Model based control of permanent magnet AC servo motor drives

This paper presents an innovative control law for permanent magnet synchronous motor (PMSM) drive for high dynamics applications. This kind of system (three-phase inverter connected with a PMSM) exhibits nonlinear behavior. Classically, to control the speed and the current (torque), a linearized technique is often used to study the stability and to select the controller parameters at specific operating point. In this paper, a model based control based on the flatness property of the drive system is proposed. Flatness provides a convenient framework for meeting a number of performance specifications on the PMSM drive. To validate the proposed method, a prototype PMSM drive (1 kW, 3000 rpm) is realized in the laboratory. The proposed control law is implemented by digital estimation in a dSPACE 1104 controller card. Experimental results demonstrate that the nonlinear differential flatness-based control provides improved speed/current regulation relative to a classical linear PI vector control method.