Grid-connected inverter controller bandwidth design method under weak power grid

Abstract

The invention discloses a bandwidth design method for a grid-connected inverter controller under a weak power grid and belongs to the field of power control. The bandwidth design method comprises the following steps of sampling, firstly giving a grid-connected inverter current control loop open-loop transfer function, then solving the amplitude of the current control loop open-loop transfer function, and finally giving a constraint relation between the current control loop bandwidth and the phase-locked loop bandwidth under a weak power grid by combining a Nyquist stability criterion, and parameter design of a current control loop and a phase-locked loop controller being completed. According to the method, the constraint relation and the value range of the design bandwidth of the current control loop and the bandwidth of the phase-locked loop under the weak power grid condition are quantitatively given, and a problem that a grid-connected inverter system is unstable due to interaction under the weak power grid condition can be effectively solved.

Description

technical field [0001] The invention relates to a bandwidth design method of a grid-connected inverter controller, in particular to a bandwidth design method of a grid-connected inverter controller under a weak grid, belonging to the field of electric power control. Background technique [0002] Since the 21st century, with the rapid development of various forms of power generation such as wind energy and solar energy, more and more renewable energy sources have been integrated into the large power grid through power electronic interfaces. Very weak network characteristics. The stability of the grid-connected inverter system under the weak grid is one of the most concerned and practically important issues in the stability research of the grid-connected interface system with power electronics. In an extremely weak grid system formed by a high proportion of power electronic grid-connected interfaces, the phase-locked loop and the control system usually interact to cause syste...

AI Technical Summary

Problems solved by technology

[0008] 1. When analyzing the stability of the grid-connected inverter system under a weak grid, many studies only qualitatively analyzed the influence of the grid strength and the interaction between the phase-locked loop and the current inner loop on the system stability, but did not give A specific method to solve the instability problem of the grid-connected inverter under the extremely weak grid

[0009] 2. When most studies solve the instability problem of the grid-connected inverter system caused by the interaction of controllers in weak grids, they only propose to design the bandwidth of the phase-locked loop to be small enough to avoid the control of the current loop as much as possible. Bandwidth, but the design range of PLL bandwidth is not given quantitatively, it needs trial and error and debugging

Images