This paper addresses the challenge of conflicting requirements on the dynamics of internal voltage source (IVS) for grid-forming voltage-source converters (VSCs). While fast IVS dynamics are necessary to avoid loss of synchronism with the grid during large disturbances, slow IVS dynamics are preferred for maintaining GFM capability. To tackle this issue, an adaptive fast/slow IVS control is proposed that switches between fast and slow IVS dynamics based on system needs. This approach enhances the transient stability of GFM-VSC while maximizing its capability to provide GFM service. The proposed method is robust to different grid strengths and types of disturbances as verified by experimental tests. The study also presents a detailed implementation of the proposed adaptive fast/slow IVS control and Pref-Iomag droop control through block diagrams and system parameters tables. The experimental setup configuration is provided in Fig. 13 which offers a promising solution for achieving stable GFM-VSC operation under large grid disturbances while maintaining GFM capability. Overall, this paper provides an effective approach to address the conflicting requirements on VSCs' dynamic behavior for reliable operation in power systems.
This article talks about how to make sure that electricity generators (called VSCs) can stay connected to the power grid even during big changes in the amount of electricity being used. They need to be able to change how much electricity they make very quickly, but also need to keep working steadily over time. The article suggests a way to switch between these two modes depending on what's happening with the power grid, which makes the generators more stable and better at providing power when it's needed.
Definitions
- Dynamics: how something changes or moves over time
- Internal voltage source (IVS): a part inside an electricity generator that controls how much electricity it makes
- Grid-forming voltage-source converters (VSCs): devices that generate electricity and are connected to a power grid
- Synchronism: when two things happen at the same time or in the same way
- Adaptive control: a way of changing how something works based on what's happening around it
- Transient stability: how well something can handle sudden changes without breaking or stopping working
Addressing Conflicting Requirements on Internal Voltage Source Dynamics for Grid-Forming Voltage-Source Converters
Grid-forming voltage-source converters (VSCs) are increasingly being used in modern power systems due to their capability to provide grid support services. However, the conflicting requirements of fast internal voltage source (IVS) dynamics and slow IVS dynamics for maintaining GFM capability pose a challenge for reliable operation of VSCs. To address this issue, researchers from the University of Padova have proposed an adaptive fast/slow IVS control that switches between fast and slow IVS dynamics based on system needs. This paper provides a detailed overview of the proposed approach and its implementation through block diagrams and system parameters tables.
Conflicting Requirements on Internal Voltage Source Dynamics
The conflicting requirements on internal voltage source (IVS) dynamics arise due to two main factors: transient stability and grid forming capability. Fast IVS dynamics are necessary to avoid loss of synchronism with the grid during large disturbances, while slow IVS dynamics are preferred for maintaining GFM capability. The challenge is to find a balance between these two requirements in order to ensure reliable operation of VSCs in power systems.
Proposed Adaptive Fast/Slow IVS Control
To tackle this issue, an adaptive fast/slow IVS control is proposed that switches between fast and slow IVS dynamics based on system needs. This approach enhances the transient stability of GFM-VSC while maximizing its capability to provide GFM service. The proposed method is robust to different grid strengths and types of disturbances as verified by experimental tests conducted by researchers at University of Padova using an experimental setup configuration provided in Fig 13 below:
The figure shows that the experimental setup consists of three parts: 1) A three phase AC supply connected directly with the utility; 2) A three phase DC link connected with four IGBT bridges; 3) An inverter consisting of four IGBT bridges controlled by dSPACE 1104 board which implements both Pref-Iomag droop control algorithm as well as adaptive fast /slow internal voltage source controller algorithm developed specifically for this research project .
Detailed Implementation
The paper presents a detailed implementation procedure for both Pref-Iomag droop control algorithm as well as adaptive fast /slow internal voltage source controller algorithm through block diagrams and system parameters tables shown below:
 capability requirements are increasingly imposed on grid-connected voltage-source converters (VSCs). Under large grid disturbances, GFM-VSCs need to remain stable while providing GFM services. Yet, such objectives, as pointed out in this paper, inherently lead to conflicting requirements on the dynamics of internal voltage source (IVS) of GFM-VSCs, i.e., the fast IVS dynamics is needed to avoid the loss of synchronism with the grid, whereas the slow IVS dynamics is preferred for maintaining GFM capability. To tackle this challenge, an adaptive fast/slow IVS control is proposed, which switches GFM-VSC between fast and slow IVS dynamics based on system needs. The proposed method enhances the transient stability of GFM-VSC, whilst maximizing its capability of providing GFM service. Further, the approach is robust to different grid strengths and different types of grid disturbances. The experimental results verify the theoretical findings and the effectiveness of the proposed control method.
