Active magnetic bearing rotor falling protection method

[0010] The present invention is an active magnetic bearing rotor drop protection method. According to the detected rotor state, the magnetic bearing coil group can be controlled to be connected to the normal suspension branch or the drop protection branch, so as to realize the safe and stable operation of the rotor. It mainly includes: system power supply unit, position detection unit, control unit, normal suspension branch, drop protection branch and magnetic bearing coil group. The system power supply unit of the present invention includes filter, rectification and voltage conversion circuits, which provide corresponding stable DC voltages for the position detection unit, the control unit, the normal suspension branch and the drop protection branch. The position detection unit of the present invention includes a distance sensor installed at two radial magnetic bearings to measure the position of the rotor in two orthogonal radial directions x and y, and a distance sensor installed at the axial magnetic bearing to measure the distance of the axial position of the rotor Sensors, which output the measured distance as a voltage signal to the control unit. The control unit of the present invention converts, judges and calculates the signals transmitted from the position detection unit, and outputs corresponding execution signals to the normal suspension branch and the drop protection branch at the same time. The normal suspension branch of the present invention includes a drive switch and a coil drive unit. The drive switch is a group of relays, which are controlled by the control unit. The coil driving unit includes multiple power amplifier circuits, which are controlled by the control unit to provide controllable currents for multiple sets of magnetic bearing coils. The drop protection branch circuit of the present invention includes a protection switch composed of a group of relays, which is controlled to be turned off and turned on by a control unit, and provides a fixed and reliable current for multiple sets of magnetic bearing coil groups when turned on. The magnetic bearing coil set of the present invention includes multiple sets of coils arranged in the x and y directions of the two radial magnetic bearings and multiple sets of coils on the axial magnetic bearing, and is powered by a normal suspension branch or a drop protection branch. When the rotor is suspended normally, the control unit controls the magnetic bearing coil set to be connected to the normal suspension branch, and at the same time controls the magnitude of the current in the coil to make the rotor stably levitate; when the rotor falls, the control unit controls the magnetic bearing coil set to connect to the drop protection branch , at this time, the current in the coil is large and fixed, and the rotor is quickly adsorbed and fixed in a certain position.

[0011] Contents that are not described in detail in the specification of the present invention belong to the prior art known to those skilled in the art.

[0012] In addition, it should be pointed out that the names and forms of the components described in the present invention may be different, and all modifications, additions and improvements made according to the structures, features and principles of the present invention should be regarded as the protection scope of the present invention.