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Современное инженерное образование – сплав содержания и технологий обучения. Среди новых эффективных технологических средств обучения и автоматического контроля учебных достижений студентов, формирующих у них профессиональные умения и владения, нашли себе место учебно-программные тренажеры.В статье рассматриваются вопросы разработки и использования учебно-программных тренажеров при изучении курса «Электротехника» в вузе, благодаря которым появилась возможность с уменьшением времени приобрести владение построением топографических и временных диаграмм напряжений и токов в цепях однофазного переменного тока., Modern engineering education is a fusion of content and learning technologies. The new effective technological means of training and automatic control of students' learning achievements, which form their professional skills and competences, include training and program simulators.The article considers the development and use of educational program simulators for the university course of "Electrical Engineering" due to which it became possible to acquire mastery of the construction of topographic and vector diagrams of voltages and currents in circuits of single-phase alternating current with a reduction in time., Международный научно-исследовательский журнал, Выпуск 9 (123) 2022

In this research paper, analytical equations of the transient characteristics of a new remote transformer current converter without a compensating capacitor have been obtained when a stepwise, linearly increasing, sinusoidal and sinusoidal with a damped amplitude of effects was applied to their input. It has been shown that the developed current converter can be represented in the structural schemes of monitoring and control systems in the form of a series-connected real ifferentiating link without statism and inertial (aperiodic) link of the first order, and in the case of neglecting active losses in the magnetic circuit and when the converter is operating in idle mode, i.e in the form of ideal differentiating link.It has been established that the transient response of the developed current transducer has an aperiodic character when a surge primary current is fed to its input, and with a relatively very large value of the time constant of the secondary circuit compared to the time constant of the magnetic circuit, transient response approaches transient response of a real differentiating link.

This article deals with a complete evaluating and comparative analysis involving static and dynamic performances of a three-phase unified power quality conditioner (UPQC) controlled to operate using conventional and dual/inverted compensation strategies for performing active power-line conditioning. In the conventional strategy, the series converter of the UPQC operates as a nonsinusoidal voltage source, while the parallel converter operates as a nonsinusoidal current source. Differently, when the UPQC operates with a dual/inverted strategy, the series converter operates as a sinusoidal current source, while the parallel converter is controlled to act as a sinusoidal voltage source. Although, in theory, the results achieved using the mentioned strategies looks similar, in practical applications there are considerable differences in both static and dynamic performances that must be considered for choosing the best compensation strategy to be adopted. Thus, this article addresses aspects related to the mathematical modeling, control and generation of the control references applied to the UPQC, which are implemented using two three-level neutral-point clamped inverters. Furthermore, the performance of the UPQC operating under static disturbances (grid voltage harmonics/unbalances and load current harmonics), as well as dynamic disturbances (voltage sags/swells and load changes) are extensively tested by means of an experimental setup.

Two new power factor correction (PFC) rectifiers with the voltage buck-boost capability are proposed in this article, called as Ferdowsi rectifiers (FRs). The proposed rectifiers employ a reduced number of semiconductors compared to the competitors. Also, since the reverse recovery problem of antiparallel diodes of transistor switches is avoided, then MOSFETs can be readily utilized, which lets much higher switching frequencies and lower size of passive components. In addition, two parallel capacitors provide a path for the input current during the discharge mode of the buck-boost inductors to improve the current quality. The discontinuous conduction mode operation of the proposed rectifiers guarantees a high quality input current with a low total harmonic distortion. All aforementioned features offer a highly efficient operation and at the same time a purely sinusoidal current drawn from the ac source compared to the previous well-developed competitors. The validation of the theoretical achievements is performed by extensive tests on a laboratory test rig.

The magnetic system of the installation to control the transverse dimensions of an electron beam formed by a magnetron gun with a secondary emission cathode was updated. An additional solenoid with pulsed power supply located in a vacuum chamber at a distance of 0.05...0.1 m from the gun’s edge will be used in experiments. The solenoid design was selected and calculated. Possibility of a magnetic field generation of amplitude of up to 0.5 T at amplitude of the pulse current of ~ 1.5 kA, was demonstrated. The field has a uniform area at the level of ± 5% over the length of ~ 0.2 m.

Open-phase fault is a common failure in permanent magnet synchronous motor (PMSM), which would degrade motor performance and increase its loss due to the unbalanced phase currents. However, conventional fault-tolerant strategies suffer from the tracking problem of sinusoidal current references. In this paper, different from previous fault-tolerant strategies, a new fault-tolerant method for open-phase PMSM is proposed by designing a novel transformation matrix for current/voltage references. With the new transformation matrix, the voltage/current references in the d–q frame can be transformed to the phase voltage/current references of the two remaining phases. With the proposed method, open-phase fault-tolerant implementation can be much easier (proportional-integral controller is enough) and its performance can be much higher. Besides, as the tolerant method is designed based on the four-leg inverter, stronger fault-tolerance capability can be obtained compared with the three-phase inverter-based method. Finally, the experimental results confirm the validity of the proposed fault-tolerant method.

This paper presents the current control design procedure of a single-phase grid-tied five-level packed U-cell inverter (PUC5) with an LCL output filter. The PUC5 inverter is used as an interface of renewable energy sources, such as solar applications. The LCL filter is calculated according to the grid-tied operation and converter ratings. An optimal controller, based on a linear quadratic regulator with integral action, is designed to inject a sinusoidal current with low harmonic distortion at unity power factor. For that design, the PUC5 inverter is modelled in the D – Q frame. The sensorless voltage control is incorporated into the switching technique to balance the PUC5 capacitor voltage and generate a five-level waveform at the output. Experimental tests are performed on a laboratory benchmark to confirm the theoretical design. The results prove the efficiency and accuracy of the adopted control strategy in a steady state and under transients of grid current, grid inductance, ac and dc voltage amplitudes.

Open-phase fault may lead to motor efficiency and performance degradation. Various fault-tolerant methods have been proposed to reconfigure the controller and to track the sinusoidal current references. Unfortunately, the time-varying sinusoidal current commands are difficult to be tracked. In order to improve open-phase permanent magnet synchronous motor (PMSM) performance, a new open-phase PMSM fault-tolerant method is proposed in this paper, which is realized based on a novel reference frame transformation. With the new frame transformation, the position-dependent sinusoidal current commands are transformed to dc variables. Thus, the current controller design becomes very easy (PI controller is enough). The experimental results confirm that with the proposed method the PMSM fault-tolerant performance is enhanced distinctly compared with the conventional fault-tolerant methods.

The article presents various concepts of three-phase power rectifiers with improved quality of converted electric power. This effect is obtained by modulating the currents in the DC output circuits of the rectifiers by means of power electronics controlled voltage or current sources, working as a so-called voltage or current modulators. For further quality improvement of the grid currents of the analyzed systems, it was proposed to use an additional controlled current source connected in parallel to the DC load, hereinafter referred to as a supporting system. The original elaborated method of controlling this source (supporting system) was presented. The main goal of the work was to propose a solution for an effective method of improving the quality of energy conversion in rectifier systems, especially high power ones, by using controlled current sources in DC circuits, operating as the power electronics current modulator and the supporting system.

State-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and high power density, leading to a challenging power converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) harmonic content, can be a major contributor to the overall converter size and losses. Therefore, this paper proposes a complete analysis, design and optimization procedure of a three-phase LCL filter for a modular DC fast charger. First, an overview of the basic LCL filter modeling is provided and the most significant system transfer functions are identified. Then, the optimal ratio between grid-side and converter-side inductance is discussed, aiming for the maximum filtering performance. A novel design methodology, based on a graphical representation of the filter design space, is thus proposed. Specifically, several constraints on the LCL filtering elements are enforced, such that all feasible design parameter combinations are identified. Therefore, since in low-voltage high-power applications the inductive components typically dominate the overall filter volume, loss and cost, the viable LCL filter design that minimizes the total required inductance is selected. The proposed design procedure is applied to a 30 kW, 20 kHz 3-level unidirectional rectifier, employed in a modular DC fast charger. The performance of the selected optimal design, featuring equal grid-side and converter-side 175 μμH inductors and 15 μμF capacitors, is verified experimentally on an active front-end prototype, both in terms of harmonic attenuation capability and current control dynamics. A current total harmonic distortion (THD) of 1.2% is achieved at full load and all generated current harmonics comply with the applicable harmonic standard. Moreover, separate tests are performed with different values of grid inner impedance, verifying the converter control stability in various operating conditions and supporting the general validity of the proposed design methodology.

The response of a neuron when receiving a periodic input current signal is a periodic spike firing rate signal. The frequency of an input sinusoidal current and the surrounding environment such as background noises are two important factors that affect the firing rate output signal of a neuron model. This study focuses on the phase shift between input and output signals, and here we present a new concept: the agility of a neuron, to describe how fast a neuron can respond to a periodic input signal. In this study, we derived three agility score functions for the balanced leaky integrate-and-fire model, the Hodgkin-Huxley model, and the Connor-Stevens neuron model. By applying the score of agility, we are capable of characterizing the surrounding environment; once the frequency of the periodic input signal is given, the actual angle of phase shift can then be determined and, therefore, different neuron models can be normalized and compared with each other.

This paper shows two approaches to determine the battery impedance of battery cells or battery modules when used in a reconfigurable battery system (RBS) or in any type of modular multilevel converter (MMC) for electric drive applications. A generic battery model is used and the concepts of the recursive time and frequency-domain parameter extraction, using a current step and an electrochemical impedance spectroscopy, are explained. Thus, it is shown and demonstrated that the balancing current of neighboring cells/modules ,when in parallel operation, can be used, similar to the time-domain parameter extraction utilizing a current step, to determine the battery parameters. Furthermore, it is shown and demonstrated that a part of the inverter can be used as variable AC voltage source to control a sinusoidal current through the motor inductances of the drive train, which can be injected to the inserted battery cells/modules of an adjacent phase to perform an on-board impedance spectroscopy. Using either of the two presented approaches, the individual battery impedances can be easily determined, yielding the state of health (SOH) and the power capability of individual battery cells/modules. Nonetheless, the analyzed approaches were just considered to be applied at machine standstill, which is not suitable for grid-tied applications.

The primary objective of the power sector is to generate power to meet the power demand as per the necessity at the convenient locations, then transmitting and distributing to distinct load centers commemorating the quality and fidelity of the supply with reasonable tariff. This paper fixates over the alleviation of various power quality (PQ) issues in a PV-SOFC integrated grid system by the realization of sinusoidal current control strategy (SCCS) based simulation analysis of Unified Power Quality Conditioner (UPQC) using MATLAB R2016a incorporating different loads (linear and non-linear). A time domain control technique, SCCS endorsed on transitory PQtheory has been adopted for performance evaluation of the UPQC in PV-SOFC integrated grid system. The UPQC so carried out is to lessen the harmonic factor and further so as to offset the complex power unsettled to their unambiguous and reckless exercises. The recommended approach confirms drawing of sinusoidal quantities from the source

This paper proposes a control system for the single-phase Three-Ports Active Neutral- Point-Clamped (ANPC-3P) converter, which can inject a sinusoidal current into the grid, balance the neutral point voltage, and regulate the energy storage system (ESS) current with reduced low-frequency ripple. Despite other applications, ANPC-3P inverter can be used in grid-tied renewable generation to allow the simultaneous connection of a photovoltaic (PV) energy source and an ESS to the AC grid. The ESS is connected directly to the inverter circuit without any auxiliary DC-DC converter, but due to the DC bus pulsed power, it can be subjected to low-frequency current ripple. This undesired current ripple is difficult to filter and can lead to shorter battery life. A control system based on well-known controllers is analyzed and designed. Theoretical analysis is validated experimentally using a single-phase 1-kW prototype.

Fast and reliable initial rotor position detection is essential for restarting sensorless permanent magnet synchronous motors (PMSMs) in free-running condition. In this article, a fast initial rotor position estimation method for low-speed free-running motor is proposed, which utilizes a combined sinusoidal current and square-wave voltage injection method. The sinusoidal current is imposed into the estimated d -axis to magnify the magnetic saturation effect. The amplitudes of the d -axis current caused by injected square-wave voltage are then accumulated. The large difference of the two integrated signals for positive and negative d -axis currents can be reliably used to identify the rotor polarity. Meanwhile, in low-speed free-running stage, the change of saturation degrees introduced by the injected sinusoidal signal does not affect the position estimation accuracy. Moreover, even if the sinusoidal current signal is injected in the incorrect d -axis, the resultant torque is small and unexpected rotation of the rotor is prevented. Its influence on the free-running motor is negligible, due to the combined injection with continuously online updated estimated rotor position by high-frequency square-wave voltage injection during the polarity identification process. Finally, the effectiveness of the proposed method is investigated on a 1.5 kW interior PMSM test platform.

The novelty behind the research in this paper is to investigate the Super Twisting Sliding Mode Controller (ST-SMC) for efficiently injecting both active and reactive power under normal and abnormal operating conditions for a three-phase grid-connected photovoltaic (PV) system. The ST-SMC is aimed to inject sinusoidal current to the grid with low Total Harmonic Distortion (THD), to avoid chattering with easy real implementation, and to enhance the quality of disturbance rejection and sensitivity to parameter variation. The test under normal conditions includes initialization, steady state behavior, dynamic behavior, and interrupting the injection of acting and reactive power while the abnormal conditions consists of voltage sag, voltage swell, frequency variation, DC-link variation, and inclusion of 5th harmonics, etc. The phase lock loop used for synchronization is based on a synchronous reference frame that works well under distorted grids and nonideal. Automatic code is generated in PSIM 9.1 for hardware implementation in the DSP board TMS32F28335 from Texas Instruments while code composer studio 6.2.0 is used for debugging. The real time testing is executed using Typhoon Hardware in Loop (HIL) 402 device on the DSP board. The results authenticate the fastness, effectiveness, and robustness for both steady state and dynamic behavior under various scenarios of the designed controller.

The tuning of weighting factor has been considered as the most challenging task in the implementation of multi-objective model predictive control (MPC) techniques. Thus, this paper proposes an artificial intelligence (AI)-based weighting factor autotuning in the design of a finite control set MPC (FCS-MPC) applied to a grid-tied seven-level packed U-cell (PUC7) multilevel inverter (MLI). The studied topology is capable of producing a seven-level output voltage waveform and inject sinusoidal current to the grid with high power quality while using a reduced number of components. The proposed cost function optimization algorithm ensures auto-adjustment of the weighting factor to guarantee low injected grid current total harmonic distortion (THD) at different power ratings while balancing the capacitor voltage. The optimal weighting factor value is selected at each sampling time to guarantee a stable operation of the PUC inverter with high power quality. The weighting factor selection is performed using an artificial neural network (ANN) based on the measured injected grid current. Simulation and experimental results are presented to show the high performance of the proposed strategy in handling multi-objective control problems.

This paper presents a radial basis function network (RBFN) controller-based three-phase boost-type Vienna rectifier for a grid-tied wind energy conversion system. Boost-type Vienna rectifier is an ac/dc converter characterized by high power density and improved power factor in addition to maintaining a sinusoidal current with low total harmonic distortion at the input side. Such converter systems find its utility and application related to unidirectional power flow, such as data centers, telecommunication systems, and more appropriately for wind energy conversion systems. This paper involves the implementation of an RBFN-based control strategy for Vienna rectifier to ascertain the ability of the proposed strategy to obtain enhanced performance of a wind energy conversion system. The choice of the RBFN for the control of the rectifier system stems from its inherent capability to ensure better dynamic control notwithstanding its capability to reduce the design complexities during the network training phase. Simulation is carried out using MATLAB Simulink for a 1-kW standalone and grid-tied wind energy conversion system. This paper involves carrying out the detailed analysis and results for different wind velocities under standalone and grid-tied conditions.

The paper presents a theoretical study and experimental results regarding an original, low cost actuator, with a simple design, that uses an active magnetic spring in order to generate vibration. The analysis performed in the paper shows that the differential magnetic spring is the best solution for replacing the classical elastic suspensions in vibration generators. Mathematical modeling enables the determination of the parameters that characterize the actuator operation in the frequency domain. The experimental results show that the vibrator has, practically, a linear characteristic for oscillations of the order ±3 mm in amplitude and has a resonance frequency of approximately 36.5 Hz. The proposed model can generate dynamic forces of up to 15 N for an input sinusoidal current of 0.1A (peak). The maximum force supported by the magnetic spring is 42 N.

The use of PFC rectifiers has assumed an increasingly preponderance, contributing in a decisive way to improve the power quality indices, since they allow to operate with sinusoidal current on the ac side and with controlled voltage on the dc side. In this paper is proposed a novel PFC rectifier that allows five levels of voltage. As noted in the paper, it presents a number of interesting advantages when compared to the conventional five level PFC rectifier, mainly because it requires less passive and active semiconductors to produce the different voltage levels and requires less hardware resources to implement the gate driver circuits. The proposed five level PFC (5L PFC) rectifier operates in boost mode and has a single dc link (although with a midpoint to achieve the various levels), being an important feature for applications in smart grids (e.g., smart electrical appliances and electric mobility chargers). The key topics of the 5L PFC rectifier are addressed and discussed based on the analysis of the principle of operation. As current control strategy it was adopted the model predictive control. Experimental results in steady and transient state were considered for an effective validation of the 5L PFC rectifier, verifying the operation with: sinusoidal current on the ac side; multi level operation with five levels; controlled dc link voltage., FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017 and by ERDF - European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT, within project. Mr. Tanta was supported by FCT PhD grant with a reference PD/BD/127815/2016.

This paper proposed an improved control method for grid-connected voltage source converter (VSC), when the grid voltage consisted of the integer harmonics and inter-harmonics. Control object of the proposed control can be alternated to achieve the sinusoidal current or smooth output power, which enhances the operation adaption of VSC under the harmonically distorted grid. On the basis of a PI regulator in the fundamental current control loop, the novel control strategy was proposed with a supplementary controller which consisted of a prepositive high-pass filter and a modified proportional-derivative controller. In the proposed control, the inter-harmonics could be suppressed without detecting frequency, while the traditional resonator was effective in the premise of knowing the harmonics frequency. Also, the influence of control gain on the steady performance and the stability of VSC was analyzed, and the influences on the fundamental control caused by the proposed controller were also analyzed to verify the practicability of the proposed control strategy. Finally, the effectiveness of the proposed strategy was verified by the experiments.

The determination of Open Circuit Voltage (OCV) is required in order to successfully model electrode behavior, and a standard method for doing this is to charge and discharge a cell at very slow current rates while measuring both voltage and State of Charge (SOC). For example, scans at a rate of C/100 (needing 100 h to charge from empty to full) are often used, but faster scans lose accuracy because irreversible losses, including those due to transport phenomena and reaction kinetics, impact the voltage in rough proportion to scan rate. We develop perturbation methods to correct measurements at higher scan rates to make their accuracy comparable to results at slower scan rates. Perturbation corrections are given for cases in which current is scanned (e.g., at different constant C-rates) as well as when voltage is scanned (e.g., linear-sweep voltammetry). Sinusoidal scanning of either voltage or current is proposed to eliminate the discontinuities at scan reversal, increasing the accuracy of these methods. The analytic formulas given here can be combined with a regression analysis of data at multiple scan rates to determine not only the OCV but also other resistances in the electrode, and this is a goal of future work.

In this paper, we propose a numerical framework to study the shapes, dynamics, and stabilities of the self-localized solutions of the nonlinear wave blocking problem. To our best knowledge, blocking of the solitons in the marine environment has not been studied before in the existing literature. With this motivation, we use the nonlinear Schrodinger equation (NLSE) derived by Smith as a model for the nonlinear wave blocking. We propose a spectral renormalization method (SRM) to find the self-localized solitons of this model. We show that for constant, linearly varying or sinusoidal current gradient, i.e. d U ∕ d x , the self-localized solitons of the Smith’s NLSE do exist. Additionally, we propose a spectral scheme with a 4th order Runge–Kutta time integrator to study the temporal dynamics and stabilities of such solitons. We observe that self-localized solitons are stable for the cases of constant or linearly varying current gradient however, they are unstable for sinusoidal current gradient, at least for the selected parameters. We comment on our findings and discuss the importance and applicability of the proposed approach.

This paper presents a new dual-switch control structure for an ac/dc noninverting cascaded buck–boost power factor correction converter. The proposed converter operates at a discontinuous capacitor voltage mode providing an inherent high-power factor and a zero voltage turn-off switching. Additionally, the proposed control structure enables for a nondistorted sinusoidal current for a wide range of output voltage levels. Unlike the conventional methods, a mode detector is not required and consequently there is no hard transition between buck and boost modes. Although both converter switches are controlled, only one feedback control loop is required to obtain the desired power flow at a unity power factor. The principle of operation, theoretical analysis, simulation, and experimental results of a 1.6-kW prototype grid-connected converter are presented. The results confirmed the validity of the proposed system under various operating conditions.

this paper, a single-stage grid-connected flyback microinverter is proposed. The proposed flyback microinverter has some advantages such as high voltage gain, high efficiency, low cost, small size, simple control and high power factor. The proposed system is used to connect the PV panel to the grid with achieving maximum Power Point Tracking (MPPT) control. The converter operates in DCM to inject a sinusoidal current into the grid with unity power factor. A complete system has been simulated using PSIM program. The simulation results are obtained to validate the system. Keywords-Stage, grid-connected, Microinverter, Flyback, DCM, MPPT.

A technique to determine the parameters of a shielded busbar with a rectangular monolithic bus at steady-state conditions under sinusoidal current is suggested. The resistances, inductances, magnetic inductions, induced screen current, and bus voltage are calculated taking into account the sinusoidal current frequency and bus and screen materials. The developed technique is based on electromagnetic field equations, which can be programmed using the Mathcard software for engineering calculations of the busbar parameters during computer-aided design of busbars. The validity of the technique is corroborated by the satisfactory agreement between the results of resistance and inductance calculations and the results obtained using the Elcut computer simulation program.

This paper presents a new power electronic interface based line-commutated inverter (LCI) for dc power injection to the grid. The proposed system involves a simple power electronic converter and controller interface using a single-phase LCI. The controller has been developed that can inject a high quality sinusoidal current to the utility grid from the dc source. By this means, ac side harmonic filters and the harmonic cancellation technique are eliminated. The proposed system facilitates controlling the injected current with a controllable power factor of operation. The complete system has been modeled in MATLAB/Simulink and tested experimentally with the laboratory prototype. Finally, the simulation and the experimental results show good performance of the proposed LCI technique. The total harmonic distortion (THD) of the injected currents for the different power factors and reference current signals is achieved less than 5%, which meets the grid-connected standards. The proposed single-phase LCI inverter system is a good alternative to the dc power transfer from renewable energy sources (photovoltaic, fuel cell etc.) to the utility grid.

In general, there are two main classifications in matrix converters. The most common known type is conventional matrix converter (CMC) or direct matrix converter (DMC). The other type is indirect matrix converter (IMC). A brief review for modulation strategies are provided in this work for modulation strategies in IMC. There are several popular modulation methods for IMC such as carrier-based modulation and space vector modulation (SVM). A sinusoidal current waveform is produced on the input and output sides to implement the modulation method. In the conclusion the modulation methods will compared based on performance, theoretical complexity, and some other parameters.