Ultra-Efficient Cascaded Buck-Boost Converter

This thesis presents various techniques to achieve ultra-high-efficiency for Cascaded-Buck-Boost converter. A rigorous loss model with component non linearity is developed and validated experimentally. An adaptive-switching-frequency control is discussed to optimize weighted efficiency. Some soft-switching techniques are discussed. A low-profile planar-nanocrystalline inductor is developed and various design aspects of core and copper design are discussed. Finite-element-method is used to examine and visualize the inductor design. By implementing the above, a peak efficiency of over 99.2 % is achieved with a power density of 6 kW/L and a maximum profile height of 7 mm is reported. This converter finds many applications because of its versatility: allowing bidirectional power flow and the ability to step-up or step-down voltages in either direction

A New Maximum Efficiency Point Tracking Technique For Digital Power Converter With Dual Parameters Control

This paper proposes a new maximum efficiency point tracking (MEPT) technique that will achieve the highest efficiency for DC-DC converters by automatically tracking converter efficiency while changing the switching frequency and dead-time control parameters. This new technique helps identify optimal values of each parameter at different power levels. In this paper, the developed MEPT technique is theoretically analyzed and practically verified. The experiment is set up based on a 120W Cascaded Buck-Boost converter, controlled by a centralized digital-signal processor (DSP). It will be shown that the expected theoretical and experimental results are in close agreement with each other