Analysis and improvement of high efficiency and low cost drive system based on direct torque control

In this paper, an optimal reference stator flux strategy is proposed to improve the drive system efficiency under direct torque control (DTC). A novel low cost interior permanent magnet synchronous machine (IPMSM) is introduced and used. Based on the easily implementable loss model (LM), the controllable electrical losses which consist of copper loss and iron loss have been minimized under optimal stator flux. Based on finite element method (FEM), the harmonics which is produced by inverter is injected into FEM model; the nonlinear machine parameters and its influence to LMC are also considered. The drive performance´s effectiveness of the proposed scheme is validated in experiment.