本論文所提出三相變流器是藉由三組雙向轉換器所併合而成，各組雙向轉換器的輸出為交流正弦波疊加直流之脈動電壓，各組輸出相位差120°，各組雙向轉換器利用差動型式輸出，則在負載端即可得到三相交流正弦電壓。本文三相變流器控制策略是採取雙迴圈控制機制，藉以提升變流器的動態響應和穩定性。三相變流器系統之前級昇壓轉換器是採取雙組並聯輸出並在輸出端加入均流控制機制，使各組轉換器可平均分擔後級總輸出功率，藉由此控制機制以提升整體輸出功率，並且可提高三相變流器系統之穩定度與可靠度。最後建構一組輸出額定功率3kW的三相變流器系統，並且針對電阻性、電感性及電容性交流負載進行測試。系統前級雙組昇壓轉換器最高效率為96%，三相變流器最高效率為95%且總諧波失真低於3%，整體三相變流器系統最高效率為92%。

The purpose of the thesis is to study on three-phase inverter system with bidirectional converters. The three-phase inverter consists of three independent and symmetrical bidirectional converters. Each converter is drived by signals with 120 degree phase shift. The output voltage is sinusoidal with the same dc component. The output of inverter is in differential mode and the dc component disappears while only the sinusoidal voltage left on the load. The frond-end of three-phase inverter system is realized by boost converters in parallel with current sharing control strategy. The advantage is to raise output power capability and stability. A prototype 3kW three-phase inverter system is implemented and tested with the resistive load, inductive load and capacitive load. The maximum efficiency of boost converter is 96%. The maximum efficiency of three-phase inverter is 95% and THD is less than 3%. The maximum efficiency of overall system is 92%.

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