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The task of this masters thesis is to investigate the properties of Natural Field Orientation, NFO, a new patented method for controlling the asynchronous motor. The intention is to see whether NFO would make it possible to, in the future, replace the expensive hydraulic motors that are being used in CelsiusTech Electronics' radar directors today with inexpensive hydraulic motors that are bein
Automatic control is increasingly used in mission critical applications. The reason for this is the potential benefits and the fact that control engineering is now able to deal with complex systems. Control of high performance aircrafts is a typical example. Considerable benefits can be obtained by having an aircraft that is unstable in certain flight conditions and providing stability with a cont
Backlash is common in mechanical and hydraulic systems. It severely limits the overall system performance. Many mechanical solutions have been developed to overcome backlash, for example by using spring-loaded split gear assemblies or dual motor systems. These mechanical solutions can satisfactorily handle the backlash problem but they give rise to other problems like decreased accuracy and reduce
This report investigates time optimization of a process where brazed heat exchangers are soldered in a vacuum furnace. This process consists of three phases, heating soldering and cooling. Physical models have been obtained by using stationary conditions. These are not sufficient to describe the actual very complex behavior. Instead, nonphysical models have been identified. Simulations of the heat
This report deals with the damping of sub-synchronous oscillations in power systems. The method is based on estimation of the generator rotor angle and shaft speed, by measuring the line current and the voltage across a phase-compensating series capacitor. These two signals are probably not sufficient, so a line-to-ground voltage measurement is added. However, this means increased costs. A thyrist
