Speed control of PMSMs with Interconnection and Damping Assignment or Feedback Linearization. Comments about their performance

The performance of interconnection and damping assignment strategy applied to speed control of permanent magnet synchronous motors is analyzed. It is noted that closed loop performance depends on interconnection and damping values injected by the controller. Certain designs produce nonlinear and coupled dynamics. When it is the case, the motor performance is degraded since direct current loop is adversely affected by the speed one. Then, from the nominal performance point of view some selections behave better than other ones. It is demonstrated that interconnection and damping assignment degrees of freedom can be used for improving the nominal performance. Interconnection assignment is calculated for constructing speed and direct current decoupled loops. In this case, tracking error dynamics becomes linear and its convergence speed can be adjusted by using the injected damping. Additionally, it is established that interconnection and damping assignment strategy attaining two decoupled tracking error dynamics loops results in feedback linearization.