| Abstract |
This work introduces a single-stage, bidirectional, isolated AC-DC converter with capability to supply ancillary services to grid. The converter is based on a simplification of the two-stage configuration where the power is transferred to grid by means of the low frequency voltage components of a voltage source inverter (VSI) meanwhile high frequency components are filtrated. In the proposed converter, high frequency components of the voltage are exploited for isolated power transfer to the DC by means of high Q resonant tanks and an additional phase-shift modulated active bridge. The proposed converter operates under similar principles to the two-stage configuration but with lower component count. This way, DC link capacitor is still present and designed to provide virtual inertia to the grid. The virtual inertia is achieved by an additional outer control loop that links frequency variations to the DC voltage control reference. Thus, the proposed converter is able to perform isolated and bidirectional AC-DC conversion and to provide the ancillary service of virtual inertia to the grid. The reliability of the system is demonstrated by means of simulation analysis of a 2.4 kW system. |
