A Z-Class LCC-P Compensated IPT System with a Reverse Coupled Compensation Inductor

Abstract

This digest proposes a cross-coupled LCC-P coil structure to improve the misalignment tolerance of a Z-class compatible inductive wireless power transfer system for electric vehicles (EVs) described in J2954. The standard specifies the misalignment distances in the x-y-z plane to which the system will be exposed. Misalignment induces large variations in coupling coefficients between the primary and secondary sides of the coupler, resulting in proportionally large power fluctuations. The design uses a reversed coupled filter inductor to improve misalignment performance. Compared to previously proposed designs, the proposed LCC-P topology offers good performance, while reducing the size and complexity of the vehicle side coupler. Additionally, all the coils in the coupler are unipolar, further reducing the overall system complexity. A prototype is designed and constructed to validate the proposed solution. Experiments have achieved 3kW power transfer with 95.8% efficiency.