This paper deals with the design of a 200kW/ 370Nm, induction machine for electrical vehicles traction system. The design aims to enhance the performance of the current induction machine technology for mass production making it suitable to be a rare earth free solution for electric vehicle applications. To this extent, suitable materials have been analyzed and selected, also by using of mechanical analysis and experimental data. Rotor die-casting, hairpin stator winding and specific cooling systems have been adopted within the proposed solutions. Extensive analytical and numerical methods are used for performance evaluation all over the full speed range of the machine.

The paper presents the Line Start Synchronous Reluctance Motor (LSSynRM) technology as a promising avenue to bring IE3 motor portfolios to the IE4 efficiency class at contained manufacturing costs. Indeed, the achieving of IE4 efficiency class is concerning many motor manufacturers, where the small-medium manufacturers seem to face the higher efforts in converting their product portfolio. To this extent, a methodology to improve the IE3 Induction Motor (IM) efficiency by introducing the Line Start Synchronous Reluctance motor technology in the IM motor is presented. The new motor design guidelines and constraints are figured out to reduce the impact on the manufacturing process. The paper presents a detailed experimental validation of the realized prototype in steady-state and transient operation referring to a target IE3 IM. The prototype proved to be a cost-effective, mass production-ready solution for super-premium efficiency IE4 motors. The LSSynRM technology demonstrated to be an effective high-efficiency avenue at reduced manufacturing costs in a broad panorama of low-inertia industrial applications.

This paper investigates the impact of the wire selection on the performance of induction motors for automotive applications. The section of wire and the material are evaluated at a high speed of 200 kW in an induction motor designed for premium vehicle applications. The proposed solutions have the same electromagnetic and thermal constraints, as well as the same final encumbrance. The various wire and winding types differ in terms of slot design, phase resistance, end-winding overhanging portion, skin and proximity effects, and equivalent slot thermal conductivity. Their impacts are analyzed in terms of the operating area motor efficiency and they are tested in an automotive drive cycle, highlighting the advantages and disadvantages of each configuration.

The cage losses in induction machines due to spatial or time harmonics in the air-gap field are a crucial parameter for a precise estimation of the machine efficiency. Using finite element, the common approach to consider the overall cage losses, by performing complete time-domain analyses. Alternatively, a rough estimation is achieved introducing equivalent parameters in the circuital model. In this paper, a methodology for cage losses computation due to air-gap spatial field harmonics is described. The proposed finite element procedure is faster than the time-domain analysis, since it is based on magneto-static and linear time-harmonic simulations to carefully consider the iron saturation and compute the induced currents in a specific working point. In the paper, a detailed procedure description and comparison with respect the time-domain approach is reported.

This paper compare different control strategies of the synchronous reluctance motor to outline their impact on the accuracy of flux-observer based sensorless operation. Maximum torque per ampere, maximum efficiency, and maximum power factor controls, usually referred to optimize the operating performance of synchronous reluctance motors are considered. Alternative solutions not usual in literature but specifically investigated for supporting the estimation are also considered, namely constant direct-axis-current and constant direct-axis-flux controls. The flux-observer detects the flux components in the two-phase stationary reference frame by a non-linear model achieved by finite-elements computations. An auxiliary mechanical observer which accounts for the finite-elements mapping of the torque is adjusted by the flux estimation error and provides the rotor position and speed needed for sensorless control. An extended set of experimental tests is presented where the different control methods are compared in terms of position and speed estimation errors and overall control quality. A four poles, three kW synchronous reluctance prototype designed for general industry application is used for testing.

The work developed in this paper presents a comparison between three different phase detection algorithms in order to study the benefits of using each of them when they are applied inside a sensorless rotor position estimation technique. In particular we will analyse the various aspects related to the use of each single algorithm when it is applied into a specific model-based sensorless strategy and when we also take into account the typical impairments affecting the implementation of the real setup, such as unwanted harmonic components and measurement offsets. As a first step a short overview on each phase-detection algorithm under consideration will be given and subsequently the proposed model-based estimation technique will be presented. As a second step the three algorithms are analyzed in detail highlighting their dynamical performances and their robustness properties against implementative knots, in particular through the use of software simulations and real-time simulations reproducing the specific test case of a five-phase motor.