| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 101 === A three-phase grid-connected inverter, which is capable of controlling real/reactive power via internet and achieving low-voltage ride through (LVRT) function, is proposed in this thesis. By adopting the strategy of direct quadrature transformation to control the three-phase current injected into the utility line, active/reactive power control can be achieved successfully by using the three-phase three-wire voltage source inverter. An EIA-485 communication interface is also developed for users to give the active/reactive power commend via internet.
Besides, in order to achieve the LVRT function, a new method is proposed to calculate the accurate grid voltage without using the conventional phase-locked loop (PLL) so that the three-phase inverter can remain connecting to the utility line during the most severe voltage drop scenario. The proposed strategy also allows the three-phase inverter to maintain grid-connected operation during the voltage recovery period.
Finally, experimental results measured from a prototype circuit are presented to verify the performances of the proposed three-phase grid-connected inverter with real/reactive power and LVRT capability.
Keywords：Communication through internet、Reactive power、LVRT(Low-Voltage Ride through)、Grid-connected、Three-phase inverter、EIA-485、Grid voltage calculation
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