MSU ECE 4512 - Electric Motor for Challenge X

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Electric Motor for Challenge XMembersMotivationOverviewDesign ConstraintsConfigurationSlide 7TestingSlide 9Motor DesignSlide 11Slide 12Slide 13Controller DesignSlide 15Future WorkAcknowledgementsReferencesQuestions??Electric Motor Electric Motor for Challenge Xfor Challenge XMembersMembersFaculty AdvisorFaculty Advisor Dr. Marshall MolenDr. Marshall MolenTeam MembersTeam MembersMichael RobertsonMichael RobertsonCraig RossCraig RossDustin OttDustin Ott Jeff Smith Jeff Smith (Team leader)(Team leader)Hardware, testing, Website, simulation Hardware, testing, Hardware, Hardware, testing, Website, simulation Hardware, testing, Hardware, testing,testing, and research and research and research and researchand research and research and research and researchMotivationMotivationBecome involved in an effort to make Become involved in an effort to make vehicles cleaner and more efficientvehicles cleaner and more efficientGain experience in a large-scale Gain experience in a large-scale engineering effortengineering effortHelp MSU winHelp MSU winOverviewOverviewMany alternatives to a gasoline engine exist. In several lies a common thread:Electrical energy storage deviceElectrical energy storage deviceElectric motorElectric motorThe motor provides extra efficiency, high The motor provides extra efficiency, high starting torque, and the ability to starting torque, and the ability to recapture energy from the wheels.recapture energy from the wheels.Design ConstraintsDesign ConstraintsPowerPower90 – 110 hp90 – 110 hpMotor EfficiencyMotor Efficiency> 75%> 75%Generator Generator Must allow for for Must allow for for battery rechargingbattery rechargingStrengthStrengthMust handle high Must handle high starting torquestarting torqueSizeSizeMust fit in carMust fit in carWeightWeight< 800 lb< 800 lbConfigurationConfigurationOriginally, we considered 3 optionsOriginally, we considered 3 options1 AC induction motor1 AC induction motor2 AC induction motors2 AC induction motors1 AC induction + 1 DC permanent magnet motor1 AC induction + 1 DC permanent magnet motor1 AC induction motor seemed the best compromise 1 AC induction motor seemed the best compromise between performance and size / weightbetween performance and size / weightConfigurationConfigurationAnother option: 1 DC permanent magnet motorAnother option: 1 DC permanent magnet motorHigh energy densityHigh energy densityBetter speed controlBetter speed control> 90% efficient as both a motor and a generator> 90% efficient as both a motor and a generatorBrushed or brushless?Brushed or brushless?Brushless DC motors have longer lives, require less Brushless DC motors have longer lives, require less maintenance, and have better thermal / electrical / maintenance, and have better thermal / electrical / mechanical characteristicsmechanical characteristicsTestingTestingTo test the accuracy of the efficiency numbers, we To test the accuracy of the efficiency numbers, we decided to measure the characteristics of a smaller decided to measure the characteristics of a smaller brushless DC motor.brushless DC motor.Motor – Bosch Rexroth MKD-112C-058Motor – Bosch Rexroth MKD-112C-058Controller – Bosch Rexroth DKC01.3-100Controller – Bosch Rexroth DKC01.3-100Motor was operated via DriveTopMotor was operated via DriveTopMotoring characteristics were measured by placing Motoring characteristics were measured by placing various loads on the motorvarious loads on the motorTestingTestingResultsResultsMotoringMotoringMore testingMore testingneededneededGeneratingGeneratingWere not able to couple the MKD-112C with Were not able to couple the MKD-112C with another motor to test the generation another motor to test the generation capabilitiescapabilitiesTorque vs. Speed0123456781000 1200 1400 1600 1800 2000 2200 2400 2600 2800Spe e d (rpm )Torque (ft.lbs)Torque (ft.lbs)Motor DesignMotor DesignDimensionsDimensionsPower is proportional to l x rPower is proportional to l x r22 However, small r is essential for fitting under the However, small r is essential for fitting under the vehiclevehicleAlso, a long, thin motor would work better, Also, a long, thin motor would work better, mechanicallymechanicallyMotor DesignMotor DesignMaterialsMaterialsElectrically magnetized componentsElectrically magnetized componentsSimple field-weakening [1]Simple field-weakening [1]Permanent magnetPermanent magnetHigher torque, more compact [1]Higher torque, more compact [1]Magnetic compositesMagnetic compositesIncrease torque/weight ratio, decrease axial length [2]Increase torque/weight ratio, decrease axial length [2]Motor DesignMotor DesignFeedback [3]Feedback [3]Hall sensorsHall sensorsSimple controlSimple controlMore elaborate motorMore elaborate motorBack EMF sensingBack EMF sensingMore complex controlMore complex controlLess maintenanceLess maintenanceLess motor componentsLess motor componentsMotor DesignMotor DesignPossible modificationPossible modificationMultiple windings [4]Multiple windings [4]Two sets of windings with different numbers of Two sets of windings with different numbers of turns can act as an electric gear systemturns can act as an electric gear systemUseful for providingUseful for providing high starting torque high starting torque while retaining a while retaining a large region of large region of operation operationController DesignController DesignConcept [3]Concept [3]Two switchesTwo switches are closed at a are closed at a time timeThe rotor positionThe rotor position sensors are used to determine which two to activate sensors are used to determine which two to activatePulse widths determine the desired speed of thePulse widths determine the desired speed of the motor motorBack EMF zero-crossing can be translated to lookBack EMF zero-crossing can be translated to look like Hall sensor data like Hall sensor dataController DesignController DesignCommutation Algorithm [3]Commutation Algorithm [3] // If the state has not changed, do nothing// If the state has not changed, do nothing if (sensor_port = sensor_old) if (sensor_port = sensor_old) return return // Update the PWM outputs and retain the new state // Update the PWM outputs and retain the new state sensor_old sensor_old  sensor_port


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MSU ECE 4512 - Electric Motor for Challenge X

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