Experimental Investigations of Minimum Power Consumption Optimal Control for Variable Speed AMB Rotor

Barbaraci, Gabriele; Pesch, Alexander H.; Sawicki, Jerzy T.

doi:10.1115/imece2010-40044

Cited by 10 publications

(10 citation statements)

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“…Another loss reduction can be achieved by reducing the control activity of the AMB [15]. Most of these strategies, like unbalance compensation (e.g., [16]) or a linear-quadratic-Gaussian-control (e.g., [17]), were not feasible at this point due to limitations of the AMB controller hardware. If no further loss reduction can be achieved in the components, the next step is to adjust the cycle time.…”

Section: Methodsmentioning

confidence: 99%

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

et al. 2019

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† This paper is an extended version of our paper published in: Franz, D.; Schneider, M.; Richter, M.; Rinderknecht, S. Magnetically levitated spindle for long term testing of fiber reinforced plastic.Abstract: This article discusses the critical thermal behavior of a magnetically levitated spindle for fatigue testing of cylinders made of fiber reinforced plastic. These cylinders represent the outer-rotor of a kinetic energy storage. The system operates under vacuum conditions. Hence, even small power losses in the rotor can lead to a high rotor temperature. To find the most effective way to keep the rotor temperature under a critical limit in the existing system, first, transient electromagnetic finite element simulations are evaluated for the active magnetic bearings and the electric machine. Using these simulations, the power losses of the active components in the rotor can be derived. Second, a finite element simulation characterizes the thermal behavior of the rotor. Using the power losses calculated in the electromagnetic simulation, the thermal simulation provides the temperature of the rotor. These results are compared with measurements from an experimental spindle. One effective way to reduce rotational losses without major changes in the hardware is to reduce the bias current of the magnetic bearings. Since this also changes the characteristics of the magnetic bearings, the dynamic behavior of the rotor is also considered. active and passive components. Active magnetic bearings (AMBs) are used for radial levitation and a passive magnetic bearing is used for axial levitation. A permanent magnet synchronous machine (PMSM) accelerates and decelerates the rotor. All rotating components of the magnetic bearings and the PMSM are integrated on the inner circumference of the FRP rotor. Under rotation, these components press against the FRP, resulting in radial compressive stress transversal to the fiber orientation, which is superimposed by circumferential stress in the fiber direction (see Figure 1b). The energy density of the system increases with the radii of the rotor and its rotational speed, both factors lead to an increased stress in the FRP [7]. Consequently, high stress in the material is necessary to reach high energy densities. Charging and discharging the flywheel leads to cyclically varying mechanical stresses. To investigate the cyclic stability and lifetime of the FRP rotor, cyclic material tests, such as cyclic transverse tensile tests (derived from [8]), cyclic transverse compressive tests (derived from [9]), and cyclic four-point bending tests are performed on material samples. These samples are thin walled and relatively easy to fabricate with a high quality, whereas the rotor of the flywheel is much thicker and harder to produce in an industrial fiber winding process. Furthermore, the thermal expansion of carbon fiber and the epoxy plastic matrix used differ, leading to inner stress when a thick walled FRP structure cools down from the curing temperature. Hence, there is a much higher probabi...

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Section: Methodsmentioning

confidence: 99%

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

et al. 2019

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“…The magnetic force (9a)-(9d) produced by an electromagnet of active magnetic bearing is linearized by Taylor series expansion which leads to the expression of the force (9a), [5]:…”

Section: Mathematical Modelmentioning

confidence: 99%

“…During last twenty years, a fast number of control systems were applied on magnetic levitation in order to provide enough acknowledge about the capability of rotor to maintain the contactless between the rotor and stator. Obviously while there are many control systems which are not able to maintain the operating point position of the controlled sections without a further algorithm such as the integrator of a PID controller [5], some other control systems need the entire state vector to create the feedback such as the optimal control [3] characterized by a matrix whose number of column is equal to the dimension of state vector. The cutting edge of control systems is represented by μ-synthesis, loop-shaping design procedure, and H-infinity robust control, the latter with its variant sub(H) ∞ .…”

Section: Introductionmentioning

confidence: 99%

Performances Comparison for a Rotating Shaft Suspended by 4‐Axis Radial Active Magnetic Bearings via μ‐Synthesis, Loop‐Shaping Design, and Sub(H)_∞with Uncertainties

Barbaraci

Mariotti

2011

Modelling and Simulation in Engineering

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The control systems applied on active magnetic bearing are several. A perfect levitation is characterized by maintaining the operating point condition that is characterized by the center of stator coincident with the geometric center of shaft. The first controller implemented for this purpose is PID controller that is characterized by an algorithm that leads the amplifier to produce control current until the operating point condition is not reached, this is obtained by an integration operator. The effect of an integrator is essential but not necessary for a centered levitation for example in the robust control characterized by a dynamic model depended on plant of system so that it depends on angular speed as LQR controller does. In LQR there is not integrator so there is not a perfectly centered section of shaft with center of stator. On contrary PID controller does not depend on angular speed and it can be easily implemented according some simple rules. Predictive control is another interesting controller characterized by a multiple controller operating in different condition in order to get the minimum of cost function, but also in this case the angular speed is introduce for the same reason discussed before.

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“…Obviously no levitation would be stable without a control system (Schweitzer and Maslen, 2009;Barbaraci et al, 2010). Barbaraci and Virzi' Mariotti (2012) analyze the influence of optimal design on magnetic line pattern.…”

Section: Introductionmentioning

confidence: 98%

Active magnetic bearing design study

Barbaraci

Mariotti

Piscopo

2012

Journal of Vibration and Control

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The purpose of this paper is to propose a useful method to implement active magnetic bearings (AMBs) on an existing\ud rotating shaft which rotates on conventional bearings. This is feasible if AMBs can produce the same reaction loads of\ud conventional ones and if the size of vane is large enough to host an AMB. As this substitution could offer some difficulties\ud due to the different size between magnetic bearings and conventional ones, a set of equations are performed to show\ud that a variation of some parameters can solve this problem. The journal ratio is the geometrical parameter introduced to\ud develop the present analysis. The variation of journal ratio does not produce a variation of the pole’s surface so that the\ud reaction load does not change. The results are analyzed by numerical analysis by mathematical relationships involving the\ud design parameters, magneto-static simulations and dynamic simulation on shaft when it is tested by disturbance rejection\ud and reference tracking input in order to analyze the differences on dynamic behavior of the shaft on its suspended\ud sections. Results show that the displacement pattern of the suspended sections remains unchanged, confirming that the\ud reaction load, produced by pole expansion, remains the same varying the journal ratio

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Experimental Investigations of Minimum Power Consumption Optimal Control for Variable Speed AMB Rotor

Cited by 10 publications

References 0 publications

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

Performances Comparison for a Rotating Shaft Suspended by 4‐Axis Radial Active Magnetic Bearings via μ‐Synthesis, Loop‐Shaping Design, and Sub(H)_∞with Uncertainties

Active magnetic bearing design study

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Experimental Investigations of Minimum Power Consumption Optimal Control for Variable Speed AMB Rotor

Cited by 10 publications

References 0 publications

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

Thermal Behavior of a Magnetically Levitated Spindle for Fatigue Testing of Fiber Reinforced Plastic

Performances Comparison for a Rotating Shaft Suspended by 4‐Axis Radial Active Magnetic Bearings via μ‐Synthesis, Loop‐Shaping Design, and Sub(H)∞with Uncertainties

Active magnetic bearing design study

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Product

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Performances Comparison for a Rotating Shaft Suspended by 4‐Axis Radial Active Magnetic Bearings via μ‐Synthesis, Loop‐Shaping Design, and Sub(H)_∞with Uncertainties