Hybrid Control Method for Optimal Transient Response and Output Filter Minimization for Buck-Boost type Converters

This paper introduces a new digital control methodology for indirect energy transfer converters that is based on a hybrid controller concept. During transients, the control sets boundaries for inductor current and the output voltage based on the load conditions and the system requirements to facilitate rapid recovery and small output voltage variations. Once the output voltage is recovered, linear current programmed mode control operation is resumed. The control method significantly reduces the component stress requirements which leads to a smaller volume converter and can be realized on any digital current programmed mode control platform with very few additions. The operation of the controller was verified by simulation and experiments which found the new control scheme superior over the conventional linear control and time-optimal nonlinear control methods.