Patent ID: 7355833
Filing Date: 2008-04-08
Classification: F16C,G01B

Abstract:
1. A magnetic bearing device comprising: an electromagnet for supporting a member without contact; an excitation amplifier for supplying an excitation current to the electromagnet; a carrier wave generation device for generating a carrier wave; sensor means having at least one sensor for detecting displacement of the member, said sensor means modulating the carrier wave to output a sensor signal according to a position of the member and including a standard signal generation device for generating a carrier wave standard signal with specific amplitude according to the carrier wave, and a difference calculation device for calculating a difference between the sensor signal and the carrier wave standard signal; an A/D conversion device for converting the difference to a digital value; a demodulation calculation device for demodulating the sensor signal converted to the digital value through a digital calculation process; a control device for controlling the excitation amplifier according to a calculation result of the demodulation calculation device; and a phase shift device for shifting a phase of the carrier wave standard signal so that the carrier wave standard signal has a phase substantially same as that of the sensor signal.