Self-sensing active magnetic levitation

A magnetic levitation method that combines all the known advantages of active magnetic bearings in a self-sensing configuration is presented. The method realizes stable and well-damped levitation without any sensor hardware at the rotor. This is achieved by using the coil voltage of the magnetic bearing as system input (voltage instead of current amplifiers) and the current as system output. The resulting system is observable and controllable in the sense of control theory, allowing a magnetic bearing to be stabilized with a simple linear controller using current measurements alone. Several self-sensing bearings have been constructed. Their performance is comparable to systems with sensors, but hardware requirements and costs are substantially reduced. Experimental results are included.<
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