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Energies 2017,10, 616
Control strategiesofOW-PMSManddual invertershavealwaysbeenaresearchfocus.Winding
topologyandconfigurationsarewidelydiscussed inorder tooptimize themotor’sworkingrange
and efficiency [17–19]. Fault-tolerant operation [20–22] and zero-sequence voltage elimination
method [23,24] are alsounder extensive research. Loncarski, J. et al. compared theoutput current
rippleinsingleanddual invertermotordrivesforelectricvehicles,concludingthatthedual-2Linverter
canactasa3L inverterandoffersasignificant ripple reduction[2],whichcanalsobeobserved in this
paper.AnQun-tao,SunLietal. proposedadual invertersSVPWMmodulationmethodforcurrent
controlandin thiswayvoltagevectorsynthesized in therangeofahexagonandwhenthebusvoltage
remainsconstant, thebasespeedof theelectricmotorcouldbe1.7 times that inY-connectionwithout
generatingzero-sequencevoltage [7,8]. ZhanH.,HengN. et al. studieda commonDCbus-based
dual invertersSVPWMmodulationstrategy. In thisway, theamplitudeof thevoltagevectorcould
bemaximizedandat thesametimeazero-sequencecurrent couldbesuppressed [23,24].Welchko
studieddualsources-baseddual inverters’voltagevectorsdistribution,andproposedthree typesof
voltagedistributionmethodstoadapt todifferentworkingconditionsofhybridvehicles toachieve
energymanagement functionsbetween twopower sources [16]. However, the two inverterswork
independentlywithoutcoordination,andthustheswitchingfrequencyof inverterdeviceshasalso
doubled,which increases the inverterswitching loss.All thestudiesdiscussedabovehaveproposed
currentcontrolmethodsofdual invertersbutdivisionofOW-PMSMwindingmodesandwinding
modesswitchingarenot involved.NguyenN.K.etal. studieddual inverters-five-phaseOW-PMSM’s
windingmodes,dividedintothreetypes,starmode,pentagonmode,andpentaclemode,andanalyzed
theexternalmotorcharacteristicsofeachmode[18].However, thewindingmodesareonlydecided
basedonrotational speed.Adetailedwindingmodesswitchingmethodhasnotbeenproposed,nor
has there been an analysis of the energydistribution issue betweendual sources. Therefore, it is
necessarytoproposeacontrolmethodthatcouldmanageenergydistributionsbetweenpowersources,
andmakefulluseofeachwindingmode’sworkingrangetoreduce inverter lossandincreasesystem
efficiencyforelectricvehicles.
Thispaperfirstanalyzes the three-phaseOW-PMSMwindingmodesdivisionmethodandthe
externalmotorcharacteristicsofeachwindingmode.Onthatbasis,weproposea torquesaturation
windingmodesswitchingstrategy,which is insensitive tomotorparameters, toaccomplishautomatic
windingmodes switching according todifferentworking conditions. Then, amulti-level current
hysteresismodulationalgorithmused in independentmode isput forward. This algorithmcould
set themajorpowersourceandachievereal-timemajorpowersourceswitchingtodistributeenergy
betweentwopowersources. Inaddition,wedesigntwocontrolmethods: a lowswitchingfrequency
methodandahighpowerdifferencemethodfordifferentenergydistributionpurposes.At theend
of this paper, the feasibility and effectiveness of theproposedwindingmodes switching strategy
andmulti-level current hysteresismodulation are verified through simulations. Vehicle economy
performancesimulationalsoshowedthat theelectricvehicleunder theproposedcontrolmethodhas
betterefficiency.
Inparticular, coordinationtransformationsbetweenthe three-phasestatorandtwo-phaserotator
in thispaperwereequivalentpowerconversions.
2.WindingModeFeaturesAnalysisandSwitchingStrategy
ThedualsourcesOW-PMSMdrivesystemstructure is showninFigure1.
Accordingtodifferentwindingconnections, three-phaseOW-PMSMcanbedividedinto three
types: starmode, trianglemode, and independentmode. Starmode’swinding connection copies
traditionalPMSMs. It requiresheadsor tailsof three-phasestatorwindingsconnectedatonepoint.
If it isadual invertersconfiguration, it couldbecompletedbymakingeachbridge’s lowerarmturned
onsimultaneously in the idle inverter. Trianglemodeisaccomplishedthroughconnectingtheheads
andtailsof three-phasestatorwindings inacircle. Indual invertersconfiguration, it couldbeachieved
by shuttingdownonepower source and turningona triangle circuit switch. Independentmode,
243
Emerging Technologies for Electric and Hybrid Vehicles
- Title
- Emerging Technologies for Electric and Hybrid Vehicles
- Editor
- MDPI
- Location
- Basel
- Date
- 2017
- Language
- English
- License
- CC BY-NC-ND 4.0
- ISBN
- 978-3-03897-191-7
- Size
- 17.0 x 24.4 cm
- Pages
- 376
- Keywords
- electric vehicle, plug-in hybrid electric vehicle (PHEV), energy sources, energy management strategy, energy-storage system, charging technologies, control algorithms, battery, operating scenario, wireless power transfer (WPT)
- Category
- Technik