Analysis of Damping Characteristics in Wind Turbine-Energy Storage Hybrid Systems Based on Path Module

Abstract

Current analytical methods are inadequate in uncovering the internal propagation mechanisms of disturbances and the interconnections between subsystems in the wind turbine-storage integrated grid connected system, which faces stability issues. Therefore, this paper employs a damping module modelling approach to conduct a dynamic analysis of the dynamic interactions in wind turbine-storage storage integrated systems, focusing on the damping path analysis with the phase-locked loop (PLL) as the oscillation mode. The research initiates with the linearisation of the doubly-fed induction generator (DFIG) and energy storage system (ESS) models. The closed-loop structure of the system is then presented to expose the disturbance propagation paths between subsystems. Subsequently, the damping coefficients of the second-order dynamic equation are expanded to include the dynamic equations of the most prominent oscillation mode, which establishes stability criteria for the system. Finally, by performing damping decomposition and reconstruction, the damping coefficients of each subsystem as well as the total damping coefficient of the interconnection system are obtained. An analysis is conducted on how the proportional-integral parameters of the PLL affect the damping of the interconnection system. The results suggest that the damping paths of the DFIG and the ESS can be expressed as a closed-loop structure diagram. By decreasing the proportional or integral coefficients of the PLL, the overall damping coefficient is increased, resulting in an enhancement of the stability of the grid-connected system.