Radiated Noise Dominancy Analysis by Extended Double Pulse Test and Power Device Optimization for Inverter Use

Abstract

Conventionally power device characteristics were measured by a double pulse test on half bridge circuit and radiated noise was estimated by analyzing results of switching speed. This conventional method is indirectly effective to consider common and differential mode noise in final products since noise is formed by a combination of impedance on route and higher harmonics by source of signal. However, directly measurable methods for radiated noise from power devices before being assembled into final products are expected to shorten power device development periods for the sake of establishing both of low radiated noise and low losses during conduction and switching. Hence, this paper proposes an extended double pulse test and describes that radiated noise can be also measured at the same time of measuring switching characteristics. Additionally, dominant timing can be separated, whether turn on or turn off with conduction current dependency, after analysis of directly detected radiated noise signal on a conventional half bridge. Using this method, both loss and radiation noise of the switching device can be measured simultaneously and further optimization on IGBT / CSTBT chip structures can be established in short period of time.