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Energies 2017,10, 616
(b) Electromagnetic torque of motor in contrast model
(c) Rotary speed of motor
Figure6.Curvesofexpectedmotor torque,electromagnetic torque,andmotorspeed.
WeunderstandfromFigure6 that themotorrotaryspeedcouldsmoothlyandswiftly followthe
presetvalueandonlyhadaslightfluctuationat0.05swhenthe loadedtorque jumped. Switchingof
modeshadnoimpactonrotaryspeed. Electromagnetic torqueTe couldalso followexpectedtorqueT∗e
well. In thepresentcurrent followingaccuracy(h=3A), theamplitudeofelectromagnetic torque’s
fluctuationwas limitedwithin 5N·mor so, but after switching to lower voltage power source 2
asmajor power source, the fluctuationwasmore drastic, which indicated that setting the higher
voltagepowersourceas themajorpowersource ispreferable.Wealso foundthat themotorunder the
proposedmulti-level currenthysteresismodulationhadabout30%less torquefluctuationthanthe
motorunder traditional two-levelcurrenthysteresismodulation.
Windingmode, torquesaturation judgmental threshold Ith, andactual integration I curvesare
displayedinFigure7a,b.
InFigure7a, themodesignalsaredemonstrated: 1 is starmode,2stands for trianglemode,3and
4are the lowswitchingfrequencyandhighpowerdifferencemethods, respectively, in independent
mode, and 3.5 and 4.5 represented the flux-weakening region of the twomethods, respectively,
in independentmode. InFigure6a,b, twopeaksofexpectedtorquecurveat0.12sand0.17s indicate
thatwith increasing speed, voltage is almost saturated and electromagnetic torque cannot follow
expected torque, leading to the speed controller further increasing the expected torque; from the
electromagnetic torquecurve, it isevident that theactualelectromagnetic torquewillgraduallydecline
becauseofvoltagesaturationbefore theexpectedtorquepeak;whentorqueerroraccumulatesenough
tosatisfy torquesaturationconditions,upswitching is triggeredandelectromagnetic torquerapidly
follows the expected torque after switching; Fromelectromagnetic torque beingunable to follow
to the upswitching point, it only took 0.02 s. FromFigure 7b, we understand that 0.02 s before
upswitching,with thevoltagealmost saturated, theswitching integrationof torqueerror rosesharply
to the thresholdandupswitchingwas triggered.Afterwindingmodeswitching to trianglemodefrom
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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