Direct torque control for permanent magnet synchronous motor based on inverse system decouple theory

A inverse system decouple control strategy for DTC- PMSM was proposed based on the nonlinear PMSM mathematical model in stator coordinate frame with the output variables of torque and stator flux linkage amplitude,and the inverse conditions for different types of PMSM were discussed. With the help of inverse system theory,the nonlinear DTC- PMSM system was decoupled into two independent one- order subsystems of torque and stator flux linkage,and two PI closed- loop controllers for torque and stator flux linkage were applied to achieve dynamic decoupling between torque and flux linkage. The experimental results show that the novel PMSM- DTC drive has very good dynamic and steady- state performance.