About this Research Topic
The electrical grid is rapidly changing from a mature electro-mechanical system that has enjoyed well established knowledge for more than 80 years into a power electronics dominated system that is changing its nature in fundamental ways. In the near future the electrical grid will be a system composed of a large number of widely distributed small power sources and loads, each interfaced by some kind of power electronics converter, which is essentially non-linear in nature and will often operate in a non-sinusoidal and unbalanced regime. In this new electrical system, energy will be exchanged between numerous wind farms, photo-voltaic (PV) power parks, wave energy parks, biogas power generators, batteries and other forms of active loads, where the Voltage Source Converter (VSC) will be a fundamental component. In this context, the complex dynamics and broadband control of VSCs can cause inadvertent system interactions leading to instability. VSCs interacting in electric power systems is an example of an interacting electrical dynamical system, whose nonlinear dynamic behavior concerning synchronization remains not fully understood.
Recently, there has been significant interest and developments in the study of interactions and synchronization in power electronics dominated systems, indicating the crucial role of synchronization on the system stability. The state of synchronization should be robust since it is an underlying condition for the stable operation of electric power grids. Understanding synchronization and interaction mechanisms is important for the electrical network to be highly controllable in order to ensure a stable delivery of power. Field experience in wind farms, PV power parks and marine vessels has shown that ensuring stable operation of this new system with widely distributed small sources can be a major challenge. Conventional stability analysis methods cannot always explain all oscillatory behavior observed in the field and often it is not in the nature of the individual component, but how they interact that determines their collective behavior. Current grid models and stability analysis methods present either (1) a large-scale abstract model characterizing power flows, static and probabilistic features or (2) detailed, component-level models of engineering used for specific simulations. The first approach is limited to statistical information while the second restricts general insights about dynamics on large scales. We need new methods to tackle problems associated with synchronization and interactions in complex network structure. These questions are intimately related to the stability of the system and will play an important role in practical applications of various electrical grids (microgrids, wind, PV, wave energy conversion systems, marine vessels).
This Research Topic requires multi- and inter-disciplinary efforts, welcoming contributions from researchers working on several related fields, not only Power Electronics, but also Nonlinear Dynamics of Complex Systems, Dynamics of Coupled Oscillators, and Self-organized Synchronization. We expect this Research Topic to bring together engineering expertise and experience on the behaviour of power electronics systems with expertise on the dynamics of nonlinear oscillator networks. We seek contributions that can shed light on the fundamental mechanisms of interaction and synchronization in power electronics dominated systems. The manuscripts may include, but are not limited to:
- Experiences of oscillatory behaviour observed in power electronics dominated systems,
- Understanding the mechanism of and predicting electrical interactions that originate oscillatory behaviour which can lead to instability,
- Control and prediction of instability involving synchronization in decentralized power grids,
- Modelling and stability analysis methods that can accurately describe the large-scale dynamics of power electronics systems,
- Nonlinear analysis of power converter interactions in decentralized electric power systems,
- Nonlinear robust controller design of grid connected power electronic converters,
- Stability of power systems composed by clustered microgrids and role of the interface converter interconnecting microgrids on the power system stability,
- Stability of AC/DC hybrid power electronics systems.
Keywords: synchronization, voltage source converter, power electronics systems, stability, coupled oscillators, interaction mechanisms
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