Magnetic field measurement near wireless power transfer systems

Measurement method of magnetic field near a magnetic source is investigated. Frequencies of the magnetic field are 100 kHz and 6.78 MHz. As a result, even if magnetic sensor is placed nearest to the source, change of current flowing through the source is marginal in this study. When the sensor whose measuring area is 100 cm² is moved closer to the source, the difference between the actual strength of the magnetic field and that estimated using the sensor increases. At the source-sensor distance of 20 cm, the estimated strengths are 0.9 and 2.2% higher than the actual field strength. On the other hand, the estimated strengths are 10.0 and 10.2% higher at the frequencies of 100 kHz and 6.78 MHz, respectively, at the distance of 0 cm.