UBC Theses and Dissertations
Efficient modelling of special purpose multi-phase electrical machines for transient simulation programs Amiri, Navid
Design and analysis of power systems has always been reliant on mathematical models of power system components and their implementation in sophisticated electromagnetic transient (EMT) simulation programs. Electric machines are the dominantly used components in models of power grids, and in most simulation programs rotating machines are represented using lumped-parameter models based on magnetically-coupled phase windings. Advancements in semi-conductor devices have allowed conventional three-phase machines as well as multi-phase machines (with more than three electrical phases) to be used with power electronic interfaces in wide range of electromechanical energy conversion applications, including advanced motor drive systems as well as integration of renewable energy. The multi-phase machines, at the expense of their increased complexity, may also provide additional advantages over the conventional three-phase machines, e.g. reduced power per phase, reduced semi-conductor current/voltage rating per phase, increased reliability, fault tolerant operation, etc. However, such multi-phase machines have unique electromagnetic characteristics and complex mathematical models which also become additional challenge in terms of both implementation and numerical performance in simulation programs. The main goal of this dissertation is to propose accurate and numerically efficient models of multi-phase machines which also consider key characteristics such as magnetic saturation and flux harmonics. In this dissertation, the voltage-behind-reactance (VBR) methodology has been used to derive new models for wound-rotor six-phase synchronous machines (including leakage flux cross-coupling and magnetic saturation), five-phase machines (including flux harmonics and inter-harmonic couplings) and also three-phase saturable induction machines considering flux harmonic distortions. The new models possess the advantage of constant-parameter interfacing circuits when implemented in state-variable-based (SVB) simulation programs, which has not been possible prior to this work. Numerous case studies demonstrate the advantageous numerical accuracy and efficiency of the proposed models, and their beneficial impact on simulation performance compared to the alternative existing state-of-the-art machine models of the same class. It is envisioned that due to their numerous advantages the new models will become included in many commonly-used commercial EMT programs, and will benefit thousands of researchers and engineers worldwide.
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Attribution-NonCommercial-NoDerivatives 4.0 International