Paweł Dworak

This paper considers control of a grid-tied Wind Energy Conversion System (WECS) employing a variable-speed Permanent Magnet Synchronous Generator (PMSG). The system configuration consists of two back-to-back Voltage Source Converters (VSCs) for grid integration. Proportional-Integral (PI) controllers having limited control freedom are still favorable for such applications due to their simpler embedded realizations. To overcome the limitations of PI controllers, a Decentralized Dynamic Output Feedback (DDOF) controller that consists of a first-order dynamic compensator replacing the proportional term in the PI one while retaining the integral term is proposed in this paper. The controller is designed within a decentralized H_∞ framework exploiting the coupled dq-axis dynamics in both the machine-side and grid-side VSCs. The design incorporates regional pole-placement constraints to ensure desired damping and transient response characteristics, whereas the structural formulation preserves convexity, allowing different weighting specifications for individual subsystems to realize multiobjective performance. The resulting controller enhances disturbance rejection and robustness while maintaining a simple first-order plus integral control structure, which is suitable for real-time implementation on embedded processors. Experimental validation on a 5 HP laboratory-scale PMSG-based WECS demonstrates superior steady-state accuracy and transient performance compared to conventional PI and disturbance observer-based PI control, confirming the benefits of the proposed control approach.

This paper analyzes the problem of tension control in the processes of unwinding, rewinding, and winding materials, addressing how to implement such control in an open-loop system without the commonly used dancer rolls. It describes the theoretical and mathematical foundations of material tension control. An example problem of tension control on a real control object has been solved. An algorithm utilizing the torque control method in an open-loop system, which uses only servo drives to manage tension, is presented. This algorithm allows for increased process speed by unwinding two material rolls simultaneously, a capability that was not possible with single dancer roll control. Additionally, an algorithm for measuring the moment of inertia of material rolls using servo drives is discussed. The necessary measurements for the control algorithm to function effectively have been performed. The article concludes by presenting the results.

This paper deals with the problem of designing a dynamic decoupler for a class of two-inputs two-outputs nonlinear MIMO systems with experimentally modeled dynamics. The work describes the well-known linear theory of dynamic decoupling of TITO plants and discusses problems related to its application to nonlinear systems. The solution of constructing a fuzzy dynamic decoupler with two possible approaches is proposed. The paper gives a practical example of the synthesis of such a system for the air heater, which is an example of nonlinear thermal plant.