Is C2000 mController suitable for precise antenna tracking by BLDC??

Hello Andy!

Perhaps this thread will be useful for your issue http://e2e.ti.com/support/microcontrollers/c2000/f/171/p/279479/975473.aspx#975473

Regards,

Igor

Hi Igor,

thank you for reply. The link has clarified me some questions.

Regards,

Andy

Andrea,

Sure, C2000 could be used. I know several customers using for applications just like this, keeping locked on a satellite while the vehicle is in motion.

what sort of rotor sensors do you have available?  Hall or encoder?

you will be doing position control with an inner speed + torque loop (typically). For commutation you can use trapezoidal or sinusoidal/svpwm.  I see a lot of trapzoidal in these type of applications.

For the MCU there are many options, depending on architecture.  I've seen TMS320F28335 used to do 2 or 3 motors at a time. This is nice because the same MCU can do all of the coordinated motion between axis.

Another achitecture is to use as low cost MCU as possible like TMS320F28020 at each inverter/motor, and then coordinate between the two since you may already have another "big" processor in your system.

We also have InstaSPIN-MOTION, which we have used in pan tilt zoom applicatoins providing VERY impressive low speed smooth control. For this you would need to use TMS320F28068M device.

Hi Chris,

thank you for the answer and the hints.

About the rotor sensors we are still evaluating what type to use between hall and encoder. In a previous application I used BLDC motor with Hall Effect sensors, but I believe that when high stable rotor control is required is mandatory use encoders.

At this point I've a doubt:   in a previous antenna project I've used a dedicated embedded board to collect a IMU roll/pitch/yaw information to stabilize the antenna in closed loop. These IMU information were part of the input for the PID controller and the control chain was as following: 

IMU --> PID --> BLDC Controller --> BLDC Driver --> BLDC Motor

At these point my questions are:

1) can I use this kind of closed control loop with a C2000 Board (i.e. an evaluation kit)??

2) Is it possible to use the encoder of the BLDC together with an external closed loop information (such as IMU) to orient/stabilize the antenna when the car body is moving??

I think it is possible, but your opinion in this sense can confirm my thought.

Thank you in advance,

BR

Andy

How is the IMU board transmitting data to the PID controller? I don't really understand the feedback and logic that is required to eventually get to a control signal (position, speed, torque) for your motor.

Yes,at a minimum the C2000 board can run your PI controls and generate the BLDC control outputs. If we have the appropriate power level EVM for your motor it can create the Drive to apply voltage to your motor.

Hi Chris,

thanks for your support and sorry for delay to reply.

I attach two functional schemas (schema_1.png  and  schema_2.png ) to allow you to understand what I meant.

In the schema_1.png I develop a system with a SBC and an IMU to control the rotor position (closed loop by IMU information). A separated HW board was used to control the BLDC motor, but I don'tknow the impact of use an Encoder feedback instead of Hall Sensor. This solution was good, but now I want to delegate the control of BLDC motors into a dedicated HW Board with advanced control algos.

In the schema_2.png I'd like to use an IMU for the asset control closed loop  and a BLDC motor equipped with Encoder using a C2000 based board.

- In your opinion, is this solution possibile with a C2000 based board ?

- Will the Encoder information improve the rotor position accuracy/control respect the solution with only Hall Sensors take in mind that I've to manage little periodic oscillations around a reference point ?

I hope this helps to explain my doubts.

Thanks a lot again for availability and support.

BR,

Andy

- In your opinion, is this solution possibile with a C2000 based board ?

Yes

- Will the Encoder information improve the rotor position accuracy/control respect the solution with only Hall Sensors take in mind that I've to manage little periodic oscillations around a reference point ?

Yes, significantly improve rotor position accuracy.