Method of selecting inverter sliding mode controller coefficient

Abstract

The invention discloses a method of selecting an inverter sliding mode controller coefficient. The method is characterized by firstly, establishing a phase variable model of a full bridge inverter; and then combining a sliding mode controlling principle and an inverter work principle to construct a switching function s and selecting a sliding mode control law uc; and combining an existence condition and an accessibility condition of a sliding mode to deduce the existence condition of the sliding mode and a boundary value calculating formula of the sliding mode; and finally determining a hysteresis band width. In the invention, according to an expected design index and a main circuit known parameter, the formula can be directly used to calculate a needed sliding mode coefficient; a sliding mode controller coefficient formula design method is simple and easy to operate; because a maximum overshoot is determined to be a sliding mode domain positive boundary, when a zero load is changed into a full load, the designed sliding mode coefficient can guarantee rapidity and robustness of an inversion system response. By using the method in the invention, a problem that the sliding mode coefficient can not be accurately selected is solved and connection is directly established with an inverter expectation performance index.

Description

technical field [0001] The invention belongs to the technical field of power frequency inverters, and in particular relates to a method for selecting coefficients of an inverter sliding mode controller. Background technique [0002] The power frequency inverter is an important grid-connected interface between distributed generation and modern power grids. Traditional PI-controlled inverters have poor dynamic characteristics and poor output voltage THD, making it difficult to meet real-time grid-connected requirements. Sliding mode control technology can overcome the shortcomings of traditional PI control technology and improve the transient performance and robustness of inverters with variable structure as the main feature. Therefore, the sliding mode control technology of inverters, especially the design of sliding mode controllers, is studied. method is practical. The application of sliding mode control to inverter systems can be traced back to 1990. So far, there have be...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for selecting the coefficients of the sliding mode controller of the inverter, aiming to solve the problem that the design method of the sliding mode controller coefficients in the existing inverter only provides a selection principle, and cannot provide a more accurate sliding mode coefficient problem

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