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This paper re-examines the basis for each eddy current stiffness term computed from prior published steady-state eddy current models. The paper corrects prior analysis work by confirming, through the use of 2-D and 3-D dynamic finite element analysis modelling, that when a magnetic source is moving over an infinite-wide and infinite-long conductive sheet guideway the steady-state lateral and translational stiffness terms will be zero and only the vertical coupled stiffness terms need to be modelled. Using these observations, a much simplified 6 degrees-of-freedom (DoF) linearized eddy current dynamic force model can be used to compute the steady-state force changes in eddy current based maglev vehicles when operating over a wide uniform conductive track.
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This paper used an analytic based 3-D second order vector potential model to study the vertical dynamic force ripple and dynamic airgap height change when using a one pole-pair electrodynamic wheel (EDW) maglev vehicle. A one-pole pair EDW creates the lowest lift specific power; however transient finite element analysis (FEA) also shows that the one pole-pair EDW will create a large oscillating vertical force when maintaining a static airgap height. A dynamically coupled eddy current model was used to confirm that when the airgap length is allowed to change with time then an increase in vertical airgap creates a large decrease in lift force thereby mitigating any large oscillatory airgap height changes from being created by the one pole-pair EDW. The small airgap height variation was exper-imentally confirmed by using a four-wheeled proof-of-principle radial EDW maglev vehicle.more » « less
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The rotation of an electrodynamic wheel (EDW) above a flat conductive, non-magnetic, track induces currents in the track that can create lift and thrust/braking force. This paper presents a new type of dual-EDW that consists of two EDWs in series that can also create a controllable lateral force. The magnitude and direction of the lateral force can be changed via the relative phase angle shifting of the two rotors. The changes in the lateral force magnitude as well as direction are shown to not affect the lift and thrust force magnitude. The geometric analysis of the design is presented and the practical difficulty of implementing the design is also discussed.more » « less
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This paper reports on the electromagnetic analysis and experimental testing of a newly invented six-degree of freedom electrodynamic wheel (EDW) magnetic levitation (maglev) vehicle that can stably levitate over a passive low-cost U-guideway. The U-guideway is composed of two sections of L-track aluminum sheet. Both a radial and an axial proof-of-principle EDW maglev vehicle has been built and experimentally tested. The EDW-maglev vehicle contains four one pole-pair diametric magnetized magnets that are driven using a low-cost motor and motor controller. No advanced controls are needed to provide basic stability. A 3-D transient finite element analysis model was used to study the 3-D forces created when the magnets are rotated over the aluminum L-track. The track design study showed that in addition to providing lateral recentering force the L-track can also be used to increases thrust and lift force.more » « less
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