Grid-Forming Hybrid Angle Control: Behavior, Stability, Variants and Verification

TL;DR

This paper investigates the stability, behavior, and variants of grid-forming hybrid angle control (HAC), providing analytical insights and hardware-in-the-loop verification to enhance understanding and practical implementation of GFM converters.

Contribution

It offers a comprehensive analysis of GFM HAC, introduces variants, and validates performance through C-HiL testing, advancing the control strategies for grid-forming converters.

Findings

GFM HAC exhibits stable behavior similar to synchronous machines.

Variants of HAC improve robustness and adaptability.

C-HiL tests confirm effectiveness under real-world conditions.

Abstract

This work explores the stability, behavior, variants, and a controller-hardware-in-the-loop (C-HiL) verification of the recently proposed grid-forming (GFM) hybrid angle control (HAC). We revisit the foundation of GFM HAC, and highlight its behavioral properties in relation to the conventional synchronous machine (SM). Next, we introduce the required complementary controls to be combined with the HAC to realize a GFM behavior. The characterization of the analytical operating point and nonlinear energy-based stability analysis of a grid-connected converter under the HAC is presented. Further, we consider various output filter configurations and derive an approximation for the original control proposal. Moreover, we provide details on the integration of GFM HAC into a complex converter control architecture and introduce several variants of the standard HAC. Finally, the performance of GFM HAC is verified by several test scenarios in a C-HiL setup to test its behavior against real-world effect such as noise and delays.