Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"variable speed drives"”.
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The impact of variable speed drives on energy efficient induction motors
… incentives to its industrial customers to speed up this process.
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Design of a PC based Data Acquistion System for a Switched Reluctance Motor
… have gained considerable attention in the variable speed drive market mainly due to the simple construction of the motor and the possibility of developing low cost converters and controllers. As these machines are under development, a considerable amount of research effort is directed to …
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Fault tolerant behavior of advanced control schemes of induction machine drives
Power electronics based variable-speed drives offer energy saving solutions, providing precise control and quick response time. They are required for sensitive process control in industrial applications and other emerging technologies such as electric vehicles. This thesis examines two popular …
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Induction motor variable speed drive performance and impact on energy savings
… under or overvoltages on induction machines (1M) variable speed drives. In addition the performance with PWM inverters connected to 1M via long cables is also studied. The project starts by an evaluation of previous work on the subject and related topics. Relevant conclusions are made based on the …
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Induction motors with modulated terminal voltage
Following the development of high speed solid state switches for the forced commutation of current in AC power circuits it has become feasible to apply forced commutation techniques to the frequency and voltage control of induction motors as variable speed drives. The availability of these methods …
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Computer aided design of protection systems for electrical drives
… applied to the protection systems of electrical drives, removing much of the repetitive procedures presently used in determining relay settings. To further this aim, a series of algorithms have been devised which allow exploitation of the concept. The areas chosen for demonstration are, …
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Superheat control for air conditioning and refrigeration systems: Simulation and experiments
… emergence of the electronic expansion valve and variable speed drives has made immense impacts on the ability to regulate system parameters, resulting in important strides towards efficiency improvement. This research presents tools and methodologies for model development and controller design …
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On site measurements of kraft pulp pump system efficiency
… and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be …
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Vector controlled induction motor drive systems
… the years, dc motors have been widely used for variable speed drives for numerous industrial applications despite the fact that ac machines are robust, less expensive, and have low inertia rotors. The main disadvantage of the ac machines is the complexity in control and the cost of the related …
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Variable-Speed Switched Reluctance Motor Drives for Low-Cost, High-Volume Applications
Demand for energy-saving variable speed drives in low-cost, high-volume appliances has increased due to energy and environmental concerns and hence the need to comply with new regulations. Switched reluctance motor (SRMs) have been considered by many as attractive alternatives for brush commutated …
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Design and steady-state analysis of the switched reluctance motor drive
… decades there has been a revival of interest in variable reluctance drives mainly due to the advent of high power semiconductor devices and improvements in the understanding of the principles of electromagnetic energy conversion. In particular, the switched reluctance motor (SRM) has received …
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Improvements in direct torque control of induction motors
… control of the electrical motor by means of a variable speed drive incorporating sophisticated control strategies. Besides the expectations that have to be met concerning the motion control, other aspects such as efficiency, reliability, generation of electromagnetic pollution, etc. have become …
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Control of Harmonics in 6-Pulse Rectifiers
… i.e. non linear loads, the use of the variable speed drives are increasing day by day. Harmonics produced by non-linear loads are a potential risk if they are not evaluated, predicted, and controlled.</p> <p>The power electronic switching devices like thyristor used in the rectifier …
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Supercapacitor assisted LED (SCALED) converter technique for solar powered DC-microgrids
… DC-AC converters to supply motors controlled by variable speed drives. The overall efficiency of an electronic device with multiple voltage converters is determined by the product of the efficiencies of the individual conversion stages. Thus, overall efficiency drops drastically with the number …
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Energy efficiency analysis of converter-fed induction motors
… consumers of industrial electrical energy. As Variable Speed Drives continue to dominate various industrial processes, there is need for stakeholders to fully understand and quantify the converter-fed motor losses over a wide range of operating conditions. Such knowledge is crucial for both …
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Switched-doubly-fed-machine drive for high power applications
… approach to realize this "knob" is through variable-speed drives (VSD), which are power-electronic based converters with associated control operating as an interface between the electrical machine and the electrical source. These drives are not only critical in a wide range of applications …
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Modulation and control strategies for multilevel five-phase open-end winding drives
… an increased interest in medium- and high-power variable speed drives. Despite constant progress in the technology, the semiconductor characteristics are still the bottleneck in drive designs, due to their limitations to block high voltage (several kilovolts) and conduct high current (several …
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Novel Multilevel Converter for Variable-Speed Medium Voltage Switched Reluctance Motor Drives
… converter that is especially suited for high speed multi-megawatt switched reluctance motor drives operating at the medium voltage level is presented. The drive is capable of variable speed, four-quadrant operation. Each phase leg of the converter contains an arbitrary number of cascaded cells …
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Analysis of Electric Disturbances from the Static Frequency Converter of a Pumped Storage Station
The present work studies the disturbances created in the electric system of a pumped storage power plant, which is an hydraulic generation facility where the machines can work as turbines or pumps, by the operation of a static frequency converter (SFC). The SFC is used for starting the synchronous …
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Impact of Thermally Activated Building Systems (TABS) in Office Buildings
… a model consisting of physical and personal variables to quantify a person's thermal comfort within a building. The physical variables include air temperature, relative humidity, mean radiant temperature, and air velocity, and the personal variables include activity level and clothing …