Throttle control of BLDC motor

dekutree64 · July 19, 2025, 3:15pm

I had the same problem with back EMF spike just a couple days ago. I solved it by ramping the voltage limit, similar to PIDController’s output_ramp code. Perhaps we should move that code to its own class for easier reuse.

github.com/simplefoc/Arduino-FOC

src/common/pid.cpp

fb0be0748


      
          // Discrete derivation
          // u_dk = D(ek - ek_1)/Ts
          float derivative = D*(error - error_prev)/Ts;
          
          // sum all the components
          float output = proportional + integral + derivative;
          // antiwindup - limit the output variable
          output = _constrain(output, -limit, limit);
          
          // if output ramp defined
          if(output_ramp > 0){
              // limit the acceleration by ramping the output
              float output_rate = (output - output_prev)/Ts;
              if (output_rate > output_ramp)
                  output = output_prev + output_ramp*Ts;
              else if (output_rate < -output_ramp)
                  output = output_prev - output_ramp*Ts;
          }
          // saving for the next pass
          integral_prev = integral;
          output_prev = output;