Paralleling Induction Motor Traction System Coordination Control Study

With the rapid development of the high-speed railway technology, the traction drive system of high-speed train has the novel research tendency such as large power, small size,light weight, high reliability and low cost.The previous control strategies of single-induction motor can't meet the requirements of modern high-technology development in the field of the traction drive system of high speed train. Then the cooperative control of multi-induction motor comes into being. So the applications of advanced control theory in control strategy and control system of multi-induction motor have important realistic meaning and broad prospects.According to the traditional control method and the flux feedback control method for parallel-connected multi-motor,parallel-connected dual induction motors are taken as research object and the average speed of the system is estimated by pseudo-reduced order observer.And the vector control systems of parallel-connected dual induction motor are designed.At the same the simulations are finished on the condition of the different parameter of parallel-connected motors.The simulation results show that when the parameters of the parallel-connected motors are same,both control systems have good performance in dynamic state and stable state;when the parameters is different,the dynamic performance of both systems are bad;in the meantime,these control methods can't reflect the operation conditon of each motor.In the light of speed sensorless vector control of parallel-connected motors,the derivation proesses of the flux model and torque model of the parallel-connected dual induction motor traction system are given.According to the direct field orientation of single induction motor, the rotation transformation expressions of parallel-connected dual induction motor system are given. The Single induction motors is taken as research object,which speed is estimated by pseudo-reduced order observer.Vector control system of parallel-connected dual induction motor based on pseudo-reduced-order observer is designed.The simulations are carried out and compared with the traditional method.Simulation results show that the proposed method could reflect the running state of each mtor and identify the speed and load torque of each motor accurately.What's more,when the parameters of parallel-connected motors are different,the dynamic performance of the designed system is better than the traditonal one.