Dissertation Defense

Electromagnetic Model-Based Measurement, Sensing, and Detection for Wireless Power Transfer

Sung Yul Chu

Ensuring energy safety and security is vital, especially in transportation, pervasive in our daily lives. Wireless power transfer is an emerging technology for charging electric vehicles, which needs to be reasonable and safe to use. This dissertation aims to develop smart electromagnetic measurement and detection systems for wireless charging. Non-contact open-circuited sense coils sample the electromagnetic field to reconstruct the information needed for (i) transfer-power measurement, which imposes the cost for electrical losses to a transmitter (Tx) and receiver (Rx) based on physical heat dissipation, resulting in fair metering, and (ii) detection of foreign objects, fire hazards, for safe wireless charging.

Faraday coil transfer-power measurement (FC-TPM) is developed to measure transfer-power, which is the real power through the intervening space. The transfer-power can be reconstructed by measuring sense coil voltages with the geometric parameters, encapsulating the electromagnetic couplings between the Tx, Rx, and sense coils. FC-TPM was demonstrated with six sense coils in hardware accurately within 0.1% errors despite an Rx coil misalignment of up to 10 cm using a 1 kW wireless power transfer system.

Electromagnetic model-based foreign object detection (EM-FOD) is also presented. The detection metric is a sequent error in the Tx coil current reconstruction, which results from a foreign object’s electromagnetic coupling. Hardware demonstrations show that a U.S. nickel coin can be detected using only 9 W level, allowing less risky pre-startup low-power detection regardless of an Rx coil misalignment of up to 10 cm.

Chair: Professor Al-Thaddeus Avestruz