Measurements of Minor Loop Position and Shape Depending on Inductor Excitation Process

Abstract

Inductors used in power converter circuits are subjected to various currents when rectangular voltage waveforms are applied. Under these conditions, instead of forming a hysteresis loop, the magnetic material in the inductor forms minor loops on the BH plane corresponding to the current flow. The area of these minor loops represents the iron loss per unit volume. The shape and area of the minor loops vary depending on the values of the rectangular voltage waveform and DC current, as well as the position of the loop on the BH plane. This paper proposes a measurement procedure to accurately measure and analyze the position and shape of minor loops by controlling the current flowing through the inductor in a half-bridge inverter.