Effective current and speed controllers for permanent magnet machines: a survey

A survey is presented of the most interesting permanent-magnet DC and synchronous motor current and speed control structures. Which controllers can be chosen, how to tune them, and the performances that can be expected with analog or digital systems are discussed. Structures combining a feedback controller and disturbance and reference feedforward terms give good results and can be tuned as a whole (RST tuning processes). It is obvious that a compromise must be found between controller complexity (theoretical improvement of the performances) and controller realizability, for digital systems in particular.<>