Measurement accuracy verification for real-time power and impedance sensor for wireless power transfer systems

We, DAIHEN Corporation, have developed a real-time power and impedance sensor that enables real-time measurement of transmitted power and coil impedance in a kW class wireless power transfer during practical power transfer. Normally, accurate power measurement is assured only for characteristic impedance in which the reflected power is zero. However, the sensor we developed enables highly accurate measurement of power and load impedance at low impedance in practical applications besides characteristic impedance. This paper describes the calibration reference device and calibration method for highly accurate measurement, and measurement accuracy verification results.