦、功率因數為0.99之三階二極體箝位整流器架構，使用數位訊號處理器TMS320F28069作為控制器進行試驗，藉此透過模擬與實測驗證其可行性。

In this thesis, a three-level diode clamped rectifier energized by non-ideal three-phase power source is studied to improve the line current quality. Both unbalance and harmonics consisted in the ac source are under considered. The ac voltage source is analyzed by Fast Fourier Transform (FFT) which is built in the proposed controller to achieve the on-line calculation of the magnitudes and phases of fundamental and harmonic composition. The three-phase fundamental components obtained from the FFT are used to generate the ideal line current command to achieve high quality line currents which will be evaluated by total harmonic distortion, power factor, and current unbalanced factor. A digital controller based on digital signal processor is adopted in the proposed three-level diode clamped rectifier to deal with the proposed controller which includes the following issues, the mentioned FFT, power factor controller, output dc voltage regulator controller, current controller, sinusoidal pulse width modulation(SPWM), and so on.
The above-mentioned analysis results will through the current control loop to generate the three-phase input current compensatory command and control input current magnitude. Afterwards, adopting SPWM to generate switch signal, in this way, it can obtain the improved and modulated three-phase input current. Consequently, the proposed control scheme can solve the problems like non-ideal input current and increased capacitance voltage ripple caused by the input grid voltage under the non-ideal conditions. Hence, the performance of converter will finally evaluate in terms of near unity power factor, low input current unbalance factor and total harmonic distortion (THD) and reduced ripple factor of capacitance voltage.
The control scheme of this thesis using MATLAB/SIMULINK simulation software to prove, the experiment establishes a 750VDC/2kW three-level NPC rectifier and employ DSP TMS320F28069 as central controller to implementation. Simulation and experiment results shows in this thesis.

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