Inductive Wireless Charging for Electric Vehicles: Design Calculations and Power Loss Estimation

Inductive wireless charging technology for electric vehicles (EVs) offers a contactless and efficient method of power transfer. By eliminating the need for physical connectors, it enhances user convenience and reduces maintenance. However, optimizing system parameters such as coil alignment, resonant frequency, and coupling efficiency is crucial to minimize power losses and maximize overall efficiency. This paper presents a detailed design approach for an inductive wireless charging system, including theoretical modelling, power transfer calculations, and power loss estimation. The paper begins with an overview of the wireless charging system architecture, covering the key components such as the transmitter coil, receiver coil, resonant circuit, and power electronics. The inductive power transfer (IPT) model is developed to analyze mutual inductance, coupling coefficient, and resonant frequency. Performance calculations are conducted to determine power transfer efficiency, taking into account factors such as coil misalignment, air gap variations, and core material selection. Additionally, comprehensive power loss estimation is presented, including ohmic losses in the coil windings, eddy current losses in conductive materials, and core losses in ferrite materials. The total power losses are calculated based on real-world operating conditions, and optimization strategies are proposed to improve system performance. By implementing enhanced coil design, resonant compensation, and power electronics optimization, system efficiency can exceed 90%.This study provides valuable insights into the design and optimization of inductive wireless charging stations for EVs, contributing to advancements in sustainable and efficient charging solutions.