Droop controller design methods for isolated DC-DC converter in DC grid battery energy storage applications

Droop control is a potential solution to assign the power share for multiple DC power sources such as battery energy storage systems in a DC micro-grid, without demanding communication requirement. The design objective of the droop controller is to regulate the DC-DC converter virtual output impedance. As the major contribution of this paper, two types of DC droop controllers are proposed for the isolated DC-DC converter in battery energy storage applications in DC grid. One method provides cost effective solution by only designing the output voltage compensator without current sensor. The other method requires a current-feedback loop but provides accurate and linear output droop. An isolated DC-DC converter prototype was built and the test results were reported for both droop controller designs.