A Method for Selecting Inverter Sliding Mode Controller Coefficients

Abstract

The invention discloses a method for selecting the coefficients of an inverter sliding mode controller. Firstly, a phase variable model of a full-bridge inverter is established; then, combining the principle of sliding mode control and the working principle of an inverter, a switching function s is constructed, and the sliding mode is selected. Based on the modal control law uc, combined with the existence condition and reachability condition of the sliding mode, the existence condition of the sliding mode and the calculation formula of the boundary value of the sliding mode are derived; finally, the width of the hysteresis is determined. The present invention can directly use the formula to calculate the required sliding mode coefficient according to the expected design index and the known parameters of the main circuit; the design method of the sliding mode controller coefficient formula is simple and easy to operate; because the maximum overshoot is determined as the positive boundary of the sliding mode domain, when When the no-load jumps to full load, the designed sliding mode coefficient can ensure the rapidity and robustness of the inverter system response. The invention solves the problem that the sliding mode coefficient cannot be selected accurately, and directly establishes a relationship with the expected performance index of the inverter.

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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