Control of Interlinking Converter for Power Quality Improvement in Hybrid Microgrid

This article deals with control of a hybrid ac/dc microgrid (MG) comprising photovoltaic array (PV), battery energy storage (ES), small hydroelectric (SH) generator, and wind energy conversion system (WECS). WECS is connected via static power electronic switch (SPES). The notion of ac/dc MG has emerged due to progress in both ac- and dc-based renewable energy sources (RESs) and loads. Ac and dc buses are adjoined using an interlinking converter (ILC) for bidirectional exchange of power. Depending upon generation and demand, four operating modes of hybrid ac/dc MG are formed, which allow independent operation at both ac and dc bus. Modes are formed to maximize utilization of RESs at their respective buses. Maximum power point algorithms are used to extract maximum power from WECS and solar PV array. Moreover, a filtered-x affine projection Versoria (FxAPV) adaptive filter is employed to extract active and reactive parts of load currents so that stator currents of doubly fed induction generator (DFIG) and hydrogenerator are harmonics free. System voltage and frequency of ac bus are controlled using ILC, whereas bidirectional dc-dc converter (BDDC) regulates voltage on dc side. Performance of system is verified on a hardware prototype.