Distributed internal model control for speed synchronization of multiple PMSMs in urban rail traction systems

As a popular traction motor in urban rail transit (URT), permanent magnet synchronous motor (PMSM) is subject to load torque disturbance and parametric uncertainties. Thus it is challenging to achieve high-precision speed synchronization of multiple PMSMs especially when communication constraints are taken into account. This paper proposes a distributed internal model control approach to tackle the speed synchronization control problem of multiple PMSMs in URT under directed communication network and parametric uncertainties. In particular, we first formulate this problem as a cooperative robust output regulation (CROR) problem. By constructing an appropriate distributed internal model, the CROR problem is transformed into a robust stabilization problem of an augmented multi-agent system (MAS). Then a stabilization controller is designed to stabilize this augmented MAS. Both the simulation and experimental results validate the effectiveness of the proposed control method.