Reserch On Terminal Sliding Mode For Buck Convertor

The control technology of traditional Switching converter mostly is linear control technique. But conventional controller is more sensitive to the change of system parameters. When the converter input voltage or load changes on a large scale, the system response speed will become slow, waveform will get distorting and even the system would become instability. Variable structure, as a nonlinear control technology, is applicable for nonlinear natural characteristics of converter. The traditional variable structure control mostly adopts linear sliding surface. Once the system reaches the sliding surface, the tracking error will asymptotically converges to zero. To avoid the problem of asymptotic convergence and obtain better performance, terminal sliding mode control strategy is adopted in this paper.Firstly, we get the state equation of the converter using the averaged switch modeling method. Then, aimed at the control problem of the output voltage, an adaptive terminal sliding mode controller, based on RBF neural network to learn the uncertain up-bound value, is designed in order to improve the system performance and enhance the robustness. Next, aimed at the chattering of sliding mode control, an adaptive terminal controller without chattering is designed. This strategy can not only weaken the chattering, but also strengthen the robustness. At last, the conclusions are drawn, and the further research directions are presented.