However, it would be possible to have smaller temperature swings but then the test would take too long time. Theory This chapter will give the necessary introduction to insulated gate bipolar transistor (IGBT) modules.An IGBT is a semiconductor which can be explained as a combination of bipolar junction transistor (BJT), metal-oxide-semiconductor field effect transistor (MOSFET) and gate turn off thyristor (GTO).Reliability analysis of power electronics for heavy hybrid vehicle applications Master Thesis, Electric Power Engineering Martin Strängberg Department of Electric Power Engineering CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2014 Reliability analysis of power electronics for heavy hybrid vehicle application MARTIN STRÄNGBERG Department of Energy and Environment Division of Electric Power Engineering CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2014 Reliability analysis of power electronics for heavy hybrid vehicle applications MARTIN STRÄNGBERG MARTIN STRÄNGBERG, Department of Energy and Environment Division of Electric Power Engineering Chalmers University of Technology SE Göteborg Sweden Telephone 46 (0) Cover: Inside of a power electronic module Chalmers Bibliotek, Reproservice Göteborg, Sweden 2014 Reliability analysis of power electronics for heavy hybrid vehicle application MARTIN STRÄNGBERG Department of Energy and Environment Division of Electric Power Engineering Chalmers University of Technology Abstract The purpose of the thesis report is analyze the reliability of power electronics for heavy hybrid vehicles.
Since fossil fuels produce greenhouse gases, many companies within the transportation industry focus on introducing electric motors in their vehicles, either as hybrid or as fully electric vehicles.
Electric motors are in general more efficient than combustion engines and the electricity could be produced from sources with very low CO 2 -pollution.
Wöhler curves based on the test result for the diodes and the IGBTs are given.
The expected lifetime can be approximated depending on the condition.
Samer Shisha, and my supervisor in Chalmers, professor Torbjörn Thiringer, for their support and guidance during the project.
Furthermore I would like to thank the employees at Scania who have given me advices and ideas during the work.Since it seems that the failure were caused by the bond wires, longer time periods are needed if the test should be done to find when the modules fails because of solder delamination.Also passive cycling should be investigated together with other types of tests such as vibration and chemical tests to investigate if the modules are suitable for operation in a heavy hybrid vehicle.Since batteries are direct current (DC) sources and electric motors are often of altering current (AC) type, then some conversion of the voltage is needed.When the vehicle brakes, the power can be regenerated and charge the battery, the power electronics convert the energy from AC to DC.For this power level, IGBTs are most suited and therefore these will be the only type of 1 semiconductor for DC-AC conversion that is investigated.Since AC-DC conversion is common for electric vehicles diodes will also be investigated.This thesis focuses on the power electronic modules including IGBT and diode chips.Power electronics are used in the inverter between the battery and the motor in a hybrid electric or pure electric vehicle.The tests are done with an on time of 2 seconds, with this time cycle the bond wires are the part most likely to be the cause of failure.The lifetime of the modules varied between and cycles depending on the temperature swing, ΔT, and if it is a diode or an IGBT.