A Novel DC Bus Control Signal Using Pulse Frequency Modulation for DC Microgrids

In order to improve the reliability and the stability of DC microgrids (MG) and performance of DC bus voltage regulator, at the same time, a new concept of DC bus control signal (DBCS) algorithm based on pulse frequency variation is proposed. In conventional power management algorithms such as centralized control, power line signaling (PLS), and DC bus signaling (DBS), the reliability of DC MGs could be degraded. In this paper, the switching ripple carried on the dc-bus voltage is presented as the operating information for communication between interfaced converters in DC MG. By varying the switching frequency of a grid-connected DC-DC converter according to the load conditions, all DC MG components connected to the DC bus can be aware of the operating status. Experimental results verify the practical feasibility and the effectiveness of the proposed strategy through the 3.3 kW prototype dual active bridge converter.