RC08Brushless

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In 2008 RoboCup switched to brushless DC motors. While brushless motors are smaller and far more efficient than brushed motors the commutation normally performed inside a brushed DC motor will need to be done externally using some control circuitry. There are two main parts to our brushless motor controller solution; the controller which uses sensors on the motor to gate signals to one of three coils, and the half-bridge motor drivers which actually drive the coils.For the controller a special-purpose brushless motor driver IC was used. For information on the motors or motor control software please see their respective pages.

Motor Frequency Analysis

Tasks

  • [ ] Get the motor and begin playing with it
    • [X] Call Maxon and get a recommendation on motor drivers (They spec parts not sure which drivers they use)
    • [X] Figure out max current draw. (10A starting current)
    • [ ] Find and purchase Flat Flex Cable (FFC) connectors
    • [ ] Purchase large mosfets for testing
    • [ ] Purchase Surfboard for mounting DSC
    • [ ] Build test rig
  • [ ] Finalize on a DSC
  • [ ] Choose MOSFETS
  • [ ] Sample all the parts
  • [ ] Schematic Design
  • [ ] Build prototype
  • [ ] Prototype evaluation
  • [ ] Make necessary changes

Specifications

Motor Controller Chip

  • The motor is spec'd at 12V and is 30W
  • A decent transient response (dead-time + switching time)
  • 3-Channels in one package
  • Braking is not a requirement but would be nice
  • High Impedance OFF state
  • Fault protection (overvoltage, overcurrent, fast response)
  • Small package
  • Ability to operate in the >20kHz range
  • Gate drive capability (either can directly driver the gate or is open drain.)
  • Data sheet recommends a MOSFET
  • Matrix of Potential Drivers

MOSFET

Schematics

Schematics

Parts

DSC

Quick Specs
Data Sheet

FETS

Quick Specs
Data Sheet

Articles

Thirty Second Filter Design

Links