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In the scientific literature and designing practice of supported mining pillars lots of methods are presented. Mining pillars are part of the rock being left in excavation in order to support the floor. In this article, in order to design supported mining pillars, we are using the Mohr-Coulomb yield criterion. The fundamental idea of the paper was to investigate how the top support in mining excavation...
The story about resonant circuits it's important for understanding the operation behavior of resonant power converter. The aim of this study is to made the student's to understand how can they apply mathematics relations in study of this phenomenon and to know how we can apply it in power supply circuits. For the resonance we must have at least two reactive components. One of these components is a...
This paper intends to present a model of power transformers used in simulation of power inverters. Electromagnetic induction refers to the phenomenon by witch electric current is generated in a closed circuit by the fluctuation of current in another circuit placed next to it. For modeling of power transformers, we implemented a Matlab software, based on mathematical equations who describe the functionality...
This paper present a study about a power supply, study which can be applied to another supply circuits. This study can be useful also in the learning process. I start the study from modulation of mathematical equations for Flyback Converter. I demonstrate the difference between Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) true the Matlab graphics. I made analytic numerical...
The vibrating wire transducer represents, basically, a damped oscillating resonant circuit tuned on the vibrating wire mechanical resonant frequency. Determining the equivalent electrical circuit for vibrating wire transducers without mutual couplings is a very important step because implementing PSPICE models for the behavior analysis cannot be made correctly with mutually coupled impedances. The...
This paper proposes a Matlab platform used in a student's educational activities in order to acquire a better understanding of operational amplifiers functionality, and the basic properties of operational amplifiers and the non-ideal characteristics of the operational amplifiers. The Matlab platform is based upon a study about inverting or non-inverting amplifiers, comparators with or without feedback,...
The goal of increase power at idle speed for alternators and less fuel consumption, also the increase in electrical load, require increasing the power output capability of an alternator. In this paper the author presents some practical solutions for improving the performances of power equipment, and mainly, of power sources from automotive. Still, considering the broad spectrum of the problem and...
The vibrating wire transducer represents, basically, a damped oscillating resonant circuit tuned on the vibrating wire mechanical resonant frequency and measure the majority of the physical input parameters (forces, strains etc.) in hydro-technical buildings. In order to implement an automatic data acquisition system for dams monitoring, which measures the output signal frequency of those transducers,...
This paper proposes a switching power converter that allows determining the ESR value for a supercapacitor. The model proposed intends to be one of the future methods for charging of the supercapacitor tacking into account the necessary charging conditions, constant current and maximum voltage across the capacitor. Also this model of converter propose by us can be used for other types of supercapacitors...
This paper presents a study of the Buck converter with closed-loop control and a Matlab simulation of this converter model. The closed-loop allows to regulated the output voltage for input voltage and load variation. The Matlab model is composed of the differential equations that define the implemented system. In order to implemented the simulation platform, the converter operation was described by...
Class E switching-mode tuned power amplifier offers high efficiency at high frequencies. Class E power amplifier concept, introduced by Sokal, is not defined by a special topology. The most simple topology for class E power amplifier consists in a single switch device that operate at carrier frequency of the output signal and a load network that must extract only a single spectral frequency component...
All induction heating applied systems are developed using electromagnetic induction. Electromagnetic induction refers to the phenomenon by which electric current is generated in a closed circuit by the fluctuation of current in another circuit placed next to it. The basic principle of induction heating is that AC current flowing through a circuit affects the magnetic movement of a secondary circuit...
Data converters are essential parts that enable communication between the external analog world and the digital devices. They should not compromise precision even though the hardware in which they are implemented relies on semiconductor devices known for their poor accuracy. Experimentation is essential to become fully acquainted with the converters performances. Theory is generally unable to quantitatively...
The paper presents a study about half bridge invertors and a MATLAB tool for simulation this type of invertors. This tool describes a comparison between two modes of solution for differential equation. The period of commutation is divided in four intervals. Interval one, when we want to open Q1 transistor, interval two and four when all component are blocked, and interval three when we want to open...
In this paper we intend to present a new architecture of direct digital frequency synthesis (DDFS) which want to reduce the switching time between two different frequencies. We start from a classical DDFS which was first implemented on a FPGA device presented in paper using the Tierney architecture. In paper is presented a classical DDFS architecture and in this paper we present a new architecture...
The intent of this presentation is to present the influence of power level delivered on a load over the total harmonic distorsion of input current for a power half-bridge inverter with resonant load. Half-bridge inverter is a configuration used for higher output power applications compared to single end quasi-resonant inverter. Even though it needs complicated control, half-bridge configuration has...
Many products currently take advantage of microcontroller and are capable of creating an analogue - to - digital (A/D) converter with very little extra hardware or software. In effort to make the design more competitive, the typical successive approximation A/D converter (ADC), on board, can be replaced by several low - cost A/D PWM converter structure. The designer must first determine the true system...
When measuring level in wells or vessels using ultrasonic pulse-echo techniques, carefully positioned, narrow beam angle transducers are usually employed. When it comes to small cross sections, a sufficiently narrow beam transducer is hard to find. That is why the possibility of using large beam angle transducer had been investigated. Experiments were carried out, showing that in certain conditions,...
This paper presents a Matlab tool to simulate dc-dc converters based on the differential equations which describe the behavior of the converter for the two states: when transistor is "on" and when the transistor is "off". The advantage of this tool consists in the possibility to show to the students how the professional tools work and also help them to understand more deeply the...
Switching regulators offer two main advantages compared to the linear regulators. First, switching efficiency is much better than linear. Second, because less energy is lost in the transfer, smaller components and less thermal management are required. A switching power supply has to assure the stability between input and output voltage, the stability between load and output voltage, and a good transient...
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