Design and flux-weakening control of an interior permanent magnet synchronous motor for electric vehicles

Permanent magnet synchronous motors (PMSMs) provide a competitive technology for EV traction drives owing to their high power density and high efficiency. In this paper, three types of interior PMSMs with different PM arrangements are modeled by the finite element method (FEM). For a given amount of permanent magnet materials, the V shape interior PMSM is found better than the U-shape and the conventional rotor topologies for EV traction drives. Then the V shape interior PMSM is further analyzed with the effects of stator slot opening and the permanent magnet pole chamfering on cogging torque and output torque performance. A vector-controlled flux-weakening method is developed and simulated in matlab to expand the motor speed range for EV drive system. The results show good dynamic and steady-state performance with a capability of expanding speed up to 4 times of the rated. A prototype of the V shape interior PMSM is also manufactured and tested to validate the numerical models built by the finite element method.

Recreational Foodservice management: A Delphi study of needed competencies

The purpose of this study was to identify the needed competencies of a Recreational Foodservice manager. A three round Delphi method of iteration was used. Delphi is a research method that utilizes iterating rounds to elicit the opinion of a panel of experts regarding a specific subject.^ A nominating committee of 22 industry leaders was consulted to establish a panel of 40 management experts, of which 35 (87.5%) completed all three rounds of the Delphi study.^ Round One of the study identified 17 specific job functions of a Recreational Foodservice manager. The researcher prepared an instrument detailing 60 competencies derived from an analysis of Round One results and distributed it as a Round Two instrument requesting the panel opinion regarding the relative importance of each listed competency on a five point Likert scale.^ The results of Round Two were tabulated and analyzed to ascertain areas of consensus. A Round Three instrument was prepared advising panelists of all areas of consensus, their dissenting opinions, if any, and a request for a revised opinion.^ A final report was prepared listing the 60 competencies and the panel opinion that eight were of highest priority, 29 of above average priority, and 23 of average priority. No item received two other available ratings, below average priority and lowest priority.^ The implications of these findings suggest necessary areas of curriculum development and industry management development to implement professionalism for Recreational Foodservice managers. ^