Fixed-Time Synergetic Control of Multi-Interior Permanent Magnet Synchronous Motor Traction System With Dynamic Adhesion

The difference in wheel speeds within a train carriage arises from variations in traction motor performance and rail adhesion conditions. This can potentially lead to uneven wheel wear and, subsequently, to imbalanced traction and unstable train operation. To tackle this issue, this paper proposes a control method based on fixed-time synergetic control theory to synchronize the linear speeds of wheels in a multi-interior permanent magnet synchronous motor (IPMSM) traction system. The method considers load differences caused by wear differences between the front and rear wheels, as well as the dynamic adhesion conditions of the rail. First, the model of the permanent magnet synchronous traction system (PMSTS) is established by combining the single-axle train model with the dynamic model of the IPMSM. Then, synergetic control theory is extended with fixed-time theory to ensure the convergence performance of the PMSTS under any adhesion condition. Furthermore, a new synergetic load torque observer is designed to estimate the motor-side load torque, with the observed information used to track maximum adhesion coefficient. Finally, the proposed method is validated for its effectiveness and advantages through a hardware-in-the-loop platform.