Changes In System Parameters Research Articles

INFLUENCE OF MINE-BLAST INJURY AND COMBAT STRESS ON THE STATE OF THE VEGETATIVE NERVOUS SYSTEM

Aim. In order to study the disorders of the autonomic nervous system as a result of mine-blast trauma and combat stress, as well as to analyze the dependence of the manifestation of these disorders on the age and duration of the injury, 62 people were examined. Materials and methods. The main group consisted of 37 servicemen with mine-blast trauma (MBT) and surgical interventions, and the control group consisted of 25 civilian men. The age of the subjects ranged from 18 to 45 years. The state of the autonomic nervous system was determined using ANS Analysis equipment and included three main parameters: resting heart rate, sympathetic nervous system parameters, and parasympathetic nervous system parameters. The significance of the difference between the groups of results was checked using the Mann-Whitney test, and the relationship between them, the age of patients and the time interval from the injury was checked using the Spearman rank correlation coefficient. Results. According to the results of the study, changes in the autonomic nervous system indices were absent in the group of civilians, while significant changes in the ANS indices in the group of servicemen with combat trauma were found for all three parameters: heart rate, sympathetic and parasympathetic autonomic nervous system indices. Also, in the group with MBT, a pronounced dissonance between the indicators of the autonomic nervous system was revealed: against the background of a significant increase in sympathetic status, a significant decrease in parasympathetic status was observed (179,0 (57,5; 309,0) vs. 13,0 (10,0; 28,0). Changes in the indicators of autonomic nervous system with combat trauma did not depend on the age of patients. Instead, there was a weak but statistically significant positive correlation between the duration of the injury and the parasympathetic nervous system: rs=0.325 (p=0.049). Therefore, the early use of a set of measures that increase the activity of the parasympathetic nervous system is logical. Conclusions. There were no changes in the autonomic nervous system parameters in the civilian group, but significant changes in the ANS parameters were found in the group of military personnel with combat trauma.

Analysis and circuit implementation of fractional-order memristive hyperchaotic system with enhanced memory

Abstract In this paper, based on the memory characteristics of fractional calculus, a new fractional-order memristor is proposed. Fractional-order memristor is a more accurate description of memristor, which has richer dynamic behavior and better memory performance. Which has a stronger memorizability compared to other fractional-order memristor by analyzing the pinched hysteresis loop area. Based on the above fractional-order memristor, a fractional-order memristive hyperchaotic circuit is designed, such system is analyzed by using the Lyapunov Exponents and the bifurcation diagrams. With the change of system parameters, the phase trajectory of the system expands and narrows, and the amplitude of the chaotic attractor also changes. In addition, double chaotic attractors and coexisting attractors are found under different parameters and initial values. Finally, the fractional order memristor and the fractional order memristor hyperchaos circuit are realized by analog circuit in Multisim.

Simulation of the Discharge of a Supercapacitor Storage Device during Current Stabilization in the Windings of a Multi-Section Magnetic System

Introduction. The magnetic systems of high power microwave generators, such as relati­vistic reverse wave lamps and klystrons, are powered with a direct current of up to 1 000 A from supercapacitor storage for several seconds. When designing power supplies for these magnetic systems, there is always necessary to determine the energy characteristics of the storage device. The analytical calculation of the characteristics is difficult, because of dynamic changes in some parameters of the magnetic system and storage device during current flow.Aim of the Study. The aim of the article is to create and experimentally test a mathematical model describing the process of powering a multi-section magnetic system with direct current from a supercapacitor storage device.Materials and Methods. The simulation takes into account the dynamic changes in the magnetic system parameters when current flows. The supercapacitor storage device is represented as a simple RC-circuit, the parameters of which are the nameplate data of its capacitance and internal resistance. The description of a storage device discharge process is based on the energy balance data. This model is implemented in the National Instruments LabView 2012 software package and has a user-friendly graphical interface. The simulation results were tested on equipment consisting of a power supply based on a supercapacitor storage device and two-section magnetic system.Results. The simulation results showed a good agreement with the experimental ones. According to the experiment results, the waveform of the current and voltage of the sto­rage device, and the maximum duration of current stabilization were close to the simulation results. At the same time, the nameplate data of the capacity and internal resistance of the storage device characterize well its real parameters, taking into account the peculiarities of working together with the current regulator and the pulsed nature of energy consumption.Discussion and Conclusion. The slight difference in the results is explained by the deviation of the actual parameters of the storage device from its passport data and by the diffe­rence in the temperature of the windings used in the experiment and simulation. The calculation of the energy characteristics of the storage device is performed on the basis of the energy balance, which allows scaling the load through adding any number of energy consumers with independent current stabilization in each.

System frequency response model and droop coefficient setting considering renewable energy participation in frequency regulation

The highly uncertain and uncontrollable power output of renewable energy sources (RES), when integrated into power systems at high penetration levels, reduces system inertia and introduces uncertain changes in system structure, parameters, and frequency response characteristics. This renders traditional frequency regulation analysis methods and frequency response models inapplicable, lacking a generalized model to describe renewable energy’s participation in frequency regulation. Thus, this paper proposes a method where RES utilize suitable means to reduce load, thereby contributing to frequency regulation. Furthermore, employing Virtual Synchronous Machine (VSM) technology, these renewable energy units emulate the inertia and droop characteristics of Synchronous Generators (SG), enabling their equivalent modeling alongside traditional generators within a single-machine aggregate model. An SFR (System Frequency Response) model integrating renewable energy’s frequency regulation has been established. This model enables the analysis of the relationships between the system’s equivalent droop coefficient and the frequency nadir, nadir time, and quasi-steady-state point. Furthermore, the required equivalent droop coefficients are proposed for various sending-end system capacities and operating conditions. Finally, the model’s validity and accuracy are confirmed through a modified WSCC 4-machine 10-bus system, offering theoretical underpinnings for stable system operation and optimized operational planning.

Solitary wave solutions, bifurcation theory, and sensitivity analysis in the modified unstable nonlinear Schrödinger equation

This study examines the modified unstable nonlinear Schrödinger model, a fundamental nonlinear physical model vital for depicting optical solitary wave solutions and their evolution in dynamic fiber optics. The propagation of waves in nonlinear dispersive media is of great significance, presenting new opportunities for data processing in communication systems and generating ultrafast light pulses. Applying a wave transformation reduces the nonlinear Schrödinger equation to an ordinary differential equation, and an extended direct algebraic method is used to derive various soliton solutions. The novelty lies in using this method to uncover various soliton forms, which are then explored through graphical representations in 2D, 3D, and contour plots. The phase portraits and bifurcation theory also qualitatively assess the undisturbed planar system. Sensitivity analysis under different initial conditions indicates how the soliton solutions adapt to changes in system parameters. The outcomes confirm that the presented approach effectively evaluates soliton solutions across diverse nonlinear models, contributing to the understanding of wave propagation in slightly stable and unstable media.

The Effect of Adding Generation Bus to the Short Circuit Current Level in Electrical Power System

The need for electrical energy is changing and increasing, requiring system flexibility always to be changed and developed. On the other hand, changes in the configuration of the electric power system due to the addition of components or sub-systems also change system parameters such as impedance or level of fault current (short circuit current). This paper presents a study of changes in the fault current caused by adding a new generating bus to an electric power system. This paper aims to determine the change in short-circuit current due to the addition of generators on new buses connected to existing buses to identify the most suitable location for adding these generators based on short-circuit current levels. Three-phase short circuit faults are simulated and analyzed on the IEEE 14 bus standard system using ETAP software with a base MVA 615 MVA. The addition of generators was carried out at five locations with varying generating capacities. The research results show that the short circuit current will change significantly when adding a generator bus to bus 13, with an average percentage change of 5,656%. The smallest change occurs when adding a generator to bus 2, with an average percentage change of 2,417%. The research results conclude that connecting a generator to a new bus linked to an existing generator bus (PV bus) is more effective than connecting it to a new bus associated with a load bus (PQ bus).

A Comprehensive Approach to Load Frequency Control in Hybrid Power Systems Incorporating Renewable and Conventional Sources with Electric Vehicles and Superconducting Magnetic Energy Storage

This study addresses the load frequency control (LFC) within a multiarea power system characterized by diverse generation sources across three distinct power system areas. area 1 comprises thermal, geothermal, and electric vehicle (EV) generation with superconducting magnetic energy storage (SMES) support; area 2 encompasses thermal and EV generation; and area 3 includes hydro, gas, and EV generation. The objective is to minimize the area control error (ACE) under various scenarios, including parameter variations and random load changes, using different control strategies: proportional-integral-derivative (PID), two-degree-of-freedom PID (PID-2DF), fractional-order PID (FOPID), fractional-order integral (FOPID-FOI), and fractional-order integral and derivative (FOPID-FOID) controllers. The result analysis under various conditions (normal, random, and parameter variations) evidences the superior performance of the FOPID-FOID control scheme over the others in terms of time-domain specifications like oscillations and settling time. The FOPID-FOID control scheme provides advantages like adaptability/flexibility to system parameter changes and better response time for the current power system. This research is novel because it shows that the FOPID-FOID is an excellent control scheme that can integrate these diverse/renewable sources with modern systems.

Theoretical Analysis of Viscoelastic Friction System Characteristics of Robotic Arm Brake Based on Fractional Differential Theory

In engineering practice, the nonlinear vibration effect can easily lead to chaos in the system, which will not only reduce the performance of the system but also lead to premature fatigue of components, control failure, and increased safety risks. In view of the core position of the robotic arm in modern industry, this study relies on the robotic arm brake system to explore the theoretical basis of integrated viscoelastic materials as a vibration isolation layer. By analyzing the dynamic characteristics of the friction braking system with fractional differential terms, it aims to provide a new perspective for understanding and controlling the chaotic phenomena of a class of nonlinear friction systems. Firstly, we construct a model of a friction system and analyze its dynamic characteristics in detail. The self-excited vibration of the system under disturbance is studied. The relationship between amplitude and frequency is calculated by a nonlinear approximate analytical algorithm, and the accuracy of this relationship is verified by a numerical algorithm. Then, we compare the differences between non-fractional systems and fractional systems. It is found that with the increase in the fractional order term, the vibration amplitude of the system decreases significantly, which helps to reduce the nonlinear characteristics generated by the friction system and narrow the range of unstable solutions. Secondly, we also study the influence of parameter coefficients on the amplitude–frequency characteristics and analyze the local static bifurcation characteristics through singularity theory. Finally, we study the dynamic bifurcation behavior under different parameter perturbations and find that the change in system parameters will lead to the alternation of periodic motion and chaotic motion.

Experimental model of systemic inflammation during acetaminophen toxicity

Acetaminophen is one of the most toxic drugs that can cause liver damage. At the same time, acetaminophen-induced liver failure is closely associated with the development of systemic inflammatory response syndrome. However, there is no drug aimed at suppressing the systemic inflammatory response. That is, this issue needs to be studied experimentally, but a model of systemic inflammation during acetaminophen overdose has not yet been obtained. Therefore, it was decided to develop an experimental model of systemic inflammation during acetaminophen overdose. The purpose of this study was to experimentally substantiate the semi-lethal dose for acetaminophen overdose in C57Bl/6 mice and to evaluate the readings of blood tests after administration of the drug. To determine the semi-lethal dose, male C57Bl/6 mice were intraperitoneally injected with “Ifimol” (Unique Pharmaceutical Laboratories, India) or acetaminophen solution (Sigma-Aldrich, USA) with a concentration of 14 mg/ml in different doses. When introducing “Ifimol”, it was not possible to achieve a semi-lethal dose. When administering a solution of acetaminophen, 50% mortality was recorded at a dose of 600 mg/kg body weight. After establishing a semi-lethal dose, the experimental group was administered an acetaminophen solution (Sigma-Aldrich, USA) with a concentration of 14 mg/ml at a dose of 600 mg/kg. The control group was injected with saline in an equivalent volume. On the second day, liver and peripheral blood samples were taken. Subsequently, hematological and biochemical blood tests and histological analysis were performed. Histological examination revealed centrilobular necrosis and disorganization of the liver structure. According to the biochemical blood test, the activity of aspartate aminotransferase, alanine aminotransferase, creatinine concentration, and the de Ritis coefficient differed statistically significantly (p 0.05) in the experimental group compared to the control group. Among the hematological blood test parameters, there were statistically significant differences in the number of leukocytes, platelets, as well as the absolute and relative content of granulocytes and lymphocytes. Thus, 48 hours after administration of a semi-lethal dose of acetaminophen, there were signs of damage to internal organs (liver, kidneys) and changes in immune system parameters, which are similar to components of systemic inflammation in humans.

Connecting Cell Structure and Current‐Dependent Environment Changes in CO2 Electrolysis to GDE Operation Regimes and Multi‐Cell Interaction

ABSTRACTConsecutive development of materials, components, and ultimately, devices does not appear to be a promising strategy in CO2 electroreduction because maintaining comparability and transferring results between idealized and application‐oriented systems proves challenging. A modular cell design and tracking cell conditions via sensors may be a solution. We displayed a strategy to characterize gas diffusion electrode operating regimes in a flow cell with regard to different current density ranges, as well as the impact of the flow gap design. We revealed strong interdependencies between cell components, their functions as well as individual cells when integrated into a stack. Expanding the scope and resolution of experimental data made new information on the change of system parameters in flow cells accessible.

Loss Model Control for Efficiency Optimization and Advanced Sliding Mode Controllers with Chattering Attenuation for Five-Phase Induction Motor Drive

This paper proposes firstly a Second Order Sliding Mode Control (SOSMC) based on a Super Twisting Algorithm (STA) (SOSMC-STA) combined with a Direct Field-Oriented Control (DFOC) strategy of a Five-Phase Induction Motor (FPIM). The SOSMC-STA is suggested for overcoming the shortcomings of the Proportional Integral Controller (PIC) and the Conventional Sliding Mode Controller (CSMC). Indeed, the main limitations of the PIC are the slower speed response, the tuning difficulty of its parameters, and the sensitivity to changes in system parameters, including variations in process dynamics, load changes, or changes in setpoint. It is also limited to linear systems. Regarding the CSMC technique, its limitation is the chattering phenomenon, characterized by the rapid switching of the control signal. This phenomenon includes high-frequency oscillations which induce wear and tear on mechanical systems, adversely affecting performance. Secondly, this paper also proposes a Loss Model Controller (LMC) for FPIM energy optimization. Thus, the suggested LMC chooses the optimal flux magnitude required by the FPIM for each applied load torque, which consequently reduces the losses and the FPIM efficiency. The performance of the optimized DFOC-SOSMC-STA based on the LMC is verified using numerical simulation under the Matlab environment. The analysis of the simulation results shows that the DFOC-SOSMC-STA guarantees a high dynamic response, chattering reduction, good precision, and robustness in case of external load or parameter disturbances. Moreover, the DFOC-SOSMC-STA, combined with the LMC, reduces losses and increases efficiency.

Numerical investigations on the performance of coupled NCL based passive heat removal system of an IPHWR

Passive heat removal systems (PHRS) are indispensable additional safety features in nuclear reactors to deal with station blackout (SBO) conditions. These systems are based on coupled natural circulation loops (C-NCL) connected in series configuration. Further, these system's design, operating conditions, working fluid, heat removal capacity, etc., are specific to the reactor type. In the present work, the operational performance of such first of a kind PHRS of 700 MWe Indian pressurized heavy water reactor (IPHWR) is investigated. For this purpose, a coupled two-phase NCL code is developed, validated and employed. This PHRS consists of two NCLs connected in HHVC-VHVC (horizontal heater and vertical cooler - vertical heater and vertical cooler) configuration. In this study, initially, the full power reactor thermal-hydraulic conditions are established, subsequently, the performance of the PHRS under SBO is investigated. The analyses demonstrated that the system is adequate to effectively eradicate the decay heat by establishing single and two-phase natural circulation (NC) flows of ∼4.5 % and ∼5.6 % of rated conditions in primary and secondary transport loops, respectively. The maximum PHRS capability is predicted to be ∼72 MWth which is more than 3 % of full power. The transients of flow, pressure, energy transfer and heat sink thermal conditions are analyzed when the system changes from forced to NC. Further, the influence of system conditions such as loop diameter, loop height, sink volume, sink temperature and heat exchanger area on PHRS performance was predicted and the changes in system parameters were analyzed. The vital parameters influencing the PHRS performance are identified based on sensitivity analyses. This investigation provides significant insight into the flow and heat transfer characteristics of two-phase and coupled NCLs in the PHRS.

Pricing Decisions in Dual-Channel Supply Chains Considering the Offline Channel Preference and Service Level

With the rapid development of e-commerce, the online channels encroaching on the offline sales market are becoming more serious, which will definitely harm the offline market. Moreover, there exists a certain percentage of consumers (mostly elderly people) who are not able to purchase online because they lack digital skills. Therefore, understanding the impact of the purchase channel preference and service level on pricing decisions is vital for the dual-channel supply chain management. Focusing on the channel preference and service level, we first develop an optimal pricing model containing centralized and decentralized decision-making for an online and offline retailer by deploying the Stackelberg game. We first develop a Stackleberg game to capture such a dual-channel supply chain with the offline channel preference and service level. Secondly, under centralized decision-making, we derive the optimal retail prices and obtain the optimal total profit. Thirdly, under decentralized decision-making, we obtain the optimal retail prices and optimal total profit as well. Moreover, extensive monotonicity properties when system parameters change are obtained. Relying on the theoretical results, firstly, we show that the improvement of the offline service level would lead to higher pricing of the commodities for both online and offline channels. From our numerical results, when the service level is improved, the offline and online optimal pricing increases by 47.5% and 31.1%, respectively, which may contradict the conventional belief that the improvement of one channel would harm another one. Secondly, we demonstrate that the benefit of improving the offline service level has a diminishing marginal effect. The numerical results show that when the current service level is low, the effectives of improving the service level is roughly five times that when the service level is high. This indicates that the investment in improving the offline service level should not be unlimited. Thirdly, we show that the pricing decision under centralized decision-making should be adopted with the existence of both the offline channel preference and offline service.

A fuzzy-PID controller for load frequency control of a two-area power system using a hybrid algorithm

This paper presents the use of a new hybrid optimization approach known as particle swarm optimization and grey wolf optimizer (PSO-GWO) for improving frequency stability load frequency control (LFC) in tow-area power systems. The approach consists in optimizing the fuzzy proportional-integral-derivative (fuzzy-PID) controller parameters with meta-heuristic hybrid algorithm: PSO-GWO. This technique allows to have dynamic responses with the least possible frequency deviation in very short response times. The approach proposes to controls the tie-line power and the frequency deviation in the considered two-area power systems under variable perturbation in load and changing of system parameters in order to evaluate its effectiveness. The suggested hybrid algorithm-based fuzzy-PID controller is compared with various widely used control methods in the literature such as PID controller and algorithms such as PSO and GWO in order to evaluate its effectiveness and its robustness. Through the simulations carried out on MATLAB/Simulink, the proposed PSO-GWO fuzzy-PID and the objective function exhibit improved performance, achieving minimal objective values. The proposed technique proved to be quite powerful tool in the resolution of problems related to electrical power systems, particularly in load frequency control.

Inventory rationing, admission control, and production capacity allocation in a make‐to‐stock/make‐to‐order manufacturing system

AbstractThis paper considers a manufacturing system in which products are produced in both make‐to‐stock (MTS) and make‐to‐order (MTO) modes. Production of MTS and MTO products is done in batches, incurs a setup cost, and is non‐preemptive. The inventory of MTS products fulfills the demand of multiple classes, and each class demand can be satisfied or rejected. Customer orders for MTO production can be accepted or rejected, and their size is the same as the production batch. The primary goal of this paper is to study a policy that coordinates inventory rationing, admission control, and production capacity allocation to maximize the system's profit. We formulate the problem as a Markov decision process model and identify the structure of optimal control policies. We investigate the effect of inventory rationing on the profit by comparing its performance to that of the system with a first‐come‐ first‐serve policy to allocate inventory to multiple demand classes and study the extent to which the benefit of inventory rationing can be affected by system parameter changes. We also propose a heuristic that manages control decisions from linear threshold functions. Our test results from numerical examples show that the average percentage difference between the optimal and heuristic policies is within 1.2%.

Nonparametric statistical analysis of system resilience migration and application for electric distribution structures

This paper proposes a set of nonparametric statistical tools for analyzing the system resilience of civil structures and infrastructure and its migration upon changes in critical system parameters. The work is founded on the classic theoretic framework that system resilience is defined in multiple dimensions for a constructed system. Consequentially, system resilience can lose its parametric form as a random variable, falling into the realm of nonparametric statistics. With this nonparametric shift, traditional distribution-based statistics are ineffective in characterizing the migration of system resilience due to the variation of system parameters. Three statistical tools are proposed under the nonparametric statistical resilience analysis (npSRA) framework, including nonparametric copula-based sensitivity analysis, two-sample resilience test analysis, and a novel tool for resilience attenuation analysis. To demonstrate the use of this framework, we focus on electric distribution systems, commonly found in many urban, suburban, and rural areas and vulnerable to tropical storms. A novel procedure for considering resourcefulness parameters in the socioeconomic space is proposed. Numerical results reveal the complex statistical relations between the distributions of system resilience, physical aging, and socioeconomic parameters for the power distribution system. The proposed resilience distance computing and resilience attenuation analysis further suggests two proper nonparametric distance metrics, the Earth Moving Distance (EMD) metric and the Cramévon Mises (CVM) metric, for characterizing the migration of system resilience for electric distribution systems.

Modeling the dynamic interaction between machine tools and their foundations

The performance of a machine tool is directly influenced by the characteristics of the floor, subsoil, and their interaction with the installed machine. Installing a machine tool in its operational environment poses a distinct challenge that bridges mechanical and civil engineering disciplines. This interdisciplinary issue is often overlooked within the individual separate disciplines. However, effectively addressing this challenge requires a comprehensive understanding of mechanical and civil engineering principles. To address this problem, the present study proposes a method for improved modeling of the dynamic properties of the machine tool by considering the foundation and the subsoil on which it is installed. The method is based on finite element modeling. Linear models of the system components and the connections between them were used. These, supplemented with damping expressed by complex stiffness, made it possible to determine the natural frequencies, mode shapes, and frequency response functions (based on which the transmissibilities were obtained). Based on the experimentally verified models of vertical and horizontal lathes, the sensitivity analysis aimed at estimating the impact of changes in system parameters on vibration transmissibility for a floor-type and a block-type foundation was conducted. Thus, it was possible to identify those machine tool-support-foundation-subsoil system parameters that had the most significant impacts on the vibration's transmissibility. After analyzing the cases discussed, it became evident that the transmissibility of vibrations is primarily influenced by two key factors. First and foremost, the properties of the structural loop of the machine tool played a significant role. Additionally, the characteristics of the subsoil on which the foundation was situated emerged as a crucial determinant in the observed vibration transmissibility.

Load frequency control in power systems with high renewable energy penetration: A strategy employing P[formula omitted](1+PDF) controller, hybrid energy storage, and IPFC-FACTS

The high penetration of Renewable Energy Sources (RESs) in the modern power system poses a challenge to power system stability. This stability is affected by the stochastic, fluctuating output of RESs, which is influenced by weather conditions, and a lack of inertia resulting from reduced rotating mass. To address this issue, a new controller, referred to as Proportional-Fractional Integrator Plus Proportional-Derivative with Filter, PIλ(1+PDF), is designed for Load Frequency Control (LFC) with the support of a Hybrid Energy Storage System (HESS) for power systems with high-RES penetration. The HESS comprises a Superconducting Magnetic Energy Storage System (SMES) and a Vanadium Redox Flow Battery (VRFB) coupled with an Interline Power Flow Controller Flexible AC Transmission Systems (IPFC-FACTs) controller. The HESS, working in conjunction with the proposed LFC, injects virtual inertia and maintains power flow to expedite the frequency stability process. These systems are also integrated with Alternating Current (AC) and High Voltage Direct Current (HVDC) transmission lines to collectively enhance both the system's stability and the capacity of its transmission lines. To optimize the PIλ(1+PDF) controller parameters, Zebra Optimization Algorithm (ZOA) is employed utilizing an Integral Time Absolute Error (ITAE) objective function. The proposed controller is tested on a four-area power system integrated with a wind turbine, photovoltaic (PV) panels, a biodiesel generator, and a hydrogen aqua electrolyzer fuel cell, representing a high penetration of RESs in modern power systems. The results are compared with those obtained using Proportional-Integral-Derivative (PID) and Fractional Order Proportional Integral Derivative (FOPID) controllers. Sensitivity analysis and robustness tests are also performed to verify the stability of the power network by changing system parameters and under randomly chosen loading conditions. The proposed PIλ(1+PDF) controller tuned with ZOA outperforms PID and FOPID controllers by minimizing settling time for frequency changes by 62 %, eliminating overshoot, and reducing undershoots for frequency and tie-line power changes by 73 % and 55 %, respectively. Simulation results demonstrate that the proposed controller outperforms PID and FOPID controllers by effectively damping frequency and tie-line deviations, resulting in reduced frequency overshoots, undershoots, and shorter settling times.

Detection of Demagnetization Faults in Electric Motors by Analyzing Inverter Based Current Data Using Machine Learning Techniques

Demagnetization of the rotor magnets is a significant failure mode that can occur in permanent magnet synchronous machines (PMSMs). Early detection of demagnetization faults can help change system parameters to reduce power output or ensure safety. In this paper, the effects of demagnetization faults were analyzed both in simulation and experiments using the example of drone motors. An approach was investigated to detect even minor demagnetization faults that does not require any additional sensing effort. Machine learning (ML) techniques are used to analyze the phase current data directly received from the inverter to enable anomaly detection. For this purpose, the phase current is transformed by the Fast Fourier Transform (FFT), the spectral data is then reduced in dimensionality, followed by an anomaly detection algorithm using a one-class support vector machine (OC-SVM). To ensure simplified initialization of the ML model without the need for training sets of damaged drives, only data from magnetically undamaged motors was used to train the models for anomaly detection. Different selections of considered harmonics and different metrics were investigated using the experimental data, achieving a precision of up to 99%, a specificity of up to 98%, and an accuracy of up to 90%.

Performance evaluation of the SMART passive safety injection system against the SBLOCA scenario with the SMART-ITL facility

A set of system performance tests has been performed and the thermal-hydraulic behaviors were investigated for the passive safety injection system (PSIS) of the SMART design. Major thermal-hydraulic characteristics of core cooling in reactor coolant system and safety injection (SI) in PSIS were investigated using the SMART-ITL. The parametric effects of break size, break location and train number on the PSIS performance were discussed with the relevant SMART-ITL data. Compared with the 2.0 inch SI line break test, the 0.4 inch SI line break test has a milder change of system parameters. The pressure is reduced more quickly, the decrease of water level is slower and the break mass flow rate is higher during the pressurizer safety valve line break than during the SI line break. Major thermal-hydraulic parameters were compared among single, two and full train operation of the PSIS focusing on the effect of train number. It was shown that multiple trains of CMT and SIT were operated independently and the reactor vessel (RV) inventory increased proportionally with the addition of each train. Sufficient SI water was injected into the RV in a passive manner to cool down the reactor core efficiently during the full train test.