Series Arc Fault Breaker in Low Voltage Using Microcontroller Based on Fast Fourier Transform

Series Arc Fault is one of the disturbances of arcing jump is caused by gas ionization between two ends of damaged conductors or broken wire forming a gap in the insulator. Series arc fault is the primary driver of electrical fire. However, lack of knowledge of the disturbance of series arc fault causes the problem of electrical fire not be mitigated. Magnitude current is not capable to detect of series arc fault. Therefore, this paper proposes fast fourier transform (FFT) to detect series AC arc fault in low voltage using microcontroller ARM STM32F7NGH in real time. A cheap and high speed of microcontroller ARM STM32F7NGH can be used for FFT computation to transform signal in time domain to frequency domain. Moreover, in this paper, protection of series AC arc fault is proposed in the real time mode. In this experimental process, some various experiments are tested to evaluate the reliability of FFT and protection with various load starts from 1 A, 2 A, 3 A, 4 A in resistive load. The result of this experiment shows that series AC arc fault protection with STM32F7 microcontroller and FFT algorithm can be utilized to ensure series AC arc fault properly.

Design and Development of Non-Linearly Controlled Class-D Audio Amplifier

A systematic and simple approach to develop a 20 W audio frequency range switch mode amplifier is presented in this paper. A non-linear sliding mode (SM) technique-based low cost analog controller enables the realized amplifier to deliver highly linear and efficient operation throughout the audio frequency spectrum. The theoretical aspects and practical limitations in the design and realization of subsystems, such as the signal conditioning stage, power stage and sliding mode controller, are considered, while the viable solution is also stated and justified. The hardware realization scheme is also elaborated, based on which the laboratory prototype is fabricated. Hardware results with a 4 Ω resistive load are given on which the performance of the amplifier is evaluated. The total harmonic distortion (THD) below 1% and 73% efficiency at peak load make the amplifier well suited for high quality audio application.

Analisis Kinerja Metode Fuzzy Teroptimasi PSO untuk Strategi Kendali MPPT pada Sistem Solar Photovoltaic

A fuzzy control system has been widely used in various problem solving. Its performance can be optimized using particle swarm optimization (PSO). This performance can be proven by applying it to the maximum power point tracking (MPPT) control strategy on solar photovoltaic systems. Solar photovoltaic power generation systems are increasingly popular because they are clean and renewable energy sources. The power generated by solar photovoltaic is strongly influenced by solar irradiation and the load carried. In order to obtain maximum power output, an MPPT control strategy is needed. An MPPT control strategy based on fuzzy and PSO hybrid control systems is proposed in this research. The fuzzy-PSO method selects and produces the optimal duty cycle for the boost dc-dc converter in a solar photovoltaic system. Variable duty cycle due to solar irradiation and load changes can be conditioned by the fuzzy-PSO-based MPPT method to extract maximum power. The research results show that the fuzzy-PSO method can control the solar photovoltaic output voltage through a dc-dc converter to produce maximum power at various solar irradiations. Test result by applying a resistive load produces output power at the maximum point. The best result is obtained in the 100 Ohm load test: the response time of 0.0818 seconds and excellent robustness.

A Piezoelectric Wave Energy Harvester Using Plucking-Driven and Frequency Up-Conversion Mechanism

In this study, a plucking-driven piezoelectric wave energy harvester (PDPWEH) consisted of a buoy, a gear train frequency up-conversion mechanism, and an array of piezoelectric cantilever beams was developed. The gear train frequency up-conversion mechanism with compact components included a rack, three gears, and a geared cam provide less energy loss to improve electrical output. Six individual piezoelectric composite beams were plucked by geared cam to generate electrical power in the array of piezoelectric cantilever beams. A sol-gel method was used to create the piezoelectric composite beams. To investigate PDPWEH, a mathematical model based on the Euler–Bernoulli beam theory was derived. The developed PDPWEH was tested in a wave flume. The wave heights were set to 100 and 75 mm, the wave periods were set to 1.0, 1.5, and 2.0 s. The maximum output voltage of the measured value was 12.4 V. The maximum RMS voltage was 5.01 V, which was measured by connecting to an external 200 kΩ resistive load. The maximum average electrical power was 125.5 μw.

Compact High-Voltage AC Generator with Pulse Transformer for High-Frequency Irreversible Electroporation (H-FIRE)

This paper is focused on a design of a high-voltage (HV) generator, which is proposed for a high-frequency irreversible electroporation (H-FIRE). The generator produces bursts of bipolar symmetrical pulses. Most HV sources used for cell electroporation are based on a controlled discharge of a capacitor into a resistive load. This solution is very simple, but it is associated with a certain risk of an uncontrolled discharge of the capacitor. We present a different type of the generator, where a DC-AC inverter with pulse transformer is used and where the mentioned risk is eliminated. Our generator is able to deliver bursts with variable length from 50 to 150 μs and a gap between bursts can be set from 0.5 to 1.5 s. Pulse frequency can be varied from 65 to 470 kHz and the output voltage is controlled in two ranges from 0 to 1.3 kV or from 0 to 2.5 kV. Results are presented with resistive load and with tissue impedance load.

Control of the expiratory flow in a lung model and in healthy volunteers with an adjustable flow regulator: a combined bench and randomized crossover study

Background Pursed-lips breathing (PLB) is a technique to attenuate small airway collapse by regulating the expiratory flow. During mandatory ventilation, flow-controlled expiration (FLEX), which mimics the expiratory flow course of PLB utilizing a digital system for measurement and control, was shown to exert lung protective effects. However, PLB requires a patient’s participation and coordinated muscular effort and FLEX requires a complex technical setup. Here, we present an adjustable flow regulator to mimic PLB and FLEX, respectively, without the need of a patient’s participation, or a complex technical device. Methods Our study consisted of two parts: First, in a lung model which was ventilated with standard settings (tidal volume 500 ml, respiratory rate 12 min−1, positive end-expiratory pressure (PEEP) 5 cmH2O), the possible reduction of the maximal expiratory flow by utilizing the flow regulator was assessed. Second, with spontaneously breathing healthy volunteers, the short-term effects of medium and strong expiratory flow reduction on airway pressure, the change of end-expiratory lung volume (EELV), and breathing discomfort was investigated. Results In the lung model experiments, expiratory flow could be reduced from − 899 ± 9 ml·s−1 down to − 328 ± 25 ml·s−1. Thereby, inspiratory variables and PEEP were unaffected. In the volunteers, the maximal expiratory flow of − 574 ± 131 ml·s−1 under baseline conditions was reduced to − 395 ± 71 ml·s−1 for medium flow regulation and to − 266 ± 58 ml·s−1 for strong flow regulation, respectively (p < 0.001). Accordingly, mean airway pressure increased from 0.6 ± 0.1 cmH2O to 2.9 ± 0.4 cmH2O with medium flow regulation and to 5.4 ± 2.4 cmH2O with strong flow regulation, respectively (p < 0.001). The EELV increased from baseline by 31 ± 458 ml for medium flow regulation and 320 ± 681 ml for strong flow regulation (p = 0.033). The participants rated breathing with the flow regulator as moderately uncomfortable, but none rated breathing with the flow regulator as intolerable. Conclusions The flow regulator represents an adjustable device for application of a self-regulated expiratory resistive load, representing an alternative for PLB and FLEX. Future applications in spontaneously breathing patients and patients with mandatory ventilation alike may reveal potential benefits. Trial registration: DRKS00015296, registered on 20th August, 2018; URL: https://www.drks.de/drks_web/setLocale_EN.do.

A Novel Fundamental Frequency Switching Operation for Conventional VSI to Enable Single-Stage High-Gain Boost Inversion with ANN Tuned QWS Controller

Single-stage high-gain inverters have recently gained much research focus as interfaces for inherent low voltage DC sources such as fuel cells, storage batteries, and solar panels. Many impedance-assisted inverters with different input stage configurations have been presented. To decrease passive component sizes, these inverters operate at high-frequency switching. The high-frequency switching optimizes the passive component sizes but introduces many challenges in the form of high-frequency inductor design, control complexity, high-frequency gate driver requirements, high semiconductor losses, and electromagnetic interferences. This article proposes a novel fundamental frequency switching operation for the conventional voltage source inverters (VSI) to operate as a single-stage high-gain inverter. As the novel operational strategy changes the behavior of conventional VSI from buck inverter to a boost inverter, it is hereafter termed as a novel inverter. By virtue of the operation strategy, switches withstand peak inverse voltage (PIV) equal to DC link voltage, unlike other impedance assisted boost inverters where PIV across switches is the amplified DC voltage. The proposed inverter can invert low-level DC voltage to high voltage AC with low total harmonic distortion (THD) in a single stage without the help of any external filter. A novel quarter-wave symmetric phase-shift controller is proposed for variable voltage and frequency control of proposed inverters tuned by a back-propagation thin-plate-spline neural network (BPTPSNN). Mathematical analysis with experimental validation is presented. Experimentation is carried out on a prototype of 2 kW for single-phase resistive load, induction motor, and non-linear loads.

Concentrator Photovoltaic System (CPV): Maximum Power Point Techniques (MPPT) Design and Performance

The research carried out in this work aimed to study the performance of MPPT techniques applied to the Concentrator Photovoltaic (CPV) System for the research and the pursuit of the Maximum Power Point (MPP).This study presents a modeling and simulation of the CPV system. It consists of a PV module located in the focal area of a parabolic concentrator, a DC / DC converter (Boost), two MPPT controls (P&O and FL) and a resistive load. This chapter presents the two MPPT techniques (P&O and FL) performances. The obtained results show the importance of cooling systems integration with CPV system. This hybrid system design results in good MPPT P&O and FL performance. The numerical results obtained with Matlab/Simulink® software have generally shown that the two MPPT controls result in better performance in terms of speed, and accuracy, stability. In fact they showed that the CPV system is stable.

The influence of the initial reinforcement value on physiological parameters of conditioned respiratory reflex

BACKGROUND: Most of the studies of the role of reinforcement in the formation of adaptive behavior were performed on animals. At the same time, such an experimental model as a conditioned respiratory reflex to resistive load, has not been sufficiently studied, although an unconditioned reflex to additional resistance to breathing, on the basis of which a conditioned one is formed, is a stable reaction that has clear quantitative evaluation criteria, and the conditioned reflex itself is relatively strong, easily normalized, reluctantly extinguished and does not require observance of a number of methodological conditions. AIM: To study the influence of the initial value of reinforcement on the physiological parameters of the conditioned respiratory reflex. MATERIALS AND METHODS: The work was carried out on people of both genders, 16 people, aged 18 to 44, practically healthy. The unconditioned stimulus was applied in four gradations of external respiratory resistance: 11; 28; 54; 76 cm water • l/sec. The conditioned reflex was formed by the classic type, the duration of application of the conditioned stimulus was not fixed and its end coincided with the end of the action of the unconditioned stimulus, the period of the isolated action of the conditioned signal was 10 sec. As physiological parameters, we studied the ventilatory and motor parameters of respiration, the temporal parameters of the conditioned reaction. RESULTS: The influence of the unconditioned stimulus on the value of the tidal volume after the combination in all subjects depended on the absolute reinforcement values used in this combination, and was weakly connected with the initial reinforcement value. The influence of the external resistance on breathing used in this combination was significantly higher on such parameters as intraoral pressure of inspiration and expiration; the role of the initial reinforcement value in the dynamics of the given parameters was not confirmed. CONCLUSIONS: Most “sensitive” to the action of the initial value of the resistive load were the temporal parameters of the conditioned respiratory reflex — the latent period and the time of the conditioned reaction; the parameters of the “ventilatory” and “motor” outputs of the external respiration system changed noticeably, the spirometric parameters showed very little dynamics, and the capnographic parameters practically did not change. The dynamics of the parameters of the conditioned respiratory reflex to increased external respiratory resistance permits to single out groups of signs that have the greatest semantic significance for evaluation of the system-forming and discriminating role of the initial gradation of the reinforcement factor.

Experimental Analysis of Modified DC-P&O Technique with Arm Controller for a Stand-Alone 40 W PV System

The world is moving towards the generation of electricity with renewable energy sources (RES) due to the deterioration of the green environment and trying to replace non-renewable energy resources. The real-time results are achieved with the help of an arm controller, having good controller efficiency with the Waijung toolbox, compatible with MATLAB using STM32ST-link utility. In this paper, the authors are focused on areas such as easy to implement controller efficiency, and real-time solutions for modified direct-control perturbation & observation (DC-P&O) technique based on 32- bit ARM Cortex microcontroller (STM32F407VGT6) with embedded programming using Waijung blocksets, which offers very expected outcomes of the problem to make the stand-alone system efficient with fast-tracking. The observation setup is tested with a 40-watt photovoltaic (PV) panel with resistive load for achieving its stability. The designed algorithm enhances the efficiency of the controller by 84.48% for the real-time parameters of the PV panel at maximum power point (MPP) for a 57% duty ratio.