Direct Control Research Articles

Theoretical aspects of the intangible assets system in the process of enterprises strategic management: definition, characteristics, classifications

The article studies theoretical aspects of the intangible assets system in the process of enterprises strategic management. In particular, it highlights the points of view of Russian and foreign scientists regarding the definition of the intangible assets concept. The author’s definition of intangible assets as a set of a company’s resources and assets, which do not have a physical form, are used in the process of creating goods (services) for a long period of time (more than a year), are involved in the creation of values that provide a company a competitive advantage in the market and meet the requirements of identifiability (an object separation from other resources), the presence of future profits from their use, and direct or indirect control by a company. The basic criteria of intangible assets are identifiability, control over them, and the presence of future profits from their use. Despite the variety of available approaches in foreign literature to the intangible assets classification, in our opinion, the classification, which includes human, customer, and structural assets (capital), is fundamental. The article concludes that foreign authors shift their research focus from organizational (structural) intangible assets, such as corporate culture, organizational structure, and brand, to consumer and attitudinal (customer) ones, such as the level of customer satisfaction and loyalty and relationships value. The methodological approaches analysis to intangible assets assessment, the issues of their creation, modeling, and use by companies is a direction for further research.

Novel Direct Power Control Based on Grid Voltage Modulated Strategy Using Artificial Intelligence

Novel Direct Power Control Based on Grid Voltage Modulated Strategy Using Artificial Intelligence

Advanced directional beam control via holographic acoustic metasurfaces for multibeam scanning

Acoustic multi-beam leaky-wave antennas, designed with holographic metasurfaces, have great potential for beamforming by achieving directional beam control. We propose a planar holographic metasurface for beam steering using multi-beam acoustic radiation serving as high-gain acoustic leaky wave antennas. Based on the principle of holography, we designed a metasurface that adjusts its admittance in a sinusoidal pattern. This surface consists of periodic cylindrical holes with varying depth profiles. A monopole point source is positioned in the middle of the patterned surface, which generates surface waves on the modulated surface and emits acoustic leaky-wave radiation in the desired directions. The holographic admittance surface is designed to radiate an acoustic beam at a frequency of 20 kHz. Additionally, the concept was extended to generate multi-beam scanning for forward leaky-wave radiation in the holographic process. In this research, we employed 3D additive manufacturing to create acoustic holograms, manipulating surface admittance variation at a resolution smaller than the wavelength. The experimental measurements aligned well with both the theoretical and numerical analysis findings, affirming the effectiveness of the proposed technique. The methodology exhibits broad applicability across various domains, including sonar, ultrasound imaging, waveform manipulation, and acoustic communication.

Creating Future Stations: The Application of Large Generative Models in Metro Design

New technologies, including the use of generative models, are beginning to actively influence design decisions in the decoration of metro stations. The study of the possibilities of using generative artificial intelligence as an art design tool in the decoration of metro stations is relevant, because it can significantly accelerate the design process, reducing time and labour costs for the development and optimization of projects. The novelty of the article lies in the fact that for the first time the process of interaction between the designer and software and hardware of large generative models is considered in detail on the example of designing the interior of a metro station on the theme “ocean”.The problem of creation of original design project in conditions of generative models at the moment is not solvable without direct control on the part of a human, as this technology, for lack of human perception, first of all orientate on expressive means contained in training databases. Therefore, when designing metro stations using generative models, images generated through text often lose the semantic and emotional meanings that the designer put into them. As a result, the generated design project does not fully conform to the designer’s intent and requires further manual adjustment and optimization. Thus, as long as there is a need for conscious and purposeful communication of ideas and feelings through art and design, the problem of endowing a work with meaning using generative models will require human involvement.At the same time, it should be noted that in the artist’s work, the use of generative pre-trained transformers is manifested in the ability to easily create realistic visual effects, to execute images in different styles, focusing on the creative individual manner of famous masters, and to improve design ideas. The advantage of this technology is that it can reduce the designer’s workload while improving the efficiency and accuracy of the design.

Direct Power Control of BDFRG Based on Novel Integral Sliding Mode Control

Direct Power Control of BDFRG Based on Novel Integral Sliding Mode Control

Comparative analysis of direct coupling and MPPT control in standalone PV systems for solar energy optimization to meet sustainable building energy demands

Solar energy, a prominent renewable source, has reached an installed capacity of 71.78 GW in India. This research explored the load demands of the computer center at an engineering college in Tanjore, Tamil Nadu, India. The computer center at the engineering college has an annual energy requirement of 260,552 kWh/Year. Consequently, the research focused on the planning and implementation of a standalone photovoltaic (SAPV) system, assessing it against the institution's total annual energy consumption. The performance ratio and losses of the SAPV system with both direct coupling and an MPPT charge controller was compared. This comparative analysis aimed to evaluate the efficacy of two solar photovoltaic control methods—SAPV direct coupling and Maximum Power Point Tracking control—in optimizing energy harvesting from solar panels.

Cold autoantibody interference in pretransfusion testing and its resolution: a case report

We report a case of cold autoantibody detected in a 69-year-old gentleman diagnosed with chronic lymphocytic leukemia and cold autoimmune hemolytic anaemia. Pretransfusion testing showed panagglutination in ABO grouping, antibody screening and identification, with positive direct antiglobulin test (DAT) and positive control cells. A cold autoantibody was suspected, however, the test using a prewarm method and washed RBC with warm saline failed to resolve it. Further tests using DTT-treated cells resolved the grouping as AB RhD positive and DAT as positive with anti-C3d only (control negative). Cold autoadsorption was done and repeated antibody screening using cold-autoadsorped plasma was negative, excluding the presence of alloantibody. The cold-agglutinin titer was >1028 having a wide thermal range. Crossmatching using cold autoadsorped plasma with the AB-positive donor blood was compatible and the patient was transfused safely. For such cold autoantibody cases, an extensive immunohematological workup is required to exclude underlying alloantibody for transfusion safety and efficacy. Bangladesh Journal of Medical Science Vol. 23 No. 04 October’24 Page : 1238-1242

Sliding mode-based direct power control of unified power quality conditioner

The Unified Power Quality Conditioner (UPQC) is a promising solution for mitigating multiple Power Quality(PQ) issues in distribution systems, including harmonics, poor power factor, voltage sag/swell and voltage imbalance. The conventional Sliding Mode Controller (SMC) in UPQCs suffers from wide switching frequency variations, chattering problems, and inherent active and reactive power coupling. This study proposes a nonlinear control method, Sliding Mode-based Direct Power Control (SMC-DPC), for the simultaneous regulation of the shunt and series compensators in a UPQC. By optimizing voltage vector selection based on real-time power errors, the proposed method effectively mitigates chattering, and reduces switching frequency variations, and ensures precise tracking of instantaneous active and reactive powers even in the presence of coupling effects. The proposed approach simplifies the system design and improves steady state and dynamic power tracking. The simulation results in MATLAB Simulink® on a 20 kVA system demonstrate that the proposed method achieves a source current THD of 1.52%, compared to 2.31% for conventional SMC and 5.11% for linear controller. Furthermore, the method is robust to grid parameter variations and demonstrates satisfactory performance in both strong and weak grids. In weak grids, the proposed method reduces the line losses by 13.71% and 14.54% compared to SMC and linear controller respectively. The reported results comply with international standards such as IEEE-519 and IEC 61000-3-12, confirming effectiveness of SMC-DPC for enhancing PQ in distribution system.

Principle and pressure loss experiment of electro-hydraulic slide-rotary direction valve in single-pump and multi-motor hydraulic system

To better realize direction control of the single-pump double-motor hydraulic system and simplify the system, structure and principle of a six-position six-way direction control valve was proposed, which the valve spool has two motion modes: sliding and rotating. Using this valve, the inner and outer motors can work independently and simultaneously. The pressure loss of the valve was tested by building a transmission system, and the experiment results were compared with theoretical analysis. The results show that the performance of the valve working in left and right positions is better than that in meso-position, and the maximum pressure loss occurred in meso-position. Under the rated flow, the maximum pressure loss is 0.331 MPa. Then the characteristic curve of flow-pressure loss and the relationship of pressure loss among oil ports are obtained. In the same conditions, except that the oil inlet pressure loss in the meso-position is greater than the oil outlet pressure loss, the oil inlet pressure loss in the left and right positions are less than the oil outlet pressure loss, the pressure loss in the forward position is less than the pressure loss in the reverse position. The experiment verifies the correctness and feasibility of the structure and principle.

Spread or Splash: The Ubiquitous Role of Droplets in Mafic Explosive Eruptions

AbstractMagma fragmentation is an essential process driving explosive volcanic eruptions, generating a distribution of pyroclasts with characteristic shape and grain size. These characteristics are often used to inform on the energetics of magma fragmentation and the associated eruption style and intensity. However, a portion of these pyroclasts, droplets when still in the molten state, are likely to be generated through impact mechanisms (i.e., collisions), and subsequent secondary fragmentation (i.e., splashing). Here, we successfully apply and dynamically scale concepts and findings of liquid droplet impacts in engineering to magma fragmentation processes in volcanology. We compile and model physical data for two mafic melt compositions (kimberlite and basalt) and use specific eruption examples from Igwisi Hills, Kīlauea and Stromboli volcanoes to define composition‐specific impact dynamics. Pyroclast impact dynamics have a direct control on in‐conduit processes, eruption dynamics, and ash dispersal. For low viscosity mafic melts such as kimberlite and basalt, pyroclast impacts can lead to both splash and deposition on the conduit wall, resulting either in conduit clearing or conduit narrowing, respectively. In both cases, shifting the impact regime toward surface deposition will lead to an inexorable decay in explosiveness, potentially switching the eruption style to effusive behavior. This has direct consequences for the transport of volcanic ash at the surface and inferring magma fragmentation processes (e.g., energies) from the depositional record.

Integral-proportional derivative approach for brushless direct current motor speed control

Integral-proportional derivative approach for brushless direct current motor speed control

Direct torque control of a dual star induction generator based on a modified space vector PWM under fault conditions

Recent studies have shown that electrical systems in wind power conversion are subject to a 67 % failure rate, and conventional three-phase generators are considered to be the most sensitive to these faults. Induction generator current harmonics are a major source of torque ripples causing acoustic noise and vibrations. These ripples can progressively increase under faulty operating conditions. In six-phase machines, there is appearance of high harmonic currents in the air gap as space harmonics. Power electronic converters are also subject to faults, the most common being Short-Circuit (SC) and Open-Circuit (OC) faults. SC faults cause large peaks in the line currents, which trigger the protection devices, resulting in a complete shutdown of the production system. OC faults, on the other hand, cause imbalances in the phases, but the system remains in operation.Direct Torque Control (DTC) based on Space Vector Modulation (SVM) at constant switching frequency is an effective solution to tackle induction generator current harmonics. This paper proposes a DTC combined with a Proportional Integral Fuzzy Logic Controller (PIFLC) optimized by Particle Swarm Optimization (PSO) in order to overcome the problems of torque ripples. Furthermore, using Vector Space Decomposition (VSD) and the Modified Space Vector Pulse Width Modulation (MSVPWM) strategy, a significant reduction of harmonics in the air-gap can be achieved.Simulations were carried out under MATLAB/Simulink, and the results obtained demonstrate the superiority of the proposed DTC-PIFLC-PSO controller in terms of robustness against wind speed variations and under faulty switch conditions in the power converter of the Dual Star Induction Generator (DSIG) generator. In addition, a comparative study with the classical PI controller is presented to show the effectiveness of the DTC-PIFLC-PSO controller against faults with a significant reduction in the Total Harmonic Distortion (THD) during both faulty and non-faulty conditions.

Geothermal use of groundwater in tunnels combined with direct passive road surface temperature control

Geothermal use of groundwater in tunnels combined with direct passive road surface temperature control

Enhanced direct torque control based on intelligent approach for doubly-fed induction machine fed by three-level inverter

This paper presents an adaptive neuro-fuzzy inference system (ANFIS) based on 24 sectors direct torque command (DTC) for a doubly-fed induction machine (DFIM) by using a 3-level neutral point clamped inverter. The DTC approach is used in this paper with 24 sectors based on the ANFIS regulator to minimize the torque fluctuations, flux fluctuations, and stator stream THD (Total Harmonic Distortion) of the DFIM drive. The composed technique is accomplished by replacing the hysteresis controllers of the flux and torque with the ANFIS controller. On the other hand, the results of the designed approach based on ANFIS controls were obtained compared to the traditional approach that uses usual controls, as MATLAB was used to realize these approaches in different working conditions. In all tests, the designed method shows improved performance in minimizing torque and flux undulations while reducing the THD of the stator stream. These results highlight the extent of efficiency, high competence, and effectiveness in improving machine features compared to the conventional approach, where the designed approach minimized the THD of current by ratios of approximately 77.50%, 48.34%, 75%, and 81.43% in all tests. Also, the torque undulation value was reduced by 30%, 39.24%, 31.94%, and 59.31% in all tests compared to the DTC. The designed approach minimized the speed overshoot compared to the DTC by percentages estimated at 98.83%, 97.11%, 96.75%, and 95.56% in all tests. These percentages demonstrate the high efficiency and effectiveness of the 24 sectors DTC-ANFIS compared to the conventional approach in improving the features of the control system, making it a promising solution in all electrical fields in the future.

ANN-Based Improved Direct Torque Control of Open-End Winding Induction Motor

ANN-Based Improved Direct Torque Control of Open-End Winding Induction Motor

ID: 309438 Real-World Outcomes Using DBS Systems With Directionality and Multiple Independent Current Control: USA Experience

ID: 309438 Real-World Outcomes Using DBS Systems With Directionality and Multiple Independent Current Control: USA Experience

Nonlinear Behavior and Transient Stability of Grid-Following Converters Using Direct Power Control Under Weak Grid

Nonlinear Behavior and Transient Stability of Grid-Following Converters Using Direct Power Control Under Weak Grid

Adaptive Neural Control for Hysteretic Nonlinear Systems With Hysteresis Neural Direct Inverse Compensator and Its Application.

Aiming at high precision control for a class of hysteretic nonlinear systems, a new hysteresis direct inverse compensator-based adaptive output feedback control scheme is designed in this article. First, a novel long short-term memory neural network (LSTMNN)-based hysteresis inverse compensator is established to compensate the asymmetric hysteresis nonlinearity, where the LSTMNN is used as the prediction mechanism for model operator weights, rather than the overall mapping of hysteresis input and output. Second, by designing the modified high-gain K-Filter states observer and the error transformed function, the unmeasurable states are estimated with arbitrarily small estimation error and the prespecified tracking performance is achieved. Lastly, the biconical dielectric elastomer actuator (DEA) motion platform is constructed. Then, the effectiveness of the proposed LSTMNN-based hysteresis inverse compensator and control scheme are verified on the experimental platform. The experimental results illustrate the effectiveness and advantages of proposed control scheme.

Acoustic Noise Mitigation in Slip Angle Controlled DTC of Open-End Winding Induction Motor Drive Using Dual Randomized AISPWM for EV Application

Low vibration and acoustical noise as well as effective DC link usage are the demands of industries and Electric Vehicles (EV). Direct Torque Control (DTC) of Induction Motors (IMs) meet the EV and other modern industry requirements. Still, flux as well as torque swings lead to higher acoustical noise. Consequently, EVs as well as working place noise have become major concerns, affecting the health of individuals. Efficiency of dc link use is improved by Space Vector Pulse Width Modulation (SVPWM). Yet, SVPWM is not efficient in lowering acoustical noise. Different RPWM techniques can lower acoustic noise. Still, the lower degree of randomisation makes the noise reduction difficult. This work presents a Hybrid Dual Random PWMs (HDRPWMs) based Alternate Inverter Switching (AIS) strategy for Slip-Angle Controlled Direct Torque Control of an Open End Winding IM Drive (OEWIMD). This technique is aimed to lower the acoustical noise for EVs. The intended PWMs seek to show how well HDRRPWMs distribute the acoustical noise spectra in contrast to conventional techniques.

Improved Performance of the Permanent Magnet Synchronous Motor Sensorless Control System Based on Direct Torque Control Strategy and Sliding Mode Control Using Fractional Order and Fractal Dimension Calculus

This article starts from the premise that one of the global control strategies of the Permanent Magnet Synchronous Motor (PMSM), namely the Direct Torque Control (DTC) control strategy, is characterized by the fact that the internal flux and torque control loop usually uses ON–OFF controllers with hysteresis, which offer easy implementation and very short response times, but the oscillations introduced by them must be cancelled by the external speed loop controller. Typically, this is a PI speed controller, whose performance is good around global operating points and for relatively small variations in external parameters and disturbances, caused in particular by load torque variation. Exploiting the advantages of the DTC strategy, this article presents a way to improve the performance of the sensorless control system (SCS) of the PMSM using the Proportional Integrator (PI), PI Equilibrium Optimizer Algorithm (EOA), Fractional Order (FO) PI, Tilt Integral Derivative (TID) and FO Lead–Lag under constant flux conditions. Sliding Mode Control (SMC) and FOSMC are proposed under conditions where the flux is variable. The performance indicators of the control system are the usual ones: response time, settling time, overshoot, steady-state error and speed ripple, plus another one given by the fractal dimension (FD) of the PMSM rotor speed signal, and the hypothesis that the FD of the controlled signal is higher when the control system performs better is verified. The article also presents the basic equations of the PMSM, based on which the synthesis of integer and fractional controllers, the synthesis of an observer for estimating the PMSM rotor speed, electromagnetic torque and stator flux are presented. The comparison of the performance for the proposed control systems and the demonstration of the parametric robustness are performed by numerical simulations in Matlab/Simulink using Simscape Electrical and Fractional-Order Modelling and Control (FOMCON). Real-time control based on an embedded system using a TMS320F28379D controller demonstrates the good performance of the PMSM-SCS based on the DTC strategy in a complete Hardware-In-the-Loop (HIL) implementation.