| Summary: | 碩士 === 國立高雄應用科技大學 === 電機工程系 === 98 === Three-phase four-wire distribution power systems have been widely applied in office buildings and manufacturing-office buildings to supply single-phase or three-phase loads. The uninterruptible power supply (UPS) is generally applied to supply the high quality power to the computer and precise equipment. In this thesis, three-phase input single-phase output UPS, composed of three-phase AC-DC power converter, battery set and single-phase DC-AC inverter, is addressed. Several circuit topologies and control methods, applied for the power factor correction, are analyzed, and the advanced two switches based power factor correction circuit with a new power factor correction method is proposed and implemented in the three-phase AC-DC power converter. The three-phase input currents of proposed three-phase AC-DC power converter are balanced, sinusoidal and in phase with the three-phase utility voltages so as to perform the unity power factor. The single-phase DC-AC inverter is configured by a diode-clamped three-level inverter to generate a high quality voltage to the load regardless the utility is normal or not. Finally, the computer simulation is made to verify the performance of proposed UPS. The simulation results show the performance of proposed three-phase input single-phase output UPS is as expected.
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