A Chattering-Free Sliding Mode Control Method for Buck Converter

Abstract

The invention discloses a vibration-free sliding mode control method of a step-down converter, which belongs to the field of power electronic converters. Based on the average state model of the step-down converter, the present invention utilizes the second-order sliding mode control theory to design a chattering-free sliding mode controller for the step-down converter, adopting the fixed-frequency PWM mode, and changing the duty cycle of the switching device To control its turn-on or turn-off, and then realize the target voltage output of the step-down converter. At the same time, the overall scheme of the buck converter system under the action of the control method is realized based on the LabVIEW platform. The invention solves the chattering problem widely existing in traditional sliding mode control and the problems of slow response speed, low voltage output quality and poor anti-disturbance ability of the step-down converter controlled by the linear PID method. The control method utilizes its strong robustness, high steady-state precision and other advantages to overcome the disturbance influence of load resistance, DC input voltage, etc., and improve the performance of the output voltage.

Description

technical field [0001] The invention relates to the field of power electronic converters, and specifically utilizes second-order sliding mode control technology to eliminate chattering widely existing in traditional sliding mode control, and improve the dynamic performance and steady-state performance of the output voltage of a step-down converter. Background technique [0002] In recent years, due to the development of power electronics technology, buck converters have been widely used in various DC step-down applications, such as electric and hybrid vehicles, solar power generation, industrial instrumentation, portable electronic products and military aerospace and other fields. The main function of the step-down converter is to convert high-voltage direct current into low-voltage direct current and provide a stable direct-current voltage to the load. [0003] The power converter can be implemented either by a linear control method or by a nonlinear control method. As a t...

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Problems solved by technology

[0006] In order to solve the problems of chattering in the traditional sliding mode control method and slow response speed and weak anti-disturbance ability in the traditional linear PID control method, the present invention proposes a chattering-free buck converter based on second-order sliding mode technology. mode control method, and carry out digital realization, the present invention under the conditions of large disturbance, including start-up, load sudden change and input voltage sudden change, etc., utilizes second-order sliding mode control technology to design chattering-free sliding mode controller, and based on LabVIEW software Realize, improve the rapidity and stability of the output voltage of the buck converter

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