Modern Diagnostics Techniques for Electrical Machines, Power Electronics, and Drives

© 2015 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng 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.[EN] For the last ten years, at least three different special sections dealing with diagnostics in power electrical engineering have been published in the IEEE transactions on industrial electronics [1]-[5]. All of them had their specificities, but the last ones, starting in 2011, were more connected to relevant events organized on the topic. In fact, these events have been clearly the only international forums fully dedicated to diagnostics techniques in power electrical engineering. For this particular issue, it has been decided to separate the different submissions into six parts: state of the art; general methods; induction machines (IMs); synchronous machines (SMs); . electrical drives; power components and power converters. The second section includes only one state-of-the-art paper, which is dedicated to actual techniques implemented in both industry and research laboratories. The third section includes three papers on diagnostic techniques not specifically aimed at a particular type of machine. The fourth section includes three papers devoted to diagnostics of rotor faults, two dedicated to stator insulation issues, and four papers dealing with mechanical faults diagnosis in IMs. The fifth section includes papers focusing on different types of SMs. The first two papers deal with wound-rotor SMs, the following three papers are dedicated to permanent-magnet radial flux machines, and the last one deals with permanent-magnet axial flux machines. Regarding the types of faults analyzed, there are three papers devoted to the diagnosis of interturn short circuits in the stator windings, i.e., one dedicated to the detection and location of field-winding-to-ground faults and a paper devoted to the diagnosis of static eccentricities. In the sixth section, two papers investigate issues related to faults in drive sensors, and one is devoted to fault detections in the coupling inductors. The last section includes two papers devoted to diagnosis of faults and losses analysis in switching components of power converters.Capolino, G.; Antonino-Daviu, J.; Riera-Guasp, M. (2015). Modern Diagnostics Techniques for Electrical Machines, Power Electronics, and Drives. IEEE Transactions on Industrial Electronics. 62(3):1738-1745. doi:10.1109/TIE.2015.2391186S1738174562

Multiphase electric drives for "More Electric Aircraft" applications

Advances in power electronic and machine control techniques are making the inverter-fed drives an always more attractive solution. Because of the number of inverter legs is arbitrary, also the number of phases results as a further degree of freedom for the machine design. Therefore, the multiphase winding is often a possible solution. Due to the increasing demand for high performance and high power variable speed drives, the research on multiphase machines has experienced a significant growth in the last two decades. Indeed, one of the main advantages of the multiphase technology is the possibility of splitting the power of the system across a higher number of power electronic devices with a reduced rating. A similar result can be obtained by using multi-level converters. However, the redundancy of the phases leads to an increased reliability of the machine and to the introduction of additional degrees of freedom in the current control and the machine design. This work aims to study and analyze the highly reliable and fault tolerant machines. It proposes innovative solutions for multiphase machine design and control to meet the safety-critical requirements in “More-Electric Aircraft” (MEA) and “More Electric Engine” (MEE) in which thermal, pneumatic or hydraulic drives in aerospace applications are replaced with electric ones. Open phase, high resistance and short circuit faults are investigated. Fault tolerant controls and fault detection algorithms are presented. Radial force control techniques and bearingless operation are verified and improved for various working scenarios. Fault tolerant designs of multiphase machines are also proposed

An open-phase fault detection method for six-phase induction motor drives

Malaga (Spain), 4th to 6th April, 2017 Comunicaciones del Congreso Publicadas en: Renewable Energy and Power Quality Journal (RE&PQJ) ISSN 2172 038X, No.15 April 2017Induction machines (IM) with multiple sets of three-phase windings are a real alternative in safety- critical applications due to their inherent redundancy and extra number of freedom degrees. These properties can be used to devel op a fault-tolerant system without extra hardware. The fault detection is mandatory in the creation of a fault tolerant system. Since, the fault localization allows to adapt the control scheme of this anomalous mode of operation. Nowadays, open-phase faults (OPFs) and six-phase IMs are hot topics in the literature of fault-tolerant drives. Thus, this paper presents an open-phase fault detection method for a six-phase IM drive . The detection method is based o n the vector space decomposition (VSD), taking the components of the secondary orthogonal subspace to localize the open-phase fault. The goodness of the proposed method is validated with simulation resultsMinisterio de Ciencia e Innovacion ENE2014-52536-C2–1-

Stator Interturn Fault Detection in Permanent-Magnet Machines Using PWM Ripple Current Measurement

This paper proposes a novel method of interturn fault detection based on measurement of pulsewidth modulation (PWM) ripple current. The method uses the ripple current generated by the switching inverter as a means to detect interturn fault. High-frequency (HF) impedance behavior of healthy and faulted windings is analyzed and modeled, and ripple current signature due to interturn faults is quantified. A simple analog circuit is designed to extract the PWM ripple current via a bandpass (BP) filter and a root-mean-square (RMS) detector for fault detection. In addition, this method can also identify the faulted phase, which can be used for fault mitigation strategies. The method is tested experimentally on a five-phase permanent-magnet (PM) machine drive

PWM Ripple Currents Based Turn Fault Detection for Multiphase Permanent Magnet Machines

Most permanent magnet machines are driven by inverters with pulse width modulation (PWM) voltages. The currents contain high frequency (HF) components which are inversely proportional to machine inductance. The HF PWM ripple currents can be used to detect a turn fault that gives rise to changes in inductance. The features of these HF components in turn fault conditions are analyzed. A bandpass (BP) filter is designed to extract the selected sideband components, and their root-mean-square (RMS) values are measured. The RMS values in all phases are compared. It is shown that the RMS ripple current ratios between two adjacent phases provide a very good means of detecting turn fault with high signal-to-noise ratio. The detection method can identify the faulted phase, tolerate inherent imbalance of the machine, and is hardly affected by transient states. The method is assessed by simulations and experiments on a five-phase permanent magnet machine

Novel approach to fault-tolerant control of inter-turn short circuits in permanent magnet synchronous motors for UAV propellers

This paper deals with the development of a novel fault‐tolerant control technique aiming at the diagnosis and accommodation of inter‐turn short circuit faults in permanent magnet synchronous motors for lightweight UAV propulsion. The reference motor is driven by a four‐leg converter, which can be reconfigured in case of a phase fault by enabling the control of the central point of the motor Y‐connection. A crucial design point entails the development of fault detection and isolation (FDI) algorithms capable of minimizing the failure transients and avoiding the short circuit extension. The proposed fault‐tolerant control is composed of two sections: the first one applies a novel FDI algorithm for short circuit faults based on the trajectory tracking of the motor current phasor in the Clarke plane; the second one implements the fault accommodation, by applying a reference frame transformation technique to the post‐fault commands. The control effectiveness is assessed via nonlinear simulations by characterizing the FDI latency and the post‐fault performances. The proposed technique demonstrates excellent potentialities: the FDI algorithm simultaneously detects and isolates the considered faults, even with very limited extensions, during both stationary and unsteady operating conditions. In addition, the proposed accommodation technique is very effective in minimizing the post‐fault torque ripples

Diagnosis and Fault detection in Electrical Machines and Drives based on Advanced Signal Processing Techniques

In the present thesis, a new methodology of diagnosis based on advanced use of time-frequency technique analysis is presented. More precisely, a new fault index that allows tracking individual fault components in a single frequency band is defined. More in detail, a frequency sliding is applied to the signals being analyzed (currents, voltages, vibration signals), so that each single fault frequency component is shifted into a prefixed single frequency band. Then, the discrete Wavelet Transform is applied to the resulting signal to extract the fault signature in the frequency band that has been chosen. Once the state of the machine has been qualitatively diagnosed, a quantitative evaluation of the fault degree is necessary. For this purpose, a fault index based on the energy calculation of approximation and/or detail signals resulting from wavelet decomposition has been introduced to quantify the fault extend. The main advantages of the developed new method over existing Diagnosis techniques are the following: - Capability of monitoring the fault evolution continuously over time under any transient operating condition; - Speed/slip measurement or estimation is not required; - Higher accuracy in filtering frequency components around the fundamental in case of rotor faults; - Reduction in the likelihood of false indications by avoiding confusion with other fault harmonics (the contribution of the most relevant fault frequency components under speed-varying conditions are clamped in a single frequency band); - Low memory requirement due to low sampling frequency; - Reduction in the latency of time processing (no requirement of repeated sampling operation)