1. H. Abu-Rub, J. Guzinski, Z. Krzeminski, H.A. Toliyat, "Advanced control of induction motor based on load angle estimation," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 5- 14, Feb. 2004. Full Text Link Abstract : An advanced control system with load angle adjustment is introduced. The method is based on the action of a phase-locked loop, in which a position synchronization of two vectors to obtain a constant command angle between them is realized. In the system presented, the vectors are stator current and rotor flux. The load angle is kept constant by changing the position of stator current vector as a result of tuning its pulsation. Proportional-integral and fuzzy logic controllers are used to control the load angle. Because of using the load angle controller and simple relations for state variables, the proposed idea does not require exact speed measurement. The discussed control system is not sensitive to motor resistance variations. This idea is realized on a fixed-point digital signal processor and field-programmable gate arrays. Experimental results for the control system fed by a voltage-source inverter and controlled using a predictive current controller are presented.
2. Ching-Guo Chen, Tian-Hua Liu, Ming-Tsan Lin, Chih-An Tai, "Position control of a sensorless synchronous reluctance motor," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 15- 25, Feb. 2004. Full Text Link Abstract : This paper presents a novel position control for a sensorless synchronous reluctance drive system. By measuring the three-phase currents of the motor, a rotor position estimator is achieved. Then, a velocity estimator is derived from the estimated rotor position by using a state estimating technique. The estimated velocity tracks the real velocity well. Next, a robust position controller is designed to improve the transient and load disturbance responses. By using the proposed estimating techniques and control algorithm, a high-performance sensorless synchronous reluctance drive is obtained. A digital signal processor, TMS-320-C30, is used to execute the estimating and control algorithms. No hardware circuit or external signal is added as compared with the traditional drive system with an encoder or resolver. To evaluate the performance of the position control system, a moving table is connected with the drive system. The drive system can precisely control the moving table. Experimental results show that the proposed system has good performance. Several experimental results validate the theoretical analysis.
3. Z.-J. Yang, K. Miyazaki, S. Kanae, K. Wada, "Robust position control of a magnetic levitation system via dynamic surface control technique," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 26- 34, Feb. 2004. Full Text Link Abstract : This paper considers the position-tracking problem of a magnetic levitation system in the presence of modeling errors due to uncertainties of physical parameters. A robust nonlinear controller is designed to achieve excellent position-tracking performance. The recently developed dynamic surface control is modified and applied to the system under study, to over-come the problem of "explosion of terms" associated with the backstepping design procedure. Input-to-state stability of the control system is analyzed, and the advantages of the dynamic surface control technique over the conventional backstepping technique are verified through both theoretical and experimental studies.
4. Ya-Fu Peng, Rong-Jong Wai, Chih-Min Lin, "Implementation of LLCC-resonant driving circuit and adaptive CMAC neural network control for linear piezoelectric ceramic motor," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 35- 48, Feb. 2004. Full Text Link Abstract : In this paper, an adaptive cerebellar-model articulation computer (CMAC) neural network (NN) control system is developed for a linear piezoelectric ceramic motor (LPCM) that is driven by an LLCC-resonant inverter. The motor structure and LLCC-resonant driving circuit of an LPCM are introduced initially. The LLCC-resonant driving circuit is designed to operate at an optimal switching frequency such that the output voltage will not be influenced by the variation of quality factor. Since the dynamic characteristics and motor parameters of the LPCM are highly nonlinear and time varying, an adaptive CMAC NN control system is designed without mathematical dynamic model to control the position of the moving table of the LPCM drive system to achieve high-precision position control with robustness. In the proposed control scheme, the dynamic backpropagation algorithm is adopted to train the CMAC NN online. Moreover, to guarantee the convergence of output tracking error for periodic commands tracking, analytical methods based on a discrete-type Lyapunov function are utilized to determine the optimal learning-rate parameters of the CMAC NN. The effectiveness of the proposed driving circuit and control system is verified by experimental results in the presence of uncertainties, and the advantages of the proposed control system are indicated in comparison with a traditional integral-proportional position control system. Accurate tracking response and superior dynamic performance can be obtained due to the powerful online learning capability of the CMAC NN with optimal learning-rate parameters.
5. A. Bunte, S. Beineke, "High-performance speed measurement by suppression of systematic resolver and encoder errors," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 49- 53, Feb. 2004. Full Text Link Abstract : The subject of this paper is a method which suppresses systematic errors of resolvers and optical encoders with sinusoidal line signals. The proposed method does not require any additional hardware and the computational efforts are minimal. Since this method does not cause any time delay, the dynamic of the speed control is not affected. By means of this new scheme, dynamic and smooth running characteristics of drive systems are improved considerably.
Power Electronics
6. D.B. Costa, C.M.C. Duarte, "The ZVS-PWM active-clamping CUK converter," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 54- 60, Feb. 2004. Full Text Link Abstract : A CUK converter featuring clamping action, pulsewidth modulation, and soft-switching commutation is proposed to overcome the limitations of the conventional CUK converter. As the resonant circuits absorb almost all parasitic reactances of switches, including transistor output capacitances, this converter is suitable for high-frequency operation. Principle of operation, theoretical analysis, and simulation results are presented in this paper. Experimental results, taken from a laboratory prototype rated at 400 W, input voltage of 150 V, output voltage of 200 V, and operating at 100 kHz, are also presented. The efficiency obtained at full load of the power stage was 93%.
7. Jianguo Liu, P. Pillay, H. Douglas, "Wavelet modeling of motor drives applied to the calculation of motor terminal overvoltages," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 61- 66, Feb. 2004. Full Text Link Abstract : The wavelet is a powerful tool that has emerged for the calculation of power system transients. In this paper, a wavelet motor drive model is developed and applied to the overvoltage problem which occurs with high dv/dt inverters. This technique is fundamentally different from EMTP and Pspice, which are time-domain methods. Wavelet models of typical passive parameters are derived and then applied to the problem of motor terminal overvoltages, which occurs with long cable lengths. It is proved that the simulation results with wavelet modeling is faster in the solution of this complex, power system simulation problem. Additional insight is possible by examining the wavelet coefficients.
8. S. Tamai, S. Murakami, R. Uchida, H. Akagi, "Control and performance of a self-commutated GTO converter operating in parallel with line-commutated thyristor converters," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 67- 73, Feb. 2004. Full Text Link Abstract : Recently, static var generators (SVGs) or static synchronous compensators based on self-commutated converters have been put into practical use for the purpose of compensation for reactive power, power swings damping, and/or voltage control in power systems. The SVGs have also been applied to reduce voltage fluctuations appearing at high-speed train substations. When parallel resonance occurs between passive filters installed at a point of common coupling (PCC) and the power-system impedance existing upstream of the PCC, voltage/current harmonics are significantly amplified in the power system. This paper describes the control and performance for a self-commutated gate-turn-off (GTO) converter operating in parallel with conventional line-commutated thyristor converters. This hybrid power conversion system rated at more than dozens of MVA has an inductive load at the dc side. A bank of passive filters is connected not only for harmonic compensation of the line-commutated converters, but also as a constant leading reactive-power source. The GTO converter can control either leading or lagging reactive power so as to achieve unity power factor operation. In addition, it has the capability of damping out parallel resonance between the passive filters and the power-system impedance. This paper confirms the viability and effectiveness of the hybrid system by means of theory and computer simulation.
9. D.A. Bennett, R.H. Selfridge, J.N. Harb, D.T. Comer, "A control circuit for a microsensor hybrid power supply," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 74- 80, Feb. 2004. Full Text Link Abstract : This paper presents a simple low-power control circuit intended to manage the power within a remote autonomous microsystem hybrid power supply. A hybrid power supply has only recently been discussed in the literature as a microsystem power source solution. The power management circuitry, which is a key component within a hybrid power supply, has not been adequately explored. Although a variety of components could have been implemented, the control circuit in this paper was designed for a hybrid power supply that utilizes a Ni/Zn microbattery and silicon solar cell. The circuit also employs a shunt architecture powered only by the solar cell to minimize the overall energy consumption of the hybrid power supply. The control circuit consumes a maximum of 7 /spl mu/A and appropriately manages power even when the hybrid power supply is connected to a microsystem and is experiencing environmental variations. Details of the control circuit are discussed and simulations combined with experimental results demonstrate its performance.
10. Xiangning He, Yan Deng, B.W. Williams, S.J. Finney, Zhaoming Qian, "A simple energy recovery circuit for high-power inverters with complete turn-on and turn-off snubbers," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 81- 88, Feb. 2004. Full Text Link Abstract : This paper presents and analyzes an active energy recovery circuit for the inductive turn-on snubber and capacitive turn-off snubber used on high-power gate-turn-off thyristor inverters. The circuit performs as a simple switched-mode power supply and recovers the inductive and capacitive snubbers energy induced in power inverters back into the dc rail with the aid of an extra switch. The features and operation of the proposed circuit are given and supported by PSpice simulations and experimental results.
11. H. Bodur, A.F. Bakan, "An improved ZCT-PWM DC-DC converter for high-power and frequency applications," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 89- 95, Feb. 2004. Full Text Link Abstract : In this paper, an improved active resonant snubber cell that overcomes most of the drawbacks of the normal zero-current transition (ZCT) pulsewidth-modulation (PWM) dc-dc converter is proposed. This snubber cell is especially suitable for an insulated gate bipolar transistor (IGBT) PWM converter at high power and frequency levels. The converter with the proposed snubber cell can operate successfully with soft switching under light-load conditions and at considerably high frequencies. The operation principles, a detailed steady-state analysis, and a snubber design procedure of a ZCT-PWM buck converter implemented with the proposed snubber cell are presented. Theoretical analysis is verified with a prototype of a 5-kW and 50-kHz IGBT-PWM buck converter. Additionally, at 90% output power, the overall efficiency of the proposed soft switching converter increases to about 98% from the value of 91% in the hard-switching case.
12. A.M. Omar, N.A. Rahim, S. Mekhilef, "Three-phase synchronous PWM for flyback converter with power-factor correction using FPGA ASIC design," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 96- 106, Feb. 2004. Full Text Link Abstract : The design and development of a synchronous pulsewidth modulation (PWM) generator suitable for the three-phase flyback converter with transformer isolated and power-factor correction using a field-programmable gate array is proposed. The proposed three-phase synchronous PWM makes it possible for the converter to obtain the sinusoidal supply currents with a near-unity power factor. A high-frequency transformer is considered in the design to provide galvanic isolation and serves the dual role of inductor and transformer. Results are provided to demonstrate the effectiveness of the design.
13. M. Eltabach, A. Charara, I. Zein, "A comparison of external and internal methods of signal spectral analysis for broken rotor bars detection in induction motors," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 107- 121, Feb. 2004. Full Text Link Abstract : Like all mechanical devices, motors are subject to failures, which can sometimes lead to the shutting down of an entire industrial process. This paper looks at failure predictions in three-phase line-operated induction machines through spectral analysis or electric and electromagnetic signals. Fault characteristics frequencies generated in the estimated and the measured signal spectrum, as a result of mechanical abnormalities such as broken rotor bars, are analyzed. Spectral analyses of simple stator current, of the current's Park vector modulus, and or total and partial instantaneous electric powers are considered as external diagnosis. Internal methods of diagnosis are usually based on a mathematical model of the motor. This requires knowledge of the motor's electrical parameters, which are affected by a number of physical phenomena such as temperature variations, skin effects, core losses, and saturation. As internal diagnosis, we examine different approaches to the spectral analysis of electromagnetic torque computed by stator and rotor flux estimation. To this end, the open loop method, the Luenberger observer and the Kalman filter are employed. Finally, experimental results enable us to draw up a table of comparison of internal and external methods in the detection of rotor imperfections, using two criteria under different load levels.
14. C. Branas, F.J. Azcondo, S. Bracho, "Study of output power variation due to component tolerances in LC/sub s/C/sub p/ resonant inverters applied to HPS lamp control," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 122- 131, Feb. 2004. Full Text Link Abstract : The aim of this paper is to incorporate the analysis of component tolerance in the design criteria of resonant inverters applied to the control of high-pressure sodium (HPS) lamps. This method may also be considered for metal halide (MH) lamps. The design accepts a large load variation without exceeding the lamp power limits given by the standard. The analysis is focused on the selection of the most suitable value of the resonant network in order to achieve a good repeatability of the circuit performance. The study is based on the analysis of the lamp power sensitivity regarding the lamp aging and the tolerance of the circuit components. The proposed design is validated with experimental results and a statistical study by the Monte Carlo method.
15. G.-M. Lee, Dong-Choon Lee, Jul-Ki Seok, "Control of series active power filters compensating for source voltage unbalance and current harmonics," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 132- 139, Feb. 2004. Full Text Link Abstract : In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics in series-type active power filter systems combined with shunt passive filters is proposed, which focuses on reducing the delay time effect required to generate the reference voltage. Using digital all-pass filters, the positive voltage sequence component out of the unbalanced source voltage is derived. The all-pass filter can give a desired phase shift and no magnitude reduction, unlike conventional low-or high-pass filters. Based on this positive-sequence component, the source phase angle and the reference voltage for compensation are derived. This method is easier to implement and to tune controller gains. In order to reduce the delay time effect in the voltage control loop, the reference voltage is predicted a sampling period ahead. The validity of the proposed control scheme has been verified by experimental results.
16. Byungcho Choi, Jaehyun Nho, Honnyong Cha, Taeyoung Ahn, Seungwon Choi, "Design and implementation of low-profile contactless battery charger using planar printed circuit board windings as energy transfer device," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 140- 147, Feb. 2004. Full Text Link Abstract : This paper paper presents the practical details involved in the design and implementation of a contactless battery charger that employs a pair of neighboring printed circuit board (PCB) windings as a contactless energy transfer device. A prototype contactless battery charger developed for application with cellular phones is used as an example to address the design considerations for the PCB windings and energy transfer circuit, plus demonstrates the performance of the contactless charger adapted to a practical application system.
17. Chwei-Sen Wang, G.A. Covic, O.H. Stielau, "Power transfer capability and bifurcation phenomena of loosely coupled inductive power transfer systems," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 148- 157, Feb. 2004. Full Text Link Abstract : Loosely coupled inductive power transfer (LCIPT) systems are designed to deliver power efficiently from a stationary primary source to one or more movable secondary loads over relatively large air gaps via magnetic coupling. In this paper, a general approach is presented to identify the power transfer capability and bifurcation phenomena (multiple operating modes) for such systems. This is achieved using a high order mathematical model consisting of both primary and secondary resonant circuits. The primary compensation is deliberately designed to make the primary zero phase angle frequency equal the secondary resonant frequency to achieve maximum power with minimum VA rating of the supply. A contactless electric vehicle battery charger was used to validate the theory by comparing the measured and calculated operational frequency and power transfer. For bifurcation-free operation, the power transfer capability and controllability are assured by following the proposed bifurcation criteria. Where controllable operation within the bifurcation region is achievable, a significant increase in power is possible.
18. L. Helle, K.B. Larsen, A.H. Jorgensen, S. Munk-Nielsen, F. Blaabjerg, "Evaluation of modulation schemes for three-phase to three-phase matrix converters," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 158- 171, Feb. 2004. Full Text Link Abstract : This paper presents a method for evaluating different modulation schemes employed with three-phase to three-phase matrix converters. The evaluation method addresses three important modulator characteristics: the output waveform quality, the input waveform quality and the switching losses associated with the modulation schemes. The method is used to evaluate four different modulation strategies, all based on the direct space-vector modulation approach. Further, regarding the switching losses, the paper proposes a new space-vector approach by which the switching losses can be reduced by 15%-35%, depending on the output load angle. This new modulation approach is applicable whenever the output voltage reference is below half the input voltage and the output voltage quality is then superior to that of the conventional space vector modulation scheme. The functionality of the new modulation scheme is validated by both simulations and experimental results and compared to waveforms obtained by using exiting space vector modulation schemes. The output voltage of the proposed scheme turns out to be comparable to the best of the conventional schemes while the input current is more distorted.
Emerging Technology
19. F.H.F. Leung, H.K. Lam, S.H. Ling, P.K.S. Tam, "Optimal and stable fuzzy controllers for nonlinear systems based on an improved genetic algorithm," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 172- 182, Feb. 2004. Full Text Link Abstract : This paper addresses the optimization and stabilization problems of nonlinear systems subject to parameter uncertainties. The methodology is based on a fuzzy logic approach and an improved genetic algorithm (GA). The TSK fuzzy plant model is employed to describe the dynamics of the uncertain nonlinear plant. A fuzzy controller is then obtained to close the feedback loop. The stability conditions are derived. The feedback gains of the fuzzy controller and the solution for meeting the stability conditions are determined using the improved GA. In order to obtain the optimal fuzzy controller, the membership functions are further tuned by minimizing a defined fitness function using the improved GA. An application example on stabilizing a two-link robot arm will be given.
20. S. Wu, T.W.S. Chow, "Induction machine fault detection using SOM-based RBF neural networks," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 183- 194, Feb. 2004. Full Text Link Abstract : A radial-basis-function (RBF) neural-network-based fault detection system is developed for performing induction machine fault detection and analysis. Four feature vectors are extracted from power spectra of machine vibration signals. The extracted features are inputs of an RBF-type neural network for fault identification and classification. The optimal network architecture of the RBF network is determined automatically by our proposed cell-splitting grid algorithm. This facilitates the conventional laborious trial-and-error procedure in establishing an optimal architecture. In this paper, the proposed RBF machine fault diagnostic system has been intensively tested with unbalanced electrical faults and mechanical faults operating at different rotating speeds. The proposed system is not only able to detect electrical and mechanical faults, but the system is also able to estimate the extent of faults.
Robotics And Vision
21. W.L. Xu, S. Yue, "Pre-posed configuration of flexible redundant robot manipulators for impact vibration alleviating," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 195- 200, Feb. 2004. Full Text Link Abstract : In this paper, kinematics redundancy of a flexible redundant manipulator (FRM) is employed to alleviate the impact vibration resulting from objects grasping. A vibration-alleviating measure (VAM) of the FRM, and a vibration-alleviating ellipsoid (VAE) with respect to the measure are defined. A method to determine the pre-posed configuration of an FRM is presented based on the defined VAM and VAE. A finite-element model is used to describe the FRM's dynamics incorporating the grasped object. Simulation conducted on a planar FRM shows that the FRM experiences relatively less impact vibration at the pre-posed configuration determined by using the presented method.
22. Rong-Jong Wai, Meng-Chang Lee, "Intelligent optimal control of single-link flexible robot arm," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 201- 220, Feb. 2004. Full Text Link Abstract : This paper addresses the design and properties of an intelligent optimal control for a nonlinear flexible robot arm that is driven by a permanent-magnet synchronous servo motor. First, the dynamic model of a flexible robot arm system with a tip mass is introduced. When the tip mass of the flexible robot arm is a rigid body, not only bending vibration but also torsional vibration are occurred. In this paper, the vibration states of the nonlinear system are assumed to he unmeasurable, i.e., only the actuator position can be acquired to feed into a suitable control system for stabilizing the vibration states indirectly. Then, an intelligent optimal control system is proposed to control the motor-mechanism coupling system for periodic motion. In the intelligent optimal control system a fuzzy neural network controller is used to learn a nonlinear function in the optimal control law, and a robust controller is designed to compensate the approximation error. Moreover, a simple adaptive algorithm is proposed to adjust the uncertain bound in the robust controller avoiding the chattering phenomena. The control laws of the intelligent optimal control system are derived in the sense of optimal control technique and Lyapunov stability analysis, so that system-tracking stability can be guaranteed in the closed-loop system. In addition, numerical simulation and experimental results are given to verify the effectiveness of the proposed control scheme.
23. S. Katsura, K. Ohnishi, "Human cooperative wheelchair for haptic interaction based on dual compliance control," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 221- 228, Feb. 2004. Full Text Link Abstract : A human and a robot will carry out a task which is not attainable by themselves. In particular, a human recognizes environment and plans his trajectory without collision with obstacles. On the other hand, a robot generates a controlled force more than a human. In this paper, the best combination of human ability and robot capacity is considered. Based on force commands from a human, a robot supports it A reaction torque observer is implemented in a robot to observe an environmental disturbance. Environmental disturbance is classified into translational and rotational direction modes. As a result, adaptive force control in each mode is attained. Dual compliance control is applied to a wheelchair. A wheelchair that has the abilities of power-assist and relaxation of contact force is developed in this paper. As a result, operationality and stability are improved. The numerical and experimental results show the viability of the proposed method.
24. K. Morioka, Joo-Ho Lee, H. Hashimoto, "Human-following mobile robot in a distributed intelligent sensor network," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 229- 237, Feb. 2004. Full Text Link Abstract : The robots that will be needed in the near future are human-friendly robots that are able to coexist with humans and support humans effectively. To realize this, humans and robots need to be in close proximity to each other as much as possible. Moreover, it is necessary for their interactions to occur naturally. It is desirable for a robot to carry out human following, as one of the human-affinitive movements. The human-following robot requires several techniques: the recognition of the target human, the recognition of the environment around the robot, and the control strategy for following a human stably. In this research, an intelligent environment is used in order to achieve these goals. An intelligent environment is a space in which many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents providing humans with services. A mobile robot is controlled to follow a walking human using distributed intelligent sensors as stably and precisely as possible. The control law based on the virtual spring model is proposed to mitigate the difference of movement between the human and the mobile robot. The proposed control law is applied to the intelligent environment and its performance is verified by the computer simulation and the experiment.
Letters To The Editor
25. P. Sooraksa, G. Chen, "On comparison of hybrid fuzzy PI plus conventional D controller versus fuzzy PI+D controller," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 238- 239, Feb. 2004. Full Text Link Abstract : This letter points out that a comparison given in an earlier paper by Er and Sun (ibid. vol. 48, pp. 1109-1117, 2001) is incorrect. The fuzzy PI+D controller designed by Misir et al. ( Fuzzy Sets Syst. vol. 79, pp. 297-314, 1996) is overall better than the hybrid fuzzy PI plus conventional D controller designed by Er and Sun.
26. P.W. Wheeler, J. Clare, L. Empringham, "Enhancement of matrix converter output waveform quality using minimized commutation times," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 240- 244, Feb. 2004. Full Text Link Abstract : This letter introduces a new concept in current commutation for matrix converters that minimizes the commutation time and, hence, enhances the output waveform quality. This commutation technique overcomes all the waveform quality problems associated with dead times in inverter-based circuits without the need for compensation. Practical results from a 10-kVA matrix converter are presented.
27. C.M. Saaj, B. Bandyopadhyay, H. Unbehauen, "A minor correction to "A new algorithm for discrete-time sliding mode control using fast output sampling feedback"," IEEE Trans. on Industrial Electronics, vol. 51, no. 1, pp. 244- 247, Feb. 2004. Full Text Link Abstract : The purpose of this letter is to show that the recently proposed fast output sampling sliding-mode control method in an earlier paper by the authors needs a small correction in the expression for the control law. The results or the corrected algorithm is illustrated by the same example considered in the earlier paper.
IEEE Transactions on Industrial Electronics
