Generalized Multivariable Grid-Forming Control Design for Power Converters

TL;DR

This paper introduces a unified multivariable feedback control framework for grid-forming converters, enhancing performance by simultaneously managing multiple power signals and employing $H_{ {infty}}$ synthesis for robust control design.

Contribution

It presents a generalized architecture unifying various control strategies into a multivariable feedback framework with simultaneous AC/DC and active/reactive power control.

Findings

Superior performance demonstrated in simulations and experiments.

Enhanced robustness compared to traditional control methods.

Effective handling of multiple error signals simultaneously.

Abstract

The grid-forming converter is an important unit in the future power system with more inverter-interfaced generators. However, improving its performance is still a key challenge. This paper proposes a generalized architecture of the grid-forming converter from the view of multivariable feedback control. As a result, many of the existing popular control strategies, i.e., droop control, power synchronization control, virtual synchronous generator control, matching control, dispatchable virtual oscillator control, and their improved forms are unified into a multivariable feedback control transfer matrix working on several linear and nonlinear error signals. Meanwhile, unlike the traditional assumptions of decoupling between AC and DC control, active power and reactive power control, the proposed configuration simultaneously takes all of them into consideration, which therefore can provide better performance. As an example, a new multi-input-multi-output-based grid-forming (MIMO-GFM) control is proposed based on the generalized configuration. To cope with the multivariable feedback, an optimal and structured $H_{\infty}$ synthesis is used to design the control parameters. At last, simulation and experimental results show superior performance and robustness of the proposed configuration and control.