Detuned Dual-Frequency Compensation for Wide Misalignment Tolerance in Inductive Power Transfer Systems

Abstract

In inductive power transfer systems, misalignment can lead to inconsistent output power. In this paper, a topology based on a primary-side detuned dual-frequency compensation circuit is proposed to provide consistent output characteristics over a wide misalignment range. The proposed topology constructs two intersecting power vs. coupling coefficient curves at two switching frequencies. The coupling coefficient range can be extended without increasing primary current and reactive power variability by changing the switching frequency at curve intersections. With this approach, the output power changes by only 10% over a 2.5:1 coupling coefficient range, and efficiency at low coupling can be improved. This means the proposed topology is more adaptive for misalignment. A 1500 W prototype has been prepared to verify the topology. Efficiency ranges from 86.8% to 94.5% over a coupling coefficient range from 0.14 to 0.35.