Frequency hopping wireless power transfer within the SAE J2954 operating frequency bandwidth for charging electric vehicles

Abstract

Wireless Power Transfer (WPT) is a means of transferring electric power through a magnetic or electric field via an airgap. This technology has resulted to the recent independence of plug in systems to charge equipment. The propagation of electric vehicles (EV) necessitates advancements in WPT technologies to enhance security, efficiency and reduced EV dwell time for charging. It is expected that wireless EV chargers will be installed in hospitals, railway and other non-domestic car parks which has equipment that emits electromagnetic waves thus, the potential to interfere with the wireless charging sessions. Conversely, the operation of the wireless EV chargers, if not shielded, has similar potential in its electromagnetic field strength to negatively impact the operation of near field equipment. Consequently, this research has been undertaken to develop an engineering solution to address these issues. Sparse research has been undertaken in the field of immunization of WPT power signals. Most studies focused on the vulnerability of WPT as it operates at 85kHz which apparently can be a single point of failure as interference, spoofing, power theft, and jamming can severely impact its charging session. The few solutions propounded by the researchers have not been generally developed and implemented this may be due to the lack of urgency of this technology. In this research the Frequency Hopping (FH) technique was incorporated in the WPT power and control circuitry as a solution to the risks associated with a single operating frequency. This novel design intervention founded the FH Wireless Power Transfer (FHWPT). FHWPT was developed as a system to introduce resilience and redundant operating frequencies in the WPT. FH is an existing technology used in communications to send and receive messages securely. This scheme was adopted to enable the WPT to operate in environments where conditions e.g. radio frequency interferences, power theft and jamming are hostile towards the predominant operating frequency. This thesis demonstrates the feasibility of enabling FHWPT with key circuit modifications to existing WPT systems. It highlights the potential of FH to enhance security and operational resilience in EV charging and covers system design, implementation, and prototype development.