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This paper develops and analyzes a parametric model for simulating healthy and faulty surface-mounted permanent magnet synchronous motors. It allows studying the effects of stator winding interturn short-circuit faults. A relevant feature of the developed model is that it deals with spatial harmonics due to a nonsinusoidal rotor permanent magnet configuration. Additionally, the proposed model is valid for studying the behavior of these machines running under nonstationary conditions, including load or speed variations. Stator current spectra obtained from simulations performed by applying the proposed model show a close similitude with experimental results, highlighting the potential of such a model to understand the effects of stator winding failures on the current spectrum and allowing it to carry out an automatic diagnosis of such faults.

Permanent magnet synchronous motors (PMSMs) are applied in high performance positioning and variable speed applications because of their enhanced features with respect to other AC motor types. Fault detection and diagnosis of electrical motors for critical applications is an active field of research. However, much research remains to be done in the field of PMSM demagnetization faults, especially when running under non-stationary conditions. This paper presents a time–frequency method specifically focused to detect and diagnose demagnetization faults in PMSMs running under non-stationary speed conditions, based on the Hilbert Huang transform. The effectiveness of the proposed method is proven by means of experimental results.

This paper develops an estimator of the kinematics of the movable parts of any AC powered contactor. This estimator uses easily measurable electrical variables such as the voltage across the coil terminals and the current flowing through the main coil of the contactor. Hence, a low cost microcontroller would be able to implement a control algorithm in order to reduce the undesirable phenomenon of contact bounce, which causes severe erosion of the contacts and dramatically reduces the electrical life and reliability of the contacts. To develop such an estimator is essential to have at our disposal a robust model of the contactor. Therefore, a rigorous parametric model that allows us to predict the dynamic response of the AC contactor is proposed. It solves the mechanic and electromagnetic coupled differential equations that govern the dynamics of the contactor by applying a Runge–Kutta-based solver. Several approaches have been described in the technical literature. Most of them are based on high cost computational finite elements method or on simplified parametric models. The parametric model presented here takes into account the fringing flux and deals with shading rings interaction from a general point of view, thus avoiding simplified assumptions. Copyright © 2008 John Wiley & Sons, Ltd.

This paper presents the results of our study of the permanent-magnet synchronous motor (PMSM) running under demagnetization. We examined the effect of demagnetization on the current spectrum of PMSMs with the aim of developing an effective condition-monitoring scheme. Harmonics of the stator currents induced by the fault conditions are examined. Simulation by means of a two-dimensional finite-element analysis (FEA) software package and experimental results are presented to substantiate the successful application of the proposed method over a wide range of motor operation conditions. Methods based on continuous wavelet transform (CWT) and discrete wavelet transform (DWT) have been successfully applied to detect and to discriminate demagnetization faults in PMSM motors under nonstationary conditions. Additionally, a reduced set of easy-to-compute discriminating features for both CWT and DWT methods has been defined. We have shown the effectiveness of the proposed method by means of experimental results.

This paper describes a novel algorithm for a closed-loop sensorless control of electromagnetic devices. It integrates a novel fault diagnosis algorithm of the whole electromagnetic circuit. Applied to a contactor with a dc core, it eliminates the armature and contact bounce, whether it is ac or dc powered and at either 50 or 60 Hz. The position and velocity of the moving armature and contacts are calculated by means of the online determination of the inductance using only the measured current and voltage values of the contactor coil as control inputs. A fuzzy controller takes the position and velocity of the armature as input and provides the current set point as output, which controls the velocity of closure of the contacts. The algorithm has been implemented in a low-cost electronic module.

We propose a new closed-loop sensorless method for reducing contact bounce on closure of a contactor. Several approaches to the problem have already been described; most of them use some kind of sensor to establish the position and speed of the contacts in real time, whereas in our approach, the position and speed of the moving armature and contacts are calculated by using only the current and voltage values of the contactor coil as control inputs. A fuzzy controller takes as input the position and velocity of the armature and provides as output an intensity set point that controls the velocity of the closure of the contacts. Furthermore, we have developed a low-cost electronic module that implements the control system and integrates it in the contactor. The module eliminates the bounces completely and thus prevents the contacts from repeatedly making and breaking the circuit.

This paper presents a rigorous model to simultaneously solving the mechanic and electromagnetic coupled differential equations which govern the dynamic response of the contactor. The model is validated with data obtained experimentally and therefore the accuracy of the model is validated. On the other hand, an estimator of the position and the velocity of the contacts, as well as of the moving core is developed. This estimator only uses available electrical variables, such as the voltage across the coil terminals and the current flowing through the coil of the contactor. Hence, by this way, a low cost microcontroller could be able to implement a control algorithm in order to reduce the undesirable phenomenon of the contact bounce, which causes severe erosion of the contacts and, as a consequence, the electrical life and reliability of the contacts are greatly reduced.