An improved synchronverter model and its dynamic behaviour comparison with synchronous generator

As widely-used energy transform device, inverter plays important role in microgrids and distribution generation (DG). Generally, according to its control object, inverter´s controllers can be classified into at least three kinds: constant PQ, droop control and synchronverter (SV) or virtual synchronous generator (VSG). In this paper, an improved synchronverter model is presented. By means of powerful computation ability of digital signal processor (DSP), all basic parts of SG, are reconstructed though program code running in DSP and thus become virtual parts of SV. In this way, SV has absolutely similar structure with actual SG. This similarity ensures they always have really same dynamic behaviour. When stability of multi-SVs-dominated microgrids investigated, inverter model can be replaced by SG model without any accuracy losses. At the same time, this replacement provides a possibility to transfer high matured stability theories which are already applied for large power grid into stability analysis of microgrids or DG. Detailed design methods for SV controller are presented. Via Simulink, dynamic responses of SV and SG are compared under different operation situations. Results prove that SV has same response with similar parameter SG not only in steady state but also in whole process.