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Title: Sensorless control strategies for low-cost, high-speed electrical drive systems
Author: Bateman, Christopher John
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2010
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Brushless machine topologies have highly favourable qualities for certain applications: no commutator means these machines can be operated at extremely high speeds and because there are no brushes to wear out they are very reliable. It is necessary to know the position of the rotor to operate the machine - this function is performed by the commutator in brushed machine types. For a brushless machine some form of position sensor is normally used to provide the required position information, however, this has drawbacks. Some position sensors can be quite costly and they are often unreliable when operated in hot, electrically noisy environments; decreasing the reliability of an otherwise extremely dependable machine. Several 'sensorless' control schemes have been developed over the years to remove the need for position sensors. This EngD thesis is split into two parts. The first part focuses on a 1,600W, lOO,OOOrpm switched reluctance machine and drive system, used in several products produced by Dyson Ltd. An existing, high-speed, sensorless, control strategy is applied to the machine and the stability of the scheme is analysed. The main challenge with applying a sensorless scheme to this system is the varying nature of the DC link voltage, present due to the low DC link capacitance, which is necessary to reduce costs. A major contribution of this work is the meeting of this challenge. The second part of the thesis examines a 200W, lOO,OOOrpm,battery powered brushless DC machine and a 1,600W, lOO,OOOrpm, mains voltage powered brushless DC machine. A low-speed and high-speed sensorless control system is implemented on the 200W system and the same high-speed sensorless scheme is applied to the 1,600W system. The main difficulty with these machines is that they are single-phase and many existing sensorless methods cannot be applied to them. As with the switched reluctance machine in part one, the 1,600W brushless DC machine has a varying DC link voltage. The main aims were to produce extremely low-cost, reliable sensorless systems that will replace the existing position sensors used on the drives and operate the machines to speeds in excess of 100,000rpm.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available