Five-degree-of-freedom (five-DOF) bearing-free permanent magnet synchronous motor

Abstract

The invention discloses a five-degree-of-freedom (five-DOF) bearing-free permanent magnet synchronous motor. Left and right conical bearing-free permanent magnet synchronous motors respectively arranged at the left and right ends of a motor shell are symmetrically connected to a mechanical rotating shaft; each conical bearing-free permanent magnet synchronous motor consists of a conical stator, atorque winding, a suspension force winding and a conical rotor; and a permanent magnet is mounted on the outer surface of the conical rotor, a jacket is fixedly sleeved outside the permanent magnet, the conical rotor is fixedly arranged on the mechanical rotating shaft, the conical stator is provided with a plurality of through slots in the axial direction, each through slot is divided into an inner layer and an outer layer in the radial direction, the suspension force winding and the torque winding are respectively placed in the inner layer and the outer layer, the pole number of the torque winding is as same as that of the permanent magnet, and the difference between the pole number of the suspension force winding and the pole number of the torque winding is 2. The five-DOF bearing-freepermanent magnet synchronous motor can simultaneously realize radial and axial five-DOF suspension of the rotor without an additional magnetic bearing, has the advantages of high integration, reducedvolume and high critical rotating speed, and is easy to realize high-power ultrahigh-speed operation.

Description

technical field [0001] The invention belongs to the technical field of motors, in particular to a five-degree-of-freedom bearingless permanent magnet synchronous motor, which is suitable for many special power transmission occasions such as high-speed and ultra-high-speed direct drive electric spindles, semiconductor industry, flywheel energy storage, aerospace, etc. It is used in special occasions that require no contact, no lubrication and sealing, no friction and wear, vacuum technology, aseptic workshops, and clean rooms. Background technique [0002] Since a single bearingless permanent magnet synchronous motor can generally only constrain the two degrees of freedom in the radial direction of the rotor, if the stable suspension of the rotor is to be achieved, constraints must be imposed on five degrees of freedom at the same time. The traditional five-degree-of-freedom bearingless permanent magnet synchronous motor usually has the following four structures: [0003] 1....

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Problems solved by technology

[0007] Among them, the first three structures all use magnetic bearings, resulting in an increase in the axial length of the system, thereby reducing the critical speed of the motor and limiting the development of the motor to a higher speed and higher power, and the normal operation of the magnetic bearing requires A certain number of excitation coils, iron cores, expensive high-precision displacement sensors, and high-performance power amplifier drive circuits will greatly increase the cost of the system. Therefore, the comparison of the mechanical structure of the five-degree-of-freedom bearingless permanent magnet synchronous motor complex and high system cost; the fourth type of bearingless permanent magnet sheet motor is based on the use of bearingless technology to achieve radial two-degree-of-freedom suspension, and relies on magnetic resistance to achieve passive suspension on the other three degrees of freedom, thereby Abandoning the magnetic bearing simplifies the structure of the system and reduces the cost of the system, but the motor has the following defects: in order to achieve the passive control of the other three degrees of freedom by using magnetic resistance, the axial length of the motor rotor and its diameter The ratio must meet a certain range of values. Usually, the axial length of the rotor is much smaller than the diameter of the rotor, which brings problems to increase the power of the motor. The power of the motor cannot be increased by increasing the axial length of the rotor. It has become a fatal shortcoming of the motor, and because the other three degrees of freedom of the motor cannot be actively controlled, it is prone to instability in some high-speed and load-changing situations

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