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This paper provides design guidelines for the passive LC filters. Based on these guidelines, a method to design a new type of a passive filter, called hybrid LC filter, is proposed. A filter design example accompanies the considerations; simulation and test results of the proposed filter in time and frequency domains are shown. [ABSTRACT FROM PUBLISHER]

This paper presents a generalized vector control system for a generic brushless doubly fed (induction) machine (BDFM) with nested-loop type rotor. The generic BDFM consists of p1/p2 pole-pair stator windings and a nested-loop rotor with N number of loops per nest. The vector control system is derived based on the basic BDFM equation in the synchronous mode accompanied with an appropriate synchronization approach to the grid. An analysis is performed for the vector control system using the generic BDFM vector model. The analysis proves the efficacy of the proposed approach in BDFM electromagnetic torque and rotor flux control. In fact, in the proposed vector control system, the BDFM torque can be controlled very effectively promising a high-performance BDFM shaft speed control system. A closed-loop shaft speed control system is composed based on the presented vector control system whose performance is examined both in simulations and experiments. The results confirm the high performance of the proposed approach in BDFM shaft speed control as well as a very close agreement between the simulations and experiments. Tests are performed on a 180-frame prototype BDFM. [ABSTRACT FROM PUBLISHER]

This paper deals with multiterminal voltage source converter (VSC) HVDC transmission systems for the connection of offshore wind power plants to the main land ac grid. A droop-based control scheme is considered. The droop controllers have been designed base on a mixed sensitivity criterion by solving a convex optimization problem with linear matrix inequalities. The system is analyzed by means of simulations and experimentally in a scaled platform. Simulations show the control performance during a wind speed change and a voltage sag in the main ac grid. Experimental results include wind power changes (increase and decrease) and an eventual VSC loss (both considering grid-side and wind farm VSC loss). In all the cases, the simulation and the experimental results have shown a good system performance. [ABSTRACT FROM PUBLISHER]

Despite being more efficient, line commutated converter-HVDC links for the connection of large offshore wind farms have ac-filter bank size as one of their main drawbacks. This paper shows how the HVDC rectifier filter banks can be substantially reduced by taking advantage of the additional control possibilities offered by the use of wind turbines with fully rated converters. PSCAD simulations validate wind farm and diode rectifier HVDC link operation with a capacitor and filter bank five times smaller than its usual value. The proposed control algorithm allows for good harmonic and reactive power sharing between the different wind turbines. As the reduced capacitor bank operation leads to a redistribution of harmonic and reactive currents, an efficiency study has been carried out to evaluate the new power loss distribution with the reduced filter banks. [ABSTRACT FROM PUBLISHER]

This paper describes a d– q transformation to be applied to double-star permanent-magnet synchronous machines with interior magnets. The d– q model consists of two d–q reference frames decoupled with respect to each other and applies to a generic angular displacement between the winding sets. The decoupled d–q model simplifies the analysis of the machine behavior and the drive control implementation. Machine parameters are determined by a sequence of finite-element (FE) analyses. The effectiveness of the proposed modeling method is verified by a comparison with the results related to measurements on a test machine and FE simulations. It was assumed that the mutual inductances between the two winding sets can be represented with two coefficients. Although such an assumption inevitably leads to inaccuracy in the machine model, the simulation results with the proposed d–q model agree remarkably well with the experimental results and FE simulations. [ABSTRACT FROM PUBLISHER]

This paper introduces, explains, and investigates the application of a transformerless series-connected reactive/harmonic compensator. The proposed compensator is applied to compensate the high reactive-power/harmonic demand of a 12-pulse line-commutated HVDC rectifier terminal. Simulation results reveal that the proposed strategy compensates the reactive power and harmonics of the HVDC converter satisfactorily. All of this is achieved using significantly smaller capacitance at the compensator dc link than the capacitance required in the state-of-the-art shunt compensators employing passive components. The compensator thus would eliminate the need of fundamental-frequency reactive power supply and minimize (or eliminate altogether) the requirement of passive shunt harmonic compensation. This would result into smaller shunt passive filters, smaller or no shunt capacitor banks, and smaller converter transformers, leading to a more compact HVDC terminal, the current size of which is considered to be the main hurdle in its application for integration of large-scale offshore wind energy. Experimental results from a small-scale setup validate the effectiveness observed in the simulations. [ABSTRACT FROM PUBLISHER]

This paper consists of the presentation of a regulation strategy capable of controlling the energy stored in the modular multilevel converter (MMC) in an HVDC configuration. This is achieved by regulating the positive, negative, and zero sequences in dqo coordinates of the differential current using two rotating reference frames: at once and at twice the fundamental grid frequency value. The active and reactive negative sequence components of the differential current at twice the fundamental frequency are used to eliminate the oscillations of the three-phased leg energy, reducing significantly the capacitor voltage oscillations, while the zero-sequence component is used to regulate the total energy stored at a given reference. Meanwhile, active and reactive positive sequence components of the circulating current are used for eliminating the average energy difference between the upper and lower arms in a three-phase MMC. In order to decouple efficiently the differential current components, the decoupled-double-synchronous-reference-frame current control strategy is used. Finally, simulation results validate the performance of the MMC in an HVDC configuration with the proposed control. Control equations are demonstrated, and cross-coupled leg-energy terms are introduced. [ABSTRACT FROM PUBLISHER]

This paper includes a technical feasibility study on the use of an HVDC diode-based rectifier together with an onshore voltage-source converter (VSC) for the connection of large offshore wind farms. A distributed control algorithm for the wind farm is used, where all the wind turbines contribute to the offshore-grid voltage and frequency control while allowing wind turbine optimal power tracking. Moreover, the proposed system shows good fault ride-through performance to solid faults at the onshore connection point, wind-farm ac grid, and HVDC line. The technical feasibility of the proposed solution has been validated by means of detailed PSCAD/EMTDC simulations. The efficiency of the complete system has also been studied and found to compare favorably with that of a VSC–HVDC-inverter station. [ABSTRACT FROM PUBLISHER]

In this paper, the balance control of a ball and beam system is considered. Based on the T-S fuzzy modeling, the dynamic model of the ball and beam system is formulated as a strict feedback form with modeling errors. Then, an adaptive dynamic surface control (DSC) is utilized to achieve the goal of ball positioning subject to parameter uncertainties. The robust stability of the closed-loop system is preserved by using the Lyapunov theorem. In addition to simulation results, the proposed T-S fuzzy model-based adaptive dynamic surface controller is applied to a real ball and beam system for practical evaluations. Simulation and experimental results illustrate that the proposed control scheme has much better performance than that of conventional DSC. Furthermore, parameter uncertainties and external disturbance are considered to highlight the robustness of the proposed control scheme. [ABSTRACT FROM PUBLISHER]

Fast fault detection and reconfiguration of power converters is necessary in electrical drives to prevent further damage and to make the continuity of service possible. On the other hand, component minimized converters may provide the benefits of higher reliability and less volume and cost. In this paper, a new fault-tolerant converter topology is studied. This converter has five legs before the fault occurrence, and after fault detection the converter continues to function with four legs. A very fast fault detection and reconfiguration scheme is presented and studied. Simulations and experimental tests are performed to evaluate the structure requirements, the digital reconfigurable controller, and fault detection scheme. For experimental tests, the control and the fault detection and reconfiguration schemes are implemented on a single field-programmable gate array (FPGA) chip. Experimental and simulation results show the effectiveness of the proposed fault-tolerant topology and its FPGA-based control. [ABSTRACT FROM PUBLISHER]

A small-scale wind energy conversion system can track the maximum power point (MPP) based on a linear relationship between Vdc^2 and Idc. Unlike conventional MPP tracking (MPPT) methods using a lookup table, an advanced technique is proposed based on this relationship as a variant of the perturb and observe (P&O) method. It not only has the advantages of the conventional P&O method but also has a faster tracking speed and better performance. This paper theoretically analyzes the possible power coefficient drop when using a linear relationship for MPPT and establishes that the turbine design can ensure that the possible power coefficient drop is small. The simulation results show that the analysis is precise. The validity and performance of the proposed MPPT method are confirmed by both simulation and experimentation. [ABSTRACT FROM PUBLISHER]

Model predictive control (MPC) for a two-motor drive, supplied from a five-leg inverter, is presented in this paper. As an alternative to existing methods, use of MPC in multimachine drives has the advantages of independent fast current control of the machines, elimination of the closed-loop system's cascaded structure, and a reduced number of microcontrollers. A vector control algorithm is required, necessitating state-space modeling, with each machine's direct- and quadrature-axis currents chosen as state variables. Prediction of future states is via a discrete-time model of the five-leg inverter and a piecewise-affine model of two permanent-magnet synchronous motors (PMSMs). A method which eliminates unfeasible switching states inherent in reduced-switch-count inverters while reducing computation and sampling times is proposed. The algorithm is implemented in a TMS320F28335 DSP microcontroller, which controls the five-leg inverter and the two PMSMs. Simulation and experimental results validate the presented control concept. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel dual-input matrix converter (DIMC) to integrate two three-phase ac type energy resources to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six-switch voltage source converter replaced by a nine-switch configuration. With the additional three switches, the proposed DIMC can provide six input terminals, which make it possible to integrate two independent ac sources into a single grid-tied power electronics interface. The proposed converter has input-to-output voltage boost capability since power flows from the converter's voltage source side to its current source side. Commanded currents can be extracted from the two input sources to the grid. The proposed control and modulation schemes guarantee sinusoidal input and output waveforms as well as unity input power factors. The simulation and experimental results using a laboratory prototype are provided to validate the effectiveness of the proposed control and modulation schemes for the proposed converter. [ABSTRACT FROM PUBLISHER]

With contactless inductive power transfer (IPT), it is possible to transfer electrical energy to stationary or movable consumers without contacts, cables, or slip rings. To reduce the very high development effort of new contactless inductive energy supplies, a new systematic and modular design methodology is presented in the paper. This methodology includes new methods to increase the transfer efficiency and the positioning flexibility of the consumer device and is particularly implemented into a simulation software tool. The positioning tolerance is improved by the optimization of the coil and ferrite geometry. Thereby, the influence of physical and geometrical parameters on the magnetic coupling and on the electrical transfer characteristics is investigated. As a result of the design methodology, a new IPT system for household appliances in the output power range of 1 kW at an overall efficiency of more than 90% and with a high positioning tolerance is presented. [ABSTRACT FROM PUBLISHER]

Inductive power transfer (IPT) technology is a well-recognized technique for supplying power to a wide range of applications with no physical contacts. With the emergence of applications such as electric vehicles and vehicle-to-grid systems, IPT systems with bidirectional power flow have become a recent focus. In contrast to simple unidirectional IPT systems, bidirectional systems are complex in nature and essentially require more sophisticated and robust control strategies. This paper proposes a new controller, which is based on power–frequency droop characteristics of IPT systems, to regulate its power flow in both directions without a dedicated communication link. The proposed controller is applicable to unidirectional as well as bidirectional IPT systems with either single or multiple loads and ensures that power intake by the load side is always kept within the capability of the supply side. Analysis, together with both experimental and simulated results, of a 1-kW single-load bidirectional IPT system is presented with discussions to show that the proposed droop controller can successfully be used to regulate the two-way power flow. [ABSTRACT FROM PUBLISHER]

Capacitively coupled power transfer (CCPT) technology has been proposed and investigated recently as an alternative contactless power transfer method. A CCPT system has the advantage of being able to transfer power across metal barriers with low standing power losses, so it is potentially good for charging consumer electronics such as mobile phones, laptops, lamps, etc. However, a big challenge in designing a CCPT charging platform is the output voltage of a CCPT power supply varies greatly with the positioning and alignment of the pickup on a charging pad due to the change in power flow. This paper proposes a CCPT charging platform with a matrix charging pad and a dynamically soft switched transformer to control the power flow and regulate the output voltage under variable coupling conditions. The proposed charging platform is verified by simulation and experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, issues related to parameter identification and high-performance control of the drive system with an elastic joint are discussed. After a brief introduction, the mathematical model of the drive and the proposed high-performance control structure are presented. The effect of the location of closed-loop poles and cancellation of zeros of the structure is examined. Then, the mathematical models of the Kalman filters used in this study are presented, and the results of the identification procedure are described. The effectiveness of the proposed structure has been examined under simulation and experimental study. [ABSTRACT FROM PUBLISHER]

This paper presents a novel method by the multilevel analysis (MLA) to estimate the composition rate of electric loads with respect to measured total current waveform by improving the performance of a previous estimation scheme proposed by the authors. The proposed MLA makes it possible to analyze the electric load composition rate (LCR), which indicates the portions of several typical loads connected to a single point of common coupling (PCC), with the partition of several levels. Then, the Kalman-filter (KF) algorithm is applied to solve the estimation problem of LCR based on formulation with current waveforms in each level. The effectiveness of MLA based on the KF in practice is verified by the experimental implementation based on the prototype's setup in laboratory. It consists of a 3-kW photovoltaic grid-connected inverter, which contributes to a small distortion in voltage at PCC, and practical nonlinear loads connected to PCC. Also, the harmonic-current-injection-model-based time-domain simulations are carried out to prove the potential of the proposed method under various circumstances with different nonlinear loads. [ABSTRACT FROM PUBLISHER]

This paper presents a nonlinear optimal speed controller based on a state-dependent Riccati equation (SDRE) for permanent magnet synchronous motor (PMSM). An SDRE-based near optimal load torque observer is also proposed to provide the load torque information for the controller. In both designs, the stability is analytically proven, and the Taylor series method is used to find an approximate solution because the SDRE cannot be directly solved. The SDRE-based optimal controller and the observer can ensure better control performance such as no overshoot and fast transient response in speed tracking than the linear conventional controllers such as linear quadratic regulator and proportional–integral controller even under the variations of the model parameters and load torque. The proposed SDRE-based control strategy is implemented on a PMSM testbed using TMS320F28335 DSP. The simulation and experimental results are given to prove the feasibility of the proposed control scheme. [ABSTRACT FROM PUBLISHER]

In this paper, the use of extended Kalman filter for the optimization of the parameters of type-2 fuzzy logic systems is proposed. The type-2 fuzzy logic system considered in this study benefits from a novel type-2 fuzzy membership function which has certain values on both ends of the support and the kernel, and uncertain values on other parts of the support. To have a comparison of the extended Kalman filter with other existing methods in the literature, particle swarm optimization and gradient descent-based methods are used. The proposed type-2 fuzzy neuro structure is tested on different noisy input–output data sets, and it is shown that extended Kalman filter has a better performance as compared to the gradient descent-based methods. Although the performance of the proposed method is comparable with the particle swarm optimization method, it is faster and more efficient than the particle swarm optimization method. Moreover, the simulation results show that the proposed novel type-2 fuzzy membership function with the extended Kalman filter has noise rejection property. Kalman filter is also used to train the parameters of type-2 fuzzy logic system in a feedback error learning scheme. Then, it is used to control a real-time laboratory setup ABS and satisfactory results are obtained. [ABSTRACT FROM PUBLISHER]

This paper presents a new fixed-carrier-frequency random pulsewidth modulation method, where a new type of carrier wave is proposed for modulation. Based on simulations and experimental measurements, it is shown that the spread effect of the discrete components from the motor current spectra and acoustic spectra is very effective and is independent from the modulation index. The flat motor current spectrum generates an acoustical noise close to the white noise, which improves the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits. The modulation method can be used in both open- and closed-loop motor control applications. [ABSTRACT FROM PUBLISHER]

In this paper, two methods for determining the fundamental frequency and harmonic positive- and negative-sequence components of three-phase signals are investigated. Many aspects of the space-vector discrete Fourier transform and generalized delayed signal cancellation (GDSC) such as response time for different possible implementations, frequency adaptation schemes, stability of recursive implementation, and rounding error effects are discussed. A new design procedure for GDSC transformations is presented. New indices for characterizing three-phase unbalanced and distorted signals are proposed. Simulations and experiments are included in order to verify the performances and illustrate the theoretical conclusions. [ABSTRACT FROM PUBLISHER]

This paper proposes an original association of a three-phase electrical machine, here a permanent-magnet synchronous motor (PMSM) fed by two inverters, which allows to combine two different functions: actuation and power transfers between two DC buses which supply the inverters. The considered AC machine is an open-end winding PMSM allowing the connection of two inverters supplied by two different DC buses inside a high-voltage DC network. The control part of this system uses the Park's theory not only to drive the actuator in motor as well as in generator operating modes but also to control the energy transfer from one DC bus to the other. The concept, mixing two main functions, is named MAPFC, for “mixed actuation and power flow control.” It has been particularly developed for aeronautic applications even if other application fields could be targeted. The complete modeling and operation of the system are described. Simulation studies and experimental results are presented, which are validating the proposed concepts. [ABSTRACT FROM AUTHOR]

In this paper, we consider the friction compensation problem for a class of mechanical systems. The friction behavior is described by a nonlinear dynamical model. Since it is difficult to know the nonlinear parts in the frictional model accurately, two neural networks (NNs) are employed in the proposed intelligent controller. Due to the learning capability of the NNs, the designed NN controller can compensate the effects of the nonlinear friction. Stability of the thus proposed learning control system is guaranteed by a rigid proof. Simulation and experimental results are provided to verify the effectiveness of the proposed intelligent scheme. [ABSTRACT FROM PUBLISHER]

This paper focuses on the problem of moving target tracking with a group of mobile robots. Each robot in the group has a pan/tilt camera to detect the target and has limited communication capability to communicate with neighbor robots. The problem is solved by separating it into two parts. One part is the estimation of target position and another is the flocking control of multiple robots moving toward the estimated position. In the target estimation part, we propose to use a novel distributed Kalman filter to estimate the target position. The distributed Kalman filter is deduced based on a standard Kalman filter by modeling the neighbor's information as one of measurements. In the motion control part, a distributed flocking algorithm is developed. It is used to track the estimated target and avoid collision. In both parts, only local communication between neighbor robots is required. Finally, the tracking algorithms are simulated with 2-D and 3-D robots to verify their performance. The simulation results provide a firm conclusion that the proposed algorithms are able to track a moving target. A group of real ground mobile robots is used to test the proposed algorithm. The experiment results show that multiple robots are able to cooperate to track the target under the proposed algorithms and the tracking result outperforms the result produced by individual robots without cooperation. [ABSTRACT FROM PUBLISHER]

In this paper, analytical techniques and fuzzy logic method are applied to the dynamic modeling and efficient swimming control of a robotic fish. The bioinspired robotic fish, which follows an exact replica of a live mackerel (Scomber scombrus), is modeled by treating the undulating body and flapping tail independently using analytical methods. Comparing the results of simulations and experiments shows the feasibility of the dynamic model. Using this model, we found that the harmonic control of the Strouhal number and caudal fin angle of attack is a principal mechanism through which the robotic fish can obtain high thrust efficiency while swimming. The fuzzy control method, which is based on the knowledge of the robotic fish's dynamic behavior, has successfully utilized this principal mechanism. By comparing the thrust performance of the robotic fish with different control methods via simulation, we established that the fuzzy controller was able to achieve faster acceleration and smaller steady-state error than what could be achieved from an open-loop and conventional proportional–integral-derivative controller. The thrust efficiency during steady state was superior to that with conventional control methods. We also found that, when using the fuzzy control method, robotic fish can always swim near a “universal” Strouhal number that approximates to the swimming of live fish. [ABSTRACT FROM PUBLISHER]

This paper proposes a three-phase current reconstruction technique with an online current offset compensation function for three-phase inverter applications utilizing only a single current sensor. In the proposed current sensing method, a phase current and a branch current are simultaneously measured twice in a switching period by using a single current sensor. After that, the current reconstruction algorithm is applied to obtain the three-phase current information. Compared to previous single current sensor strategies, in the proposed method, the sensor output is regularly sampled, and the dead zone is located near the boundary of the voltage vector space instead of near the origin and the borders of each sector. This boundary-neighbored dead zone makes the proposed method more attractive in extremely low modulation index cases because it avoids periodical dead zones which have been an issue in the existing methods. Moreover, the online compensation method for a current measurement offset makes it possible to achieve purely balanced three-phase current control without an offset component. The effectiveness of the proposed method has been verified through simulations and experiments by measuring and reconstructing three-phase currents under various conditions. [ABSTRACT FROM PUBLISHER]

In this paper, a current-source-converter (CSC)-based high-power high-speed (HPHS) permanent-magnet synchronous motor drive is proposed for high-speed compressor applications. The most important feature of the proposed CSC-fed HPHS drive is that the switching frequency is limited to 420 Hz at 200-Hz fundamental frequency. In the drive system, the whole operation range is divided into three regions, namely, the high-, medium-, and low-speed regions, where different modulation strategies and control schemes are used with the requirement of switching frequency and output filter. In particular, a two-pulse space vector modulation with dynamic capacitor voltage control is proposed for the high-speed region to achieve better dynamic and harmonic performance. Both simulation and experiments verify the proposed control strategy. [ABSTRACT FROM PUBLISHER]

This paper presents a retrofit system that exploits a fluorescent lamp's own stray electric fields for capacitive sensing. Occupancy detection for demand-side energy management is a key application. The experimental system demonstrates a detection range of 10 ft. between the lamp and the nearest edge of the occupant. A full system model is presented including the simulation of a lumped element capacitive model. The full system model is validated against experimental data. [ABSTRACT FROM AUTHOR]

In this paper, an input power factor compensation method is proposed for a high-power pulse-width-modulated current-source-converter (CSC)-fed permanent magnet synchronous motor (PMSM) drive system. The proposed method is based on controlling the d-axis stator current component in the field-oriented control (FOC) scheme of the drive system. The CSC-fed PMSM drive system and its FOC scheme are first introduced. Then, the relationships between the machine side, dc-link, and the line side are investigated. Based on the analysis, a new d-axis stator current control scheme that can ensure unity input power factor for the operating speed range is proposed. The main feature of the proposed scheme is to compensate the line-side power factor without the need for modulation index control in either the rectifier or the inverter. Therefore, offline Selective Harmonic Elimination (SHE) modulation schemes can be implemented on both line- and machine-side converters to minimize the total harmonic distortion. This results in reduced switching frequency and reduced switching losses. Simulation results for a 2.44 MW medium-voltage system and experimental results from a low-voltage 6.5 kW IPM motor drive are provided to verify the effectiveness of the proposed compensation method. [ABSTRACT FROM PUBLISHER]

In this paper, the single-input fuzzy logic controller (FLC) (SIFLC) for boost converter output-voltage regulation is proposed. The SIFLC utilizes the signed distance method that reduces the multidimensional rule table to 1-D with only one input variable, i.e., distance d. The simplification allows for the control surface to be approximated by a piecewise linear. It is shown that, despite the simplicity of SIFLC, its control performance is almost equivalent to that of the conventional FLC. As a proof of concept, the SIFLC is implemented using the Altera EP2C35F672C6N field-programmable gate array (FPGA) and applied on a 50-W boost converter. The SIFLC is compared to the proportional–integral controller; the simulation and practical results indicate that SIFLC exhibits excellent performance for step load and input reference changes. Another feature of this work is the absence of an external analog-to-digital converter (ADC). Instead, a simple analog-to-digital conversion scheme is implemented using the FPGA itself. Due to the simplicity of the SIFLC algorithm and the absence of an external ADC, the overall implementation requires only 408 logic elements and five input–output pins of the FPGA. [ABSTRACT FROM PUBLISHER]

This paper presents a novel approach to design RF tunable bandstop filters with constant absolute bandwidth. The filters are based on a doublet configuration which is attractive for high-order filter designs. In the doublet, two varactor-tuned resonators, arranged in a mirror-symmetrical manner, are coupled to a main transmission line. A novel coupling scheme is utilized between the resonators and the main line. Theoretical analysis indicates that, as the resonant frequency varies, the coupling coefficient within the fixed coupling region can be inherently changed to desirable values to meet the requirement of constant absolute bandwidth. Using the coupling scheme, constant absolute bandwidth can be obtained without extra circuits to control the coupling strengths. For demonstration, first-order and high-order filters are designed. Comparisons of experimental and simulated results are presented to verify the theoretical predications. [ABSTRACT FROM PUBLISHER]

Electronic load (E-load) is commonly used to test power supplies. In order to test computer power supplies, the E-load must possess an ideal controlled current source property which draws a desired load current even in the case of a very low terminal voltage of the source under test (SUT). It also needs to have superior dynamic performance to simulate high-slew-rate load transients. This paper proposes the design of a switching-converter-based E-load with very large operational bandwidth. The overall architecture of the E-load consists of a low-bandwidth converter, which functions under steady state, and a high-bandwidth auxiliary circuit that is only active during transient state. The converter circuit is realized using a novel switched-boost topology, and the auxiliary circuit is realized using a MOSFET operating at the edge of saturation and linear region. The proposed topology is capable of sinking a specific amount of load current even with a very low SUT terminal voltage. Simulation and experimental validations are provided to verify the proposed concepts. A prototype has been built to test the proposed architecture. The operational input voltage (SUT voltage) ranges of the prototype are between 0.5 and 6 V. The load current range is between 0.75 and 7 A. The results validate the excellent dynamic characteristics of the proposed architecture. [ABSTRACT FROM PUBLISHER]

Real-time electromagnetic transient simulation plays an important role in the planning, design, and operation of power systems. Inclusion of accurate and complicated models, such as the universal machine (UM) model and the universal line model (ULM), requires significant computational resources. This paper proposes a digital hardware emulation of the UM and the ULM for real-time electromagnetic transient simulation. It features accurate floating-point data representation, paralleled implementation, and fully pipelined arithmetic processing. The hardware is based on advanced field-programmable gate array (FPGA) using VHDL. A power system transient case study is simulated in real time to validate the design. On a 130-MHz input clock frequency to the FPGA, the achieved execution times for UM and ULM models are 2.5 \mu\s and 1.42 \mu\s, respectively. The captured real-time oscilloscope results demonstrate high accuracy of the emulator in comparison to the offline simulation of the original system in the EMTP-RV software. [ABSTRACT FROM PUBLISHER]

This paper continues the design considerations of a novel type of passive filter called hybrid LC filter (HLCF). The filter is aimed at significant reduction in high-frequency differential mode (DM) and common mode (CM) currents in speed-controlled ac drives. A model of the HLCF is presented. Based on the model, a transfer function of the HLCF is found. The HLCF behavior is analyzed in frequency domain. A method for HLCF frequency-domain behavior estimation with asymptotes is proposed. A comparison of the measured, simulated, and calculated results in frequency domain is presented. [ABSTRACT FROM PUBLISHER]

The matrix converter is a single-stage ac–ac power conversion device without dc-link energy storage elements. Any disturbance in the input voltages will be immediately reflected to the output voltages. In this paper, a modified space vector modulation strategy for matrix converter has been presented under the abnormal input-voltage conditions, in terms of unbalance, nonsinusoid, and surge (sudden rising or sudden dropping). By using the instantaneous magnitude and phase of input-voltage vector to calculate the voltage modulation index and input-current phase angle, this modified modulation strategy can eliminate the influence of the abnormal input voltages on output side without an additional control circuit, and three-phase sinusoidal symmetrical voltages or currents can be obtained under normal and abnormal input-voltage conditions. The performance of the input currents is analyzed when the matrix converter uses different modulation strategies. Some numerical simulations are presented to confirm the analytical results. Tests are carried out on a 5.5-kW matrix converter prototype. Experimental results verify the validity of the proposed strategy. [ABSTRACT FROM AUTHOR]

This paper proposes a new power-assist control in pushing task as an intelligent function of wheelchair by repulsive compliance control. In this strategy, the reaction force of human input into object is estimated without torque/force sensor and is utilized to generate the power-assist torque for wheel driving. The proposed approach brings a sophisticated function that makes it easy to carry out pushing task by wheelchair rider. First, human acceleration estimation observer (HAOB) and workspace disturbance observer (WDOB) are employed. HAOB can abstract human input as equivalent acceleration without torque/force sensor. WDOB guarantees robustness of the whole control system against disturbances. Second, HAOB-based compliance control is constructed to generate the motion command of pushing task for power-assist control. The generated motion command is determined so that the wheelchair accelerates according to human input. From this point of view, the proposed control is called repulsive compliance control. The compliance control itself is passive control, and stable and flexible responses are expected. Simulations and experiments are conducted to confirm the validity of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper presents a novel two-level scheme for adaptive active visual servoing of a mobile robot equipped with a pan camera. In the lower level, the pan platform carrying an onboard camera is controlled to keep the reference points lying around the center of the image plane. On the higher level, a switched controller is utilized to drive the mobile robot to reach the desired configuration through image feature feedback. The designed active visual servoing system presents such advantages as follows: 1) a satisfactory solution for the field-of-view problem; 2) global high servoing efficiency; and 3) free of any complex pose estimation algorithm usually required for visual servoing systems. The performance of the active visual servoing system is proven by rigorous mathematical analysis. Both simulation and experimental results are provided to validate the effectiveness of the proposed active visual servoing method. [ABSTRACT FROM AUTHOR]

Common-mode voltage (CMV) is responsible for overvoltage stress to the winding insulation and bearing damage of an ac motor. High dv/dt of CMV raises leakage currents, which can cause serious problems such as motor damage and electromagnetic noise to the equipment installed near the converter. This paper proposes two modulation strategies for indirect matrix converters that substantially eliminate CMV. The first method is developed by using the suitable couple of nonzero space vectors instead of zero space vectors in the inverter stage. The maximum voltage transfer ratio of this method is unaffected and remains 0.866. The second one, which is useful for low-voltage operation, is approached by choosing the medium and the lowest positive line-to-line input voltages in the rectifier stage to generate the dc-link voltage and by placing suitable zero space vectors in the inverter stage. In the second method, the maximum voltage transfer ratio is 0.5. Both methods can mitigate the peak value to 42%. In addition, while the first method provides the same performance to the conventional method, the second method can reduce significantly the harmonic components of line-to-line output voltage. Simulation and experimental results are shown to verify the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

This paper presents a baseband noise reduction method in the receiver for UHF RFID readers. The signal captured from the transmitter after passing through the main delay components is fed as an LO signal into the down-converter in the receiver. At the down-converter, the LO signal and the leakage signal from the transmitter to the receiver are mixed with each other. The matching of the delay between the two correlated signals virtually eleminates the additional baseband noise included in the phase noises after their mixing. Lowering the baseband noise improves the sensitivity of the receiver, thus allowing the RFID tags to be read further away from the reader. The proposed method was applied to a portable UHF RFID reader for its validation. Compared to the conventional configuration, the simulated baseband noise level of more than 26 dB was reduced by the proposed method. The measured sensitivity of about 19 dB was also improved. As a result, the reading distance was extended by 1.9 m from 2.02 to 3.92 m. [ABSTRACT FROM AUTHOR]

Multilevel voltage-source converter topologies are widely used today in high-power applications such as medium-voltage drives. On the other hand, studies on matrix converters (MCs) have been mainly limited to the low power range. With the intention to combine benefits from both multilevel structure and direct power conversion, this paper investigates the topologies and operating principles of multimodular MCs (MMMCs). Composed of three-phase-to-single-phase MC (3 \times 2 MC) modules, two versions of MMMCs are presented and studied. Modulation schemes to synthesize sinusoidal waveforms on both input and output sides of the converters are elaborated. Having features such as modular design, relatively low switching frequency, and capability of using low-voltage power semiconductor devices, the presented MMMCs are intended for possible use in higher power applications where four-quadrant operation and fast dynamic response are expected. Simulation and experimental results are provided to verify the validity of the study. [ABSTRACT FROM AUTHOR]

The matrix converter (MC) is arousing considerable attention as an alternative for conventional ac/ac converters due to the advantages it offers. However, the control and modulation of this converter is complex. This, together with the fact that the MC usually operates at high modulation frequencies, makes the computational load of the platform to be simulated excessively high. All this makes the simulation time of models including the MC excessively long, even more so when both the transient and steady state of the system must be analyzed. This paper presents a new MC simulation technique called Switching State Matrix Averaging (SSMA). Although this is a fixed-step technique, a long simulation step can be used without forfeiting the accuracy of an ideal variable-step simulation. Likewise, the SSMA drastically speeds up the simulation, reducing the amount of required resources and the tuning time of the complex platforms in which the MC is used. A series of simulations has been performed in order to verify the proposed method. Moreover, a comparison between experimental and simulation results has been made, demonstrating the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, the effect of equivalent series resistance (ESR) of an output capacitor on the performance of a constant-on-time (COT)-controlled buck converter is studied, and a pulse bursting phenomenon is revealed. It indicates that the ESR of the output capacitor is one of the key factors causing pulse bursting phenomenon in COT-controlled buck converters, and the critical ESR is derived via time-domain analysis and stability analysis in the s-domain. It is pointed out that, when the ESR of the output capacitor is smaller than the critical ESR, pulse bursting phenomenon occurs; otherwise, it disappears. Simulation and experimental results are provided to verify the theoretical analysis results. [ABSTRACT FROM AUTHOR]

In this paper, a modified Z-source inverter (ZSI) with specific modulation techniques is proposed to reduce leakage currents in three-phase transformerless photovoltaic (PV) systems. The new topology only requires an additional fast-recovery diode when compared with the original structure. On the other hand, the pulsewidth modulation technique is entirely modified in order to reduce the leakage currents through the conduction path. Simulation results for the three-phase transformerless PV system operating in two cases, i.e., connected to a grid and connected to a grounded RL load, are presented. Experimental results of leakage currents in three-phase ZSIs connected to a RL load are obtained to validate the theoretical and simulation models. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the problem of robust static output feedback (SOF) control for networked control systems (NCSs) subject to network-induced delays and missing data. The uncertain system matrices are assumed to lie in a convex polytope. The network-induced delays are time varying but within a given interval. The random data missing is characterized by the Bernoulli random binary distribution. Delay-dependent conditions for the exponential mean-square stability are first established in terms of matrix inequalities. Then, for the robust stabilization problem, the design of an SOF controller is presented by solving bilinear matrix inequalities (BMIs). In order to efficiently solve a nonconvex BMI, we propose an approach based on the linear matrix inequality technique. Furthermore, the developed approach is employed to design the remote proportional–integral–derivative (PID) controller for NCSs. The design of a digital PID controller is formulated as a synthesis problem of the SOF control via an augmentation method. Simulation examples illustrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

This paper presents an electromagnetic interference (EMI) model to evaluate the conducted common mode (CM) disturbances produced by matrix converters (MCs). The model is based on obtaining a high frequency (HF) equivalent circuit with HF sources representing the switching devices. The circuit resolution in the frequency domain allows the calculation of any EMI parameter with very low computational burden and avoids convergence problems, which are common in time domain methods. The original contribution lies in the source model implementation and placement. The simulation and experimental results for CM leakage currents validate the EMI model. [ABSTRACT FROM PUBLISHER]

Operation under light-load conditions is a general issue when developing power converters as it can lead to system instability and/or decreased performance. This topic is particularly important for resonant converters as their efficiency significantly reduces when their operation point is set outside their resonant conditions. Considering the importance of efficiency for power converter reliability, environmental impacts, and regulation concerns, a major effort to improve the operation under light-load conditions is justified. Domestic induction heating is an application where variable loads and output power requirements imply operation under a wide range of conditions, including long-term light-load operation. The aim of this paper is to propose an improved control scheme for series resonant multiinverters, which are a cost-effective topology for supplying multiple inductive loads, based on discontinuous-mode operation. Two different control strategies are proposed: regenerative control and direct conduction control. An analytical study is performed, and the main simulation results are presented. An experimental series resonant multiinverter prototype is used to validate the simulation results. [ABSTRACT FROM PUBLISHER]

A sensorless method for the direct estimation of the slip position of the wound-rotor induction machine is introduced, discussed, and experimentally validated in this paper. The slip position is necessary for the implementation of control by flux orientation. The method proposed is based on the phase comparison of an estimated air-gap power vector and the measured rotor currents in a common reference frame. The proposed method can be implemented in the rotor or in the field reference frames with a hysteresis or proportional–integral controller. The method is sensitive to the stator no-load active and reactive powers, but this dependence is not very important. Simulation and experimental results show that the method is appropriate for the vector control of the doubly fed induction machine. Unlike other methods, this method gives acceptable results when the load is small. In addition, it does not need a flux estimator for the implementation of flux orientation. [ABSTRACT FROM AUTHOR]

The problem of attitude stabilization for a spacecraft system which is nonlinear in dynamics with inertia uncertainty and external disturbance is investigated in this paper. An adaptive law is applied to estimate the disturbances, where a sliding mode controller is designed to force the state variables of the closed-loop system to converge to the origin. Then, the spacecraft system subjected to control constraints is further considered, and another adaptive sliding mode control law is designed to achieve the attitude stabilization. No prior knowledge of inertia moment is required for both of the proposed adaptive control laws, which implies that the designed control schemes can be applied in spacecraft systems with a large parametric uncertainty existing in inertial matrix or even in unknown inertial matrix. Also, simulation results are presented to illustrate the effectiveness of the control strategies. [ABSTRACT FROM AUTHOR]

This paper presents a controller-design methodology for a class of underactuated mechanical systems that are affected by parametric uncertainties and external disturbances. The perturbations due to parametric uncertainties are mismatched, whereas those caused by external disturbances are of the matched type. Their effects are canceled by employing a novel strategy that combines time scaling and Lyapunov redesign. The control methodology is applied to a two-wheeled mobile inverted pendulum and a ball–beam system. Along the way, the nonexistence of a smooth control law for point-to-point stabilization of the mobile inverted pendulum is established. Simulation and experimental studies are used to verify the efficacy of the proposed controller-design method. [ABSTRACT FROM AUTHOR]