Patent attributes
An object of the present invention is to provide a magnetic bearing device designed to achieve reduction in cost and size of a circuit by omitting a DC/DC converter that has been used for obtaining a control power voltage of a magnetic bearing, and to provide a vacuum pump having the magnetic bearing device. The magnetic bearing device has: position detection means for detecting a radial position and an axial position of a rotor; magnetic bearing means for controlling the radial position and the axial position with an electromagnet based on the radial position and the axial position detected by the position detection means; an excitation circuit that includes a switching element for connecting/disconnecting between the electromagnet and a power supply; electromagnetic current detection means for detecting a signal of a current flowing through the electromagnet; power supply voltage detection means for detecting a signal of a voltage of the power supply; and pulse width calculation means for calculating, at each timing, a pulse width for operating pulse control for the switching element. The pulse width is calculated based on the voltage of the power supply detected by the power supply voltage detection means and the current detected by the electromagnetic current detection means.
