Dynamic Mode Of Operation Research Articles

Cyclic Convolutional Neural Network Model Based on Artificial Intelligence

Abstract This paper mainly discusses the internal correlation between meshless discrete data and learning samples, meshless dynamic analysis recursive operation and information transmission mode in cyclic convolutional neural networks. This paper establishes a cyclic convolutional neural network based on the meshless method. This paper demonstrates an agent model of cyclic convolutional neural network based on dynamic characteristics. This method combines the advantages of the flexible configuration of meshless nodes in the discrete model. The universality and adaptability of cyclic convolutional neural networks are improved. In addition, because of the unique historical memory characteristics of the periodic module, it can analyze continuous data efficiently. The solution of dynamic analysis is accelerated without affecting the calculation accuracy. Based on a group of examples, the accuracy and effectiveness of this method are studied experimentally.

Customization of an atomic force microscope for multidimensional measurements under environmental conditions.

Atomic force microscopy (AFM) is an analytical surface characterization tool that reveals the surface topography at a nanometer length scale while probing local chemical, mechanical, and even electronic sample properties. Both contact (performed with a constant deflection of the cantilever probe) and dynamic operation modes (enabled by demodulation of the oscillation signal under tip-sample interaction) can be employed to conduct AFM-based measurements. Although surface topography is accessible regardless of the operation mode, the resolution and the availability of the quantified surface properties depend on the mode of operation. However, advanced imaging techniques, such as frequency modulation, to achieve high resolution, quantitative surface properties are not implemented in many commercial systems. Here, we show the step-by-step customization of an atomic force microscope. The original system was capable of surface topography and basic force spectroscopy measurements while employing environmental control, such as temperature variation of the sample/tip, etc. We upgraded this original setup with additional hardware (e.g., a lock-in amplifier with phase-locked loop capacity, a high-voltage amplifier, and a new controller) and software integration while utilizing its environmental control features. We show the capabilities of the customized system with frequency modulation-based topography experiments and automated voltage and/or distance spectroscopy, time-resolved AFM, and two-dimensional force spectroscopy measurements under ambient conditions. We also illustrate the enhanced stability of the setup with active topography and frequency drift corrections. We believe that our methodology can be useful for the customization and automation of other scanning probe systems.

Design, Development and Testing of a Monitoring System for the Study of Proton Exchange Fuel Cells and Stacks.

This article is about the design, development and validation of a new monitoring architecture for individual cells and stacks to facilitate the study of proton exchange fuel cells. The system consists of four main elements: input signals, signal processing boards, analogue-to-digital converters (ADCs) and a master terminal unit (MTU). The latter integrates a high-level graphic user interface (GUI) software developed by National Instruments LABVIEW, while the ADCs are based on three digital acquisition units (DAQs). Graphs showing the temperature, currents and voltages in individual cells as well as stacks are integrated for ease of reference. The system validation was carried out both in static and dynamic modes of operation using a Ballard Nexa 1.2 kW fuel cell fed by a hydrogen cylinder, with a Prodigit 32612 electronic load at the output. The system was able to measure the voltage distributions of individual cells, and temperatures at different equidistant points of the stack both with and without an external load, validating its use as an indispensable tool for the study and characterization of these systems.

Progress of the Evaluation and Analysis Methods for Durability of SOFC Stacks

Recent progress in the development of R&D for the evaluation and analytical methods of SOFC stack durability is reported under the NEDO Japanese national project. The goal of this project is the following two points: (1) to develop the advanced evaluation and analytical methods for the cell stacks which show a lifetime over 15 years (130 kh) with high efficiency of over 65% LHV, and (2) to develop the evaluation and analytical methods for dynamic operation mode such as rapid start-stop and load cycling. Three practical stacks (one flat tube and two types of planar) were supplied by the stack developers and tested over 10,000 hours with high fuel utilization (Uf~85%). It was found that the same evaluation methods can be applied to the stack resistance component determination between normal Uf (=75%) and high Uf (85%) conditions. Relatively stable performances were reported for these stacks and degradation factors were considered taking into account the degradation mechanisms at cells and stacks. Under high Uf conditions, some specific degradation mechanisms are now analyzed in the cells. For rapid starts of stacks, evaluation protocols are considered taking into account the mechanical stress arising from the thermal distribution in the cells. Simulation methods are considered for the evaluation of performance after 15 years of operation in the stacks.

A Novel Coil Architecture for Interoperability and Tolerance to Misalignment in Electric Vehicle WPT

In this contribution the authors investigate a modular structure of Wireless Power Transfer system specifically dedicated to a quasistatic or dynamic operation mode in an urban environment. The proposed architecture has been simulated by using a commercial software. Characteristics of the interoperability are analyzed when the modular transmitting and receiving coils are in proximity, and the architecture has proven to be characterized by excellent performances in terms of small interaction between each single module. Finally, an improved coil design has been introduced which is characterized by good uniformity of the coupling coefficient when the receiver travels between two adjacent transmitting sections.

Synthesizing the Optimal Control of an Induction Motor-Based Traction Electric Drive with Taking into Account Magnetic Saturation and Core Losses

Traction electric drives based on an induction motor often employ vector control with orienting along the rotor flux vector, with which it becomes possible to achieve high performance indicators of the motor and drive as a whole in both static and dynamic operation modes. However, to achieve high energy efficiency of the drive, the use of optimal control strategies becomes of issue. This implies the need to set up, given a specified electromagnetic torque, the stator current flux-forming and torque-forming components according to a certain law to achieve the motor operation optimized with respect to the selected criterion. In the context of a traction electric drive, such criteria are stator current to be maximized or power losses to be minimized. In doing so, it is important to take into account the motor magnetic system saturation and core losses, which have a significant impact on the synthesis of optimal control strategies. The article gives the equations of electromagnetic processes in a cage induction motor with field-oriented control and with taking into account the above-mentioned specific features. A procedure for synthesizing optimal control strategies while minimizing power losses and stator current is also given. Differences in approaches to the synthesis of optimal strategies with and without taking the magnetic system saturation into account are shown.

Increasing the energy efficiency of modes of distribution networks with photovoltaic stations

Purpose. Establishing the regularities of changes in influence of power quality indicators caused by the operating modes of photovoltaic (PV) station inverters on the operating modes of distribution networks’ equipment to improve their energy efficiency by reducing power losses. Methodology. To solve the scientific problems, the following methods are used such as: the method of harmonic analysis (Fourier integral); decomposition of the current spectrum by amplitude-frequency component using Mdaq-14 hardware and software platforms and LabVIEW software; the method of data correlation analysis to determine the higher harmonic current dependence on the load of an on-grid inverter; mathematical and physical modeling in the development of a way to improve the energy efficiency of on-grid inverters of PV stations. Findings. The conducted studies on electromagnetic compatibility indicators of grid photovoltaic station inverters in stationary and dynamic operation modes made it possible to establish the characteristic regularities of changes in the spectrum and amplitudes of higher harmonic components depending on the level of inverter loading. Hyperbolic dependences of the change in the sinusoidal signal distortion coefficients of the harmonic component on the level of inverter loading were experimentally established. A method has been developed for reducing the electromagnetic interference levels caused by photovoltaic station converters by implementing a circuit solution and algorithm for loading on-grid inverters in non-stationary modes in order to improve their electromagnetic compatibility and increase the energy efficiency of distribution networks with appropriate decentralized sources. Originality. The regularities are established of influence of the operating mode’s parameters of photovoltaic station inverters on the indicators of electromagnetic compatibility in their power supply system, including taking into account special circuit solutions, which allows increasing the energy efficiency of distribution network modes. Practical value. The method for reducing the electromagnetic interference levels generated by photovoltaic station inverters by implementing the proposed circuit solution and algorithm for loading the on-grid inverters in non-stationary modes is universal and can be applied to any photovoltaic station. This will help to reduce the power losses and electromagnetic damage to equipment from the action of higher harmonic components. Granting the established regularities of higher harmonics influence will allow one to take into account the impact of the relevant indicators on the additional insulation heating of power supply system elements and to assess the corresponding electromagnetic damage, to provide recommendations for consideration of the modes in calculating methods and PV equipment selection.

Hygrothermal behaviour of a room with different occupancy scenarios

The thermal and moisture properties of building partitions and the related possibility of moisture buffering affect the water vapour exchange between the superficial layers of the hygroscopic materials and the indoor environment, which results in energy consumption for different purposes. The paper describes an analysis of the hygrothermal behaviour of a roomunder different occupancy scenarios for four wall finishing variants (variable parameters of thermal conductivity index and diffusion resistance of the applied material). The application of gypsum board and cement-lime plaster was analysed with and without a paint coat. Computer simulations using WUFI Plus were used for the analysis. The application of cement-lime plaster without a top paint coat was shown to reduce fluctuations in the amplitude of indoor relative humidity more than the other solutions. Applying a paint coat to the interior surface of a building partition limits the material's buffering properties, and consequently, the indoor relative humidity amplitude increases. Upon improving thermal efficiency, the decrease in indoor relative humidity was higher for a nursery than for an office space. For the air conditioning dynamic operation mode, it was demonstrated that gypsum board walls with no paint coat could reduce energy demand for dehumidifying systems and increase it for humidifying systems. The painted variants are characterised by a higher total energy consumption for humidification and dehumidification purposes.

Modeling of Dynamic Operation Modes of IVG.1M Reactor

This paper presents the results of a calculation code approach providing a solution to the point kinetics problem for the IVG.1M research reactor of the National Nuclear Center of the Republic of Kazakhstan and allowing the simulation of dynamic processes going on during reactor start-ups, including changes in the thermal state of all its elements, reactor regulator displacement, accumulation of absorbers in the fuel, and the beryllium reflector. A mathematical description of the IVG.1M point kinetics model is presented, which provides a calculation of the reactor neutron parameters, taking into account the dependence of reactivity effects on the temperature, changes in the isotopic composition of materials, and thermal expansion of core structural elements. An array of data values was formed of reactivity added by separate elements of the core when changing their thermal state and other reactor parameters, as well as an array of data with the parameters of heat exchange of coolant-based reactor structural elements. These are used in the process of solving the point kinetics problem to directly replace formal parameters, eliminating the need to calculate the values of these parameters at each calculation step. Preliminary calculations to form an array of values of reactivity effects was applied to the reactor by separate structural elements when their temperature changes were performed using the IVG.1M precision reactor calculation model. The model was validated by the reactor parameters in the critical state. Preliminary calculations to form an array of data with the parameters of heat exchange of coolant-based reactor structural elements were performed in ANSYS Fluent software using the calculation model that describes the IVG.1M reactor fuel element in detail. Validation of the developed calculation code based on the results of two start-ups of the IVG.1M reactor was performed and its applicability for the analysis of transient and emergency modes of reactor operation and evaluation of its safe operation limits was confirmed.

Calculation of dynamic operating modes refrigeration machines with electric energy sources

The method of calculating the dynamic operating modes of refrigerating machines with electric power sources is described. As an example, the results of the calculation and data of experimental studies of the processes of starting a refrigerating machine with an electric asynchronous motor are given.

Analysis of the possibility of using additive technologies in basic parts manufacturing

The purpose of the article is to choose a selective laser sintering method suitable for basic parts manufacturing, as well as to analyze mechanical characteristics of parts obtained using selective laser sintering, depending on the technology of their production. Basic parts manufacturing is a complex and expensive process which includes casting or welding, milling of base surfaces, and boring of holes. As a rule, body is the largest part of the structure, and accuracy of its base surfaces manufacturing directly affects performance of the entire mechanism. Method of producing blank parts is of paramount importance in body manufacturing. Parts of this type must ensure precision of the relative position of individual elements, both at rest and in the dynamic mode of machine operation. At the same time, it is known that all methods of blank parts production are characterized by the presence of residual stresses in the blank part. Gradually relaxing, these stresses “come out” in the form of deformations, which leads to displacement of parts and units of the entire mechanism, and a change in their interaction. This directly affects performance and resource of the entire machine.

АНАЛІЗ СИСТЕМИ ПАРАЛЕЛЬНОГО НЕЙРОУПРАВЛІННЯ ДИНАМІЧНИМИ ОБ'ЄКТАМИ

The article analyzes the effectiveness of the neural network control system, which together with the PIDcontroller implements the principle of parallel control of a dynamic object. As a rule, most industrialfacilities are characterized by non-linear dependencies, the presence of uncontrolled noise anddisturbances, frequent changes in equipment operating modes, and the presence of significant non-linearities. The model of the blowing subsystem of a water-tube steam boiler was used as an object ofresearch. The training of the neural network controller (NMC) and neuroemulator (emulator) was carriedout on the ACS model with a PID controller using the method of expert adjustment of tuning coefficients:proportionality, constant integration and differentiation based on the analysis of the quality indicators ofthe transition process. The change in the values of the object model parameters along the control anddisturbance channels corresponded to the dynamic modes of operation of the steam boiler in the range ofsteam load (25-110%) from the nominal one. The analysis of transient processes obtained on the basis ofcomputer modeling allows us to assert that the trained neural network control system compensates fordisturbances over the entire range of changes in the values of the object parameters along the control anddisturbance channels (simulation of changes in the steam load), as well as when the parameter values ofthe models go beyond the range study sample. Thus, the neural network controller can successfully perform the functions of an adaptive circuit tuned tothe most unfavorable disturbances in the ACS of parallel action by a complex production facility. And theimplementation of a neural network system of parallel action together with typical regulators in thetechnological processes of heat energy can reduce emergency situations associated with frequent changesin the steam load of power units caused by military actions in our country.

РАЗРАБОТКА СИСТЕМЫ УПРАВЛЕНИЯ ПОГРУЖНОГО ВЕНТИЛЬНОГО ЭЛЕКТРОПРИВОДА ЭЛЕКТРОБУРА

Due to the active development of the oil and gas service, the construction of oil and gas wells is becoming increasingly important for the economy of Russia. This work is aimed at developing a mathematical description and model of the control system of the valve electric drive of an electric drill, as well as analyzing the transient processes of the obtained system. The work presents a mathematical description of the dynamic modes of operation of the electric drive system with a synchronous machine with permanent magnets, and a structural diagram is built. Using the Matlab Simulink environment, a model of the system was built. Graphs of transient processes during start-up and load changes were obtained, based on which conclusions were drawn about the operation of the electric drill control system. It was found that the control system is capable of adapting and maintaining the speed at a given level when the load on the shaft and the control signal change.

Energy Flexibility in the Casting Industry Using Bivalent Machines

The German Federal Government aims for 100 % renewable energy-sourced electricity to transition into a low-carbon economy. Today's challenge is transitioning the system to integrate the highly fluctuating renewable wind and solar energies into the electric power system. The industrial sector can contribute to the transition by aligning electricity consumption with the supply. This has a big potential to improve the stability of the power grid. Energy and heat-intensive industries can achieve energy flexibility by changing the energy carrier during operation to adjust the required power. Hybridizing production systems with a second energy source, such as natural gas or hydrogen, is crucial for thermal processes like the magnesium die-casting. This article describes a modeling approach for the dynamic operating mode of a bivalent melting furnace. The model uses a load-related efficiency curve, which are based on the experience of furnace manufacturers and published articles. The model investigates several measures to increase energy flexibility, such as the change of energy carrier according to energy prices, die furnace and organizational arrangements. The impact of these energy flexibility potentials on energy costs is evaluated, and the measures are compared.

A Multi-Mode 8k-MAC HW-Utilization-Aware Neural Processing Unit With a Unified Multi-Precision Datapath in 4-nm Flagship Mobile SoC

This article presents an 8k-multiply-accumulate (MAC) neural processing unit (NPU) in 4-nm mobile system-on-chip (SoC). The unified multi-precision MACs support from integer (INT)4/8/16 to floating point (FP)16 data with high area and energy efficiency. When the NPU meets some layers having low hardware (HW) utilization, such as depthwise convolution or shallow layers with a few input channels, the NPU reconfigures the computational flow to enhance the utilization up to four times after getting basic tensor information from a compiler, such as operation types and shapes. The NPU supports a dynamic operation mode to cover extremely low-power to low-latency requirements. The NPU achieves 4.26 tera FP operations per second (TFLOPS)/W and 11.59 tera operations per second (TOPS)/W for DeepLabV3 (FP16) and MobileNetEdgeTPU (INT8), respectively, as well as high area efficiency (1.72 TFLOPS/mm2 and 3.45 TOPS/mm2).

INVESTIGATION OF THE OPERATION MODES OF THE BELT-ROPE CONVEYOR ELECTROMECHANICAL SYSTEM WITH VECTOR-CONTROLLED INDUCTION ELECTRIC MOTORS

Continuous transport systems are the most promising type of movement of loose and artificial materials, have high productivity, technical and economic indicators and are widely used in world practice as main conveyors for the coal and mining industry. A special place in continuous transport is occupied by belt-rope conveyors, which are capable of transporting cargo over a distance of more than 30 km in one stop. As a rule, these main conveyors do not provide for the adjustment of movement parameters, the start is carried out using soft start systems. At the same time, such systems have high requirements for the parameters of dynamic modes of operation, the accuracy of working out the given movement program and the level of energy efficiency. The paper proposes a modern electric drive system using vector-controlled induction electric motors. The structure of the electromechanical system is given. A mathematical model of the electromechanical system was built using known methods. As part of the “MATLAB” Simulink application program package, a model for the investigation of dynamic modes of conveyor operation was obtained. On a specific example, a research of dynamic and static modes of conveyor operation with static load and the speed of movement variations of the traction element was carried out. Studies of the accuracy of working out the given law of motion showed that the maximum dynamic error in terms of speed and current is worked out in a time of up to 0.06 s. The maximum level of its amplitude does not exceed 0.33% of the constant speed of movement, which does not cause oscillatory processes in the conveyor and ensures stable operation of the electromechanical system. Investigation of the electromechanical system energy characteristics was conducted. Losses of active power do not exceed 12.5% of the consumed in the entire range of variation of the static load and speed of the traction element. Recommendations for the use of electromechanical systems with vector-controlled induction electric motors in belt-rope conveyors have been formulated.

Modified Dual Mode Transmission Gate Diffusion Input Logic for Improving Energy Efficiency

This paper presents a modified energy-efficient Dual Mode Transmission Gate Diffusion Input (DMTGDI) design and is termed as M-DMTGDI. A contention issue in dynamic mode operation of existing DMTGDI design and DMPL design is identified and illustrated through mathematical formulation and simulations. To resolve this concern, the pre-charge/pre-discharge transistor in existing DMTGDI design is replaced by dual mode inverter in the proposal. The functional verification and performance comparison of NAND, NOR, XOR gates and 1-bit full adder based on proposed M-DMTGDI is carried out using 90 nm BSIM4 model card for bulk CMOS using Symica DE tool. The performance of the circuits is evaluated in terms of power, delay and Power Delay Product (PDP) in both static and dynamic modes. The variation of PDP with the ratio of the time the circuit is designed to run in dynamic mode against static mode is also investigated to analyze the energy efficiency of the M-DMTGDI design. The proposed approach offers maximum PDP reduction of 33.52%, 99.39% and 96.61% for 2-input gates as compared to their footed DML, DMPL and DMTGDI counterparts, respectively. The reduction in PDP is quite significant in 1-bit full adder circuit where the corresponding values are 94.18%, 99.41% and 99.79%, respectively.

Имитационное моделирование адаптивного идентификатора скорости асинхронного двигателя агломерационной машины

By means of simulation computer modeling, an effective variant of constructing an identifier for the speed of an asynchronous motor of an electromechanical system of a sintering machine is analyzed. The mathematical and algorithmic basis of the adaptive speed identifier (ASI) of an induction motor with a squirrel-cage rotor (ACIM) is given. Using the developed mathematical description of ASI with a reference model and using the apparatus of Lyapunov functions, an adequate computer simulation model was created. Compared with the existing methods for constructing identifiers in sensorless asynchronous electric drives, the proposed version of the ASI allows taking into account the discrete nature of the supply voltage of the ACIM at the output of the frequency converter with pulse-width modulation (PWM) of the output voltage and changing a larger number of equivalent circuit parameters. The stability of the speed identification process is provided in a wide range, sufficient to stabilize the speed of the trolleys according to the requirements of the technological process of sintering machines. As a result, the accuracy of speed identification in static and dynamic modes of operation of the electric drive increases. Simulation confirmed the operability of the proposed version of the identifier, proposed options for setting the AIS components. Universal, important for practical application results have been obtained, which allow both to build a high-precision system for identifying the ACIM speed in general and to refine the setting of the coefficients of the proposed version of the identifier in particular. An important property of the developed version of the ASI is its operability without loss of accuracy at near-zero and zero speeds of rotation and close to the nominal load torque on the ACIM shaft. In this regard, the practical application of the developed version, in addition to the drive of the sintering machine, is also possible in high- precision positioning systems for electric drives for various purposes.

Harmonic Content-Based Protection Method for Microgrids via 1-Dimensional Recursive Median Filtering Algorithm

Microgrids (MGs) offers grid-connected (GC) and islanded (ID) operational modes. However, these dynamic modes of operation pose different microgrid protection challenges. This paper presents a new protection method for MGs based on a discrete one-dimensional recursive Median filter (1-DRMF). In the first step, the 1-DRMF is applied on a measured current signal on every single phase individually for targeted feature extraction. Then, the median filter deviation (MFD) and the selected harmonic distortion (SHD) are computed from the current signals of all phases independently. In the second step, the upsurges in the MFD and the SHD of all phases are cross-checked with the pre-established threshold value of 0.3 to identify and categorize fault incidents. Finally, the directional properties of three-phase (3-p) reactive energy are employed in order to pinpoint the faulty line section (LS). Many simulations were executed on MATLAB/Simulink to validate the sustainable performance of the established method. Results prove that the scheme can detect, classify, and locate the solid and high impedance faults (HIF) in the GC as well as the ID modes under radial and meshed scenarios.

Direct Deadbeat Control of a Buck PWM Converter

The paper explains the shortcomings of the well-known modal control strategy, which prevent its practical application to achieve the highest possible dynamic performance of switching semiconductor converters. A method for eliminating these shortcomings is suggested as applied to a self-contained modal control version with specifying zero roots of the characteristic polynomial and obtaining a nilpotent system matrix. A technique for synthesizing direct deadbeat control with a nilpotent system matrix is described in detail to implement a finite transient that terminates within a number of cycles not exceeding the order of the difference equation with which a discrete system is described. The control object is a well-known circuit of a DC-DC buck converter with an inductive-capacitive filter and a proportional input-output characteristic provided by an integral link in the feedback loop. The efficiency of the proposed deadbeat controller version is confirmed through mathematically simulating the operation of a PWM converter controlling the load current. The dynamic operation modes are studied for the case of a step change in the load resistance and input voltage relative to their nominal values for a control system with I-, PI- and deadbeat controllers. A comparison of the obtained results shows that the transients in the system equipped with a deadbeat controller terminate most quickly: within three cycles without an overshoot. This corresponds to the maximum convergence rate to the equilibrium state for a third-order system.