A speed control of an interior permanent magnet motor drive ensuring minimum electrical loss

Nonlinear input-output linearization with decoupling concepts are used to effect a high performance speed control of the interior permanent magnet motor drives which also achieves the minimization of the electrical losses - the copper and core losses. This control scheme is unique in that saturation dependent parameters such as the d and q axis inductances and the voltage dependent core loss resistance are all included in the controller structure formulation and implementation. The proposed control scheme differs from known schemes which are either based on perturbation and search methods or on steady state fitted graphs that map the command q and d axis currents based on reference torques. Here, an optimization formulation that dynamically determines the reference currents/voltages required to achieve high performance speed control and total electrical loss minimization is used. The control structure methodology, the nature of the variations of the machine parameters and how they influence the machine efficiency and performance are clearly laid out in experimental and computer simulation results.