IEEE Transactions on Industrial Electronics

Volume 55, Number 8, August 2008 Access to the journal on IEEE XPLORE IE Transactions Home Page

Special Section Papers

55.8.1	"Table of Contents," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. C1-2841, August 2008. Abstract Link Full Text Abstract: Not Available
55.8.2	"IEEE Transactions on Industrial Electronics publication information," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. C2-C2, August 2008. Abstract Link Full Text Abstract: Not Available
55.8.3	J. M. Guerrero, J. Uceda, "Guest Editorial," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2842-2844, August 2008. Abstract Link Full Text Abstract: The 21 papers in this special section focus on uninterruptible power supply (UPS) systems. They are organized according to the following six topics: control of parallel UPS systems; UPS inverter control; double-conversion UPS; line-interactive UPS; battery management; and dynamic UPC. The papers are summarized here.
55.8.4	J.M. Guerrero, L. Hang, J. Uceda, "Control of Distributed Uninterruptible Power Supply Systems," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2845-2859, August 2008. Abstract Link Full Text Abstract: In the last years, the use of distributed uninterruptible power supply (UPS) systems has been growing into the market, becoming an alternative to large conventional UPS systems. In addition, with the increasing interest in renewable energy integration and distributed generation, distributed UPS systems can be a suitable solution for storage energy in micro grids. This paper depicts the most important control schemes for the parallel operation of UPS systems. Active load-sharing techniques and droop control approaches are described. The recent improvements and variants of these control techniques are presented.
55.8.5	Zhongyi He, Yan Xing, "Distributed Control for UPS Modules in Parallel Operation With RMS Voltage Regulation," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2860-2869, August 2008. Abstract Link Full Text Abstract: A novel distributed control for uninterruptible power supply (UPS) modules in parallel operation is proposed in this paper, in which the voltage reference synchronization control and load current distribution control are decoupled by a local feedback. The voltage reference is presynchronized beyond the current distribution control with a microcontroller unit and a wired-and circuit. Both instantaneous current distribution and hot swapping of any module are allowed with all the UPS modules electrically isolated. The transfer function of the circulating current regulator is analyzed and equivalent to a first-order low-pass filter. The control characteristics of the root-mean-square voltage regulator (RMSVR) in each UPS module in parallel operation are researched, as well as the coupling effect between the RMSVR and the load balance performance. The RMSVR's impact on current distribution is compensated by introducing the amplitude of the output current or the circulating current into the amplitude adjustment of the sinusoidal voltage reference signal. As a result, both the current sharing and the output-voltage performance of the whole system are effectively improved. Theoretical analysis and experimental results are provided to demonstrate the validity and feasibility of the proposed control.
55.8.6	M. Pascual, G. Garcera, E. Figueres, F. Gonzalez-Espin, "Robust Model-Following Control of Parallel UPS Single-Phase Inverters," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2870-2883, August 2008. Abstract Link Full Text Abstract: This paper presents a robust control technique applied to modular uninterruptible power-supply (UPS) inverters operating in parallel. When compared to conventional proportional–integral (PI) control, the proposed technique improves the response of the output voltage to load steps and to high distorted output currents, reducing the distortion of the output voltage. Furthermore, an excellent distribution of currents between modules is achieved, resulting in fine power equalization between the inverters on stream. The crossover frequency of the different loop gains involved is moderate, so that robustness to variations of the operation point and to modeling uncertainties is achieved. A comparative study with a two-loop conventional PI control scheme is presented. Experimental results on a 1-kVA modular online UPS system confirm the viability of the proposed scheme.
55.8.7	Kay-Soon Low, Runzi Cao, "Model Predictive Control of Parallel-Connected Inverters for Uninterruptible Power Supplies," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2884-2893, August 2008. Abstract Link Full Text Abstract: Uninterruptible power supplies (UPSs) have been used in many installations for critical loads that cannot afford power failure or surge during operation. It is often difficult to upgrade the UPS system as the load grows over time. Due to lower cost and maintenance, as well as ease of increasing system capacity, the parallel operation of modularized small-power UPS has attracted much attention in recent years. In this paper, a new scheme for parallel operation of inverters is introduced. A multiple-input–multiple-output state-space model is developed to describe the parallel-connected inverters system, and a model-predictive-control scheme suitable for paralleled inverters control is proposed. In this algorithm, the control objectives of voltage tracking and current sharing are formulated using a weighted cost function. The effectiveness and the hot-swap capability of the proposed parallel-connected inverters system have been verified with experimental results.
55.8.8	Lihua Li, Taotao Jin, K.M. Smedley, "A New Analog Controller for Three-Phase Voltage Generation Inverter," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2894-2902, August 2008. Abstract Link Full Text Abstract: This paper introduces a new controller for a threephase inverter, with a control goal of generating desired threephase output voltages. The proposed controller employs a circuit-level decoupling method, and it is implemented by logic circuitry in combination with a control core and a feedback signal processor. Almost all DC-DC controllers can be adapted as the control core, whereas the feedback signal processor can be implemented by either voltage compensator and/or current compensator. The controller's implementation is simple and flexible with logic and analog circuitry. Yet, it demonstrates experimentally excellent load handling, source voltage noise rejection, and reference tracking ability. The prototype is tested under resistive load, highly nonlinear load, and extreme load transients; aside from that, it is also tested under noisy source voltage and sudden reference change. In all cases, the prototype demonstrated high-quality output voltages.
55.8.9	P. Mattavelli, F. Polo, F. Dal Lago, S. Saggini, "Analysis of Control-Delay Reduction for the Improvement of UPS Voltage-Loop Bandwidth," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2903-2911, August 2008. Abstract Link Full Text Abstract: This paper investigates the effects of control-delay minimization in the dynamic performance of the output stage of uninterruptible power supplies (UPSs) by shifting the sampling time of inductor current and output voltage toward the duty-cycle update instant. This paper shows how a small shift of the output-voltage sampling can significantly increase the UPS voltage-loop bandwidth while keeping the same stability margin. Instead, less contribution comes from the delay minimization of the inductor-current sampling, so that current-ripple cancellation techniques are not needed. A detailed model based on the modified $Z$ -transform, which accounts for different time delays in multiloop control, is proposed. The effectiveness of the proposed analysis is demonstrated by simulation and experimental results on a typical industrial three-phase/three-phase 8-kHz 30-$hbox{kVA}$ UPS prototype. By using two control designs based on the same phase margin, the output-voltage total harmonic distortion with the normalized distorting load is reduced from 6.8% to 5.7%, using a delay of the output voltage sampling equal to 25 $muhbox{s}$.
55.8.10	S. Dalapati, C. Chakraborty, "A Direct PWM Technique for a Single-Phase Full-Bridge Inverter Through Controlled Capacitor Charging," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2912-2922, August 2008. Abstract Link Full Text Abstract: The controlled-capacitor-charging (CCC) technique is utilized in this paper to synthesize a sinusoidal voltage at the output from the unregulated dc at the input. The method is based on the controlled charging/discharging of a capacitor to realize the desired voltage waveform. A capacitor that is connected across the load is charged/discharged through an inductor by applying high-frequency pulses. The applied pulses could be of either positive or negative polarity, depending on the error signal in the controller. The controller senses the output voltage and current and operates to maintain zero-current switching at every turn-on while keeping the output voltage close to the reference waveform by a tracking-control algorithm, enforcing limits in maximum switching frequency and voltage ripples. This paper presents a direct method of implementing the pulsewidth modulation for the single-phase full-bridge inverter, using the CCC technique. A simple procedure to design such an inverter is also discussed. The proposed controller is simulated in a personal computer simulation program with integrated circuit emphasis. Supporting results from an experimental prototype confirm the usefulness of the proposed controller. The inverter may be used in uninterruptible power supply and many other applications.
55.8.11	R. M. Santos Filho, P. F. Seixas, P. C. Cortizo, L. A. B. Torres, A. F. Souza, "Comparison of Three Single-Phase PLL Algorithms for UPS Applications," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2923-2932, August 2008. Abstract Link Full Text Abstract: In this paper, the performance assessment of three software single-phase phase-locked loop (PLL) algorithms is carried out by means of dynamic analysis and experimental results. Several line disturbances such as phase-angle jump, voltage sag, frequency step, and harmonics are generated by a DSP together with a D/A converter and applied to each PLL. The actual minus the estimated phase-angle values are displayed, providing a refined method for performance evaluation and comparison. Guidelines for parameters adjustments are also presented. In addition, practical implementation issues such as computational delay effects, ride-through, and computational load are addressed. The developed models proved to accurately represent the PLLs under real test conditions.
55.8.12	Eung-Ho Kim, Jung-Min Kwon, Jae-Kyu Park, Bong-Hwan Kwon, "Practical Control Implementation of a Three- to Single-Phase Online UPS," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2933-2942, August 2008. Abstract Link Full Text Abstract: A high-performance three- to single-phase online uninterruptible power supply (UPS) is proposed. The proposed UPS is composed of a rectifier, a battery charger/discharger, and an inverter. The rectifier has the capability of power-factor correction and regulates a dc-link voltage. When the rectifier becomes unavailable or when the current required by the load exceeds the output rating of the rectifier, the charger/discharger supplies the power demanded by the load to a dc-link capacitor. The inverter provides a regulated sinusoidal output voltage and limits an output current under an impulsive load. New control algorithms of the rectifier, the charger/discharger, and the inverter are proposed. The proposed algorithms of the rectifier and the charger/discharger improve dynamic performance at step load change. To improve the transient response of the output voltage at outage of an input source, a mode change method of the charger/discharger is also proposed. Additionally, the proposed current-limit algorithm of the inverter can be implemented without additional hardware, and it increases the reliability of the UPS.
55.8.13	J.-K. Park, J.-M. Kwon, E.-H. Kim, B.-H. Kwon, "High-Performance Transformerless Online UPS," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2943-2953, August 2008. Abstract Link Full Text Abstract: In this paper, a high-performance single-phase transformerless online uninterruptible power supply (UPS) is proposed. The proposed UPS is composed of a four-leg-type converter, which operates as a rectifier, a battery charger/discharger, and an inverter. The rectifier has the capability of power-factor collection and regulates a constant dc-link voltage. The battery charger/discharger eliminates the need for the transformer and the increase of the number of battery and supplies the power demanded by the load to the dc-link capacitor in the event of the input-power failure or abrupt decrease of the input voltage. The inverter provides a regulated sinusoidal output voltage to the load and limits the output current under an impulsive load. The control of the dc-link voltage enhances the transient response of the output voltage and the utilization of the input power. By utilizing the battery charger/discharger, the overall efficiency of the system is improved, and the size, weight, and cost of the system are significantly reduced. Experimental results obtained with a 3-kVA prototype show a normal efficiency of over 95.6% and an input power factor of over 99.7%.
55.8.14	N. Vazquez, J. Villegas-Saucillo, C. Hernandez, E. Rodriguez, J. Arau, "Two-Stage Uninterruptible Power Supply With High Power Factor," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2954-2962, August 2008. Abstract Link Full Text Abstract: An uninterruptible power supply (UPS) with high power factor and two conversion stages is suggested. The double-conversion configuration has three stages, but normally, only two stages are operating at the same time. The first stage of the proposed scheme integrates the power-factor-correction stage and the battery charger of the double-conversion configuration, obtaining a two-stage UPS. The second stage is based on the theory of inverter with boosting capabilities. The battery set has not only been completely isolated, but it has also been charged with a small change at the controller set point; these particular characteristics facilitate the system maintenance and simplify its operation. Additionally, the battery-set voltage is low, reducing the weight and size. The converter operation, analysis, design, and experimental results are shown. The proposed UPS approach is practical in low-power applications ($leq 500$ W).
55.8.15	E. Rodriguez, N. Vazquez, C. Hernandez, J. Correa, "A Novel AC UPS With High Power Factor and Fast Dynamic Response," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2963-2973, August 2008. Abstract Link Full Text Abstract: This paper presents a novel ac uninterruptible-power-system (UPS) scheme with high power factor, which offers excellent characteristics such as sinusoidal input current, sinusoidal output voltage, fast regulation of the ac mains, galvanic isolation, and fast transient response. The proposed converter includes the offline–online concept, which avoids the continuous charging and discharging of the battery as it occurs in a typical online UPS. Analysis and design considerations, as well as simulation and experimental results, are given in this paper.
55.8.16	C. G. C. Branco, C. M. T. Cruz, R. P. Torrico-Bascope, F. L. M. Antunes, "A Nonisolated Single-Phase UPS Topology With 110-V/220-V Input–Output Voltage Ratings," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2974-2983, August 2008. Abstract Link Full Text Abstract: A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type of configuration size, cost and efficiency are improved due to the reduced number of switches and batteries, and also, no low-frequency isolation transformer is required to realize bypass operation because of the common neutral connection. Both stages of the proposed circuit operate at high frequency by using a passive nondissipative snubber circuit in the boost converter and insulated-gate bipolar-transistor switches in the double half-bridge inverter, with low conduction losses, low tail current, and low switching losses. Principle of operation and experimental results for a 2.6-kVA prototype are presented to demonstrate the UPS performance.
55.8.17	R. P. Torrico-Bascope, D. S. OliveiraJr., C. G. C. Branco, F. L. M. Antunes, "A UPS With 110-V/220-V Input Voltage and High-Frequency Transformer Isolation," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2984-2996, August 2008. Abstract Link Full Text Abstract: This paper proposes an isolated double-conversion uninterruptible power system with power factor correction using a high-frequency transformer and with input voltages equal to 110 V/220 V. The arrangement is suitable to rack-type structures because it has a small size and a reduced weight. For both input voltages, the proposed converter has almost the same efficiency processing the same output power. Other relevant features include soft commutation of the controlled switches in the chopper and boost stages, a simple control strategy that can be implemented with well-known integrated circuits, and the use of few batteries in series due to the step-up stage. Qualitative analysis and experimental results obtained with a 2-kVA prototype show a normal efficiency of over 86% for the worst case of input voltage and an input power factor of over 99%.
55.8.18	Zhi Jian Zhou, Xing Zhang, Po Xu, W.X. Shen, "Single-Phase Uninterruptible Power Supply Based on Z-Source Inverter," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 2997-3004, August 2008. Abstract Link Full Text Abstract: This paper presents a new topology of uninterruptible power supply (UPS) by using a Z-source inverter, where a symmetrical LC network is employed to couple the main power circuit of an inverter to a battery bank. With this new topology, the proposed UPS can maintain the desired ac output voltage at the significant voltage drop of the battery bank with high efficiency, low harmonics, fast response, and good steady-state performance in comparison with traditional UPSs. The simulation and experimental results of a 3-kW UPS with the new topology confirm its validity.
55.8.19	M.A.P. de Azpeitia, A. Fernandez, D.G. Lamar, M. Rodriguez, M.M. Hernando, "Simplified Voltage-Sag Filler for Line-Interactive Uninterruptible Power Supplies," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3005-3011, August 2008. Abstract Link Full Text Abstract: There are three types of static uninterruptible power supplies (UPSs): passive standby, line interactive, and double conversion. The last one protects the load against all types of line disturbances, but it is the most expensive and the one with the lowest efficiency. On the other hand, passive-standby and line-interactive UPSs have higher efficiency and lower cost, but they show an important drawback: a switching time from normal to stored-energy mode. As a consequence, there is a notch in the UPS output voltage during this switching time. In a previous paper, the authors proposed a method for filling these voltage notches with a sinusoidal waveform generated by a switch-mode converter. In this one, a simplified notch filler is proposed. It consists of two capacitors, one charged with positive voltage and the other with negative voltage. If the fault occurs in the positive period, the positive-charged capacitor is connected to the load. This connection is then modulated in order to obtain a sinusoidal waveform at the load. In the negative period, the other capacitor is used in the same way.
55.8.20	Haimin Tao, J.L. Duarte, M.A.M. Hendrix, "Line-Interactive UPS Using a Fuel Cell as the Primary Source," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3012-3021, August 2008. Abstract Link Full Text Abstract: This paper proposes a line-interactive fuel-cell-powered uninterruptible-power-supply system. A three-port bidirectional converter connects a fuel cell and a supercapacitor to a grid-interfacing inverter. The system can operate in both stand-alone and grid-connected modes. Moreover, an active filtering function is integrated into the system. It is shown that a supercapacitor can serve as both an active and a reactive energy storage and can buffer the periodical low-frequency ripple in the requested power. For connecting the system to the utility grid, a high-performance single-phase phase-locked loop that incorporates an orthogonal filter is presented. Resonant controllers for both the voltage and current regulations eliminate steady-state error and implement selective harmonic compensation. Simulation and experimental results are provided to show the feasibility of the proposed system and the effectiveness of the control methods.
55.8.21	Liang-Rui Chen, Neng-Yi Chu, Chau-Shing Wang, Ruey-Hsun Liang, "Design of a Reflex-Based Bidirectional Converter With the Energy Recovery Function," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3022-3029, August 2008. Abstract Link Full Text Abstract: In this paper, a reflex charging strategy with the energy recovery function for a bidirectional converter (BC) is proposed to build a novel reflex-based BC (RBC) for increasing the battery charging efficiency in an uninterruptible power supply (UPS). The proposed RBC can provide a reflex charging current profile to charge the battery to obtain a high battery charging efficiency and prolong the battery life cycle. In particular, the negative pulse energy of the reflex charging current profile in the proposed RBC is recovered to reduce the battery charging dissipation. A soft transfer method is also developed in this paper to really erase the spike current in the RBC. A 400 W prototype is designed and implemented to verify the feasibility of the proposed RBC. Compared with a typical bidirectional converter, the battery charging efficiency, the battery charging speed, and the battery thermal deterioration effect are improved by about 10%, 8.8%, and 7%, respectively, with the proposed RBC.
55.8.22	Ying-Chun Chuang, Yu-Lung Ke, "High-Efficiency and Low-Stress ZVT–PWM DC-to-DC Converter for Battery Charger," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3030-3037, August 2008. Abstract Link Full Text Abstract: This work presents a novel highly efficient and low-stress battery charger with a resonant switch converter—based on resonance and zero-voltage-transition soft-switching theory—that reduces defects associated with high voltage and high current stresses caused by the resonance of traditional resonant circuits. The novel battery charger meets the requirement that all circuit components must operate with zero-voltage switching. Experimental test results indicate that the proposed battery charger reduces the temperature of an active power switch, and switching losses are less than those obtained using a traditional pulsewidth-modulation converter as a battery charger.
55.8.23	Jae-Do Park, C. Kalev, H.F. Hofmann, "Control of High-Speed Solid-Rotor Synchronous Reluctance Motor/Generator for Flywheel-Based Uninterruptible Power Supplies," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3038-3046, August 2008. Abstract Link Full Text Abstract: A hybrid controller, consisting of a model-based feedforward controller and a proportional–integral feedback compensator, for a solid-rotor synchronous reluctance motor/generator in a high-speed flywheel-based uninterruptible power supply application is proposed in this paper. The feedforward controller takes most of the control output of the current regulator based on the machine model, and the PI controllers compensate the possible inaccuracies of the model to improve the performance and robustness of the complete control system. The machine current tracking error caused by parameter inaccuracy in the model-based controller is mathematically analyzed and utilized to dynamically compensate the estimated flux linkage to eliminate the steady-state error in current regulation. Stability analysis is also presented, and it can be seen that the regulation performance and robustness of the system are improved by the proposed hybrid controller. Simulation and experimental results consisting of a flywheel energy storage system validates the performance of the controller.
55.8.24	G. Iwanski, W. Koczara, "DFIG-Based Power Generation System With UPS Function for Variable-Speed Applications," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3047-3054, August 2008. Abstract Link Full Text Abstract: The power generation system with a doubly fed induction generator (DFIG), which can be used as an autonomous power system after the loss of mains in a distributed generation network, is described. After the mains outage, a fixed frequency and an amplitude of the output voltage are obtained, despite the variable rotor speed. For this reason, it can be successfully applied in the variable-speed wind turbines, adjustable speed water plants, or diesel engines. Moreover, the stand-alone operation of DFIG is useful in a flywheel-based high-energy rotary uninterruptible power supply system. An output voltage is controlled directly by the synchronization of an actual voltage vector with the reference vector represented in a synchronously rotating polar frame. The rotor current angular speed is obtained as a result of vectorial phase-locked loop operation. Any sensors or estimators of the rotor speed or position are unnecessary. Both amplitude and angle control loops are linear. The use of stand-alone operation in grid-connected systems requires mains outage detection. Also, the grid voltage recovery requires a method of synchronization and soft connection of a generator to the grid. The proposed methods of output voltage control, synchronization, and detection of mains loss were tested in a laboratory system. Single-Phase Electronics
55.8.25	E. Adib, H. Farzanehfard, "Family of Zero-Current Transition PWM Converters," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3055-3063, August 2008. Abstract Link Full Text Abstract: In this paper, a new auxiliary circuit is introduced for applying to buck, buck-boost, zeta, forward, and flyback converters. This auxiliary circuit provides a zero-current switching condition for all switching elements. The proposed zero-current transition (ZCT) pulsewidth-modulated buck converter is briefly described. Also, a ZCT flyback converter is analyzed, and its different operating modes are presented. Design considerations are explained, and a design example along with the experimental results of the ZCT flyback converter is presented.
55.8.26	A. Fernandez, J. Sebastian, M.M. Hernando, D.G. Lamar, M.A. Perez de Azpeitia, M. Rodriguez, "Modeling of an AC-to-DC Converter With a Single-Stage Power Factor Corrector," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3064-3076, August 2008. Abstract Link Full Text Abstract: For years, many authors have done new proposals about the use of single-stage solutions to meet IEC 61000-3-2 regulations. These kinds of topologies can reduce the harmonic content without excessively penalizing the efficiency of the converter. Furthermore, although they are called single-stage topologies, actually, they are not exactly single-stage converters because a part of the energy is processed twice. As a consequence, the small-signal model is not evident at all because the energy flow in the converter is quite complex. This paper deals with the dynamic model of a half-bridge converter with an active input current shaper. Both a small-signal model and a large-signal model have been obtained, and the results were compared with those of a real prototype. The experimental results of the dynamic behavior are also presented.
55.8.27	Lijun Hang, Wenxi Yao, Zhengyu Lu, Zhaoming Qian, J.M. Guerrero, "Analysis of Flux Density Bias and Digital Suppression Strategy for Single-Stage Power Factor Corrector Converter," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3077-3087, August 2008. Abstract Link Full Text Abstract: Single-stage power factor corrector (PFC) ac/dc converter with galvanic isolation is preferable in some industrial applications due to its characteristic of cost-effective and high-power density. However, the transformer used for isolation in such topologies can be easily saturated. In this paper, the generation principle of flux density bias for the transformer involved in the single-stage (SS)-type full-bridge (FB) power factor corrector (PFC) converter is analyzed in detail. The maximum flux density bias during every line period is obtained by recursion. Conventional suppressing strategies of flux density bias are analyzed, and a digital suppressing approach is proposed. A 5 kW SS-FB PFC prototype is built and tested, and the proposed control strategy is implemented by means of a digital signal processor (DSP) board based on the TMS320LF2407A. The feasibility of the proposed approach is well verified through the experimental results. Multiphase Systems
55.8.28	G.P. Adam, S.J. Finney, A.M. Massoud, B.W. Williams, "Capacitor Balance Issues of the Diode-Clamped Multilevel Inverter Operated in a Quasi Two-State Mode," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3088-3099, August 2008. Abstract Link Full Text Abstract: A new operational mode for diode-clamped multilevel inverters termed quasi two-level operation is proposed. Such operation aims to avoid the imbalance problem of the dc-link capacitors for multilevel inverters with more than three levels and reduces the dc-link capacitance without introducing any significant voltage ripple at the dc-link nodes. The proposed operation can be generalized for any number of levels. The validity of the proposed multilevel inverter operational mode is confirmed by simulations and experiments on a prototype five-level diode-clamped inverter.
55.8.29	J. Andreu, J.M. De Diego, I.M. de Alegria, I. Kortabarria, J.L. Martin, S. Ceballos, "New Protection Circuit for High-Speed Switching and Start-Up of a Practical Matrix Converter," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3100-3114, August 2008. Abstract Link Full Text Abstract: The matrix converter (MC) presents a promising topology that needs to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the market. Taking into consideration that the great majority of efforts are being oriented toward control algorithms and modulation, this paper focuses on MC hardware. In order to improve the switching speed of the MC and thus obtain signals with less harmonic distortion, several different insulated-gate bipolar transistor (IGBT) excitation circuits are being studied. Here, the appropriate topology is selected for the MC, and a recommended configuration is selected, which reduces the excursion range of the drivers, optimizes the switching speed of the IGBTs, and presents high immunity to common-mode voltages in the drivers. Inadequate driver control can lead to the destruction of the MC due to its low ride-through capability. Moreover, this converter is especially sensitive during start-up, as, at that moment, there are high overcurrents and overvoltages. With the aim of finding a solution for starting up the MC, a circuit is presented (separate from the control software), which ensures correct sequencing of supplies, thus avoiding a short circuit between input phases. Moreover, it detects overcurrent, connection/disconnection, and converter supply faults. Faults cause the circuit to protect the MC by switching off all the IGBT drivers without latency. All this operability is guaranteed even when the supply falls below the threshold specified by the manufacturers for the correct operation of the circuits. All these features are demonstrated with experimental results. Lastly, an analysis is made of the interaction that takes place during the start-up of the MC between the input filter, clamp circuit, and the converter. A variation of the clamp circuit and start-up strategy is presented, which minimizes the overcurrents that circulate through the conve- - rter. For all these reasons, it can be said that the techniques described in this paper substantially improve the MC start-up cycle, representing a step forward toward the development of reliable MCs for real applications.
55.8.30	Rong-Tai Chen, "Capacitor-Based Multisource of Flyback-Type Power Collector," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3115-3123, August 2008. Abstract Link Full Text Abstract: This paper presents a multisource power collection method based on electric addition in capacitors for renewable energy application. Instead of combining input sources in magnetic form, the proposed flyback-type collector combines input dc sources in electric form by adding up the electric energy together in the capacitors. With pulsewidth modulation (PWM) control, the proposed collector can draw power from three larger different dc sources and individually and simultaneously deliver it to the battery. The operating principle of the proposed collector with three different input stages has been analyzed in detail. The output voltage regulation and power budget can be achieved by the phase-shifted PWM control. Two prototypes of the collector system with three different dc voltage sources have been successfully implemented to verify the performance of the power collector. Robotics and Mechatronics
55.8.31	M. Chueh, Y.L.W. Au Yeung, K.-P.C. Lei, S.S. Joshi, "Following Controller for Autonomous Mobile Robots Using Behavioral Cues," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3124-3132, August 2008. Abstract Link Full Text Abstract: This paper proposes an autonomous-robot following controller that can integrate information provided from behavioral cues of the leader to increase the reliability and the performance of following. The controller continuously estimates the future predicted position of the leader as it moves, and then directs the follower robot to this position. A Kalman filter is employed for an estimation that uses vision-based measurements of leader position, a dynamic model of the leader, and a behavioral-cue model of the leader. The behavioral-cue model serves to either tune the dynamic model and/or create pseudomeasurements to further help the Kalman filter estimate the leader's future position. Once the leader's future position is estimated, a trajectory planner plans a path to the future position, and a motor controller implements the required control signals to the robot wheels. It is suggested that this controller may have particular importance for human following by autonomous robots in future human-robot interaction environments. Signal Processing and Control
55.8.32	R.H. Abiyev, O. Kaynak, "Fuzzy Wavelet Neural Networks for Identification and Control of Dynamic Plants—A Novel Structure and a Comparative Study," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3133-3140, August 2008. Abstract Link Full Text Abstract: One of the main problems for effective control of an uncertain system is the creation of the proper knowledge base for the control system. In this paper, the integration of fuzzy set theory and wavelet neural networks (WNNs) is proposed to alleviate the problem. The proposed fuzzy WNN is constructed on the base of a set of fuzzy rules. Each rule includes a wavelet function in the consequent part of the rule. The parameter update rules of the system are derived based on the gradient descent method. The structure is tested for the identification and the control of the dynamic plants commonly used in the literature. It is seen that the proposed structure results in a better performance despite its smaller parameter space.
55.8.33	Jiann-Jong Chen, Ho-Cheng Lin, Che-Min Kung, Yuh-Shyan Hwang, Juing-Huei Su, "Integrated Class-D Amplifier With Active Current Sensing Suitable for Alternating Current Switches," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3141-3149, August 2008. Abstract Link Full Text Abstract: An integrated class-D amplifier with active current sensing suitable for ac switches is presented in this paper. The proposed current-sensing technique is used to sense and control the inductor current at the output stage and allows the current-sensing element to be integrated into class-D amplifiers. To verify the performance of the proposed circuits, a class-D amplifier was designed and fabricated with 3.3-V 0.35- $muhbox{m}$ double-polyquadruple-metal CMOS technology on a chip area of 1.79 $times$ 1.45 mm. The maximum power efficiency of the class-D amplifier can be up to 94% for an 8-$Omega$ load. These active current-sensing circuits can be applied to other power converters with ac switches.
55.8.34	G. Escobar, P.G. Hernandez-Briones, P.R. Martinez, M. Hernandez-Gomez, R.E. Torres-Olguin, "A Repetitive-Based Controller for the Compensation of $6ellpm 1$ Harmonic Components," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3150-3158, August 2008. Abstract Link Full Text Abstract: In this paper, a repetitive-based controller for the compensation of $6ell pm 1$ harmonic components is proposed. This control scheme is more appropriate for processes that involve the use of six-pulse converters or other converters that mainly produce harmonic components at those frequencies. The control scheme is based on the feedback array of two delay lines plus a feedforward path that compensates only the $6ellpm 1$ multiples of the fundamental frequency, thereby reducing the possibility of reinjecting unnecessary distortion into the system. The proposed scheme is, then, plugged into a generic feedback control system where a stability analysis is carried out. In addition, the passivity properties of the proposed scheme are presented, which open the possibility of control design following the passivity-based approach. Experiments that are based on a simple digital implementation are provided to illustrate the merits of our solution. These results include the open-loop responses of the proposed scheme and the responses in a practical example to validate its effectiveness in an application. For this latter result, the proposed scheme has been used in the controller of a 2-kVA shunt active filter to compensate the current harmonic distortion. Emerging Technology
55.8.35	Shen-Yaur Chen, Jin-Jia Chen, "Study of the Effect and Design Criteria of the Input Filter for Buck Converters With Peak Current-Mode Control Using a Novel System Block Diagram," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3159-3166, August 2008. Abstract Link Full Text Abstract: The effect and design criteria of the input filter for buck converters with peak current-mode (PCM) control are researched using a novel system block diagram. With this diagram, a novel current loop transfer function is proposed to derive the design criteria that apply to designing the input filter. However, the input filter that is added to reduce electromagnetic interference will significantly change the dynamic property of the PCM-controlled buck converter. Therefore, the induced effect due to the input filter is examined. Finally, experimental results prove the accuracy of this deduction in both the circuit simulation and the circuit experiment.
55.8.36	D. Gonzalez, J.T. Bialasiewicz, J. Balcells, J. Gago, "Wavelet-Based Performance Evaluation of Power Converters Operating With Modulated Switching Frequency," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. 3167-3176, August 2008. Abstract Link Full Text Abstract: It has been demonstrated that modulating the switching frequency of a power converter is a valuable way for reducing the electromagnetic interference (EMI) due to the switching process. Since we are considering a signal whose frequency content varies with time, wavelets are well suited to analyze the performance of such techniques. In this paper, we evaluate the performance of spread spectrum frequency modulation (SSFM) applied to the EMI reduction of a real power converter that uses periodic pattern switching frequency modulation. The performance of the converter under investigation includes the analysis of the switching voltage spectrum (as the main source of EMI) and the output voltage ripple. This evaluation is performed with two coefficients, i.e., maximum energy ratio (MER) and energy dispersion ratio (EDR), which are figures of merit defined in this paper using time-dependent energy density distribution in frequency, obtained from the scalograms of the analyzed signals. Such figures of merit allow comparison in the time–frequency domain of different modulation techniques and the choice of the best solution for each case in terms of reduction of the peak of noise spectrum.
55.8.37	"IEEE Industrial Electronics Society Information," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. C3-C3, August 2008. Abstract Link Full Text Abstract: Not Available
55.8.38	"IEEE Transactions on Industrial Electronics information for authors," IEEE Trans. on Industrial Electronics, vol. 55, no. 8, pp. C4-C4, August 2008. Abstract Link Full Text Abstract: Not Available