Design and Optimization of Ground-Side Power Transmitting Coil Parameters for EV Dynamic Wireless Charging System

This paper proposes a ground-side power transmitting coil parameter design method that takes the length of the transmitting coil as an optimization target, which takes into account the driving speed of EV (Electrical Vehicle), the EV's power consumption per kilometer, the coil energy loss and the system charging efficiency. The system uses a long-track transmitting coil, rectangular receiving coil, and LCC-S resonance compensation topology. First, the charging power and energy transmission efficiency are calculated. Based on the condition that the dynamic wireless charging power within 1km is not less than the EV's power consumption per kilometer, the lower limit of the charging power is determined. Secondly, the minimum value of transmitting coil current is inferred from the peak value of the charging power, the corresponding compensation inductance and transmitting coil wire diameter are further obtained, then the relationship between the system efficiency, the load resistance and the transmitting coil length is calculated. Under the condition that the charging efficiency is not less than 80%, the selection range of the transmitting coil's length and the load resistance value is initially determined, which further refined by combining the curve of the charging power with the load resistance value and “2 second principle”. Finally, aiming at segmenting a road section of 1 km in integers with the least number of transmitting coil segments, the number of transmitting coil segments and coil length that simultaneously meet the economic requirements for coil laying and system efficiency are determined. Finally, the feasibility of the above transmitting coil parameter design method is verified through experiment. The parameter design and optimization method of ground-side power transmitting coil of EV DWPT charging system proposed in this paper provides a reference for the design of the power transmitting coil length of EV DWPT charging system in the high-speed driving scene.