Fault Detection and Localization for Limp Home Functionality of Three-Level NPC Inverters With Connected Neutral Point for Electric Vehicles
Journal article, 2019

This paper deals with the detection of single battery or inverter switch faults during operation of a common and an active three-level neutral-point-clamped (NPC) inverter with a connected neutral point. Here, the main focus lies on the detection and localization of open-circuit faults of the inverter's switches. Therefore, a fault detection algorithm, using a current estimator, and two fault localization algorithms, a pulse pattern injection principle and an online adaption of the space vector modulation (SVM), are investigated and verified through simulations and experiments. Also, investigated is how the powertrain can be operated under a fault condition, so that the vehicle can drive with a limited maximum power using an adapted SVM, referred to as "limp home" mode, to the next service station. It is shown, that an active NPC inverter can cope with any single short or open-circuit fault of the inverter's switches without bringing the vehicle to standstill, whereas a generic NPC inverter loses controllability if an open-circuit fault at an inner switch occurs. Furthermore, both inverter types are able to be operated just with half of the dc-link voltage in case of a failure in one part of the battery.

neutral point clamped (NPC)

fault tolerance



multilevel systems

Fault location


Anton Kersten

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Karl Oberdieck

RWTH Aachen University

Andreas Bubert

RWTH Aachen University

Markus Neubert

RWTH Aachen University

Emma Grunditz

Chalmers, Electrical Engineering, Electric Power Engineering

Torbjörn Thiringer

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Rik W. De Doncker

RWTH Aachen University

IEEE Transactions on Transportation Electrification

2332-7782 (eISSN)

Vol. 5 2 416-432

Subject Categories

Vehicle Engineering

Electrical Engineering, Electronic Engineering, Information Engineering

Control Engineering



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