D4.1 Physical characteristics selected to monitor the performance of the powertrain  

Executive Summary

This document describes work carried out in the HEMIS project concerning the identification of the physical characteristics to be used for monitoring the performance of the motor and control systems of the Fully Electrical Vehicle (FEV).

The first issue addressed has been the identification of the motor and control components, and their failure modes which are deemed most critical and, thus, worth for consideration by the Prognostics and Health Monitoring System (PHMS). Indeed, since the motor and control systems are formed by several components that can undergo different degradation and failure modes, the most critical components and their failure modes have to be identified. The selection process has been primarily based on the criticality of the motor and control failure modes of the components measured by their Risk Priority Number (RPN). The impact of the failure modes on the maintenance costs has also been considered in the selection decision.

The analysis has led to the selection of the components and failure modes reported in Table A and B in the motor and control systems, respectively.

Table A. Most critical components and failure modes in the motor system.


Failure mode

Permanent Magnet field source

Loss of magnetic flux


Inner race failure

Outer race failure

Balls failure

Motor stator windings


Short Circuit

Open Circuit

 Table B. Most critical components and failure modes in the control system.


Failure mode


Short circuit

Open circuit

Loss of gate control

Increased leakage current

Gate Driver



Electrolyte Vaporization

Then, the physical characteristics which can be used to assess the component degradation state and failure time have been identified on the basis of the indications of the Failure Mode and Effect Analysis (FMEA), expert knowledge of the project partners and the findings of a literature review on existing PHMS for motor and control systems of vehicles. The analysis of the relevant factors related to the feasibility of use in practice of the identified physical characteristics has been performed, e.g. on the feasibility and cost of integration in the vehicle, the accuracy of measuring and the complexity of the associated data processing, in order to identify those which cannot be used by the HEMIS PHMS. The detectability, diagnosticability and prognosticability of component failures using the remaining physical characteristics have been assessed. These analyses have led to the final selection of the physical characteristics to be considered for monitoring the motor and control systems (Tables C and D).

The proposed lists of physical characteristics are not intended to be frozen: if during the project development, the selected physical characteristics were found not sufficient informative for the PHMS, other informative physical characteristics will be considered. Finally, electromagnetic noise will also be studied to understand its evolution during inverter components degradation and assess its possible use as alternative/additional physical characteristic for PHMs: the results of WP5 will be taken into account for that purpose.

Table C. Physical characteristics selected for monitoring the performance of the motor.





Magnetic Flux

Angular Speed

Table D. Physical characteristics selected for monitoring the performance of the control.

Stator Current


Equivalent Series Resistance (Capacitor)

Capacitor Surface Temperature

IGBT Case Temperature

Gate Voltage (IGBT)

Gate Current (IGBT)

Collector Current (IGBT)

Collector-Emitter ON voltage (IGBT)

Project acronym:

Project name:
 Electrical powertrain Health Monitoring for Increased Safety of FEVs

Project reference:

Start date: 01/06/2012
End date: 28/02/2015

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