Derivative-integral terminal sliding-mode control strategy for DC-DC buck converters

This paper presents a derivative-integral terminal sliding mode control (DI-TSMC) strategy for DC-DC buck converters. DI-TSMC is an extended version of integral terminal sliding mode control (I-TSMC) strategy which can be applied to systems with relative degree higher than one. Although, the buck converter with inductor current as the output is a relative one system, the ideal model buck converter with capacitance voltage as the output has relative two and therefore, I-TSMC cannot be applied to this model. When the inductor current is considered as the output, to implement the I-TSMC, it is required to estimate the desired value of inductor current. This can cause steady state errors in unexpected load variations. To overcome this problem, an ideal model of buck converter with capacitor voltage as the output is considered then DI-TSMC is applied to the model. It is shown that DI-TSMC exhibits superior performance during load changes through simulations.