本論文旨就海潮流發電應用，研製一並聯變流器系統，透過並聯運轉方式擴充系統容量以因應負載需求且當任一系統故障時，其餘系統仍能持續運作，補足電力所需，提升整體系統運行之可靠度。本文以數位信號處理器為控制核心，建構具獨立供電模式與市電併聯模式之並聯變流器系統，利用結合電壓控制與電流控制之主僕式架構作為並聯運轉控制策略。電壓控制法回授交流電壓資訊，透過座標軸轉換概念於同步旋轉軸上進行電壓閉迴路控制，使系統於負載變動及輸入電壓變動情況下，皆可輸出穩定電壓。電流控制法回授交流電流資訊，透過同步旋轉座標轉換技術達到實虛功率之解耦，控制變流器系統追隨功率參考命令，達到均流及分流控制。另外，市電併聯之鎖相控制結合二階廣義積分正交信號產生器與同步信號檢測迴路取得市電及系統輸出電壓之相角資訊，進行輸出電流之同步控制。最後，本文以數位信號處理器實現變流器系統之並聯控制，完成獨立供電約1000 W及市電併聯約500 W之實驗來驗證其可行性。

In this thesis, the digital parallel-controlled inverter system is developed. The control strategy of the system is the combination of constant voltage control and constant current control which can let the system operate both in standalone and grid-connected mode. The constant voltage control strategy is realized by translating the output voltage signal from the stationary frame into the rotating frame so that sinusoidal voltage can be treated as dc value to be regulated. The constant current control strategy is implemented based on dq reference frame. By means of Park transformation, sinusoidal current can be represented as dc value, rotating synchronously at the detected frequency provided by phase-locked loop so that the active power and reactive power can be controlled separately by dq current command. Furthermore, with the use of the proposed PLL consist of the structure based on a second order generalized integrator (SOGI), the phase angle can be tracked precisely. Finally, the parallel-controlled inverter system is realized and experimental results show that the system can supply up to 1000 W in standalone mode and 500 W in grid-connected mode.

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