Magnetic bearing device with vibration restraining function, magnetic bearing device with vibration estimating function, and pump device with the magnetic bearing devices mounted thereto

A magnetic bearing device with a vibration restraining function, comprising:

• a rotor;
• electromagnets applying a levitating force to the rotor;
• a stator portion to which the electromagnets are secured;
• displacement detecting means for detecting one of radial and axial relative displacement of the rotor with respect to the stator portion;
• a magnetic bearing control compensator that calculates an adjusting amount of the levitating force on the basis of the relative displacement detected by the displacement detecting means;
• electromagnet control means for adjusting the levitating force in correspondence with a calculation result of the adjusting amount of the levitating force obtained by the magnetic bearing control compensator;
• vibration detecting means for detecting a predetermined physical amount of a stationary apparatus portion whose position relative to the stator portion is fixed;
• and
• adding means for adding an output of the vibration detecting means, with a polarity of the output reversed, to a transfer signal of magnetic bearing feedback control means formed at least by the displacement detecting means, the magnetic bearing control compensator, and the electromagnet control means,
• wherein the predetermined physical amount is at least one of an acceleration of the stationary apparatus portion and the stator portion, a displacement, a speed, and an addition acceleration, each of the displacement, the speed, and the addition acceleration being obtained by one of differentiating and integrating the acceleration a requisite number of times, and
• wherein the acceleration is a subtraction result obtained by subtracting a result obtained by performing second-order differentiation on the relative displacement of the rotor detected by the displacement detecting means, from a third multiplication result obtained by multiplying one of the calculation result of the adjusting amount of the levitating force obtained by the magnetic bearing control compensator and an addition result obtained by the adding means by a reciprocal of a mass of the rotor.

A magnetic bearing device with a vibration estimating function, comprising:

• a rotor;
• electromagnets applying a levitating force to the rotor;
• a stator portion to which the electromagnets are secured;
• displacement detecting means for detecting one of radial and axial relative displacement of the rotor with respect to the stator portion;
• a magnetic bearing control compensator that calculates an adjusting amount of the levitating force based on the displacement detected by the displacement detecting means;
• electromagnet control means for adjusting the levitating force in correspondence with a calculation result of the adjusting amount of the levitating force obtained by the magnetic bearing control compensator;
• vibration detecting means for detecting a predetermined physical amount of a stationary apparatus portion whose relative position with respect to the stator portion is fixed;
• and
• adding means for adding an output of the vibration detecting means, with a polarity of the output reversed, to a transfer signal of magnetic bearing feedback control means formed at least by the displacement detecting means, the magnetic bearing control compensator, and the electromagnet control means,
• wherein the predetermined physical amount is at least one of an acceleration of the stationary apparatus portion and the stator portion, a displacement, a speed, and an addition acceleration, each of the displacement, the speed, and the addition acceleration being obtained by one of differentiating and integrating the acceleration a requisite number of times, and
• wherein the acceleration is a transformation result obtained through transformation of a first multiplication result into time domain, the first multiplication result being obtained by multiplying a Laplace transformation of the relative displacement of the rotor detected by the displacement detecting means by a predetermined transfer function.

A magnetic bearing device with a vibration estimating function, comprising:

• a rotor;
• electromagnets applying a levitating force to the rotor;
• a stator portion to which the electromagnets are secured;
• displacement detecting means for detecting one of radial and axial relative displacement of the rotor with respect to the stator portion;
• magnetic bearing control compensator that calculates an adjusting amount of the levitating force based on the displacement detected by the displacement detecting means;
• electromagnet control means for adjusting the levitating force in correspondence with a calculation result of the adjusting amount of the levitating force obtained by the magnetic bearing control compensator;
• vibration detecting means for detecting a predetermined physical amount of a stationary apparatus portion whose relative position with respect to the stator portion is fixed;
• and
• adding means for adding an output of the vibration detecting means, with a polarity of the output reversed, to a transfer signal of magnetic bearing feedback control means formed at least by the displacement detecting means, the magnetic bearing control compensator, and the electromagnet control means,
• wherein the predetermined physical amount is at least one of an acceleration of the stationary apparatus portion and the stator portion, a displacement, a speed, and an addition acceleration, each of the displacement, the speed, and the addition acceleration being obtained by one of differentiating and integrating the acceleration a requisite number of times, and
• wherein the acceleration is a subtraction result obtained through subtraction of a result obtained by performing second-order differentiation on the relative displacement of the rotor detected by the displacement detecting means, from a third multiplication result obtained by multiplying one of the calculation result of the adjusting amount of the levitating force obtained by the magnetic bearing control compensator and an addition result obtained by the adding means by a reciprocal of a mass of the rotor.