Chattering-free sliding mode control method for buck converter

Abstract

The invention discloses a chattering-free sliding mode control method for a buck converter, and belongs to the field of power electronic converters. The invention designs the chattering-free sliding mode control method for the buck converter by a second-order sliding mode control theory on the basis of an average state model of the buck converter. By a constant-frequency PWM mode, on or off is controlled by changing the duty ratio of a switching device, so that target voltage output of the buck converter is achieved. Meanwhile, the whole scheme of a buck converter system under the action of the control method is achieved on the basis of a LabVIEW platform. The widely existed chattering problem in traditional sliding mode control and the problems that a buck converter controlled by a linear PID method is low in response speed, low in voltage output quality, poor in anti-disturbance capability and the like are solved; and the control method overcomes disturbance influences of a load resistance, a DC input voltage and the like and improves the performance of an output voltage by the advantages of strong robustness, high steady accuracy and the like.

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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