Browsing by Author "Herpers, Christian"

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    Detection of misalignment and foreign objects in resonant capacitive power transfer
    (University of New Brunswick, 2023-10) Herpers, Christian; Rouse, Chris D.
    Wireless power transfer has gained interest in recent years due to the increase in the number of mobile electronic devices and systems needing to be charged. Capacitive power transfer (CPT) offers a low-cost option for medium- and high-power charging. To ensure safe and reliable power transfer, foreign objects and misalignments must be detected. Furthermore, exposure of living tissue to high electromagnetic fields (EMFs) must be avoided. This work presents CPT detection methods for both lateral misalignment and foreign objects (FOs). Symmetries of capacitance matrices are studied to distinguish between types of misalignment and FOs. Results were generated via simulation and verified with measurements on a laboratory 13.56 MHz CPT link. FO detection also functions under lateral misalignment, is parameter-based, and is achieved without external circuitry or sensors. Results indicate the direction of lateral misalignment. EMF exposure was simulated to ensure kW-range power transmission while meeting international safety guidelines.
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    Lateral Misalignment and Foreign Object Detection in Resonant Capacitive Power Transfer
    (IEEE, 2023-08-22) Herpers, Christian; Rouse, Chris D.
    This paper proposes a method of detecting lateral misalignment and foreign objects in a resonant capacitive power transfer (RCPT) system. Foreign object detection (FOD) under misalignment is also considered. The method considers the admittance matrices associated with a practical RCPT link and leverages voltage measurements on the transmit-side for detection. To support this work, a 13.56MHz RCPT link in- corporating a six-plate structure was designed and built for electric vehicle charging applications. A matching simulation model was created and, when evaluating FOD, metallic and tissue-simulating foreign objects were added. Simulations, val- idated by measurements, show that a lateral misalignment of up to 170mm can be identified, including the direction of misalignment. FOD simulations indicate a detection range of up to 380 mm, also including direction. Further simulations indicate that the detection range surpasses the distance at which the basic restrictions for electromagnetic field exposure would be exceeded. Additionally, simulation results show that foreign objects can be detected under misalignment. Thus, both lateral misalignment detection and FOD can be achieved without the use of external sensors. This work can help to advance the safety features of RCPT at minimal cost for important applications such as electric vehicle charging and electrified roadways.
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    Synchronous Rectification for High-Speed Resonant Wireless Power Transfer Under Variable Coupling and Load
    (IEEE, 2025) Herpers, Christian; MacMillan, Matthew; Belliveau, Ethan T.; Rouse, Chris D.
    A synchronous rectifier (SR) for efficient and compact wireless power transfer (WPT) in applications involving variable coupling, variable load, and lower voltages, e.g., 60 V or less, is presented. The proposed SR employs the load-independent class E topology and a relatively simple synchronization circuit based on a tuned delay line. Analytical, simulation, and experimental results are presented for SRs implemented in resonant capacitive power transfer systems operating at 13.56 and 27.12 MHz. Both systems exhibit load independence over transmission distance variations of ± 25% from nominal. At 13.56 MHz, 300 W is delivered with a dc-to-dc efficiency of approximately 81% at nominal coupling, which translates to an SR efficiency of 93%, and the system can deliver 220 W over the full coupling range. At 27.12 MHz, 150 W is delivered at a dc-to-dc efficiency of approximately 76% at nominal coupling, translating to an SR efficiency of 89%, and 110 W can be delivered over the full coupling range. The performance of the proposed SR for resonant WPT applications is very encouraging, particularly at 27.12 MHz