# A Survey on Mission-Profile-Based Stress Testing of Electric Motor Drives
## 1 Introduction  
The problem of the reliability and lifetime expectancy of drive components plays an important role in the electrification of industrial facilities, where AC electric machines and power electronics are increasingly being used to reduce the dependence on fossil fuels [1]. There is an increasing number of power plants that utilize electricity generated from renewable energy sources. The automotive industry is also moving towards electrification of the propulsion system, which requires the development and optimization of the drivetrain itself [2]. What is common to all the mentioned areas of application is the use of an electric motor drive (EMD). A typical EMD structure is shown in Figure 1. The EMD is a complex system consisting of several components working together to achieve optimal and desired performance characteristics, with the electric motor and power converter as its main components [3, 4]. Other parts of the drive system include the control units, protection units, cables, insulation, sensors, and mechanical loads. All of these components have an impact on the drive's dynamics, efficiency, lifetime, reliability, and amount of cost in terms of consumed electricity. In practice, the impact on the drive's dynamics, lifetime, and reliability can be traced through mission-profile-based stress testing. A mission profile can be defined as a simplified representation of all relevant static and dynamic load conditions to which a drive component is exposed throughout its entire lifespan [5]. The drive's lifespan and reliability are mainly affected by the stress factors of which the mission profile is composed [6]. According to [7], the lifespan of the component is defined as the periodduring which the component can operate correctly within specified parameters before a failure occurs or its performance significantly degrades. On the other hand, the reliability is defined as the probability that a drive component can perform its intended function for a specified interval under stated conditions [8]. A significant amount of effort has been made on mission-profile-based stress testing of EMD components. However, the majority of the existing literature focuses on testing only one component of the EMD, without considering the stress induced on other parts of the system [9; 10; 11; 12]. Papers [9; 10] focus on testing power converters, while papers [11; 12] examine only electric motors. Some related reviews on mission-profile-based stress testing are listed in Table 1. In [13], the concepts of mission profile emulation for electric machine drive systems are presented. The systematization and development of drive cycles (speed mission profiles) for electrochemical propulsion are described in [14]. A detailed review of the existing methods for monitoring the insulation condition and detecting faults in low-voltage induction motor windings is provided in [15]. In [16], a review of strategies for managing the lifetime of power electronic converters is presented. All of these aforementioned papers overlooked the impact of stress on the other parts of the system. Comprehensive mission profiles are essential for effectively testing the EMD as they help evaluate its impact on the reliability and lifespan of the entire system. Moreover, the existing literature lacks well-defined testing procedures and a systematic categorization of stress factors needed to push the EMD to its operational limits. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Reference** & **Year** & **Target Component** & **Note** \\ \hline
[15] & 2008 & \
\begin{tabular}{c} Motor stator winding \\ (insulation) \\ \end{tabular} &
\begin{tabular}{c} Presented testing methods for \\ stator insulation of EMD \\ Power electronics based \\ emulation of electric machine \\ A lifetime analysis of power \\ electronic converters \\ A review of drive cycles \\ (speed profile) \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Related review papers on mission-profile-based stress testing. Figure 1: A typical EMD structure.