Search Results (1,509)

The design of special induction motors for variable-speed drives in pumping systems is carried out using the Design of induction machines for adjustable-speed drives (DIMASDrive) software, based on the motor efficiency criterion. The quality of a variable-speed drive is fully determined by an innovative criterion of equivalent costs, which takes into account not only the cost and energy efficiency of the drive, but also the costs of compensating for reactive power and distortion power, which characterize the drive’s energy and electromagnetic compatibility with the grid. The MATLAB program enables the calculation of the innovative criterion of the drive’s reduced costs. Currently, the cost component of distortion power compensation is not taken into account in the reduced cost criterion; consequently, the quality of the drive in monetary terms is determined incompletely and is underestimated. A method is proposed for calculating this component and incorporating it into the reduced cost criterion. The presented results were obtained entirely through simulations conducted using validated software. Experimental studies of the prototype will provide the final answer regarding the solution. Full article

Direct Torque Control (DTC) for induction motors (IMs) is an advanced method derived from Field-Oriented Control (FOC). In DTC, a voltage source inverter (VSI) is employed to directly regulate the stator flux linkage and electromagnetic torque through space vector modulation (VSM), where the optimal switching vector is selected for the VSI. Similarly to FOC, the stator flux and electromagnetic torque are independently controlled to deliver enhanced dynamic performance. However, DTC still suffers from certain drawbacks, such as slow transient response, limited dynamic performance, and high ripples in torque and flux. In this paper, an improved DTC method is proposed for a three-phase squirrel-cage induction motor. Specifically, a Type-2 fuzzy logic controller is employed to regulate both the stator flux and electromagnetic torque (T2FLC). The proposed method (FLCDTC) combines a three-level VSI with dual-band hysteresis (DBHW) switching to generate the gating signals for the insulated gate bipolar transistors (IGBTs). This approach effectively reduces the total harmonic distortion (THD) in torque and stator current, lowers the common-mode voltage (CMV), and enhances the overall motor performance. Simulation results under random noise distribution demonstrate the robustness of the proposed controller, even at low operating speeds. Finally, the effectiveness of the algorithm is validated in real-time through hardware-in-the-loop (HIL) implementation. Full article

Aiming at the problems that existing detection methods struggle to accurately identify early insulation faults of induction motors, are susceptible to interference, and have poor installation adaptability, a non-intrusive detection method for early insulation faults of induction motors based on a microstrip antenna array is proposed. Relying on the low-loss electromagnetic wave transmission characteristic of the heat dissipation hole at the tail of the induction motor, a four-element microstrip antenna array with multiple narrow beams and dual detection frequencies is designed, with the detection frequencies accurately set at 1.14 GHz and 2.23 GHz, which effectively avoids the motor operation noise frequency band (≤300 MHz) and the strong interference frequency band of mobile base stations (900 MHz, 1.8 GHz, 2.4 GHz). Utilizing the high gain and strong directivity of the array antenna, the accurate extraction and amplification of weak electromagnetic wave signals from early insulation fault discharge penetrating through the heat dissipation hole are realized. The full-dimensional simulation design of the antenna array is completed by using HFSS electromagnetic simulation software, and an industrial-grade experimental platform is built to carry out multi-condition verification experiments. The results show that the proposed detection system can realize non-intrusive, non-stop, and non-disassembly identification of early insulation discharge faults in induction motors, with a fault recognition rate of 94% for single faults and 90% for composite faults, and the average signal-to-noise ratio reaches 31.6–35.2 dB. Even under strong industrial electromagnetic interference, the recognition rate remains above 85%. This method overcomes the problems of traditional methods such as severe noise interference, difficult installation, and inability to monitor online, providing a high-efficiency scheme for real-time insulation state monitoring of industrial induction motors with good engineering application value. Full article

Sepsis is a life-threatening syndrome driven by a dysregulated host response to infection and is frequently complicated by sepsis-associated encephalopathy (SAE), which contributes to long-term cognitive and neuropsychiatric sequelae. Despite advances in critical care, effective targeted therapies for SAE remain limited. Aquaporin-4 (AQP4), the predominant astrocytic water channel, plays a central role in cerebral water homeostasis, neuroinflammatory signaling, and blood–brain barrier integrity, suggesting its potential involvement in sepsis-induced cerebral dysfunction and neurorepair processes. Polymicrobial sepsis was induced in C57BL/6J mice using the cecal ligation and puncture (CLP) model. AQP4 activity was pharmacologically modulated through either inhibition or facilitation following sepsis induction. Disease severity was assessed using physiological parameters and a modified murine sepsis score. Neurological outcomes were evaluated through standardized behavioral tests assessing locomotor activity, motor coordination, cognitive performance, and depressive-like behavior. Neuroinflammatory and neuronal changes were examined by immunohistochemical analyses of microglial activation (Iba1), astroglial reactivity (GFAP), neuronal integrity (NeuN), and AQP4 expression. Compared with AQP4 facilitation, pharmacological inhibition of AQP4 was associated with a more favorable clinical recovery profile, reflected by lower sepsis severity scores and a more favorable body weight trajectory during the recovery phase. Behavioral analyses demonstrated preserved cognitive function, enhanced motor coordination, and reduced depressive-like behavior in AQP4 inhibitor-treated mice compared with animals receiving AQP4 facilitation. At the histological level, the inhibitor-treated group showed lower microglial and astroglial activation and better preservation of neuronal markers than the facilitator-treated group, whereas AQP4 facilitation exacerbated neuroinflammatory responses and neuronal alterations. These findings highlight a dual, context-dependent role of AQP4 in sepsis-associated cerebral dysfunction. These findings suggest that AQP4 modulation influences sepsis-associated cerebral dysfunction in a context-dependent manner. Within our experimental design, AQP4 facilitation was associated with worse outcomes, whereas AQP4 inhibition was associated with a comparatively more favorable neurobehavioral and histological profile. Full article

Three-phase induction motors account for nearly two-thirds of industrial electricity consumption, making accurate parameter identification essential for efficiency optimization, predictive maintenance, and digital twin calibration. This paper introduces the stochastic spheric navigator algorithm (SSNA) for estimating the equivalent circuit parameters (stator and rotor resistances, leakage reactances, and magnetizing reactance) of induction motors by minimizing the normalized squared error between manufacturer-provided torque characteristics (starting, peak, and full-load) and their analytical counterparts derived from the steady-state Thévenin model. The SSNA employs an adaptive spherical search mechanism with a decaying radius schedule that progressively narrows the exploration neighborhood, enabling a balanced transition from global exploration to local refinement. Validated on 5 hp and 25 hp motors against the genetic algorithm (GA), particle swarm optimizer (PSO), hybrid GA-PSO, and sine–cosine algorithm (SCA), the SSNA demonstrates distinct advantages. For the 5 hp motor, it achieves the lowest errors in maximum torque ($1.34\times {10}^{-4}\%$) and full-load torque ($5.08\times {10}^{-4}\%$). For the previously unreported 25 hp motor, the SSNA yields an objective function value of $4.68\times {10}^{-12}$—six orders of magnitude lower than the SCA—and reduces magnetizing reactance estimation error from 46.55% (SCA) to 16.18%. Statistical analysis over 100 independent runs reveals that the SSNA uniquely combines the lowest minimum (best) value, the lowest maximum (worst) value, and the lowest standard deviation, demonstrating superior accuracy, reliability, and consistency. These results position the SSNA as a highly competitive optimization framework for induction motor parameter identification, with particular suitability for applications demanding high precision and robust performance. Full article

Inspired by the key hole concept in micro-surgery, we developed a “magnetic key hole concept” for basic studies of localized characteristics of soft magnetic laminations (electric steel, Fe-based amorphous ribbon) under exactly defined conditions of induction B(t). A material sample of 50 cm length and 10 cm width is magnetized in a novel multi-frequency SST that allows for exact sinus up to 10 kHz. A priori, the tester offers global results for permeability µ_G, power function p_G(t) and total loss P_G, as averaged over the entire sample material. But beyond that, a so-called Experimental Window (EW) offers additional information on local characteristics, as determined in a small central “key hole” region of defined magnetization. Here, a scanning adapter is mounted to study localized crystallographic features of the grain structure, as well as inhomogeneities, like failures, structure modifications, or specific technological treatment. Out of several types of sensor units a linear motor drive takes up a specific one within little manual effort. Already-developed sensor concepts concern the local tangential field, permeability, power, loss, and local widths of main domains and spike domains. The paper discusses several examples of analyses. Full article

The intense low-frequency magnetic field generated by the Electromagnetic Aircraft Launch System (EMALS) during operation poses a serious EMI threat to electronic equipment within carrier-based aircraft nacelles. To address this, a three-dimensional transient finite element model of a long-primary double-sided linear induction motor is established. Using a quasi-static equivalent method, the 118 Hz magnetic field distribution inside and outside a typical engine nacelle is characterized. Results indicate that due to the skin depth significantly exceeding material thickness, the eddy-current shielding of the aluminum alloy nacelle is inadequate, producing internal field intensities that far exceed standard limits and directly threaten sensitive onboard electronics. Based on the magnetic shunting principle, a composite shielding strategy is proposed: applying a flexible high-permeability coating on the nacelle surface to attenuate the overall field, supplemented by local permalloy shields for core equipment. Simulation verification demonstrates that this approach reduces the internal field to safe levels. It achieves effective shielding performance while balancing engineering feasibility with lightweight requirements, providing a viable pathway for ensuring the reliable protection of carrier-based aircraft in intense electromagnetic environments. Full article

Switching losses make up for a notable portion of all losses in converter-supplied electric drives. Control algorithms such as Finite State Model Predictive Control (FSMPC) have tackled this issue in different ways; in particular incorporating a switching penalty to the cost function. This, however, results in an optimization problem with increased computational load, restricting the attainable sampling frequency for a given computing hardware. Recently, fast algorithms have been developed that reduce the computational load. However they cannot incorporate the switching penalty term. This paper explores a way around this problem for the particular case of stator current control of a five-phase induction motor. The proposal achieves fast computation even if a term for switching frequency reduction is present in the cost function. Experimental results show how stator current tracking performance is affected in both the torque producing plane and the harmonic subspace. Full article

This study addresses pressure regulation in an induction-motor-driven centrifugal fan and introduces two complementary novelties: a Softsign-PI controller that shapes the tracking error via a Softsign nonlinearity before PI regulation and a hybrid starfish optimization with a differential evolution (hSFOA-DE) scheme for automatically tuning the controller parameters. The approach is evaluated on an experimentally validated nonlinear fan–motor model and benchmarked against modern metaheuristics—starfish optimization algorithm (SFOA), animated oat optimization (AOO), electric eel foraging optimization (EEFO), differential evolution (DE), particle swarm optimization (PSO)—as well as classical tunings—Murrill-based 2-DOF PID, Tyreus–Luyben PID and Ziegler–Nichols PI. Statistical summaries and boxplots indicate superior central tendency with reduced run-to-run variability; fitness–evolution curves show faster convergence; and time-domain performance metrics confirm improved transient and steady-state behaviour. Objective function comparisons further show the lowest values of both the Zwe-Lee Gaing (ZLG) and integral of absolute error (IAE), supporting advantages in robustness and tracking accuracy of the proposed approach. These gains reduce overshoot and cumulative error, which can lessen throttling losses and actuator duty in fan/pump service, suggesting potential energy and maintenance benefits. Full article

This paper aims to improve the energy autonomy and the mechanical performances of an on-board drive chain for robotics. The energy autonomy improvement is performed by reducing electrical losses in the inverter. Electrical losses are reduced by decreasing the number of switching cycles per period of the inverter’s power semiconductor switches, while maintaining a low Total Harmonic Distortion (THD). These improvements are expected thanks to a new control strategy called Pre-Calculated Pulse Width Modulation (PC PWM). The principle of this new control strategy is that all the symmetries of an ideal three-phase voltage system are assigned to the real output voltage of the inverter. Then the switching instants of the inverter’s switches are determined off line, by means of Fourier’s analysis, so that the maximum number of successive harmonics is zeroed. This allows the optimal switching sequence to be predefined, thereby reducing unnecessary commutations of the power switches. The performance of the new method (PC PWM) is evaluated through detailed simulation studies and compared with the conventional method called Sinusoidal Pulse Width Modulation (SPWM). The simulation results show that despite the reduction in the number of commutations per period, the performance of the actuation chain has been significantly improved with PC-PWM (new technique). Indeed, for the same mechanical load, the PC-PWM method allows for a lower current, a shorter transient response time and a lower torque ripple than the SPWM method. Full article

Electric vehicle (EV) adoption in South Africa remains constrained by high upfront purchase costs, limited charging infrastructure, and policy uncertainty, creating a need for lower-cost and locally relevant pathways to transport decarbonisation. This study evaluates the feasibility of converting a legacy light commercial pickup platform from internal combustion engine (ICE) propulsion to battery-electric propulsion through integrated component sizing, longitudinal vehicle simulation, and techno-economic assessment. A retrofit architecture comprising a traction battery, inverter-controller, electric motor, and DC-DC converter was developed using first-principles vehicle dynamics and energy-demand analysis. The resulting configuration employed a 40 kW AC induction motor, an approximately 28 kWh battery pack, a 40–60 kW inverter with 60 kW peak capability, and a 0.75–1.2 kW auxiliary DC-DC converter. Simulation over a representative 1000 s drive cycle showed stable speed tracking, sustained vehicle motion over approximately 10 km, and peak battery currents exceeding 300 A during acceleration, while regenerative braking reduced net cumulative energy consumption relative to gross demand. The economic analysis indicated that the retrofit pathway yielded the lowest cumulative total cost of ownership over most of a 10-year horizon, with breakeven relative to the used ICE baseline occurring at approximately 3.4 years. Lifecycle analysis further showed that the retrofit configuration achieved the lowest combined production and operational carbon burden among the compared vehicle pathways. These findings indicate that ICE-to-EV retrofitting of legacy light commercial vehicles can provide a technically feasible, economically competitive, and environmentally advantageous electrification strategy for South Africa and comparable emerging markets. Full article

This article presents a case study of a program aimed at creating support networks among families of students with functional diversity (motor disability, ASD, DLD, intellectual disability, ADHD, CD) with the purpose of expanding their coping resources in the face of the chronic stress they experience, resilience and empowerment. The program was developed in a public school of infant and primary education in the Community of Madrid (Spain). The design of the program is based on the domains of quality of life. The development of the program followed a qualitative case study approach, framed within the critical participatory action research, and was structured in cycles of planning, action, observation and reflection. These cycles included face-to-face sessions with families, participant observation, collaborative dynamics to record what happened and what was expressed in the sessions, and the analysis of materials produced by the families themselves. In the case study, an inductive approach was used to analyze the collected content, guided by Schalock’s family-adapted quality of life model. The results show an increase in family involvement, a perceived improvement in emotional and practical support, and a greater involvement of families in decision-making and community awareness. It is concluded that placing the well-being of families at the center of educational action improves their stress coping skills, resilience and empowerment, strengths that have an impact on community cohesion and the sustainability of their children’s inclusion processes. Full article

The electrification of regional railway lines using battery-electric trains requires accurate simulation tools to support energy management and thermal control design. This paper presents an integrated dynamic simulation model of the traction system of a Hitachi Caravaggio ETR 521 regional train operating in battery-electric mode, developed in MATLAB/Simulink 2024b. The model incorporates all key drivetrain components, including a train reference generator, speed controller, motor controller, three-phase inverter, induction motor, a Kokam Co., Ltd. lithium-ion battery pack, and a detailed battery thermal management system. The proposed framework enables simultaneous evaluation of traction performance, battery state of charge (SOC) evolution, and thermal behavior under realistic conditions. To validate the model, simulations of the Treviso–Vicenza route were conducted under two scenarios: traction-only operation and operation with a 160 kW auxiliary load. Simulation results demonstrate that auxiliary loads significantly affect energy consumption and battery thermal behavior, with energy consumption increased by 50%. The results highlight the importance of integrating thermal effects into energy management and sizing decisions for battery-electric regional trains. The developed model provides a practical tool for optimizing battery sizing, thermal management strategies, and overall energy performance, supporting the planning and design of sustainable electric railway solutions. The modular MATLAB/Simulink architecture is designed to be route-agnostic; extension to other regional lines with different gradients, speed profiles, or extreme climate conditions (e.g., alpine routes or high-temperature regions) requires only updated route data and adjusted ambient boundary conditions, demonstrating the model’s broad applicability beyond the Treviso–Vicenza case study. Full article

This paper presents an analysis of the impact of sub-cycle voltage reductions (below 1 ms) on the operation of a slip-ring induction motor. Due to the specific design of the slip-ring induction motor and the presence of a separate rotor circuit, direct measurements of rotor currents and voltages are possible, enabling a more detailed analysis of the physical phenomena occurring in the machine. A series of experiments was conducted using the Profline 2100 device, which enables the generation of controlled sub-cycle voltage reductions. This made it possible to directly assess the influence of such disturbances on motor operation, particularly changes in stator and rotor currents, rotational speed, and electromagnetic torque pulsations. The electrical and mechanical parameters of the motor were also identified. The obtained data were used to develop a mathematical model and implement it in the MATLAB/Simulink environment, enabling qualitative reproduction of the observed phenomena. The main novelty of this work is the analysis of the electromagnetic response of a slip-ring induction motor to sub-cycle voltage reductions below 1 ms, supported by direct measurements in the rotor circuit. The resulting model, validated against measurement results, shows qualitative agreement with the experiments and enables a more detailed analysis of motor dynamics during sub-cycle voltage reductions, including phenomena that are difficult to capture experimentally. Full article

Background/Objectives: Ambroxol is a mucolytic agent widely used in the treatment of respiratory diseases; however, evidence in the literature indicates anti-inflammatory, analgesic, and immunomodulatory properties, suggesting potential for therapeutic repositioning. This study aimed to evaluate the analgesic and anti-inflammatory effects of ambroxol in an experimental model of osteoarthritis (OA). Methods: Adult male Wistar rats underwent OA induction on day zero (D0) by sodium monoiodoacetate (MIA) injection and were allocated into the following groups: Healthy, negative control (CTRL−), and groups treated with meloxicam (2 mg/kg) or ambroxol (10, 50, and 100 mg/kg). Treatments were administered orally (gavage) once daily for 28 days. Behavioral tests were performed, including rotarod, walkway gait analysis, weight-bearing, Von Frey, and Rat Grimace Scale assessments, along with radiographic and histopathological analyses and quantification of pro- and anti-inflammatory cytokines (IL-1β, IL-6, and IL-10). Results: Ambroxol treatment improved nociceptive parameters and motor function, reduced radiographic and histopathological scores, and showed performance comparable to meloxicam in several tests. There was a marked reduction in IL-1β and IL-6 levels, while IL-10 levels were lower in ambroxol-treated groups, suggesting early control of the inflammatory response. Conclusions: The results indicate that ambroxol exhibits antinociceptive and anti-inflammatory actions and suggest a potential chondroprotective effect, reinforcing its viability as a candidate for therapeutic repositioning in osteoarthritis. Further studies are required to more precisely elucidate its mechanisms of action, define optimal dosing and treatment duration, and support translation to clinical models. Full article