Repetitive Controller for Low Grid Current Harmonics in a Hybrid Parallel Electrolysis Rectifier

As water electrolysis for energy storage or sector coupling becomes more relevant, suitable rectifiers for grid integration are needed. A promising rectifier concept for this application is a combination of a thyristor rectifier, which offers a high efficiency at the needed high currents, and a parallel voltage source inverter (VSI) for grid current correction and DC-output smoothing at the same time [1]. However, as the desired low grid current harmonics can only hardly be achieved with a conventional controller, a repetitive control concept for the VSI is introduced. The proposed system is verified with measurements on a 5 kW demonstrator circuit of the proposed topology.