Interconnection and damping assignment approach to control of PM synchronous motors

In this paper, we apply a recently developed energy-shaping controller desi gn technique to the speed regulation of permanent magnet synchronous motors . To illustrate different design choices, two controllers are presented alo ng with their stability analysis. The resulting schemes consist of a static state feedback to which a simple nonlinear observer is added to estimate t he unknown load torque. It is shown that, for isotropic rotor machines, we can set the tuning gains to recover a controller often used in industrial a pplications, where a nonlinear observer is used instead of a simple proport ional integral (PI) speed loop. Thus, the proposed scheme constitutes a pos sible upgrade to current practice which-in view of the availability of a co mplete stability analysis-should be easier to tune and yield improved perfo rmance. Simulations and experimental results are presented to illustrate th e performance of the proposed scheme.