Input Voltage Range Optimization of a High Power Wireless Power Transfer System for Constant Power Output

Designing wireless power transfer systems for high power energy transfer is challenging, especially when transferring constant power under misalignment and varying battery voltage. In systems with passive rectifiers, there are not many control parameters that can be adjusted to regulate the output. In order to maintain constant power under misalignment, common approaches normally require a large input voltage range. This results in either high cost for the active frontend or higher losses in the inverter due to increased hard switching. This work shows an optimization approach to transfer constant power in all alignment conditions by achieving the best possible efficiency while minimizing the input voltage range. An existing 50 kW wireless power transfer system is taken as a starting point for an optimization. The range minimization of the input voltage is achieved by modifying the compensation parameters of the LCC resonant network on the primary side. The optimization results are then shown and suitable solutions are compared to the standard resonant design.