A comprehensive methodology to design an LCC/LCC compensated DD-DD coupler for efficiency maximization in IPT systems

Charging pads and compensation play a significant role in the inductive power charging system of electric vehicles. Its output power and efficiency depend on the precise magnetic design and the compensation tuning. In this connection, this paper develops a comprehensive strategy for designing LCC/LCC compensated Double D – Double D (DD) pads in a DC link capacitor-less bi-directional charging system to achieve the intended power output and coupling coefficient with maximized efficiency. By defining different dimensional attributes of the DD-DD structure, their effect on the magnetic and electrical performance parameters of the charger is assessed by varying the attributes’ values for the considered compensation parameters. The values of these attributes are optimized with the intent to steer the design towards the desired specifications. Subsequently, a methodology for selecting the optimal compensation variables for maximizing the efficiency at the desired power is established. Moreover, the work depicts the impact of output voltage on the optimal combination of the variables and the superiority of the developed formulation. To validate the proposed methodology, a 1 kW experimental prototype capable of bidirectional power transfer between the grid and a vehicle is developed. With a coupling coefficient of 0.3 and operating at 85 kHz, the developed prototype achieved an efficiency of 94 %.