Decoupling and delay compensation method of complex vector pi controller for grid-connected converter

Abstract

The invention discloses a complex vector PI controller decoupling and delay compensation method of a grid-connected converter. Based on the vector model of the controlled object, the zero point of the controller is directly set at the pole of the controlled object to obtain Complex coefficient current controller model; for the one-shot delay of digital control and the inherent zero-order hold characteristic of the converter, the system delay transfer function is calculated, and the current loop is realized by connecting the delay compensation item in series after the complex vector PI controller delay compensation. The invention provides a simple and effective method for the current loop design of the grid-connected converter, suppresses the current coupling problem of d and q axes of the current loop to the greatest extent, increases the phase angle margin of the system through delay compensation, and improves the current Ring stability and improved dynamic response performance.

Description

technical field [0001] The invention belongs to the technical field of converter current control, in particular to a method for decoupling and delay compensation of a complex vector PI controller of a grid-connected converter. Background technique [0002] With the increasingly serious problems of energy shortage and environmental pollution, the development and utilization of new energy sources such as solar and wind energy are accelerating, and new distributed power generation technologies have attracted more and more attention. In the distributed grid-connected power generation system, most of the electric energy generated by the energy conversion device must be converted into alternating current with the same frequency and phase as the grid voltage through the grid-connected converter before it can be fed into the grid. The grid-connected converter plays an essential interface between the new energy power generation device and the grid, and becomes an important part of th...

AI Technical Summary

Problems solved by technology

However, for high-performance controllers, the delay cannot be ignored after all, especially when the control frequency is higher than the switching frequency, the delay will affect the feedback decoupling. In addition, the grid-connected inductance parameters vary with temperature The change of will change, resulting in inaccurate feedback decoupling items, affecting the control performance of the current loop, so it is necessary to study the decoupling and delay of the current loop

Images