Global Optimal MTPA Control of SynRM Considering Magnetic Saturation

Maximum torque per ampere (MTPA) control is widely used for synchronous reluctance motors (SynRMs) at low speeds to maximize efficiency. Considering the magnetic saturation effect, i.e., the inductance or flux parameters vary with the current operating point, determining the MTPA operating point requires the parameter information instantly extracted from the premeasured look-up tables (LuTs). However, the conventional method only determines the local optimal MTPA operating point related to the specific parameter information rather than the global optimal point. Therefore, this paper proposes a model-based online search method for global optimal MTPA. Firstly, the global optimal MTPA criterion is defined. Then, an iterative algorithm based on a finite current angle set is proposed to trade off the accuracy and computational burden of optimal operating point searching. The experimental comparison on a 3-kW SynRM platform verified the effectiveness of the proposed method.