Method for predictively controlling stability of large signal by inverter model based on Lyapunov criterion

Abstract

The invention discloses an inverter model prediction control large signal stability method based on a Lyapunov criterion. Comprising the following steps: performing Clark coordinate conversion on three-phase grid-connected voltage and three-phase grid-connected current of a grid-connected inverter to obtain a voltage component and a current component at an initial moment k under an alpha-beta coordinate; acquiring corresponding actual voltage vectors of the grid-connected inverter in different switching states within the sampling period at a set time interval; calculating a virtual voltage vector by using the actual voltage vector; forming a standby voltage vector set by using the virtual voltage vector and the actual voltage vector; calculating a predicted current value at the (k + 1) moment through the voltage component and the current component at the initial moment k and the voltage vector in the standby voltage vector set; inputting the predicted current value into a Lyaponov control function, and judging whether the predicted current value meets a stability requirement or not; and controlling the grid-connected inverter to be in the optimal on-off state. The system stability can be ensured, the current quality can be improved, and the grid-connected performance is improved.

Description

technical field [0001] The present disclosure generally relates to the technical field of three-phase two-level inverter control, and in particular relates to a large-signal stability method for inverter model predictive control based on Lyapunov criterion. Background technique [0002] Model Predictive Control (Model Predictive Control, MPC) is a computational control algorithm proposed in the 1970s, which has the advantages of simple and intuitive, easy to model, easy to add constraints, and strong robustness. Finite Control Set-Model Predictive Control (FCS-MPC) is an application category of model predictive control in power electronics, motor drives and other fields. The stability of FCS-MPC control system can be divided into small signal stability and large signal stability. The former can only guarantee the stability of the system near the working point, but cannot achieve the stability of large interference signals. [0003] However, there are still some problems in ...

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Problems solved by technology

The stability of the FCS-MPC control system can be divided into small signal stability and large signal stability. The former can only ensure the stability of the system near the working point, and cannot achieve the stability of large interference signals.

[0003] However, there are still some problems in the large-signal stability of the finite set model predictive control system based on the Lyapunov function method

First of all, due to the limited set of control vectors, the optimization strategy sometimes cannot find the control vector that satisfies the Lyapunov function; secondly, in most cases, the optimal vector or suboptimal vector that satisfies the Lyapunov function is not found in the model predictive control. Performance degradation, such as current quality degradation, or even distortion

Therefore, we propose a large-signal stability method for inverter model predictive control based on the Lyapunov criterion to solve the above-mentioned problem that the control vector is difficult to satisfy the Lyapunov function and the control performance is degraded

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