IEEE Transactions on Industrial Electronics

Volume 56, Number 11, Nov 2009 Access to the journal on IEEE XPLORE IE Transactions Home Page

Special Section on Efficient and Reliable Photovoltaic Systems

56.11.1	G. Spagnuolo, G. Petrone, R. Teodorescu, M. Veerachary, M. Vitelli, "Guest Editor," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4307-4310, Nov 2009. Abstract Link Full Text Abstract: Not Available Special Section Papers
56.11.2	P. Maffezzoni, L. Codecasa, D. D'Amore, "Modeling and Simulation of a Hybrid Photovoltaic Module Equipped With a Heat-Recovery Sys," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4311-4318, Nov 2009. Abstract Link Full Text Abstract: This paper presents a multiphysics model of a hybrid solar panel equipped with a solar concentrator and a cooling interface with heat-recovery capability. It is shown how the temperature profile along the cells can be predicted as a function of the cooling strategy. From this information, the $I$ –$V$ electrical characteristic of the whole module can be derived. An original compact electrothermal macromodel of the photovoltaic module is employed which allows one to properly incorporate the effect of temperature gradients along the cells. By exploiting this macromodel, accurate and efficient electrothermal simulations of the solar system can be carried out with a conventional electrical simulator, like Spice.
56.11.3	G. Velasco-Quesada, F. Guinjoan-Gispert, R. Pique-Lopez, M. Roman-Lumbreras, A. Conesa-Roca, "Electrical PV Array Reconfiguration Strategy for Energy Extraction Improvement in Grid-Connected PV Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4319-4331, Nov 2009. Abstract Link Full Text Abstract: This paper applies a dynamical electrical array reconfiguration (EAR) strategy on the photovoltaic (PV) generator of a grid-connected PV system based on a plant-oriented configuration, in order to improve its energy production when the operating conditions of the solar panels are different. The EAR strategy is carried out by inserting a controllable switching matrix between the PV generator and the central inverter, which allows the electrical reconnection of the available PV modules. As a result, the PV system exhibits a self-capacity for real-time adaptation to the PV generator external operating conditions and improves the energy extraction of the system. Experimental results are provided to validate the proposed approach.
56.11.4	C. Rodriguez, J. D. K. Bishop, "Organic Architecture for Small- to Large-Scale Photovoltaic Power Stati," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4332-4343, Nov 2009. Abstract Link Full Text Abstract: Increased widespread deployment of power generation from photovoltaics is consistent with binding agreements to reduce carbon emissions and increase the penetration of electricity from renewables and political aspirations to increase security of energy supply. However, in order for these generation facilities to compete in increasingly open power markets, they must be low cost and provide high-quality and high-quantity outputs. The organic architecture suggested in this paper proposes a solution that provides these advantages, using modular-power-electronic and energy-storage components, to facilitate scalable plants, from kilowatt to megawatt size. Specifically, the inclusion of power-conversion building blocks (PCBBs), grid-interactive power units (GPUs), and power-system control units allow efficient transfer of power from the point of energy conversion to the point of common coupling. A specific example of a 24-kW plant illustrates that, through optimum switching of PCBBs, the GPU can transfer 95.46% of the daily available energy to the transmission grid.
56.11.5	S. J. Chiang, H.-J. Shieh, M.-C. Chen, "Modeling and Control of PV Charger System With SEPIC Conver," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4344-4353, Nov 2009. Abstract Link Full Text Abstract: The photovoltaic (PV) stand-alone system requires a battery charger for energy storage. This paper presents the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC). The designed SEPIC employs the peak-current-mode control with the current command generated from the input PV voltage regulating loop, where the voltage command is determined by both the PV module maximum power point tracking (MPPT) control loop and the battery charging loop. The control objective is to balance the power flow from the PV module to the battery and the load such that the PV power is utilized effectively and the battery is charged with three charging stages. This paper gives a detailed modeling of the SEPIC with the PV module input and peak-current-mode control first. Accordingly, the PV voltage controller, as well as the adaptive MPPT controller, is designed. An 80-W prototype system is built. The effectiveness of the proposed methods is proved with some simulation and experimental results.
56.11.6	Y.-K. Lo, H.-J. Chiu, T.-P. Lee, I. Purnama, J.-M. Wang, "Analysis and Design of a Photovoltaic System DC Connected to the Utility With a Power Factor Correc," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4354-4362, Nov 2009. Abstract Link Full Text Abstract: This paper presents a photovoltaic (PV) system parallel connected to an electric power grid with a power factor corrector (PFC) for supplying the dc loads. The operation principles and design considerations for the presented PV system are analyzed and discussed. The balanced distribution of the power flows between the utility and the PV panels is achieved automatically by regulating the output dc voltage of the PFC. Experimental results are shown to verify the feasibility of the proposed topology, which can effectively transfer the tracked maximum power from the PV system to the dc load, while the unity power factor is obtained at the utility side.
56.11.7	J. L. Agorreta, L. Reinaldos, R. Gonzalez, M. Borrega, J. Balda, L. Marroyo, "Fuzzy Switching Technique Applied to PWM Boost Converter Operating in Mixed Conduction Mode for PV Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4363-4373, Nov 2009. Abstract Link Full Text Abstract: Due to the variation of the maximum power point (MPP) of photovoltaic (PV) generators with solar radiation and temperature, boost dc–dc converters placed between PV modules and inverters in grid-connected PV systems have to be controlled in a variable operating-point condition. In addition, inductor current dynamics changes suddenly when moving from continuous to discontinuous conduction mode. The previous difficulties make the design of reliable and fast control laws for the input voltage of boost converters complicated. The aim of this paper is to propose a control algorithm based on cascaded-loop control. The input voltage is controlled by the outer loop. The inductor current is controlled by an inner loop strategy which is able to perform in mixed conduction mode, owing to the fuzzy switching technique. Simulation and experimental results for a 10-kW boost converter show that the proposed strategy achieves an accurate and robust performance at every operating point, even if the inductor value varies in a wide range; thus, fast MPP tracking techniques can be implemented. An additional advantage is that constant switching frequency is achieved.
56.11.8	G. Carannante, C. Fraddanno, M. Pagano, L. Piegari, "Experimental Performance of MPPT Algorithm for Photovoltaic Sources Subject to Inhomogeneous Insolat," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4374-4380, Nov 2009. Abstract Link Full Text Abstract: Photovoltaic (PV) power system performance depends on local irradiance conditions. PV systems are sometimes subject to partial shading, which may produce a nonideal characteristic curve, presenting true and local power maxima in the $P$ –$I$ curve. Traditional Maximum Power Point Tracking (MPPT) algorithms can converge to local maximum, which is not the true MPP. In order to solve the problem, this paper investigates the effects of nonuniform solar irradiance distribution on a PV source. An MPPT algorithm that is able to optimize the source instantaneous operating power under nonuniform irradiance is proposed. The ability of the algorithm and its increased performance with respect to traditional algorithms are evaluated by means of experimental tests performed on a real PV power system.
56.11.9	J.-M. Kwon, B.-H. Kwon, K.-H. Nam, "Grid-Connected Photovoltaic Multistring PCS With PV Current Variation Reduction Cont," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4381-4388, Nov 2009. Abstract Link Full Text Abstract: In this paper, a grid-connected photovoltaic (PV) multistring power conditioning system with PV input current reduction control is proposed. An improved maximum power point tracking (MPPT) method for the multistring converter is suggested. The suggested MPPT algorithm tracks the maximum power point even though measurement errors exist. To reduce the PV current variation introduced by the inverter, a PV current variation reduction control is suggested. This PV current variation reduction control reduces the PV current variation without additional components. The low current variation reduces the filter size and improves the MPPT efficiency. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3-kW prototype show high performance such as a MPPT efficiency of 99.7%, an almost unity power factor, a power efficiency of 96.7%, and a total harmonic distortion of 2.0%.
56.11.10	E. Romero-Cadaval, M. I. Milanes-Montero, E. Gonzalez-Romera, F. Barrero-Gonzalez, "Power Injection System for Grid-Connected Photovoltaic Generation Systems Based on Two Collaborative Voltage Source Invert," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4389-4398, Nov 2009. Abstract Link Full Text Abstract: This paper presents a new topology for the power injection system that is based on the parallel association of two voltage source inverters. One operates using a quasi-square voltage waveform strategy, and the other operates with a pulsewidth-modulation (PWM)-based strategy. The aims of this topology are to inject the power from the photovoltaic generation system using the quasi-square inverter and to control the current quality using the PWM inverter. The proposal optimizes the system design, permitting the reduction of system losses and an increase of the energy injected into the grid.
56.11.11	E. Villanueva, P. Correa, J. Rodriguez, M. Pacas, "Control of a Single-Phase Cascaded H-Bridge Multilevel Inverter for Grid-Connected Photovoltaic Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4399-4406, Nov 2009. Abstract Link Full Text Abstract: This paper presents a single-phase cascaded H-bridge converter for a grid-connected photovoltaic (PV) application. The multilevel topology consists of several H-bridge cells connected in series, each one connected to a string of PV modules. The adopted control scheme permits the independent control of each dc-link voltage, enabling, in this way, the tracking of the maximum power point for each string of PV panels. Additionally, low-ripple sinusoidal-current waveforms are generated with almost unity power factor. The topology offers other advantages such as the operation at lower switching frequency or lower current ripple compared to standard two-level topologies. Simulation and experimental results are presented for different operating conditions.
56.11.12	E. Ozdemir, S. Ozdemir, L. M. Tolbert, "Fundamental-Frequency-Modulated Six-Level Diode-Clamped Multilevel Inverter for Three-Phase Stand-Alone Photovoltaic Sys," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4407-4415, Nov 2009. Abstract Link Full Text Abstract: This paper presents a fundamental-frequency-modulated diode-clamped multilevel inverter (DCMLI) scheme for a three-phase stand-alone photovoltaic (PV) system. The system consists of five series-connected PV modules, a six-level DCMLI generating fundamental-modulation staircase three-phase output voltages, and a three-phase induction motor as the load. In order to validate the proposed concept, simulation studies and experimental measurements using a small-scale laboratory prototype are also presented. The results show the feasibility of the fundamental frequency switching application in three-phase stand-alone PV power systems.
56.11.13	G. Grandi, C. Rossi, D. Ostojic, D. Casadei, "A New Multilevel Conversion Structure for Grid-Connected PV Applicati," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4416-4426, Nov 2009. Abstract Link Full Text Abstract: A novel scheme for three-phase grid-connected photovoltaic (PV) generation systems is presented in this paper. The scheme is based on two insulated strings of PV panels, each one feeding the dc bus of a standard two-level three-phase voltage-source inverter (VSI). The inverters are connected to the grid by a three-phase transformer having open-end windings on the inverter side. The resulting conversion structure performs as a multilevel power active filter (equivalent to a three-level inverter), doubling the power capability of a single VSI with given voltage and current ratings. The multilevel voltage waveforms are generated by an improved space-vector-modulation algorithm, suitable for the implementation in industrial digital signal processors. An original control method has been introduced to regulate the dc-link voltages of each VSI, according to the voltage reference given by a single maximum power point tracking controller. The proposed regulation system has been verified by numerical simulations and experimental tests with reference to different operating conditions.
56.11.14	B.-D. Min, J.-P. Lee, J.-H. Kim, T.-J. Kim, D.-W. Yoo, E.-H. Song, "A New Topology With High Efficiency Throughout All Load Range for Photovoltaic ," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4427-4435, Nov 2009. Abstract Link Full Text Abstract: In this paper, a new topology is proposed that can significantly reduce the converter rated power and increase the efficiency of total photovoltaic (PV) system. Since the output voltage of PV module has very wide operating range, in general, the dc/dc converter is used to produce constant high-dc-link voltage for dc/ac inverter. According to the analysis of the proposed topology, only 20% of total PV system power is processed by the dc/dc power conversion stage. The dc/dc power conversion stage used in proposed topology has flat efficiency curve throughout all load range and very high efficiency characteristics. In the proposed topology, because the converter efficiency curve is almost flat throughout all load range, the total system efficiency at light load is dramatically improved. The proposed topology is implemented for 250-kW power conditioning system. This system has only three dc/dc power conversion stage with 24-kW rated power. It is only one-third of total system power. The experimental results show that the proposed topology has good performance.
56.11.15	R. A. Mastromauro, M. Liserre, T. Kerekes, A. Dell'Aquila, "A Single-Phase Voltage-Controlled Grid-Connected Photovoltaic System With Power Quality Conditioner Functional," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4436-4444, Nov 2009. Abstract Link Full Text Abstract: Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV system that provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.
56.11.16	A. Pigazo, M. Liserre, R. A. Mastromauro, V. M. Moreno, A. Dell'Aquila, "Wavelet-Based Islanding Detection in Grid-Connected PV Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4445-4455, Nov 2009. Abstract Link Full Text Abstract: Distributed power generation systems (DPGSs) based on inverters require reliable islanding detection algorithms (passive or active) in order to determine the electrical grid status and operate the grid-connected inverter properly. These methods are based on the analysis of the DPGS voltage, current, and power in time or frequency domain. This paper proposes a time–frequency detection algorithm based on monitoring the DPGS output power considering the influence of the pulsewidth modulation, the output LCL filter, and the employed current controller. Wavelet analysis is applied to obtain time localization of the islanding condition. Simulation and experimental results show the performance of the proposed detection algorithm in comparison with existing methods.
56.11.17	S. Vergura, G. Acciani, V. Amoruso, G. E. Patrono, F. Vacca, "Descriptive and Inferential Statistics for Supervising and Monitoring the Operation of PV Pla," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4456-4464, Nov 2009. Abstract Link Full Text Abstract: This paper deals with the problem of supervising and monitoring a photovoltaic (PV) plant. First, an offline descriptive and inferential statistical procedure for evaluating the goodness of system performance is presented. Then, an online inferential algorithm for real-time monitoring and fault detection is introduced. The two methodologies utilize the energy output of inverters as input data and are valid for both Gaussian and non-normal distribution of data. The procedures have been tested on a real PV installation, and results are reported for the case of a grid-connected PV plant in Italy for which one PV module over 132 resulted in being badly connected.
56.11.18	F. Chan, H. Calleja, "Design Strategy to Optimize the Reliability of Grid-Connected PV Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4465-4472, Nov 2009. Abstract Link Full Text Abstract: This paper presents a strategy, based on the design-of-experiments technique, aimed at optimizing the reliability in inverters for photovoltaic systems. The process involves designing the inverter several times, each time with different specifications, and calculating the reliability for each design. The specifications are established in a systematic manner, in such a way that the parameters with the highest impact are easily identified. The optimization procedure follows a standard reliability estimation methodology and involves modifying the stress factors in a judicious manner. The strategy is exemplified with an integrated boost inverter and a desired mean time between failures of 12 years.
56.11.19	N. Femia, G. Petrone, G. Spagnuolo, M. Vitelli, "A Technique for Improving P&O MPPT Performances of Double-Stage Grid-Connected Photovoltaic Syst," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4473-4482, Nov 2009. Abstract Link Full Text Abstract: In double-stage grid-connected photovoltaic (PV) inverters, the dynamic interactions among the dc/dc and dc/ac stages and the maximum power point tracking (MPPT) controller may reduce the system performances. In this paper, the detrimental effects, particularly in terms of system efficiency and MPPT performances, of the oscillations of the PV array voltage, taking place at the second harmonic of the grid frequency are evidenced. The use of a proper compensation network acting on the error signal between a reference signal provided by the MPPT controller and a signal that is proportional to the PV array voltage is proposed. The guidelines for the proper joint design of the compensation network (which is able to cancel out the PV voltage oscillations) and of the main MPPT parameters are provided in this paper. Simulation results and experimental measurements confirm the effectiveness of the proposed approach.
56.11.20	F. Liu, Y. Zhou, S. Duan, J. Yin, B. Liu, "Parameter Design of a Two-Current-Loop Controller Used in a Grid-Connected Inverter System With LCL Fil," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4483-4491, Nov 2009. Abstract Link Full Text Abstract: LCL filters offer a better choice of attenuating switching frequency harmonics. However, in a grid-connected system, an LCL filter may cause resonance which is a disaster for the system's stability. In order to solve the problem, a two-current-loop control strategy, which includes grid-current outer loop and filter-capacitor-current inner loop, is adopted here. The implementation of this strategy is easy, but the tuning procedure is complex since the outer and inner controllers cannot cooperate well if the parameters of the controllers are not suitable. There is no literature which mentions a method to help give out accurate parameters of the controller. The difficulty of designing the controller is that only two feedbacks cannot provide complete information of a three-order LCL filter. A specific method is proposed in this paper to design the controller. The advantage of this method is to provide a way to maximize the utilization of the two feedbacks to get good system performance through parameter determination. The practicability of the method is tested by using bode diagram, and the antidistortion ability of the system is analyzed. Finally, experimental results verify the availability and correctness of the proposed method.
56.11.21	M. Castilla, J. Miret, J. Matas, L. Garcia de Vicuna, J. M. Guerrero, "Control Design Guidelines for Single-Phase Grid-Connected Photovoltaic Inverters With Damped Resonant Harmonic Compensat," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4492-4501, Nov 2009. Abstract Link Full Text Abstract: The injection of low-harmonic current to the electrical grid is nowadays regulated by international standards. In order to accomplish these standards, selective harmonic compensation is carried out in grid-connected photovoltaic inverters by means of resonant harmonic compensators. This paper gives a systematic design procedure for selecting the gains and parameters of these harmonic compensators. Other factors considered in the design process include frequency deviation, grid synchronization, and transient response. Both a design example meeting the requirements of grid interconnection and selected experimental results from a digital-signal-processor-based laboratory prototype are also reported.
56.11.22	A. Nasiri, S. A. Zabalawi, G. Mandic, "Indoor Power Harvesting Using Photovoltaic Cells for Low-Power Applicati," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4502-4509, Nov 2009. Abstract Link Full Text Abstract: Utilization of low-power indoor devices such as remote sensors, supervisory and alarm systems, distributed controls, and data transfer system is on steady rise. Due to remote and distributed nature of these systems, it is attractive to avoid using electrical wiring to supply power to them. Primary batteries have been used for this application for many years, but they require regular maintenance at usually hard to access places. This paper provides a complete analysis of a photovoltaic (PV) harvesting system for indoor low-power applications. The characteristics of a target load, PV cell, and power conditioning circuit are discussed. Different choices of energy storage are also explained. Implementation and test results of the system are presented, which highlights the practical issues and limitations of the system.
56.11.23	J. C. Vasquez, R. A. Mastromauro, J. M. Guerrero, M. Liserre, "Voltage Support Provided by a Droop-Controlled Multifunctional Inver," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4510-4519, Nov 2009. Abstract Link Full Text Abstract: This paper presents a single-phase multifunctional inverter for photovoltaic (PV) systems application. The converter provides active power to local loads and injects reactive power into the grid providing voltage support at fundamental frequency. The proposed topology is controlled by means of the droop-control technique. Hence, it allows the obtaining of voltage-sag-compensation capability, endowing voltage ride-through to the system. A model and analysis of the whole system is given to properly choose the control parameters. Simulation and experimental results validate the proposed control using a 5-kVA PV converter.
56.11.24	F. Spertino, J. S. Akilimali, "Are Manufacturing $I$– $V$ Mismatch and Reverse Currents Key Factors in Large Photovoltaic Arra," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4520-4531, Nov 2009. Abstract Link Full Text Abstract: In this paper, two factors typical of large photovoltaic (PV) arrays are investigated: one is the current–voltage ( $I$– $V$) mismatch consequent to the production tolerance; the other is the impact of reverse currents in different operating conditions. Concerning the manufacturing $I$–$V$ mismatch, the parameters of the equivalent circuit of the solar cell are computed for several PV modules from flash reports provided by the manufacturers. The corresponding $I$– $V$ characteristic of every module is used to evaluate the behavior of different strings and the interaction among the strings connected for composing PV arrays. Two real crystalline silicon PV systems of 8 $times$ 250 kW and 20 kW are studied, respectively. The simulation results reveal that the impact of the $I$ – $V$ mismatch is negligible with the usual tolerance, and the insertion of the blocking diodes against reverse currents can be avoided with crystalline silicon technology. On the other hand, the experimental results on $I$– $V$ characteristics of the aforementioned arrays put into evidence the existence of a remarkable power deviation (3%–4%) with respect to the rated power, linkable to the lack of measurement uncert- ainty in the manufacturer flash reports. Special Section on Advances In Electrical Machine Monitoring and Diagnosis-Part II
56.11.25	A. Bellini, F. Filippetti, "Guest Editor," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4532-4533, Nov 2009. Abstract Link Full Text Abstract: Not Available Special Section Papers
56.11.26	J. A. Rosero, L. Romeral, J. A. Ortega, E. Rosero, "Short-Circuit Detection by Means of Empirical Mode Decomposition and Wigner–Ville Distribution for PMSM Running Under Dynamic Condit," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4534-4547, Nov 2009. Abstract Link Full Text Abstract: This paper presents and analyzes a method for short-circuit fault detection in a permanent-magnet synchronous motor (PMSM). The study includes steady-state condition and speed transients in motor operation. The stator current is decomposed by empirical mode decomposition (EMD), which generates a set of intrinsic mode functions (IMFs). Quadratic time–frequency (TF) distributions such as smoothed pseudo-Wigner–Ville and Zhao–Atlas–Marks are applied on the more significant IMFs for fault detection. Simulations and experimental laboratory tests validate the algorithms and demonstrate that this kind of TF analysis can be applied to detect and identify short-circuit failures in PMSM.
56.11.27	A. Stefani, A. Bellini, F. Filippetti, "Diagnosis of Induction Machines' Rotor Faults in Time-Varying Conditi," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4548-4556, Nov 2009. Abstract Link Full Text Abstract: Motor current signature analysis is the reference method for the diagnosis of induction machines' rotor faults; however, in time-varying conditions, it fails as slip and speed vary, and, thus, sideband components are spread in a bandwidth that is proportional to the variation. Variable speed drive applications are common in the aerospace, appliance, railway, and automotive industries and also in electric generators for wind turbines. In this paper, a simple and effective method is presented that allows the diagnosis of rotor faults for induction machine drives in time-varying conditions. It is tailored to direct rotor flux field-oriented controlled drives, where the control system provides suitable signals that are exploited for the demodulation to a constant frequency of time-varying signatures related to the rotor faults. Simulations and experiments are reported to validate the proposed method on a critical speed transient.
56.11.28	M. Pineda-Sanchez, M. Riera-Guasp, J. A. Antonino-Daviu, J. Roger-Folch, J. Perez-Cruz, R. Puche-Panadero, "Instantaneous Frequency of the Left Sideband Harmonic During the Start-Up Transient: A New Method for Diagnosis of Broken B," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4557-4570, Nov 2009. Abstract Link Full Text Abstract: In this paper, a new method for detecting the presence of broken rotor bars is presented. The proposed approach is valid for induction machines started at constant frequency and consists of extracting the instantaneous frequency (IF) of the left sideband harmonic (LSH) from the start-up current (LSHst), via the Hilbert transform. It is shown that, in the case of machines with one or several broken bars, the IF of the LSHst exhibits a very characteristic and easy to identify pattern, which is physically justified. This paper also shows that, if the IF of the LSHst is represented against the slip, a universal fault indicator (nondependent neither on the machine characteristics nor on the starting conditions) can be defined. This fault indicator consists of the correlation between the experimental IF of the LSHst and its theoretical evolution. This approach is theoretically introduced and experimentally validated by testing a commercial motor in faulty and healthy conditions, under different operating conditions.
56.11.29	G. R. Bossio, C. H. De Angelo, J. M. Bossio, C. M. Pezzani, G. O. GarcÍa, "Separating Broken Rotor Bars and Load Oscillations on IM Fault Diagnosis Through the Instantaneous Active and Reactive Curre," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4571-4580, Nov 2009. Abstract Link Full Text Abstract: A new method for broken rotor bars and load oscillation diagnosis on induction motors is presented. The proposed strategy is based on the decomposition of the stator currents into their instantaneous active and reactive current components. Such components allow the decoupling of the effects produced by rotor asymmetries from those produced by oscillating loads. This allows not only the proper fault detection but also a correct fault diagnosis. Simulation and experimental results, both from laboratory and industrial cases, are presented to validate the proposal.
56.11.30	A. Khezzar, M. E. K. Oumaamar, M. Hadjami, M. Boucherma, H. Razik, "Induction Motor Diagnosis Using Line Neutral Voltage Signatu," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4581-4591, Nov 2009. Abstract Link Full Text Abstract: This paper presents an analytical approach to shed light on the necessary relationships required for the presence of induction motor diagnosis signatures in the line neutral voltage (the voltage taking place between the supply and the stator neutrals). Special attention is focused on the effect of both space distribution of rotor bars and rotor dissymmetry on the mechanism of generation of diagnosis signatures with consideration of voltage supply unbalance and speed ripples. Generalized and new formulas are proposed, where we can draw a conclusion on the state of the machine. Simulation and experimental results have shown excellent match with theoretically predicted harmonic components.
56.11.31	A. Khezzar, M. Y. Kaikaa, M. E. K. Oumaamar, M. Boucherma, H. Razik, "On the Use of Slot Harmonics as a Potential Indicator of Rotor Bar Breakage in the Induction Mach," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4592-4605, Nov 2009. Abstract Link Full Text Abstract: This paper sheds light on the additional harmonic components arising from broken bars fault in the stator line current of an induction machine, which are generalized and analyzed in a different manner than of those given in the literature. Special attention is focused on the effect of both motor slots and rotor dissymmetry on the mechanism of the generation of the different harmonic components with consideration of the unbalance voltage supply and speed ripples effects. Aside from the well-known diagnosis signatures, new ones show up. The simulation and experimental results confirm the aforementioned study.
56.11.32	M. Drif, A. J. M. Cardoso, "The Use of the Instantaneous-Reactive-Power Signature Analysis for Rotor-Cage-Fault Diagnostics in Three-Phase Induction Mot," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4606-4614, Nov 2009. Abstract Link Full Text Abstract: In this paper, a new detection technique based on the instantaneous-reactive-power signature analysis is proposed for the diagnosis of rotor-cage faults (RCFs) in operating three-phase induction motors (IMs). This technique has been tested through the simulation of two different IMs using a mathematical model based on the winding-function approach. In order to demonstrate the capability of the proposed tool for rotor-condition monitoring, these simulations are complemented by the experimental results obtained from two IMs with several faulty rotors, powered from sinusoidal and nonsinusoidal supply voltages. The results obtained by the fast-Fourier-transform algorithm and the Welch method show the merits of the proposed approach for the detection of RCFs. A suitable fault-severity factor is also proposed as an indicator of the motor condition. Moreover, the inductive reactive effect of RCFs is underlined to demonstrate the effectiveness and convenience of this new technique for the diagnosis of RCFs in three-phase IMs.
56.11.33	H. Razik, M. B. R. Correa, E. R. C. da Silva, "A Novel Monitoring of Load Level and Broken Bar Fault Severity Applied to Squirrel-Cage Induction Motors Using a Genetic Algori," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4615-4626, Nov 2009. Abstract Link Full Text Abstract: This paper deals with the diagnostic of the signature of rotor broken bars when an induction machine is fed or not by an unbalanced line voltage. These signatures are given by the complex spectrum modulus of line current. In order to make the diagnostic, a genetic algorithm is used to keep the amplitude of all faulty lines. Moreover, a fuzzy logic approach allows us to conclude to the load level operating system and to inform the operator of the rotor fault severity. Several experimental results prove the performance of this method under various load levels and various fault severities. Notwithstanding, this approach requires a steady-state operating condition. The conclusion resulting from this paper is highlighted by experimental results which prove the efficiency of the suggested approach.
56.11.34	G. Y. Sizov, A. Sayed-Ahmed, C.-C. Yeh, N. A. O. Demerdash, "Analysis and Diagnostics of Adjacent and Nonadjacent Broken-Rotor-Bar Faults in Squirrel-Cage Induction Machi," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4627-4641, Nov 2009. Abstract Link Full Text Abstract: In this paper, faults associated with the rotor of an induction machine are considered. More specifically, effects of adjacent and nonadjacent bar breakages on rotor fault diagnostics in squirrel-cage induction machines are studied. It is shown that some nonadjacent bar breakages may result in the masking of the commonly used fault indices and, hence, may lead to a possible misdiagnosis of the machine. A discussion of the possible scenarios of these breakages as well as some conclusions regarding the types of squirrel-cage induction machines (number of poles, number of squirrel-cage bars, etc.) that may be more prone to these nonadjacent types of failures are presented. This discussion is supported through both simulation and experimental results. It is also shown that secondary fault effects can be used to diagnose such nonadjacent bar breakages.
56.11.35	P. Zhang, Y. Du, J. Dai, T. G. Habetler, B. Lu, "Impaired-Cooling-Condition Detection Using DC-Signal Injection for Soft-Starter-Connected Induction Mot," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4642-4650, Nov 2009. Abstract Link Full Text Abstract: This paper proposes a monitoring scheme to detect the state of the cooling capability for soft-starter-connected induction motors. Based on the estimated stator-winding temperature via dc-signal injection, the cooling capability of the motor can be monitored online using only voltage and current sensors. The thermal parameters of a simplified thermal model of the induction motor are identified using an extended Kalman filter approach, as an indication of the motor cooling capability. The proposed scheme can warn the users for proactive inspection and maintenance in the case of cooling-condition deterioration. The proposed method has been validated from experimental results under three different cooling conditions and variable-load conditions. The errors of thermal-parameter identification are within 3%. The proposed cooling-condition monitoring scheme, combined with the stator-winding-temperature monitoring scheme, can provide complete thermal protection for soft-starter-connected induction motors.
56.11.36	B. Lu, V. C. Gungor, "Online and Remote Motor Energy Monitoring and Fault Diagnostics Using Wireless Sensor Netwo," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4651-4659, Nov 2009. Abstract Link Full Text Abstract: This paper identifies the synergies between wireless sensor networks (WSNs) and nonintrusive electrical-signal-based motor signature analysis and proposes a scheme of applying WSNs in online and remote energy monitoring and fault diagnostics for industrial motor systems. The main scope is to provide a system overview where the nonintrusive nature of the electrical-signal-based motor signature analysis enables its applications in a WSN architecture. Special considerations in designing nonintrusive motor energy monitoring and fault diagnostic methods in such systems are discussed. This paper also provides detailed analyses to address the real-world challenges in designing and deploying WSNs in practice, including wireless-link-quality dynamics, noise and interference, and environmental impact on communication range and reliability. The overall system feasibility is investigated through a series of laboratory experiments and field tests. First, the concept of a remote and online energy monitoring and fault diagnostic system is demonstrated using a simplified star-type IEEE 802.15.4 compliant WSN in the laboratory. Two well-established nonintrusive motor diagnostic algorithms are intentionally used to prove the feasibility. Next, the challenges of applying the proposed WSN scheme in real industrial environments are analyzed experimentally using field test results.
56.11.37	S. Karimi, A. Gaillard, P. Poure, S. Saadate, "Current Sensor Fault-Tolerant Control for WECS With D," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4660-4670, Nov 2009. Abstract Link Full Text Abstract: The performances of wind energy conversion systems (WECS) heavily depend on the accurate current sensing. A sudden failure in one of the current sensors decreases the system performances. Moreover, if a fault is not detected and handled quickly, its effect leads to system disconnection. Hence, to reduce the failure rate and to prevent unscheduled shutdown, a real-time fault detection, isolation, and compensation scheme could be adopted. This paper introduces a new field-programmable-gate-array (FPGA)-based grid-side-converter current sensor fault-tolerant control for WECS with doubly fed induction generator. The proposed current sensor fault detection is achieved by a predictive model. “FPGA-in-the-loop” and experimental results validate the effectiveness and satisfactory performances of the proposed method.
56.11.38	C. H. De Angelo, G. R. Bossio, S. J. Giaccone, M. I. Valla, J. A. Solsona, G. O. Garcia, "Online Model-Based Stator-Fault Detection and Identification in Induction Mot," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4671-4680, Nov 2009. Abstract Link Full Text Abstract: In this paper, a model-based strategy for stator-interturn short-circuit detection on induction motors is presented. The proposed strategy is based on the generation of a vector of specific residual using a state observer. The vectorial residual is generated from a decomposition of the current estimation error. This allows for a fast detection of incipient faults, independently of the phase in which the fault occurs. Since the observer includes an adaptive scheme for rotor-speed estimation, the proposed scheme can be implemented for online monitoring, by measuring only stator voltages and currents. It is shown that the proposed strategy presents very low sensitivity to load variations and power-supply perturbations. Experimental results are included to show the ability of the proposed strategy for detecting incipient faults, including a low number of short-circuited turns and low fault current.
56.11.39	W. Sleszynski, J. Nieznanski, A. Cichowski, "Open-Transistor Fault Diagnostics in Voltage-Source Inverters by Analyzing the Load Curre," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4681-4688, Nov 2009. Abstract Link Full Text Abstract: A novel method is presented for the detection and isolation of open-transistor faults in voltage-source inverters feeding ac motors. The method is an extension of the normalized dc-components method. The normalized average currents are combined with additional diagnostic variables which convey information about the percentage of time spent by the phase currents in the near-zero zone. The combined diagnostic signals permit much more robust diagnostics of single-transistor faults and make feasible the diagnostics of multiple-transistor faults. Suggested in this paper is also an alternative solution for the normalization of dc components, which is easier interpreted and simpler to implement.
56.11.40	S. H. Kia, H. Henao, G.-A. Capolino, "Torsional Vibration Effects on Induction Machine Current and Torque Signatures in Gearbox-Based Electromechanical Sys," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4689-4699, Nov 2009. Abstract Link Full Text Abstract: The monitoring of heavy-duty electromechanical systems is crucial for their preventive maintenance planning. In these systems, the mechanical anomalies such as load troubles, great torque dynamic variations, and torsional oscillations lead to shaft fatigue and aging of other mechanical parts such as bearings and gearboxes. In this paper, a gearbox-based electromechanical system is investigated. Initially, a simple gearbox dynamic model is used to show the effects of rotating input, output, and mesh frequency components on the electromagnetic torque and consequently on the stator current signature. By this model, the influence of transmission error, eccentricities of pinion/wheel, and teeth contact stiffness variation is demonstrated for a healthy gearbox. Then, it is shown that the electrical machine can be considered as a torque sensor through electromagnetic torque estimation for torsional vibration monitoring without any extra mechanical sensor. A test-rig based on a 5.5-kW three-phase squirrel-cage induction motor connected to a wound-rotor 4-kW induction generator via a one-stage gearbox has been used to validate the proposed method.
56.11.41	B. Trajin, J. Regnier, J. Faucher, "Comparison Between Stator Current and Estimated Mechanical Speed for the Detection of Bearing Wear in Asynchronous Dri," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4700-4709, Nov 2009. Abstract Link Full Text Abstract: This paper deals with the detection of worn rolling bearings in asynchronous machines using electrical measurements and estimated mechanical variables. These two approaches are based on the use of the available electrical quantities, e.g., the machine stator currents, which are often already measured for control and protection purposes. Considering that bearing faults induce load-torque oscillations, a theoretical stator-current model, in case of load-torque oscillations, is recalled. Then, a theoretical estimated rotor flux and estimated speed model demonstrates the presence of harmonics related to load-torque oscillations. Phasemodulation components on stator current and harmonics on estimated speed can be used for detection purposes. The frequency behavior of monitored quantities with regard to the load-torque oscillation frequency is particularly investigated. Fault detectors are then proposed on monitored variables. The efficiency of the indicators is studied for different operating points considering the frequency behavior of the system. Finally, the use of detectors is discussed regarding the supply-frequency range usable for the detection.
56.11.42	F. Immovilli, M. Cocconcelli, A. Bellini, R. Rubini, "Detection of Generalized-Roughness Bearing Fault by Spectral-Kurtosis Energy of Vibration or Current Sign," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4710-4717, Nov 2009. Abstract Link Full Text Abstract: Generalized roughness is the most common damage occurring to rolling bearings. It produces a frequency spreading of the characteristic fault frequencies, thus making it difficult to detect with spectral or envelope analysis. A statistical analysis of typical bearing faults is proposed here in order to identify the spreading bandwidth related to specific conditions, relying on current or vibration measurements only. Then, a diagnostic index based on the computation of the energy in the previously defined bandwidth is used to diagnose bearing faults. The proposed method was validated experimentally with vibration signals, with robust and reliable results. The same procedure can be extended to current signals.
56.11.43	J. Faiz, M. Ojaghi, "Instantaneous-Power Harmonics as Indexes for Mixed Eccentricity Fault in Mains-Fed and Open/Closed-Loop Drive-Connected Squirrel-Cage Induction Mot," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4718-4726, Nov 2009. Abstract Link Full Text Abstract: In this paper, a comprehensive definition of eccentricity fault in cage induction motor is introduced, and instantaneous power is considered as eccentricity-fault index. In addition to the line current, the stator line voltage influences the instantaneous power of the motor; therefore, harmonics of this power can be employed as a fault-diagnosis index when the motor is supplied by a closed-loop control method. It is theoretically shown that the frequencies of harmonics of the instantaneous power due to mixed eccentricity fault are the same for the mains-fed and open/closed-loop drive-connected motors, although the number of factors affecting the amplitudes of the harmonics is relatively large when closed-loop drive connected. A flexible test rig is described, which was established to carry out various measurements on the eccentric motor with different eccentricity degrees, under different supply and control methods, varying load, and variable speeds. The experimental results indicate that the amplitudes of the dominant instantaneous-power harmonics depend on the degrees of mixed-eccentricity static and dynamic components, although these amplitudes are influenced by the supply methods, load level, and speed of the motor.
56.11.44	B. M. Ebrahimi, J. Faiz, M. J. Roshtkhari, "Static-, Dynamic-, and Mixed-Eccentricity Fault Diagnoses in Permanent-Magnet Synchronous Mot," IEEE Trans. on Industrial Electronics, vol. 56, no. 11, pp. 4727-4739, Nov 2009. Abstract Link Full Text Abstract: Mixed-eccentricity (ME) fault diagnosis has not been so far documented for permanent-magnet (PM) synchronous motors (PMSMs). This paper investigates how the static eccentricity (SE), dynamic eccentricity (DE), and ME in three-phase PMSMs can be detected. A novel index for noninvasive diagnosis of these eccentricities is introduced for a faulty PMSM. The nominated index is the amplitude of sideband components with a particular frequency pattern which is extracted from the spectrum of stator current. Using this index makes it possible to determine the occurrence, as well as the type and percentage, of eccentricity precisely. Meanwhile, the current spectrum of the faulty PMSM during a large span is inspected, and the ability of the proposed index is exhibited to detect eccentricity in faulty PMSMs with different loads. A novel theoretical scrutiny based on a magnetic field analysis is presented to prove the introduced index and generalize the illustrated fault recognition method. To show the merit of this index in the eccentricity detection and estimation of its severity, first, the correlation between the index and the SE and DE degrees is determined. Then, the type of the eccentricity is determined by a $k$-nearest neighbor classifier. At the next step, a three-layer artificial neural network is employed to estimate the eccentricity degree and its type. After all, a white Gaussian noise is added to the simulated current, and the robustness of the proposed index is analyzed with respect to the noise variance. In this paper, the PMSM under magnetic fault (demagnetization) and electrical faults (short and open circuits) is modeled, and the current spectrum of the faulty PMSM under demagnetization, short circuit, and open circuit faults is analyzed. It is demonstrated that the proposed index, due to eccentricity fault, is not generated in the current spectrum due to magnetic and electrical faults. - Indeed, it is exposed that the introduced index is only created due to eccentricity fault and it is not sensitive to other faults. To model the PMSM eccentricities, a time-stepping finite-element method, which takes into account all geometrical and physical characteristics of the machine components, nonuniform permeance of the air gap, and nonuniform characteristics of the PM material, is employed. This model facilitates the access to the demanded signals in order to have accurate processing. A comparison of simulation and experimental results validate the proposed index.