RC08Brushless

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.

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)
  • [ ] Develope Model of Motor and get Frequency Response
  • [ ] 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

• NMOS and a PMOS
• The FETS have to be able to handle 10A drain current
• Matrix of Potential FETS Other FETs we considered

Schematics

Schematics

Parts

We are performing commutation on the FPGA with gate drivers.

FETS

Part No.	Make	Package	ContIDS	MaxIDS	Rds	MaxVGS	Samples	Data Sheet
NTMS4503N N-Channel	ON Semi	SO-8	14 A	--	--	28 V	Y	[1]
NTMS10P02 P-Channel	ON Semi	SO-8	10 A	--	--	20 V	Y	[2]

Articles

Modeling a DC motor Brush-Less Motor Simulink

Links

• Electrical System