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The aim of this paper is the conversion of the classical hysteresis controller into a constant frequency hysteresis current controller. The classical alternative to the hysteresis controller is the proportional-integrative controller which gives constant switching frequency and overall better performances with a cost of comprehensive parameter tuning and sensitivity at driven system change. The hysteresis...
This paper presents an active DC-traction substation with six-pulse uncontrolled rectifier, whose structure and control ensure the braking energy recovery and increased power quality in both traction and regeneration regimes. The key component in the power structure is a voltage source inverter-based shunt active power filter connected properly between the DC-traction line and the power supply. To...
The theoretical and experimental investigations presented in this paper are related to an LCL filter with damping resistance used to interface the voltage source inverter of an active DC-traction substation with the power supply. The case study of DC-traction system with six-pulse diode rectifier, as is the case of Bucharest subway substations, is taken into consideration. Starting from the configuration...
Main objective of this paper is to provide a practical tool for the analysis and study of power quality and deforming regime. The LabVIEW graphical programming environment is used for designing virtual instrument to achieve the main two objectives. First goal is synthesizing a distorted signal by adding a number of sinusoidal harmonics which composing it. An accurate voltage signal and the current...
This paper is focused on the possibilities of implementing an auto-adaptive control, without a phase-locked loop circuit, for the operating frequency in an induction heating system with single-phase voltage source inverter and resonant L-LC load. Based on the phasor diagram of the equivalent resonant load under resonance condition, three possibilities have been identified to express an error to be...
In this paper, using Lab VIEW graphical programming environment are made a number of virtual instruments which are used at the demo/study of low power active filters with operational amplifiers (op-amp). There are analyzed the active first order low pass, high pass and band pass filters. The results are included in two papers. The first one contains the simulation of active filters. The different...
This paper is concerned with the implementation of the Fryze-Buchholz-Depenbrock theory in the control of an active DC-traction substation. The active DC-traction substation taken into consideration is obtained by adding a specific system for active filtering and regeneration to a classical DC-traction substation with twelve-pulse uncontrolled rectifier. The main component is a voltage source inverter-based...
This paper focuses on the analysis of the power quality and energy efficiency in the Bucharest's subway traction substations and finding solutions for their improvement. Two directions are taken into consideration. The former consists in the active filtering of the current and the reactive power compensation, so that the traction substations to operate in conditions of unity power factor. The latter...
The main objective of this paper is to solve a practical and current problem, by taking advantage of the virtual instrumentation in testing electrical machines. The abilities of virtual instrumentation are used to data acquisition, measurement and analyze the values of no-load testing's parameters for three-phase induction motor. The virtual measurement system bench is designed and consist from two...
In this paper an modern solution to measure and analyse selected parameters of variable reluctance synchronous motor is presented. An virtual instrument with multiple options for selecting the analyzed parameters is described. The values of motor measurement voltages, currents and speed are read from a specified folder. With present virtual instrument it can be see the motor currents, voltages and...
This paper presents aspects regarding the saturation influence upon the operation of the reluctance synchronous motors in case of some representative dynamic regimes. In this purpose, there have been detailed the mathematical model and the Matlab model conceived with its help. There are also presented the simulations obtained for a few concrete situations. The paper ends with experimental results...
This paper is concerned with the practical implementation of some orthogonal reference frame based methods in the control of a shunt three-phase three wire active power line conditioner in order to compensate unbalanced nonlinear loads under nonideal voltage conditions. The first two developments are based on the components of voltage and current space vectors in the orthogonal stationary reference...
This paper investigates the effects of the matching inductance on the quality of the power transfer in the induction heating system with voltage inverter and parallel resonance. Two analyzing methods are used for the matching inductance effect on the current through the inverter and the current through the equivalent inductor. It is shown that there is an optimal value of the matching inductance that...
In this paper, using Lab VIEW graphical programming environment is realized a virtual instrument (VI) which is used at the study of single-phase AC unknown load. In this study the circuit of unknown load is analyzed in case of sinusoidal permanent regime. The voltage and current of the load are the main input parameters used in this study. They are represented as phasors in the complex plane. Also...
In this paper, using Lab View graphical programming environment are implemented the virtual instrumentation's concept, realizing three virtual instruments which are been used at the study of asynchronous motor functional characteristics. In this study, the asynchronous motor is in case of steady state regime. It starts from the per phase equivalent diagram in T for these Virtual Instruments designed...
The aim of this paper is to identify an optimum control strategy of three-phase shunt active filters to minimize the total harmonic distortion factor of the supply current. Some design aspects starting from power that must be compensated are taken into consideration. The DC-bus capacitor operation has been simulated using Matlab-Simulink environment and the results are very interesting. It is shown...
This paper focuses on the harmonic at the network of the driving systems with DC motors and controlled rectifier. Notably, the total harmonic distortion factor (THD) is influenced by the rectifier commutation and by the load current filtering. We found these influences (thyristors commutation and filtering inductivity) concerning the waves of the currents in the secondary of the transformer and in...
In an efficient process drive, the monitoring function is absolutely necessary because decision can be taken only based on correct and complete information about the parameters which characterize the process. An example of a process which requires such a monitoring is represented by the one associated to a electrical energy flow supervision system, which has the purpose of monitoring and storing the...
This paper focuses on the harmonic at the network of the driving systems with DC motors and controlled rectifier. Notably, the total harmonic distortion factor (THD) is influenced by the rectifier commutation and by the load current filtering. We found these influences (thyristors commutation and filtering inductivity) concerning the waves of the currents in the secondary of the transformer and in...
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