The Assessment of PI and Optimized OCC Control Methods in Buck Converter

Abstract

In Power Electronics sciences, DC-DC converters have a special place. The buck converter, which is a kind of them that decreases high-level voltage, is being used in many applications that need voltage level changes. One of the vital challenges is how to control converters with the highest working efficiency and the lowest cost, considering the dynamic behavior of the converter. In the last papers, various control methods were provided to control the converters and each had its advantages and disadvantages. The PI is one of the traditional control methods that had been used because of its comfortable analogue implementation and relatively good performance in eliminating systems error. The One Cycle Control (OCC) method is one of the newer control methods that has been much more successful in controlling the converters. One of the most critical features of this controller is detecting changes and perturbations of input voltage only during one switching period and rejecting them and also immediately following the reference voltage. In this research, in addition to the diode voltage, a feedback loop is also taken from the output voltage which is known as improved OCC method but the most advantages of presented method is the simplicity of structure and, consequently, reducing the cost of construction. So it can be called as optimized OCC. Due to the excellent dynamic behavior of the OCC control method, it is used as a controller in many sensitive industries such as instrument controls, navigation systems and so on. The primary purpose of this paper is to compare PI and optimized OCC methods applying to a buck converter. The simulation results in Simulink/MATLAB show the high speed of system response and the high sensitivity of the optimized OCC method indicate changes in buck converter. The practical implementation results, also has verified the simulation results.