This thesis focuses on the topic of preventive maintenance for electric aircraft and aims to examine its significance and implementation within the aviation industry. Electric aircraft have become increasingly popular as a sustainable alternative to conventional aircraft, making it crucial to develop effective maintenance strategies to ensure their reliability and performance. To achieve this objective, a comprehensive literature review of existing research and practices in the field of preventive maintenance for electric aircraft is conducted. The study identifies the key components and systems in an electric aircraft that require regular monitoring and maintenance, such as electric motors, batteries, power converters, and control systems. By analyzing the benefits of preventive maintenance, such as reduced downtime, increased component lifespan, and decreased maintenance costs, various methods, and techniques for implementing preventive maintenance for electric aircraft are presented. This includes the use of condition monitoring systems, sensors, and data-driven analysis to monitor and predict the health of components and anticipate any faults or deviations in advance. To explore the challenges of preventive maintenance for electric aircraft, aspects such as data management, cooling, and electromagnetic compatibility are also discussed. Furthermore, the need for training and skill development for maintenance personnel to effectively carry out preventive maintenance activities for electric aircraft is explored. By compiling and analyzing the available information, this thesis provides a comprehensive overview of preventive maintenance for electric aircraft and its significance in ensuring reliability, performance, and sustainability within the aviation industry. The findings can be valuable to airlines, maintenance organizations, and researchers interested in implementing effective maintenance strategies for electric aircraft and contributing to the continued development of sustainable aviation. The literature review showed that the use of preventive maintenance strategy for electric aircraft is well-founded and supported by research and experiences from various industries. The implementation of IoT and fault diagnostic techniques can enhance the maintenance process and increase the reliability of electric aircraft by identifying and addressing potential faults at an early stage. These findings provide valuable insights and guidelines for the aviation industry in developing and optimizing their maintenance strategies for electric aircraft.

The introduction of inverters utilizing wide band-gap semiconductors allow for higher switching frequency and improved machine drive energy efficiency. However, inverter switching results in fast voltage surges which cause overvoltage at the stator terminals and uneven voltage distribution in the stator winding. Therefore, it is important to understand how next generation machine drives, with higher switching frequency, affect the voltage distribution. For this purpose, a lumped-parameter model capable of simulating winding interturn voltages for the wide frequency range of 0-10 MHz is developed for a slotless PMSM. The model includes both capacitive and inductive couplings, extracted from 2D finite element simulations, as well as analytically estimated resistive winding losses. The developed model of a single phase-winding is used to investigate how machine design aspects such as insulation materials and winding conductor distribution affects both voltage distribution and winding impedance spectrum. Validation measurements demonstrate that the model is accurate for the wide frequency range. The sensitivity analysis suggests that the winding conductor distribution affect both impedance spectrum and voltage distribution. For the slotless machine, capacitance between the winding and the stator is several times smaller than capacitance between turns. Therefore, the high-frequency effects are dominated by the capacitance between turns. Insulation materials that affect this coupling does therefore have an impact on the impedance spectrum but does not have any significant impact on the voltage distribution. / Nästa generations inverterare för styrning av elektriska maskiner, baserade på bredbandgaps komponenter, tillåter högre switchfrekvenser vilket skapar en energieffektivare drivlina. Nackdelen är att snabba spänningsflanker från den höga switchfrekvensen skapar överspänning på stators anslutningar och en ojämn spänningsfördelning i statorlindningen. Det är därför betydelsefullt att förstå hur dessa nya drivlinor påverkar lindningens spänningsfördelning. I denna rapport används en modell kapabel att simulera lindningens spänningsfördelning i det breda frekvensspektrumet 0-10 MHZ. Modellen är framtagen för en faslindning av en PMSM, utan statoröppning, som inkluderar både kapacitiva och induktiva kopplingar samt analytiskt beräknade lindningsförluster. Modellen används för att undersöka spänningsfördelningen i lindningen samt inverkan från designparametrar som isolationsmaterial och lindningsdistribution. Känslighetsanalysen visar att lindingsdistributionen har en signifikant påverkan på både impedansspektrumet och spänningsfördelningen. För den studerade maskintypen är det kapacitansen mellan varv som är dominerande för högfrekventa fenomen. Isolationsmaterial som påverkar denna koppling har en påverkan på impedansspektrumet men är liten för spänningsfördelningen.