Direct torque control with an optimized observer for multi-machine systems

The first purpose of this work is to design a new observation technique for the Direct Torque Control (DTC). We put emphasis on robustness especially at very low speed, which represents the basic problem of the DTC operating, and on the optimization of the time computing. The reduced order observer is defined by decoupling the full order one in and axis. The second basic aim of this paper is to apply the DTC strategy to multi-machine multi-inverter industrial systems. Speed and tension controls are designed; their performances and parameter robustness are analyzed and compared with those obtained with a Flux Oriented Control (FOC). Mechanical and electrical couplings constitute the principal operation difficulty of these systems mainly when one of the machines is perturbed.