1. Introduction to Brush DC Motor Control
Making Them Stop
August 15, 2013 Paul Nickelsberg Orchid Technologies Engineering and Consulting, Inc.

2. Brush DC Motor Control Making Them Stop
Kinetic Energy
Resistive Braking
Active Braking
Back-EMF Protection
Regenerative Braking

3. Brush DC Motor Control Kinetic Energy
Motor is Spinning
Mass is Moving (Sled, Flywheel, Automotive)
Kinetic Energy = ½mv²
Kinetic Energy in Joules
Mass in Kilograms
Velocity in meters per second
Watts = Joules / Second

4. Brush DC Motor Control Kinetic Energy
200 lbs
90.9 kg
1.5 m/sec
Velocity
Velocity Profile
Position
1 Second
KE = ½mv² = ½ (90.9)(2.25) = Joules
= Watts (1 Sec Deceleration)

5. Brush DC Motor Control Resistive Braking
102.3 Watts?

6. Brush DC Motor Control Resistive Braking
Ohmite Data Sheet

7. Brush DC Motor Control Resistive Braking
IMS Datasheet

8. Brush DC Motor Control Resistive Braking
Caddok Datasheet

9. Brush DC Motor Control Active Braking
PWM
OFF
OFF
OFF
PWM ON
OFF
OFF
Braking
Free
Energy Flows through body diodes and into power source

10. Brush DC Motor Control Active Braking
200 lbs
90.9 kg
1.5 m/sec
Velocity
Velocity Profile
Position
Power Source Voltage
Elevated voltage
During deceleration
Position

11. Brush DC Motor Control Active Braking – Back EMF Clamp
Special Hi Power

12. Brush DC Motor Control Active Braking
200 lbs
90.9 kg
1.5 m/sec
Velocity
Velocity Profile
Position
Power Source Voltage
Elevated voltage
During deceleration - clamped
Position

13. Brush DC Motor Control Active Braking – Back EMF Clamp
resistor gets warm
Clamp FET
This is an N-Channel FET clamping from the low-side

14. Brush DC Motor Control Regenerative Braking
Power Source Voltage
Elevated voltage
During deceleration
Position
Charge Controller
Battery
Charge Controller Protects Battery from Overcharge
Component Parts Designed to Operate at Elevated Voltages

15. Introduction to Brush DC Motor Control
Join Us Tomorrow – Making Them Do Cool Things
Position Sensors
Microprocessor Control – QEI Block
Microprocessor Control – PWM Block
PI Control Algorithm
Constant Velocity Operation
Constant Position Operation