Minimizing Primary Current Based on Asymmetric Parameter Design Method under Wide Load Range and Variable Coupling Condition in Inductive Power Transfer Systems

To minimize primary current and enhance the misalignment tolerance of inductive power transfer systems under wide load range, this paper proposes an asymmetric parameter design method in the series-parallel (S-P) compensated topology with constant current (CC) output. The asymmetric parameters include asymmetric power transfer ratio and asymmetric compensation factor, which aims to redistribute the zeros and poles of system. With this asymmetric parameter design method, the IPT system can be made to achieve an asymmetric and monotonic power characteristic, as well as an input impedance angle that is insensitive to coupling and to load. Meanwhile, global ZVS conditions for primary inverter are always ensured. The experimental results show that the variation in primary current is 10% at rated load within the coupling coefficient range of 0.2~0.3.