Multi‐Objective Optimization of the Composite Shielding Layer for EV Wireless Charging Magnetic Couplers Using NSGA‐II

ABSTRACT

The research, development, and application of wireless charging technology for electric vehicles have emerged as a prominent research focus. However, traditional magnetic couplers have inherent defects: They are prone to magnetic saturation and inductance attenuation under high‐current operating conditions and suffer from the drawbacks of heavy weight and high brittleness that cause material cracking. To address the above issues, this paper proposes a magnetic coupler for electric vehicle wireless charging with a checkerboard‐structured composite magnetic shielding layer composed of flexible ferrite sheets and nanocrystalline ribbons and performs multi‐objective parametric optimization on its composite shielding layer structure in combination with the Non‐dominated Sorting Genetic Algorithm II (NSGA‐II). For the problem that ferromagnetic material loss compromises the efficiency of wireless charging systems, this paper investigates the influence regularities of the shape and thickness parameters of the magnetic shielding structure on system loss and inductance attenuation characteristics. Verified by simulations and experiments, the proposed magnetic coupler achieves a DC–DC transmission efficiency of 91.29% at an output power of 3.3 kW. Under the constant voltage mode with 330 V output, the maximum efficiency of the proposed shielding structure reaches 91.49%, which is approximately 1.27% higher than that of magnetic couplers equipped with traditional ferrite shielding layers, while reducing shielding layer volume by 18.7% and weight by 18.3%.