DIGITAL & ROBOTICS LAB
ENGINEERING EXTENSION
WIRELESS ENERGY TRANSFER
Electric Vehicles (EV) have gained in popularity due to environmental concerns, increases in price of fossil fuels, and a subsequent desire to move toward renewable energy sources, despite issues associated with EV usage including infrastructure maintenance, vulnerabilities to inclement weather and vandalism, as well as overlooking making charger connections. Wireless Charging (WC), which operates on magnetic resonance for Wireless Power Transfer (WPT), allows these problems to be alleviated
The efficiency of wireless power transfer is sensitive to the horizontal and vertical distances between the transmitter and receiver coils due to the magnetic coupling change. To address the output voltage variation and efficiency drop caused by misalignment, a uniform voltage gain frequency control is implemented to improve the power delivery and efficiency of wireless power transfer under misalignment. The frequency is tuned according to the amplitude and phase-frequency characteristics of coupling variations in order to maintain a uniform output voltage in the receiver coil. Experimental comparison of three control methods, including fixed frequency control, resonant frequency control, and the proposed uniform gain control was conducted and demonstrated that the uniform voltage gain control is the most robust method for managing misalignment in wireless charging applications
A magnetic sensing system for alignment in wireless EV chargers. The system utilizes the existing charging facility to generate a magnetic field and sense the relative distance between the two coil centers. The system also requires four minor coils to be installed on the secondary pad for direction detection using triangulation. The four small coils are also able to adjust the alignment when the two major coils are close enough, ensuring the primary and secondary pads are well aligned