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This paper proposes a novel hybrid excitation permanent magnet (PM) machine with an independent ac excitation port to extend the speed range and improve the torque capability. The proposed machine is characterized by an axial stator placed in one side of the rotor, which provides a shunted flux path of the radial stator. The prominent merit of the proposed machine is that it can make better utilization of the PM flux and offer a large flux regulation capability because the radial flux and the axial flux are in parallel to each other. Thorough analysis of the field distribution is performed by three-dimensional (3-D) finite-element analysis, and different operation modes of the proposed machine are illustrated and compared. Then, the flux regulation capability of the machine is analyzed using the simplified magnetic equivalent circuit, which is proved to give reasonable precision, indicating that the flux regulation ratio only depends on the design parameters of the ac excitation port. Finally, a 36-slot/six-pole prototype using the proposed configuration is built and tested. It is verified that the proposed machine exhibits excellent performance of flux regulation, thus offering a good potential to be used in wide-speed-range driving applications. [ABSTRACT FROM AUTHOR]

Linear switched reluctance motors (LSRMs) provide an alternative to linear induction motor and linear permanent magnet motor in both vertical and horizontal propulsion applications. This paper attempts to develop a unitized design method of a segmental secondary LSRM, which is characterized by a modular magnetic circuit structure and the independent operation of multimover units. The developed design method is directly performed in linear domain without transforming it to a rotary SRM, which complies with the essential natures of the segmental secondary LSRM, showing that it is capable of delivering more power at the same dimensions compared to the conventional tooth type LSRM. Further, the sensitivity analysis of the critical geometric parameters is performed, and the guidelines for selection of the best dimension parameters are given. Finally, the three-phase and four-phase LSRMs are designed and prototyped, respectively with a 1-m long stator. The experimental results validate the design procedures and analysis above. [ABSTRACT FROM AUTHOR]

Thermal analysis is an important issue in machine design which allows to have a knowledge of the machine temperature rise. This paper presents the thermal analysis, modeling, and experiments of a linear-switched reluctance machine (LSRM) with toroidally wound mover and segmental structure. First, a 3-D heat flow model with the homogenized region for the presented LSRM is established using the thermal equivalent circuit. The equivalent thermal resistance of the model is developed together with the nodes forming of the thermal resistance network. The thermal identification to each component such as windings and core steel is performed. Then both the numerical 2-D and 3-D heat flow model for the presented LSRM are established by finite-element analysis which can give the detailed temperature distribution of the entire machine. At last, the actual experiment on a prototype is carried out, validating the accuracy, and feasibility of the thermal equivalent model above. [ABSTRACT FROM AUTHOR]

Linear switched-reluctance motor (LSRM) is investigated and proved to be an alternative for direct linear driving systems, especially for long-distance transportation applications, such as vertical elevator driving motor. This paper presents the design, sensitivity analysis, and optimization of a toroidally wound mover LSRM with segmental stator. The presented LSRM has much higher copper utilization ratio and flux carrying capability than the conventional LSRM for vertical linear propulsion application. The features of motor performance influenced by various geometrical parameters are described using magnetic circuit and finite element analysis to give the guidelines for selecting the reasonable range of those parameters of this kind of machine. Furthermore, an optimization procedure is performed to obtain the optimal machine dimensions considering active payload ratio and force ripples. Finally, the experimental results from the prototype validate the design procedures and analysis above. [ABSTRACT FROM PUBLISHER]