Design of Nonsingular Terminal Sliding Mode Controllers for DC-DC Power Converters based on a Particle Swarm Optimization

Abstract

This paper is focused on the development of a general approach to design Nonsingular Terminal Sliding Mode Controllers (NTSMC) for DC-DC Power Converters by considering some concepts of the Linear Sliding Mode Control with constant switching frequency in order to present two types of NTSM controllers. Thus, the main purpose of these controllers is to guarantee a finite time convergence avoiding singularities of the Terminal Sliding Mode Control as well as the asymptotical convergence of the Linear Sliding Mode Control and the infinite switching frequency which can damage the electronic components. Moreover, due to the lack of a method to select the coefficients of the NTSMC, a Particle Swarm Optimization (PSO) based on different Cost Functions is proposed to handle the proper selection of them. Finally, simulation results are presented to validate the performance of the proposed controllers with their coefficients optimized. In the case of the first NTSM controller, called Duty Cycle Controller, the best settling time obtained was about 3.56 milliseconds while with the second one, called Reaching Law Controller, the best settling time obtained was 3.34 milliseconds. On the other hand, both controllers maintain their stability in the presence of parameter variations such as load resistance or input voltage; however, the Reaching Law Controller exhibits the fastest response.