本文旨在開發兩組三相變頻器的並聯運轉之控制技術，並應用於三相市電併網及獨立供電。並聯運轉的優點為提高功率及運轉的可靠度，不僅可提供直流微電網的功率，亦可將直流側再生能源的功率回饋至市電側，以達到買、賣電的功能；另當市電停電或故障，可提供三相交流電壓電源供給交流負載使用。在獨立供電的控制策略方面，其中一模組採用交流側電壓回授，配合同步旋轉座標系統轉換技術以完成交直軸電壓閉迴路控制，另一模組可作分配及電流的控制，不僅可提供負載需求功率，亦可降低交流輸出電壓調整率。在三相市電併網的控制策略，採用交流側電壓及電流回授，以完成電壓角位置偵測，交直軸電流閉迴路控制，其實功率可程控制。同時具有直流電壓閉迴路控制策略，亦可穩定直流側電壓以作為直流電網的電壓調節用。
本文以32位元數位控制器(DSP,TMS320F28335)為核心，完成單模組換流器的實體製作。市電併網及獨立供電的控制策略皆由C語言完成。每個模組皆由通信介面CAN-bus與個人電腦作通信，並由個人電腦的顯示器監視電壓、電流、功率狀態，及作功率命令及操作模式的設定。文中亦提出三相110V,1kVA的單模組換流器及兩組並聯操作實測，以驗證控制策略的可行性。本文已完成雙模組市電併網及獨立供電之並聯操作，其市電併網操作於功率2kW時，效率為95%，電流總諧波失真為4.38%，獨立運轉操作於1kW時，效率為96%，其電壓總諧波失真為1.89%，電流總諧波失真為4.16%。

The thesis focuses on developing the control technology of parallel operations of multiple three-phase inverters and applies such technology to three-phase grid-connected power system as well as standalone AC power supply. The advantages of parallel operation increase the capacity and reliability of operation.The grid-connected inverters are capable of switching power flow bidirectionally, supplying DC micro-grid-connected power, and transmitting renewable energy on the DC side to the grid-connected power system.By doing so, buying and selling electricity can be achieved. Moreover, the three-phase AC voltage source is able to supply power to the AC load while the utility power fails. As for the control strategy of the standalone power supply, one of the inverter modules accomplishes the closed-loop control of q-d axis voltages by adopting synchronous frame transformation and AC voltages feedback as well. Another inverter module can be used to control the real power or average-current-sharing. Accordingly, the power which the load requires can be supplied while the rate of AC output voltage regulation can be reduced as well. The control strategy of grid-connected power system adopts the feedback of voltages and currents on the AC side to achieve the voltage phase angle detection, the q-d axis current closed-loop control, the controllable real power with software. In addition, this technology has a DC voltage closed-loop control strategy which stabilizes the DC voltage which is used to regulate the DC grid-connected voltage.
This thesis used a 32-bits digital controller as a control core to implement one inverter module. The control strategy of grid-connected power and standalone system will be accomplished by programming with C language. Each inverter module will communicate with a personal computer(PC) via CAN-bus and will be displayed on a monitor of the PC not only to show the simultaneous status of voltage, current and power, but also to execute power commands as well as setting up the operation modes. The three-phase 110V 1kVA inverter was built. Experimental result was provided from two parallel-connected inverters, which verifies the validity of the proposed control strategy.

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