Analysis of Dead Time Influence on Common Mode Volt-Second and Inductor Saturation in Three-Phase DC-Fed Motor Drive Systems

摘要

This paper presents a systematical analysis to predictrnthe volt-second on the inductors of EMI filters throughrnanalytical calculation and provides a detailed analysis about thernimpact of system dead time on inductor saturation for EMI filterrndesign. The equivalent circuit for inductor volt-secondrnprediction is presented. Based on the equivalent circuit, arnprediction method is proposed to analytically calculate the voltsecondrnon the common mode (CM) inductors using doublernFourier integral transformation (DFIT) method for noise sourcerncalculation. Moreover, the impact of dead time on the outputrnvoltage spectrum and inductor volt-second is discussed in detail.rnThe results show that the volt-second on the inductors can bernpredicted through analytical calculation and the impact of deadrntime on inductor saturation is related with system modulationrnmethods, dead time value and also the inductors’ andrncapacitors’ value selection of the EMI filters. The analysis isrnbased on a dc-fed motor drive system with output EMI filter asrnan example and the verifications are carried out through bothrnsimulations and experiments on a 3 kW motor drive system.