Article: Hardware design and implementation for Class-E power amplifier for Qi compatible wireless power transfer for consumer electronics Journal: International Journal of Power Electronics (IJPELEC) 2025 Vol.21 No.4 pp.398 - 415 Abstract: This paper presents the design of a Class E power amplifier tailored for wireless power transfer applications, with an emphasis on achieving system compactness. The amplifier operates at a switching frequency of 100 kHz and delivers an output power of 15 W, conforming to Qi standards. A series-series topology was chosen for the wireless power transfer system. To achieve zero voltage switching (ZVS), the primary side was tuned to a frequency slightly lower than the switching frequency, eliminating the need for an additional inductor. This innovation results in a more compact and cost-effective system without compromising performance. To ensure effective power transfer, the secondary side was tuned to resonate at the switching frequency. Design calculations were validated using LTspice simulations and hardware implementations. This paper also evaluates the efficiency of the designed converter and provides an analysis of power loss. The proposed system is primarily intended for consumer electronics applications, such as cell phone chargers, offering a simplified and efficient solution. Inderscience Publishers - linking academia, business and industry through research

Title: Hardware design and implementation for Class-E power amplifier for Qi compatible wireless power transfer for consumer electronics

Authors: Avishek Munsi; Rohan Kumar; Kunwar Aditya

Addresses: Department of Electrical Engineering, Transportation Electrification Lab (T.E.L), IIT Jodhpur, Rajasthan, India ' Department of Electrical Engineering, Transportation Electrification Lab (T.E.L), IIT Jodhpur, Rajasthan, India ' Department of Electrical Engineering, Transportation Electrification Lab (T.E.L), IIT Jodhpur, Rajasthan, India

Abstract: This paper presents the design of a Class E power amplifier tailored for wireless power transfer applications, with an emphasis on achieving system compactness. The amplifier operates at a switching frequency of 100 kHz and delivers an output power of 15 W, conforming to Qi standards. A series-series topology was chosen for the wireless power transfer system. To achieve zero voltage switching (ZVS), the primary side was tuned to a frequency slightly lower than the switching frequency, eliminating the need for an additional inductor. This innovation results in a more compact and cost-effective system without compromising performance. To ensure effective power transfer, the secondary side was tuned to resonate at the switching frequency. Design calculations were validated using LTspice simulations and hardware implementations. This paper also evaluates the efficiency of the designed converter and provides an analysis of power loss. The proposed system is primarily intended for consumer electronics applications, such as cell phone chargers, offering a simplified and efficient solution.

Keywords: wireless power transfer; WPT; Class-E amplifier; battery charger; zero voltage switching; ZVS; Qi standard.

DOI: 10.1504/IJPELEC.2025.147344

International Journal of Power Electronics, 2025 Vol.21 No.4, pp.398 - 415

Received: 24 Sep 2024
Accepted: 24 Jan 2025
Published online: 14 Jul 2025 *

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Title: Hardware design and implementation for Class-E power amplifier for Qi compatible wireless power transfer for consumer electronics

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