Research on full-order sliding mode control method for Buck converter

Abstract

The Sliding Mode Control (SMC) system of DC converter is a kind of time-varying nonlinear system. There is a complex coupling relationship between the energy storage component capacitance and inductance, hysteresis modulation and SMC controller, which seriously restricts the transient response and output voltage quality of the system. In this paper, the full-order sliding mode control method is applied to solve the problems of differential seeking and high frequency chattering in the existing sliding mode control. For the second-order Buck converter system, a new full-step sliding surface and robust control law are designed, and the stability proof is given. The traditional sliding mode control chattering is caused by the symbol function in the control law. In the full-order sliding mode control, the switching control term uses the integral of the symbol function instead of the symbol function, and increases the order of the sliding mode variable to the symbol function. Integral derivation, on the basis of ensuring the control effect, the continuity of the control quantity is realized, the chattering is eliminated, and the full-order mode of the sliding mode motion of the Buck converter is guaranteed. System performance is improved by eliminating control amount chattering. By introducing full-order variable sliding mode control, the control amount of the Buck converter sliding mode control system is continuous, thereby eliminating the chattering of the control amount.