Heliyon (Mar 2024)
Analysis and experimental verification of efficiency parameters affecting inductively coupled wireless power transfer systems
Abstract
Wireless power transfer (WPT) provides a safe and independent transfer of energy without the constraints of cables. The most suitable method for wireless charging of Electric Vehicles (EVs) is magnetic resonance coupling, which transfers energy in the near field. In this study, the effect of quality factor on the wireless charging system of an EV is investigated. After determining 85 kHz frequency, 20 kW power and 150 mm inter-coil distance, the design of the WPT system was realised according to the quality factor. It was observed that the quality factor affects the efficiency, critical air gap and voltage stress on capacitors. As the quality factor increases, the critical air gap increases and longer distances can be transmitted efficiently. However, as this factor increases, the voltage stress on the capacitors also increases. In this study, the critical air gap was determined according to the quality factor. Although high quality factor increases efficiency at high air gaps, it decreases efficiency in applications where air gaps are close. In fact, increasing the quality factor by increasing the inductance means increasing the internal resistance and this has been observed to reduce the maximum efficiency. In this study, the effects of Q factor on transmission power and transmission efficiency are investigated through experimental study and simulation.
