Power electronic converters are extensively adopted for the solution of timely issues, such
as power quality improvement in industrial plants, energy management in hybrid electrical
systems, and control of electrical generators for renewables. Beside nonlinearity, this systems
are typically characterized by hard constraints on the control inputs, and sometimes
the state variables. In this respect, control laws able to handle input saturation are crucial
to formally characterize the systems stability and performance properties. From a practical
viewpoint, a proper saturation management allows to extend the systems transient
and steady-state operating ranges, improving their reliability and availability.
The main topic of this thesis concern saturated control methodologies, based on modern
approaches, applied to power electronics and electromechanical systems. The pursued
objective is to provide formal results under any saturation scenario, overcoming the
drawbacks of the classic solution commonly applied to cope with saturation of power converters,
and enhancing performance. For this purpose two main approaches are exploited
and extended to deal with power electronic applications: modern anti-windup strategies,
providing formal results and systematic design rules for the anti-windup compensator, devoted
to handle control saturation, and “one step” saturated feedback design techniques,
relying on a suitable characterization of the saturation nonlinearity and less conservative
extensions of standard absolute stability theory results.
The first part of the thesis is devoted to present and develop a novel general anti-windup
scheme, which is then specifically applied to a class of power converters adopted for power
quality enhancement in industrial plants. In the second part a polytopic differential inclusion
representation of saturation nonlinearity is presented and extended to deal with a
class of multiple input power converters, used to manage hybrid electrical energy sources.
The third part regards adaptive observers design for robust estimation of the parameters
required for high performance control of power systems