Constant Power Load Instability Mitigation in DC Shipboard Power Systems Using Negative Series Virtual Inductor Method

DC distribution technology has become the new choice and the trending technology of shipboard power systems for its advancement over its AC counterpart. In DC shipboard power systems, the bus voltage stability is a critical issue. The presence of tightly controlled high-power constant power load can induce system-level voltage instability. To mitigate such a problem, a novel compensation method based on model-derived specially designed negative virtual inductance loop is proposed in this paper. The mechanism of the proposed method is presented in detail. In addition to that, the proposed compensation method is compliable with both voltage-controlled and droop-controlled converters. Simulations are carried out to validate the proposed method, and the results show enhanced stability margin and capability when feeding constant power loads.