Distributed Energy Dynamics Control for Stable Power Electronic-Enabled Electric Power Systems

Abstract

The increasing penetration of renewable and inverter-based resources is transforming modern power systems into fast, nonlinear, and heterogeneous networks. These converterdominated systems operate on timescales much faster than traditional synchronous machines, making conventional modeling and control approaches, rooted in quasi-static phasor analysis and centralized architectures, inadequate for ensuring stability and scalability. This thesis adopts an energy space modeling approach grounded in first principles of energy conservation and system interconnection. It extends the previously introduced second-order energy dynamics model by relaxing the assumption that energy in tangent space can be treated as an independent disturbance. The resulting contribution is a third-order model that treats stored energy in tangent space as a dynamic state, enabling more expressive and accurate modeling of fast-timescale system behavior. Leveraging this extended energy space model, the thesis develops a multilayered distributed control architecture in which the nonlinear physical dynamics of each component are lifted to the higher-level linear energy space, capturing internal energy dynamics and real/reactive power flows, and integrated with the lower-level physical dynamics with well-defined mappings. Distributed controllers are designed in this energy space using only local states and minimal neighbor interaction, assuming a system-level coordination mechanism provides consistent references. Two control strategies, energy-based feedback linearizing control and sliding mode control, are developed and shown to achieve asymptotic convergence to reference outputs. The framework is validated on two systems: an inverter-controlled RLC circuit and a synchronous generator under load. Finally, the energy space framework is extended to structurally model inter-area oscillations (IAOs). An inter-area variable is defined as the difference between power incident on a tie-line from Area I and power reflected into tie-line from Area II. Simulations on a 3-bus, 2-area system confirm consistency with eigenmode analysis and show how tie-line strength and generator inertia affect IAO dynamics. A novel resonance phenomenon is also identified: instability arising from interaction between a system’s natural IAO frequency and time-varying disturbances from intermittent DERs. This previously unmodeled behavior is captured explicitly within the energy dynamics framework and may help explain recent blackout events in the Iberian Peninsula.