| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic bearing device reduced in circuit scale and appropriate to lower the frequency of the carrier. SOLUTION: A differential signal from a sensor circuit 2B is converted to a digital value by an A/D converter 301, and input to a DSP307. Thereafter, the differential signal is divided into two, and one of the differential signals is multiplied by a sinusoidal discrete value signal from a sinusoidal discrete value arithmetic unit 320, and the other of the differential signals is multiplied by a cosinusoidal discrete value signal from a cosinusoidal descrete value arithmetic unit 321. Each of the signals after multiplication is filtered in a low-pass filter arithmetic unit 315, and squared in a square multiplication arithmetic unit 322. A result of each of the square multiplication is added in an addition unit 323, and a square root thereof is obtained in a square root arithmetic unit 324, and thereafter, gain offset correction is performed. A control signal to an excitation amplifier is generated on the basis of the signal obtained by the gain offset correction. COPYRIGHT: (C)2004,JPO
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