Design and analysis of advanced nonoverlapping winding induction machines for EV/HEV applications

This paper presents a detailed analysis and design guidelines for advanced nonoverlapping winding induction machines (AIMs) with coil-pitch of two slot-pitches by considering some vital empirical rules and flux-weakening characteristics. The aim of the study is to develop a type of new winding and stator topology for induction machines (IMs) that will lead to a decrease in total axial length without sacrificing torque, power, and efficiency. The key performance characteristics of the improved AIMs are investigated by 2D time-stepping finite element analysis (FEA) and compared with those of IMs having fractional and conventional overlapping and nonoverlapping windings. Compared with the conventional overlapping winding counterpart of the AIM, a ~25% shorter axial length without sacrificing torque, output power, and efficiency is achieved. In addition, the influences of major design parameters, such as stator slot, rotor slot and pole numbers, stack length, number of turns per phase, machine geometric parameters, etc., on the flux-weakening characteristics are investigated. It has been concluded that the major design parameters have a considerable effect on the electromagnetic performance. However, among those parameters, the influences of pole number and stack length together with the number of turns on flux-weakening characteristics are significant

Analysis and Reduction of On-Load DC Winding Induced Voltage in Wound Field Switched Flux Machines

DC winding induced voltage pulsation in wound field switched flux (WFSF) machines causes dc winding current ripple and field excitation fluctuation, challenges the dc power source, and deteriorates the control performance. Hence, reducing this pulsation is important in the design of a WFSF machine. In this paper, based on the analytical models, rotor skewing and rotor iron piece pairing are proposed and comparatively investigated by the finite-element (FE) method to reduce the on-load dc winding induced voltage in WFSF machines having partitioned stators and concentrated ac windings. FE results show that peak-to-peak value of the on-load dc winding induced voltage in the analyzed 12/10-pole partitioned stator WFSF (PS-WFSF) machines can be reduced by 78.42% or 77.16% by using rotor skewing or rotor pairing, respectively, while the torque density can be maintained by &gt;90%. As for the 12/11-, 12/13-, and 12/14-pole PS-WFSF machines, by using rotor iron piece inner arc pairing, the on-load dc winding induced voltage can be reduced by 64.11%, 52.12%, and 76.49%, respectively, while the torque density can be maintained by more than 90%. Prototypes are built and tested to verify the analytical and FE results.</p

3D Numerical Modelling of Claw-pole Alternators with its Electrical Environment

International audienceThis paper describes a methodology for modelling a six-phase claw-pole alternator with its electrical environment. Magnetic nonlinearities, eddy currents and rectifiers are taken into account. To solve magnetodynamic problems, we use the modified magnetic vector potential formulation. The complex structure of the machine requires a 3D finite element analysis. To limit the mesh size, we introduced a refinement strategy based on the calculation of the time derivative of magnetic vector potential, solution of the magnetostatic case. In addition, we propose to reduce the transient state by improving the initial solution from the solution of a magnetostatic problem. These different numerical techniques reduce drastically the computational time and memory resources. To validate the proposed approach, some results are compared with experimental ones