msp430 motor controller applications

LT ThomasTJ Volinski

Pat O’HaraKole Reece

MSP430 Motor Controller Applications

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Outline

• H-Bridge• Types of Motors Polarity• Stepper Motor• Brushed Motor• Brushless Motor• Permanent Magnet Motor• AC Induction Motor

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Speed Controller

• Definition Closed Loop Vs Open Loop• How do we Implement motor control• Protection • Switching Mechanism– Bipolar Operation – Unipolar Operation

• Pulse Generator

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System Diagram

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Unipolar

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Bipolar

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Schematic Implementation

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Types Of Polarity

• Axial & Radial Flux

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Stepper Motors

• Introduced in the 1960’s• Replace Servos

• Advantages– Long Life– Excellent Low Speed– High Speed Protection

• Disadvantages– High Power– Big Size for Lower Power

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Robotgear.com

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Torque Control

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Motor Controller

• DRV88xx• Steps

• 8 to 45 Volts, 2.5 A

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MSP430 Applications

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Brushed DC Motor

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• Stator has permanent magnets• Rotor has coil, creates EMF• Half rotation is sensed with,

commutator. • Actually AC motor.

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Brushed DC Motor

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• 2 Brushes stillshort out

• Still have 4 loopsof conducting

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Brushless DC Motor

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• Coils on the Stator• Permanent Magnet on Rotor• Motor topology is

nondetermistic

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Brushless DC Motor

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• Add more phases to stator• Run current through different phases.

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Brushless DC Motor

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• Hall effect sensors detect transitions from North to South poles.

• 3 sensors provide binarydata. Never get 000or 111 therefore use aserror codes.

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Permanent Magnet Motor

• AC Motor• Sinusoidal Windings on Stator• 3-Phase: each winding coexists together

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Permanent Magnet Motor

• Field Oriented Control– Calculate the rotor flux– Calculate current of A,B,C windings to make current vector 90 degrees

of rotor flux.– Magnitude of current vector can be adjusted for different speeds

• Used in applications where a small motor is needed• Uses less power than other motors

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AC Induction Motor

• Rotor and Stator both have windings• Asynchronous Motor

– Magnetic field must rotate faster than rotor – Motor can slow down or slip

• Field Oriented Control or V/Hz– 16-bit microcontroller used for V/Hz– 32-bit microcontroller used for FOC

• Most popular motor in consumer and industrial applications

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MSP430 Brush and Brushless

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• MSP430 connected to a DRV8801 motorcontroller.

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Summary

• Low Speed with High accuracy– Stepper motor

• Long life– AC Induction, Stepper motor, & Brushless

• High Torque– AC Induction

• No Feedback– Stepper & Brushed

• Less Power– Permanent magnet

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QUESTIONS

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