A Bi-Directional Inductive Power Transfer System with Zero Voltage Switching and Unity Power Factor for a Wide Operating Range

A conventional bi-directional inductive power transfer (Bd-IPT) system is required to accommodate a wide range of loads due to variations in the magnetic coupling factor and battery voltage of electric vehicles (EVs). To address this challenge, the system adjusts both internal and relative phase shifts of the H-Bridge converter to achieve the desired power transfer. However, altering the internal phase shift may lead to a loss of zero-voltage switching (ZVS) in the converters, while changing the relative phase shift can introduce reactive power into the system, resulting in increased losses in the coil and the converter. This article presents a novel Bd-IPT system that utilizes an integrated boost multilevel converter (IBMC) with a digitised modulation scheme. The primary objectives of the proposed Bd-IPT system are to maintain the desired power transfer, operate both the primary and secondary converters within the ZVS range, and achieve zero reactive power for a wide range of loading conditions. Additionally, the article compares the efficiency and cost of the proposed Bd-IPT system to a conventional IPT system.