Magnetizer Optimization of DD Type Coils for EV Wireless Charging System

In order to increase the mutual coefficient between wireless charging coils of electric vehicles (EVs) and to improve the charging efficiency, the effect of magnetizer in wireless charging system is analyzed by using the circuit theory. Based on double D (DD) coils, flat-type magnetizer structure is simulated and optimized by using the three-dimensional finite-element analysis tool ANSYS MAXWELL. A new type of H-type magnetizer structure is proposed in this paper. And the magnetic flux density distribution diagrams on the surfaces of flat-type magnetizer and H-type magnetizer at horizontal offsets of 0 mm, 100 mm and 200 mm are obtained and compared. Simulation results show that: H-type magnetizer has better performance in the mutual coefficient and coupling intensity and can reduce volume by 40%, compared with flat-type magnetizer.