Bidirectional Power Flow Controllability of Inverter-Dominated Radial Microgrids Incorporating Harmonic Mitigation Capabilities

As a consequence of having a singular point of interconnection with the upstream grid, a grid-connected radial microgrid (MG) can support ancillary functionalities by steering its multiple power electronic inverters to achieve controllability over the power flow. Nonetheless, pure active and reactive power dispatchability at the MG's point of interconnection is difficult to be achieved due to distortion currents drawn by existing nonlinear loads. This paper presents a control strategy applied to grid-connected radial MGs, allowing to coordinate their inverters to regulate the dispatch of the active and reactive powers while concomitantly offering distributed compensation of harmonic currents. Thus, the MG operates as a single-controllable entity, and its power dispatch can support demand response without propagating harmonics to the upstream grid. The effectiveness of the power flow regulation and harmonic mitigation are demonstrated by experimental results in a single-phase MG prototype considering two inverters and multiple loads.