Supercapacitor Integrated Railway Static Power Conditioner for Regenerative Braking Energy Recycling and Power Quality Improvement of High-Speed Railway System

In order to increase the utilization rate of the regenerative braking energy (RBE), reduce the operation cost, and improve the power quality of traction power supply system (TPSS) in high-speed railway, a supercapacitor (SC)-based energy storage system (SCESS) integrated railway static power conditioner (RPC) is presented in this article. In this scheme, the SC is connected onto the dc link of the RPC via a bidirectional dc-dc converter. A hierarchical control strategy, with an energy management layer and a converter control layer, is presented. Four operation modes and transition conditions of SCESS-RPC are elaborated in detail in the energy management layer. To obtain rapid and stable control performance, in the converter control layer, a passivity-based control (PBC)-based nonlinear controller is designed for the RPC, and an optimal control strategy based on the linear quadratic regulator with integral action (LQRI) is adopted for the bidirectional dc-dc converter. By means of simulations and experiments, the feasibility of the proposed topology and control strategy are verified.