A high-frequency link ac-ac converter for contactless power supply system in parking tower

This paper proposes a new concept for a contactless power supply system (CPS) in a mechanical multi-level parking tower for plug-in hybrid vehicles (PHVs) and electric vehicles (EVs). In recent years, PHVs and EVs have been commercialized as low environmental impact vehicles, and the demand for such vehicles is spreading rapidly. To cater to this increasing demand of PHVs and EVs, battery charging systems in the parking tower are necessary. Most multi-level parking towers have movable parking pallets that are electrically isolated from the building side. Because of the poor positional accuracy of the movable pallets, a contactless power transmission system between the utility grid in the building and the movable pallet is necessary. As for the CPS in the parking tower, a power conversion stage from commercial AC to high-frequency AC is necessary for size reduction. In general, such a power conversion system consists of power factor correction (PFC) converters and high-frequency inverters. Therefore, two or more conversion stages are necessary, which increases the power losses and cost. In this paper, a simple circuit configuration of a high-frequency link AC-AC converter for a CPS in a parking tower is proposed. The proposed high-frequency link AC-AC converter can directly convert commercial AC to high-frequency AC (HFAC) and HFAC to commercial AC again. Experiments are performed to demonstrate the validity of the proposed CPS. The proposed CPS is found to have a coupling coefficient of 0.75 for a contact-less transformer with a 10mm gap, and an efficiency of 86% can be achieved.