IEEE Transactions on Industrial Electronics
Special Section Papers on Renewable Energy
And Distributed Genarated Systems - Part 2 : Control of Distributed
Generation Systems
1. F. Blaabjerg, R. Teodorescu, M. Liserre, A.V. Timbus, "Overview of Control and Grid Synchronization for Distributed Power Generation Systems," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1398-1409, Oct. 2006. Full Text Link
Abstract: Renewable energy sources like wind, sun, and hydro are seen as a reliable alternative to the traditional energy sources such as oil, natural gas, or coal. Distributed power generation systems (DPGSs) based on renewable energy sources experience a large development worldwide, with Germany, Denmark, Japan, and USA as leaders in the development in this field. Due to the increasing number of DPGSs connected to the utility network, new and stricter standards in respect to power quality, safe running, and islanding protection are issued. As a consequence, the control of distributed generation systems should be improved to meet the requirements for grid interconnection. This paper gives an overview of the structures for the DPGS based on fuel cell, photovoltaic, and wind turbines. In addition, control structures of the grid-side converter are presented, and the possibility of compensation for low-order harmonics is also discussed. Moreover, control strategies when running on grid faults are treated. This paper ends up with an overview of synchronization methods and a discussion about their importance in the control
2. S. Pavljaevic, F. Dawson, "Synchronization to Disturbed Utility-Network Signals Using a Multirate Phase-Locked Loop," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1410-1417, Oct. 2006. Full Text Link
Abstract: This paper presents a digital-signal-processing system suitable for synchronization in applications where the synchronization signal is severely disturbed, and where the signal frequency and amplitude are variable. The system is based on a multirate phase-locked loop. The main advantages of the multirate approach are that it relaxes the implementation of the antialiasing filter, and it enables one to accommodate the varying amplitude of the input signal. The antialiasing filter, which is in this case a high-order bandpass filter, is implemented in the digital part of the system. This feature is achieved by applying the oversampling technique to the input signal. The antialiasing filter automatically adapts to the input-signal-frequency variations through the system's variable sample-rate operation. This paper deals with modeling, analysis, control, and implementation issues of the proposed system. The system is implemented on a platform based on the Texas Instruments TMS320C31 digital signal processor. Tracking properties of the implemented system are verified with realistic signals such as a sinusoidal signal containing notch-type disturbance and noise and an arc-furnace voltage signal
3. M. Liserre, A. Pigazo, A. Dell'Aquila, V.M. Moreno, "An Anti-Islanding Method for Single-Phase Inverters Based on a Grid Voltage Sensorless Control," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1418-1426, Oct. 2006. Full Text Link
Abstract: The detection of the islanding condition of a distributed generation (DG) system is crucial for safety reasons, as discussed in the IEEE standards and specifically required by some national codes. Several anti-islanding methods that are resident in the inverter have been investigated and classified as passive (measurement of the natural effects of islanding) or active (based on the measurement of the effects due to transients or harmonics deliberately introduced in the system). In case the power drained by the load matches the power generated by the DG inverter, the effect of islanding is small, and the passive methods fail. However, the active methods, which have been developed to overcome these limits, create disturbances that can interact with those generated by other DG systems. In this paper, a new anti-islanding method is proposed. It exploits the natural sensitivity of a grid-voltage sensorless control to disturbances to highlight the islanding condition. The adopted grid-voltage sensorless control is adapted to a single-phase system with the use of resonant controllers based on the internal model control law: resonant-controller-based observer results. Then, a Kalman-filter-based algorithm is used to detect the islanding condition based on the energy mismatch between the estimated third and fifth harmonics and the real ones. Experimental results support the analysis
4. D.M. Vilathgamuwa, P.C. Loh, Y. Li, "Protection of Microgrids During Utility Voltage Sags," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1427-1436, Oct. 2006. Full Text Link
Abstract: Microgrids are systems with clusters of microgenerators, which are installed for distributed power generation. When interfaced to the utility grid, microgrids are exposed to common utility power-quality disturbances. In particular, during utility-voltage sags, large line currents can flow along distribution feeders connecting the micro- and utility grids. To limit this flow of large line currents and, hence, protect the microgrids, this paper proposes two current-limiting algorithms, namely, the RL feedforward and flux-charge-model feedback algorithms, for controlling a series inverter connected between the micro- and utility grids during utility voltage sags. Both methods function by inserting a large virtual RL or L impedance in series with the distribution feeder to limit the line-current flow. Detailed descriptions, controller designs, and comparisons of both algorithms are presented. Phasor analyses of both methods are also presented to show how the inserted RL or L values can be optimally tuned to improve the inverter damping performance and minimize its injected voltages and circulating power under all operation conditions. Lastly, both methods have been tested in simulation and in experiments using an emulated laboratory microgrid system
5. B. Singh, S.S. Murthy, S. Gupta, "STATCOM-Based Voltage Regulator for Self-Excited Induction Generator Feeding Nonlinear Loads," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1437-1452, Oct. 2006. Full Text Link
Abstract: This paper deals with the performance analysis of a static compensator (STATCOM)-based voltage regulator for self-excited induction generators (SEIGs) supplying nonlinear loads. In practice, a number of loads are nonlinear in nature, and therefore, they inject harmonics in the generating systems. The SEIG's performance, being a weak isolated system, is very much affected by these harmonics. The additional drawbacks of the SEIG are poor voltage regulation and that it requires an adjustable reactive power source with varying loads to maintain a constant terminal voltage. A three-phase insulated-gate-bipolar-transistor-based current-controlled voltage source inverter working as STATCOM is used for harmonic elimination, and it provides the required reactive power for the SEIG, with varying loads to maintain a constant terminal voltage. A dynamic model of the SEIG-STATCOM feeding nonlinear loads using stationary d-q axes reference frame is developed for predicting the behavior of the system under transient conditions. The simulated results show that SEIG terminal voltage is maintained constant, even with nonlinear balanced and unbalanced loads, and free from harmonics using STATCOM-based voltage regulator
6. J. Schonbergerschonberger, R. Duke, S.D. Round, "DC-Bus Signaling: A Distributed Control Strategy for a Hybrid Renewable Nanogrid," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1453-1460, Oct. 2006. Full Text Link
Abstract: A dc nanogrid is a hybrid renewable system since renewable sources supply the average load demand, while storage and nonrenewable generation maintain the power balance in the presence of the stochastic renewable sources. The system is power electronic based, with converters being used to interface both the sources and loads to the system. The nanogrid is controlled using dc-bus signaling (DBS), a distributed control strategy in which the control nodes, the source/storage interface converters, induce voltage-level changes to communicate with the other control nodes. This paper explains the control structure required for the converters to permit the use of DBS, and explains a procedure for implementing a system-wide control law through independent control of the source/storage interface converters. Experimental results are presented to demonstrate the operation of this novel control strategy
7. J.M. Guerrero, J. Matas, L. Garcia De Vicunagarcia De Vicuna, M. Castilla, J. Miret, "Wireless-Control Strategy for Parallel Operation of Distributed-Generation Inverters," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1461-1470, Oct. 2006. Full Text Link
Abstract: In this paper, a method for the parallel operation of inverters in an ac-distributed system is proposed. This paper explores the control of active and reactive power flow through the analysis of the output impedance of the inverters and its impact on the power sharing. As a result, adaptive virtual output impedance is proposed in order to achieve a proper reactive power sharing, regardless of the line-impedance unbalances. A soft-start operation is also included, avoiding the initial current peak, which results in a seamless hot-swap operation. Active power sharing is achieved by adjusting the frequency in load transient situations only, owing to which the proposed method obtains a constant steady-state frequency and amplitude. As opposed to the conventional droop method, the transient response can be modified by acting on the main control parameters. Linear and nonlinear loads can be properly shared due to the addition of a current harmonic loop in the control strategy. Experimental results are presented from a two-6-kVA parallel-connected inverter system, showing the feasibility of the proposed approach
8. M. Prodanovic, T.C. Green, "High-Quality Power Generation Through Distributed Control of a Power Park Microgrid," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1471-1482, Oct. 2006. Full Text Link
Abstract: Inverters are a necessary interface for several forms of distributed generation (DG) and where they form a microgrid they have the potential to offer high power quality. The challenge is to coordinate the actions of a group of inverters so that they offer the level of power quality known to be possible from fast local control of a single inverter. The case examined here is a power park of several inverter-based DG in relatively close proximity. A basic requirement is that the inverters regulate the grid voltage and share the real and reactive power demands according to their ratings. In small girds with high proportions of nonlinear and unbalanced loads it is also important to actively control the waveform quality in terms of harmonics, transient disturbances, and balance. Further, it is important that these duties are shared equally between the units rather than having one master unit taking the lead in the voltage control function. A constraint faced in designing a sharing system is the limited bandwidth of signal communication even over distances of a few meters. A control method is proposed that separates the control tasks in the frequency domain. Power sharing and voltage regulation are controlled centrally and commands are distributed through a low-bandwidth communication link. Waveform quality functions are controlled in high bandwidth controllers distributed to each local inverter. Experimental tests on a grid of three 10-kVA inverters are used to show that the method fully exploits the inherent fast response of the inverters while also ensuring voltage balance even with extreme load imbalance. It is shown that circulating currents are avoided during steady state and transients
9. R.C. Portillo, M.M. Prats, J.I. Leon, J.A. Sanchez, J.M. Carrasco, E. Galvan, L.G. Franquelo, "Modeling Strategy for Back-to-Back Three-Level Converters Applied to High-Power Wind Turbines," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1483-1491, Oct. 2006. Full Text Link
Abstract: Three-level converters are becoming a realistic alternative to the conventional converters in high-power wind-energy applications. In this paper, a complete analytical strategy to model a back-to-back three-level converter is described. This tool permits us to adapt the control strategy to the specific application. Moreover, the model of different loads can be incorporated to the overall model. Both control strategy and load models are included in the complete system model. The proposed model pays special attention to the unbalance in the capacitors' voltage of three-level converters, including the dynamics of the capacitors' voltage. In order to validate the model and the control strategy proposed in this paper, a 3-MW three-level back-to-back power converter used as a power conditioning system of a variable speed wind turbine has been simulated. Finally, the described strategy has been implemented in a 50-kVA scalable prototype as well, providing a satisfactory performance
10. K. Jin, X. Ruan, "Hybrid Full-Bridge Three-Level LLC Resonant Converter—A Novel DC–DC Converter Suitable for Fuel-Cell Power System," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1492-1503, Oct. 2006. Full Text Link
Abstract: This paper proposes a novel hybrid full-bridge (H-FB) three-level (TL) LLC resonant converter. It integrates the advantages of the H-FB TL converter and the LLC resonant converter. It can operate under both three-level mode and two-level mode, so it is very suitable for wide-input-voltage-range applications, such as fuel-cell power systems. Compared with the traditional full-bridge converter, the input current ripple and output filter can be reduced. In addition, all the switches can realize zero-voltage switching from nearly zero to full load, and the switches of the TL leg sustain only half of the input voltage. Moreover, the rectifier diodes can achieve zero-current switching, and the voltage stress across them can be minimized to the output voltage. A prototype of 200-400-V input and 360-V/4-A output is built in our laboratory to verify the operation principle of the proposed converter
11. S. Alepuz, S. Busquets-Monge, J. Bordonau, J. Gago, D. Gonzalez, J. Balcells, "Interfacing Renewable Energy Sources to the Utility Grid Using a Three-Level Inverter," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1504-1511, Oct. 2006. Full Text Link
Abstract: This paper presents a novel approach for the connection of renewable energy sources to the utility grid. Due to the increasing power capability of the available generation systems, a three-level three-phase neutral-point-clamped voltage-source inverter is selected as the heart of the interfacing system. A multivariable control law is used for the regulator because of the intrinsic multivariable structure of the system. A current source (playing the role of a generic renewable energy source) is connected to the grid using a three-level inverter in order to verify the good performance of the proposed approach. Large- and small-signal d-q state-space averaged models of the system are obtained and used to calculate the multivariable controller based on the linear quadratic regulator technique. This controller simultaneously regulates the dc-link voltage (to operate at the maximum power point of the renewable energy source), the mains power factor (the power is delivered to the grid at unity power factor), and the dc-link neutral-point voltage balance. With the model and regulator presented, a specific switching strategy to control the dc-link neutral-point voltage is not required. The proposed controller can be used for any application, since its nature makes possible the control of any system variable. The good performance of the presented interfacing solution in both steady-state and transient operation is verified through simulation and experimentation using a 1-kW neutral-point-clamped voltage-source-inverter prototype, where a PC-embedded digital signal processor board is used for the controller implementation
12. Y. Cheng, C. Qian, M.L. Crow, S. Pekarek, S. Atcitty, "A Comparison of Diode-Clamped and Cascaded Multilevel Converters for a STATCOM With Energy Storage," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1512-1521, Oct. 2006. Full Text Link
Abstract: The progression of distributed generation within a bulk power system will lead to the need for greater control of transmission-line power flows. Static synchronous compensators (STATCOMs) provide a power-electronics-based means of embedded control of transmission-line voltage and power flows. The integration of energy storage with a STATCOM can extend traditional STATCOM capabilities to four-quadrant power flow control and transient stability improvement. This paper discusses energy storage systems (ESSs) integrated with conventional and multilevel bidirectional power converters for a hybrid STATCOM/ESS. Conventional, diode-clamped, and cascaded multilevel converter-based STATCOM/ESSs are developed, and their performances for a variety of power system applications are compared using battery energy storage. The advantages and disadvantages of each topology are presented. Both simulation and experimental results are provided to validate the conclusions
13. G.M. Martins, J.A. Pomilio, S. Buso, G. Spiazzi, "Three-Phase Low-Frequency Commutation Inverter for Renewable Energy Systems," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1522-1528, Oct. 2006. Full Text Link
Abstract: The connection of distributed power sources with the utility grid generally needs an electronic power converter for processing the locally generated power and injecting current into the system. If the source provides a dc voltage, the converter must be able to produce a low-distortion high-power-factor ac current. The same aspects related with the voltage and current distortion produced by nonlinear loads can be considered for the injection of power into the grid. In the absence of a specific standard, this paper takes as a reference the limits for current harmonics given by international standards. The justification for this approach is that, from the resulting line voltage degradation, there is no difference between injected and absorbed currents. This paper presents a three-phase inverter using low-frequency commutation. An auxiliary circuit is added to the inverter topology to reduce the output voltage distortion, thus improving the current waveform. The main advantages of this approach are the minimization of the switching losses and the elimination of the electromagnetic interference, which avoids high-frequency filters necessary in high-frequency commutation inverters
14. F.-S. Pai, "An Improved Utility Interface for Microturbine Generation System With Stand-Alone Operation Capabilities," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1529-1537, Oct. 2006. Full Text Link
Abstract: In this paper, an alternative filter and control approach for the design of a microturbine's utility interface is proposed. The new method employs a unified current-regulated controller to drive the system converter as a power conditioner for the grid-tied operation and an emergent generator for the stand-alone operation, where few current sensors are required to serve the controller for both operating modes. The proposed method had been examined under various scenarios, including the loss of grid and parallel operation. The results help consolidate the feasibility and practicability of the approach for the applications considered
Power Electronics
15. Y.-M. Chen, Y.-C. Liu, S.-H. Lin, "Double-Input PWM DC/DC Converter for High-/Low-Voltage Sources," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1538-1545, Oct. 2006. Full Text Link
Abstract: A novel double-input pulsewidth-modulation (PWM) dc/dc converter for high-/low-voltage sources is proposed in this paper. With a PWM control scheme, the proposed double-input dc/dc converter can draw power from two different voltage sources simultaneously or individually. The operation modes and the steady-state analysis of the proposed double-input dc/dc converter are introduced in detail. The PWM control scheme for the power flow balancing is also presented. By using a single passive lossless soft-switching cell, switching losses of all power switches can be reduced significantly. Finally, experimental measurements are demonstrated to verify the performance of the proposed converter
16. S.-K. Han, J.-Y. Lee, G.-W. Moon, M.-J. Youn, "IGBT-Based Cost-Effective Energy-Recovery Circuit for Plasma Display Panel," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1546-1554, Oct. 2006. Full Text Link
Abstract: A new insulated-gate-bipolar-transistor (IGBT)-based cost-effective energy-recovery circuit (ERC) for a plasma display panel (PDP) is proposed. Since it is composed of two small resonant inductors and four power diodes instead of the conventional large auxiliary circuit, it features a simpler structure, less mass, fewer power devices, higher efficiency, and lower cost. Since all its power switches are turned off under the zero-current switching operation, IGBTs can be employed as power switches. Moreover, the very stable and uniform light emitted from a PDP proves the high quality of screen. Therefore, it is well suitable for the consumer-affordable hang-on-the-wall TVs which have the desirable features such as thinness, lightness, high efficiency, low price, etc. To confirm the validity of the proposed ERC, a comparative analysis and experimental results based on a whole ac PDP driver equipped with the proposed circuit for the 42-in PDP are presented
17. H. Chen, E.K.K. Sng, K.J. Tseng, "Optimum Trajectory Switching Control for Series-Parallel Resonant Converter," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1555-1563, Oct. 2006. Full Text Link
Abstract: The series-parallel resonant converter (SPRC) is known to have combined merits of the series resonant converter (SRC) and PRC. However, the SPRC has a three-element LCC structure with complex transient dynamics, and without control of the resonant circuit's dynamics, the converter's closed-loop bandwidth to switching-frequency ratio will be much reduced compared to that of pulsewidth-modulation (PWM) converters. This paper presents the optimal trajectory enabling any SPRC's steady state be achieved within one cycle. Dynamics using the state-plane analysis is presented, and the optimal state trajectory for transients is derived. Experimental results with comparison to frequency control show much reduced resonant circuit response time for step changes in output voltage. This improved resonant circuit control allows subsequent current and voltage-loop controls of the SPRC to be treated as that of a conventional PWM voltage source
18. J.T. Matysik, "A New Method of Integration Control With Instantaneous Current Monitoring for Class D Series-Resonant Converter," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1564-1576, Oct. 2006. Full Text Link
Abstract: In this paper, the application of the integration control method for class D transistor voltage source series-resonant converters used as dc/dc and dc/ac converters is presented. First, the integration control of the signal as a combination of the resonant frequency and its subharmonics (subharmonic integration control) is discussed. Second, the modulation density of the pulses shorting the bridge diagonal for one current half wave (semi wave integral pulse density modulation) is explained. A detailed control circuit operation, referred to as the four basic algorithms of the resonant current control, is given. The method for the calculation of the value and sequence of the current increments for a dc/dc converter is presented. The results of computer simulations and laboratory experiments demonstrate that the proposed methods allow controlling the converter output quantities fulfilling soft switching conditions (zero-current switching) and provide higher efficiency in comparison to other known methods
19. M. Jin, M. Weiming, "Power Converter EMI Analysis Including IGBT Nonlinear Switching Transient Model," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1577-1583, Oct. 2006. Full Text Link
Abstract: It is well known that very high dv/dt and di/dt during the switching instant is the major high-frequency electromagnetic interference (EMI) source. This paper proposes an improved and simplified EMI-modeling method considering the insulated gate bipolar transistor switching-behavior model. The device turn-on and turn-off dynamics are investigated by dividing the nonlinear transition by several stages. The real device switching voltage and current are approximated by piecewise linear lines and expressed using multiple dv/dt and di/dt superposition. The derived EMI spectra suggest that the high-frequency noise is modeled with an acceptable accuracy. The proposed methodology is verified by experimental results using a dc-dc buck converter
20. Z. Kaczmarczyk, "High-Efficiency Class E,$hboxEF_2$, and$hboxE/F_3$Inverters," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1584-1593, Oct. 2006. Full Text Link
Abstract: This paper investigates the new Class EF2 inverter and the already known Class E and E/F3 inverters. The purpose of this paper is to find the answer to the question: what should be added to a classic Class E inverter to improve its performance with minimum expenditure? Class EF2 and E/F3 inverters meet this requirement through operating under zero-voltage switching and zero-voltage slope switching conditions (as in Class E) with improved transistor waveforms (as in Class F and 1/F). Selected results of a numerical analysis of Class E, EF2 and E/F3 inverters are shown and discussed. The analysis is aimed at maximizing the power output capabilities of these inverters for soft-switching conditions and fixed voltage and current stresses on their transistors as constraints. Measurement results of the Class EF2 and E inverters are given to verify the validity of the presented theory. The measured output power of the inverters was 526 and 366 W with the total efficiency of 97.1% and 96.6% at 1 MHz, respectively
21. Q.-C. Zhong, J. Liang, G. Weiss, C.M. Feng, T.C. Green, "$H^infty$Control of the Neutral Point in Four-Wire Three-Phase DC–AC Converters," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1594-1602, Oct. 2006. Full Text Link
Abstract: Inverters used as the interface for a distributed generator in a three-phase four-wire system sometimes operate with a large neutral current because of unbalanced loads and single-phase (possibly nonlinear) loads. Voltage balance within the dc-link of the inverter is important for proper operation of the inverter, and the neutral current is a significant disturbance to this. It is preferable to use fast acting control rather than dissipative balancing or large-valued capacitors. This paper develops a linear model of an actively balanced split dc-link and applies Hinfin control design to provide high-bandwidth robust control. The approach is developed for a conventional two-level inverter, but it remains valid (without change) for a three-level neutral-point clamped inverter. The controller achieves very small deviations of the neutral point (better than 0.5 in 800 V) from the midpoint of the dc source despite the large neutral current (32 ARMS). The controller design is described and verified first in a PSCAD simulation and second in experimental testing of a 30-kW 415-V (line) inverter
22. D. Vilathgamuwa, H.M. Wijekoon, S.S. Choi, "A Novel Technique to Compensate Voltage Sags in Multiline Distribution System—The Interline Dynamic Voltage Restorer," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1603-1611, Oct. 2006. Full Text Link
Abstract: The dynamic voltage restorer (DVR) provides a technically advanced and economical solution to voltage-sag problem. As the voltage-restoration process involves real-power injection into the distribution system, the capability of a particular DVR topology, especially for compensating long-duration voltage sags, depends on the energy storage capacity of the DVR. The interline DVR (IDVR) proposed in this paper provides a way to replenish dc-link energy storage dynamically. The IDVR consists of several DVRs connected to different distribution feeders in the power system. The DVRs in the IDVR system share a common energy storage. When one of the DVR compensates for voltage sag appearing in that feeder, the other DVRs replenish the energy in the common dc-link dynamically. Thus, one DVR in the IDVR system works in voltage-sag compensation mode while the other DVRs in the IDVR system operate in power-flow control mode. In principle, IDVR can operate effectively when constituent DVRs are electrically (not necessarily physically) far apart. Closed-loop load voltage and current-mode-control techniques are used as the control strategy in the two modes of operation. Experimental results obtained for a laboratory prototype of the IDVR are presented to show the effectiveness and the efficacy of the proposed IDVR system to improve power quality
23. D. Alexa, A. Sirbu, A. Lazar, "Three-Phase Rectifier With Near Sinusoidal Input Currents and Capacitors Connected on the AC Side," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1612-1620, Oct. 2006. Full Text Link
Abstract: An analysis of a three-phase low-harmonic diode rectifier equipped with inductors, capacitors connected on the ac side, and diodes is presented. Inductors and capacitors are used in conjunction with the three-phase diode bridge rectifier to improve the waveform of the currents drawn from the utility grid. The operation of the proposed converter is analyzed, and on this basis, design considerations are commented. The converter characteristics are determined as a function of the load current. Comparisons between the studied converter and other rectifiers (classical rectifiers with passive or active filters, three-phase rectifiers with near sinusoidal input currents and capacitors connected on the dc side, and three-phase low-harmonic rectifiers applying the third harmonic current injection) are also presented. Several possible applications of the two variants of the three-phase rectifiers with near sinusoidal input currents (with capacitors connected on the dc side or on the ac side) are mentioned. Analytically derived results are experimentally verified
24. B.-R. Lin, C.-H. Huang, "Implementation of a Three-Phase Capacitor-Clamped Active Power Filter Under Unbalanced Condition," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1621-1630, Oct. 2006. Full Text Link
Abstract: A capacitor-clamped voltage-source inverter for active power filter operation under balanced and unbalanced conditions is proposed to suppress current harmonics and compensate the reactive power generated from the nonlinear loads. The adopted voltage-source inverter is based on a three-level capacitor-clamped topology to reduce the voltage stress of power semiconductors. Two control loops are used in the control scheme to achieve harmonic and reactive currents compensation and to regulate the inverter dc side voltage. In the adopted inverter, the neutral point voltage is compensated by a voltage compensator to obtain the balanced capacitor voltages on the dc side. In order to control the flying capacitor voltages, two redundant states in each inverter leg can be selected to compensate the flying capacitor to obtain a better voltage waveform with low harmonic contents on the ac terminals. The balanced and sinusoidal line currents are drawn from the ac source under the balanced and unbalanced conditions. The feasibility of the proposed scheme is confirmed through experimental results
25. A.K. Gupta, A.M. Khambadkone, "A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1631-1639, Oct. 2006. Full Text Link
Abstract: Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulsewidth modulation (SVPWM) is widely used. However, the implementation of the SVPWM for a multilevel inverter is complicated. The complexity is due to the difficulty in determining the location of the reference vector, the calculation of on-times, and the determination and selection of switching states. This paper proposes a general SVPWM algorithm for multilevel inverters based on standard two-level SVPWM. Since the proposed multilevel SVPWM method uses two-level modulation to calculate the on-times, the computation of on-times for an n-level inverter becomes easier. The proposed method uses a simple mapping to achieve the SVPWM for a multilevel inverter. A general n-level implementation is explained, and experimental results are given for three-level and five-level inverters
26. I. Etxeberria-Otadui, A. Lopez De Heredia, H. Gaztanaga, S. Bacha, M.R. Reyero, "A Single Synchronous Frame Hybrid (SSFH) Multifrequency Controller for Power Active Filters," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1640-1648, Oct. 2006. Full Text Link
Abstract: Conventional integration-based controllers, such as the multisynchronous PI and the multiresonant controllers, are well adapted for multifrequency-current-control applications. The first controller involves multiple reference frames, while the second one operates in a static frame using multiple resonant regulators. This paper presents a hybrid type of controller, called a single synchronous frame hybrid (SSFH) controller, which combines both features: It operates in an SSF mixing conventional PI and resonant controllers. A detailed design criterion for the SSFH controller is presented based on a frequency-response approach. Digital-implementation aspects (such as computation delays) and the phase margin of the system are taken into consideration during the design process. The SSFH and the multiresonant controllers are compared considering various criteria such as the computational load and the performances in terms of transient and steady-state response. It is concluded that the SSFH controller is a very interesting and execution time-saving structure for heavily distorted multifrequency applications, which is especially adapted for balanced or slightly unbalanced cases
27. T. Nussbaumer, M.L. Heldwein, J.W. Kolar, "Differential Mode Input Filter Design for a Three-Phase Buck-Type PWM Rectifier Based on Modeling of the EMC Test Receiver," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1649-1661, Oct. 2006. Full Text Link
Abstract: For a three-phase buck-type pulsewidth modulation rectifier input stage of a high-power telecommunications power supply module, a differential-mode (DM) electromagnetic compatibility (EMC) filter is designed for compliance to CISPR 22 Class B in the frequency range of 150 kHz-30 MHz. The design is based on a harmonic analysis of the rectifier input current and a mathematical model of the measurement procedure including the line impedance stabilization network (LISN) and the test receiver. Guidelines for a successful filter design are given, and components for a 5-kW rectifier prototype are selected. Furthermore, formulas for the estimation of the quasi-peak detector output based on the LISN output voltage spectrum are provided. The damping of filter resonances is optimized for a given attenuation in order to facilitate a higher stability margin for system control. Furthermore, the dependence of the filter input and output impedances and the attenuation characteristic on the inner mains impedance are discussed. As experimentally verified by using a three-phase common-/Differential-Mode separator, this procedure allows accurate prediction of the converter DM conducted emission levels and therefore could be employed in the design process of the rectifier system to ensure compliance to relevant EMC standards
Signal Processing And Control
28. B. Hredzak, G. Guo, J. Zhang, "New Method for Sensorless Measurement of Hard Disk Drives Imbalance," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1662-1668, Oct. 2006. Full Text Link
Abstract: At present, hard disk drives (HDDs) are balanced using external balancing machine after all the components of the HDD are assembled. Therefore, company's throughput is limited by a number of available balancing machines. Besides, an imbalance is measured only once after assembly, and for this reason, there is no possibility to measure if there is any change in imbalance of the HDD during its operation. New method proposed in this paper makes use of the existing head attached to the rotary actuator and position error signal written on the recording media to measure the value of imbalance of the HDD without the need of a balancing machine or any other additional sensors or components. Furthermore, the method enables to monitor and measure any possible changes in imbalance during the life span of the HDD. The proposed method is also attractive to be used in servo-pack writers where the imbalance has to be measured every time a new set of disks is loaded into the writer. Experimental results prove that the method is effective for the measurement of the imbalance of the HDD
29. K.C. Lee, S. Lee, M.H. Lee, "Worst Case Communication Delay of Real-Time Industrial Switched Ethernet With Multiple Levels," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1669-1676, Oct. 2006. Full Text Link
Abstract: The industrial network, often referred to as fieldbus, becomes an indispensable component for intelligent manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers, numerous fieldbus protocols have been developed. But, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multivendor products. As an alternative to fieldbus, the Ethernet (IEEE 802.3) technology is being adapted to the industrial environment. However, the crucial technical obstacle of Ethernet is its nondeterministic behavior that cannot satisfy the real-time requirements. Recently, the switched Ethernet becomes a very promising alternative for real-time industrial application due to the elimination of uncertainties in Ethernet. This paper focuses on the application of the switched Ethernet with multiple levels (that is, cascade structure with multiple switching hubs) for real-time industrial networking. More specifically, this paper presents an analytical performance evaluation of the switched Ethernet with multiple levels from timing diagram analysis, and experimental evaluation from an experimental testbed of networked control system
30. S. Janardhanan, B. Bandyopadhyay, "Output Feedback Sliding-Mode Control for Uncertain Systems Using Fast Output Sampling Technique," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1677-1682, Oct. 2006. Full Text Link
Abstract: This paper presents a method for achieving quasi-sliding mode for uncertain systems using a fast output sampling control strategy that avoids switching of control and, hence, avoids chattering. This method does not need the system states for feedback as it makes use of only the output samples for designing the controller. Thus, this methodology is more practical and easy to implement. The design technique is illustrated through two numerical examples
31. C.-C. Lee, M.-S. Hwang, I.-E. Liao, "Security Enhancement on a New Authentication Scheme With Anonymity for Wireless Environments," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1683-1687, Oct. 2006. Full Text Link
Abstract: In a paper recently published in the IEEE Transactions on Consumer Electronics, Zhu and Ma proposed a new authentication scheme with anonymity for wireless environments. However, this paper shows that Zhu and Ma's scheme has some security weaknesses. Therefore, in this paper, a slight modification to their scheme is proposed to improve their shortcomings. As a result, the scheme proposed in this paper can enhance the security of Zhu and Ma's scheme. Finally, the performance of this scheme is analyzed. Compared with the Zhu-Ma scheme, this scheme is also simple and efficient
Robotics And Vision
32. S. Katsura, J. Suzuki, K. Ohnishi, "Pushing Operation by Flexible Manipulator Taking Environmental Information Into Account," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1688-1697, Oct. 2006. Full Text Link
Abstract: Vibration suppression in a motion-control system is an important problem in industry applications. Recently, a number of studies about flexible manipulators have been reported. However, there is little published on pushing operation by flexible manipulators. Contact motion to an unknown environment is difficult, because the motion system should recognize the environmental stiffness and adapt to it at the time of collision. This paper proposes a pushing control by a flexible manipulator based on a resonance ratio control. The environmental information is estimated more accurately by using a position sensitive device. The proposed method is composed of three modes: 1) approaching; 2) touching; and 3) pushing. In the approaching mode, the resonance ratio control is applied to suppress the torsional vibration. Compliance control is installed in order to relax an impact force in the touching mode. Finally, a two-step controller is proposed for the pushing mode. In the first step, friction effects are identified by a friction-torque observer. Then, the pushing operation with compensation of the stick-slip friction is controlled based on the identification results in the second step. It is possible to remove an object to a desired position. The experimental results show viability of the proposed method
33. K. Khayati, P. Bigras, L.-A. Dessaint, "A Multistage Position/Force Control for Constrained Robotic Systems With Friction: Joint-Space Decomposition, Linearization, and Multiobjective Observer/Controller Synthesis Using LMI Formalism," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1698-1712, Oct. 2006. Full Text Link
Abstract: A historical review of constrained robot modeling and control strategies is first introduced. Next, a design of a motion/force controller for a constrained servo-robot, which is based on a commonly known modeling structure, is proposed. The contact between the end-effector and the environment is subject to frictional features. Accordingly, the control plant is based on the LuGre friction closed-loop observer. Therefore, new nonlinear position and force input transforms, which are slightly different from classical computed torques, are proposed, combined with a new change of variable. The main purpose of this paper is to establish the stability condition by using the passivity of interconnected linear and nonlinear subplants. From then on, because of this formulation, the authors succeed in designing a full-order dynamic position feedback and an integral force controller that ensure exponential stabilization within an Hinfin multiobjective optimization. These conditions are expressed in terms of linear matrix inequalities. The performances are experimentally validated on a two-degrees-of-freedom robot manipulator acting on a horizontal worktable with friction. The LuGre model estimator exhibits a richer behavior in terms of friction compensation and positioning tracking when experimentally compared to the Karnopp friction compensation. The latter form exhibits poor modeling properties at zero crossings of the velocity
34. T.N. Chang, B. Cheng, P. Sriwilaijaroen, "Motion Control Firmware for High-Speed Robotic Systems," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1713-1722, Oct. 2006. Full Text Link
Abstract: This paper addresses the hardware and software platforms of high-speed robot control systems, which are usually integrated with multimodal sensing, multiaxis motion, and complex algorithmic capabilities. In this paper, robot control is considered from numerical processor chip architecture, board-level features, to software development cycles. Various numerical processors ranging from general purpose processors to digital signal processors are examined. This is followed by a review of the common motion control boards. Cross platform and upward compatible software development are addressed. Finally, an example application of real-time slewing control of a high-speed industrial robot is provided
35. G. Kim, W. Chung, "Tripodal Schematic Control Architecture for Integration of Multi-Functional Indoor Service Robots," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1723-1736, Oct. 2006. Full Text Link
Abstract: This paper discusses a control architecture and a system integration strategy for multifunctional indoor service robot public service robot (PSR) systems. The authors have built three versions of the PSR systems for four target service tasks, which are delivery, patrol, guidance, and floor cleaning. They clarify the requirements of the architecture in their applications, and propose the tripodal schematic control architecture as the solution to the architectural problems. The key idea of proposed architecture is to integrate robot systems using following three frameworks, layered functionality diagram, class diagram, and configuration diagram. The proposed architecture was successfully evaluated and implemented to PSR platforms for their target tasks. Experimental results clearly showed that the developed strategy was useful for developing the autonomous service robots
36. D. Lee, W. Chung, "Discrete-Status-Based Localization for Indoor Service Robots," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1737-1746, Oct. 2006. Full Text Link
Abstract: This paper proposes a new localization strategy for indoor service robots. A mobile robot localization problem is difficult to solve by a single continuous algorithm. Major difficulties include dynamic changes of the real world, various uncertainties, limitation of sensor information, and so forth. To develop a practical localization solution, this paper proposes an integrated localization strategy based on the discrete status of the mobile robot. Uncertainties of navigation are specified and classified into discrete status, and then modeled as a Petri net-based discrete localization system. The proposed algorithm integrates developed computational schemes and robot behaviors with respect to the defined status. Major criteria of status discretization include geometric properties of the environment, existence of dynamic obstacles, and reliability level of the estimated position. An efficient map-matching scheme and a map-building strategy are developed toward practical implementations. This paper focuses on providing a synthesized practical localization method, which can deal with various uncertainties by explicit discretization of robot status. The feasibility of the proposed method is experimentally verified with prototype public service robots in dynamic real environments
Letters To The Editor
37. I. Cervantes, S. Perez-Teniers, "Zero-Voltage-Transition Control for a Class of Resonant Converters," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1747-1749, Oct. 2006. Full Text Link
Abstract: The aim of this letter is to improve operation of a class of resonant converters and take quasi-resonant converters (QRCs) as a benchmark to realize this aim. In particular, a variable pulsewidth control scheme is proposed that ensures soft-switching conditions and reduces conduction losses. The control scheme has the feature of significant improvement of efficiency and wider voltage conversion ratio. The proposed controller modifies the pulsewidth of the square driving signal without modifying its frequency. This fact makes it able to be used as a complementary control action to voltage regulators. Results are illustrated via experimental work for the case of a boost-type zero-voltage-switching QRC
38. M.J. Meco-Gutierrez, F. Perez-Hidalgo, F. Vargas-Merino, J.R. Heredia-Larrubia, "A New PWM Technique Frequency Regulated Carrier for Induction Motors Supply," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1750-1754, Oct. 2006. Full Text Link
Abstract: A new generated pulsewidth modulation (PWM) technique is presented herein, making it possible to significantly reduce harmonics in comparison to other common real-time PWMs. This reduction means that a motor connected to an inverter driven by this technique will undergo less overheating and vibrations, thereby improving its performance
39. M.A. Dalla Costa, R.N. Do Prado, "Lamp Improved Arrangement in the Half-Bridge Topology," IEEE Trans. on Industrial Electronics, vol. 53, no. 5, pp. 1754-1756, Oct. 2006. Full Text Link
Abstract: This letter presents a fluorescent-lamp improved arrangement in the half-bridge topology, putting one lamp in each branch of the converter. This arrangement allows a multilamp independent behavior. So, if one lamp is damaged, the other one keeps on working. In order to prove this independent arrangement, experimental results of one electronic ballast supplying two lamps with different wattage were shown