A Novel Integrated Boost Modular Multilevel Converter for High Power Wireless EV Charging

Traditional H-bridge based Wireless Power Transfer (WPT) systems used in electric vehicle (EV) charging possess many challenges in high power applications such as fast charging and dynamic charging. Although multilevel converters are suitable for high power applications, existing multilevel converter based WPT systems have many drawbacks such as the need for independent DC sources and undesired circulating currents. As a solution, this paper proposes a novel Integrated Boost Modular Multilevel Converter (IB-MMC) suitable for high power WPT applications. The IB-MMC consists of series connected half-bridge (or full-bridge) sub-modules (SMs) forming each arm of the converter where the DC supply is connected to each arm through a boost inductor. This unique circuit configuration enables the IB-MMC to produce a low THD staircase modulated voltage waveform with a significantly higher amplitude without any circulating currents. A mathematical model of an IB-MMC based WPT system is presented and a simple control technique is discussed. Simulation results of an 11 kW IB-MMC with 4 SMs are presented to demonstrate its ability to produce a 5-level staircase voltage at 85 kHz with 16% THD. The advantages of the proposed IB-MMC technology are demonstrated by comparing it with state-of-the-art H-bridge based WPT systems.