ABSTRACT. In this paper the short overview of harmonic load models of some electric nonlinear low voltage devices is presented. Differently from the majority of the references based on aggregate models, this paper deals with the literature related to load models of the individual low voltage electric devices. The paper specifies advantages and disadvantages of the models, their applications, as well as future applications and need for new model development.

ABSTRACT. An algorithm for calculating savings in electrical energy costs for industrial customers, using photovoltaic battery system and determination of dimensions of that system are presented in this paper. Photovoltaic battery system was applied within demand side management (DSM) program for shaving power peak. Algorithm was tested by real daily diagram of demand (one of industrial customers in Serbia) and its results were presented.

ABSTRACT. This paper considers one part of the islanded microgrid design - the optimization of energy storage capacity. GridLab-D open source simulation tool is used to for simulation of microgrid elements. Matlab environment is used to run an optimization solver. The product GridMat is used as an interface tool between Matlab and GridLab-D. Eight different scenarios are tested. For each of them an economic scheduling optimization problem on the considered microgrid is formulated and solved by means of three optimizations methods. The obtained results are discussed and some conclusions are drawn.

ABSTRACT. This paper analyzes the most prominent smart grid functions from the Internet of Things implementation perspective. A Smart MV/LV substation is proposed as a solution that will handle intelligent operations, such as real-time monitoring, control, and system management, in a successful manner. However, these great benefits come at a price. With rapidly-evolving IoT network, maintaining cyber privacy and security will present a great challenge in the future and solutions to efficiently overcome these weaknesses should be further investigated and developed.

ABSTRACT. The review of relations for determining self and mutual cable impedances is given in the paper. Afterwards, the accuracy of presented relations is tested. The problem of one-wire cables with electrical protection grounded on one or both ends is especially discussed.

ABSTRACT. Since many years up to date now ,most of researchers demonstrate the development of the vacuum interrupters by using of a refractory materials “ Alloys” for sustainable against of an arcing currents and both of chopping currents and transient over voltages . The conventional designing switches are still constructing in the same classical steps of a toggle ways, thus have been dominated yet. This paper presents the sequence of the switching process time for a static switching process for application of medium voltage switching technique. Since DESY & Behlke Power Electronics and LLC are designed for RF systems, basically depending on Crow-bar and snubber circuit for protection applications .

ABSTRACT. Parameters of a vacuum interrupter are essential. Although most of researchers and industries are involving only by using a refractory materials “alloys” electroplates for vacuum interrupter for the sake of sustainable materials against both arcing current, chopping currents and disruptive over voltages , but the direction of create the parameters for medium voltage switches are very necessary .For offering the new concepts of what happens inside vacuum switch itself which creates a homogenous switching process within a semiconductors switches for promising future technology .

This paper addresses the description of all parameters and evaluates switching processing times for three circuit breakers , VD4 /ABB Vacuum type 6.6KV/1500A/20KV/40KV-IEC60-071 for maximum switching times 2.7ms .Three synchronous generators 6.6KV/8MW each have been connected to three power transformers, rating 6.6KV/1250KVA in refinery power plant.

ABSTRACT. The Proportional Integral (PI) controller is the most common part of a control algorithm for electric drives. It gives an acceptable and satisfactory results in the wide range of the electrical drive applications and therefore represents an important part of the teaching process in the engineering sciences. Integrated Education Platform for controllers tuning using graphic user interface in dSPACE ControlDesk environment. Analytical Magnitude Optimum Criterion is used for controllers tuning in the case of the Rotor Field Oriented (RFO) control algorithm. This platform is implemented with dSPACE DS1103 control board and evaluated through laboratory experiments.

ABSTRACT. Designing an affordable virtual laboratory for control system stability simulation and remote experimentation with variable speed drives is the focus of this paper. Centre of the laboratory is Raspberry Pi that serves the purpose of web server, Modbus master and communicates with Arduino Due which is used for data acquisition through various affordable sensors.

ABSTRACT. The article presents some of the main types of modulations of low and higher order. Modulations are a very important part of any telecommunications system. Simulations are made using MATLAB software. They can be used for educational purposes in engineering education.

ABSTRACT. This article is presented the design and implementation of a laboratory model of the panel automatic start of reserve (AVR). The model manages switching switches from primary to backup power

ABSTRACT. This article presents a web base teaching laboratory for the production of green energy, equipped with meteorological system. The laboratory site is created with the ability to receive and display information in real time not only to weather characteristics and generated electricity but also saved emissions of greenhouse gases.

ABSTRACT. This paper presents an approach for studying the spectrum analysis of analog signals with various shape forms, by using trigonometric and complex forms of Fourier transformation. An algorithm and its implementation in MATLAB environment have been developed. The implemented software allows studying the spectrum of different analog signals and the influence of signals parameters on its spectrum. The presented approach can be used in engineering education for studying this process.

ABSTRACT. This paper presents an approach for studying the spectrum analysis of discrete signals with different shape forms, by using Discrete Fourier transformation and Fast Fourier transformation. An algorithm and its implementation in MATLAB environment have been proposed. So by using implemented program code the influence of signals parameters on their spectrum can be deep analyzed. The paper can be used in engineering education for studying this process.

ABSTRACT. The purpose of this article is to review the state-of-play of the verification, assessment and authorization processes and procedures for the railway structural subsystems Contro-command and Signalling-CCS (ERTMS) in Bulgaria. Based on a study, the most important issues and discrepancies are highlighted, discussed and provided as outcomes of this review.

ABSTRACT. The article is dedicated to the search for a solution to the problems associated with the "human factor", topical in the complex control systems. The necessity of the creation of complex models that reflect the behavior of the operator in the automatic control systems is substantiated. Functions of man are structured depending on the used by him mechanisms of representation and processing of the information.

ABSTRACT. An algorithm for operational control of data obtained in the process of cutting is presented. It is realized using Ladder application software in order to achieve automated control of technological parameters via programmable logic controller. As the system allows real time monitoring and evaluation of current and preliminary determined control values it is provisioned to show the working mode and to signalize in critical cases.

ABSTRACT. For unmanned aerial systems (UAS) to be successfully deployed and integrated into the national airspace, it is imperative that they possess the capability to effectively complete their missions without compromising the safety of other aircraft, as well as people and property on the ground. This necessity creates a natural requirement for UAS that can respond to uncertain environmental conditions and emergent failures in real-time, with robustness and resilience close enough to those of manned systems. This report introduces a system that meets this requirement with the design of a real-time onboard system for flight control and technical condition capability to continuously monitor sensors, software and hardware components. This system can detect and diagnose failures and violations of safety or performance rules during the flight of a UAS.

ABSTRACT. The current paper discusses the design and the functionality of the integrated navigation and 9DoF inertial system based on MEMS sensors which is capable to run independently the GNSS system and inertial system to solve the navigation problems. The both system may also run simultaneously and form the integrated navigation system based on Extended Kalman filter (EKF). All systems and devices are connected to the microcontroller by independent interfaces which allows parallel read and write using interrupts which allows operating at very high speed (10Hz for GPS receiver and 200Hz for IMU system) to decrease significantly the inertial system errors.

ABSTRACT. This paper presents a method for conducting an experiment with controllable object to acquire data, through which is achieved the identification of the high order linear models. The experiment is conducted in the closed loop with a controller. Frequency characteristics are used for obtaining the parameters of the model, i. e. the critical operating mode values.

ABSTRACT. This paper aims to explore the theories and techniques behind procedures of wireless controller system for mini CNC milling machine. The developed controller enables the machine tool to be controlled based on wireless communication and NC data generated from CAD/CAM systems. Then, a computer vision component using a web camera is proposed for the NC machine tool monitoring. It is explained the position on the machining table. The research consists of two parts. The first part deals with the mini CNC machine. This part is mainly composed of mechanical frame and DC motor for machine tool. In the second part, a new component that called “wireless controller system” is introduced. Designing “wireless controller system” will allow us to automatically modify NC codes according to the sizes of workpiece received from CAD/CAM system. This newly designed wireless controller system can be widely used in electrical and medical industry for making small parts and engraving small features. Confirmation case study was tested during the design stage. Different commercial products were carefully selected and purchased from the market. Raspberry Pi was used as the motion controller. Different setup and configuration issues using Raspberry Pi were explored. A newly motion controller using Arduino Uno and TB6560AHQ was also tested and implemented as a replacement of regular motion controller to reduce cost. Fabricated prototype wireless controller system was calibrated and tested under various self-testing procedures to meet industrial standard. Comprehensive cost analysis and profit estimation was conducted after completion of the prototype.

ABSTRACT. A Methodology plan for parallel Power generation units are essential. Many industrial plants are suffering from a repeating of shut downs for intertie between a self-power as a generators , and the national Grid specifically with type of 6.6KV when connected with the national grid rating of 33KV/6.6KV because of a nonhomogeneous of transformers CTs and VTs and a load shedding system. Azzawayia Refining Company (ARC) have many experiences of black out because of the tie-connection unit with national grid and the existing oil circuit breakers 6.6KV ES-1 switch board connecting with 33KV/6.6KV national grid . Moreover the instrument protection system is not reliable for a full operating works.

This paper focuses on the understanding of switching surge phenomena relatively with circuit breakers, including the necessary of parallel operating methods and synchronizing both CTs & VTs for steady stream power flows between tie systems for full operation loads.

ABSTRACT. In the present paper presents two types of artificial neural networks adapted to recognize the multicomponent tea mixed with fruit ingredients. The experimental study is based on VIS/NIR spectroscopy, measurement of color and pH. Principal components analysis (PCA) is use to reduced high dimensional feature space to three specific factors. The results of neural networks: Backpropagation Artificial Neural Network (BP-ANN) and Kohonen's Self-organizing map (SOM) shows recognize the analyzed samples with an accuracy of 99.4% and 98%, respectively.

ABSTRACT. An integrated two-phase interleaved dc-dc converter designed on CMOS 0.35 µm process, is proposed in this paper. Switching-mode amplifiers deliver large amount of energy to the transmitter’s power amplifier (PA) in the fourth generation (4G) long term evolution (LTE) wireless communication standard. The received results proved that tracking speed can be increased if two-phase switching-mode amplifier is used instead of single phase architecture. The simulation results show proper work of the designed circuit after layout design. The simulated efficiency of the converter is about 73% at particular case of 60 mA load current.

ABSTRACT. In this paper the efficiency of BUCK DC-DC converter with Zero Voltage Switching (ZVS) is an object of investigation. A simulation scheme of Gate Driver with Adaptive Dead Time (ADT) is proposed, which provides the independence of ZVS from the current value at which the transistors are switched. The influence on the switching losses of an externally connected drain-source capacitor is simulated using PSpice. Macros in the graphical analyzer Probe are proposed for calculating the average value of the currents, the losses in transistors and the efficiency. The simulation results are presented graphically as a function of the junction temperature.

ABSTRACT. In this paper a scheme of bidirectional integrating converter with frequency deviation is developed, featured by low power supply voltages and low power consumption. The scheme works on the method of a right ramp conversion. A mathematical and simulation model of the converter is created. The practical implementation proves the performance and functionality of the scheme, which is generally designed for measuring forces and torques in different technological processes. The results are presented in table and graphic form and corresponding conclusions are made.

ABSTRACT. The following paper considers a bidirectional series resonant DC-DC converter operating above the resonant frequency. The disadvantages of the classical implementation are discussed. A control method for the converter is proposed providing control characteristics improvement and increase of the efficiency. On the base of existing theoretical analysis, optimized characteristics are obtained demonstrating the improvements of the proposed converter.

ABSTRACT. In this paper the design of a half-bridge (HB) LLC resonant converter is presented. The operating principles are briefly explained, including the functional block diagram. The prototype has been built and experimental results are presented to support the theoretical analysis and to demonstrate the converter performance.

ABSTRACT. An optimal trajectory control system (CS) of series resonant converter (SRC) operating at constant frequency above the resonant one is proposed. CS is designed on the base of state-plane analysis of SRC and is realized on the principle of the Analog Behavioral Modeling, set in the OrCAD PSpice simulator. The aim is to determine the time intervals in the commutation process when the oscillating circuit voltage and current alter according to an optimal trajectory. This approach gives the opportunity to obtain minimum response time at guaranteed stable converter operation.

ABSTRACT. This paper gives an overview of high frequency power supply with constant output power, so called converters with energy dosing (CED). A characteristic feature of the CED is the fact that, by their operation principle, they provide energy dosing in the load. The output voltage obtained on that basis corresponds to the particular load parameters, the power always being equal to the specified value.Some converters are presented together with their modifications. The new advancements of CED and their design are also discussed in this paper. For most of the ideas, schemes, design and mathematical interpretation of electromagnetic processes there are author claims.

ABSTRACT. A short survey on the main features and parameters of wireless interfaces is presented in the present paper, in relation to their application in the modern embedded systems. They are more and more widely used to connect the increasing number of “intelligent”, programmable peripherals - sensors, actuators, etc., allowing not only reducing the number of the wires, but also distance monitoring and control of the object.

ABSTRACT. The subject of this article is the development and the testing of a wireless battery voltage monitoring system. A smart device using Wi-Fi interface is developed to measure the voltage and temperature of each cell of a battery. This device makes possible the construction of a smart battery monitoring system for control and optimization of the charge/discharge cycles of a battery.

ABSTRACT. ZigBee is one of the main standards for low-data-rate, short-range communications used in wireless sensor networks. The main advantages of this standard are mesh networking, low-power, low-complexity, reliability and operation on unlicensed frequency band, available Worldwide. In this paper is presented an approach to develop low-cost sensor nodes using an open-source hardware and software platforms, such as Arduino.

ABSTRACT. This paper presents a cost-effective angular position encoder linearization system based on a PIC18F2550 microcontroller. The linearization system is developed and employed to increase the encoder resolution and accuracy. More specifically, the encoder resolution is increased by three bits, while the maximal absolute measurement error is reduced by ten times.

ABSTRACT. This paper presents application of odometry model for position determination of mobile robot with differential drive with tracks. Sources of systematic errors for this type of robot drive are identified, analyzed and corrected. For practical analysis Lego Midndstorms robot was used. Presented experimental results shows consistent improvement of odometry localization accuracy at least for one degree.

ABSTRACT. In recent years,with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased,people began to use the method of recycling to waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method,comparative analysis through the case, get the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.