Photovoltaic-energy storage hybrid electric spring based on three-port converters

The large-scale integration of renewable energy sources (RES) into the power grid has led to an imbalance between supply and demand, thereby increasing the demand for energy storage. As an emerging demand-side management technology, the Electric Spring (ES) can effectively mitigate the demand for energy storage by transferring power fluctuations to non-critical loads (NCLs). However, almost all existing ESs adopt a single-input voltage-source-inverter (VSI) as the main circuit, which undoubtedly limits their ability to integrate multiple inputs and their power compensation performance. To address this issue, an improved ES based on a three-port DC-AC converter, named as TPC-ES, is proposed in this work. The proposed topology enables flexible coordination between photovoltaic (PV) generation and battery storage, while the asymmetric dual-carrier modulation scheme provides effective power decoupling and flexible power regulation among the three ports. The topology, operating principles, and control strategies of the TPC-ES are presented in detail, and its effectiveness has been verified by simulation and experiment results.