Three-phase inverter backstepping sliding mode control method and system for achieving stabilization of micro-grid

Abstract

The invention discloses a three-phase inverter backstepping sliding mode control method and system for achieving the stabilization of a micro-grid, and the method comprises the steps: firstly taking filter capacitor voltage and inductor current as control variables, and building a mathematic model of an inverter system; secondly combining a backstepping method and a sliding mode variable structure method, and building a feedback control model of the inverter system; finally enabling the feedback control model of the inverter system to act on pulse width modulation, and carrying out the control of a three-phase inverter, thereby achieving the three-phase inverter backstepping sliding mode control for achieving the stabilization of the micro-grid. The method gives comprehensive consideration to the reality of the engineering application, is used for the three-phase inverter, is good in steady and dynamic characteristics, is very robust for the parameter perturbation and load disturbance, is suitable for linear, nonlinear and unbalance loads, can be popularized to other different types of three-phase inverters, provides an idea for designing an inverter control system, and is good in prospect of engineering application.

Description

technical field [0001] The invention belongs to the technical field of smart grids, in particular to a three-phase inverter reverse push sliding mode control method and system for realizing micro-grid stability. Background technique [0002] In recent years, microgrids integrating various distributed power systems and power electronic technologies have received more and more attention and research. By combining relatively mature distributed power supply technology, advanced control devices and various types of loads into a new power supply system, connecting it to the large power grid in the form of a micro-grid, and using flexible control strategies, the power supply capacity of the power grid can be improved. and power quality purposes. [0003] Power electronics technology is very important for distributed power supply to connect to microgrid, especially the inverter link, which is the final interface for many distributed power supply to connect to microgrid. The contro...

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Problems solved by technology

With the in-depth study of nonlinear control theory, the precise linearization method based on differential geometry theory has been widely used in inverters. However, this method is based on the precise mathematical model of the controlled object and does not consider the actual System uncertainty problem, so the robustness is not strong, the calculation expression is complicated, and the engineering realization is more difficult

h ∞ The performance of the control in anti-interference ability is superior, Chen Baoyuan et al. based on H ∞ Control theory designed the H of the single-phase voltage source inverter ∞ Output feedback controller, but the design process needs to solve the HJD (Hamilton-Jaccohi-Issaes) inequality. At present, there is no general solution method for the HJD inequality, and it is very difficult to obtain an accurate numerical solution. It often requires trial and error and certain design experience

Dong Fengbin et al. used the backstepping method to propose nonlinear feedback controllers for the three-phase voltage-type pulse width modulation inverter and the three-phase four-leg inverter respectively. The control performance of the proposed method is obviously better than that of the traditional PI control. However, there are the following problems in practical applications: ①The mathematical models of inverters are all based on accurate models, without considering the uncertainties existing in the actual system; ②The influence of external disturbances on control performance is not considered

[0006] From the above analysis, it can be seen that the existing technology for three-phase inverter control requires high accuracy of the mathematical model of the inverter system, and does not consider the influence of the uncertainty of actual system parameters and external interference on the control performance. The robustness is not strong, which does not meet the requirements of practical applications; the technology with strong anti-interference performance has a complicated calculation process, which requires trial and error, and engineering implementation is relatively difficult

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