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HomeEvents and SeminarsPhD Dissertation DefensesDoctoral Defense: Yalda Azadeh

Doctoral Defense

Wide Band Gap Power Converter and Its High Frequency Side Impacts on Motor Drive System

Yalda Azadeh

December 06, 2024
1:30 - 3:30 PM
Light Engineering, Room 250
Advisor: Dr. Fang Luo

Understanding voltage stress across motor winding is critical for insulation health when its series resonance frequencies which have least impedances, known as antiresonances, coincides with OV resonance frequencies across it, named as Antiresonance Phenomenon (ARP). First, this work discloses that the OV resonance frequencies across motor winding (load) can be represented by the combination impedance of cable plus load. Second, it investigates the interactions between the cable and load impedances in different layouts and examines their impact on the ARP. Then, it discloses the sensitivity of voltage stress across joints versus cable and load impedance parameters. From the voltage stress correlation with these parameters, establishes a safe operation area as motor drive system design guideline. We noticed that the overvoltage across different junctions of the cable/motor winding will be highly dependent on the accurate understanding of impedance of higher order frequencies across that junction and dV/dt propagated from source to that junction. This work is trying to understand how to include this new influence and have simplified model more inclusive of higher order harmonics and dV/dt. This shows that we can not only look at the terminal of the input of the motor winding, but also need to consider the voltage distribution across the winding. Lastly, this work investigates the influences of cable length on electromagnetic interface (EMI) in a WBG-based drive system. This work offers a simplified methodology to optimize the reliability of the drive system. By using this approach, the work suggests dV/dt control of PWM excitation signal, drive system layout/configuration and incorporate new variables (caused by WBG power electronics-based power conversion and high-speed motor drives) into the existing reliability standard framework.