Edge position detection of on-line vehicles with segmental wireless power supply

On-line vehicles with segmental wireless power supply obtain energy from power tracks without physical contact while traveling. When a vehicle moves from one segmental track to another, the power supply coil should be switched accordingly. As the secondary coil fixed in the vehicle moves along the primary coil mounted in the segmental track, the mutual inductance of these two coils changes, which results in the varying of the phase angle that the current lags the voltage in the resonant circuit at the primary side. The paper proposes a method to decide the switching time through detecting the changing of the phase angle.