Quadratic programming in control of brushless motors

A new torque control strategy for brushless motors with minimum torque ripple and minimum copper losses while maintaining the phase currents under magnetic (or current) saturation is presented. The optimal control, a nonlinear map from desired torque and position to the motor's phase currents, is the closed form solution to a quadratic programming problem. Experimental results demonstrate virtually ripple-free torque and improved tracking accuracy. In case of magnetic or current saturation, the maximum torque capability of the motor is considerably increased.