Design and optimization of the buck converter with the system identification method

Complex operations such as mathematical modeling are required to obtain the transfer function of a converter. At this point, system identification methods allow us to solve operations that require mathematical modeling very quickly and accurately. In this study, after designing an uncontrolled buck converter with MATLAB / Simulink application, a new modeling design based on the transfer function was aimed using the system identification method. The input and output values determined on the Simulink application are used as data inputs to determine the coefficients of the transfer function of the designed system. By using MATLAB System Definition Toolbox, different poles and zeros and coefficients were determined and transfer function models were proposed. The performance values of the proposed models are presented. The transfer function has been selected for the designed system. A PID controller has been added to the system to increase the stability of the uncontrolled system. For the optimization of PID control parameters, Ziegler-Nichols step response method, MATLAB 'PID Tuner' application and MATLAB 'pidtune' function were used and the performance values of these methods were compared. It has been shown that MATLAB applications give more successful results than the Ziegler-Nichols method, which is widely used in the literature. PID controller whose coefficients were determined with MATLAB 'PID Tuner' application was preferred for the system. The buck converter simulation circuit's uncontrolled and PID controlled open-loop and closed-loop performances are compared. When the circuit results were examined, it was seen that the transfer function extracted using the MATLAB system definition toolbox modeled the circuit quickly and accurately and simplified the controller design.