Difference between revisions of "RC08Brushless"

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(Motor Controller Chip)
(MOSFET)
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====MOSFET====
 
====MOSFET====
 +
* '''See below for the parts to be used this year'''
 
* NMOS and a PMOS  
 
* NMOS and a PMOS  
* The FETS have to be able to handle 10A drain current
+
* The FETS have to be able to handle 10A on current
 
* [[RC08MotorFETS | Matrix of Potential FETS]] Other FETs we considered
 
* [[RC08MotorFETS | Matrix of Potential FETS]] Other FETs we considered
  

Revision as of 12:35, 6 March 2008

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 (Note: Already have design for motor drivers)
    • [X] Figure out max current draw. (10A starting current)
    • [X] Develop Model of Motor and get Frequency Response (Note: This is a task to be covered in firmware)
    • [X] Find and purchase Flat Flex Cable (FFC) connectors (Note: Found one)
    • [X] Purchase large mosfets for testing (Note: Test rig built and verified with drive motors)
    • [X] Purchase Surfboard for mounting DSC
    • [X] Build test rig
  • [X] Finalize on a DSC (Note: No DSC this year. Doing it in logic)
  • [X] Choose MOSFETS
  • [X] Sample all the parts
  • [X] Schematic Design
  • [ ] Build prototype
  • [ ] Prototype evaluation
    • [ ] Verify current draw under load especially start-up
    • [ ] Check if there is any temp rise in FETs in continuous operation
  • [ ] Make necessary changes

Specifications

Motor Controller Chip

  • Using an FPGA instead of a DSC
  • 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

  • See below for the parts to be used this year
  • NMOS and a PMOS
  • The FETS have to be able to handle 10A on current
  • Matrix of Potential FETS Other FETs we considered

Schematics

Parts

We are performing commutation on the FPGA with gate drivers.

Gate Driver

Microchip TC4428

  • 1.5 A
  • 6 mA quiescent
  • Noninverting low side
  • Inverting high side

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]

Motor Connector

Hirose FH12-11S-1SH 11 position 1 mm pitch

Commutation

CW (looking along the shaft toward the motor)

HS 1 HS 2 HS 3 Winding 1 Winding 2 Winding 3
1 0 1 Vcc Gnd n.c.
1 0 0 Vcc n.c. Gnd
1 1 0 n.c Vcc Gnd
0 1 0 Gnd Vcc n.c.
0 1 1 Gnd n.c. Vcc
0 0 1 n.c. Gnd Vcc

CCW (looking along the shaft toward the motor)

HS 1 HS 2 HS 3 Winding 1 Winding 2 Winding 3
1 0 1 Gnd Vcc n.c.
1 0 0 Gnd n.c. Vcc
1 1 0 n.c Gnd Vcc
0 1 0 Vcc Gnd n.c.
0 1 1 Vcc n.c. Gnd
0 0 1 n.c. Vcc Gnd

To find this data:

I duplicated the tables here because the text on the site is generated by Javascript, the frame URL contains a session ID, and the back button doesn't work.

Articles

Modeling a DC motor Brush-Less Motor Simulink

Links