nergy storage systems are extensively utilized in distributed generation

microgrids

and new power systems. By regulating the energy storage inverters

it is feasible for the energy storage units to support grid voltage/frequency and mitigate fluctuations in power between sources and loads. However

due to the growing integration of nonlinear loads

such as power electronic converters feeding loads and servo-motor systems

the system damping would be significantly reduced

making the system prone to oscillations under disturbances. Furthermore

numerous influencing factors

such as time-varying parameter uncertainties

modeling errors

and external random disturbances

would degrade the system's performance. As a result

traditional linear control methods can no longer ensure satisfactory performance or prevent frequent instability phenomena. This paper proposes a passive-based control method with nonlinear disturbance observation and the design guidelines for control parameters for voltage source energy storage inverters. The method ensures global stability with passive control

uses a high-gain observer to remove disturbances in real time

and uses Matlab to optimize nonlinear control parameters by assessing system performance. An energy storage inverter rated at 15kVA was designed for experimental validation of the effectiveness of the control strategy's implementation and the correctness of the theoretical analysis.