Smart Home Solutions Using Wi-Fi-based Hardware

Home automation technology has been increasingly important in our lives, since it offers numerous advantages, e.g., greater comfort, safety, security and energy efficiency. A smart home automation system usually includes a central computer with deployed home automation software and several distributed sensors and actuators. Wired connections between a central computer and sensor/actuator nodes are already well established, however, wireless solutions are an emerging trend. This work addresses smart home automation solutions that are based on wireless Wi-Fi network. Such solutions enable an upgrade of an existing house into a smart house without modifications of hardware installations. The article includes an overview of related works in this research field, and a case study of cost effective home automation solution that is based on open source home automation software and wireless, custom developed, Wi-Fi based hardware

Silazni DC-DC pretvarač bez izlaznog kondenzatora

Low-power switched-mode power supply converters are used in applications where size and efficiency are critical. The buck converter size can be reduced by elimination of the bulky filter capacitor. The filtering function of this capacitor can be replaced by an output current ripple compensation circuit. The compensating circuit is applied, based on inductor current measurement and linear amplifier. The proposed compensating algorithm is investigated theoretically by simulation, and verified experimentally.DC-DC pretvarači malih snaga se koriste u uredjajima gdje su važni dimenzije i učinkovitost. Dimenzije pretvarača se mogu smanjiti sa izostavljanjem filtarskog kondenzatora. Umjesto sa kondenzatorom se funkcija gladjenja izlaznog napona može izvesti sa kompenzacijom valovitosti struje zavojnice. Za kompenzaciju valovitosti struje je potrebno mjeriti trenutnu vrijednost struje induktora koja se preko obrade u linearnom pojačalu dodaje u protifazi struji zavojnice. Predloženi kompenzacijski postupak je istraživan teoretski te verificirani simulacijski i eksperimentalno

NONLINEAR CONTROL APPROACH FOR BUCK CONVERTER BY USING FIELD PROGRAMMABLE GATE ARRAY

V nalogi je predstavljena izvedba napetostne regulacije pretvornika navzdol z regulatorjem stanj podprtim s sistemom mehke logike. Regulacija je izvedena v programirljivem vezju FPGA (Fields Programmable Gate Array). Parametri regulatorja z mehko logiko se nastavljajo z genetskim algoritmom glede na želen dinamični odziv napetostno reguliranega pretvornika navzdol. Podan nelinearni pristop k regulaciji pretvornika navzdol je bil najprej preskušen na simulacijskem vezju, izdelanem v programskem paketu MATLAB/SIMULINK. Rezultati simulacij so potrdili, da se je s spremenljivo nastavitvijo ojačanj regulatorja stanj možno približati želenemu dinamičnemu odzivu napetostno reguliranega pretvornika navzdol, glede na fizikalne omejitve delovanja pretvornika ter zmožnosti regulatorja. Na osnovi dobljenih rezultatov iz simulacij je bilo izdelano eksperimentalno vezje, na katerem je bila preverjena nelinearna regulacija napetosti pretvornika navzdol. Regulator z ostalimi potrebnimi enotami za zajemanje digitalnih signalov iz analogno-digitalnega pretvornika ter generiranje pulznoširinskih signalov so izvedeni v programirljivem vezju FPGA. Celoten regulacijski algoritem se izračuna v 60ns, kar omogoča izvajanje v realnem času. Stikalna frekvenca napetostno reguliranega DC-DC pretvornika navzdol znaša 200KHz.The thesis presents the implementation of fuzzy control algorithm (state controller with adjustable gains by fuzzy sets) in DC-DC Buck converter. All tasks are implemented in FPGA (Fields Programmable Gate Array). To tune the fuzzy sets parameters according to predefined dynamic response of voltage controlled buck converter genetic algorithm is used. The nonlinear voltage control of buck converter was initially tested on a simulation circuit constructed in the MATLAB/SIMULINK software package. Simulation results proved that by introducing the variable gains in state controller, predefined dynamical responses could be reached within physical limitations of the system and limitation of the controller. Based on simulation results, an experimentally circuit was made, and used to test the buck converter nonlinear control. Digital controller with other units like A/D acquisition of digital signals and PWM unit were implemented by means of programmable FPGA circuit. With the calculation of whole control algorithm in 60 ns a real-time operation is archived. The switching frequency of buck-converter PWM unit is 200 kHz

A Survey on the State-of-the-Art and Future Trends of Multilevel Inverters in BEVs

All electric vehicles are the only way to decarbonize transport quickly and substantially. Although multilevel inverters have already been used in some transportation modes, they are rarely used in road transportation, especially in light-duty passenger BEVs. With the transition to a high 800-V DC link to extend the driving range and enable extreme fast charging, the possibility of using multilevel inverters in commercial light-duty passenger BEVs becomes feasible. Higher efficiency, higher power density, better waveform quality, lower switching frequency, the possibility of using low-rated switches, and inherent fault tolerance are known advantages of multilevel inverters that make them an efficient option for replacing 2-level inverters in high DC link passenger BEVs. This paper discusses high DC link voltage benefits in light-duty passenger BEVs, presents the state-of-the-art of different conventional multilevel inverter topologies used in BEVs, and compares them with conventional 2-level inverters from different aspects and limitations. Based on commercial upper-class passengers’ BEV data and a review of multilevel inverters on the market, future trends and possible research areas are identified

Control of a Modified Switched-Capacitor Boost Converter

Switched-capacitor converters and their alternatives have been shown to provide high efficiency with high power densities on smaller volumes, and can thereby be a suitable choice for energy harvesting. This paper proposes a hybrid power architecture based on a switched-capacitor topology and a boost converter that can be used for such purposes. A switching capacitor circuit can achieve any voltage ratio, allowing a boost converter to increase the input voltage to higher voltage levels. The first stage is unregulated with high-efficiency voltage conversion. The boost stage provides a regulated voltage output on such a converter. Rather than cascading two converters, their operation is integrated for the output voltage regulation. One major problem of switched-capacitor converters is output voltage regulation, which is solved by the interconnection of the power stages. The simplicity and robustness of the solution provide the possibility to achieve higher voltage ratios than cascading boost converters and provide higher efficiency. The converter’s size and cost can be improved with the integration of switching capacitors in DC-DC converter structures. A converter prototype has been designed, modelled, and built for the input voltage level of 2 V and power level of 5 W

Design and Implementation of ESP32-Based IoT Devices

The Internet of Things (IoT) has become a transformative technology with great potential in various sectors, including home automation, industrial control, environmental monitoring, agriculture, wearables, health monitoring, and others. The growing presence of IoT devices stimulates schools and academic institutions to integrate IoT into the educational process, since IoT skills are in demand in the labor market. This paper presents educational IoT tools and technologies that simplify the design, implementation, and testing of IoT applications. The article presents the introductory IoT course that students perform initially and then presents some of the projects that they develop and implement on their own later in the project

DC-Link Based Micro-grid System

Design and evaluation of dynamic model of multi-input/multi-output power converter consisting of six converters con-nected by dc-link will be presented in the paper. The model was created in Matlab/Simulink based on the existing sys-tem, with the goal of evaluating various power management strategies, where only transient behavior in case of changed operating regime is of interest. In future the model will be used as a Software-In-the-Loop development tool for the design of supervisory control algorithms