Towards the automatic tuning of MTPA algorithms for IPM motor drives

Energy saving is going to bias the next generation of electric drives, in all fields. Injection-based Maximum Torque per Ampere (MTPA) strategies are very appealing for their precision and robustness against parameter variations. Nevertheless, in the present literature, the tuning of the MTPA algorithm is still let to empirical practice, while the convergence issue is often presented from a rather intuitive point of view only. This paper lays the groundwork for a mathematical analysis of the MTPA convergence and, on these basis, gives some insights and useful hint for the automatic tuning of the algorithm. A novel proposal for the MTPA enabling under varying working conditions is also included.

I. Introduction

ENERGY saving is going to bias the next generation of electric drives, in all fields. Getting high performances while minimising drive losses requires special motors, with degrees of freedom in the torque production. To this aim, the internal permanent magnet synchronous motors (IPM) are a keen and appropriate choice. As the torque they produce has both electrodynamic and reluctance components, one can choose the combination that minimises the amplitude of the required current space vector for any given torque reference.