Operation of Virtual Droop Resistance-Based Parallel Connected Boost Converters for Power Sharing and Minimization of Circulating Current

摘要

More and more installation of DC sources like solar photovoltaic sources encourages to bring back the DC loads that uses DC generated power directly to meet the DC loads. In such DC microgrid system, voltage stability poses a major challenge because of low inertia in absence of rotating mass-based generating system. This paper proposes a controller for boost converter associated with DC source that ensures the parallel operation in multi-source-based system. Other than this objective, the controller performs well to restores its voltage under different contigent conditions like occurence of fault, large variation in load demand, etc. In response to voltage oscillations due to such unforseen events, the proposed controller controls the converter's voltage by properly generating PWM pulses to the boost converters. To ensure proper load sharing between the sources and minimization of circulating currents, a virtual droop control method is incorporated by providing virtual Rdroop in series with cable resistance of DC microgrid. Also robustness of the proposed controller is tested under occurence of fault. The results clearly attest the effectiveness of the controller in proposed stand-alone microgrid.