PROJECT TITLE :

An Operating Condition-Based Scheme to Alternate Between Control Strategies for Improved Steady-State and Transient Behavior

ABSTRACT:

The control ways that use modulation techniques have nice acceptance in the present management of static power converters. Indeed, they offer a wide variety of alternatives to deal with the steady-state characteristics required by the system. Nevertheless, its computation and modulation delay negatively affects its dynamic performance. So as to improve the time response of the system, the modulator is avoided and therefore the methods of direct choice of the switching state have been presented. They can offer a very quick dynamic response; but, the absence of switching state sequences makes additional complicated the task of creating specific switching options for improved steady-state performance. During this work, a control scheme that selects a specific management strategy according to the operating condition of the system is proposed. This allows using modulators to satisfy the switching characteristics needed in steady-state and avoids its use when a rapid dynamic response is required. In addition, a soft transition method between the control strategies is presented to prevent unwanted behaviors when these are alternated. The proposed control theme permits simplifying the planning and keeps the main advantages of every selected strategy. To validate the theme, experimental results are obtained for a management structure that alternates between a finite set model predictive management (direct sort for rapid dynamic response) and a proportional integral (PI) control with sinusoidal pulse width modulation (SPWM) (modulated type for top steady-state performance).