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Publication Date

Fall 2018

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)


Electrical Engineering


Mohamed Badawy


Cascaded buck-boost converter, Control of AC/DC converters, Control of DC/DC converters, Dual-Stage converters, Modeling of DC/DC converters, PFC circuits

Subject Areas

Electrical engineering


The focus of this research was on control strategies for dual-stage AC/DC converters used for power factor correction (PFC) applications. Since power conversion from AC to DC is a necessary step in most appliances such as mobile device chargers, appliances, and other devices, it is essential to maintain a high power factor operation to increase system efficiency. Hence, PFC circuits find a wide range of applications in AC/DC converters. The converters need a control structure to operate efficiently and provide the desired results. This thesis contributes two essential methods towards ongoing research on the control design of AC/DC converters for PFC circuits. First, the thesis presents a state space modeling approach to model dual-stage converters operating in a discontinuous conduction mode. Modeling is necessary to study the operation and performance of the converter. The converter model can be used to analytically develop control strategies. Second, this thesis presents an advanced control structure of a cascaded buck-boost converter for PFC applications. The proposed control structure operated the circuit at a unity power factor while lowering the current stress on the circuit components. The developed model and the proposed control structures used in the chosen AC/DC converter were validated by simulation results. Hardware design was developed to provide a setup that can be used to verify the simulation results experimentally.