Coil-to-Coil Efficiency Optimization of Double-Sided LCC Topology for Electric Vehicle Inductive Chargers

This article presents an efficiency optimization of double-sided LCC compensation network for inductive power transfer systems. Compensation factors of the primary and secondary LCC circuit are defined and optimized analytically. The investigation shows that the secondary compensation factor krx highly influences the copper loss of the wireless coupler, whereas the primary compensation factor ktx should not be large in order to reduce the switching loss and conduction loss of the input inverter. With a proper selection of these compensation factors, it is possible to achieve a high and sustained efficiency over a wide range of load and misalignment. In order to demonstrate the feasibility and validity of the proposed method, a scaled-down prototype has been implemented with the operating frequency of 85 kHz, transfer gap of 170 mm, and misalignment of up to 100 mm. Experimental results show a good agreement with the theoretical analysis. The peak efficiency of the proposed system is 91.6% under the perfect alignment at the coupling coefficient of 0.172. The efficiency still remains at 86.37% even under 100-mm misalignment with the coupling coefficient of 0.123.

Automated summary

This article presents an efficiency optimization of a double-sided LCC compensation network for inductive power transfer systems. By defining and optimizing the compensation factors of the primary and secondary LCC circuit, a high and sustained efficiency over a wide range of load and misalignment is achieved. Experimental results show good agreement with theoretical analysis.