A Control Strategy for Achieving Constant Voltage Output with an Extensive ZVS Operating Range in Bidirectional Wireless EV Charging Systems

• Published in: Energies (Basel) 2024-04, Vol.17 (8), p.1819
• Main Authors: Li, Guangyao, Chen, Yafei, Zhang, Hailong, Xie, Junchen, Jo, Seungjin, Kim, Dong-Hee
• Format: Article
• Language: English
• Subjects: battery charging; bidirectional inductive power transfer (BIPT); constant-voltage output (CVO); Efficiency; Electric vehicles; triple-phase-shift control (TPSC); zero-voltage switching (ZVS)
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en17081819

Variations in the coupling coefficient of loosely coupled transformers and dynamic loads have a significant impact on the overall performance of bidirectional inductive power transfer (BIPT) systems. However, a wide range of load and coupling coefficient variations are common in the actual charging process, which may cause the converter on both sides to operate in a hard switching state, resulting in switching noise, reduced efficiency, and potential safety concerns. In this paper, a triple-phase-shift control (TPSC) strategy is proposed to study the zero-voltage switching (ZVS) operating range and constant-voltage output (CVO) characteristics of the double-side-LCC (DS-LCC) topology. To ensure a CVO over the wide range of coupling coefficient variations, a dual-phase-shift control is introduced for AC voltage matching. Based on this, the third phase-shift angle control between the converters on both sides is introduced to ensure the ZVS realization. Meanwhile, the time-domain model is developed to analyze the rationality of the proposed third phase-shift angle and the ZVS operating range. Finally, the effectiveness of the proposed TPSC strategy is validated through a 1.5 kW experimental prototype with an air gap of 100–150 mm.