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Yaw error measurements using a yaw sensor have been carried out to determine the characteristics of yaw errors and analyze the behaviors of the structural guide. The modification of yaw sensor design is necessary to improve the yaw error measurement. The contactless of a magnetic levitation technique that is supported a load of magnetic bearing. It is more suitable for reduction of yaw measurement...
This paper describes a simple ripple compensation method of suspension force and torque in a bearingless surface-mounted permanent magnet (SPM) motor with two-phase integrated winding configuration. Only two H-bridges or eight power transistors are used for the proposed topology. The neutral point of each phase is connected to the middle point of the power sources to superimpose the suspension and...
Magnetic suspension pumps have been attracted attention and actively developed. These pumps can realize magnetic suspension and rotation of a rotor shaft integrated with an impeller without mechanical contact. There is now a need to develop a magnetic suspension pump that is capable of 5-axis active control while retaining a small size and low power output. However, conventional structures capable...
The feasibility of zero-power control in flux-path control magnetic suspension is discussed. In the flux-path control magnetic suspension system, ferromagnetic control plates are inserted between a permanent magnet (magnetic source) and a floator and moved to vary the flux from the magnetic source to the floator. The zero-power control has been applied in active magnetic suspension with a DC electromagnet...
The controllability of gyroscopic systems is studied analytically. Two rotational motions of the rotor interact each other due to gyroscopic effects when the rotor is rotating. They are usually controlled with two control inputs in totally active magnetic bearing systems. Meanwhile, two degrees of freedom are controlled with a single control input in double parallel magnetic suspension systems. Such...
The magnetic bearing using the high temperature bulk superconductor (HTS) has been developed. In this system, the ring shaped permanent magnet is installed in the rotor. It has two poles. This configuration realizes increment of the linkage flux of the surface of the HTS on the stator. Pinning force of the HTS is used to support the rotor weight and keep the rotor stability. Pinning force depends...
This paper investigates the cross-coupling effect of a 3 degrees of freedom magnetic bearing (3-DOF MB) using the magnetic circuit method comprehensively. The EMF of X-axis (or Y-axis) coil induced by the current variation Eix (Eiy) can vary in a range of up to 14.7% due to the cross-coupling caused by Z-axis current. Moreover, the X-axis (or Y-axis) force characteristics and stiffnesses are significantly...
The stability of magnetic bearings will seriously affect the overall operation of the motor. Magnetic bearing temperature is closely related to the performance of magnetic bearing (MB) system. Therefore, loss calculation and thermal estimation are very important in the design of MB system. A MB system including a pure radial magnetic bearing (RMB) and a combined radial and axial magnetic bearing (CRAMB)...
This paper developed a domestic magnetic flywheel energy storage system for brake energy regeneration in urban rail transit. To minimize the heating of flywheel, low-loss magnetic bearings and permanent magnet motor/generator are designed. Also the sensorless vector control based on sliding mode observer is discussed to achieve low cost and high reliability. The experimental results verify the robustness...
A hybrid foil-magnetic bearing (HFMB) is a combination of the gas foil bearing (GFB) and the magnetic bearing (MB), which takes advantages of each individual bearing and compensates for their inherent weaknesses each other. However, control of the HFMB is different from that of the AMB considering the varying dynamic stiffness and damping coefficients of the GFB. This paper presents an adaptive control...
This paper presents a novel design of high-speed single-drive bearingless motor. Only axial direction is actively positioned, and then, radial and tilting directions are passively stabilized. The active axial force and rotational torque are generated by d- and q-axis currents, respectively. In order to reduce required d-axis current at start-up, comparisons of the magnetic suspension performances...
A novel control algorithm, one-cycle control, was adopted in five-phase six-leg switching power amplifiers for magnetic bearing. Mathematical models of current ripple were derived, from which methods to reduce the current ripple is obtained. Simulation and experiments were conducted on for different parameters. The results were compared with bipolar and unipolar one-cycle control, which agrees with...
In order to solve the heat dissipation problem of high-speed permanent magnet (PM) motor with magnetic bearings (MB), a stator jacket with water cooling and forced air convection cooling was designed. A multi-physics thermal analysis and design method based on coupling finite element method (FEM) and computational fluid dynamics (CFD) was presented. Two electrical machines, whose power is 30kW and...
To solve the problem of that some industrial high-speed rotation equipment has to pass through the first order bending critical speed at some special application, an electrical machine with a flexible rotor support by magnetic bearings (MB) was developed. The electrical machine, whose rated power is 315 kW and rated speed is 20000 rpm, was detailed designed and analyzed by multi-physics method. The...
A magnetically levitated motor can realize non-contact support of a rotor using magnetic force. Therefore, it has many advantages over conventional mechanical bearings. In order to accomplish complete magnetic levitation of the rotor, it is necessary to control five degrees of freedom actively. However, this gives rise to major issues such as complicated control system and associated electronics,...
This paper presents a novel axial vibration suppression method in two-axis actively positioned permanent magnet bearingless motors. Only radial x and y directions are actively positioned. The axial z and tilting θx and θy directions are passively stabilized by magnetic attraction force between the stator core and rotor permanent magnets. Therefore, damping force is not generated in the axial and tilting...
The ongoing miniaturization trend of electric machines demands for higher rotational speeds to provide a required power level at decreased size. The goal of this project is to push the limits of miniaturization by researching new concepts for bearingless machines with ultra-high rotational speeds exceeding 25 million rotations per minute (Mrpm). The employed sub-millimeter size spherical solid steel...
Interior permanent magnet (IPM) bearingless motors are becoming a good choice for high-speed applications. In these motors, reducing the thickness of the PM leads to the increase of the radial forces which affects the demagnetizing fields. Various types of PM motors have so far been recommended for enhancement of the radial forces and torque. In the proposed IPM motor the d-axis flux-linkage and the...
This paper proposes simple driving method for a two-degrees-of-freedom actively controlled bearingless disk motor using only one three-phase inverter. This bearingless motor has 6-slot/6-pole structure including single-phase 6-pole motor winding and three-phase 4-pole suspension winding. The single-phase motor winding is connected between the neutral point of the three-phase suspension winding and...
This paper investigates reduction in torque and suspension force ripples of an axial-gap type bearingless motor with one-degree-of-freedom (DOF) active positioning in the axial direction. This one-DOF controlled bearingless motor employs only one set of three-phase winding and one three-phase inverter, called a single-drive bearingless motor (SDBelM). The proposed axial-gap SDBelM combines a repulsive...
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