Robust adaptive backstepping controller design for PWM based DC-DC buck converter based on projection method

DC-DC power converter is a most important power source for driving a DC system in contemporary power electronic systems. However, owing to the time-varying and nonlinear characteristics of load resistance, it is often very challenging issue to ensure the stability of such converters. This paper is concerned about the regulation of the output voltage of a DC-DC buck converter using a nonlinear robust adaptive technique. The proposed controller is designed recursively based on the Lyapunov theory where the load resistance is considered as an unknown parameter. This unknown load resistance is estimated through the parameter adaptation law based on the projection method. Note that the projection method is a robustness augmentation technique that bounds the unknown parameter variations in a convex set which confirm through the formulation of control Lyapunov functions (CLFs) at different stages. The advantages of the proposed controller are that it can provide robust performance against external turbulence and also conquer the over-parameterization difficulty. At last the usefulness of the designed controller is verified through simulation results and compared with an existing controller. From the simulation results, it is obvious that the designed controller provides a significant performance improvement than the existing controller in terms of settling time and fast tracking desired output voltage.