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In this paper, the design of dynamic output feedback control law for polynomial fuzzy systems is studied. The main purpose is to design a tracker control law for fuzzy polynomial systems that are subject to external bounded disturbances. The structure of the control law is considered as fuzzy proportional–integral control. The conditions for deriving the control law are formulated in the form of a sum of square (SOS) feasibility problem. The designed control law will be able to force the system state vector to follow the state vector of a stable reference model in addition to guaranteeing the H∞ performance measure. The simulation results show the efficiency of the proposed method exposed to external disturbance. [ABSTRACT FROM AUTHOR]

This study elaborates upon a new modular split‐tooth permanent magnet‐assisted switched reluctance motor (MSTPM‐SRM). In the proposed topology, the stator comprises six modular E‐cores in which the middle poles are split into two teeth. Two permanent magnets (PMs) are placed between each module's middle and side poles. Primarily, the proposed topology is introduced. Next, the principle of operation of the proposed topology are elucidated, and the magnetic equivalent circuit analysis is adopted in order to validate the operational basics. It is proved that the embedded PMs significantly increase the air‐gap's flux density and adjusts the poles' flux density. The flux density distributions, static, and steady‐state characteristics of the proposed MSTPM‐SRM motor and its PMless counterpart are extracted by utilising 2‐D finite element analysis. It is illustrated that the average torque of the proposed MSTPM‐SRM is dramatically increased compared to its PMless counterpart, especially at high excitation currents. Furthermore, the cogging torque analysis is done and it is shown that the proposed structure has approximately zero cogging torque. Finally, a prototyping version of the proposed motor is fabricated, and the experimental results are elicited. It is shown that the experimental results endorse the simulation results. [ABSTRACT FROM AUTHOR]

This paper introduces a new high step‐up multi‐input multi‐output (MIMO) DC–DC converter control‐based pole placement suitable for photovoltaic system applications. The suggested topology has a high stability current control. Low element number, high voltage conversion ratio, and low ripple input current are the main advantages of the proposed converter. The capability to use several energy resources with different voltage/current characteristics, increase the number of inputs and outputs arbitrary without duty‐cycle limitation, and control each input unit power switch independently are other advantages. The operation principle of the suggested topology, steady‐state analysis in continuous condition mode (CCM), and parameter design are analyzed. A comparison between the suggested topology and other converters is applied. Two‐input two‐output version of the suggested topology in 200 W at an operating 50 kHz switching frequency is analyzed. Finally, the Typhoon HiL‐404 emulating setup is applied to verify the performance and efficiency of the suggested high‐step‐up MIMO DC–DC power converter. [ABSTRACT FROM AUTHOR]

This work proposes a novel topology of two‐output high voltage rate DC‐DC converter based on coupled inductor and voltage multiplier cells (VMCs) techniques for renewable energy usages like photovoltaic (PV) systems. The proposed structure has two independent output ports with two voltage gains (M1 and M2). Low voltage stress across the power switch and diodes, common ground between input and output ports, high efficiency, and reduced number of elements are the advantages of the suggested converter. The used diodes are switched at zero current switching (ZCS) and zero voltage switching (ZVS) conditions, which reduce the losses of diodes and subsequently increase the power efficiency. Due to the usage of the coupled inductor, there is no need to a high value of the power switch's duty cycle. Therefore, a low conduction loss and higher efficiency can be obtained. On the other hand, because of the reduced voltage stresses, low rated semiconductors can be used for operation of the presented converter, which decrease the cost and the volume. To demonstrate the performance and effectiveness of the proposed topology, operation principles, steady‐state and efficiency analysis, and also the comparison assessment are provided. Finally, a 200 W experimental development with 50 kHz operation frequency, 20 V input voltage, and 200 and 100 V loads voltages has been implemented in the lab to prove the mathematical surveys. [ABSTRACT FROM AUTHOR]

Summary: In this study, a novel method is proposed for current control (CC) of an active power filter (APF) of the aircraft power system, which is based on a fuzzy inference system (FIS). The control system is designed according to the instantaneous power theory. Two other conventional CC methods consisting of the hysteresis current control method (HCCM) and adaptive hysteresis current control method (AHCCM) are utilized in the study and their results are compared with the proposed fuzzy current control method (PFCCM). It is shown that the proposed method is more successful in eliminating harmonics without drawbacks of conventional methods such as high and variable switching frequency which hardens system design and utilization. The study is carried out in MATLAB\Simulink environment to prove the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

Summary: A single‐switch ultra‐high voltage DC‐DC converter is proposed in this paper. In the introduced structure, a voltage multiplier cell (VMC) and three‐winding coupled inductor (CL) are integrated to obtain an ultra‐large voltage gain. The input current ripple of the presented configuration is very low due to utilizing an inductor in the input part of the converter which is a very important factor in clean energy applications. The CL leakage inductance energy is successfully recovered, and the main power switch voltage stress is clamped because of using a passive clamp circuit. Therefore, a switch with low os‐state resistance can be applied, which declines the conduction losses as well as the cost of the suggested topology. Moreover, the common ground between the input and output of the proposed configuration makes it suitable for many applications such as photovoltaic systems. Some important merits include ultra‐high voltage gain, operating in low duty cycles, reduced voltage stress of semiconductors, continuous input current, and high efficiency, which make the introduced converter very suitable for clean energy applications. The operation principle, steady‐state analysis, design considerations, and theoretical efficiency analysis of the suggested converter are discussed completely in the paper. Also, the superiority of the proposed converter over recently suggested similar most important DC‐DC converters is demonstrated in the comparison study. Finally, the performance and theoretical analysis of the converter are validated with the experimental results at an output voltage of 450 V and an output power of 250 W. [ABSTRACT FROM AUTHOR]

This article presents a novel high-temperature superconductive (HTS) power flow controller and current limiter (PFCCL), which limits fault currents and manages power flow in the intended transmission line. The proposed device includes series HTS reactors, HTS controlling dc coil, recovery resistive coil, and power electronic switches, which protects the microgrid from the upstream ac grid, short-circuit faults, and it controls the power flow between a microgrid and the upstream grid. Performance of the proposed PFCCL is mathematically analyzed, utilizing MATLAB and Maxwell software, and then validated by laboratory scaled-down experimental setup. It is shown that the simulation results are in fair agreement with the developed experimental laboratory setup results. [ABSTRACT FROM AUTHOR]

Featured Application: Investigation of electric load demand management upon the hydrogen consumption and the optimum power size of fuel cell for the aircraft industry is the specific application of this research work. The proton exchange membrane fuel cell as a green power source is a suitable replacement of the engine mounted generators in the emergency power unit of a more-electric aircraft. Most existing energy management methods for operation of fuel cells in the more-electric aircraft refer to the hydrogen consumption minimization. But due to the increasing number of electrical components and hence electrical demand in the aircraft, demand-side management should be considered in these methods. In order to determine the effect of demand-side management on the fuel cell operation and size, an efficient load priority model is presented and integrated into an optimization framework. The proposed optimization framework is formulated as mixed-integer quadratic programming using Karush–Kuhn–Tucker optimality condition and is solved by CPLEX optimization tool. The Boeing 787 electrical distribution system is considered as a single-bus case study to evaluate the performance of the proposed optimization framework. Numerical results show that the size of fuel cell as an emergency power unit resource depends on the type and importance of the system's loads in different emergency conditions. Also, with an efficient priority model, both hydrogen consumption and load shedding can be decreased. [ABSTRACT FROM AUTHOR]

Expansion of high-voltage dc (HVdc) systems to multi-terminal HVdc (MT-HVdc) systems/grids considerably increases the short-circuit levels. In order to protect the emerging MT-HVdc systems/grids against fault currents, proper dc fault current limiters (FCLs) must be developed. This paper proposes an innovative high inductance solid-state dc-reactor-based FCL (HISS-DCRFCL) to be used in HVdc applications. In fact, during the HISS-DCRFCL normal operation, its inductance value is extremely low, and its value becomes considerably high during the fault period, which decreases the fault current amplitude. The proposed HISS-DCRFCL performance is analyzed by MATLAB/Simulink and the simulation results are verified and confirmed by laboratory experimental results using a scaled-down laboratory prototype setup. [ABSTRACT FROM AUTHOR]

Ferroresonance occurrence is a source of damage, causing overvoltage on voltage transformer (VT) and isolators of the grid equipment. Some solutions are available to protect VTs from the ferroresonance overvoltage. However, they just act after the ferroresonance occurrence. In this letter, to prevent the occurrence of ferroresonance, a dc reactor-based protection device is introduced. Analytical studies and simulations by MATLAB/Simulink and Maxwell ANSYS demonstrate the capability of the proposed protection device as a VT ferroresonance inhibitor. Experimental results from a scaled-down laboratory prototype are also provided to verify the proposed solution. [ABSTRACT FROM AUTHOR]

In this brief, a robust correntropy-based adaptive learning algorithm, called the adaptive kernel recursive maximum correntropy criterion, is proposed by considering an adaptive kernel size based on the Kullback–Leibler divergence minimization. Simulation results confirm that the proposed algorithm can perform better than other adaptive algorithms especially when the environment is disturbed by non-Gaussian noises. The proposed algorithm is beneficial for using in helicopters, since the pilot speech signal is contaminated by the acoustic impulsive noises that are originated from rotor blades. [ABSTRACT FROM AUTHOR]

This paper proposes a smart dual function series resonance ferroresonance overvoltage and fault current limiter (SRFFCL) for distribution networks. The studied network has potential transformers (PTs) with a typically low thermal capacity and high accuracy. The PT core losses are assumed to be constant during ferroresonance oscillation. The MATLAB software is used for simulation of the novel SRFFCL in distribution network, to study the PT ferroresonance overvoltage and fault current. Also, experimental results are obtained using a laboratory prototype. Both the simulation and experimental results, which are in good agreement with each other, show that the suggested SRFFCL can not only control the fault current but also adequately decrease the ferroresonance oscillation of the PT. [ABSTRACT FROM AUTHOR]

In some aircraft with traditional distribution electrical systems, the sources, distribution, and electrical loads are fully coupled. The control surfaces in traditional aircraft are based on cables and hydraulic actuators. Furthermore, the system stability mainly related to the hydraulic system and a small portion of it is related to the electrical system reliability. However, for aircraft like A380 and B787, the flight system is based on fly by wire (FBW) technology and more electric aircraft (MEA) have drawn the attention of aircraft designers. In addition, more hydraulic actuators change to the electrical actuator, which leads to more electrical generation usage. The availability of electrical energy to the loads is only ensured through overdesign, system reconfiguration, and protection. Power electronic converters are starting to be used to fully decouple the dynamics between sources, distribution systems, and loads. [ABSTRACT FROM PUBLISHER]

This study presents a novel DC reactor‐based ferroresonance and fault current limiter (DRFFCL) for stabilising ferroresonance oscillations of potential transformer (PT) in 33 kV distribution network and decreasing the amplitude of the fault current to an acceptable level. At first, the ferroresonance overvoltage is introduced and various types of overvoltage in the PT are studied. Then, the effects of the suggested DRFFCL on these oscillations are investigated. It is shown that the proposed DRFFCL not only can control the ferroresonance oscillations, but also can decrease the fault current amplitude in the case of short‐circuit faults occurrence. The DRFFCL performance is simulated using MATLAB software and a scaled‐down laboratory prototype is implemented and tested for the simulation results validation. The measured results are in agreement with the simulation results and clearly show the ability of the DRFFCL for controlling both the ferroresonance overvoltage and fault current. [ABSTRACT FROM AUTHOR]

In this paper, a novel solid-state fault current-limiting circuit breaker (SSFCLCB) based on a series resonance LC tank is proposed. Since the series configuration of the resonance structure (a capacitor and a reactor) of the SSFCLCB is invisible during normal operation mode, it shows negligible impedance in the line. In fault conditions, the SSFCLCB topology changes to a rectifier bridge and feeds the resonance structure with rectified ac voltage. With the rectified voltage, the series capacitor is charged and, as a result, the faulty line is opened and the fault current is seized. Hence, the suggested SSFCLCB cannot only limit the fault current but can also open the faulty line and acts as a circuit breaker. For confirmation of these aspects, simulations are performed using MATLAB software. Also, a prototype structure is designed and built for results confirmation. This experimental setup is established to prove that SSFCLCB has excellent performance in its startup, normal operation, and current-limiting/breaking conditions. The results show that the SSFCLCB has the ability to improve distribution network reliability and it can decrease the network fault current level successfully. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel bridge-type solid-state fault current limiter (BSSFCL) based on one series reactor which operates in ac and dc modes. The proposed BSSFCL includes a rectifier bridge with a reactor. This reactor is used as a dc reactor in normal operation mode and as an ac reactor in fault conditions. The advantages of the proposed BSSFCL over the existing dc reactor-type FCLs are its negligible impedance in normal operation mode and its high impedance during a fault interval using simple and novel switching. In other words, during the normal operation mode, the proposed BSSFCL operates in dc mode and in the fault interval, its topology is changed to the ac mode. This switching decreases the switching transient recovery voltage and introduces considerable impedance during the fault period. MATLAB/Simulink software is used for simulations and a prototype is designed and tested for results verification, and to show the performance of the proposed BSSFCL. [ABSTRACT FROM PUBLISHER]

This paper studies a novel transformer-based solid state fault current limiter (TBSSFCL) for radial distribution network applications. The proposed TBSSFCL is capable of controlling the magnitude of fault current. In order to control the fault current, primary winding of an isolating transformer is connected in series with the line and the secondary side is connected to a reactor, paralleled with a bypass switch which is made of anti-parallel insulated gate bipolar transistors. By controlling the magnitude of ac reactor current, the fault current is reduced and voltage of the point of common coupling is kept at an acceptable level. Also, by this TBSSFCL, switching overvoltage is reduced significantly. The proposed TBSSFCL can improve the power quality factors and also, due to its simple structure, the cost is relatively low. Laboratory results are also presented to verify the simulation and theoretical studies. It is shown that this TBSSFCL can limit the fault current with negligible delay, smooth the fault current waveform, and improve the power quality. [ABSTRACT FROM PUBLISHER]

In this article, a simple case of ferroresonance in a three-phase transformer is used to study the effect of a metal oxide surge arrester on the control of chaotic ferroresonance and duration of chaotic transient in a power transformer including non-linear core losses. The time-domain simulations are derived using MATLAB (The MathWorks, Natick, Massachusetts, USA) for a three-phase 50-MVA, 635.1-kV power transformers while one of its phases is opened. The magnetization characteristic of the power transformer is modeled by a single-value two-term polynomial. The non-linear core losses are modeled by a third-order power series in terms of voltage, and the core losses non-linearities are considered as well. The simulation results show that connecting the metal oxide surge arrester to the transformer exhibits a great suppressing effect on occurred ferroresonance over-voltage. [ABSTRACT FROM PUBLISHER]

This paper studies the effect of zinc oxide arrester (ZnO) and neutral earth resistance on controlling nonconventional oscillations of the unloaded power transformer. At first, ferroresonance overvoltage in the power system including ZnO is investigated. It is shown this nonlinear resistance can limit the ferroresonance oscillations but it cannot successfully control these phenomena. Because of the temperature dissipation of ZnO, it can withstand against overvoltage in a short period and after that ferroresonance causes ZnO failure. By applying neutral earth resistance to the system configuration, mitigating ferroresonance has been increased and chaotic overvoltage has been changed to the smoother behavior such as fundamental resonance and periodic oscillation. The simulation results show that connecting the neutral resistance exhibits a great mitigating effect on nonlinear overvoltage. [ABSTRACT FROM AUTHOR]

Ferroresonance is a non-conventional electrical phenomenon which may cause overvoltages in the electrical power system endangers the system reliability. This paper studies the effect of circuit breaker shunt resistance, Metal Oxide Surge Arrester (MOSA) and neutral earth resistance on controlling chaotic ferroresonance in a potential transformer while transformer core losses is modeled as a nonlinear resistance which hysteresis and eddy current losses are included. It is expected that neutral earth resistance can control ferroresonance better than MOSA and circuit breaker air gap resistance. For confirmation this aspect, simulation has been done on a one phase potential transformer rated 100VA, 275kV. Simulation results show that considering shunt resistance on the circuit breaker and MOSA in parallel to the transformer, exhibits a great mitigating effect on ferroresonance oscillations, but these resistances cannot control these phenomena for wide variation of the power system parameters. By applying neutral earth resistance to the system grounding, ferroresonance is controlled and its amplitude has been damped for all parameters values. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of linear and nonlinear core losses on the onset of chaotic ferroresonance and duration of transient chaos in an autotransformer and control of these phenomena by applying neutral earth resistance to the system grounding. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial. The nonlinear core loss is modeled by a third order power series in voltage with nonlinearities in core loss included, four effects are clear: (i) onset of chaos at larger values of open phase voltage, (ii) shorter duration of transient chaos,(iii) less susceptibility to 'jump' phenomena and (iv) effect of neutral resistance on controlling of ferroresonance phenomena. It is also shown that nonlinear core losses also can cause ferroresonance drop out. [ABSTRACT FROM AUTHOR]

This paper studies the effect of MOV surge arrester on chaotic ferroresonance over voltages in potential transformer (PT) including nonlinear core losses effect. It is expected that MOV generally can cause ferroresonance 'dropout'. Time-domain study has been carried out to study this effect. Simulation has been done on a potential transformer rated 100VA, 275 kV. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial with order seven. The core loss is modeled by nonlinear resistance. Simulation results reveal that connecting the MOV in parallel with the potential transformer, exhibits a great controlling effect on ferroresonance over voltages. Phase plane, voltage waveforms, along with bifurcation diagrams are also derived. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos along with ferroresonance over voltages has been obtained and presented. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of linear and nonlinear core losses on the onset of chaotic ferroresonance and duration of transient chaos in an autotransformer and control of these phenomena by considering nonlinear core losses effect. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial. The nonlinear core losses are modeled by a third order power series in voltage with nonlinearities in core losses included, four effects are clear: (i) onset of chaos at larger values of open phase voltage, (ii) shorter duration of transient chaos, and (iii) less susceptibility to 'jump' phenomena and finally, (iv) great controlling effect of nonlinear core losses on the chaotic ferroresonance oscillation in autotransformer. It is shown that nonlinear core losses can cause ferroresonance drop out. For confirmation these aspects, nonlinear study is done by using MATLAB/Simulink and nonlinear dynamical tools such as bifurcation and phase plan diagram are used to shown the simulation results. [ABSTRACT FROM AUTHOR]

Ferroresonance or nonlinear resonance is a complex electrical phenomenon, which may cause over voltages and over currents in the electrical power system which endangers the system reliability and continuous safe operating. The ability to predict or confirm ferroresonance depends primarily on the accuracy of the transformer model used by the computer simulation. An overview of available literature and contributors to this area is provided. This paper studies the effect of circuit breaker shunt resistance on the controlling chaotic ferroresonance in a voltage transformer while the core losses of the voltage transformer core are highly nonlinear. It is expected that this resistance generally can cause ferroresonance 'dropout'. For confirmation this aspect Simulation has been done on a one phase voltage transformer rated 100VA, 275kV. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial with q=7. The simulation results reveal that considering the shunt resistance on the circuit breaker in the case of nonlinear core losses, exhibits a great mitigating effect on ferroresonance over voltages. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos along with ferroresonance over voltages has been obtained and presented. [ABSTRACT FROM AUTHOR]

Current power systems will suffer from increasing pressure as a result of an upsurge in demand and will experience an ever-growing penetration of distributed power generation, which are factors that will contribute to a higher of incidence fault current levels. Fault current limiters (FCLs) are key power electronic devices. They are able to limit the prospective fault current without completely disconnecting in cases in which a fault occurs, for instance, in a power transmission grid. This paper proposes a new type of FCL capable of fault current limiting in two steps. In this way, the FCLs' power electronic switches experience significantly less stress and their overall performance will significantly increase. The proposed device is essentially a controllable H bridge type fault current limiter (HBFCL) that is comprised of two variable inductances, which operate to reduce current of main switch in the first stage of current limiting. In the next step, the main switch can limit the fault current while it becomes open. Simulation studies are carried out using MATLAB and its prototype setup is built and tested. The comparison of experimental and simulation results indicates that the proposed HBFCL is a promising solution to address protection issues. [ABSTRACT FROM AUTHOR]

The protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter and circuit breaker (CLCB) which can limit fault current and fast break to adjust voltage sags at the protected buses. In addition, it can act as a circuit breaker to open the faulty line. The proposed CLCB is based on a series L-C resonance, which contains a resonant transformer and a series capacitor bank. Moreover, the CLCB includes two anti-parallel power electronic switches (a diode and an IGBT) connected in series with bus couplers. In order to perform an analysis of CLCB performance, the proposed structure was simulated using MATLAB. In addition, an experimental prototype was built, tested, and the experimental results were reported. Comparisons show that experimental results were in fair agreement with the simulation results and confirm CLCB's ability to act as a fault current limiter and a circuit breaker. [ABSTRACT FROM AUTHOR]