Stability Control of Photovoltaic Power Generation System Through Virtual Resistance Fitting Under Variable Irradiation Conditions

The oscillation suppression strategy for PV grid-connected systems (PVGS) designed under specific operating conditions may not adapt well to variable irradiation conditions. A virtual resistance fitting-based stability control strategy is proposed in this paper. The proposed strategy first fitted the desired virtual resistance function of the PV converter under variable irradiation conditions, and then introduced the virtual resistance by using a band-pass filter and current feedback to counteract the negative resistance effect. The proposed strategy is simple in design and effectively enhances the stability of the system under variable illumination conditions without affecting the steady-state output.