Research on sectional constant slip control of linear induction motor based on parameter self-tuning

Linear induction motor (LIM) has the advantages of low noise, strong climbing ability and small turning radius. It is widely used in middle-low speed maglev traffic. However, in actual operation, the linear motor will weaken the thrust output due to the existence of the end effect which will lead to the reduction of the traction efficiency. At the same time, the fluctuation of normal force will disturb the suspension system and affect its suspension stability. To solve the above problems, this paper first establishes a LIM dynamic model considering the end effect, and proposes constant slip frequency vector control. According to the different requirements of normal force and thrust of the train in constant power and force area, the sectional constant slip control is carried out. Then an improved particle swarm optimization (IPSO) is introduced to optimize slip frequency at two stages to reduce the theoretically solved error of optimal slip frequency. Finally, the proposed algorithm is simulated and hardware-in-the-loop tests are carried out; The experimental results show that the proposed algorithm and improvements can meet the requirements of full speed thrust output and normal force of the train. It provides a certain reference value for traction control of the linear motor in middle-low speed maglev train.