| Summary: | 碩士 === 國立臺北科技大學 === 電機工程系研究所 === 100 === This paper presents a new electrolytic capacitor-less and single-stage controlled three-phase battery charger with electrical isolation to provide wide-range output voltage for EV applications. To achieve this, a three-phase rectifier cascaded by a current-feed isolated buck-boost converter is proposed to yield DC voltage output and eliminate the bulk electrolytic capacitor installed behind the rectifier. Therefore, the lifetime of charger can be dramatically extended. Duo to without bulk electrolytic capacitor, there exists large ripple voltage at the output of three-phase rectifier. A design procedure of the controller with high rejection for voltage disturbance is developed to mitigate the current and voltage ripples for charging battery. Besides, the power factor compared to traditional rectifier is improved by the proposed single-stage topology simultaneously. Due to ZVS in light load and single stage switching architecture for the proposed charger, the efficiency is increased.
Experimental results derived from the DSP-based controlled charger will be presented. The charger rating is 4 kW and output voltage is from 50V to 400V. It will be shown that the output current and voltage ripple is reduced significantly without any electrolytic capacitors in the proposed charger. It will also be demonstrated that the efficiency is nearly 96% and the power factor is also improved at rated load compared that for rectifier. These experimental results therefore confirm the superb performance of the proposed topology and control techniques.
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