Loss Model and Efficiency Analysis of Tram Auxiliary Converter Based on a SiC Device

Hao Liu,Fei Lin,Zhongping Yang,Xianjin Huang

doi:10.3390/en10122018

Abstract

Currently, the auxiliary converter in the auxiliary power supply system of a modern tram adopts Si IGBT as its switching device and with the 1700 V/225 A SiC MOSFET module commercially available from Cree, an auxiliary converter using all SiC devices is now possible. A SiC auxiliary converter prototype is developed during this study. The author(s) derive the loss calculation formula of the SiC auxiliary converter according to the system topology and principle and each part loss in this system can be calculated based on the device datasheet. Then, the static and dynamic characteristics of the SiC MOSFET module used in the system are tested, which aids in fully understanding the performance of the SiC devices and provides data support for the establishment of the PLECS loss simulation model. Additionally, according to the actual circuit parameters, the PLECS loss simulation model is set up. This simulation model can simulate the actual operating conditions of the auxiliary converter system and calculate the loss of each switching device. Finally, the loss of the SiC auxiliary converter prototype is measured and through comparison it is found that the loss calculation theory and PLECS loss simulation model is valuable. Furthermore, the thermal images of the system can prove the conclusion about loss distribution to some extent. Moreover, these two methods have the advantages of less variables and fast calculation for high power applications. The loss models may aid in optimizing the switching frequency and improving the efficiency of the system.

Highlights

The power supply system in trams includes two parts, the traction power supply system and the auxiliary power supply system
The auxiliary power supply system is tasked with all the auxiliary devices including air conditioners, compressors, fans, etcetera but not the main circuit of the traction system
The reliability of the auxiliary converter plays an important role in the smooth operation of the vehicle

Summary

Introduction

The power supply system in trams includes two parts, the traction power supply system and the auxiliary power supply system. The auxiliary power supply system is tasked with all the auxiliary devices including air conditioners, compressors, fans, etcetera but not the main circuit of the traction system. An important component of the auxiliary power supply system is the auxiliary converter, the capacity of which is typically tens of kilovolts, the bus voltage is 750 V and the outputs are AC 380 V and AC 220 V. The reliability of the auxiliary converter plays an important role in the smooth operation of the vehicle. Since the auxiliary converter is a necessary part of vehicle equipment, its weight and volume have been a focus of great attention [1,2,3,4,5,6]

Objectives

Results

Conclusion