Magnetic Alignment Detection Using Existing Charging Facility in Wireless EV Chargers

Abstract

Wireless charging is a promising outlet to promote the electric vehicle (EV) industry due to its safe and noncontact manner. Wireless EV chargers require the secondary receiver coil to be well aligned with the primary station for efficient charging, which could require more of the driver’s time and attention when parking a vehicle. Therefore, this paper presents a magnetic alignment system to assist the EV driver during parking. The magnetic alignment approach uses the existing coil and frequency tracking control electronics of wireless chargers to detect the distance between the two coils while using 4 small auxiliary coils for direction and fine adjustment, leading to a cost effective detection method for coil alignment in electric vehicle wireless charging (EVWC). The testing results of a prototype show acceptable measurement correctness and the mean error for ten trials in range detection is within 0.25 cm at three different misalignment conditions (10.5, 15, and 20 cm). The positioning accuracy of coil alignment is within 1.2 cm for three different start positions with the auxiliary coils.

Receiver–Coil Location Detection in a Dynamic Wireless Power Transfer System for Electric Vehicle Charging

“…EV detection, combined with position or misalignment measurement, can be achieved by various techniques [ 12 ]: completely separate sensors, based on other techniques such as optical (video camera) [ 13 ], tag readers (RFID technology) [ 14 ], GPS [ 15 ], etc. ; additional inductive sensors embedded with the IPT coils, such as interposed detection coils [ 16 , 17 ], Hall sensor array [ 12 ], ferrite antenna [ 18 ] or TMR (tunneling magnetoresistive) sensors foil [ 19 ]; special design of transmitter and receiver coils, such as overlapping D- and Q-coils, as described in [ 20 ]; exploiting existing IPT coils of a resonating array, determining the behavior of the circuit as a function of position. …”

“…additional inductive sensors embedded with the IPT coils, such as interposed detection coils [ 16 , 17 ], Hall sensor array [ 12 ], ferrite antenna [ 18 ] or TMR (tunneling magnetoresistive) sensors foil [ 19 ];…”

Accurate Offset Angle Detection Strategy for Wireless Charging Coils Based on Electronic Compasses

“…One is the lateral and longitudinal offset, and the other is the angle offset. The technique of setting a detection coil around the transceiver coil and determining its position by detecting the phase angle characteristics and resonant frequency of the coil is proposed in [15] for wireless charging coil positioning technology. A number of additional auxiliary coils are added in [16]- [18] to allow translation positioning to be achieved by detecting the induced voltage between them and the charging coil.…”