Simulation Of Complete System Research Articles

Research on the new control strategy of the three-phase VIENNA rectifier

Abstract The VIENNA rectifier has long been used in applications such as charging piles, and the theoretical research on its control strategy is enumerated. Compared with other circuit components, the VIENNA rectifier has fewer power components and a higher power factor, so it is applied to more application scenarios. The traditional PI control has a long start-up response time and a high overshoot, while the sliding mode control (SMC) has excellent control performance for nonlinear systems. In my article, the control mode of the VIENNA rectifier is analyzed mathematically, SMC takes controls of the current inner loop, and a new exponential reaching rate is put forward the at first improve the control process. Finally, a complete system simulation model is built to prove the superiority of the VIENNA rectifier based on an optimized SMC control strategy for each control target and the corresponding control strategy. The results show that the control effect is obviously optimized by using this method.

Numerical simulation of a hybrid energy system proposed for low carbon data center

Low-carbon energy application for both large grid and distributed energy consumers is an urgent problem to be solved. Data centers (DC) are the typical distributed large-size energy consumers, and the application of renewable energy and energy storage is a promising solution for data center decarbonization. This paper developed a complete hybrid energy system (HES) simulation process for data center applications. The photovoltaic (PV) cell, hydrogen electrolysis, hydrogen storage, proton exchange membrane fuel cell (PEMFC), lithium battery (BAT), grid, and data center load are considered in the HES. A one-dimensional two-phase flow PEMFC model is developed. The detailed mass transfer process inside the PEMFC cell is modeled. The PEMFC model-solving algorithm is developed and integrated into the HES simulation program. The energy management system (EMS) based on a logical flow chart energy management strategy is integrated by editable subfunction. The HES simulation program is coded and implemented based on the MATLAB-SIMULINK environment. The yearly HES performance simulations are conducted and analyzed for a 200 kW data center in Xi’an with different HES parameters and an appropriate HES parameter arrangement is provided. The main contribution of this work is the development of an editable HES simulation program that is extensible for data center applications.

Development of generalized photovoltaic model using ISIS-PROTEUS

Photovoltaic (PV) energy is a form of renewable energy that generates electricity from sunlight. PV systems consist of solar cells, which convert sunlight into electricity using a process known as the photovoltaic effect. Modeling and simulating PV systems involves using mathematical and computational models to predict the behavior and performance of PV systems under various conditions. This can include modeling the electrical characteristics of solar cells, as well as the interactions between multiple cells in a PV module or system. Following this sense, we present in this work a novel implementation of a generalized PV model using ISIS Proteus software. Proteus is layout software for electronic circuit simulation, schematic capture and PCB design. Some studies have indeed taken this context to model the PV modules either by using a Proteus Spice model of the photovoltaic panel without including the effect of climatic conditions variation, or by using pure mathematical relations that describe all physical and environmental parameters which will lead to a static behavior. The developed model in this paper as it is generalized, can be typically used as a PV cell, module even a generator for a complete simulation of a PV system. PV cell, which is the elementary component of PV system, is modeled using the single diode equivalent circuit (SDM) also known as five-parameter model and its behavior is simulated in details. The most advantage in our study is the fact that the PV output can be obtained wherever what solar radiation and ambient temperature where PV module is operating. Our model gives also the possibility to simulate a dynamic behavior under any climatic conditions. The accuracy between obtained results of simulation and the experimental data confirm the reliability and the high performance of the developed model.

A Multi-Channel Data Simulator Based on the Time Unification System

In satellite and airborne electro-optical tracking systems, there are numerous processing devices and complex data flows. To ensure the coordinated operation of the system, the multiple devices within the target system must operate under unified time control for data acquisition, computation, and output. This study introduces a multi-channel data simulator based on a time unification system. The complete simulation system includes the host computer, simulator, target system, and time reference generator. The simulator has programmable input and output interfaces for multi-channel protocols and has storage and real-time working modes. In the storage mode, the simulated data are pre-transmitted to the simulator’s storage and sent to the target system according to the time reference generator. The simulator simultaneously stores the target system results. In the real-time mode, the host computer generates simulated data based on the target system’s results and outputs the data through the simulator in real time. The main contribution of the simulator is that it achieves system-level closed-loop simulation and completes the functional and performance verification of the target system. Through experimental verification, it is found that the simulator can achieve 4.2 Gbps of simulated data transmission and 1.6 Gbps of data reception and storage, with a closed-loop delay of 39.9 µs.

Three-phase four wire shunt active power filter based on Simplified Backstepping technique for DC voltage control

This work presents a simulation of Three-Phase Four-Wire Shunt Active Power Filter (SAPF) destined to suppress harmonic currents generated by nonlinear loads. The SAPF guarantee also the compensation for unbalanced nonlinear load currents, reactive power and harmonic neutral current. The identification method is based on the synchronous reference frame. In order to have good performances of DC voltage control, simplified Backstepping control for three-Phase four-Wire (SAPF) system is proposed. Complete simulation of the resultant active filtering system validates the efficiency of the proposed simplified Backstepping control law over to the traditional control with PI controller.

Low-frequency operation control method for medium-voltage high-capacity FC-MMC type frequency converter

The application of modular multilevel converters (MMCs) to large drive systems is subject to severe low-frequency operation restrictions. The fluctuation of capacitor voltage and the high amplitude of common mode voltage in sub-modules is a thorny problem. In this paper, a novel fly-across capacitor modular multilevel converter topology is adopted to eliminate low-frequency voltage ripples by using the fly-across capacitor as a power transfer channel between the upper and lower bridge arms of the MMC. A novel finite compensation method is proposed—instead of the traditional full compensation method—that introduces a real-time variable limiting factor to change the amplitude of the mixed injected high-frequency differential-mode voltage and high-frequency differential-mode current and reduce the amplitude of the common-mode voltage on the AC side while lowering the current stress of the power devices. Finally, a complete system simulation model is constructed, and the topology with the proposed control strategy are verified to have good output characteristics under different operating conditions; good results are achieved in suppressing the sub-module fluctuation and common-mode voltage.

Gamma Knife Icon™ Single Sector Characterization Based on Monte Carlo Simulation

Purpose: Gamma Knife Radiosurgery refers to surgery using radiation to destroy intracranial tissues or lesions elusive or unsuitable for open surgery. This study aimed to simulate the Gamma Knife Icon™ (GKI™) single sector to assess various attributes of the output beam and evaluate the EGSnrc C++ Monte Carlo code capabilities to perform a complete simulation of GKI™ for more investigations.
 Materials and Methods: The single source is simulated, and the geometries of the 4 and 16 mm collimators are defined based on the manufacturer data. The phase space files (PSFs) are recorded at the end of each collimator, and dose distributions are saved for the final analysis process in the last step.
 Results: The beam spectrum has two energy peaks g1 =1.17 MeV and g2 = 1.33 MeV, and low energy photons from scattering are also evident. The Gamma Index (GI) values are less than 1 in comparing the dose profiles generated in simulation with reference data. The Full Width at Half Maximum (FWHM) is 4.55, 10.9, 5.13 (mm) and 16.7, 35.1, 17.65 (mm) for 4mm and 16 mm collimators along x, y, and z axes, respectively. The penumbra width (80%-20%) is also 1.48, 5.5, 1.54 (mm) and 3.76, 10.1, 2.78 (mm) for 4mm and 16 mm collimators along x, y, and z axes, respectively.
 Conclusion: Results are in good agreement with what is expected, and it is possible to perform a complete simulation of the GKI™ system using egs++ for more investigations in phantoms and patients.

Quasi-optical design of a millimeter wave imaging system

We report a complete design and simulation of a quasi-optical millimeter wave imaging system using ZEMAX and FEKO software, respectively. A Fresnel lens and a horn antenna are combined in this design. Compared to spherical and aspherical lenses, a Fresnel lens can be fabricated much easier at millimeter wavelengths. For focusing millimeter wave radiation, a Fresnel lens can be used to reduce the thickness of the focusing element and to lighten its weight from 25 to 4.5 kg. A horn antenna with a Gaussian profile and corrugated walls is designed for feeding this system at a central frequency of 94 GHz. The symmetrical radiation pattern of the designed corrugated Gaussian horn in E- and H-orthogonal planes, its wide bandwidth, and low side lobe levels make it a good candidate for feeding a W-band millimeter wave imaging system. The designed quasi-optical imaging system is light-weighted, has high resolution, and can be used in detecting hidden objects within a distance of 5 m with a 30-mm resolution in W-band at a central frequency of 94 GHz.

Optimal Sizing of Cylindrical Receivers for Surround Heliostat Fields Using fluxtracer

Abstract This article presents an innovative approach for optimizing the dimensions of cylindrical receivers for solar tower systems. In this approach, a single set of rays, representative of a complete annual ray-tracing simulation of the solar tower system, is used and processed to evaluate numerous receiver designs simultaneously and to select the optimum. The simultaneous evaluation of receiver designs is achieved by exploiting the geometrical properties of the intersection between a ray and a cylinder, which allows estimating the annual energy intercepted by receivers of different heights without the need for processing the annual set of rays more than one time. Once the annual intercepted energy is known for each receiver, the application of a costing function estimating the receiver cost as a function of its surface area allows to estimate their cost and, therefore, to select the receiver dimensions that will yield a minimum surface area for a given annual energy interception factor. The overall workflow to carry out the mentioned receiver optimization approach has been implemented by adapting several open-source tools that The Cyprus Institute (CyI) is developing in collaboration with the Australian National University (ANU) to assist in the modeling, analysis, design, and optimization of concentrated solar thermal (CST) systems. This article also presents a detailed overview of the overall simulation workflow as well as a case study demonstrating the capabilities of the approach.

Research on high precision tracking control technology of airborne laser weapon

The airborne laser weapon system is a kind of directional energy weapon system, which has a higher tracking accuracy requirement than other weapon systems, so that the traditional PID control cannot meet the requirements of high precision control. A compound axis servomechanism with preview model was used to build a complete simulation system, including detector model, fast mirror model and time delay model, etc. In order to improve the control accuracy, the active disturbance rejection control algorithm and the compound axis control structure were combined. The simulation system built in the article was verified by the function verification test of some transport disturbance data collected in practice. The results show that the tracking accuracy of the system is 5.16 μrad, which is 25 times of the traditional PID control. At the same time, a virtual battlefield scene was given, which was verified by the simulation system built in this paper. The tracking accuracy of pitch axis and yaw axis were both less than 10 μrad.

Theoretical Study on Cryogen Spray Cooling in Laser Treatment of Ota’s Nevus: Comparison and Optimization of R134a, R404A and R32

Cryogen spray cooling (CSC) could be applied clinically for the laser therapy of Ota’s nevus, a dermal hyperplastic pigmented disease with a morbidity rate of 0.1–0.6% in the Asian population. An accurate, efficient, complete simulation system that considers the entire spray cooling process, including cryogen flow in the tube nozzle, spray dynamics and internal phase change heat transfer (cold injury) in skin tissue, was established to determine suitable cryogen and cooling parameters. The optimum spray distances for R134a, R404A and R32 were determined to be 66.0, 43.1 and 22.5 mm, respectively. The corresponding maximum surface heat fluxes were 363.5, 459.9, and 603.6 kW∙m−2, respectively. The maximum surface heat flux of R32 with small spray distance was 1.66 times as large as that of R134a, indicating the potentially good cooling performance and precise targeted cooling of R32 during the laser therapy of Ota’s nevus. The cooling durations that caused cold injury of skin tissue were 2.3, 1.4, and 1.1 s for R134a, R404A, and R32, respectively. The interval between CSC and laser irradiation was optimized to 90–162 ms for R134a, R404A and R32, in consideration of the cooling effect, depth, uniformity, and risk of cold injury.

Modeling and Simulation of Perching With a Quadrotor Aerial Robot With Passive Bio-inspired Legs and Feet

Abstract Perching in unmanned aerial vehicles is appealing for reconnaissance, monitoring, communications, and charging. This paper focuses on modeling, simulation, and control of bioinspired perching in unmanned aerial vehicles on cylindrical objects, which will be used for future planning and control research. A modular approach is taken where the quadrotor, legs, feet, and toes are modeled separately and then integrated to form a complete simulation system. New models of these components consider kinematics and dynamics of each element and their coupling through tendons that provide actuation. The integrated model is assembled to simulate a physical prototype and then validated based upon physical experiments to provide calibration. Simulation results evaluate the validated model performing perching with different gripper-perch alignments. The simulation environment developed in this research provides a foundation to research control approaches for use with the discussed passive perching mechanism. The simulation was validated to capture the dynamics of the real perching mechanism. This platform will be used in future work to develop a control approach that will be implemented in a quadrotor system to land and take-off from a perch in a reliable manner.

Simulation of a machine vision system for reflective surface defect inspection based on ray tracing.

A complete simulation of a machine vision system aimed at defect inspection on a reflective surface is proposed by ray tracing. The simulated scene is composed of the camera model, surface reflectance property, and light intensity distribution along with their corresponding object geometries. A virtual reflective plane geometry with scratches of various directions and pits of various sizes is built as the sample. Its realistic image is obtained by Monte Carlo ray tracing. Compared to the pinhole camera model, the camera model with a finite aperture emits more rays to deliver physical imaging. The bidirectional reflectance distribution function is applied to describe the surface reflectance property. The illustrated machine vision system captures a number of images while translating the light tubes. Then the image sequence obtained by experiment or simulation is fused to generate a well-contrasted synthetic image for defect detection. A flexible fusion method based on differential images is introduced to enhance the defect contrast on a uniform flawless background. To improve detection efficiency, defect contrast of synthetic images obtained by various fusion methods is evaluated. Influence of total image number, light tube width, and fusion interval is further discussed to optimize the inspection process. Experiments on car painted surfaces have shown that the simulated parameters can instruct the setup of the optical system and detect surface defects efficiently. The proposed simulation is capable of saving great effort in carrying out experimental trials and making improvements on reflective surface defect inspection.

Three‐phase four‐wire shunt active power filter based on the SOGI filter and Lyapunov function for DC bus control

SummaryThe three‐phase four‐wire shunt active power filter (SAPF) was developed to suppress the harmonic currents generated by nonlinear loads, and for the compensation of unbalanced nonlinear load currents, reactive power, and the harmonic neutral current. In this work, we consider instantaneous reactive power theory (PQ theory) for reference current identification based on the following two algorithms: the classic low‐pass filter (LPF) and the second‐order generalized integrator (SOGI) filter. Furthermore, since an important process in SAPF control is the regulation of the DC bus voltage at the capacitor, a new controller based on the Lyapunov function is also proposed. A complete simulation of the resultant active filtering system confirms its validity, which uses the SOGI filter to extract the reference currents from the distorted line currents, compared with the traditional PQ theory based on LPF. In addition, the simulation performed also demonstrates the superiority of the proposed approach, for DC bus voltage control based on the Lyapunov function, compared with the traditional proportional‐integral (PI) controller. Both novel approaches contribute towards an improvement in the overall performance of the system, which consists of a small rise and settling time, a very low or nonexistent overshoot, and the minimization of the total harmonic distortion (THD).

Reactive Power Compensation in Distribution Systems Through the DSTATCOM Integration Based on the Bond Graph Domain

In this paper, the distribution static compensator model based on the bond graph (BG) domain is presented. The methodology is applied to reactive power compensation in distribution systems where a traditional phase lock loop for sensing the AC grid frequency is not needed. The control law is developed using the inverse BG model, which is extracted using the bi-causality concept. In this way, it is possible to perform the distribution system analysis completely in the BG domain. This means that the graphical model is inverted by obtaining the open-loop control law structure, and then the close loop is formulated. The balanced and unbalance conditions are analyzed, generating a control structure that is robust and efficient. The efficacy of the proposed methodology is shown through: partial and complete system simulations in MATLAB/Simulink® (MATLAB r2015b, Natick, Massachusetts, 01760, USA), as well as experimental laboratory tests. Such tests use: the rapid control prototyping concept and the real-time simulator Opal-RT Technologies® (Montreal, QC, Canada).

Small signal modelling and control of high gain coupled inductor boost inverter for solid oxide fuel cell based power generation system

Small signal model of high gain coupled inductor boost inverter is established in presented work. Developed small signal model is then integrated with the model of planar solid oxide fuel cell and simulation of complete system is realized using MATLAB/Simulink environment and compared with the already developed fuel cell-based power converters. Coupled inductor boost converter was chosen to achieve higher gain in dc link voltage by selecting the appropriate turn ratio. Small signal model for dc-dc and dc-ac stages is derived separately and accordingly control system is designed. Dual loop with feed forward control scheme for coupled inductor boost inverter resulted in good performance like stable dc link, fast transient response, low total harmonic distortion (THD) and input disturbance rejection. Mathematical analysis, simulation and hardware results prove the stability and reliability of the complete system.

Improving line-of-sight pointing accuracy of laser communication system based on Kalman filter

The size of the field of uncertainty (FOU) is an important performance indicator of spatial optical communication systems and is closely related to the line-of-sight (LOS) pointing accuracy. Considering the aircraft-ground laser communication as the research background, the initial pointing angle of the LOS of communication is obtained using the coordinate transformation matrix, and the factors that affect the LOS pointing accuracy error are analyzed. The Kalman filtering technique is introduced into the LOS pointing system to complete system modeling and simulation analysis. The simulation results show that the position, attitude angle, and other data fluctuations of global positioning system/inertial navigation system composite systems can be smoothed effectively by adding a Kalman filter to the LOS pointing system, and the prediction function of the filter can reduce the influence of dynamic lag. The proposed approach improves the accuracy of the LOS pointing, reduces the size of the FOU, and provides reference and guidance for the design of space optical communication systems.

Integration of automatic generated simulation models, machine control projects and management tools to support whole life cycle of industrial digital twins.

The paper presents a framework of automatic generation of industrial digital twins. These digital twins will be suitable to support preliminary design phases of systems development, but also to support next phases of detailed designs implementation and systems running phases. These digital twin allow, from the preliminary designing phase, to generate a complete simulation of the target industrial system. But, at the same time, and without the need to develop and add any subsequent code, they should be a valuable support for the phases and tasks of exploitation: maintenance, machine or system learning, etc. The problem is that the requirements for first development phases are much more generic than those for later phases. For this reason, instead of incorporating specificities in the simulation system, the framework takes advantage of the applications which are being developed for the implementation of the real system. In these applications (the control program and the decisions and the high level management system), the specificities have had to be taken into account. The system has been specialized in industrial transportation and warehouse systems which, although have a finite number or building objects, they have an infinite set of final configurations, very different one from each other. The paper presents an evaluation of current simulation platforms suitable to be used as part of the framework, and the digital twin industrial system generation framework itself. An example of application is as well presented.

A generative model of realistic brain cells with application to numerical simulation of the diffusion-weighted MR signal

To date, numerical simulations of the brain tissue have been limited by their lack of realism and flexibility. The purpose of this work is to propose a controlled and flexible generative model for brain cell morphology and an efficient computational pipeline for the reliable and robust simulation of realistic cellular structures with application to numerical simulation of intra-cellular diffusion-weighted MR (DW-MR) signal features. Inspired by the advances in computational neuroscience for modelling brain cells, we propose a generative model that enables users to simulate molecular diffusion within realistic digital brain cells, such as neurons, in a completely controlled and flexible fashion. We validate our new approach by showing an excellent match between the morphology (no statistically different 3D Sholl metrics, P > 0.05) and simulated intra-cellular DW-MR signal (mean relative difference < 2%) of the generated digital model of brain cells and those of digital reconstruction of real brain cells from available open-access databases. We demonstrate the versatility and potential of the framework by showing a select set of examples of relevance for the DW-MR community. The computational models introduced here are useful for synthesizing intra-cellular DW-MR signals, similar to those one might measure from brain metabolites DW-MRS experiments. They also provide the foundation for a more complete simulation system that will potentially include signals from extra-cellular compartments and exchange processes, necessary for synthesizing DW-MR signals of relevance for DW-MRI experiments.

Study on qualitative simulation technology of group safety behaviors and the related software platform

Abstract The qualitative simulation technology of group safety behaviors is very important for investigating the laws of safety behaviors, and its application software is an essential tool for the research. Based on the QSIM algorithm and the related theories in the social field force, this study optimizes the filtering process of QSIM algorithm using the GA-BP algorithm (Genetic algorithm-BP neural network), and establishes a complete qualitative simulation system of group safety behaviors. In this study, a qualitative simulation software platform of group safety behaviors is designed and established. Moreover, the simulation results using different algorithm are analyzed and compared, and the statistical charts are plotted for displaying the development trend and evolution laws of group safety behaviors. According to the experimental qualitative simulation results on group safety behaviors of coal miners, the proposed qualitative simulation technology of group safety behaviors can improve efficiency and reliability of the qualitative simulation. The developed software platform can provide a convenient and effective qualitative simulation tool for further exploring the laws of group safety behaviors.