Nonlinear control of dc-dc switching converters with constant power load

Identifier:  TDX:2975

Handle: https://hdl.handle.net/20.500.11797/TDX2975

Authors:  Martínez Treviño, Blanca Areli

Abstract:
This thesis describes analytically the cascade connection of converters under constant power supply conditions, and propose simple control solutions that can cope with the potential instability caused by the constant power load (CPL). With this aim, the use of different strategies such as linear control, sliding-mode control (SMC), digital SMC (DSMC), and nonlinear PWM control is studied in the regulation of a boost converter supplying a CPL. The starting point is the analysis of the elementary converters in open-loop in the boundary between continuous conduction-mode (CCM) and discontinuous conduction-mode (DCM). Then, the SMC of a boost converter feeding a CPL is exhaustingly covered by a continuous-time approach leading to an analogue implementation. A discrete-time approach for sliding-mode control using a PWM resulting in a digital implementation is presented. Two analogue PWM-based nonlinear controllers as alternative solutions to regulate the output voltage in constant switching frequency operation are proposed. First, the use of a virtual mesh is developed to both stabilize the converter and indirectly regulate the output voltage. Then, a mechanism to estimate the power of the CPL is presented. Finally, the implementation of converters with CPL behavior by presenting a general systematic procedure of synthesis is addressed.