IEEE Transactions on Industrial Electronics 

Volume 56,  Number 6, June 2009           Access to the journal on IEEE XPLORE     IE Transactions Home Page



                Special Section on Predictive Control In Power Electronics and Drives-Part II

56.6.1    M. P. Kazmierkowski, R. M. Kennel, J. Rodriguez Perez, "Guest Editorial," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1823-1825, June 2009.   Abstract Link    Full Text

Abstract: Not Available


Special Section Papers
56.6.2    S. Kouro, P. Cortes, R. Vargas, U. Ammann, J. Rodriguez, "Model Predictive Control—A Simple and Powerful Method to Control Power Converters," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1826-1838, June 2009.   Abstract Link    Full Text

Abstract: This paper presents a detailed description of Finite Control Set Model Predictive Control (FCS-MPC) applied to power converters. Several key aspects related to this methodology are, in depth, presented and compared with traditional power converter control techniques, such as linear controllers with pulsewidth-modulation-based methods. The basic concepts, operating principles, control diagrams, and results are used to provide a comparison between the different control strategies. The analysis is performed on a traditional three-phase voltage source inverter, used as a simple and comprehensive reference frame. However, additional topologies and power systems are addressed to highlight differences, potentialities, and challenges of FCS-MPC. Among the conclusions are the feasibility and great potential of FCS-MPC due to present-day signal-processing capabilities, particularly for power systems with a reduced number of switching states and more complex operating principles, such as matrix converters. In addition, the possibility to address different or additional control objectives easily in a single cost function enables a simple, flexible, and improved performance controller for power-conversion systems.

56.6.3    P. Lezana, R. Aguilera, D. E. Quevedo, "Model Predictive Control of an Asymmetric Flying Capacitor Converter," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1839-1846, June 2009.   Abstract Link    Full Text

Abstract: Multilevel converters and, in particular, flying capacitor (FC) converters are an attractive alternative for medium-voltage applications. FC converters do not need complex transformers to obtain the dc-link voltage and also present good robustness properties, when operating under internal fault conditions. Unfortunately, with standard modulation strategies, to increase the number of output voltage levels of FC converters, it is necessary to increase the number of cells and, hence, the number of capacitors and switches. In this paper, we develop a finite-state model predictive control strategy for FC converters. Our method controls output currents and voltages and also the FC voltage ratios. This allows one to increase the number of output voltage levels, even at high power factor load conditions and without having to increase the number of capacitors and switches. Experimental results illustrate that the proposed algorithm is capable of achieving good performance, despite possible parameter mismatch.

56.6.4    P. Correa, J. Rodriguez, M. Rivera, J. R. Espinoza, J. W. Kolar, "Predictive Control of an Indirect Matrix Converter," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1847-1853, June 2009.   Abstract Link    Full Text

Abstract: This paper presents the implementation of a predictive control scheme for an indirect matrix converter. The control scheme selects the switching state that minimizes the reactive power and the error in the output currents according to their reference values. This is accomplished by using a prediction horizon of one sample time and a very intuitive control law. Experimental results with a 6.8-kVA indirect matrix converter prototype are provided in order to validate the proposed control scheme. The converter uses standard digital signal processor operating at a sampling frequency of 20 $muhbox{s}$. It is shown that the idea of controlling this converter topology with a predictive approach can be implemented simply and input currents with unity power factor and a total harmonic distortion lower than 5% can be obtained.

56.6.5    Y.-S. Lai, C.-A. Yeh, "Predictive Digital-Controlled Converter With Peak Current-Mode Control and Leading-Edge Modulation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1854-1863, June 2009.   Abstract Link    Full Text

Abstract: The main theme of this paper is to present the digital controller design of a power converter with predictive peak current-mode (PCM) control and leading-edge modulation. The advantages of the control and modulation technique include the reduction of the sampling frequency of the A/D converter, no need of slope compensation, and the provision of a fast dynamic current response. The discrete-time model of the converter is presented as the fundamental to digital controller design and followed by the digital controller design. Moreover, the effect of predictive PCM control with leading edge modulation on limit cycle is analyzed. It is known that the limit cycle can be effectively suppressed as the converter has a predictive PCM control and leading edge modulation. Experimental results will be included to support fully the theoretical analysis.

56.6.6    A. G. Beccuti, S. Mariethoz, S. Cliquennois, S. Wang, M. Morari, "Explicit Model Predictive Control of DC–DC Switched-Mode Power Supplies With Extended Kalman Filtering," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1864-1874, June 2009.   Abstract Link    Full Text

Abstract: This paper presents a sensorless explicit model predictive control scheme for the dc–dc boost converter. No direct inductor current measurement is needed as the coil current is derived either via a static approximation or, for improved accuracy, through an extended Kalman filter. The estimate is used in the chosen optimal control problem formulation which yields the optimal input by intrinsically accounting for duty cycle and current constraints. The optimization problem is explicitly presolved offline so that the online effort is reduced to a simple search in the resulting lookup table. No online optimization is required, greatly facilitating physical implementation and allowing for experimental validation on an integrated dc–dc converter through a fixed-point DSP.

56.6.7    P. Cortes, G. Ortiz, J. I. Yuz, J. Rodriguez, S. Vazquez, L. G. Franquelo, "Model Predictive Control of an Inverter With Output $LC$ Filter for UPS Applications," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1875-1883, June 2009.   Abstract Link    Full Text

Abstract: The use of an inverter with an output $LC$ filter allows for generation of output sinusoidal voltages with low harmonic distortion, suitable for uninterruptible power supply systems. However, the controller design becomes more difficult. This paper presents a new and simple control scheme using predictive control for a two-level converter. The controller uses the model of the system to predict, on each sampling interval, the behavior of the output voltage for each possible switching state. Then, a cost function is used as a criterion for selecting the switching state that will be applied during the next sampling interval. In addition, an observer is used for load-current estimation, enhancing the behavior of the proposed controller without increasing the number of current sensors. Experimental results under linear and nonlinear load conditions, with a 5.5-kW prototype, are presented, verifying the feasibility and good performance of the proposed control scheme.

56.6.8    K. Drobnic, M. Nemec, D. Nedeljkovic, V. Ambrozic, "Predictive Direct Control Applied to AC Drives and Active Power Filter," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1884-1893, June 2009.   Abstract Link    Full Text

Abstract: This paper presents different applications of a method called direct control. The previously developed approach has been redefined into a generalized form. The method relies on the prediction of either current or flux in discrete-time intervals and, consequently, selects the inverter voltage vector that produces the fastest possible transient. Depending on the task, two possible variants have been developed, offering a compromise between ripple in the controlled variable and switching frequency. A special effort has been made to overcome problems due to various delays (processing time, acquisition, gate driver delay, etc.) in the prediction routine, thus achieving maximum performance. The approach has been upgraded for application in ac drives, which allows additional torque control. The functional versatility of the approach has been demonstrated on different applications of power electronics (active power filter, induction machine, surface-mounted permanent-magnet synchronous machine). All applications have been tested on different laboratory models and have confirmed the validity of the approach.

56.6.9    T. Geyer, G. Papafotiou, M. Morari, "Model Predictive Direct Torque Control—Part I: Concept, Algorithm, and Analysis," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1894-1905, June 2009.   Abstract Link    Full Text

Abstract: This paper focuses on direct torque control (DTC) for three-phase ac electric drives. A novel model predictive control scheme is proposed that keeps the motor torque, the stator flux, and (if present) the inverter's neutral point potential within given hysteresis bounds while minimizing the switching frequency of the inverter. Based on an internal model of the drive, the controller predicts several future switch transitions, extrapolates the output trajectories, and chooses the sequence of inverter switch positions (voltage vectors) that minimizes the switching frequency. The advantages of the proposed controller are twofold. First, as underlined by the experimental results in the second part of this paper, it yields a superior performance with respect to the industrial state of the art. Specifically, the switching frequency is reduced by up to 50% while the torque and flux are kept more accurately within their bounds. Moreover, the fast dynamic torque response is inherited from standard DTC. Second, the scheme is applicable to a large class of (three-phase) ac electric machines driven by inverters.

56.6.10    G. Papafotiou, J. Kley, K. G. Papadopoulos, P. Bohren, M. Morari, "Model Predictive Direct Torque Control—Part II: Implementation and Experimental Evaluation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1906-1915, June 2009.   Abstract Link    Full Text

Abstract: This paper describes the implementation of the model predictive direct torque control (MPDTC) algorithm for the control of three-phase induction motor drives comprising a three-level dc-link inverter. The MPDTC scheme is designed to keep the motor torque and stator flux and the inverter's neutral point potential within given hysteresis bounds while reducing the average switching frequency of the inverter, in comparison with the standard direct torque control (DTC) method. The algorithm is embedded in the control software environment of ABB's ACS6000 medium-voltage drive, and experimental results are provided which verify the advantageous features of MPDTC in terms of average inverter switching frequency reduction. More specifically, compared to standard DTC, the proposed MPDTC scheme achieves an average (over the whole operating range) reduction of the inverter switching frequency of 16.5%, but for specific operating conditions the reduction is as much as 37.4%.

56.6.11    H. Miranda, P. Cortes, J. I. Yuz, J. Rodriguez, "Predictive Torque Control of Induction Machines Based on State-Space Models," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1916-1924, June 2009.   Abstract Link    Full Text

Abstract: In this paper, we present a predictive control algorithm that uses a state-space model. Based on classical control theory, an exact discrete-time model of an induction machine with time-varying components is developed improving the accuracy of state prediction. A torque and stator flux magnitude control algorithm evaluates a cost function for each switching state available in a two-level inverter. The voltage vector with the lowest torque and stator flux magnitude errors is selected to be applied in the next sampling interval. A high degree of flexibility is obtained with the proposed control technique due to the online optimization algorithm, where system nonlinearities and restrictions can be included. Experimental results for a 4-kW induction machine are presented to validate the proposed state-space model and control algorithm.

56.6.12    S. Bolognani, L. Peretti, M. Zigliotto, "Design and Implementation of Model Predictive Control for Electrical Motor Drives," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1925-1936, June 2009.   Abstract Link    Full Text

Abstract: This paper deals with a model predictive control (MPC) algorithm applied to electrical drives. The main contribution is a comprehensive and detailed description of the controller design process that points out the most critical aspects and also gives some practical hints for implementation. As an example, the MPC is developed for a permanent-magnet synchronous motor drive. Speed and current controllers are combined together, including all of the state variables of the system, instead of keeping the conventional cascade structure. In this way, the controller enforces both the current and the voltage limits. Both simulation and experimental results point out the validity of the design procedure and the potentials of the MPC in the electrical drive field.

56.6.13    F. Barrero, M. R. Arahal, R. Gregor, S. Toral, M. J. Duran, "A Proof of Concept Study of Predictive Current Control for VSI-Driven Asymmetrical Dual Three-Phase AC Machines," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1937-1954, June 2009.   Abstract Link    Full Text

Abstract: Multiphase (more than three phases) drives possess interesting advantages over conventional three-phase drives. Over the last years, various topics related to the extension of the classical control schemes to these specifics drives have been covered in depth in literature, such as vector control of a six-phase induction machine with two sets of three-phase stator windings spatially shifted by 30 electrical degrees (also called asymmetrical dual three-phase ac machine). In this paper, a model-based predictive control (MBPC) for the current regulation of asymmetrical dual three-phase ac machines is analyzed. MBPC overcomes the difficulties of multiphase current control, avoiding complex controllers and modulation techniques, but at the expense of an increased computational cost. Simulation results are provided to examine the potential of the control method. The influence of the number of voltage vectors considered to evaluate the predictive model is studied, and different cost functions are analyzed. The computation time needed for the implementation of the control method is discussed to prove its real-time feasibility. Finally, experimental results are given to illustrate the capability of the control method.

56.6.14    R. Cao, K.-S. Low, "A Repetitive Model Predictive Control Approach for Precision Tracking of a Linear Motion System," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1955-1962, June 2009.   Abstract Link    Full Text

Abstract: In this paper, a new model predictive control (MPC) approach suitable for high precision linear motion drive operating with repetitive tracking tasks is presented. For the proposed predictive controller, the feedforward controller of the conventional MPC has been modified to provide zero-phase learning property. This is achieved by augmenting the reference trajectory with a phase-compensated term that is updated with the historical tracking error. The proposed approach attempts to combine the merits of both the conventional MPC and repetitive control schemes. Experimental results have demonstrated that the system effectively reduces the tracking error from the periodic disturbance caused by the friction. Its performance under varying reference conditions and different loadings shows that the system is robust.

56.6.15    M. Cychowski, K. Szabat, T. Orlowska-Kowalska, "Constrained Model Predictive Control of the Drive System With Mechanical Elasticity," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1963-1973, June 2009.   Abstract Link    Full Text

Abstract: In this paper, the application of model predictive control (MPC) for high-performance speed control and torsional vibration suppression in the drive system with flexible coupling is demonstrated. The control methodology presented in this paper relies on incorporating the drive's safety and physical limitations directly into the control problem formulation so that future constraint violations are anticipated and prevented. In order to reduce the computational complexity, the standard MPC controller is replaced by its explicit form. The resulting explicit controller achieves the same level of performance as the conventional MPC, but requires only a fraction of the real-time computational machinery, thus leading to fast and reliable implementation. The simulation results are confirmed by laboratory experiments.


Multiphase Systems
56.6.16    F. Barrero, M. R. Arahal, R. Gregor, S. Toral, M. J. Duran, "One-Step Modulation Predictive Current Control Method for the Asymmetrical Dual Three-Phase Induction Machine," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1974-1983, June 2009.   Abstract Link    Full Text

Abstract: Multiphase (more than three phases) drives exhibit interesting advantages over conventional three-phase drives. Over the last years, topics related to the extension of control schemes to these specific drives have been covered in depth in the literature. Direct torque control and predictive current control are normally used in conventional ac drives when fast electrical dynamic performance is required. In this paper, a one-step modulation predictive current control technique is proposed for asymmetrical dual three-phase ac drives. Based on the use of a predictive model including the motor and the inverter, the control algorithm determines the switching state which minimizes errors between predicted and reference state variables. The period of application of the selected switching state is then obtained, resulting in a submodulation method. The proposed predictive current control algorithm uses a prediction horizon of one sampling period; however, two switching states are applied during the sampling period. The switching states are the selected optimum active vector and a null voltage combination. Simulation and experimental results are provided to examine the features of the control method. Performances, advantages, and limitations are also discussed.

56.6.17    A. Bouafia, F. Krim, J.-P. Gaubert, "Fuzzy-Logic-Based Switching State Selection for Direct Power Control of Three-Phase PWM Rectifier," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1984-1992, June 2009.   Abstract Link    Full Text

Abstract: This paper proposes a novel and simple direct power control (DPC) scheme of a three-phase pulsewidth-modulated rectifier without the use of a predefined switching table. The converter switching state selection is based on fuzzy logic rules, using the instantaneous active and reactive power tracking errors as fuzzy logic variables. The basic idea of fuzzy rules synthesis is based on the knowledge of the instantaneous variation of active and reactive power. According to the input fuzzy variables and in a specific moment, the best switching state of the converter is chosen to restrict the instantaneous active and reactive power tracking errors simultaneously, for maintaining the dc-bus voltage close to the reference value and guarantying the unity-power-factor operation. The main advantages of the proposed DPC scheme, compared to the classical one, are that it is not necessary to use hysteresis comparators, and smooth control of active and reactive power is obtained during all sectors. Finally, the developed DPC was tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance, and verify the validity of the proposed DPC scheme which is much better than the classical DPC.

56.6.18    J. C. Moreno, J. M. Espi Huerta, R. G. Gil, S. A. Gonzalez, "A Robust Predictive Current Control for Three-Phase Grid-Connected Inverters," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 1993-2004, June 2009.   Abstract Link    Full Text

Abstract: This paper presents a new predictive control algorithm for grid-connected current-controlled inverters. The control combines a two-sample deadbeat control law with a Luenberger observer to estimate the future value of the grid currents. The resulting control offers robustness against the computational delay inherent in the digital implementation and considerably enhances the gain and phase margins of the previous predictive controls while maintaining the high-speed response typical of the deadbeat controllers.

56.6.19    S. G. Song, F. S. Kang, S.-J. Park, "Cascaded Multilevel Inverter Employing Three-Phase Transformers and Single DC Input," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2005-2014, June 2009.   Abstract Link    Full Text

Abstract: This paper proposes an isolated cascaded multilevel inverter employing low-frequency three-phase transformers and a single dc input power source. The proposed circuit configuration can reduce a number of transformers compared with traditional three-phase multilevel inverters using single-phase transformers. It controls switching phase angles to obtain an optimal switching pattern identified with the fundamental frequency of the output voltage. Owing to this control strategy, harmonic components of the output voltage and switching losses can be diminished considerably. To verify the performance of the proposed approach, we implemented computer-aided simulations and experiments using a prototype.

56.6.20    R. S. Herrera, P. Salmeron, "Instantaneous Reactive Power Theory: A Reference in the Nonlinear Loads Compensation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2015-2022, June 2009.   Abstract Link    Full Text

Abstract: The instantaneous reactive power theory was published 25 years ago, in an IEEE Transactions. Since then, it has been the most used in nonlinear load compensation with active power filters. Its application allows constant source power to be obtained after compensation in a simple way. Moreover, some researches have showed up some limitations of the theory, i.e., it goes optimally with source voltage balanced and sinusoidal, but not so good with source voltage unbalanced and/or nonsinusoidal, since the source current obtained is not balanced and sinusoidal. This paper presents a new compensation strategy in phase coordinates, equivalent to the original theory's one. Its simplicity, due to the nonnecessity of coordinate mathematical transformation, makes easier the modifications necessary to obtain alternative compensation objectives. In this way, this paper presents those modifications and derives compensation strategies that obtain alternative compensation objectives: unity power factor or balanced and sinusoidal source current. Finally, compensation strategies are applied to a practical power system, and the results are presented.

56.6.21    Z. Zhang, Y. Yan, S. Yang, Z. Bo, "Development of a New Permanent-Magnet BLDC Generator Using 12-Phase Half-Wave Rectifier," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2023-2029, June 2009.   Abstract Link    Full Text

Abstract: Six-phase double-star armature windings of a synchronous generator are essentially equivalent to 12-phase symmetrical windings displaced in turn by 30$^{circ}$. This paper proposes and implements a new permanent-magnet brushless dc (BLDC) generator using 12-phase half-wave rectifier. Characteristic of output voltage is analyzed according to the star graph of slot potential, and the design constraints of armature windings are provided. Simulation models of 12-phase synchronous generator with half-wave rectifier and double-star synchronous generator with bridge rectifier are established separately. Field-circuit-coupled analysis is accomplished, and conducted modes of rectified diodes and output characteristic are obtained. It is shown that the current stress of diodes in 12-phase rectification system is less than half of that in double-star rectification system, and the output voltage fluctuation between the two different rectification systems is similar. Experimental results on prototype machine, which agree well with the simulation analysis, also verify the feature of the proposed BLDC generator system.


Machines and Drives
56.6.22    Q. Gao, G. M. Asher, M. Sumner, L. Empringham, "Position Estimation of a Matrix-Converter-Fed AC PM Machine From Zero to High Speed Using PWM Excitation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2030-2038, June 2009.   Abstract Link    Full Text

Abstract: This paper describes a sensorless position estimation method for a permanent-magnet (PM) motor fed from a three-phase matrix converter using only its space-vector pulsewidth-modulation (SVPWM) sequence. The scheme employs measurements of $di/dt$ of the motor line currents to construct orthogonal “resolverlike” position signals. In principle, the SVPWM waveforms provide sufficient excitation to extract the position signal from the motor current. However, in order to improve the signal-to-noise ratio of the $di/dt$ signals, a small modification to the SVPWM is required. Sensorless control of the PM synchronous motor at zero and high speeds is demonstrated experimentally. The use of alternative input voltage vectors is also investigated to reduce the current ripple.

56.6.23    J.-W. Choi, S.-C. Lee, "Antiwindup Strategy for PI-Type Speed Controller," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2039-2046, June 2009.   Abstract Link    Full Text

Abstract: This paper proposes a new antiwindup strategy for PI speed controller to suppress the undesired side effect known as integrator windup when large set-point changes are made. When the speed control mode is changed from P control to PI control, an appropriate initial value for the integrator is assigned. This value then restricts the overshoot. In addition, the proposed method guarantees the designed performance independent of the operating conditions, i.e., different set-point changes and load torques, and can be easily implemented with existing PI controllers. In SIMULINK/MATLAB-based comparative simulations and experiments for a permanent-magnet synchronous motor speed controller, the proposed method shows a superior control performance compared with the existing well-known antiwindup methods, such as conditional integration and tracking back calculation.

56.6.24    M. Jones, S. N. Vukosavic, E. Levi, "Parallel-Connected Multiphase Multidrive Systems With Single Inverter Supply," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2047-2057, June 2009.   Abstract Link    Full Text

Abstract: Since independent control of an ac machine requires only two currents, additional degrees of freedom that exist in multiphase $(n ≫ 3)$ machines can be used for other purposes. One possibility is the series connection of the stator windings, in an appropriate manner, which enables independent control of a set of machines although a single multiphase voltage-source inverter (VSI) is used as the supply. The concept has been explored recently in a considerable depth. This paper examines an alternative to the series connection, parallel connection of a multitude of multiphase machines supplied from a single VSI. This eliminates a shortcoming of the series arrangement, the requirement to have open-end stator winding machines. The general principles of paralleling the multiphase machines to a single multiphase VSI are at first set forth, with the subsequent development concentrating on the two-motor five-phase drive system. Dynamic and steady-state models of the two-motor drive are developed, and the vector control scheme is explained. Theoretical findings are verified by extensive experimental investigation on a laboratory setup. It is shown that parallel-connected multiphase multimotor drives represent an advanced example of the well-known analogy between series and parallel connection in electrical engineering. The quality of dynamic performance is the same as with series-connected drive systems. However, parallel connection suffers from a number of serious shortcomings that will prevent its application in industry.

56.6.25    C. Xia, Z. Li, T. Shi, "A Control Strategy for Four-Switch Three-Phase Brushless DC Motor Using Single Current Sensor," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2058-2066, June 2009.   Abstract Link    Full Text

Abstract: A control strategy based on single current sensor is proposed for a four-switch three-phase brushless dc (BLDC) motor system to lower cost and improve performance. The system's whole working process is divided into two groups. In modes 2, 3, 5, and 6, where phase c works, phase- c current is sensed to control phases a and b, and phase-c current is consequently regulated. In modes 1 and 4, the combination of four suboperating modes for controlling phase-c current is proposed based on detailed analysis on the different rules that these operating modes have on phase-c current. Phase-c current is maintained at nearly zero level first, and phase- a and phase-b currents are regulated by speed circle. To improve control performance, a single-neuron adaptive proportional–integral (PI) algorithm is adopted to realize the speed regulator. Simulation and experimental systems are set up to verify the proposed strategy. According to simulation and experimental results, the proposed strategy shows good self-adapted track ability with low current ripple and strong robustness to the given speed reference model. Also, the structure of the drive is simplified.

56.6.26    C. A. Baguley, U. K. Madawala, "The Impact of Circuit Variables on the Starting Performance of Field-Aligned Starting," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2067-2075, June 2009.   Abstract Link    Full Text

Abstract: Field-aligned starting (FAS) is a new technique for starting three-phase cage induction motors on either three- or single-phase supply lines with minimal inrush currents. FAS generates a high impulselike torque to start the motor that is independent of the mains supply, before connecting the already spinning motor to the mains supply. In contrast to conventional starting techniques, FAS imposes higher than normal/rated voltage and current conditions on the machine at starting, and as such, the transient performance of FAS operated motors is complex in nature and largely governed by a number of key circuit variables, the values of which are critical for an efficient and economical design of FAS. A detailed insight into the influence of these key parameters on transient performance during startup is essential to avoid time consuming and inefficient trial and error design methods currently utilized in FAS designs. This paper addresses this need through the investigation of both the functionality and the extent of impact of the key variables on the starting performance of FAS. A transient model is utilized, and both experimental and simulated results suggest that, for a given set of circuit components, the proper selection of variable values is critical to achieve the best possible performance at startup.

56.6.27    K. Raggl, B. Warberger, T. Nussbaumer, S. Burger, J. W. Kolar, "Robust Angle-Sensorless Control of a PMSM Bearingless Pump," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2076-2085, June 2009.   Abstract Link    Full Text

Abstract: In the semiconductor industry, where bearingless pump systems are employed as the state-of-the-art technology, the trend goes toward higher fluid temperatures (150 $^{circ}hbox{C}$ and more) in order to further increase process efficiency. This fact translates into the requirement of a high-temperature bearingless pump system and/or the elimination of thermal-critical components such as Hall sensors. This paper introduces a new method for a hall-sensorless control of a permanent-magnet synchronous machine bearingless pump in its operating range from 0 to 8000 r/min and from zero load to full load. The sensorless operation is performed by the following three novel control functionalities: a controlled startup routine, enabling a sure levitation and zero-angle setting; an open-loop angle estimation based on stator voltage and stator current measurement and known machine parameters; and an angle synchronization establishing a robust operation of the pump in the whole operating range even for a large machine parameter drift. In particular, considering the temperature degrading of the permanent-magnet flux density, the novel robust control concept is of great benefit for bearingless pump systems employed in high-temperature applications.

56.6.28    D. Yin, S. Oh, Y. Hori, "A Novel Traction Control for EV Based on Maximum Transmissible Torque Estimation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2086-2094, June 2009.   Abstract Link    Full Text

Abstract: Controlling an immeasurable state with an indirect control input is a difficult problem faced in traction control of vehicles. Research on motion control of electric vehicles (EVs) has progressed considerably, but traction control has not been so sophisticated and practical because of this difficulty. Therefore, this paper takes advantage of the features of driving motors to estimate the maximum transmissible torque output in real time based on a purely kinematic relationship. An innovative controller that follows the estimated value directly and constrains the torque reference for slip prevention is then proposed. By analysis and comparison with prior control methods, the resulting control design approach is shown to be more effective and more practical, both in simulation and on an experimental EV.


Single-Phase Electronics
56.6.29    M. S. Agamy, P. K. Jain, "A Three-Level Resonant Single-Stage Power Factor Correction Converter: Analysis, Design, and Implementation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2095-2107, June 2009.   Abstract Link    Full Text

Abstract: This paper presents a new single-stage power factor correction ac/dc converter based on a three-level half-bridge resonant converter topology. The proposed circuit integrates the operation of the boost power factor preregulator and the three-level resonant dc/dc converter. A variable-frequency asymmetrical pulsewidth modulation controller is proposed for this converter. This control technique is based on two integrated control loops: the output voltage is regulated by controlling the switching frequency of the resonant converter, whereas the dc-bus voltage and input current are regulated by means of duty cycle control of the boost part of the converter. This provides a regulated output voltage and a nearly constant dc-bus voltage regardless of the loading condition; this, in turn, allows using smaller switches and consequently having a lower on resistance helping to reduce conduction losses. Zero-voltage switching is also achieved for a wide range of loading and input voltage. The resulting circuit, therefore, has high conversion efficiency making it suitable for high-power wide-input-voltage-range applications. The effectiveness of this method is verified on a 2.3-kW 48-V converter with input voltage (90–265 Vrms).

56.6.30    M. R. Amini, H. Farzanehfard, "Novel Family of PWM Soft-Single-Switched DC–DC Converters With Coupled Inductors," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2108-2114, June 2009.   Abstract Link    Full Text

Abstract: In this paper, a novel family of pulsewidth-modulation soft-single-switched dc–dc converters without high voltage and current stresses is described. These converters do not require any extra switch to achieve soft switching, which considerably simplifies the control circuit. In all converter family members, the switch is turned on under zero-current condition and is turned off at almost zero-voltage condition. From the proposed converter family, the boost topology is analyzed, and its operating modes are explained. The presented experimental results of a prototype boost converter confirm the theoretical analysis.

56.6.31    W. G. Hurley, Y. S. Wong, W. H. Wolfle, "Self-Equalization of Cell Voltages to Prolong the Life of VRLA Batteries in Standby Applications," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2115-2120, June 2009.   Abstract Link    Full Text

Abstract: The valve-regulated lead-acid battery has been the work horse of standby applications for several decades. Float charging is normally implemented in these systems. However, float charging tends to overcharge the battery, causing water loss and grid corrosion which shorten the service life of the battery. This limitation may be avoided by using cell voltage equalization and temperature-compensated interrupted charge control (TCICC). Cell voltage equalization reduces the voltage distribution range over many cells, which, in turn, means that there are fewer cells with either overvoltage or undervoltage, both of which shorten the life of the battery. TCICC can increase the service life of the battery by avoiding overvoltage. Experimental evidence is presented to validate the new approach by comparing float charging and TCICC in terms of battery voltage equalization and temperature response.

56.6.32    Y.-K. Lin, Y.-S. Lai, "Dead-Time Elimination of PWM-Controlled Inverter/Converter Without Separate Power Sources for Current Polarity Detection Circuit," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2121-2127, June 2009.   Abstract Link    Full Text

Abstract: This paper will present a dead-time elimination scheme for a pulsewidth-modulation (PWM)-controlled inverter/converter. The presented dead-time elimination scheme does not require separated power supplies for freewheeling-current detection of high- and low-side power devices. The presented scheme includes the freewheeling-current polarity detection circuit and the PWM control generator without dead time. It will be shown that the presented scheme eliminates the dead time of PWM control for inverter/converter and therefore dramatically improves output voltage loss and current distortion. Experimental results derived from a field-programmable-gate-array-based PWM-controlled inverter are shown to demonstrate the effectiveness.

56.6.33    D. D.-C. Lu, H. H.-C. Iu, V. Pjevalica, "Single-Stage AC/DC Boost–Forward Converter With High Power Factor and Regulated Bus and Output Voltages," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2128-2132, June 2009.   Abstract Link    Full Text

Abstract: Unlike existing single-stage ac/dc converters with uncontrolled intermediate bus voltage, a new single-stage ac/dc converter achieving power factor correction (PFC), intermediate bus voltage output regulation, and output voltage regulation is proposed. The single-power-stage circuit is formed by integrating a boost PFC converter with a two-switch-clamped forward converter. The current stress of the main power switches is reduced due to separated conduction period of the two source currents flowing through the power switch. A dual-loop peak-current-mode controller is proposed to achieve PFC and ensure independent bus voltage and output voltage regulations. Experimental results on a 24-V/100-W hardware prototype are given to confirm the theoretical analysis and performance of the proposed converter. The converter has conversion efficiency ranging from 86% to 92% at full-load condition.

56.6.34    B. Abdi, A. H. Ranjbar, G. B. Gharehpetian, J. Milimonfared, "Reliability Considerations for Parallel Performance of Semiconductor Switches in High-Power Switching Power Supplies," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2133-2139, June 2009.   Abstract Link    Full Text

Abstract: In order to ensure increasing current rating of semiconductor switches, paralleling is unavoidable. In this paper, the paralleling of switches has been studied from the reliability point of view. A prototype 4-kW boost converter has been used for this paper. In this boost converter, five insulated gate bipolar transistors are paralleled per switch in order to increase the current rating. Based on experimental results, the reliability of converter has been calculated. Results of reliability calculations showed that paralleling switches extremely decreases reliability of dc–dc converters. The same converter has been constructed by using an integrated power module (IPM). The same calculations have been repeated for the IPM-based converter. The comparison of the results shows that the case of IPM in converters can increase the reliability of the circuit.

56.6.35    J. Sallan, J. L. Villa, A. Llombart, J. F. Sanz, "Optimal Design of ICPT Systems Applied to Electric Vehicle Battery Charge," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2140-2149, June 2009.   Abstract Link    Full Text

Abstract: Although the use of inductively coupled power transfer (ICPT) systems for electric vehicle battery charge presents numerous advantages, a detailed design method cannot be found in the literature. This paper shows the steps to follow in the optimized design of an ICPT system and the results obtained in their application to the four most common compensation topologies, pointing out the best one in terms of minimum copper mass and proper stability conditions. A new design factor $K_{rm D}$ is proposed to select the optimum configuration for each topology. Finally, the theoretical results are validated on a 2-kW prototype with a 15-cm air gap between coils.

56.6.36    Y. Suh, Y. Lee, P. K. Steimer, "A Comparative Study of Medium-Voltage Power Converter Topologies for Plasma Torch Under Dynamic Operating Conditions," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2150-2161, June 2009.   Abstract Link    Full Text

Abstract: This paper compares several medium-voltage power conversion systems for plasma torch application. The thermal plasma torch rated for 3 MW, 2 kA with the physical size of 1 m long is selected. The dynamic characteristics of the dc arc in a plasma torch are investigated using advanced 3-D magnetohydrodynamics simulation. The arc voltage noise of $pm$10% due to the periodic pressure wave is modeled as a sawtooth waveform in arc power loss term. The parameters of the Cassie–Mayr arc model are calculated based on 3-D simulation. A 12-pulse thyristor rectifier and two-phase staggered three-level step-down dc–dc converter having 12-pulse front-end diode rectifier are compared under the same dynamic operating condition. The three-level dc–dc converter has superior dynamic performance over the 12-pulse thyristor rectifier under the existence of arc disturbance noise. This power converter topology provides higher ignition voltage around 5 kV during ignition phase and higher arc stability.


Renewable Energy Systems
56.6.37    S. Alepuz, S. Busquets-Monge, J. Bordonau, J. A. Martinez-Velasco, C. A. Silva, J. Pontt, J. Rodriguez, "Control Strategies Based on Symmetrical Components for Grid-Connected Converters Under Voltage Dips," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2162-2173, June 2009.   Abstract Link    Full Text

Abstract: Low-voltage ride-through (LVRT) requirements demand wind-power plants to remain connected to the network in presence of grid-voltage dips. Most dips present positive-, negative-, and zero-sequence components. Hence, regulators based on symmetrical components are well suited to control grid-connected converters. A neutral-point-clamped topology has been considered as an active front end of a distributed power-generation system, following the trend of increasing power and voltage levels in wind-power systems. Three different current controllers based on symmetrical components and linear quadratic regulator have been considered. The performance of each controller is evaluated on LVRT requirement fulfillment, grid-current balancing, maximum grid-current value control, and oscillating power flow. Simulation and experimental results show that all three controllers meet LVRT requirements, although different system performance is found for each control approach. Therefore, controller selection depends on the system constraints and the type of preferred performance features.

56.6.38    G. Ma, W. Qu, G. Yu, Y. Liu, N. Liang, W. Li, "A Zero-Voltage-Switching Bidirectional DC–DC Converter With State Analysis and Soft-Switching-Oriented Design Consideration," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2174-2184, June 2009.   Abstract Link    Full Text

Abstract: This paper proposes a new soft-switching bidirectional dc/dc converter. The proposed converter achieves zero-voltage switching (ZVS) for the entire main switches and zero-current switching for the rectifier diodes in the large-load range. These features reduce switching loss, voltage and current stresses, and diode reverse-recovery effect. The simple electrical isolated topology with the soft-switching characteristic provides an attractive solution for a battery charge/discharge system in an electric vehicle, distributed power system, or uninterruptible power system. This paper describes the operation principle and the ZVS condition in detail. The mathematical model based on the state-space averaging method is also deduced to depict the performance characteristic. Then, design guidelines are presented to ensure the ZVS condition for all the switches. Finally, simulation and experimental results obtained from a 1-kW prototype verify the discussed theoretical analysis.

56.6.39    D. Yazdani, A. Bakhshai, G. Joos, M. Mojiri, "A Real-Time Extraction of Harmonic and Reactive Current in a Nonlinear Load for Grid-Connected Converters," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2185-2189, June 2009.   Abstract Link    Full Text

Abstract: This paper introduces a new adaptive notch filtering approach to extract the harmonic and reactive current components for power quality purposes in grid-connected converters. The main function of this method is to provide synchronized harmonic and reactive current components for control purposes. The theoretical analysis is presented, and the performance of the method is experimentally evaluated. The methodology is applicable for a wide range of equipment such as uninterrupted power supplies, regenerative converters, active power filters, etc., as a basis for generating the reference signals.


Motors and Actuators
56.6.40    J. Moreno-Valenzuela, R. Campa, "Two Classes of Velocity Regulators for Input-Saturated Motor Drives," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2190-2202, June 2009.   Abstract Link    Full Text

Abstract: This paper deals with the velocity control of motor drives when saturated inputs are considered. Two classes of velocity controllers guaranteeing exponential stability are introduced. The first controller allows nonlinear proportional an integral action, while the other one includes an antiwindup loop. A detailed experimental study is provided, which confirms the theoretical results.

56.6.41    M.-J. Yang, H.-L. Jhou, B.-Y. Ma, K.-K. Shyu, "A Cost-Effective Method of Electric Brake With Energy Regeneration for Electric Vehicles," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2203-2212, June 2009.   Abstract Link    Full Text

Abstract: This paper proposes a simple but effective method of electric brake with energy regeneration for a brushless dc motor of an electric vehicle (EV). During the braking period, the proposed method only changes the switching sequence of the inverter to control the inverse torque so that the braking energy will return to the battery. Compared with the presented methods, the proposed solution simultaneously achieves dual goals of the electric brake and the energy regeneration without using additional converter, ultracapacitor, or complex winding-changeover technique. Since the braking kinetic energy is converted into the electrical energy and then returns to the battery, the energy regeneration could increase the driving range of an EV. In addition to the braking period, the duration of release throttle is also included in the energy-regenerative mechanism such that the EV is similar to engine vehicles having the engine brake. Therefore, the electric brake can improve rider's comfort and enhance the EV's safety. Finally, the feasibility of the proposed method is demonstrated by experimental results. It shows that the driving range of the EV could be increased to about 16.2%.

56.6.42    S.-M. Yang, M.-S. Huang, "Design and Implementation of a Magnetically Levitated Single-Axis Controlled Axial Blood Pump," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2213-2219, June 2009.   Abstract Link    Full Text

Abstract: This paper presents the design and implementation of a magnetically levitated axial blood pump. The rotor has a hollow structure for fluid flow, and the impeller is mounted on the rotor inner surface. The magnetic suspension system is realized using two passive magnetic bearings for radial direction balancing and an electromagnetic actuator for axial direction balancing. A sensor assembly for the rotor's axial position control is also presented. This sensor can measure axial displacement with good accuracy. A prototype pump was built and investigated. The experimental results demonstrate successful magnetic levitation and water-pumping operations. Because radial movements were not actively controlled, noticeable oscillations existed in these directions. These oscillations were caused mainly by the radial force produced by the actuator.


Signal Processing and Control
56.6.43    G. W. Chang, C. Chen, Q.-W. Liang, "A Two-Stage ADALINE for Harmonics and Interharmonics Measurement," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2220-2228, June 2009.   Abstract Link    Full Text

Abstract: Harmonics and interharmonics may introduce operational problems in electrical and electronic equipment. Therefore, monitoring harmonics/interharmonics for improving the power quality is of importance for both electric utilities and their customers. In this paper, a cascaded two-stage adaptive linear element (ADALINE) structure for both harmonics and interharmonics measurement is proposed. In addition, a simple laboratory setup implemented by MATLAB and the dedicated hardware for measuring power signals is built to verify the performance of proposed method. Results are compared with those obtained by short-time Fourier transform and two other conventional ADALINE-based methods. It shows that the proposed method is with a better accuracy, even if the power frequency deviation and interharmonic components are present in the measured signal. The proposed method also can be adopted for harmonic/interharmonic compensation devices in real time.

56.6.44    H. Huerta, A. G. Loukianov, J. M. Canedo, "Multimachine Power-System Control: Integral-SM Approach," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2229-2236, June 2009.   Abstract Link    Full Text

Abstract: In this paper, a robust nonlinear control scheme based on the combination of the block-control linearization and integral sliding modes is proposed. This control technique is applied to multimachine electric-power systems. The plant model takes into account the interactions in power systems between the electrical and mechanical dynamics and load constraints. A nonlinear observer is designed to estimate the synchronous generators' rotor fluxes. The proposed control scheme requires only local information of each generator. The considered controller was tested and compared with a classical one through simulation on the Western System Coordinating Council system.

56.6.45    L. Guo, J. Y. Hung, R. M. Nelms, "Evaluation of DSP-Based PID and Fuzzy Controllers for DC–DC Converters," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2237-2248, June 2009.   Abstract Link    Full Text

Abstract: In this paper, digital proportional–integral–derivative (PID)-type and fuzzy-type controllers are compared for application to the buck and boost dc–dc converters. Comparison between the two controllers is made with regard to design methodology, implementation issues, and experimentally measured performance. Design of fuzzy controllers is based on heuristic knowledge of converter behavior, and tuning requires some expertise to minimize unproductive trial and error. The design of PID control is based on the frequency response of the dc–dc converter. Implementation of linear controllers on a digital signal processor is straightforward, but realization of fuzzy controllers increases computational burden and memory requirements. For the boost converter, the performance of the fuzzy controller was superior in some respects to that of the PID controllers. The fuzzy controller was able to achieve faster transient response in most tests, had a more stable steady-state response, and was more robust under some operating conditions. In the case of the buck converter, the fuzzy controller and PID controller yielded comparable performances.

56.6.46    Y. Liu, H. Hong, A. Q. Huang, "Real-Time Algorithm for Minimizing THD in Multilevel Inverters With Unequal or Varying Voltage Steps Under Staircase Modulation," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2249-2258, June 2009.   Abstract Link    Full Text

Abstract: Different modulation methods have been proposed to control the multilevel inverters. This paper focuses on the staircase modulation that is very popular for multilevel inverters with low switching frequencies. Nonreal-time algorithms for the staircase modulation cannot be applied practically in multilevel inverters with varying voltage steps, since the sizes of lookup tables would be huge. We propose a real-time algorithm for multilevel inverters with unequal or varying voltage steps under the staircase modulation. The algorithm results in the minimal total harmonic distortion (THD) of the output voltage of the inverter, which is proved by rigorous mathematical derivations in this paper. A new expression of THD is presented to simplify the derivation significantly. Computational complexity of the algorithm is analyzed to estimate the time cost of the calculation. We implemented the algorithm on a digital signal processor and provide experimental results that verify the performance of the proposed algorithm.

56.6.47    Y. Liu, A. Q. Huang, W. Song, S. Bhattacharya, G. Tan, "Small-Signal Model-Based Control Strategy for Balancing Individual DC Capacitor Voltages in Cascade Multilevel Inverter-Based STATCOM," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2259-2269, June 2009.   Abstract Link    Full Text

Abstract: This paper presents a new feedback control strategy for balancing individual dc capacitor voltages in a three-phase cascade multilevel inverter-based static synchronous compensator. The design of the control strategy is based on the detailed small-signal model. The key part of the proposed controller is a compensator to cancel the variation parts in the model. The controller can balance individual dc capacitor voltages when H-bridges run with different switching patterns and have parameter variations. It has two advantages: 1) the controller can work well in all operation modes (the capacitive mode, the inductive mode, and the standby mode) and 2) the impact of the individual dc voltage controller on the voltage quality is small. Simulation results and experimental results verify the performance of the controller.

56.6.48    F. Vargas-Merino, M. J. Meco-Gutierrez, J. R. Heredia-Larrubia, A. Ruiz-Gonzalez, "Low Switching PWM Strategy Using a Carrier Wave Regulated by the Slope of a Trapezoidal Modulator Wave," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2270-2274, June 2009.   Abstract Link    Full Text

Abstract: A simple and novel pulsewidth modulation (PWM) technique is presented. It uses a trapezoidal modulator wave and a sinusoidal carrier signal with variable frequency. The instantaneous frequency of the carrier wave is proportional to the slope of the modulator signal, and only two parameters (the slope of the trapezoidal edges and the proportionality constant of the carrier wave frequency) allow one to control the output voltage level and the number of commutation per cycle in real time. The proposed technique generates high-quality voltages with very few commutations per cycle, and it is particularly appropriate for reducing commutation loss. Results are checked experimentally and compared to other PWM techniques, yielding better signal quality with an important reduction in the number of commutations.


Diagnosis and Monitoring
56.6.49    P. Lezana, R. Aguilera, J. Rodriguez, "Fault Detection on Multicell Converter Based on Output Voltage Frequency Analysis," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2275-2283, June 2009.   Abstract Link    Full Text

Abstract: Multilevel converters use a large amount of semiconductors, allowing the reconfigurate of the converter to work even on internal fault condition. This paper presents a method to detect faulty cells in a cascaded multicell converter requiring just one voltage measurement per output phase. The method is based on high-frequency harmonic analysis, using a dynamic prediction of their behavior, avoiding erroneous detection on transients while keeping the precision under real fault events. Once the faulty cell is detected, it can be bypassed allowing the converter to keep working according to previously reported techniques. Experimental results confirm accurate and fast fault detection, with a good rejection to normal operation transients.


Networking


56.6.50    D.-Z. Sun, J.-P. Huai, J.-Z. Sun, J.-X. Li, J.-W. Zhang, Z.-Y. Feng, "Improvements of Juang 's Password-Authenticated Key Agreement Scheme Using Smart Cards," IEEE Trans. on Industrial Electronics, vol. 56, no. 6, pp. 2284-2291, June 2009.   Abstract Link    Full Text

Abstract: In the IEEE Transactions on Industrial Electronics, vol. 55, no. 6, Juang proposed a password-authenticated key agreement scheme using smart cards. Although the scheme of Juang has many benefits, we find that it suffers from three weaknesses: 1) inability of the password-changing operation; 2) the session-key problem; and 3) inefficiency of the double secret keys. Therefore, we propose an improved scheme to overcome the weaknesses and maintain the benefits of the original scheme. In addition, our improved scheme reduces the storage and computation costs on the smart card compared with the scheme of Juang We believe that our improved scheme is more suitable for real-life applications than that of Juang