Integrated Design for Reliability of Motor Drives in High-Power High-Speed Machines

Funding: This project has received funding from the European Union's Horizon Europe research and innovation program under the Marie Sklodowska-Curie Doctoral Networks grant agreement No 101072580 (HIPO).

Abstract:
In the past twenty years, there has been a transition from conventional electrical motor (EM) and electrical drive (ED), which were physically separated, to more compact and power-dense motor-drive combinations known as Integrated Motor Drives (IMDs). IMDs combine an EM and its ED into one mechanical unit. The integrated design method seeks new possibilities to create more reliable and flexible systems, especially for mobile applications where volume and mass are limiting factors. There are many advantages of IMDs compared to conventional motor and drive systems such as:
•increased power density,
•lower losses,
•lower costs,
•elimination of power transmission cables,
•higher reliability.
These are the reasons that researchers have dedicated their time to studying more on IMDs. There are different types of IMD in terms of where the ED is mounted on the motor. All configurations help to eliminate the cable which yields increased power density and efficiency. Designing a high-power high voltage IMD has many challenges especially the thermal effect on the ED components and reliable operation in wide speed range for a long time. Also, the effect from the ED to the EM can be excessive heat caused by high switching frequency, leading to degradation of bearing and insulation. Hence, in the case of an IMD, a high-reliability design is of paramount importance because there are mutual stresses impact between the EM and ED. The ED has components such as a power module, DC link capacitors, and microcontroller unit (MCU) whose performance and lifespan depend on the thermal and stress. Regarding the reliable design of the ED in IMDs, each sensitive part of power converter design that is prone to failure and degradation should be investigated carefully such as:
•the location of the converter in terms of heat and stress effect on power converter from motor and higher electromagnetic compatibility (EMC),
•inverter topology, switching frequency, control scheme, and PWM type to have a higher reliability,
•durability analysis of sensitive components such as DC link capacitor and power switches,
•cooling technique,
•hardware and software protection and post-fault operation capability.
Regarding the high-speed operation of the IMD, this point should be noted that the EM can operate in three regions: i) constat torque (below rated speed), ii) field weakening (between rated speed and critical speed), iii) deep field weakening (above critical speed). Operating at high speeds leads to a higher vibration and decreased temperature housing. So, the prone components in the ED may suffer from vibration of the motor at high speeds operation.
The main objective of this PhD project is to develop an innovative and systematic approach for an integrated design of reliable motor drives in high-power high-speed machines.
The expected outcomes from this project are:
•Propose a systematic approach to have a reliable design of the ED in an IMD,
•Define a thermal model of IMDs to ensure effective heat management and thermal performance optimization,
•Work on a novel control scheme with high reliability to drive the motor in wide speed range for integrated motor drive applications,
•Propose a new cooling technique for effective heat dissipation and power management,
•Set of validated test results to demonstrate a reliable operation including high-speeds and different load conditions.