Seite - 330 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 315 presentwhichobstructs thepathofmaximumcharging, theusermusthave theability to interrupt theoperationof theACAS.Therefore, theACASisdesignedso that theusercanenableordisable the operationof theACASatanytime,asshowninFigure6. Figure6.Blockdiagramof theACAS. 3.1.ACASSensorCoilUnit In theACAS, the rangeof lateralmisalignment is estimatedbasedonvoltage readings alone. Basedon(3), thevoltageonthe loadcoil canbeexpressedas follows: VL= jωM RL+ 1jωCL+ jωLL I1RL (6) Whenaconstantcurrentsource isbeingsuppliedto thesourcecoil, thedominantparameter that will changethe loadcoilvoltage isM.Toprove this statement,a3-DFEMsimulationwasconducted againusing the samemodel shown inFigure4andTable1, tomeasure the inducedvoltage in the loadcoil. TheresultsareshowninFigure7. It canbeseen in thegraphedtrends that thepeaksof the mutual inductanceandthe inducedvoltage in the loadcoil arenearly identical; thus, it showsthat the lateralmisalignmentcanbe identifiedthroughthe loadcoilvoltagealone. Figure7. 3-DFEMsimulationresult showingawaveformcomparisonof themutual inductanceand the inducedvoltageonthe loadcoil. Asmentioned in the introduction, themainchallenge is todeterminewhether the loadcoil is misalignedto the leftor theright side. Tosolve thisproblem,asensorcoilunit isproposed,which is composedof a single coil unitwoundaround themiddleof the leading sectionof the load coil, as illustrated inFigure8. With thisconfiguration, the loadcoil’s left/rightpositioncanbedeterminedbasedonthesource coil’s reference. Thesensorcoildoesnotoccupymuchspace,andthenumberof turns for thecoil is sufficient to induceasignal strongenoughfor theACASmaincontroller to recognize,while small enoughtonotdisrupt thepower transferbetweenthesourcecoilandthe loadcoil. 330