Control design for a quadratic buck converter with LC input filter

This paper models and proposes a controller for a modified quadratic buck converter where the input inductance has been replaced by an LC filter. The voltage conversion ratio of this converter is equivalent to two conventional buck converters in cascade and has only one active switching device. Due to the LC input filter, the high-frequency switching components are reduced at the input and this may entail even a time continuous input current as is shown in this paper. A controller is also proposed to regulate the output voltage to a given reference. Continuous input current is a requirement for sensitive electric power sources such as such as fuel cells, batteries and electrolytic capacitors used at DC-links in power electronics applications. The proposed controller provides damping to the closed-loop system. Numerical simulations are presented to evaluate the closed-loop performance.