DA/DA buck ve boost dönüştürücülerin sınır kontrolünde doğal anahtarlamanın kullanılması

DC-DC converters are extensively used in many power electronics applications such as photovoltaic systems, wind energy systems, DC motor drives, mobile devices, electric vehicles, etc. Fundamental performance criteria in these applications include tight line and load regulation, low output voltage ripple, high efficiency and fast response to load uncertainties. Also, the trade-off between high performance and component sizes must be considered. In order to meet these requirements, a boundary control method is developed for the resistive loaded buck and boost DC-DC converters. First, normalized plant models are obtained for both converters. The normalization generalizes the controller design by making it independent of the circuit parameters. Then, natural phase plane trajectories of the systems are derived in the normalized domain. Using the natural trajectories of the converters as switching surfaces, special boundary control laws are defined. Switches in the systems are driven by control inputs generated according to the control laws. Via this boundary control method, the fast dynamic response is provided by utilizing passive components that take up the most space, namely inductor and capacitor, at their theoretical limits. This allows the overall circuit size to be kept small. Finally, the control laws are altered by a small factor so that in steady state, finite and controlled frequency operation and known ripple magnitudes of system states are obtained. In this way, a common problem in boundary control applications called chattering is eliminated. It is shown via simulations that the proposed controllers manage to recover from load and start-up transients by single switching action for both converters.