Fuzzy self-adaptive sliding-mode control method of single-phase photovoltaic grid-connected inverter

Abstract

The invention discloses a fuzzy self-adaptive sliding-mode control method of a single-phase photovoltaic grid-connected inverter. The fuzzy self-adaptive sliding-mode control method is characterized by comprising the following steps of 1, building a photovoltaic inverter mathematical model considering system structural parameter uncertainty and an external disturbance item; 2, designing a sliding-mode controller; 3, designing a fuzzy self-adaptive sliding-mode controller; and 4, controlling a photovoltaic system according to output of the sliding-mode controller and the fuzzy self-adaptive sliding-mode controller. By the fuzzy self-adaptive sliding-mode control method, an accurate mathematical model of the photovoltaic system is not needed to build, a controlled objected is approached by fuzzy self-adaptive control, so that the system structural parameter uncertainty and the external disturbance item are considered; the control rate is designed according to voltage deviation by sliding-mode control, so that control has robustness, and the requirements of stability and robustness can be met; and when a system environment is abruptly changed, a control algorithm can reliably work, and the single-phase photovoltaic system outputs stable sine AC voltage.

Description

technical field [0001] The invention relates to a fuzzy self-adaptive sliding mode control method of a single-phase photovoltaic grid-connected inverter. Background technique [0002] With the depletion of fossil energy and human demand for clean energy, photovoltaic system grid-connected power generation technology has developed rapidly in recent years. However, photovoltaic power generation itself is unstable and intermittent, and its grid-connected power quality and power generation efficiency are affected Due to the influence of various factors such as the external environment state, the uncertainty of system structure parameters, and external disturbances, an effective inverter control algorithm is the key to solving the grid-connected problem of photovoltaic systems. [0003] Existing small photovoltaic grid-connected systems usually adopt a two-stage high-frequency topology without an isolation transformer: that is, the front stage uses a Boost circuit to realize DC-D...

AI Technical Summary

Problems solved by technology

It uses the maximum power point tracking (MPPT) control in the Boost circuit to improve the power generation capacity. However, when controlling the inverter, it is necessary to establish an accurate mathematical model of the photovoltaic system, which cannot take into account the uncertainty of system parameters and external disturbances. , poor control stability and robustness

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