Transcript MSP430 & Cortex Motor Driver

MSP430
Motor Controller Applications
Outline
•
•
•
•
•
•
•
H-Bridge
Types of Motors Polarity
Stepper Motor
Brushed Motor
Brushless Motor
Permanent Magnet Motor
AC Induction Motor
4/1/2011
2
Speed Controller
• Definition
Closed Loop Vs Open Loop
• How do we Implement motor control
• Protection
• Switching Mechanism
– Bipolar Operation
– Unipolar Operation
• Pulse Generator
2/16/2011
3
System Diagram
2/16/2011
4
Unipolar
2/16/2011
5
Bipolar
2/16/2011
6
Schematic Implementation
2/16/2011
7
Types Of Polarity
• Axial & Radial Flux
4/1/2011
8
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
Robotgear.com
4/1/2011
9
Torque Control
4/1/2011
10
4/1/2011
11
Motor Controller
• DRV88xx
• Steps
Full
1/2
1/4
1/8
1/16
1/32
• 8 to 45 Volts, 2.5 A
4/1/2011
12
MSP430 Applications
4/1/2011
13
Brushed DC Motor
• Stator has permanent magnets
• Rotor has coil, creates EMF
• Half rotation is sensed with,
commutator.
• Actually AC motor.
4/1/2011
14
Brushed DC Motor
• 2 Brushes still
short out
• Still have 4 loops
of conducting
4/1/2011
15
Brushless DC Motor
• Coils on the Stator
• Permanent Magnet on Rotor
• Motor topology is
nondetermistic
4/1/2011
16
Brushless DC Motor
• Add more phases to stator
• Run current through different phases.
4/1/2011
17
Brushless DC Motor
• Hall effect sensors detect
transitions from North to
South poles.
• 3 sensors provide binary
data. Never get 000
or 111 therefore use as
error codes.
4/1/2011
18
Permanent Magnet Motor
• AC Motor
• Sinusoidal Windings on Stator
• 3-Phase: each winding coexists together
4/1/2011
19
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
4/1/2011
20
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
4/1/2011
21
MSP430 Brush and Brushless
• MSP430 connected to a DRV8801 motor
controller.
4/1/2011
22
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
4/1/2011
23
QUESTIONS
4/1/2011
24