Perturb and Observe based Online MTPA of PM Assisted SynRM for Traction Application

Maximum torque per ampere (MTPA) control is necessary for achieving highest possible operational efficiency of a permanent magnet assisted synchronous reluctance motor (PMA-SynRM). However, large degree of parameter variation in these motors due to core saturation, elevated temperature and age makes it very difficult to implement a theoretical rule based MTPA that can achieve an acceptable degree of accuracy. Automatic MTPA approaches proposed till now present problems of increased computational intensity and requirement of extensive testing before control design. This paper attempts to address these issues by proposing a perturb and observe based online MTPA approach that is computationally simple and compensates parameter uncertainties automatically. Detailed simulation results are discussed to validate the accuracy of its MTPA trajectory and dynamic performance.