the planetary motor
TRANSCRIPT
The Planetary MotorDesign and control of a
novel multi-rotor structure
Manfred SchrödlAndreas Brunner
Institute of Energy Systems and Electrical DrivesTechnische Universität Wien
A3PS Nov. 2017
Contents
• Deriving the topology of the Planetary Motor
• Electrical equivalent circuit
• Functional prototype
• Control strategy
• Sensorless INFORM® method
• Applications
• Future work
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The Planetary Motor
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• 3-phase motor• 3 single coils• 2-pole PM rotor
The Planetary Motor
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The Planetary Motor
• Arrange 4 equivalent motors symmetrically
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The Planetary Motor
• Combine into single structure
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The Planetary Motor
• Combine into single structure
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The Planetary Motor
• Areas of zero net flux
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The Planetary Motor
• Areas of zero net flux
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The Planetary Motor
• Rotors turn in opposite directions
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The Planetary Motor
• Rotors turn in opposite directions
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The Planetary Motor
• After 90deg: same areas with zero net flux
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The Planetary Motor
• Omit magnetically inactive parts:
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The Planetary Motor
• Corners are also magnetically inactive
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The Planetary Motor
• Corners are also magnetically inactive
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The Planetary Motor
• Corners are also magnetically inactive
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The Planetary Motor
• Corners are also magnetically inactive
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The Planetary Motor
• Omit magnetically inactive parts:
Reduced• Active mass• Motor volume• Iron losses
Same power as 4 combined single motors
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The Planetary Motor
• Combine coils
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The Planetary Motor
• Combine coils
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The Planetary Motor
• Combine coils: 12 coils 6 coils
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The Planetary Motor
• Integrated gear: sun gear
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The Planetary Motor
• Integrated gear: ring gear
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The Planetary Motor
• Integrated gear
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The Planetary Motor
• Integrated “planetary gear”• Sun gear and ring gear rotate at same speed
mechanical link for combined output power
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The Planetary Motor
• Integrated “planetary gear”• One point of contact for each gear (instead of two)• Gear ratios typ. 10:1
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The Planetary Motor
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The Planetary Motor
Conventional motor + spur gear
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R… gear ratiov … circumferential speed
The Planetary Motor
Integrated Planetary gear
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R… gear ratiov … circumferential speed
Electrical Circuit
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Electrical Circuit
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Original Circuit:
Electrical Circuit
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Electrical Circuit
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Reduced Circuit:
• 3-phase inverter• Star or delta connection
Functional Prototype
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Functional Prototype
• 4 rotors and 3-phase stator winding• 6 concentrated coils• Gear ratio 10:1• Sensorless control (INFORM / EMF)• Connection of all coils on the rear side of the motor
• Simple assembly
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Functional Prototype
Terminal voltages at 200rpm on output shaft:
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Control Strategy
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Control Strategy
• High-speed range (> 10% rated speed): EMF-method• Based on induced voltage• State of the art
• Low-speed range and standstill:INFORM® method• Based on inductance differences• Already used in series applications
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INFORM® Method
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INFORM-error:• mean 0.65deg• Standard deviation 6.01deg
(electrical)
/
Applications
• Electric vehicle axle drive• Integrated gear box• Hollow central motor shaft differential drive
• Wheel-hub motor
• Low speed / high torque
• Wind power
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PLANETARY MOTOR with differential gear D (housing T, bevel wheels K1, K2), functionallycombined with sun wheel Z1. Planets P1, P3 (shown without connected rotors of theelectrical part). Half axes A1, A2, connected todriving wheels
Future Work
• 4-pole rotors• 12 coils
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Future Work
6 rotors (series connection of 3 elements)
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Conclusion
• 1 rotor 4 rotors: half circumferential speed at same power
• Integrated transmission• Low speed / high torque applications
• Simple assembly• Concentrated coils• Integrated coil connections and power electronics on rear
side possible
• Standard 3-phase inverters• Sensorless control
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