Part Of Power Supply System Research Articles

Synthesis of an automatic control system for a voltage inverter as part of an autonomous power supply system with a hydrogen module

This paper examines the problem of synthesizing a two-loop control system for a three-phase voltage source inverter designed for an autonomous power supply system. This type of DC/AC converters is an essential part of power supply systems with renewable energy sources as primary sources, and, accordingly, must corresponds to the requirements for the electric power quality. These requirements are met through circuit design solutions, as well as through the construction of high-precision automatic control systems. The system integrates: a hydrogen electrolyzer, a hydrogen storage system, and a hydrogen fuel cell. The paper proposes a method for calculating the parameters of PI controllers with resonant components, based on the time-scale separation method and allowing independent adjustment of the controller components. The introduction of a resonant component ensures high tracking accuracy for a desired main voltage harmonic and selective suppression of external harmonic influences. The proposed approach allows to synthesize an automatic control system that significantly improves the quality of the voltage inverter output parameters.

Энергоэффективный конденсаторный DC-DC преобразователь для автономной системы электроснабжения

The main requirement for autonomous power supply systems is improved weight-size and energy parameters. A promising way to solve this problem is to use DC-DC converters based on resonant structures with switched capacitors. Improvement of energy indicators of the converter is achieved due to soft-switching mode of semiconductor elements providing reduction of dynamic power losses and increasing the level of the primary source. Improvement of weight-size parameters of the converter is provided due to the following: multi-cycle principle of the design providing a significant increase of frequency conversion up to several hundred kHz due to multiple reduction of installed capacity of semiconductor elements; high specific energy indicators of modern multilayer ceramic capacitors, more than two orders of magnitude higher than similar indicators of reactors and transformers; optimization of parameters of semiconductor and reactive elements, which also contributes to significant reduction of weight and volume of power supply systems. The authors have conducted the analysis of weight-size parameters of the step-up DC-DC converter and the value of its efficiency under the assumption of proportionality of weight and volume of reactive converter elements to the maximum accumulated energy and proportionality of weight and volume of semiconductor elements to their installed capacity. The authors have proposed and studied the circuit of multipolar DC-DC converter based on structures with switched capacitors, which has the space symmetry. The space symmetry provides a significant improvement of weight-size parameters due to two-fold reduction of the total installed capacity of semiconductor elements. The volume and energy indicators of the converter under study as a part of power supply system have been evaluated. A method to design a power circuit of a capacitor converter with improved energy and weight-size parameters as a part of an autonomous power supply system is proposed. The authors have established the most effective ways to improve the weight-size and energy indicators of DC voltage converters. The improvement of weight-size parameters is achieved due to a twofold reduction of the installed capacity of semiconductor elements and optimization of the parameters of reactive elements. Improvement of energy indicators is achieved due to increasing the input voltage level of the converter and soft switching of its semiconductor elements.

Optimizing Layout of Distributed Generation Sources of Power Supply System of Agricultural Object

The increasing penetration of photovoltaic technology calls for the development of an effective method for optimization of grid-connected photovoltaic power plants. Although extensive studies on the definition, implementation, and optimization of these systems have been conducted, the design and management of a smart energy system remains a critical challenge. The purpose of the work is to increase efficiency of power supply system of agricultural facility by optimizing the placement and selection of parameters of photovoltaic sources of distributed generation. Application of photovoltaic sources of distributed generation as part of power supply system of agricultural enterprise allows to reduce the total consumption from the network in average basing on solar intensity data for 22 years by 40-53% from April to October, which is most expedient in view of the fact that this is a period of intensive work of the enterprise and the greatest load on its consumers; by 24-30% in February, March, and October; and by 14-17% the rest of the time.

Connection and operation of wind farms as part of electric power-supply systems through the example of Kaliningrad region

The issues of connecting wind power plants (WPP) to the power-supply system and their joint operation are currently gaining relevance due to the growth of their capacities and an abruptly variable pattern of its delivery to the grid. The paper presents the analysis of standards, recommendations and regulations related to connection and operation of WPPs as part of the power-supply system. The developed mathematical model of the Ushakovskaya WPP is used to analyze its main operating modes. Practical recommendations for changing the scheme of power generation of the plant at increased capacity are given with due regard to the standard requirements.

LiDAR Point Cloud Recognition and Visualization with Deep Learning for Overhead Contact Inspection.

As overhead contact (OC) is an essential part of power supply systems in high-speed railways, it is necessary to regularly inspect and repair abnormal OC components. Relative to manual inspection, applying LiDAR (light detection and ranging) to OC inspection can improve efficiency, accuracy, and safety, but it faces challenges to efficiently and effectively segment LiDAR point cloud data and identify catenary components. Recent deep learning-based recognition methods are rarely employed to recognize OC components, because they have high computational complexity, while their accuracy needs to be improved. To track these problems, we first propose a lightweight model, RobotNet, with depthwise and pointwise convolutions and an attention module to recognize the point cloud. Second, we optimize RobotNet to accelerate its recognition speed on embedded devices using an existing compilation tool. Third, we design software to facilitate the visualization of point cloud data. Our software can not only display a large amount of point cloud data, but also visualize the details of OC components. Extensive experiments demonstrate that RobotNet recognizes OC components more accurately and efficiently than others. The inference speed of the optimized RobotNet increases by an order of magnitude. RobotNet has lower computational complexity than other studies. The visualization results also show that our recognition method is effective.

Model of a Photovoltaic Cell for the MatLab/Simulink SimPowerSystems Library

A new Simulink model of a photovoltaic cell has been proposed. The model is focused on the use of a standard SimPowerSystems library with power engineering elements from the MatLab/Simulink software package. The model allows altering the values of solar irradiance, photovoltaic cell temperature and load resistance. The results of the model application are the calculated values of voltages and currents at the photovoltaic cell output. The Simulink model that has been developed implements the known dependence of the photovoltaic cell volt-ampere characteristic by using both standard MatLab/Simulink blocks and special electric SimPowerSystems library blocks. The model is characterized by the fact that the series and parallel resistance of the photovoltaic cell are made in the form of resistors from the SimPowerSystems library. The main calculation algorithm is implemented programmatically by using the “C” programming language. To increase the algorithm stability to algebraic cycles the restrictions parameters are introduced. A new technique of calculating the photovoltaic cell model parameters based on experimental data has been proposed. The technique includes the preparation of a system of equations with experimental values of the photovoltaic cell voltages and currents. Experimental tests have been carried out for the photovoltaic module OSP XTP 250 under different solar irradiance values. The tests showed that the relative error of the Simulink model that has been developed does not exceed 12 %. The Simulink model makes it possible to build photovoltaic modules and then to build schemes of photovoltaic power plants as a part of power supply systems. Due to the latter it is possible to simulate the electricity consumers’ work, weather conditions, and the presence of shadows or pollution on the surface of photovoltaic modules. Also, one can carry out a simulation of increasing failures in power plant photovoltaic modules, e.g. simulating of modules efficiency reducing because of their degradation, or simulating of modules series resistance increasing because of the photovoltaic cell internal contacts deterioration. The Simulink model that has been developed can be used both at the design stage and at the stage of photoelectric power plants operation.

Numerical computation for the impact of pantograph angles on the near-field and far-field aerodynamic noises of pantographs

Pantographs are an important part of power supply systems of high-speed trains, whose good working performance is a guarantee for the steady power supply and safety operation of high-speed trains. The aerodynamic drag of pantographs will have negative impacts on the running of high-speed trains. In the meanwhile, the disturbance effect of pantographs on airflow will cause large aerodynamic noises when a high-speed train runs at a high speed. Therefore, this paper conducted a numerical simulation for the flow field and aerodynamic noises of pantographs on the symmetrical plane, compared simulation results with experimental one, verified the correctness of the numerical simulation model, and further studied the impact of pantograph angles on radiation noises. When pantographs were working, cylindrical rods which were vertical to the direction of airflows had a more obvious disturbance effect on airflows and caused a larger range of vortex shedding. Shedding vortexes were mainly distributed at the pantograph head, hinge joints between upper and lower arms, and rear bases. Near-field aerodynamic noises on the longitudinal symmetrical plane of pantographs were distributed at the lower arm, middle hinge joints and bases. The maximum appeared at the middle hinge joints. The intensity of vortexes at the middle hinge joints, lower arms and bases when the pantograph angle was 60° was more than that at other pantograph angles. In this case, the near-field aerodynamic noise of pantographs was more than that of other pantograph angles. In addition, radiation noises of observation points of pantographs in all directions presented an obvious linear relationship. The far-field radiation noise of pantographs was gradually decreased with the increased distance from pantographs. In addition, the far-field radiation noises of pantographs on the same vertical plane had the intensity with the same level.