A field-oriented armature-input-voltage output-feedback control approach is proposed for the robust linear controller design on an induction motor. The scheme simultaneously solves an angular-velocity reference-trajectory tracking task and a flux magnitude regulation in the presence of arbitrary time-varying load torques and unknown nonlinearities. The field-oriented input-voltage scheme is combined with linear high-gain asymptotic observers, of the generalized proportional-integral type, and linear active-disturbance-rejection output-feedback controllers. The linear observers online estimate, in a simultaneous manner, the output phase variables and the lumped effects of the following: 1) unknown time-varying load torques and unmodeled frictions and 2) rather complex state-dependent nonlinearities present in the electric and magnetic circuits. The field-oriented part of the scheme uses the classical flux observer or simulator. The proposed control laws naturally decouple, while linearizing, the extended second-order dynamics for the angular velocity and the squared flux magnitude. The proposed control scheme is here tested on an experimental induction motor setup.

In this article, the parameter identification of a brushless DC motor (BLDC) is presented. The approach here presented is based on a direct identification considering a three-phase line-to-line voltage electromagnetic torque as function of the electric currents and rotor speed. The estimation is divided into two stages. First, the electrical parameters are estimated by well-known no-load and DC tests. Consequently, estimation of mechanical parameters is performed using a recursive Least Square Algorithm. The proposed approach is validated by comparing model responses to motor real time responses. Additionally, the design, digital simulation and real time implementation of a PI rotor speed controller, based on the estimated model, validate the identification proposal presented here.

High-temperature superconductors (HTS) are greatly appealing for the development of high efficient, and high energy density power devices. They are particularly relevant for applications requiring light and compact machines such as wind power generation. In this context, to ensure the proper design of the superconducting machines and their reliable operation in power systems, it is then important to develop models that can accurately include their physics but also can describe properly their interaction with the system. To achieve such a goal, one approach is the co-simulation. This numerical technique can bring fine geometrical and physical details of the machines through a finite element model (FEM) meanwhile dealing with the operation of the whole system that incorporates the machine and a subset of the power grid represented by an external electrical circuit. The goal of the present work is to put to use this numerical technique when superconducting components are involved. Here, a case study is proposed involving a 15 MW hybrid superconducting synchronous generator (HTS rotor and conventional stator) coupled to a direct current network via a rectifier and its associated filter. The case study related to wind power application allows grasping the technical issues when employing co-simulation dealing with HTS machines. The FEM of the generator is done in the commercial software COMSOL Multiphysics, which interacts with the circuit simulator Simulink through the built-in Functional Mock-up Unit. For the present study, a new version of the latest J–A formulation combined with homogenization technique is introduced allowing an even faster computation time compared to the T–A formulation. Distributed variables and global variables such as current density, magnetic flux density, and local losses for the former and voltage, current, electromagnetic torque, and power quality for the latter are estimated and compared for both formulations. The idea is to find the best-suited combination FEM-circuit under criteria of computational speed, accuracy, and numerical stability. Thus, it is shown that all formulations generate an error of less than 5% on the machine parameters and that the J–A formulation with first order elements stands out with a significant 4-fold reduction in computational costs.

The present work proposes a nonlinear model of a buck–boost DC-DC power converter considering the nonlinear magnetic characteristics of the power inductor and electrical losses of the system. The Euler–Lagrange formalism is used for formulating the proposed model. Previous research works have reported mathematical models to describe power inductor dynamics. However, a gap in the literature remains regarding modeling this kind of element when it operates within power converters. Also, a linear-based controller scheme is proposed to regulate a non-ideal buck–boost DC-DC power converter. A methodology for tuning the proposed controller is presented, which considers the nonlinear model structure of the power converter, the linearization procedure based on an identification process, and a frequency domain analysis based on the approximated linear model. Finally, the tuned control scheme is tested on the nonlinear model of the power converter under several operational conditions showing excellent performance by effectively regulating the output voltage. The results are compared with those derived from alternative control strategies, and a better performance is generally obtained.

Eddy currents are an electromagnetic phenomenon that represent an inexhaustible source of inspiration for technological innovations in the 21st century. Throughout history, these currents have been a subject of research and technological development in multiple fields. This article delves into the fascinating world of eddy currents, revealing their physical foundations and highlighting their impact on a wide range of applications, ranging from non-destructive evaluation of materials to levitation phenomena, as well as their influence on fields as diverse as medicine, the automotive industry, and aerospace. The nature of eddy currents has stimulated the imaginations of scientists and engineers, driving the creation of revolutionary technologies that are transforming our society. As we progress through this article, we will cover the main aspects of eddy currents, their practical applications, and challenges for future works.

Induction stoves are increasingly recognized as the future of cooking technology due to their numerous benefits, including enhanced energy efficiency, improved safety, and precise cooking control. This paper provides a comprehensive review of the key technological advancements in induction stoves, while also examining the societal and health impacts that need to be addressed to support their widespread adoption. Induction stoves operate based on the principle of eddy currents induced in metal cookware, which generate heat directly within the pot, reducing cooking times and increasing energy efficiency compared with conventional gas and electric stoves. Moreover, induction stoves are considered an environmentally sustainable option, as they contribute to improvements in indoor air quality by reducing emissions associated with fuel combustion during cooking. However, ongoing research is essential to ensure the safe and effective use of this technology on a broader scale.