In this article, a design of bipolar nonsalient pole (BNSP) transmitter, which originates from motor theory, for high-power EV dynamic wireless power transfer (DWPT) system is proposed. To analyze and evaluate BNSP transmitter in aspect of principle, characteristic, and performance, the existing I-type, S-type, and N-type transmitters in DWPT application are classified as bipolar salient pole (BSP) transmitter, which establishes a reference for comparing. The design parameters and other contrast conditions of BNSP and BSP transmitters are given. Coupling flux and leakage flux of BNSP transmitter are analyzed by comparing the magnetic models and the finite-element models of BNSP and BSP transmitters. Based on the modular design in practical application, the sensitivity of coupling performance to the module gap in BNSP and BSP transmitters is analyzed and compared in simulation. All theoretical results are verified by contrast experiments. The maximum effective mutual inductance of BNSP transmitter is about 31.0% larger than that of BSP transmitter, and the efficiency of the system with output power of 10 kW is 93.5% with BNSP transmitter, about 2.4% higher than that with BSP transmitter. Besides, BNSP transmitter needs 5.9% shorter Litz wire and 53.1% smaller volume of cores, which makes it smaller in size.

In high-power dynamic wireless charging applications, the bipolar magnetic coupler is continuously developed due to its strong coupling ability. The latest proposed bipolar-non-salient-pole (BNSP) transmitter has shown significant improvements in performance, cost, and modularization. In this article, the efficiency of BNSP transmitter is further analyzed. A quantitative loss model is proposed to reduce the dependence of analysis on finite element simulation. The model of winding loss based on squared magnetic field analysis is introduced, and a concept of flat Litz winding design suitable for BNSP transmitter is proposed, which has lower loss and fewer nonideal loss factors. The model of core loss is established by the magnetic circuit model of BNSP transmitter and Steinmetz formula of the core material. In the experiment of 40 kW power, the proposed loss model is verified to describe loss components in BNSP transmitter accurately. Compared with bipolar-salient-pole transmitter of the same power level, BNSP transmitter is quite smaller in size and more compact in structure, with 28.2% shorter Litz wire and 27.6% smaller volume of cores. The rated efficiency of BNSP transmitter is 97.9%, and the dynamic efficiency of the magnetic coupler with BNSP transmitter is 94.4%–96.3%.

Dynamic wireless power transfer (DWPT) technology shows a vast development prospect for EV application, with advantages of reducing the demand for battery capacity and improving the user experience. However, the need to improve output performance leads to a challenge in receiver design with limited space and allowable load on the EV side. In this paper, a design of a dual-phase non-salient pole (NSP) receiver for the EV DWPT system with bipolar transmitter is proposed, aiming at providing a solution to the contradiction between reducing the volume or cost and improving the misalignment tolerance of the receiver. The coupling principle of the proposed receiver is analyzed. The structure parameters are optimized by the finite-element simulation method. Combined with specific design indexes, it is proven by comparison with the existing dual-phase receiver that the proposed receiver is 35.4% smaller in volume and needs 47.0% shorter wires. Moreover, the significant advantage of the proposed dual-phase NSP receiver in misalignment tolerance is verified by simulations and experimental comparisons.