IEEE Transactions on Industrial Electronics 

Volume 55,  Number 5, May 2008           Access to the journal on IEEE XPLORE     IE Transactions Home Page



                 Special Section Papers
55.5.1    "Table of Contents," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. C1-1890, May 2008.   Abstract Link    Full Text

Abstract: Not Available

55.5.2    "IEEE Transactions on Industrial Electronics publication information," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. C2-C2, May 2008.   Abstract Link    Full Text

Abstract: Not Available

55.5.3    E. Levi, "Guest Editorial," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1891-1892, May 2008.   Abstract Link    Full Text

Abstract: The thirteen papers in this special section focus on multiphase machines and drives. The first paper is of a survey type. The remaining twelve can be roughly classified into three groups: 1) PWM methods for power electronic converters with a multiphase output; 2) fault-tolerant control schemes; and 3) various issues in multiphase drive systems. There are four papers in each group.

55.5.4    E. Levi, "Multiphase Electric Machines for Variable-Speed Applications," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1893-1909, May 2008.   Abstract Link    Full Text

Abstract: Although the concept of variable-speed drives, based on utilization of multiphase machines, dates back to the late 1960s, it was not until the mid- to late 1990s that multiphase drives became serious contenders for various applications. These include electric ship propulsion, locomotive traction, electric and hybrid electric vehicles, ldquomore-electricrdquo aircraft, and high-power industrial applications. As a consequence, there has been a substantial increase in the interest for such drive systems worldwide, resulting in a huge volume of work published during the last ten years. An attempt is made in this paper to provide a brief review of the current state of the art in the area. After addressing the reasons for potential use of multiphase rather than three-phase drives and the available approaches to multiphase machine designs, various control schemes are surveyed. This is followed by a discussion of the multiphase voltage source inverter control. Various possibilities for the use of additional degrees of freedom that exist in multiphase machines are further elaborated. Finally, multiphase machine applications in electric energy generation are addressed.

55.5.5    K. Marouani, L. Baghli, D. Hadiouche, A. Kheloui, A. Rezzoug, "A New PWM Strategy Based on a 24-Sector Vector Space Decomposition for a Six-Phase VSI-Fed Dual Stator Induction Motor," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1910-1920, May 2008.   Abstract Link    Full Text

Abstract: This paper presents a new space vector pulsewidth modulation (SVPWM) technique for the control of a six-phase voltage source inverter (VSI)-fed dual stator induction machines (DSIM). A DSIM is an induction machine which has two sets of three-phase stator windings spatially shifted by 30 electrical degrees and fed by two three-phase VSIs. Despite their advantage of power segmentation, these machines are characterized by large zero sequence harmonic currents, and in particular those of order 6 k plusmn 1, which are due to the mutual cancellation between the two stator windings. The proposed SVPWM scheme, while easy to implement digitally, reduces significantly these extra stator harmonic currents. Experimental results, collected from a 15 kW prototype machine controlled by a digital signal processor, are presented and discussed.

55.5.6    D. Casadei, D. Dujic, E. Levi, G. Serra, A. Tani, L. Zarri, "General Modulation Strategy for Seven-Phase Inverters With Independent Control of Multiple Voltage Space Vectors," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1921-1932, May 2008.   Abstract Link    Full Text

Abstract: This paper focuses on the analysis of a seven-phase voltage-source inverter for high-performance motor drives. The problem of the modulation strategy of the inverter is solved by combining the multiple space vector representation with traditional carrier-based pulsewidth modulation. This approach leads to the definition of a general modulation strategy that can be usefully utilized in multimotor drives, as well as in multiphase motor drives for improving the torque density. The inverter output voltage capability is investigated, showing that the proposed modulation strategy is able to fully exploit the dc input voltage either in sinusoidal or nonsinusoidal operating conditions. The results obtained in the analytical investigation are confirmed by experimental tests.

55.5.7    O. Lopez, J. Alvarez, J. Doval-Gandoy, F.D. Freijedo, "Multilevel Multiphase Space Vector PWM Algorithm," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1933-1942, May 2008.   Abstract Link    Full Text

Abstract: In the last few years, interest in multiphase converter technology has increased due to the benefits of using more than three phases in drive applications. Besides, multilevel converter technology permits the achievement of high power ratings with voltage limited devices. Multilevel multiphase technology combines the benefits of both technologies, but new modulation techniques must be developed in order to take advantage of multilevel multiphase converters. In this paper, a novel space vector pulsewidth modulation (SVPWM) algorithm for multilevel multiphase voltage source converters is presented. This algorithm is the result of the two main contributions of this paper: the demonstration that a multilevel multiphase modulator can be realized from a two-level multiphase modulator, and the development of a new two-level multiphase SVPWM algorithm. The multiphase SVPWM algorithm presented in this paper can be applied to most multilevel topologies; it has low computational complexity and it is suitable for hardware implementations. Finally, the algorithm was implemented in a low-cost field-programmable gate array and it was tested in a laboratory with a real prototype using a five-level five-phase inverter.

55.5.8    D. Dujic, G. Grandi, M. Jones, E. Levi, "A Space Vector PWM Scheme for Multifrequency Output Voltage Generation With Multiphase Voltage-Source Inverters," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1943-1955, May 2008.   Abstract Link    Full Text

Abstract: Multiphase variable-speed drives, supplied from two-level voltage-source inverters (VSIs), are nowadays considered for various industrial applications. Depending on the drive structure and/or the motor design, the VSI is required to generate either sinusoidal voltages or voltages that contain a certain number of sinusoidal components (ldquomultifrequency output voltagesrdquo). The existing space vector pulsewidth-modulation (SVPWM) schemes are based on selection of (n-1) active space vectors (for odd phase numbers) within a switching period and they yield either sinusoidal voltage or sinusoidal fundamental voltage in combination with a limited amount of other harmonic terms. This paper develops a SVPWM scheme, which enables multifrequency output voltage generation with arbitrary values of various sinusoidal components in the output voltage. The method is based on initial selection of (n-1)2/2 active space vectors within a switching period, instead of the common (n-1) active vectors. By properly arranging the sequence of the vector application, it is possible to provide an automatic postreduction of the number of applied active vectors to (n-1), thus maintaining the same switching frequency as with the existing schemes while simultaneously avoiding the limiting on the generated sinusoidal output voltage components. Theoretical considerations are detailed using a five-phase VSI. The experimental verification is provided using a five-phase two-motor series-connected induction motor drive, supplied from a custom-designed five-phase DSP-controlled VSI.

55.5.9    M.-A. Shamsi-Nejad, B. Nahid-Mobarakeh, S. Pierfederici, F. Meibody-Tabar, "Fault Tolerant and Minimum Loss Control of Double-Star Synchronous Machines Under Open Phase Conditions," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1956-1965, May 2008.   Abstract Link    Full Text

Abstract: In this paper, a new method for filtering the torque pulsations is proposed for double-star permanent magnet synchronous machines under fault conditions. The machine is supplied by two independent electric sources via two voltage source inverters. The proposed method deals with the case where an open-circuit fault occurs. To reduce the torque pulsations, the usual solution consists in supplying only the healthy star winding. Here, we propose to supply not only the healthy winding, but also the two remaining phases of the other star winding by the healthy legs of the faulty inverter. The stator current waveforms can be easily determined to minimize the copper losses while reducing the torque pulsations. Simulation and experimental results confirm the efficiency of the proposed method.

55.5.10    R. Kianinezhad, B. Nahid-Mobarakeh, L. Baghli, F. Betin, G.-A. Capolino, "Modeling and Control of Six-Phase Symmetrical Induction Machine Under Fault Condition Due to Open Phases," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1966-1977, May 2008.   Abstract Link    Full Text

Abstract: This paper introduces a new fault-tolerant operation method for a symmetrical six-phase induction machine (6PIM) when one or several phases are lost. A general decoupled model of the induction machine with up to three open phases is given. This model illustrates the existence of a pulsating torque when phases are opened. Then, a new control method reducing the pulsating torque and the motor losses is proposed in order to improve the drive performances. The proposed method is compared to two other existing techniques. The simulation and experimental results obtained on a dedicated test-rig confirm the validity and the efficiency of the proposed method for a fault-tolerant symmetrical 6PIM drive.

55.5.11    N. Bianchi, S. Bolognani, M.D. Pre, "Impact of Stator Winding of a Five-Phase Permanent-Magnet Motor on Postfault Operations," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1978-1987, May 2008.   Abstract Link    Full Text

Abstract: The performance of a five-phase permanent-magnet (PM) motor is analyzed under postfault conditions. Proper current control strategies are adopted so as to guarantee safe drive operation after any fault occurrence. This paper covers three fault types: the open circuit condition of a single phase, the open circuit condition of two nonadjacent phases, and the open circuit condition of two adjacent phases. Two motors with two different windings (with double and single layers, respectively) are compared under each fault type. This paper aims to highlight the difference in the motor performance of motors adopting these two different windings. A further novelty of this paper is that the proper current control strategies are derived analytically, including not only the fundamental harmonic of the flux-density distribution but also the higher harmonics. It is shown that these harmonics cause high torque oscillations. Owing to this analytical approach, the strategy can be applied to a variety of PM motors. In addition, the postfault current waveforms remain sinusoidal, making the current control easier. For each fault type, the results of both simulations and experimental tests are included. A good match between analytical predictions and experimental tests validates the proposed current control strategies.

55.5.12    S. Dwari, L. Parsa, "An Optimal Control Technique for Multiphase PM Machines Under Open-Circuit Faults," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1988-1995, May 2008.   Abstract Link    Full Text

Abstract: In this paper, an optimal control technique for n-phase permanent-magnet (PM) machines under various open circuit faults is presented. Under the fault conditions, the currents in the healthy phases are controlled to compensate phase loss and to produce the required output torque. The proposed control technique ensures continuous operation of the machines while producing minimum torque ripples and minimum stator ohmic loss. The control technique is based on the instantaneous power balance theory. To set the summation of the phase currents equal to zero, a constraint is incorporated in the derivation of the control technique. A five-phase PM machine is considered to demonstrate the proposed open circuit fault-tolerant control strategy. Simulation and experimental results are provided for validation.

55.5.13    Libo Zheng, J.E. Fletcher, B.W. Williams, Xiangning He, "Dual-Plane Vector Control of a Five-Phase Induction Machine for an Improved Flux Pattern," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 1996-2005, May 2008.   Abstract Link    Full Text

Abstract: A technique to improve the flux pattern within a five-phase induction machine is presented. The technique is developed through dual-plane vector control, with synchronized fluxes. By vector space decomposition, an analytical model and vector control of the machine are accomplished in two orthogonal vector planes,d1-q1 and ds-qs . The magnitude and rotating speed of the associated fluxes (fundamental and third harmonic) can be independently controlled in each vector plane. Synchronization control locks the relative position between the two fluxes. The resultant air-gap flux density is fully controlled, preventing iron saturation. This feature is especially important in reshaping the flux and back EMF waveform of the machine. A quasi-trapezoidal air-gap flux density distribution is achieved for better iron utilization and higher torque density. It is confirmed that compared with sinusoidal fluxing, the quasi-trapezoidal flux pattern will not lead to an oversized power inverter when improving machine torque density. The basic understanding and control scheme can be extended to a multiphase induction machine with a phase number greater than five.

55.5.14    M.J. Duran, F. Salas, M.R. Arahal, "Bifurcation Analysis of Five-Phase Induction Motor Drives With Third Harmonic Injection," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2006-2014, May 2008.   Abstract Link    Full Text

Abstract: The interest in variable-speed multiphase induction- motor drives has substantially increased in recent years and novel proposals show good prospects for industrial implementation in high-power applications. The additional degrees of freedom existing in multiphase machines have allowed for new applications with high torque density by current harmonic injection in concentrated winding machines. This paper addresses, for the first time, the bifurcation analysis of a five-phase induction-motor drive when a third harmonic is injected for torque-enhancement purposes. The main focus of this paper is to present a mathematically based study of the nonlinear dynamics of the proposed drive with torque enhancement. The overall bifurcation analysis for both concentrated and distributed winding machines confirms that the harmonic injection provides not only torque enhancement but also more robust controllers. This further advantage offers improved performance of multiphase drives compared to their three-phase counterparts.

55.5.15    A. Boglietti, R. Bojoi, A. Cavagnino, A. Tenconi, "Efficiency Analysis of PWM Inverter Fed Three-Phase and Dual Three-Phase High Frequency Induction Machines for Low/Medium Power Applications," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2015-2023, May 2008.   Abstract Link    Full Text

Abstract: A performance analysis of three-phase and dual three-phase (DTP) induction pulsewidth modulation (PWM) inverter-fed motor drives is conducted in this paper. The focus is on the efficiency performance of high-frequency DTP machines compared to their three-phase counterparts in low/medium power applications. For this purpose, a DTP machine, having two sets of stator three-phase windings spatially shifted by 30 electrical degrees (asymmetrical six-phase winding configuration), was tested for both six-phase and three-phase winding configurations under the same magnetic conditions. Simulation and experimental results are presented to evaluate the efficiency performance of three-phase and dual-three induction motor drives employing PWM voltage source inverters.

55.5.16    C. Brandao Jacobina, I. Soares de Freitas, C. Ricarte da Silva, M. Beltrao de Rossiter Correa, E.R. Cabral da Silva, "Reduced Switch-Count Six-Phase AC Motor Drive Systems Without Input Reactor," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2024-2032, May 2008.   Abstract Link    Full Text

Abstract: In this paper, two reduced switch-count six-phase ac motor drives are investigated. The first configuration considered has six legs (configuration 6L), and the second one has five legs (configuration 5L) and uses the capacitor dc-link midpoint connection. Both configurations operate without input reactors and provide both bidirectional power flow and power-factor control. Both 60 and 30 six-phase induction-machine windings are employed. Operating principles and control strategies for the topologies are presented. The proposed configurations are compared with the full-bridge (nine legs) and the half-bridge (six legs) topologies, which use the capacitor dc-link midpoint connection. These drive systems are suitable for applications where the size of the system is a critical factor. Experimental and simulation results are presented.


Single-Phase Electronics
55.5.17    Byungcho Choi, Wonseok Lim, Seungwon Choi, Jian Sun, "Comparative Performance Evaluation of Current-Mode Control Schemes Adapted to Asymmetrically Driven Bridge-Type Pulsewidth Modulated DC-to-DC Converters," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2033-2042, May 2008.   Abstract Link    Full Text

Abstract: Three different current-mode control schemes, peak current-mode control, charge control, and average current-mode control, are investigated for application to asymmetrically driven bridge-type pulsewidth modulated dc-to-dc converters. The principles, implementation, and performance of the three control schemes are compared in an attempt to identify their respective merits and limitations. Design considerations for feedback compensations are also given for the three control schemes. The theoretical predictions of this paper are supported by both experimental results and computer simulations.

55.5.18    R.A. Mastromauro, M. Liserre, A. Dell'Aquila, "Study of the Effects of Inductor Nonlinear Behavior on the Performance of Current Controllers for Single-Phase PV Grid Converters," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2043-2052, May 2008.   Abstract Link    Full Text

Abstract: Resonant and repetitive controllers are well suited for single-phase grid-connected inverters due to their optimum tracking and harmonic rejection capability. In particular, in this paper, their application for single-phase photovoltaic systems is considered. The effects of nonlinear inductance on the performance of current controllers designed to track periodic signals and/or to compensate periodic disturbances are investigated. When the inductance has a nonlinear behavior, a distorted current waveform is produced. Two different nonlinearities have been considered: saturation for high currents and a light nonlinearity, which occurs in the first portion of the magnetization curve, for low currents. A current-dependent model of the nonlinear inductance has been developed. It is mathematically based on the Volterra-series expansion, and it allows us to prove how the harmonic compensation provided by resonant and repetitive controllers can also mitigate the effects of the inductance saturation. This result is the main contribution of this paper, and it is also substantiated with experimental evidence. Moreover, the repetitive controller is able to comply with the harmonic limits reported in IEEE 1547 and IEC 61727, even in very hard saturation conditions.

55.5.19    S. Saggini, P. Mattavelli, G. Garcea, M. Ghioni, "A Mixed-Signal Synchronous/Asynchronous Control for High-Frequency DC-DC Boost Converters," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2053-2060, May 2008.   Abstract Link    Full Text

Abstract: This paper investigates the application of a mixed-signal synchronous/asynchronous digital controller to DC-DC boost converters. The digital control synchronously generates current and voltage ramps by using two low-resolution digital-to-analog converters. The switch turn-on and turn-off are determined asynchronously by comparing the converter-state variables and the digitally generated current and voltage ramps. The control features high dynamic performance, frequency modulation during transients, small quantization effects, and low complexity. In order to evaluate the dynamic performance and compare the proposed solution with conventional analog peak-current-mode control, a small-signal model of the synchronous/asynchronous modulation is derived. Even if aimed to an integrated digital controller, experimental investigation has been performed by using discrete components, implementing the digital control in a field-programmable gate array by using a VHDL. The simulation and experimental results on 100-W DC-DC boost converter confirm the proposed analysis and show that the proposed solution enables a dynamic performance that is comparable with that of analog peak-current- mode control.


Multiphase Systems
55.5.20    S. Busquets-Monge, J.D. Ortega, J. Bordonau, J.A. Beristain, J. Rocabert, "Closed-Loop Control of a Three-Phase Neutral-Point-Clamped Inverter Using an Optimized Virtual-Vector-Based Pulsewidth Modulation," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2061-2071, May 2008.   Abstract Link    Full Text

Abstract: This paper presents a closed-loop control scheme for the three-level three-phase neutral-point-clamped dc-ac converter using the optimized nearest three virtual-space-vector pulsewidth modulation, which is a modulation that produces low output-voltage distortion with a significant reduction of the dc-link capacitance. A new specific loop modifying the modulating waveforms is proposed to rapidly control possible perturbations in the neutral-point voltage balance. An online estimation of the load displacement angle and load linear/nonlinear nature is introduced at no extra cost. The remaining part of the control is analogous to the control for a two-level converter with an appropriate interfacing to the selected modulation. The closed-loop control is designed for the case of a renewable-energy source connected to the ac mains, and its performance is analyzed through simulation and experiments.

55.5.21    Y.A.-R.I. Mohamed, E.F. El-Saadany, "A Control Scheme for PWM Voltage-Source Distributed-Generation Inverters for Fast Load-Voltage Regulation and Effective Mitigation of Unbalanced Voltage Disturbances," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2072-2084, May 2008.   Abstract Link    Full Text

Abstract: This paper presents a control scheme for grid-connected pulsewidth-modulated voltage-source inverters (VSIs) featuring fast load-voltage regulation and effective mitigation of unbalanced voltage disturbances. To ensure perfect regulation of the voltage at the point of common coupling (PCC) and provide means for rejecting fast and dynamic voltage disturbances, the frequency modes of the disturbances to be eliminated should be included in the stable closed-loop system. Toward this, a hybrid voltage controller combining a linear with variable-structure control element is proposed for an inverter-based distributed-generation interface to regulate the voltage at the PCC. The proposed voltage controller can embed a wide band of frequency modes through an equivalent internal model. Subsequently, a wide range of voltage perturbations, including capacitor-switching disturbances, can be rejected. To account for unbalanced voltage disturbances, a dual-sequence voltage controller is proposed. To provide accurate and robust tracking of the generated active and reactive current trajectories, a newly designed deadbeat current control algorithm is proposed. The controller is designed under the practical considerations of inherent plant delays, which are associated with the digital implementation of the control algorithm, and the uncertain nature of the current dynamics. Theoretical analysis and comparative evaluation tests are presented to demonstrate the effectiveness of the proposed control scheme.


Renewable Energy Systems
55.5.22    M.H. Bierhoff, F.W. Fuchs, "DC-Link Harmonics of Three-Phase Voltage-Source Converters Influenced by the Pulsewidth-Modulation Strategy—An Analysis," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2085-2092, May 2008.   Abstract Link    Full Text

Abstract: DC-link current harmonics are the predominant factor to be considered for dimensioning dc capacitors in three-phase pulsewidth-modulation (PWM) voltage-source converters. In this paper, an analysis of the dc-link current harmonics applying a double Fourier series is derived. The analytical results for the dc-link current spectra of continuous and discontinuous PWMs are presented and compared with measurement results taken from a converter test setup. A good match between theoretically expected and actually obtained experimental results can be stated. Moreover, characteristic differences between the investigated modulation strategies regarding their dc-link current spectra become evident.

55.5.23    M. Cirrincione, M. Pucci, G. Vitale, "A Single-Phase DG Generation Unit With Shunt Active Power Filter Capability by Adaptive Neural Filtering," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2093-2110, May 2008.   Abstract Link    Full Text

Abstract: This paper deals with a single-phase distributed generation (DG) system with active power filtering (APF) capability, devised for utility current harmonic compensation. The idea is to integrate the DG unit functions with shunt APF capabilities, because the DG is connected in parallel to the grid. With the proposed approach, control of the DG unit is performed by injecting into the grid a current with the same phase and frequency of the grid voltage and with an amplitude depending on the power available from renewable sources. On the other hand, load harmonic current compensation is performed by injecting into the alternating current system harmonic currents like those of the load but with an opposite phase, thus keeping the line current almost sinusoidal. Both detection of the grid voltage fundamental and computation of the load harmonic compensation current have been performed by two neural adaptive filters with the same structure, one in a configuration ldquonotchrdquo and the other in the complementary configuration ldquoband.rdquo The ldquonotchrdquo filter has been used to compute the compensation current by eliminating only the contribution of the fundamental of the load current, whereas the ldquobandrdquo configuration is able to extract the fundamental of the coupling point voltage. Furthermore, because the active power generation and the APF features require current control of components at different frequencies, respectively, a multiresonant current controller has been adopted. The methodology has been tested successfully both in numerical simulation and experimentally on a suitably devised test setup. The stability analysis of the proposed control approach has been performed in the discrete domain.


Robotics and Mechatronics
55.5.24    Chenglong Fu, Ken Chen, "Gait Synthesis and Sensory Control of Stair Climbing for a Humanoid Robot," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2111-2120, May 2008.   Abstract Link    Full Text

Abstract: Stable and robust walking in various environments is one of the most important abilities for a humanoid robot. This paper addresses walking pattern synthesis and sensory feedback control for humanoid stair climbing. The proposed stair-climbing gait is formulated to satisfy the environmental constraint, the kinematic constraint, and the stability constraint; the selection of the gait parameters is formulated as a constrained nonlinear optimization problem. The sensory feedback controller is phase dependent and consists of the torso attitude controller, zero moment point compensator, and impact reducer. The online learning scheme of the proposed feedback controller is based on a policy gradient reinforcement learning method, and the learned controller is robust against external disturbance. The effectiveness of our proposed method was confirmed by walking experiments on a 32-degree-of-freedom humanoid robot.

55.5.25    W.L. Xu, J.D. Torrance, B.Q. Chen, J. Potgieter, J.E. Bronlund, J.-S. Pap, "Kinematics and Experiments of a Life-Sized Masticatory Robot for Characterizing Food Texture," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2121-2132, May 2008.   Abstract Link    Full Text

Abstract: A life-sized masticatory robot, which is intended to chew foods in a human way while the food properties are evaluated, of a 6RSS parallel mechanism is discussed in this paper. A robotic mechanism is proposed, and its kinematic parameters are defined according to the biomechanical findings and measurements of the human masticatory system. For a given mandibular trajectory to be tracked, the closed-form solution to inverse kinematics of the robot is found for joint actuations, whereas differential kinematics is derived in Jacobian matrices. Major features of the robot, including the motion control system, are presented. Experimental results for free chewing, soft-food chewing, and hard-food chewing are given where the foods are simulated by foam and hard objects, and crank actuations and driving torques (an indication of muscular activities) required are compared for the chewing of different foods.


Drive Control
55.5.26    A.N. Alcaso, A.J. Marques Cardoso, "Remedial Operating Strategies for a 12-Pulse LCI Drive System," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2133-2139, May 2008.   Abstract Link    Full Text

Abstract: This paper reports on the study of the load-commutated inverter drive operating with an open-switch fault in the line-side converters. To improve this faulty operation, some strategies are presented in order to decrease the harmonic content of currents and the pulsating torque of the motor. To validate the proposed strategies, experimental results are presented.

55.5.27    Bo Yin, R. Oruganti, S.K. Panda, A.K.S. Bhat, "An Output-Power-Control Strategy for a Three-Phase PWM Rectifier Under Unbalanced Supply Conditions," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2140-2151, May 2008.   Abstract Link    Full Text

Abstract: Instantaneous power regulation is an effective way to improve the performance of a pulsewidth-modulation rectifier operating under unbalanced supply-voltage conditions. By properly setting current commands, this approach aims to achieve performance features that are normally achievable only under ideal balanced operating conditions. This paper proposes an instantaneous power-regulation strategy called output-power-control method, in which the current commands are determined so as to appropriately distribute the input power to maintain a constant dc output voltage and sinusoidal line currents. Although the power factor is not directly controlled, it is shown that the proposed scheme results in near unity vector power factor. The current commands are given by a set of simple linear equations in which the proposed control scheme can be easily implemented. Experimental results obtained with a 1-kW laboratory prototype demonstrate that the proposed scheme fulfils all the main objectives of a high-performance rectifier.

55.5.28    K. Natori, K. Ohnishi, "A Design Method of Communication Disturbance Observer for Time-Delay Compensation, Taking the Dynamic Property of Network Disturbance Into Account," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2152-2168, May 2008.   Abstract Link    Full Text

Abstract: This paper presents a design method of time-delayed control systems. Because of the tremendous spread of computer networks, control strategies for time-delayed control systems are needed for network-based control systems (NBCSs) and other network applications. Although model-based or predictive control methods (like a Smith predictor) are often used for time-delay compensation, the performance often deteriorates when the value of time delay is uncertain. In these circumstances, a novel time-delay-compensation method based on the concept of network disturbance (ND) and communication disturbance observer (CDOB) has been proposed. The method has the same effectiveness for time-delay compensation as that of the Smith predictor. Furthermore, because the method works without delay-time model, it can be flexibly applied to many kinds of time-delayed control systems. In this paper, a design method of CDOB, considering the dynamic property of ND, is proposed in the situation of constant time delay. The dynamic property of ND leads to two design conditions of CDOB. Those design conditions are derived considering relationships between poles of CDOB and ND dynamics. Then, the actual design procedure of CDOB based on derived design conditions is presented in two different delay cases. The stability of the designed control systems is clarified by stability analysis. The validity of the proposed design method is verified by experimental results. Finally, we present experimental results in the case of random delay as an example of practical application of the time-delay compensation method to actual NBCSs.


Signal Processing and Control
55.5.29    T.N. Chang, N. Ansari, "Passband Control of Lightly Damped Systems With Mode Separation," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2169-2176, May 2008.   Abstract Link    Full Text

Abstract: This paper deals with the regulation and stabilization of lightly damped systems under plant uncertainty. A controller consisting of a neural-network-based mode separator together with a modular passband tuning regulator is proposed. The mode separator generates the in-phase components of the plant utilized by the passband tuning regulator to maintain closed-loop stability and asymptotic regulation. This combined controller is robust and requires minimal plant information to operate. A synthesis procedure is outlined in this paper to summarize the design steps in a systematic manner. Finally, the application of the passband controller to the stabilization of a magnetic leadscrew is considered. Resonance is shown to be completely eliminated. The stabilization time of the transient response is also significantly reduced, confirming the feasibility of the controller.

55.5.30    M. Jager, S. Humbert, F.A. Hamprecht, "Sputter Tracking for the Automatic Monitoring of Industrial Laser-Welding Processes," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2177-2184, May 2008.   Abstract Link    Full Text

Abstract: The importance of laser welding in industry increases. Many welds have high-quality demands, and one possibility to satisfy the quality requirements is to monitor the welding process with high-speed cameras. Laser welding is a highly dynamic process; it is therefore challenging to distinguish between normal process fluctuations and abnormal error events in the recorded sequences. This paper investigates a novel classification method to automatically analyze the recorded welding sequences and robustly find the abnormal error events. To our knowledge, it is the first time that a framework to detect and track sputters in welding sequences is proposed and evaluated. To achieve a high usability of the classification algorithm, in the training phase, the user only needs to mark suspicious sequences but does not need to label individual frames within the sequences. The framework is tested on two challenging data sets from real welding processes. The results show that the material particles can be tracked accurately. On a sample data set, the new approach finds all erroneous welds with a small false-positive rate and outperforms previously developed methods.

55.5.31    M.A. Perez, J.R. Espinoza, L.A. Moran, M.A. Torres, E.A. Araya, "A Robust Phase-Locked Loop Algorithm to Synchronize Static-Power Converters With Polluted AC Systems," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2185-2192, May 2008.   Abstract Link    Full Text

Abstract: In this paper, a phase-locked loop algorithm appropriated for digital-signal-processor-based control implementations, where the operation of a static-power converter needs to be synchronized with an ac network, is presented. The proposed algorithm includes a multiplier, a filter, a feedback closed loop, and a numerically controlled oscillator stage. As a result, a discrete sine (and cosine) signal is generated in synchronism with the fundamental component of an external-reference (ER) signal. Moreover, the sampling period of the algorithm is adjusted at each sampling instant such that an integer number of sampling periods per period of the ER signal is ensured. This is the main feature, and it is achieved by using a discrete rectangular window filter and a discrete controller. The proposed algorithm code is simple, stable, and presents high noise rejection. A comprehensive theoretical justification and various rigorous experimental tests are included.


Diagnosis and Monitoring
55.5.32    A. Ordaz-Moreno, R. de Jesus Romero-Troncoso, J.A. Vite-Frias, J.R. Rivera-Gillen, A. Garcia-Perez, "Automatic Online Diagnosis Algorithm for Broken-Bar Detection on Induction Motors Based on Discrete Wavelet Transform for FPGA Implementation," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2193-2202, May 2008.   Abstract Link    Full Text

Abstract: Overall system performance on a production line is one of the major concerns in modern industry where induction motors are present and their condition monitoring is mandatory. Periodic offline monitoring of the motor condition is usually performed in the industry, consuming production time and increasing cost. Broken rotor bars are among the most common failures in induction motors. Reported research projects give a broken-rotor-bar-detection methodology based on personal-computer implementation that is performed offline and requires an expert technician interpretation which is not a cost-effective solution. The novelty of this paper is the development of an automatic online diagnosis algorithm for broken-rotor-bar detection, optimized for single low-cost field-programmable gate-array (FPGA) implementation, which guarantees the development of economical self-operated equipment. The proposed algorithm requires less computation load than the previously reported algorithms, and it is mainly based on the discrete-wavelet-transform application to the start-up current transient; a further single mean-square computation determines a weighting function that, according to its value, clearly points the motor condition as either healthy or damaged. In order to validate the proposed algorithm, several tests were performed, and an FPGA implementation was developed to show the algorithm feasibility for automatic online diagnosis.


Emerging Technology
55.5.33    M. Carpita, M. Marchesoni, M. Pellerin, D. Moser, "Multilevel Converter for Traction Applications: Small-Scale Prototype Tests Results," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2203-2212, May 2008.   Abstract Link    Full Text

Abstract: In ac-supplied traction systems (e.g., 15 kV, 16.7 Hz), the energy supplied by a conventional transformer results in large volume, high weight, and relatively low efficiency. In this paper, an ac-dc multilevel converter is presented that allows the use of a medium-frequency transformer in the input section of a traction drive. The proposed solution seems particularly well adapted to the different requirements (volume, weight, EMC, losses) of the electric traction domain. The system is studied from a theoretical point of view, starting from the basic module up to the entire converter structure. Simulation results and reduced-scale (10-kVA four-stage converter) experimental results are presented.

55.5.34    W. Eberle, Yan-Fei Liu, P.C. Sen, "A New Resonant Gate-Drive Circuit With Efficient Energy Recovery and Low Conduction Loss," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2213-2221, May 2008.   Abstract Link    Full Text

Abstract: In this paper, a new resonant gate-drive circuit is proposed to recover a portion of the power-MOSFET-gate energy that is typically dissipated in high-frequency converters. The proposed circuit consists of four control switches and a small resonant inductance. The current through the resonant inductance is discontinuous in order to minimize circulating-current conduction loss that is present in other methods. The proposed circuit also achieves quick turn-on and turn-off transition times to reduce switching and conduction losses in power MOSFETs. An analysis, a design procedure, and experimental results are presented for the proposed circuit. Experimental results demonstrate that the proposed driver can recover 51% of the gate energy at 5-V gate-drive voltage.


Letters to the Editor
55.5.35    Chong-Eun Kim, Gun-Woo Moon, "Input-Voltage Feedforward (IVFF) Circuit Minimizing Current Stress of Voltage-Doubler Rectified Asymmetrical Half-Bridge (VDRAHB) Converter," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2222-2224, May 2008.   Abstract Link    Full Text

Abstract: A new input-voltage feedforward (IVFF) circuit for a voltage-doubler rectified asymmetrical half-bridge (VDRAHB) converter is proposed in this letter. The proposed circuit regulates output voltage not by reducing duty ratio but by increasing switching frequency as input voltage increases. Therefore, by employing the proposed IVFF circuit into the VDRAHB converter, the peak currents of the overall components can be greatly reduced, and also, efficiency can be improved at high input voltages.

55.5.36    Yu-Kang Lo, Ting-Peng Lee, Kuan-Hung Wu, "Grid-Connected Photovoltaic System With Power Factor Correction," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2224-2227, May 2008.   Abstract Link    Full Text

Abstract: A combined grid-connection/power-factor-correction technique for a photovoltaic (PV) system is proposed in this letter. A maximum power point tracking dc/dc converter served as a charger for the battery bank. A bidirectional inverter is applied as a generator/discharger during daytime, supplying power to the load. The inverter can also be used as a charger to maintain the minimum required voltage level of the batteries when the PV power is insufficient. Experiments on a 1-kW PV system show satisfactory results of the power management and the unity power factor at the utility side.

55.5.37    "Call for papers industrial wireless sensors networks," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2228-2228, May 2008.   Abstract Link    Full Text

Abstract: Not Available

55.5.38    "Call for papers sliding mode control in industrial applications-part II," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2229-2229, May 2008.   Abstract Link    Full Text

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55.5.39    "Call for papers applications and control of doubly fed induction machines," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2230-2230, May 2008.   Abstract Link    Full Text

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55.5.40    "Over 1 million scientific documents easily within reach, from IEEE," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2231-2231, May 2008.   Abstract Link    Full Text

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55.5.41    "Why we joined ...," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. 2232-2232, May 2008.   Abstract Link    Full Text

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55.5.42    "IEEE Industrial Electronics Society Information," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. C3-C3, May 2008.   Abstract Link    Full Text

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55.5.43    "IEEE Transactions on Industrial Electronics information for authors," IEEE Trans. on Industrial Electronics, vol. 55, no. 5, pp. C4-C4, May 2008.   Abstract Link    Full Text

Abstract: Not Available