Design Considerations of a Single Stage LLC Battery Charger

Conference: PCIM Europe 2019 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
05/07/2019 - 05/09/2019 at Nürnberg, Deutschland

Proceedings: PCIM Europe 2019

Pages: 7Language: englishTyp: PDF

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Authors:
Zhou, Wenqi (Robert Bosch GmbH, Germany)
Wattenberg, Martin (Robert Bosch Center for Power Electronics, Germany)
Schwalbe, Ulf (Fulda University of Applied Sciences, Germany)

Abstract:
Usually battery chargers have two stages and DC charging current is considered to be necessary for a proper charging. To decrease the charger volume, a single stage LLC battery charger is investigated in this paper. PFC stage is eliminated, therefore no bulky capacitor is necessary any more, and battery is charged with a sinusoidal-like charging current. However, previous studies show that, such a pulsating charging current has only minimal impact on battery life and efficiency. Design considerations of the resonant tank and optimal transformer design are presented. A 360W single stage LLC converter prototype for e-bike charger achieves a power factor of 0.98, efficiency of 0.93 and power density of 1.8kW/dm3.