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The rotor flux vector is used to calculate the flux angle for coordinate transformation, feed the control signal for d-axis controller and synthesize the de coupling voltage for independent d and q axis currents control. Various methods are developed to find the flux vector of induction motor for direct rotor field oriented control; direct measurement and estimation methods. This paper is on speed control of induction motor using space vector PWM. Vector control which controls independantly flux and torque current component in order to drive induction motor, is applied for driving motor. In this paper, the performance of the proposed anti-windup control is verifed by experimentation under various conditions with an induction motor drive system composed a high speed DSP controlled, an AC-DC-AC converter and induction motor.
Direct Torque Control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement However, DTC do not show good performance at low speed range with conventional open loop stator flux observer when stator resistance varied So, authors proposed nonlinear stator flux obsever in order to flux estimation at low speed and show its simulation results
Solar energy converters were used to convert the electrical energy from the solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC/DC converters of different types in a solar energy system in order to investigate the performance of the converters. A simple method which combines a discrete time control and a PI compensator is used to track the maximum power point of the solar array. The system is kept to operate close to MPPT's thus the maximum possible power transfer from the solar array is achieved. Experimental tests were carried out for buck, boost and buck-boost converters using a simple maximum power point tracking algorithm.
The main problems in photovoltaic performance measurement arises from the fact that solar cells have a highly selective spectral response and are, therefore, very sensitive to the spectral composition of the incident radiation. Outdoors, this varies considerably with location, weather, time of year and time of day, Indoors, it depends on the type of simulator used and it can change as the equipment ages. Unless measurement procedures take account of these variations and other difficulties, such as the marked temperature dependence of solar cell, the results can be grossly erroneous. Performance rakings of the same module by laboratory have been know to disagree by as much as 20%.
The noise of the most industrial universal motor are mainly caused by the electromagnetic effect. This kind of noise can be amplified by the structure itself, if the frequency components of the magnetomotive force are close to the resonance frequencies of the structure. Therefore, there must be an intermediate process which usually called structure dynamic modification to avoid this phenomenon. In order to yield the input forces for the motor, analytical forms of magnetomotive force were obtained and those were feed to do response analysis. Through these analysis, some design guide were suggested to reduce the vibration of the universal motor.
A complete computerized system for the characterization and performance testing of photovoltaics(PV) modules under natural sunlight and ambient condition was designed. I-V characteristics of PV module provides on essential diagnostic means in assessing the performance and internal cell parameters of PV module depends on its basic materials, manufacturing technology and operating environmental conditions. I-V curves derived from PV modules refect to a large extent the physical properties and their expected performance. In this paper, Electrical performance measurement and evaluation methods for solar cell module by MOSFET variable Load were studied. Also, Mathematical model and theory of solar cell associated with the photovoltaic effect has been discribed.
The results of an investigation performed for the purpose of developing an adaptive state-of-charge indicator for use in estimating reserve-time during a battery discharge are discussed. A dimensional analysis on the discharge characteristics of AT&T Lineage^(Tm) 2000 Round Cells in the useful range of discharge led to the identification of the relevant physical variables and constants needed to describe the discharge behavior quantitatively. This analysis provided the basis for the proposed algorithm which involves analyzing actual discharge behavior in real-time accordingly. The proposed algorithm was tested with actual discharge data from constant current and variable current discharges.
A single-phase PWM current source rectifier with a neutral leg is presented and throughly analyzed in this paper. This novel topology is implemented by adding an extra leg a step-down single phase PWM space vector modulation method to reduce the dc output voltage harmonics. The PWM pattern generation need a digital system. As compared with a conventional single-phase PWM rectifier, over 20% improvement of the total harmonics distortion in the output voltage can be obtained. Different SVM techniques are analyzed for this PWM rectifier and simulation results are presented.