Enhanced control of energy storage converter for stabilizing renewable energy integrated systems

• Relationship between oscillatory stability and power coupling has been revealed based on the power-domain admittance model. • An enhanced control for energy storage converters is proposed to enhance the stability of renewable energy integrated system. • The optimal placement of the energy storage system is proposed based on stability evaluation and weak points’ identification. The increasing penetration of renewable energy sources has raised the risk of wideband oscillations in renewable energy integrated systems. However, applying existing oscillation suppression methods to individual units in renewable power plants presents significant challenges. With the rapid advancement of energy storage technology, if the control strategy is properly designed, energy storage converters can effectively address oscillatory stability issues. To this end, an enhanced control integrating self-stabilization and power decoupling capabilities for power control-based energy storage converters is proposed to improve the oscillation stability of renewable energy integrated systems. First, a power-domain admittance model is established to analyze the power coupling characteristics of power control-based energy storage converter. The relationship between power coupling and oscillatory stability is then elucidated. Subsequently, the insufficient self-power decoupling ability of power control-based energy storage converters under weak grid conditions is examined. It is determined that reducing power coupling is crucial for addressing oscillatory stability issues. On this basis, the structure, parameters design, and power decoupling capability of the enhanced control strategy are analyzed and verified. Finally, the effectiveness of the proposed strategy is validated through a case study of a practical renewable energy integrated system under various operating conditions using PSCAD/EMTDC simulations.