In this article, a new discrete-time control strategy for three-phase three-wire shunt active power filters (APFs) is presented, based on a mathematical model in the stationary reference frame. It ...involves a feedback-linearization-type approach to control the filter currents, whereby the voltage control loop is decoupled from the current control. The voltage control loop is for controlling the dc-side voltage of the pulsewidth modulation (PWM) converter, and employs a proportional-integral (PI) controller to generate the reference amplitude for the compensated grid currents. An important feature of the proposed control strategy is the compensation of the one-sampling-period delay caused by microcontroller computation using a finite impulse response (FIR) predictor. This predictor is designed to accomplish one-step-ahead prediction of the control variable, which is the PWM converter's switching function space vector. Furthermore, the FIR predictor is optimized so that the low-order harmonics in the control variable are predicted with minimal error. The proposed control strategy is analyzed to obtain the steady-state filter current error and ranges for the PI controller gains for stability. Simulation and experimental results are presented to show the effectiveness of the proposed shunt APF.
Air Quality Monitoring System Based on IoT Dineshkumar, T; Suresh Babu, V; Partheeban, Pachaivannan ...
Journal of physics. Conference series,
07/2021, Volume:
1964, Issue:
6
Journal Article
Peer reviewed
Open access
Abstract
The system presented in this paper is an advanced real-time air quality reporting system supported by the Internet of Things (IoT) architecture. Air quality in an environment heavily ...affected by the community’s state in a region may affect human, animal, and plant safety. Therefore, air quality levels in a region should be tracked regularly. This study aimed to build an IoT-based air quality system to evaluate air quality conditions in a given region. The device can track the air rates of different substances including O
3
, SO
2
, CO and particulate matter using sensors. Read the Arduino microcontroller sensor detail. The data sent to the cloud system then accessed the cloud system through a WIFI module on Arduino. The effects of the tracking are available through a cloud Site page. The current model is implemented successfully and can be deployed for real system implementations.
With an increase in population, there is an increase in the number of accidents that happen every minute. These road accidents are unpredictable. There are situations where most of the accidents ...could not be reported properly to nearby ambulances on time. In most of the cases, there is the unavailability of emergency services which lack in providing the first aid and timely service which can lead to loss of life by some minutes. Hence, there is a need to develop a system that caters to all these problems and can effectively function to overcome the delay time caused by the medical vehicles. The purpose of this paper is to introduce a framework using IoT, which helps in detecting car accidents and notifying them immediately. This can be achieved by integrating smart sensors with a microcontroller within the car that can trigger at the time of an accident. The other modules like GPS and GSM are integrated with the system to obtain the location coordinates of the accidents and sending it to registered numbers and nearby ambulance to notify them about the accident to obtain immediate help at the location.
Electric motors are the most widely used actuators for converting electrical to mechanical energy. Stepper motors perform various automated tasks because their position control is accurate. The ...operation of these devices at high speeds reduces the time required to perform automated operations. However, this can create inconveniences such as loss or excess of steps, with a consequent positioning error. Controlling the motor using a speed profile is the most commonly employed technique for avoiding this problem. Its generation usually requires hardware with high computing power, such as digital signal processors or field programmable gate arrays, and algorithms requiring specifications not published in the motor datasheet. In this study, we implemented an algorithm to simplify the generation of speed profiles. In the acceleration and deceleration regions, the velocity follows a logarithmic, quasi-linear, quadratic, or sinusoidal pattern. The algorithm provides position and time arrays. The speed and acceleration can be calculated in terms of time using numerical derivatives. The simulation results were validated using two microcontrollers to control a stepper motor programmed on Arduino and Micropython platforms. Experimental measurements using an encoder, gyroscope, and accelerometer validated the kinematic response of the stepper motor. These values are in a good agreement with the simulation results.
In this article, an efficiency-oriented control strategy is proposed for LCC-LCC-compensated wireless power transfer (WPT) system to achieve zero-voltage-switching (ZVS) operation over a wide current ...regulation range, in which full-bridge (FB) and half-bridge (HB) modes are combined and switchable based on requirements from load. The harmonic-considered time-domain models for FB and HB modes are first built to calculate current through the switches at the turn- off moment accurately. Then, focused on the constant voltage charge stage with variable output current, the ZVS boundaries are identified in HB and FB modes as the preferable control trajectories, which determines the desired current output with joint considerations of frequency, phase-shift angle, and duty ratio. Next, a least squares optimization method is introduced to fit the theoretical control trajectories into a smooth curve that is practical for implementation on microcontrollers. Finally, a 4.4-kW WPT prototype is built to verify the feasibility and validity of the proposed control strategy. Results show that a high system efficiency can be achieved over a wide output current range, with an efficiency of 94.68% even at 20% rated power.
The understanding of how bioinspired artificial microrobots propel themselves by propagating a planar wave along their flagellum is crucial to improve their mechanical design, as well as their ...performance. Likewise, the implementation of such a planar wave motion in N-link swimming microrobots involves several challenges, among with the motion control of actuators can be highlighted, whose load (viscous drag forces) does not only depend on their own link and motion, but also on their position along the flagellum. This paper proposes an improved locomotion for an N-link artificial Eukaryotic flagellum (AEF) swimming microrobot taking into account a fractional order approach for both the waveform design for propulsion and the control of the flagellum distributed dynamics. On the one hand, the novel way of swimming, based on a fractional order power law for the amplitude modulation, allows to preserve the motion properties obtained applying classical traveling waveforms, but presenting some benefits in terms of propulsion. On the other, a robust fractional order proportional-derivative (PDμ) controller is designed for the motion control of the microrobot. To demonstrate the advantages and validate both the waveform and the control strategy proposed, a hardware-in-the-loop (HIL) testbed for a 4-link robot is built. It consists of a microrobot simulator developed with the physical modeling tools in the MATLAB/Simulink environment and the embedded microcontroller Atmel ATmega32u4, where the control of the robot is programmed. The testbed, thanks to the simulator, allows to select different modes of swimming and geometry for the microrobot, as well as evaluating the performance of the locomotion in terms of propulsion, power efficiency or tracking. Experimental and simulation results are given to show that the best efficiency, with regard to both the way of swimming and the energy consumption with the control applied, is achieved with the proposed fractional approach.
•ELM-based Embedded decision support system for ultrasound nondestructive evaluation.•Comparison between PCA and ELM Autoencoders for ultrasonic feature set reduction.•Evaluation of ELM performance ...regarding four probability density functions.•ELM’s random weights quantization achieved good performance with small bit count.•ELM networks trained in microcontroller showed good time and accuracy performances.
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Decision support systems for nondestructive evaluation of defects are often trained on a personal computer environment, which may slow the assessment task. This work investigates the feasibility of embedding extreme learning machines in microcontrollers, in order to execute in situ training for an ultrasound nondestructive evaluation. Principal component analysis and autoencoders were evaluated as dimensionality reduction methods in a data set acquired from welded SAE 1020 carbon steel plates containing four types of defects. A binary-encoded random weight approach is proposed, whose results were tested over four different probability density functions used to generate the random weights. The obtained experimental results matched the accuracy of a previous work, run in computer environment for higher dimensionality data. In this work a dimensionality reduction of 75% and elapsed time for system training of less than 0.5 ms in microcontroller were achieved, indicating the suitability of such embedded networks for the studied case.
Abstract
The article discusses the results of the development and research of controlled electrical preheating of casting troughs and intermediate tanks in the system of transport trays for pouring ...aluminum melt. Electric heating contributes to high-quality and safe pouring of the melt in the cold shop. The heating of the casting track links eliminates the possibility of an explosion when the melt contacts water or ice, and also maintains the fluidity of the metal and limits the temperature gradient in the melt. Evaluation of the efficiency of the heater system was carried out on the basis of mathematical modeling of thermohydrodynamic processes in the melt. Acceptable characteristics of the section of the trays were determined to improve the distribution of metal by the melting and casting complex. To ensure the electrical safety of the equipment, it is proposed to power the heaters at a reduced voltage. Changing the intensity of heating is implemented by switching the windings of a group of power transformers from a delta connection to a star connection. Preheating controls are built in the form of a relay-contactor subsystem integrated into the microcontroller control system of the foundry complex.
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