Assessment of a Universal Reconfiguration-less Control Approach in Open-Phase Fault Operation for Multiphase Drives

Multiphase drives have been important in particular industry applications where reliability is a desired goal. The main reason for this is their inherent fault tolerance. Di erent nonlinear controllers that do not include modulation stages, like direct torque control (DTC) or model-based predictive control (MPC), have been used in recent times to govern these complex systems, including mandatory control reconfiguration to guarantee the fault tolerance characteristic. A new reconfiguration-less approach based on virtual voltage vectors (VVs) was recently proposed for MPC, providing a natural healthy and faulty closed-loop regulation of a particular asymmetrical six-phase drive. This work validates the interest in the reconfiguration-less approach for direct controllers and multiphase drives

Field Oriented Control of Multiphase Drives with Passive Fault-Tolerance

Multiphase machines provide continuous operation of the drive with no additional hardware in the event of one or more open-phase faults. This faulttolerant capability is highly appreciated by industry for security and economic reasons. However, the steadystate post-fault operation has only been feasible in previous works after the fault localization and control reconfiguration. Even though this is done at the software stage, the obligation to identify the faulty phases and store the modifications for every fault scenario adds further complexity. This work reveals that this software reconfiguration can be avoided if the field-oriented control (FOC) strategy is designed to satisfactorily handle pre- and post-fault situations. Experimental results confirm the capability to obtain suitable postfault operation without fault localization and control reconfiguration, thus achieving a passive/natural fault tolerance.Ministerio de Ciencia, Innovación y Universidades RTI2018-096151-B-I0

Impact of post-fault flux adaptation on six-phase induction motor drives with parallel converters

The redundancy of multiphase drives provides an inherent fault-tolerant capability that is appreciated in applications with a complicated corrective maintenance or safety-critical requirements. Fault restrictions however force the system to be reconfigured to operate in a smooth and efficient manner. Previous works have been focused on the optimization of current waveforms to generate an undisturbed operation but still maintaining the pre-fault rated flux settings. This work shows that efficient controllers can improve the post-fault performance in six-phase induction machines supplied by parallel- connected converters if offline optimization is used to obtain a variable reference flux. Theoretical and experimental results confirm that the proposed flux adaptation method provides higher torque/power capability, lower degree of imbalance in the current sharing between windings and efficiency improvementMinisterio de Ciencia e Innovación ENE2014-52536-C2-1-R DPI2013- 44278-RJunta de Andalucía P11-TEP-755

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-

Multiphase Current Imbalance Localization Method Applied to Natural Fault- Tolerant Strategies

Multiphase machines are interesting options for high-reliability applications due to their inherent fault tolerance against open-circuit faults (OCFs). Moreover, if the regulation of the x-y currents is realized in open-loop mode using virtual voltage vectors (VVs), the mandatory post-fault control reconfiguration is avoided. The new reconfiguration-less approach was recently defined as a natural/passive fault-tolerant strategy, offering good prospects for industry applications. This work extends the idea to the fault detection (FD) procedure and suggests new settings for the current imbalance localization (CIL) method. The proposal is based on the vector space decomposition (VSD) approach that allows the joint detection of OCFs and stator resistances dissymmetry (RDs). Experimental results in a five-phase induction motor (IM) drive using VVs confirm the viability of the technique

Fault-tolerant Operation of Six-phase Energy Conversion Systems with Parallel Machine-side Converters

The fault tolerance provided by multiphase machines is one of the most attractive features for industry applications where a high degree of reliability is required. Aiming to take advantage of such postfault operating capability, some newly designed full-power energy conversion systems are selecting machines with more than three phases. Although the use of parallel converters is usual in high-power three-phase electrical drives, the fault tolerance of multiphase machines has been mainly considered with single supply from a multiphase converter. This study addresses the fault-tolerant capability of six-phase energy conversion systems supplied with parallel converters, deriving the current references and control strategy that need to be utilized to maximize torque/power production. Experimental results show that it is possible to increase the postfault rating of the system if some degree of imbalance in the current sharing between the two sets of threephase windings is permitted.Ministerio de Ciencia e Innovación ENE2014-52536-C2–1-R DPI2013-44278-RJunta de Andalucía P11-TEP-755

Does the plant defense priming compound β-aminobutyric acid affect the performance of Macrolophus pygmaeus when used to control Bemisia tabaci in tomato?

The β-aminobutyric acid (BABA) is a plant defense priming compound highly effective in controlling important tomato diseases and plant-parasitic nematodes. It has also been shown to induce resistance against phytophagous insects such as aphids. This study examines the effect of BABA on the performance of the tomato pest Bemisia tabaci (MEAM 1, previously known as Biotype B) and its zoophytophagous predator Macrolophus pygmaeus under laboratory and greenhouse conditions. Tomato plants were treated with BABA 25 mM applied by soil drenching. The effect of BABA on the fertility and juvenile development of two generations of B. tabaci and M. pygmaeus was evaluated. Our results showed no effect of BABA on the juvenile development or adult fecundity/fertility of both the whitefly and its predator. The non-interference of BABA with M. pygmaeus and B. tabaci assures that the control of the whitefly with this mirid bug will not be affected when this elicitor is applied to the crop. Further studies are needed to clarify the mechanisms underlying BABA-plant-whitefly-predatory myrids interactions.info:eu-repo/semantics/acceptedVersio

Model Predictive Control based on Dynamic Voltage Vectors for Six-phase Induction Machines

Model predictive control (MPC) has been recently suggested as an interesting alternative for the regulation of multiphase electric drives because it easily exploits the inherent advantages of multiphase machines. However, the standard MPC applies a single switching state during the whole sampling period, inevitably leading to an undesired x y voltage production. Consequently, its performance can be highly degraded when the stator leakage inductance is low. This shortcoming has been, however, mitigated in recent work with the implementation of virtual/synthetic voltage vectors (VVs) in MPC strategies. Their implementation reduces the phase current harmonic distortion since the average x y voltage production becomes null. Nevertheless, VVs have a static nature because they are generally estimated offline, and this implies that the flux/torque regulation is suboptimal. Moreover, these static VVs also present some limitations from the point of view of the dc-link voltage exploitation. Based on these previous limitations, this article proposes the implementation of dynamic virtual voltage vectors (DVVs), where VVs are created online within the MPC strategy. This new concept provides an online optimization of the output voltage production depending on the operating point, resulting in an enhanced flux/torque regulation and a better use of the dc-link voltage. Experimental results have been employed to assess the goodness of the proposed MPC based on DVVs.Ministerio de Ciencia, Innovación y Universidades RTI2018-096151-B-100

Interest and Applicability of Meta-Heuristic Algorithms in the Electrical Parameter Identification of Multiphase Machines

Multiphase machines are complex multi-variable electro-mechanical systems that are receiving special attention from industry due to their better fault tolerance and power-per-phase splitting characteristics compared with conventional three-phase machines. Their utility and interest are restricted to the definition of high-performance controllers, which strongly depends on the knowledge of the electrical parameters used in the multiphase machine model. This work presents the proof-of-concept of a new method based on particle swarm optimization and standstill time-domain tests. This proposed method is tested to estimate the electrical parameters of a five-phase induction machine. A reduction of the estimation error higher than 2.5% is obtained compared with gradient-based approaches.Plan Estatal 2013-2016 Retos - Proyectos I+D+i DPI2013-44278-RPlan Estatal 2013-2016 Retos - Proyectos I+D+i DPI2016-76144-

Open-phase fault operation on multiphase induction 3 motor drives

Hugo Guzman, Ignacio Gonzalez, Federico Barrero and Mario Durán (2015). Open-Phase Fault Operation on Multiphase Induction Motor Drives, Induction Motors - Applications, Control and Fault Diagnostics, Dr. Raul Gregor (Ed.), ISBN: 978-953-51-2207-4, InTech, DOI: 10.5772/60810. Available from: http://www.intechopen.com/books/induction-motors-applications-control-and-fault-diagnostics/open-phase-fault-operation-on-multiphase-induction-motor-drivesMultiphase machines have been recognized in the last few years like an attractive alternative to conventional three-phase ones. This is due to their usefulness in a niche of applications where the reduction in the total power per phase and, mainly, the high overall system reliability and the ability of using the multiphase machine in faulty conditions are required. Electric vehicle and railway traction, all-electric ships, more-electric aircraft or wind power generation systems are examples of up-to-date real applications using multiphase machines, most of them taking advantage of the ability of continuing the operation in faulty conditions. Between the available multiphase machines, symmetrical five-phase induction machines are probably one of the most frequently considered multiphase machines in recent research. However, other multiphase machines have also been used in the last few years due to the development of more powerful microprocessors. This chapter analyzes the behavior of generic n-phase machines (beingn any odd number higher than 3) in faulty operation (considering the most common faulty operation, i.e. the open phase fault). The obtained results will be then particularized to the 5-phase case, where some simulation and experimental results will be presented to show the behavior of the entire system in healthy and faulty conditions. The chapter will be organized as follows: First, the different faults in a multiphase machine are analyzed. Fault conditions are de tailed and explained, and the interest of a multiphase machine in the management of faults is stated. The effect of the open-phase fault operation in the machine model is then studied. A generic n-phase machine is considered, being n any odd number greater than three. The analysis is afterwards particularized to the 5-phase machine, where the open phase fault condition is managed using different control methods and the obtained results are compared. Finally, the conclusions are presented in the last section of the chapter