Operation Control Method Research Articles

Theoretical background of experimental methods for studying the influence of technical conditions of shock absorbers on lateral tire reactions

The article studies the technical condition of shock absorbers which influences the occurrence of lateral reactions when the vehicle is passing through a single irregularity under the influence of lateral forces. The lateral reactions determine the properties of the directional and trajectory stability of the car. These properties allow us to consider lateral reactions as diagnostic parameters for the method of operational control of the technical condition of the suspension according to the stability criteria of the car. A mathematical model developed by the authors was applied. The model is based on the dynamics equations of the sprung and non-sprung masses, taking into account the technical condition of the shock absorbers. To describe the longitudinal and lateral reactions, the normalized slip function is used. The process of car movement around a circle was simulated with various parameters of the technical condition of the shock absorbers. Simulation results were processed using approximation and correlation analysis methods. The dependences of changes in the maximum value of lateral reactions on each wheel depending on the technical condition of shock absorbers were obtained. The presence of a strong correlation between the magnitude of the lateral reaction and the technical condition of its own shock absorber is established. Changing the technical condition of improper shock absorbers to a lesser extent affects the lateral reaction, but at the same time reduces the quality of diagnosis. Foundations of the method for conducting a road experiment were developed.

Cистеми контролю та діагностики в інтегрованих АСУ товстолистовими станами.

Diagnosing the equipment of complex technological installations is a guarantee of their safe and efficient performance. The aims of the diagnostic systems creation are the following: timely prevention of possible failures and malfunctions of systems and equipment; the necessi-ty of having a complete and holistic picture of the actual technical condition of the operating systems and equipment; high accuracy forecasting of the residual life of the equipment; minimization of cost and increase of efficiency of works on technical conditions monitoring, maintenance, repairs and management of resource characteristics of systems and equipment; continuous improvement, based on objective performance data, actual characteristics of safety, reliability and operational readiness. To such complex technological installations there belongs the equipment of hot rolling shops, for example, mechanical equipment of the mill, electric drive with control systems, devices and control systems for hydraulics, lubrication and cooling management, ventilation stations, pumping stations; switchgear cells (high voltage switches), complex of APCS of heavy-plate mills rolling technical means. The article considers some methods of operational control of the technical condition of the heavy-plate rolling mills equipment. The factors that influence the efficiency of the diagnostic algorithms used in the APCS, in particular, the organization of collection and processing of statistical data on the possibilities of malfunctions and the costs of their search and elimination are determined in the paper. Formalization of methods for construction and description of mathematical models of the object of diagnostics is performed. Utilization of the subsystem of control and diagnostics in the APCS of modern rolling mills provides a significant improvement in the reliability of the APCS of heavy-plate mills rolling, as well as some economic effects.

Operational Control Method for Managing Homogeneity of Multicomponent Mixtures Based on Optoleptic Photosensitive Scanning of their Surface during Mixing

To control and manage the degree of homogeneity of the mixture, an optoleptic method of photosensitive scanning of the mixture surface has been developed, which makes it possible to efficiently control and manage the homogenization of the mixture during its production. To improve the accuracy of the method in order to increase the contrast during photosensitive scanning of the surface, it is proposed to introduce a lumogen indicator into the mixture. An example of the application of the proposed method in the production of magnesial cement blends for the preparation of solutions for cementing casing strings of oil and gas wells is considered.

Operational control of energy consumptions of reclamation machines

The article presents the results of theoretical and experimental studies of the effectiveness of the application of a new method of operational control over the consumption of fuel and lubricants (POL) of construction and reclamation machines using GIS technologies. Operational control over the consumption of fuels and lubricants is necessary to place orders for their purchase on stock exchanges, to manage the route of refueling vehicles between construction sites and to assess the continuity of the machines at the construction site. Remote sensing of the work of the organization’s construction machines will allow you to quickly manage the processes of their transfer from facility to facility, as well as to monitor the timing of specific work (production assignment) by these machines, units and teams.

Hybrid LCC-AAC HVDC transmission system

A hybrid HVDC transmission system based on a line-commutated converter (LCC) and an alternate arm converter (AAC) is developed in this article. The basic operation principles and control methods of the proposed LCC-AAC hybrid HVDC system are demonstrated following with appropriate system design and parameter selection. In addition, this paper proposes a set of control schemes for riding through ac faults and handling dc fault. The operation and performance of both converters in such a hybrid HVDC configuration are verified through a detailed set of results based on a 3000 MVA LCC-AAC hybrid HVDC system including steady state operation, ac-grid harmonics & dc-side ripple analysis, reference tracking (active power change at LCC station, reactive power change at AAC station) and system performance under ac-grid faults without blocking converter at both terminals of the HVDC system. Also, the response of the hybrid system under dc fault presents potential dc fault handling capability compared with the hybrid system based on LCC and modular multilevel converter (MMC) with half-bridge submodules (HBSMs). The hybrid LCC-AAC HVDC transmission system lays preliminary steps for research on complex mixed converter multiterminal dc configurations in future dc super grids.

METHOD FOR CONTROLLING DATA PRESENTED IN THE DEDUCTION CLASS

The article proposes a method for increasing the reliability of control of data presented in the class of residues. The procedures for obtaining a positional attribute of a non-positional code and forming a one-time code that is the basis of the proposed method for controlling data in the deduction class are considered. A method for controlling data in the deduction class is given and described. An example of implementing the control method for a specific class of deductions is considered. Since the developed method of operational control of data in the class of deductions and devices for its implementation has a very low reliability of control, a method for increasing the reliability of control based on the wellknown method of operational control of information in the class of deductions is proposed.The results of calculations and comparative analysis of the reliability of control of data in class of residues showed that with an increase in the bit grid of processed data, the efficiency of non-positional coding in the class of residues increases significantly.

Maximum Torque Per Ampere Control of a Single-Phase Permanent Magnet Synchronous Motor, Part 2: Variable Speed Control Method

In this paper, the control method for the minimum copper-loss operation of single-phase permanent magnet synchronous motor (SP-PMSM) according to given loads is proposed. The proper inverter output voltage to minimize a copper-loss is calculated from a voltage and current limit. Also, the inverter output voltage can be calculated for all load torque variations under the maximum torque capability curve of the SP-PMSM in all speed range. The proposed control method is simple and easy to implement since it has no inner current controller. The performance of the proposed method is verified by experimental results.

Determination of the total content of aromatic hydrocarbons by Fourier-transform IR spectroscopy in the products of diesel hydrofining

A comparative analysis of current methods for determination of aromatic hydrocarbons in the components of diesel fuel revealed that IR spectrometry appeared to be the most optimal method for operational control of the content of aromatic hydrocarbons in medium distillate products of the hydrogenation process. We developed a procedure for quantitative determination of aromatic hydrocarbons in the components of diesel fuel using IR Fourier spectroscopy. The analysis of absorption spectra of the components of diesel fuel revealed that the optical density of the stretching vibration band of the aromatic ring is proportional to the quantitative content of aromatic hydrocarbons (AHC) in the components of diesel fuel. One of the components for compounding diesel fuels obtained at JSC «ANKhK» during hydrotreating of raw materials under severe conditions (30 MPa, 380 – 400°C) was selected as an object of the study. Conditions of IR spectrometric analysis (wave number — 1606.5 cm–1, cell material — NaCl, absorbing layer thickness — 0.1 cm) were specified after recording of the absorption spectrum of the purified component. To construct a calibration dependence the total AHC content and corresponding optical density of the sample were determined by the methods of HPLC and IR spectrometry, respectively. The samples of hydrogenate under study (taken at different timepoints) contained 1 – 8% AHC on average depending on the parameters of a continuously operating unit. The characteristics of the proposed procedure were evaluated in accordance with the requirements of RMG 76–2014. The correctness of the obtained results of AHC determination was confirmed in comparison with the data of independent (tetrimetric) analysis. The use of the developed method in analysis of other components of diesel fuel, requires additional studies to determine the interfering substances and assess their impact on the accuracy of AHC determination.

Bidirectional Operation Scheme of Grid-Tied Zeta Inverter for Energy Storage Systems

The zeta inverter has been used for single-phase grid-tied applications. For its use of energy storage systems, this paper proposes the bidirectional operation scheme of the grid-tied zeta inverter. A shoot-through switching state is introduced, providing reliable bidirectional operation modes. A shoot-through duty cycle is utilized for the bidirectional grid current control of the inverter. The grid current is bidirectionally controlled by the shoot-through duty cycle, which enables the inverter to operate with seamless change of operation modes. Over the state-of-the art techniques using flyback and Cuk inverter topologies, the grid-tied zeta inverter using the proposed operation scheme provides advantages of high efficiency, low cost, and high reliability. The operation principle is presented by describing the operation mode and control method for the grid-tied zeta inverter. A 500 W prototype has been built and tested to verify its operation principle.

ESTIMATION OF THE SUITABILITY OF METHODS FOR DETERMINING LACTIC ACID CONTENT IN DIFFUSION JUICE FOR APPLICATION IN CHEMICAL AND TECHNICAL CONTROL OF SUGAR PRODUCTION

Development of microbiological infection in the process of production of diffusion juice is one of the most important factors affecting the quality of diffusion juice and sucrose loss. In this regard, it is important to promptly monitor the microbiological contamination of mixture from water and beet chips in the diffusion apparatus. Lactic acid is used as an indicator of the degree of microbiological contamination of the diffusion juice. Traditionally, when calculating unaccounted sucrose losses on diffusion, the titrimetric method is used to determine the concentration of lactic acid with preliminary isolation of acid anions from the diffusion juice on ionite columns. However, this method is time-consuming and labor-intensive and is not suiTable for operational control. The article suggests using a simpler and less time-consuming spectrophotometric method for operational control, based on measuring the optical density of the colored product of the reaction of lactate ions with iron(III) chloride at a wavelength 400 nm. The results of evaluating the consistency of data on the content of lactic acid in diffusion juices obtained using the traditional and spectrophotometric methods are presented in article. The results of data analysis using the Bland-Altman descriptive statistics method confirm that the data obtained by various methods are in good agreement with each other, and therefore the spectrophotometric method for determining the concentration of lactate ions can be used in production control in the sugar industry.

Geophysical methods for controlling the useful component content as the basis for the quality management system at mining and processing enterprises

The article is devoted to substantiating the possibility of creating a common quality management system for iron ore plants based on geophysical methods of operational quality control for mineral raw materials. Due to the fall in prices on the world markets of iron ore raw materials, the financial and economic situation of the mining and processing enterprises in Ukraine has significantly worsened. Thus, the problem of effective control and quality management in mining has become of maximum importance. The availability of timely and reliable information about the content of the useful component will allow responding quickly, forming an integrated final ore cargo flow of the plant of exact quality required by the mining and concentration complex. The need to create a common quality management system is dictated by the fact that the iron ore has a heterogeneous distribution of the useful component content within the deposit, the extraction and transport equipment operates irregularly, resulting in ore cargo flows of various degrees of integration have significant amplitude and frequency oscillations, both by quality and quantity indicators. The instability of the useful component content in the ore cargo, which is aimed at enrichment, leads to a decrease in concentrate output, increase of losses in the tails, costs increase, decrease of the enterprise profit and decrease of its competitiveness. The mathematical model of ore cargo flow formation, which has a range of limitations on quality characteristics, is given. The structure and functional scheme of the quality management system of the mining and processing plant are substantiated. As a result of theoretical studies, the possibility of using radiometric and magnetometric methods for the operational quality control of the iron ore raw materials in the conditions of mining and processing plants by geophysical devices developed by the staff of the problem-branch laboratory of the Kryvyi Rih National University and Rudpromheofizyka LLC is substantiated. The basic technological characteristics of devices and systems are given, information on their introduction into production is provided. It is concluded that the researches carried out and the devices introduced on their basis have created objective prerequisites for substantiating the quality management system at mining and processing plants. The devices and operational control systems based on geophysical methods allow to cover all major stages of mining and processing, to receive timely and reliable information on the condition and dynamics of changes in the useful component content, to efficiently quality management at mining and processing plants, to increase the enterprises competitiveness and profitability.

A Hybrid Three-Phase AC/DC Power System for Low-Frequency Pulsed Load Applications

A hybrid three-phase ac/dc power system, which is composed of a diode-bridge rectifier and a two-stage ac–dc converter, is proposed in this article, for low-frequency pulsed load applications. With the proposed hybrid power system, the low-frequency pulsed load power is decoupled with the average power of the ac source, while the high-frequency harmonics induced by the diode-bridge rectifier is compensated by the ac–dc converter. Fault-tolerant operation is achieved with four possible operation modes of the proposed hybrid power system. Therefore, high reliability is achieved with these redundant operation modes. Operation principles, control methods, and design considerations of the hybrid ac/dc power system are analyzed in detail. An experimental prototype is built and tested to verify the effectiveness and feasibility of the proposed hybrid ac/dc circuit and its control strategy.

An Energy Storage System’s Operational Management and Control Method Considering a Battery System

Losses in energy storage systems (ESSs) result from losses in battery systems and power conversion systems (PCSs). Thus, the power difference between the input and output occurs as a loss, which is considered an operational cost. Additionally, since battery systems consist of modules, there is always a temperature difference. Even if voltage balancing is conducted, deviations between the state of health (SoH) and state of charge (SoC) always exist. Therefore, a battery characteristic should be considered in relation to the efficient operation of an ESS. In this paper, charging control is implemented based on the SoC. When errors occur in the beginning, the coulomb counting method (CCM) continues to produce errors; it also calculates the SoC through an improved equation. Thus, it can calculate the SoC by using high-accuracy initial values. Moreover, battery deterioration occurs during charging and discharging, which increases a battery’s internal resistance. This reduces the switching time to the battery cut-off voltage or constant voltage (CV) mode, so it becomes possible to calculate the SoH. Therefore, in this paper, the algorithms and equations are proposed to perform SoH operations according to the charging time that is able to reach CV after charging. A conventional battery is usually charged by using constant current (CC) charging until the voltage of the battery module reaches the cut-off area. A switch to CV then occurs when the cut-off area is reached and maintained. However, SoC-based selective charging control is carried out to prevent heat problems. In addition, the battery is charged safely and efficiently by conducting SoH prediction considering the battery thermal characteristics, which vary depending on the charging time and other characteristics. In this paper, a 3 kW ESS was produced, and the proposed algorithm’s feasibility was verified.

Transit Holding Control Model for Real-Time Connection Protection

The time required to transfer between different transit lines is a critical component of passenger travel time. Although transit agencies attempt to design well-coordinated timetables among intersecting lines at the scheduling stage, an operational control method is necessary to maintain the coordinated transfers that may occasionally be disrupted due to unexpected delays of public transit (PT) vehicles. One possible and practical approach is Connection Protection (CP), which involves holding a transit unit in order to wait for another transit unit that is planned to provide a coordinated transfer but has been delayed. This study develops a CP model to apply holding control to a receiving vehicle trip for the purpose of protecting the scheduled connection against delay of a feeder trip. The study incorporates the probabilistic nature of transit operations in formulating the cost function of the model, and accordingly makes more robust decisions for controlling the PT system. The developed model is evaluated by means of a sensitivity analysis. The results show that the model improves transfer efficiency and reduces the waiting times of affected passengers while minimizing delays to other passengers.

Operation Optimization and Control Method Based on Optimal Energy and Hydrogen Consumption for the Fuel Cell/Supercapacitor Hybrid Tram

In order to reduce the operation and maintenance cost of the tram on the fixed line, this article proposes a global optimal operation and control method based on the fuel cell/supercapacitor hybrid tram in each section between stations. This method consists of two parts: the speed optimization method based on the minimal energy consumption, and the hybrid system control method based on the minimal hydrogen consumption. For the speed optimization method, according to the energy consumption function of the tram in different operating stages, the distribution of the energy consumption of each section is obtained, and then the speed curve under the optimal energy consumption distribution can be further obtained; for the hybrid system control method, based on the energy distribution of the tram in each section, as well as the hydrogen consumption function of the fuel cell system (FCS), the optimal output power curve of the hybrid system is obtained based on the Lagrangian algorithm. Finally, according to the testing on the actual line, the results show that the proposed method can realize the online control of the tram, and has a significant effect on the hydrogen consumption and the output volatility of the FCS.

Research on operation control of low-voltage MTDC system in a cyber-physical environment

Cyber-physical system is becoming a new feature and hot topic in the development of smart grid and DC power distribution system. Based on the standardized cyber-physical modeling and communication system — IEC 61850, this paper establishes the operation control architecture of the low-voltage multi-terminal DC (LV-MTDC) system. The coordinated operation control strategies including power electronic transformer (PET), voltage source converter (VSC) is proposed. Then a cyber-physical model of the system based on IEC 61850 is built, according to the application requirements of operation control in the LV-MTDC system. On this basis, the implementation method of system operation control based on IEC 61850 is proposed, including the software/hardware design of intelligent electronic device (IED), dispatching operation and uninterrupted power supply. The simulation environment is further built to verify the system operation control technology, and the test platform is used to carry out the actual tests. The research results show that the operation control technology for the LV-MTDC system proposed in this paper is feasible, which can guarantee the rapid and accurate information exchange of control commands and settings, and thus effectively realize the operation control of the LV-MTDC system under complex conditions.

Methods and means of increasing the reliability of computerized modular uninterruptible power supply system

The problem of development and implementation of a simple and effective method of the rectifiers operation control for the modular uninterruptible DC power supply unit in order to increase its reliability is considered in this paper. The main idea of the method is to control the process of cyclic shifting of the switched-on power modules of the uninterruptible power supply by series switching into operation of each subsequent module from their unloaded reserve and switching out the previous one. The paper presents the control system structure where in addition to the central control module, it is proposed to add the control unit for power modules, which is responsible for implementing the process of their switching on and monitors their condition. In order to investigate the effectiveness of the proposed method, computer simulation model describing the power modules control logic is developed. The Simulink visual modeling environment and the mathematical tools of the Stateflow library component using state and transition diagrams are used in order to develop the simulation model. The developed simulation model is tested and the simulation results are given in the form of time diagrams of state change. The іmplementation of the developed method, due to the uniform reduction of the period during which the power modules of the uninterruptible power supply are on the switched-on loaded state, makes it possible to increase their operating time to failure, which in turn increases its reliability without deteriorating energy efficiency. The simulation results demonstrate the efficiency of the developed algorithm in various system operation modes. Based on the proposed method, hardware and software which is implemented as a part of intelligent computerized control system for uninterruptible DC power supply is created.

Research on airline operational risk management and control method

Starting from the reality of airlines, this paper studies the operational risk and control methods of airlines, establishes relevant risk index system, and formulates corresponding control methods. Based on the four aspects of human, aircraft, environment and management, the risk index system is established. The weight of the index and the score of each system are determined by using the analytic hierarchy process and the fuzzy comprehensive evaluation respectively, and the airline risk evaluation model is established. In the formulation of airline management and control methods, genetic algorithm is used to compare different flight task combinations, and the advantages of this method are obtained.

Power Retailer Air-Conditioning Load Aggregation Operation Control Method and Demand Response

Thermostatically controlled loads (TCLs) have become a major tool for the demand response (DR) program when air conditioners cause peak loads in a day during the winter or summer. To solve the problem of a direct load control with TCL usually affecting user comfort and hardly considering responsiveness, a power retailer air-conditioning load aggregation operation control and demand response method was proposed in this research. From the perspective of a power retailer, a compensation mechanism for TCL was constructed, which was composed of a basic incentive program and an additional incentive program. The basic incentive program aimed to encourage users with a low response degree to increase the response capacity in order to participate in DR. An auxiliary service market control strategy based on a new compensation mechanism of the electricity retailer was detailed, which fully considered the enthusiasm of the user in mobilizing the response and reducing the load reduction fluctuation when using the state-queuing (SQ) model. Case studies were provided to verify the effectiveness of the proposed method. Compared with other compensation schemes, the simulation results showed that the compensation mechanism provided in this research was more reasonable, and it could smooth the load and reduce fluctuations. The compensation distribution among the user groups could effectively control the uniform distribution in the user groups in the temperature range, and it could mobilize users at different temperatures to participate in DR.

Integrated headway and bus priority control in transit corridors with bidirectional lane segments

The problem of operating exclusive bus corridors that have segments with bidirectional lanes is treated. On these lanes, only one direction of movement is allowed when a bus is present. Such construct requires less road space, which is a scarce resource in dense urban areas, and thus may be the only feasible alternative for the installation of exclusive bus corridors. The system model includes limits on bus passenger capacity. The control method for real-time operation integrates bus headway corrections and bus priority through signalized intersections, while enforcing mutual exclusion of opposing buses on the bidirectional lanes. Effectively, the control avoids bus bunching over the entire corridor and coordinates the passage of opposing buses on bidirectional lanes. The objective is to minimize the total waiting time of passengers, both onboard and at stops. Simulation results indicate the applicability of the integrated holding and priority bidirectional lane control method.