A sliding mode approach to control power sinks and power sources in dc-dc switching converters

Identifier:  TDX:4267

Handle: https://hdl.handle.net/20.500.11797/TDX4267

Authors:  Zambrano Prada, David Alejandro

Abstract:
The modeling of switched dc-dc converters as power elements used in photovoltaic systems, microgrids and electric vehicles. These models can appear in the form of single-port circuits, i.e., as a load or power source, or as two-port circuits. This is not only a formal approach, but is a design tool that in certain cases manages to ensure robust solutions than other alternatives.Constant power loads (CPL) appear naturally in the connection of cascaded converters or in the power train of electric vehicles when they operate simultaneously with constant torque and speed, where the motor demands constant mechanical power. These types of behaviors are particularly complex to control, due to their inherent open-loop instability. A range of proposals to deal with CPL has been found in the literature with proposals for linear controllers and nonlinear control methods. All these methods have in common some complexity in the (i) mathematical development of the control, (ii) in actual implementation of these controllers, (iii) in the need to measure several system variables, or in a combination of these. On the other hand, constant power demand to the load appears as a necessity in certain applications such as electric vehicle (EV) charging. A constant power-constant voltage charging protocol in ultrafast EV charging has reported relative advantages with the traditional constant current-constant voltage protocol. This opens the question of finding a way to deliver power to different types of load, generalizing the charging concept.