General-Purpose Sliding-Mode Control Implementation Conclusions Switch-mode power supplies represent a particular class of variable structure systems (VSS), and they can take advantage of nonlinear control techniques | 8 Sliding-Mode Control of Switched-Mode Power Supplies Giorgio Spiazzi University of Padova Paolo Mattavelli University of Padova Introduction Introduction to Sliding-Mode Control Basics of Sliding-Mode Theory Existence Condition Hitting Conditions System Description in Sliding Mode Equivalent Control Stability Application of Sliding-Mode Control to DC-DC Converters Basic Principle Sliding-Mode Control of Buck DC-DC Converters Phase-Plane Description Selection of the Sliding Line Existence Condition Current Limitation Extension to Boost and Buck-Boost DC-DC Converters Stability Analysis Extension to Cuk and SEPIC DC-DC Converters Existence Condition Hitting Condition Stability Condition General-Purpose Sliding-Mode Control Implementation Conclusions Switch-mode power supplies represent a particular class of variable structure systems VSS and they can take advantage of nonlinear control techniques developed for this class of system. Sliding-mode control which is derived from variable structure system theory 1 2 extends the properties of hysteresis control to multivariable environments resulting in stability even for large supply and load variations good dynamic response and simple implementation. Some basic principles of sliding-mode control are first reviewed. Then the application of the slidingmode control technique to DC-DC converters is described. The application to buck converter is discussed in detail and some guidelines for the extension of this control technique to boost buck-boost Cuk and SEPIC converters are given. Finally to overcome some inherent drawbacks of sliding-mode control improvements like current limitation constant switching frequency and output voltage steady-state error cancellation are described. 2002 by CRC Press LLC Introduction Switch-mode power supplies SMPS are nonlinear and time-varying systems and thus the design of a high-performance control is usually a challenging issue. In fact control .
