Single-stage Wireless Charger with High Power Factor Input

This paper proposes a single-stage Wireless-Power-Transfer (WPT) AC-DC converter with a high power factor. Compared to conventional two-stage WPT structures, the proposed single-stage wireless power transfer (SS-WPT) offers several advantages, including a low component count, interleaving effect, and soft switching commutation without electrolytic capacitors, leading to cost savings, high efficiency, and reliability. Unlike other existing SS-WPT systems that operate in discontinuous conduction mode (DCM), the proposed SS-WPT works in continuous conduction mode (CCM) with the help of interleaving, resulting in decreased core losses and input filter size. Additionally, a simple modulation technique is proposed with one control variable at the fixed switching frequency to regulate the output voltage and shape grid current simultaneously. Furthermore, the proposed modulation strategies also help reduce low-frequency ripples on the DC side without additional components, overcoming drawbacks of previous SS-WPT systems. A 500W SS-WPT laboratory prototype was built and tested to validate the effectiveness of the proposed integrated converter.