High Power/Current Inductor Loss Measurement with Shunt Resistor Current-sensing Method

With the high-power-density converters requirement increasing, the power loss analysis of inductive components requested further accurate. Some of the inductors are operated at high frequency and current conditions. However, the high precisely measurement instruments, B-H analyzer, only can provide maximum +/- 6A AC ripple current condition at present. In this paper, a low-cost measurement method by using the shunt resistor as a high current sensor is proposed. To abbreviate the measurement deviation cause by the parasitic inductance of shunt resistor, the Runge-Kutta calculation method is applied to figure out the inductor current. Furthermore, a shunt resistor connecting configuration is proposed to reduce the parasitic inductance influence. To demonstrate the feasibility, an inductor is measured under 160 A (RMS) current, 10 kHz switching frequency, and 50 % duty cycle square-wave-voltage measurement conditions as an example.