School of
Information Technology and Electrical Engineering

Speaker: Amir Ganjavi
Seminar Date: Fri, 15/11/2019 - 14:30
Venue: 01-E356; Forgan Smith building
Host: Prof Firuz Zare

Seminar Type:  PhD Confirmation Seminar

Abstract: 

In this project, new filters will be designed and/or the existing filters will be modified to comply with the new frequency range of 2–150 kHz in adjustable speed drives (ASDs). The design of the filters should be in a way that they do not affect the previously designed filters related to the frequency ranges of 0–2 kHz and 0.15–30 MHz. This project is composed of two main sections: System level and component level.

At the system level, we need to construct the comprehensive model of the drive system to predict the parasitic behaviour of the system at different frequency ranges. To do this, the noise sources should be analysed. These noise sources are generated based on an interaction between converters, cables, and the load. Topology of converters, such as Active Front End (AFE), inverter, and diode rectifier affects voltage and current harmonics and EMI sources. Moreover, the type of PWM technique, switching frequency, and voltage slope rates (dv/dt) affect the voltage and current harmonics and EMI sources. These will be comprehensively analysed in this project. On the other hands, cables significantly affect the system model and consequently resonances, depending on their type and length. In this project, in order to deal with the model of the cables, they will be analysed in Finite Element Software (ANSYS Q3D). So far, an asymmetrical model AC motor as the load has been proposed. This model effectively deals with the frequency dependency of materials namely, permeability, permittivity, and skin depth.

At the component level, a) to reduce the undesired capacitive couplings at higher frequency ranges, b) minimize the frequency dependency of inductor and c) increasing losses at high frequencies, new inductors with novel core materials and configurations will be developed for the filters. The idea of the new configuration of inductors is filling the winding gaps with layers of powders to reduce the capacitive couplings and changing them to lossy elements to damp the resonances at different frequencies; in fact, it is aimed that the filters have their maximum losses around the resonance frequencies. Moreover, the existing harmonic filters (at the AC or DC side) are made up of magnetics that significantly drop from above 1 kHz. Accordingly, the proposed solution to make the harmonic filters cover the frequency range of 2–150 kHz is to use hybrid core materials. After proposing the novel configurations and core materials, they will be experimentally characterized and then used in the system platform explained above.

After characterizing the proposed materials and configurations of the inductors and modelling the whole system, filters will be designed for the frequency range of 2–150 kHz. The parameters of the proposed filters are optimized through optimization software, assigning a trade-off between efficiency, size, reactive power and effectiveness of the filter. Finally, the proposed filters for the frequency range of 2–150 kHz will be validated through an experimental setup.

Biography: 

Amir Ganjavi received the B.Sc. and M.Sc. degrees in electrical engineering from the Babol Noshirvani University of Technology, Babol, Iran, in 2014 and 2017, respectively. He is currently working toward the Ph.D. degree in electrical engineering at the University of Queensland, Brisbane, Australia.His research interests include dynamic stability and control of power electronic systems, power converters and their applications in renewable energy, and electromagnetic interference (EMI).