Comparison of Magnetic Couplers for IPT-Based EV Charging Using Multi-Objective Optimization

Abstract

Inductive power transfer (IPT) is becoming increasingly popular in stationary electric vehicle (EV) charging systems. In this paper, the influence of the different IPT coupler geometries on the performance factors such as efficiency, power density, misalignment tolerance, and stray field is studied. Four different coupler topologies, namely the circular, rectangular, double-D (DD-DD), and the double-D transmitter with double-D-quadrature receiver (DD-DDQ) are considered in this study. The electromagnetic behavior of the couplers is modeled using three-dimensional finiteelement method, which is validated by experiments on a laboratory prototype. A multi-objective optimization (MOO) framework is developed to analyze the Pareto tradeoffs between conflicting performance metrics for the couplers. Optimization results depict that the circular topology performs best among the selected topologies regarding higher coupling coefficient, and efficiency for similar active mass and coupler area. Circular and rectangular couplers perform better than the polarized couplers like DD-DD and DD-DDQ regarding stray field exposure in both vertical and lateral direction of the coupler position in the EV. However, polarized couplers show more tolerance toward misalignment compared to circular and rectangular couplers. Thus, this study provides information regarding the specific strengths and weaknesses of different coupler topologies, which can be used during the initial design phase.

An LCC-SP Compensated Inductive Power Transfer System and Design Considerations for Enhancing Misalignment Tolerance

“…When the positions of the two coils make k equal to k0, the output current Iab is the same as that of (10). The output current increases linearly when k increases from 0 to 1, which means great output current fluctuation.…”

Design Optimization of Inductive Power Transfer Systems Considering Bifurcation and Equivalent AC Resistance for Spiral Coils

“…Step 6: The dc resistance of primary and secondary coils are obtained using equations (17) up to (19). Using the proposed equations (20) and (27) up to (31), the AC resistance is calculated.…”

“…AC resistance of a coil is significantly larger than DC resistance under higher operating frequencies [17]- [20]. Furthermore, previous works have no discussion about ZVS operating area and avoid bifurcation phenomenon in their designs [20]- [23], which have less generality.…”

Transmitter Side Control of a Wireless EV Charger Employing IoT

“…To achieve this, in this work the transmission of the appropriate information of the receiver side is proposed to be implemented by employing IoT. As such, the coupling coefficient (and hence the mutual inductance of the coils) can be calculated on- fly by the proposed controller, by acquisitioning both the transmitter and the receiver side voltage and current measurements [31]. As depicted in Fig.…”