Research On DC-DC Converter Stability Based On Switching Control System

The step-up and step-down DC-DC converter is an important link to ensure the stable operation of the photovoltaic DC grid,and its requirements for stability and dynamic performance are becoming higher and higher.Therefore,the step-up and step-down DC-DC converter has good performance.It has gradually become one of the mainstream research problems with practical value.The buck-boost DC-DC converter includes a boost mode and a buck mode.In order to avoid coupling between the two modes and cause system oscillation,a parallel structure is selected.In this paper,based on the theory of switching systems,the boost mode and the voltage mode are used as two subsystems to build a switching model,and the same Lyapunov function of the switching system is constructed to ensure that the switching system can operate stably under any switching,and operate according to the photovoltaic grid.The requirements of the pattern to design the switching law.First,adopt the Lyapunov function theory and Backstepping method to design the boost mode and buck mode sub-controllers,respectively,to ensure that the output voltage value of the DC-DC converter is always stable within the set constraints.Then,considering that the inductance and resistance in the actual DC-DC converter will fluctuate due to the influence of temperature and humidity,and it is not easy to accurately measure,so it is regarded as an uncertain parameter,and the system needs the output of the converter to be stable,so the Backstepping method and adaptive control technology are combined to design a nonlinear adaptive Backstepping controller to ensure that the DC-DC converter still outputs a stable voltage value under the condition of parameter disturbance,so that the state of the system has a faster convergence speed and operation.The process is also more stable.Finally,on this basis,the sliding mode technology is introduced to redesign the system with uncertain parameters.Class K functions are added to the design process,and an improved nonlinear adaptive sliding mode controller is designed.Furthermore,simulation experiments were carried out with the designed controller.The experimental results show that the designed controller has more obvious advantages in terms of stability performance,robustness,and convergence speed.The output of the controller is also closer to the expected value,the operation process is more stable,response and convergence is more faster.