5 Replies Latest reply on May 30, 2017 4:08 PM by epr_1639216

    Field Oriented Control CY8CKIT-037

      Hi. I am currently working on a high-voltage motor driver based on the motor evaluation kit CY8CKIT-037. Specifically, the bus voltage is 310V while the power output should be around 200W. I used the Pioneer kit CY8CKIT-042 as the control board, using the same pin assignments on the Arduino headers. I have implemented the Sensored BLDC on the modified driver board and now I am working on the Sensorless FOC. What changes on the firmware should I consider? I have read the Sensorless FOC application note and it seems that motor and hardware parameters are the only variables I can modify to reflect the high-voltage configuration of my driver board. Thanks for any help and/or advice

        • 1. Re: Field Oriented Control CY8CKIT-037
          EmHo_296241

          Hi,

          Are you using the example codes available with 037 kit ? What are your concerns ?

          • 2. Re: Field Oriented Control CY8CKIT-037

            Hi. Yes I am using the sample codes with some few modifications. For the Sensorless FOC sample code, I modified the motor parameters (line-to-line resistance, inductance etc) and the hardware parameters (resistor divider, bus voltage etc). The motor rotates during the open loop but it fails to enter the closed loop stage. I have checked the output of the current op amps and they are working properly. The motor is smoothly rotating in the open loop stage but then it starts to jitter and rotate in different directions after that.

            • 3. Re: Field Oriented Control CY8CKIT-037

              Keep in mind that with feedback control for the motor, it could potentially cause instability depending on your specific loop environment. (Basics of feedback control systems) I would suspect it is a case of instability causing the random jerks/motions.

              • 4. Re: Field Oriented Control CY8CKIT-037

                Is there a reference/certain equations or design guidelines in tuning the three PI controllers? I would like to have an idea how the values of the coefficients came to be in order to determine the effect of using a different motor on these coefficients. Thanks

                • 5. Re: Field Oriented Control CY8CKIT-037

                  Start with the Ziegler-Nichols method as a learning step, but there are more advanced techniques as well. Using google to look up the key searches: Feedback control, PID control, Ziegler Nichols should help you find articles for learning more about it.

                     

                  As a simplification, PID is: Proportional, Integral, Derivative, with each corresponding to Ax, B(integral of x), C(derivative of x)

                     

                  The coefficients are merely optimized/tuned for the specific system it is controlling, and hence you will probably need to test/check different values or calculate the optimal one using a Feedback Control Systems' method.