Microgrid energy management system for smart home using multi-agent system

This paper proposes a multi-agent system for energy management in a microgrid for smart home applications, the microgrid comprises a photovoltaic source, battery energy storage, electrical loads, and an energy management system (EMS) based on smart agents. The microgrid can be connected to the grid or operating in island mode. All distributed sources are implemented using MATLAB/Simulink to simulate a dynamic model of each electrical component. The agent proposed can interact with each other to find the best strategy for energy management using the java agent development framework (JADE) simulator. Furthermore, the proposed agent framework is also validated through a different case study, the efficiency of the proposed approach to schedule local resources and energy management for microgrid is analyzed. The simulation results verify the efficacy of the proposed approach using Simulink/JADE co-simulation.

Assessing Feature Importance for Short-Term Prediction of Electricity Demand in Medium-Voltage Loads

The design of new monitoring systems for intelligent distribution networks often requires both real-time measurements and pseudomeasurements to be processed. The former are obtained from smart meters, phasor measurement units and smart electronic devices, whereas the latter are predicted using appropriate algorithms—with the typical objective of forecasting the behaviour of power loads and generators. However, depending on the technique used for data encoding, the attempt at making predictions over a period of several days may trigger problems related to the high number of features. To contrast this issue, feature importance analysis becomes a tool of primary importance. This article is aimed at illustrating a technique devised to investigate the importance of features on data deemed relevant for predicting the next hour demand of aggregated, medium-voltage electrical loads. The same technique allows us to inspect the hidden layers of multilayer perceptrons entrusted with making the predictions, since, ultimately, the content of any hidden layer can be seen as an alternative encoding of the input data. The possibility of inspecting hidden layers can give wide support to researchers in a number of relevant tasks, including the appraisal of the generalisation capability reached by a multilayer perceptron and the identification of neurons not relevant for the prediction task.

Concurrent vibration attenuation and low-power electricity generation in a locally resonant metastructure

We investigate piezoelectric energy harvesting on a locally resonant metamaterial beam for concurrent power generation and bandgap formation. The mechanical resonators (small beam attachments on the main beam structure) have piezoelectric elements which are connected to electrical loads to quantify their electrical output in the locally resonant bandgap neighborhood. Electromechanical model simulations are followed by detailed experiments on a beam setup with nine resonators. The main beam is excited by an electrodynamic shaker from its base over the frequency range of0–150 Hz and the motion at the tip is measured using a laser Doppler vibrometer to extract its transmissibility frequency response. The formation of a locally resonant bandgap is confirmed and a resistor sweep is performed for the energy harvesters to capture the optimal power conditions. Individual power outputs of the harvester resonators are compared in terms of their percentage contribution to the total power output. Numerical and experimental analysis shows that, inside the locally resonant bandgap, most of the vibrational energy (and hence harvested energy) is localized near the excited base of the beam, and the majority of the total harvested power is extracted by the first few resonators.

A Functional Electrical Stimulator to Enable Grasping Through Wrist Flexion

Functional electrical stimulation is an assistive technique that utilizes electrical discharges to produce functional movements in patients suffering from neurological impairments. In this work, a biphasic, programmable current- controlled functional electrical stimulator system is designed to enable hand grasping facilitated by wrist flexion. The developed system utilizes an operational amplifier based current source and is supported by a user interface to adjust stimulation parameters. The device is integrated with an accelerometer to measure the degree of stimulated movement. The system is validated, firstly, on two passive electrical loads and subsequently on four healthy volunteers. The device is designed to deliver currents between 0-30mA, and the error between the measured current and simulated current for two loads were -0.967±0.676mA and -0.995±0.97mA. The angular data from the accelerometer provided information regarding variations in movement between the subjects. The architecture of the proposed system is such that it can, in principle, automatically adjust the parameters of simulation to induce the desired movement optimally by measuring a stimulated movement artifact (e.g., angular position) in real time.

Energy Management Strategy for an Autonomous Hybrid Power Plant Destined to Supply Controllable Loads

This paper proposes an energy management strategy (EMS) for a hybrid stand-alone plant destined to supply controllable loads. The plant is composed of photovoltaic panels (PV), a wind turbine, a diesel generator, and a battery bank. The set of the power sources supplies controllable electrical loads. The proposed EMS aims to ensure the power supply of the loads by providing the required electrical power. Moreover, the EMS ensures the maximum use of the power generated by the renewable sources and therefore minimizes the use of the genset, and it ensures that the batteries bank operates into the prefixed values of state of charge to ensure their safe operation. The EMS provides the switching control of the switches that link the plant components and decides on the loads’ operation. The simulation of the system using measured climatic data of Mostoles (Madrid, Spain) shows that the proposed EMS fulfills the designed objectives.

SIMULATION OF THE CONTROL PROCESS ELECTRIC LOADS IN THE DISTRIBUTION NETWORK OF 0.4 KV

В статье рассматривается решение задачи моделирования процесса управления электрическими нагрузками для повышения качественных показателей электрической энергии в распределительных электрических сетях 0,4 кВ на основе использования адаптивной системы управления электрическими нагрузками. Проведен анализ существующих методов снижения неравномерности распределения мощностей. Алгоритм процесса управления электрическими нагрузками в распределительных электрических сетях, алгоритмы анализа распределения мощностей и напряжений по фазам сети, а также алгоритм устранения отклонений напряжения, которые могут быть использованы при разработке электрооборудования. для обеспечения необходимого качества электроэнергии. The paper considers the solution of the problem of modeling the process of controlling electrical loads to improve the quality parameters of electrical energy in distribution electrical networks of 0.4 kV based on the use of an adaptive system for controlling electrical loads. The analysis of existing methods of reducing the uneven distribution of capacities is carried out. An algorithm for the process of controlling electrical loads in distribution electrical networks, algorithms for analyzing the distribution of powers and voltages over the phases of the network, as well as an algorithm for eliminating voltage deviations, which can be used in the development of electrical equipment to ensure the required quality of electricity, have been developed.

Aircraft Electric Machines

Current trend in aviation is to increase efficiency of all the aircraft’s systems. This leads to a reduction of fuel consumption which has also positive effect on emissions. One possibility how to reach this aim is to replace hydraulic and pneumatic system with an electrical power system. Because many on-board electrical loads are in the form of electrical drives, the special attention is given to electric motors and their electronic speed controllers / power converters. Furthermore, electric motors suitable for traction/propulsion are presented. Moreover, the various types of starter/generators suitable for on-board utilisation are compared in the paper.

A Novel Fully Controllable Rotary Switch for Electrical Installation in Buildings

In an electrical installation in buildings, electromechanical switches are mostly used to turn on and off a load. However, sometimes there are two or more switches in the same circuit intended to control the same load. Thus, a conflict can happen between multi-users who are trying to overtake the control of the load (such as turning it on or off). To solve the problem, this paper proposes a novel switch called “Fully Controllable Rotary Switch” (FCRS) in which it can fully control not only the load but also other switches by blocking them or giving them limited or full access over the electrical circuit and the loads. For validation purposes, the utilization of FCRS in buildings is compared to the traditional switches under the same functionality and conditions. Results show that FCRS has the ability to control many electrical loads simultaneously, control other switches in the circuit, increase the satisfaction, security, and privacy of the users. Finally, it reduces the conflict between multi-users and the investment cost by avoiding installing additional switches and protection devices.

Experimental Determination of Parameters of Nonlinear Electrical Load

The paper deals with issues of modeling nonlinear electrical loads of various types, such an uncontrolled rectifier, thyristor rectifier, thyristor power regulator and mixed equivalent nonlinear load. For these load types, existing analytical expressions were identified to determine the magnitudes of harmonic currents, and waveforms of currents were obtained during measurements in laboratory conditions with variable parameters of the grid impedance and load. The obtained results were compared, and it was found that the error in determining the magnitudes of harmonic currents can reach 60% for an individual load and 54% for an equivalent load. A more accurate method for determining the parameters of nonlinear electrical load is also proposed, which is based on the application of shunt harmonic filters. In laboratory conditions, it was found that when using the developed method, the error did not exceed 10% for an individual load and 14% for an equivalent load.