Decoupling and delayed compensation method for complex vector PI controller of grid-connected converter

Abstract

The invention discloses a decoupling and delayed compensation method for a complex vector PI controller of a grid-connected converter. The decoupling and delayed compensation method comprises the steps of directly arranging a zero point of the controller at a pole point of a controlled object by taking a vector model of the controlled object as a basis to obtain a complex coefficient current controller model; calculating to obtain a system delay transfer function with regard to single delay of digital control and inherent zero-order maintaining characteristic of the converter; and achieving delay compensation of a current ring after connecting a delay compensation item in series with the complex vector PI controller. A single and effective method is designed for the current ring of the grid-connected converter, the problem of d-axis current and q-axis current coupling is prevented to the greatest extent, the phase margin of the system is expanded by delay compensation, the stability of the current ring is improved, and the dynamic response performance is improved.

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 such as 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 technology has attracted more and more attention. In a 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 role between the new energy power generation device and the power grid, and has become an import...

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