High power/current inductor loss measurement with improved shunt resistor construction

Abstract

The increasing requirement for high-power-density converters has resulted in the need for accurate analysis of the power loss of inductive components. Some inductors are operated at high frequency and current. However, the maximum AC ripple current measurement range of B-H analyzer, which is a high precision measurement device, is ±6 A. In this paper, a low-cost measurement method using the shunt resistor as a high current sensor is proposed. To abbreviate the measurement deviation caused by the parasitic inductance of shunt resistor, the Runge-Kutta calculation method is applied to determine the inductor current. Furthermore, a shunt resistor connection configuration is proposed to reduce the influence of parasitic inductance. To demonstrate the feasibility of this method, an inductor is measured under 160 A (RMS) current, 10 kHz switching frequency, and 50% duty cycle square-wave-voltage as an example.