Modeling and Analysis of Multiphase Electric Machines for High Power Applications

Electric machines with more than three phases are gaining more and more importance especially in high-power applications. The vast majority of AC electric machine theory has been developed under the assumption of a three-phase design and is not intuitively extendable to the case of a larger phase count. Thereby, in many circumstances the need arises for new theoretical methods to be worked out if one needs to mathematically model multiphase motors and generators with the same degree of accuracy and reliability as normally done for three-phase machines. The proposed book provides a comprehensive treatment of multiphase electric machine theory as concerns their mathematical modelling and analysis. Existing modelling techniques are reviewed critically and new approaches are presented in their theoretical derivation and experimental validation. Special attention is devoted not only to the mathematical details of models, but also to their parameter calculation from design or measurement data. This is crucial for making models practically useful in the machine design stage as well as for machine performance prediction through numerical computer simulations. Whenever possible, multiphase machines are treated throughout the book in a unified and general manner, i.e. independently of how many phases they have and of how the phases are geometrically arranged. Especially when new methods are set forth, chapters are quite rich in mathematics; however, application examples, numerical implementations or experimental validations are always provided so that the reader can understand the purpose at which the theory being developed is aimed and may possibly use results only, skipping mathematical derivation details.

Reasons for the multiphase option in the design of high power electric machines.- Multiphase motors in high power industrial drives: the case of a 45 MW 12-phase motor for LNG industry.- Multiphase technology in electric power generation.- Stator multiphase design and winding construction technology in high power electric machines.- General equivalent circuit model of split-phase machines in Park's coordinates.- Closed-form expressions of dqO model parameters from physical machine inductances.- Model experimental evaluation on sample machines.- Model implementation in the Matlab-Simulink environment and experimental assessment.