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Records with Subject: Process Control
Showing records 101 to 125 of 3434. [First] Page: 1 2 3 4 5 6 7 8 9 Last
Active Thermal Management of Electric Motors and Generators Using Thermoelectric (Peltier Effect) Technology
Stephen Lucas, Romeo Marian, Michael Lucas, Titilayo Ogunwa, Javaan Chahl
May 23, 2023 (v1)
Keywords: core cooling, core heating, core temperature control, electrical insulation, thermoelectric cooler
Electric motors and generators underpin life in today’s world. They are numerous and widespread and consume approximately 45% of the world’s energy. Any improvements in efficiency or reductions in their whole-of-life costs are actively and continually being sought. While designs accommodate the removal of heat caused by internal losses because of inefficiencies, temperature variations due to load changes and environmental temperature fluctuations, and system harmonic content still stresses electrical insulation systems. This causes the fretting of insulation, combined with moisture ingress, which leads to leakage currents and, consequently, the early failure of the electrical insulation. This paper explores the addition of thermoelectric coolers/heaters (TECs) or Peltier effect devices. We show that these solid-state devices can actively support the thermal management of a motor by keeping its internals hot, reducing moisture ingress when off, and assisting in heat removal when under l... [more]
Online Adaptive Parameter Estimation of a Finite Control Set Model Predictive Controlled Hybrid Active Power Filter
Silvia Costa Ferreira, João Gabriel Luppi Foster, Robson Bauwelz Gonzatti, Rondineli Rodrigues Pereira, Guilherme Gonçalves Pinheiro, Bruno P. Braga Guimarães
May 23, 2023 (v1)
Keywords: dynamic reactive power compensation, finite control set model predictive control, hybrid active power filter, LCL-filter, Model Predictive Control, parameter estimation
This paper presents a novel strategy for online parameter estimation in a hybrid active power filter (HAPF). This HAPF makes use of existing capacitor banks which it combines with an active power filter (APF) in order to dynamically compensate reactive power. The equipment is controlled with finite control set model predictive control (FCS-MPC) due to its already well-known fast dynamic response. The HAPF model is similar to a grid-connected LCL-filtered converter, so the direct control of the HAPF current can cause resonances and instabilities. To solve this, indirect control, using the capacitor voltage and the inverter-side current, is applied in the cost function, which creates high dependency between the system parameters and the equipment capability to compensate the load reactive power. This dependency is evaluated by simulations, in which the capacitor bank reactance is shown to be the most sensitive parameter, and, thus, responsible for inaccuracies in the FCS-MPC references.... [more]
An Improved Q-Axis Current Control to Mitigate the Low-Frequency Oscillation in a Single-Phase Grid-Connected Converter System
Kai Wei, Changjun Zhao, Yi Zhou
May 23, 2023 (v1)
Keywords: electric railway system, low-frequency oscillation, small-signal impedance model
An electric railway system is a typical single-phase grid-connected converter system, and the low-frequency oscillation (LFO) phenomenon in electric railway systems has been widely reported around the world. Previous research has indicated that the LFO is a small-signal instability issue caused by impedance mismatching between the traction network system and electric trains. Therefore, this paper proposes an improved q-axis current control method to reshape the train’s impedance. The proposed method can be implemented easily by relating a reverse q-axis reactive current directly to the reference of the q-axis current under the dq current decoupled control. Moreover, considering the additional q-axis reactive current control, a small-signal impedance model of a train−network system is built. The impedance-based analysis results indicate that the proposed q-axis reactive current feedback control can increase the magnitude of the train’s impedance, which is beneficial to enhancing the sys... [more]
Research on a Modeling and Control Strategy for Interleaved Boost Converters with Coupled Inductors
Zhuangzhi Dai, Jilong Liu, Kefeng Li, Zhiqin Mai, Guijing Xue
May 23, 2023 (v1)
Keywords: controller design, coupled inductors, DC–DC converters, interleaved boost, small-signal model
Interleaved DC−DC converters have significant advantages in improving the capability of power converters, and coupling the filtering inductor of the converter could further increase the power density. However, existing modeling and controller designs are complex and require multiple sensors to be involved in the control, which is not conducive to engineering implementation and reducing production costs. In view of this problem, taking a two-phase interleaved boost converter with a coupled inductor as an example, the small-signal models of the converter are derived for the resistive load and constant voltage source load using the state averaging method. The total inductor current is engaged in the control as a feedback signal, avoiding the coupling effect of the inductor on increasing the complexity of the controller. Based on this, a double closed-loop controller is designed, and a prototype of the two-phase interleaved boost converter with coupled inductor is built. Only one current s... [more]
Secondary Frequency Regulation Control Strategy with Electric Vehicles Considering User Travel Uncertainty
Xiaohong Dong, Yang Ma, Xiaodan Yu, Xiangyu Wei, Yanqi Ren, Xin Zhang
May 23, 2023 (v1)
Keywords: controllable capacity, electric vehicle, EV orderly charging, secondary frequency regulation, vehicle to grid
The premise of electric vehicles (EVs) participating in the frequency regulation (FR) of power systems is to satisfy the charging demands of users. In view of problems such as the uncertainty of EV users’ departure time and the increase in power supply pressure due to disordered charging in the frequency regulation process of EV clusters, a secondary frequency regulation control strategy with EVs considering user travel uncertainty is proposed. Firstly, EV charging history was analyzed, a reliability parameter was introduced to describe the user travel uncertainty, and an individual EV controllable domain model based on reliability correction was constructed. Then, EV clusters were grouped according to charging urgency and state of charge (SOC), and the controllable capacity of EV clusters was determined. Finally, EV frequency regulation capability parameters and charging urgency parameters were defined to determine the EV frequency regulation priority list, combined with the EV state... [more]
Small Signal Modeling of LLC Converter with LED Load and Quasi-Resonant Controller Based Active Ripple Rejection
Xiao Long, Dongdong Chen
May 23, 2023 (v1)
Keywords: active ripple rejection, LLC converter, quasi-resonant controller, small signal modeling, SPLL
This paper has analyzed the defects of the traditional extended description function (EDF) based LLC small signal modeling method when driving light emitting diode (LED) load and proposed an accuracy improvement method. Detailed small signal model modeling methods have been deduced, and the accuracy of different modeling methods has been compared thoroughly. To suppress the second-order harmonic ripple in the direct current link-induced output current ripple, a quasi-resonant controller (QRC) is adopted to realize active ripple rejection (ARR). Considering the frequency of the second-order harmonic ripple changes with the grid voltage frequency, a single-phase software phase lock loop (SPLL) is adopted to extract the frequency of the second-order harmonic. By dynamically regulating the control parameter of the QRC according to the locked second-order frequency, output voltage ripple active rejection ability immune to grid voltage frequency deviation is obtained. Based on the deduced ac... [more]
Condition-Based Maintenance of Gensets in District Heating Using Unsupervised Normal Behavior Models Applied on SCADA Data
Valerio Francesco Barnabei, Fabrizio Bonacina, Alessandro Corsini, Francesco Aldo Tucci, Roberto Santilli
May 23, 2023 (v1)
Keywords: condition based maintenance, early fault detection, multi-MW gensets SCADA data, multivariate time series
Increasing interest in natural gas-fired gensets is motivated by District Heating (DH) network applications, especially in urban areas. Even if they represent customary solutions, when used in DH, duty regimes are driven by network thermal energy demands resulting in discontinuous operation, which affects their remaining useful life. As such, the attention on effective condition-based maintenance has gained momentum. In this paper, a novel unsupervised anomaly detection framework is proposed for gensets in DH networks based on Supervisory Control And Data Acquisition (SCADA) data. The framework relies on multivariate Machine-Learning (ML) regression models trained with a Leave-One-Out Cross-Validation method. Model residuals generated during the testing phase are then post-processed with a sliding threshold approach based on a rolling average. This methodology is tested against nine major failures that occurred on the gas genset installed in the Aosta DH plant in Italy. The results sho... [more]
Analysis of the Efficiency of Traction Drive Control Systems of Electric Locomotives with Asynchronous Traction Motors
Sergey Goolak, Borys Liubarskyi, Ievgen Riabov, Vaidas Lukoševičius, Artūras Keršys, Sigitas Kilikevičius
May 23, 2023 (v1)
Keywords: asynchronous electric motor, direct torque control, electric traction drive, vector control
An analysis of the operating conditions of the traction drives of an electric rolling stock with asynchronous traction motors was conducted. In the process of operation, the electric traction drive with both direct torque control and vector control was found to possibly experience unstable modes, both in terms of power supply and load. The models of electric locomotive traction drives with asynchronous electric motors with either vector or direct torque control were adapted to account for the possible presence of the aforementioned operational factors. As a result of the modeling, the starting characteristics of the electric traction drives with different control systems were obtained both in the absence and in the presence of power supply and load disturbances. The following cases were investigated for the drive with vector and direct torque control in the absence of power supply and torque disturbances: drive output at the rated speed of rotation of the electric motor shaft; 10% redu... [more]
Comparative Analysis of Wind Farm Simulators for Wind Farm Control
Minjeong Kim, Hyeyeong Lim, Sungsu Park
May 23, 2023 (v1)
Keywords: power optimization, wake model, wind farm control, wind farm simulator
This paper conducts a comparative analysis of three wind farm simulators, examining the influence of wake on the local wind speed and power output for downstream turbines using experimental data. The study features experiments in three distinct scenarios, evaluating differences among the simulators by calculating the local wind speed and power for each. Each simulator employs a unique wake model, which substantially affects the local wind speed experienced by downstream turbines. Furthermore, the experiment involves adjusting parameter values for each simulator to assess their respective impacts on wind farm performance. The findings of this research are expected to play an important role in investigations related to power optimization and wake effects in the wind farm control.
Supervisory Control and Data Acquisition for Fault Diagnosis of Wind Turbines via Deep Transfer Learning
Silvio Simani, Saverio Farsoni, Paolo Castaldi
May 23, 2023 (v1)
Keywords: condition monitoring, convolutional neural networks, diagnostics, Fault Detection, supervisory control and data acquisition, transfer learning, wind turbines
The installed wind power capacity is growing worldwide. Remote condition monitoring of wind turbines is employed to achieve higher up-times and lower maintenance costs. Machine learning approaches can be used for detecting developing faults in wind turbines in their earlier occurrence. However, training fault detection models may require large amounts of past and present data. These data are often not available or not representative of the current operation behaviour. These data can be acquired with supervisory control and data acquisition systems. Note also that newly commissioned wind farms lack data from previous operation, whilst older installations may also lack representative working condition data as a result of control software updates or component replacements. After such events, a turbine’s operation behaviour can change significantly so its data are no longer representative of its current behaviour. Therefore, this paper shows that cross−turbine transfer learning can improve... [more]
Effects of Astronomical Cycles on Laminated Shales of the Paleogene Shahejie Formation in the Dongying Sag, Bohai Bay Basin, China
Qiqi Li, Shang Xu, Junliang Li, Ruichao Guo, Guangwei Wang, Yufan Wang
May 23, 2023 (v1)
Keywords: astronomical forcing, Bohai Bay Basin, laminated shale, organic-rich shale, shale oil
Laminated shales are widely developed in the Dongying Sag and have attracted much attention as an oil reservoir. Macroscopically, these shales generally have multi-scale cyclicity, which is closely related to the development of laminae. Therefore, analyzing the origin of their cyclicity is helpful to understanding the formation mechanism of laminated shales and the vertical heterogeneity of shale reservoirs, which are of great significance for continental shale oil exploration and development. In this study, a gamma ray (GR) logging series, high-resolution elemental geochemical data, high-resolution core scanning photos and grayscale data, and mineralogical data were used to characterize the cyclicity of shale at different scales, and their relationship with different astronomical cycles was discussed. The results show that the Es3L and Es4U shale in the Dongying Sag has cyclicity from the meter-scale to the ten-meter scale and then to the hundred-meter scale, which is mainly manifeste... [more]
Exponential Curve-Based Control Strategy for Auxiliary Equipment Power Supply Systems in Railways
Shoeb Azam Farooqui, Chang-Hua Lin, Shiue-Der Lu, Hwa-Dong Liu, Adil Sarwar, Liang-Yin Huang
April 28, 2023 (v1)
Keywords: auxiliary equipment power supply system, exponential curve-based control strategy, isolated three-phase inverter, rail vehicles
An exponential curve-based (ECB) control strategy has been proposed in this paper. The proposed ECB control strategy is based on the growth and decay of charge in the series RC circuit and the harmonic elimination by detecting the Fourier expansion series of the auxiliary equipment power supply system’s (AEPSS) three-phase output voltage level. It can quickly adjust each duty cycle to the best value for driving the isolated three-phase inverter (ITPI) and produce a three-phase 380 VAC/60 Hz output. A comparison of the AEPSS output performance using the traditional voltage cancellation method (VCM) and the proposed ECB control strategy was performed. The hardware implementation of the system was performed on the prototype developed in the laboratory. These control strategies are tested under three conditions, i.e., (i) Vi = 550 VDC. (ii) Vi = 750 VDC. (iii) Vi = 800 VDC. The total harmonic distortion (THD) is 13.7%, 14.5%, and 14.9%, and the output voltage Vo is 372.3 VAC, 377.3 VAC, an... [more]
Advancing Manganese Content Prediction in Submerged Arc Welded Metal: Development of a Multi-Zone Model via the Calphad Technique
Jin Zhang, Ping Liu, Dan Zhang
April 28, 2023 (v1)
Keywords: chemical reactions, compositional control, equilibrium principles, gas–slag–metal equilibrium, submerged arc welding, welding process
Manganese is a vital element in determining the mechanical properties of submerged arc welded metal. To ensure a reliable weld, the equilibrium model has been used for decades to predict and control the manganese content, particularly when MnO-bearing fluxes are applied. However, the equilibrium model only considers chemical interactions within the weld pool zone, leading to significant inaccuracies. To address this limitation, we propose a multi-zone model that accounts for all of the essential reaction zones in the submerged arc process via the Calphad technique. The model’s accuracy is verified by predicting the manganese content, the flux oxygen potential, and the neutral point location for the typical MnO-bearing fluxes covering acidic, neutral, and basic fluxes. The results indicate that the multi-zone model offers superior accuracy compared to the equilibrium model, which neglects significant oxygen improvement and alloy evaporation in the droplet zone. Further analysis of therm... [more]
Predictive Control Strategy for Continuous Production Systems: A Comparative Study with Classical Control Approaches Using Simulation-Based Analysis
Amelia Chindrus, Dana Copot, Constantin-Florin Caruntu
April 28, 2023 (v1)
Keywords: continuous manufacturing, cyber-physical system, linear quadratic regulator, Model Predictive Control, proportional-integral-derivative controller
Due to today’s technological development and information progress, an increasing number of physical systems have become interconnected and linked together through communication networks, thus resulting in Cyber-Physical Systems (CPSs). Continuous manufacturing, which involves the manufacture of products without interruption, has become increasingly important in many industries, including the pharmaceutical and chemical industries. CPSs can be used to control and monitor the production process, which is essential in enabling continuous manufacturing. This paper is focused on the modeling and control of physical systems required in tablet production using dry granulation. Tablets are a type of oral dosage form that is commonly used in the pharmaceutical industry. They are solid, compressed forms of medication that are formulated to release the active ingredients in a manner that allows for optimal absorption and efficacy. Thus, a model predictive control (MPC) strategy is applied to a pl... [more]
Shewhart Control Charts Implementation for Quality and Production Management
Marcela Malindzakova, Katarína Čulková, Jarmila Trpčevská
April 28, 2023 (v1)
Keywords: Pearson test, production stabilization, quality marks, Shewhart control charts, variability control
Shewhart control charts are suitable for stable but repetitive production processes used for the subsequent identification of random deviations while indicating breached quality limits. They provide information on process variability and, at the same time, make it possible to obtain information on the reliability of monitored processes. The objective of this paper is to assess the quality characteristics of plastic mouldings for the needs of the automotive industry with the application of the control charts method, specifically Shewhart control charts. The Shewhart control charts were applied to evaluate the quality characteristics, or, more specifically, to evaluate the measured width and length of the produced plastic mouldings by statistical analysis. Statistical analyses show that the set parameters are not met in the first two days of the test series. An improvement in the process is observed on the last day of the test series. The process is well set, as confirmed by our verifica... [more]
Circuit Breaker Fault Diagnosis Method Based on Coil Current Time Sequence Phase Trajectory Characteristics
Yaqi Chen, Qiong Li, Yang Zou, Guohua Long, Nianping Yan, Ruixiang Fan
April 28, 2023 (v1)
Keywords: breaking coil current signal, circuit breaker, first-order forward differencing, phase space reconstruction, phase trajectory
The traditional circuit breaker fault diagnosis method suffers from insufficient feature information extraction and is easily affected by abnormal signal acquisition. To address this, this paper introduces the phase space reconstruction algorithm to reconstruct the current signal for fault diagnosis based on phase trajectory features. The proposed method uses a first-order forward differencing method and mutual information method to process abnormal data and select the parameters of the reconstruction, then extract overall and local inflection point features to construct a fault feature set. The support vector machine algorithm-based model is trained and tested using actual samples, and the results show that the proposed method can adaptively sample anomalous signals, exhibit strong robustness, and significantly improve the accuracy of fault classification.
Modified Whale Algorithm-Based Optimization for Fractional Order Concurrent Diminution of Torque Ripple in Switch Reluctance Motor for EV Applications
Nutan Saha, Prakash Chandra Mishra
April 28, 2023 (v1)
Keywords: cosine adapted modified whale algorithm optimized fractional order proportional integral (MWAO FO-PI) control, speed tracking, switched reluctance motor (SRM), torque ripple
This work proposes a new multi-objective optimization technique for concurrent diminution of torque ripple with the regulation of the speed of a 75 Kilowatt, 8/6, 4-phase SRM based on a double close loop, modified whale algorithm optimized fractional order proportional integral (MWAO FO-PI) control with a commutation angle controller. The system is analyzed and designed in MATLAB/SIMULINK environment. First, the performance of MWAO is tested on 30-dimensional standard benchmark functions. It is found that MWAO performance is better when examined on 30-dimensional standard benchmark functions, compared with WOA, and another six recently proposed state-of-art functions. Then, a double loop control based on the MWAO FO-PI controller is designed and implemented for concurrent diminution of torque ripple with the regulation of the speed of a 75 Kilowatt, 8/6, 4-phase SRM with a commutation angle controller. It was found that the percentage improvement achieved in the combined objective opti... [more]
Investigation on the Aerodynamic Performance of High-Pressure Cylinders under the Mode of Regulating Steam Supply with an Intermedium-Pressure Adjustment Valve
Pan Zhang, Xiwei Ke, Weiliang Wang, Qinghong Tang, Xiong Liu, Junfu Lyu, Xueyu Tang
April 28, 2023 (v1)
Keywords: control strategy, deep peak regulation, flow separation, isentropic efficiency
In order to investigate the operational performance of the high-pressure (HP) cylinder towards a 300 MW boiler unit, the three-dimensional calculation method was applied to simulate the aerodynamic flow characteristics of the last five stage cylinder blades, including limiting streamline, isentropic efficiency along the blade height, and relative work amounts. Simulation results show that with the back pressure controlled at 3.4 MPa and the inlet steam flow decreasing to a certain extent, the flow state of the last three stage blades begins to deteriorate. When the back pressure continues to drop, the flow state becomes unstable at the blade root and the blade tip on the suction surface of the rotor blade, while the flow state is stable on the pressure surface of the rotor blade and the surface of the stationary blade. If the flow rate decreases, the flow separation area on the suction surface of the moving blade decreases, and the flow performance can be improved. With the decrease in... [more]
Speed Control of Wheeled Mobile Robot by Nature-Inspired Social Spider Algorithm-Based PID Controller
Huma Khan, Shahida Khatoon, Prerna Gaur, Mohamed Abbas, Chanduveetil Ahamed Saleel, Sher Afghan Khan
April 28, 2023 (v1)
Keywords: Cuckoo Search Optimization (CSO), DC motor, kinematic modeling, Matlab, PID controller, Social Spider Optimization (SSO)
Mobile robot is an automatic vehicle with wheels that can be moved automatically from one place to another. A motor is built in its wheels for mobility purposes, which is controlled using a controller. DC motor speed is controlled by the proportional integral derivative (PID) controller. Kinematic modeling is used in our work to understand the mechanical behavior of robots for designing the appropriate mobile robots. Right and left wheel velocity and direction are calculated by using the kinematic modeling, and the kinematic modeling is given to the PID controller to gain the output. Motor speed is controlled by the PID low-level controller for the robot mobility; the speed controlling is done using the constant values Kd, Kp, and Ki which depend on the past, future, and present errors. For better control performance, the integral gain, differential gain, and proportional gain are adjusted by the PID controller. Robot speed may vary by changing the direction of the vehicle, so to avoid... [more]
Research on Fault Diagnosis Strategy of Air-Conditioning Systems Based on DPCA and Machine Learning
Yongxing Song, Qizheng Ma, Tonghe Zhang, Fengyu Li, Yueping Yu
April 28, 2023 (v1)
Keywords: air-conditioning system, fault diagnosis, Machine Learning, signal demodulation
The timely and effective fault diagnosis method is critical to the operation of the air-conditioning system and energy saving of buildings. In this study, a novel fault diagnosis method was proposed. It is combined with the signal demodulation method and machine learning method. The fault signals are demodulated by the demodulation method based on time-frequency analysis and principal component analysis (DPCA). The modulation characteristics of the principal component and DPCA sets with stronger features are obtained. Compared with time domain sets, the correct rate was increased by 16.38%. Then, as a machine learning method, the Visual Geometry Group—Principal Component Analysis (VGG-PCA) model is proposed in this study. The application potential of this model is discussed by using evaluation indexes of fault diagnosis performance and two typical faults of air conditioning systems. Compared with the other two convolution neural network models, the correct rate was increased by 17.1% a... [more]
Optimal Control of Rural Water Supply Network Based on Intelligent Algorithm
Bo Wang, Qi Yang, Ruiyang Sun, Zihan Chen, Xiangtian Nie
April 28, 2023 (v1)
Keywords: economy, LM algorithm, NSGA-II algorithm, reliability, water supply network
Optimizing Rural Water Supply Network (RWSN) is the basis for improving rural people’s lives and improving people’s health. Currently, the RWSN in China is relatively backward and can no longer meet the needs of the unified management of rural water resources. To optimize the RWSN, this study innovatively established a Multi-Objective Optimization Mathematical Model (MOMM) of RWSN, combining economic factors and reliability. This experiment first analyzes the characteristics of the RWSN system and then establishes a MOMM of a water supply network. NSGA-II algorithm and LM algorithm are introduced to handle the multi-objective model. The research results show that compared to Web decision tools, the RWSN based on the LM-NSGA-II algorithm can save 5.4% of the total annual cost of water supply pipelines. Therefore, the MOMM of the rural water supply pipeline based on the LM-NSGA-II algorithm has better economy and reliability. The experiment aims to provide certain reference values for th... [more]
Analysis of Regulating Valve Stem Fracture in a Petrochemical Plant
Fuping Guo, Yunrong Lyu, Zhihong Duan, Zhiqing Fan, Weiming Li, Falin Chen
April 28, 2023 (v1)
Keywords: failure analysis, fatigue fracture, fluid-structure interaction, regulating valve
This paper investigates the failure of a regulating valve stem in a petrochemical plant, which was mainly caused by vibration fatigue under small opening conditions. The fractured valve stem was analyzed using macroscopic analysis, chemical composition analysis, mechanical property analysis, metallographic analysis, fracture surface observation, and energy spectrum analysis. Additionally, fluid-structure interaction (FSI) modal analysis was used to investigate the failure of the regulating valve. The results indicate that the valve opening had a direct impact on the vibration of the valve body, which, when operated at small openings, led to fatigue fracture at the step of variable cross-section. The paper suggests a smooth transition treatment be performed at the variable cross-section of the valve stem to avoid stress concentration. Although this study is limited to a specific case, it provides valuable insights for the failure analysis of valves operating at small openings.
Frequent Alarm Pattern Mining of Industrial Alarm Flood Sequences by an Improved PrefixSpan Algorithm
Songbai Yang, Tianxing Zhang, Yingchun Zhai, Kaifa Wang, Guoxi Zhao, Yuanfei Tu, Li Cheng
April 28, 2023 (v1)
Keywords: alarm flood, alarm management, industrial alarm systems, PrefixSpan algorithm, sequential pattern recognition
Alarm systems are essential to the process safety and efficiency of complex industrial facilities. However, with the increasing size of plants and the growing complexity of industrial processes, alarm flooding is becoming a serious problem and posing challenges to alarm systems. Extracting alarm patterns from an alarm flood database can assist with an alarm root cause analysis, decision support, and the configuration of an alarm suppression model. However, due to the large size of the alarm database and the problem of sequence ambiguity in the alarm sequence, existing algorithms suffer from excessive computational overhead, incomplete alarm patterns, and redundant outputs. In order to solve these problems, we propose an alarm pattern extraction method based on the improved PrefixSpan algorithm. Firstly, a priority-based pre-matching strategy is proposed to cluster similar sequences in advance. Secondly, we improved PrefixSpan by considering timestamps to tolerate short-term order ambig... [more]
Predicting Final PCDD/F Emissions by Coupling Adsorption Model of Activated Carbon and Relationships of PCDD/Fs and Flue Gas Compositions
Jianjun Cai, Lingxia Zhu, Da Huang, Ming Luo, Xingying Tang, Wangqi Liu
April 28, 2023 (v1)
Keywords: municipal solid waste incinerators, online monitoring, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), predicting model, real-time control
Due to their low concentration and complex nature, the low-cost online and real-time monitoring of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) is a challenge. In this paper, based on a coupling adsorption model of activated carbon and the relationship of PCDD/Fs and flue gas, an online monitoring system with real-time control of final PCDD/F emissions was built for the tracing and control of PCDD/F emissions in municipal solid waste incinerators (MSWIs). According to the online monitoring system, the effects of activated carbon concentration, the specific surface area of activated carbon (AC), operating temperature, contact time, fly ash concentration, residence carbon concentration of fly ash, and the lime concentration of final PCDD/F emissions were discussed. These MSWI operating parameters for reaching standards of 0.1 ng international toxic equivalents (TEQ)/Nm3 and 0.05 ng TEQ/Nm3 were summarized by the predicting model based on several published... [more]
Research on Adaptive Distribution Control Strategy of Braking Force for Pure Electric Vehicles
Jingang Liu, Lei Bu, Bing Fu, Jianyun Zheng, Gaosheng Wang, Lihong He, Yuliang Hu
April 28, 2023 (v1)
Keywords: adaptive distribution control, braking force, electric vehicles, regenerative braking, synchronous adhesion coefficient
The actual driving conditions of electric vehicles (EVs) are complex and changeable. Limited by road adhesion conditions, it is necessary to give priority to ensuring safety, taking into account the energy recovery ratio of the vehicle during braking to obtain better braking quality. In this work, an electric vehicle with an EHB (electro-hydraulic braking) system whose braking force adaptive distribution control strategy is studied. Firstly, the vehicle dynamics model, including seven degrees of freedom, tire, drive motor, main reducer, battery pack, and braking system, was constructed, which is attributed to the vehicle configuration and braking system scheme. Second, based on curve I and ECE regulations, the adaptive braking force distribution control strategy was formulated by taking the maximum regenerative braking torque as the inflection point, the synchronous adhesion coefficient as the desired point, and the battery SOC, road adhesion coefficient, and braking strength as the th... [more]
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