Research on low speed control position observer for accumulator electric locomotive PMSM

Abstract

The PMSM of accumulator electric locomotive is generally controlled without position sensor, but the traditional position observer has the low speed observation accuracy, and the nonlinear factors of many mechanical parameters, such as torque feedback and moment of inertia, interfere with the low dynamic performance of the motor control system. A position observation model based on the nonlinear expansion observer is designed. The position observation model is constructed by using the relationship among the speed of the motor, the position angle of the rotor and its angular acceleration as well as the nonlinear function. Because it can avoid measuring the load torque and using the nonlinear expansion observer to estimate the uncertain disturbance, it is easy to realize. The simulation results show that the position observer can make the electric locomotive run stably under low speed control and has good low speed dynamic performance.