Fast current trajectory tracking control based on synchronous optimal pulsewidth modulation

State-of-the-art pulsewidth modulation techniques fail to give satisfactory results when high-bandwidth torque control is required at the low switching frequency of modern high-power AC machine drives. A novel current control method refers to precalculated optimal synchronous pulse patterns. These are used to generate specific current reference trajectories to be adapted on line to the actual dynamic torque command. A fast tracking controller, operated in parallel to a conventional PI controller, minimizes the trajectory tracking error. The optimized current trajectories ensure fast response and minimum harmonic distortion