Reference Stator Flux Linkage Calculation Method Using Local Search Algorithm for Maximum Efficiency Operation in Direct-Torque-Controlled PMSM Drives

A reference stator flux linkage calculation method is proposed for realizing maximum efficiency operation in direct torque controlled permanent magnet synchronous motor (PMSM) drives. A key feature of the proposed method is the ability to directly and successively search the optimal input power using a local search algorithm. Thus, the proposed method exhibits less dependency on the parameters of the PMSM compared to conventional parameter-based reference flux calculation method. Specially, the equivalent iron-loss resistance which is difficult to measure is not required. Simulation and experimental results validate the proposed method.