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High speed motors rotating at speeds above 10,000 rpm are gaining more attention nowadays for various high performance applications. High efficiency and reliability are demanded by the applications like centrifugal compressors, pumps, machine tools, drills, aerospace etc. This paper presents novel design and analysis of a high speed axial flux permanent magnet motor for high speed, low power applications...
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...
Bearingless motors combine in the same structure the characteristics of conventional motors and magnetic bearings. Traditional bearingless machines rely on two independent sets of winding for suspension force and torque production, respectively. The proposed Multi-Sector Permanent Magnet (MSPM) motor exploits the spatial distribution of the multi-three-phase windings within the stator circumference...
A novel maglev wind yaw system (MWYS) with two groups of suspension windings is proposed to replace the traditional gear-driven yaw system of horizontal-axis wind turbines. In order to overcome the power difference between these two groups of suspension windings which could affect seriously the suspension stability, the windings optimization is carried out to decrease this difference. First, the dynamic...
A maglev wind yaw system (MWYS) is proposed to decrease the yaw power with the hybrid magnet. A disc motor and a variable speed gear are introduced to weaken the coupling between the suspension force and yaw torque. Firstly, we analyze the operation principal of the MWYS, and give the detailed description of the suspension weight and rotary torque. The rotor ample turns are given based on the Magnet...
Engineering often requires magnetic bearings with sufficient capacity and to reduce the volume as much as possible at the same time. In this paper, the design principles of air gap, magnetic pole, rotor, stator, magnetic pole area and coils are given on the basis of practical engineering experience. Radial magnetic bearing structure with different shaft diameters and different magnetic poles number...
Mechanical circulatory support using rotary ventricular assist devices (VADs) is one of the strongest therapy for heart disease patients. However, technical difficulties such as high mechanical durability, sufficient blood compatibility and small device size prevents VADs development for pediatric heart disease. In this study, an ultra-compact self-bearing motor whose diameter of 22 mm and height...
In flywheel system, rotor is supported by mechanical bearing. In the cases that the weight of the rotor is heavy and the rotational speed is high, mechanical loss is large. Superconducting magnetic bearing (SMB) is introduced to support with contact-less and control-less. The rotor is supported by the pinning effect in SMB. Pinning force depends on the specification of the HTS. In this paper, the...
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...
Traditionally, active magnetic levitation systems in rotor applications comprise separate motor for torque production, two or more radial active magnetic bearings (AMBs) and one axial AMB. Such an arrangement produces long rotors. Resulting AMB-rotor systems are often supercritical making the levitation control challenging. The centralization of the torque and force producing actuators shortens the...
Eccentric mass unbalance of the electric motor causes vibration of the shaft and the whole system, when the rotational speed increases. This paper considers rotation about an estimated center of inertia for a bearingless motor to reduce the vibration and power consumption for magnetic suspension. A 12-slot/10-pole bearingless SPM motor is selected for the performance test, because it has low suspension...
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 unbalanced magnetic force (UMF) occurs in permanent magnet (PM) machines when there is rotor eccentricity. This paper investigates the influence of slot/pole combination and magnet thickness on UMF in PM machines having different rotor eccentricities and magnetizations. It shows the machines with different magnetizations have different UMFs due to rotor eccentricity when magnet thickness and slot/pole...
In the paper the fractional order FID feedback control loop is designed in order to stabilize the unstable linear current-controller active magnetic bearing (AMB) system. The review for stability analysis of fractional continuous-time linear systems described by the transfer functions is given. The specified fractional order controllers, obtained for desired different phase margins, are verified by...
Active magnetic bearings (AMBs) provide a new proper solution to the high-performing rotating equipment. The active controlled electromagnetic forces of AMBs levitate the rotor without any contact with the stator. The advanced controller design is one of the hot issues associated with AMBs. This paper deals with the application of μ synthesis to the control of AMBs. The parametric uncertainty of the...
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)...
The self-sensing magnetic bearing technology offers significant cost savings and the potential for dynamics advantages due to its fundamental sensor-actuator collocation. This paper proposes a rotor displacement self-sensing scheme for the permanent magnet bias magnetic bearings (PMB) using three-level amplifier demodulation. Based on the proposed structure of radial PMB, the self-sensing principle...
The high-speed rotor supported by active magnetic bearings (AMBs) has been applied to air blower and gas compressor progressively for their advantages of high power density, low loss and small volume. In order to improve the modal of the multi-ring configuration rotor, the temperature gradient method was proposed. This method can reduce the axial gap width to increase the rotor stiffness and to further...
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...
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