A Continuous Power-Supply Control Strategy for Critical Loads Based on Dynamic Feedforward Compensation of the Source-Side Power Deficit

To prevent DC-bus voltage sag and overvoltage during power-supply takeover after a public-grid outage in an industrial microgrid, this study proposes a continuous power-supply control strategy for critical loads that combines dynamic source-side-deficit feedforward with DC-bus energy compensation. Direct feedforward of real-time load power can overlap with residual injection from the grid-side converter, repeatedly charging the DC-bus capacitor and causing an overvoltage. Based on the three-port power-balance relationship among the grid-side interface, bidirectional DC–DC converter, and load-side grid-forming interface, the handover transient is attributed to residual source-side supply, delayed DC–DC power buildup, and persistent load-side consumption. The source-side power deficit, defined as the difference between the load-side DC-power demand and actual source-side injected power, is filtered to generate a dynamic feedforward signal. Thus, storage power is established adaptively as source-side supply withdraws, avoiding repeated compensation. An energy-compensation branch derived from the relation between DC-bus capacitor energy and squared bus voltage corrects residual mismatch caused by filtering, converter losses, and DC–DC dynamic lag. Mathematical models and a small-signal three-port DC-bus model are developed. Simulation and hardware-in-the-loop results verify the effectiveness of the proposed strategy.