A New Laboratory for Hands-on Teaching of Electrical Engineering

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper describes an innovative laboratory for students in Electrical Engineering courses, which is recently established at the Energy Department of Politecnico di Torino, Italy. The main peculiarities of the lab are the high ICT content of each test rig, the multidisciplinary experiences, and the hands-on teaching methodology, allowing the student to have access in overall safety to many complex electrical/electromechanical systems. Currently, eight courses of Bachelor and Master of Science degrees in electrical engineering carry out in-class exercises and hands-on experiments in the new lab, serving over 200 students in total per year. The innovative lab also allows for external collaborations with companies and institutions for specific (and in some cases permanent) training offers, like a one-day per month LabVIEW course for faculty and staff members of Politecnico di Torino

Comparison of Superposition Equivalent Loading Methods for Induction Machine Temperature Tests

The superposition equivalent loading method proposed by international standards for testing induction machines allows to conduct temperature tests at reduced different conditions than rated and extrapolate the results to rated values. Much as this test is suitable for large machines that test facilities lack capacity to test, the principle is also applicable to small machines. However, its applicability to small machines has not been extensively studied yet. Furthermore, the three types of the method categorized in the standard IEEE 112-2017 have not been compared to establish their equivalence or otherwise. This paper reports an extensive test campaign on different small size induction motors to determine both the applicability of the method to small machines and to compare the equivalence of the three types of approach. Multiple reduced voltage and reduced current selections have also been investigated to assess the accuracy of the methods for different test conditions. Test results show that all the three alternative loading methods proposed by the standard seems to be practically equivalent, whit a goodness of fit of the obtained results that tends to improve as the machine rating increases

Efficiency Analysis of PWM Inverter Fed Three-Phase and Dual Three-Phase High Frequency Induction Machines for Low/Medium Power Applications

A performance analysis of three-phase and dual three-phase (DTP) induction pulsewidth modulation (PWM) inverter-fed motor drives is conducted in this paper. The focus is on the efficiency performance of high-frequency DTP machines compared to their three-phase counterparts in low/medium power applications. For this purpose, a DTP machine, having two sets of stator three-phase windings spatially shifted by 30 electrical degrees (asymmetrical six-phase winding configuration), was tested for both six-phase and three-phase winding configurations under the same magnetic conditions. Simulation and experimental results are presented to evaluate the efficiency performance of three-phase and dual-three induction motor drives employing PWM voltage source inverters

Erratum: Noninvasive Measurements and FEM Analyses for Estimating the Rotor Bar-Lamination Contact Resistance (IEEE Trans. Ind. Appl. (2021) 57: 1 (208-217) DOI: 10.1109/tia.2020.3028347)

In [1], the correct author affiliations should read: Z. Gmyrek is with the Institute of Mechatronics and Information Systems, Lodz University of Technology, Lodz 90-924, Poland (e-mail: [email protected]). S. Vaschetto, M. Ahmadi Darmani, and A. Cavagnino are with the Politecnico di Torino, Dipartimento Energia, Turin 10129, Italy (e-mail: [email protected]; [email protected]; andrea. [email protected])

Superconductivity and its Application in the Field of Electrical Machines

This paper provides a review on the most recent applications of superconductors in rotating electrical machines. The main types of superconductors for the present-day electrical applications are shown to highlight their main features. The main characteristics of superconducting synchronous machines, DC machines and induction machines for marine and vehicle propulsion, future electric aircraft, wind energy and industrial applications are discussed by presenting data of prototypes and demonstrators. The paper aims to raise awareness among researchers and engineers on the importance of superconductivity to enhance the performance of conventional electrical machines

Iron Losses and Parameters Investigation of Multi-Three-Phase Induction Motors in Normal and Open-Phase Fault Conditions

Among multi-phase solutions, multi-three-phase induction machines (IMs) are gaining an increasing interest in the industry due to their advantages to be configured as multiple three-phase units simultaneously on the same magnetic circuit. According to this scenario, the identification of the equivalent circuit parameters and conventional iron losses covers a key role in evaluating performance and efficiency, especially when the machine is operated in a wide torque-speed range. Therefore, the goal of this paper is to investigate the core losses and the saturation phenomena of multi-three-phase IMs operated in normal and open-three-phase fault conditions under different harmonic contents of the air-gap magnetomotive force. A procedure to identify the parameters of the equivalent circuit of the machine in faulty conditions is reported. Experimental results are presented on a 12-phase asymmetrical IM featuring a quadruple three-phase stator winding. Finally, a comparison between normal and faulty conditions in terms of efficiency and losses for several machine working points is reported

Approaches for Improving Lumped Parameter Thermal Networks for Outer Rotor SPM Machines

This work is about the transient modeling of the thermal characteristics of outer rotor SPM machines by considering a lumped parameter thermal network based approach. The machine considered here poses particular challenges for the modeling, e.g., due to the semi-closed stator surrounded by a rotor bell that provides a speed-dependent cooling of the stator coils. Starting from a simpler basic network configuration, model extensions and refinements are presented and discussed. The subsequent parameter identification is done by means of an initial design of experiments based sampling, and a subsequent single-objective and also a multi-objective optimization of error functions for the components' temperatures. Analyzing the therefrom derived Pareto fronts and the consequent tradeoff regarding achievable minimum modeling errors for different system's components gives insights into where and how the modeling can be further improved. All the investigations are based on experimental results obtained through operating a particularly developed test setup

Measurement-Based Identification of Lumped Parameter Thermal Networks for sub-Kw Outer Rotor PM Machines

This work is on deriving precise lumped parameter thermal networks for modeling the transient thermal characteristics of electric machines under variable load conditions. The goal is to facilitate an accurate estimation of the temperatures of critical machines' components and to allow for running the derived model in real time to adapt the motor control based on the load history and maximum permissible temperatures. Consequently, the machine's capabilities can be exhausted at best considering a highly-utilized drive. The model shall be as simple as possible without sacrificing the exactness of the predicted temperatures. Accordingly, a specific lumped parameter thermal network topology was selected and its characteristics are explained in detail. The measurement data based optimization of its critical parameters through an evolutionary optimization strategy, and the therefore utilized experimental setup will be described in detail here. Measurement cycles were recorded for modeling and verification purposes including both static and dynamic test cycles with changing load torque and speed requirements. Applying the proposed hybrid approach for determining the model's parameters through involving physics-based equations as well as numerical optimization followed a significant improvement of the preciseness of the predicted motor temperatures compared to solely determining the networks's coefficients based on expert knowledge. Thereby, the validation included both the original measurement data as well as extra measurement runs. The proposed and applied strategy provides an excellent basis for future thermal modeling of electric machines