Summary This paper concentrates on the issues with the aim of providing a constant dc‐link voltage and desired power sharing for a distributed energy storage system (DESS)‐based hybrid microgrid under load variations. The hybrid microgrid which is consisted of PV system, lithium battery‐based storage system and a grid‐connected dc/ac converter are controlled by designing a controller based on the zero dynamics‐based mathematical equations of all used converters. Two buck and bidirectional buck‐boost dc/dc converters employed in PV and DESS systems, respectively, are responsible for damping the dc‐link voltage fluctuations, and also the grid‐connected converter is set to enhance the grid power quality and supply continuously the grid‐connected loads. The main contributions of the proposed control technique are simplicity and providing the simultaneous stable performance for both DC and AC sides under both DC and grid‐connected loads variations. Moreover, another contribution of the proposed control technique is providing accurate coordination in both steady‐state and dynamic conditions. To analyze the proposed controller, the dynamic operations of the converters in various operating conditions are evaluated. In this evaluation, several curves based on their zero dynamics are achieved, and their desired operations are completely investigated in different operating conditions. Simulation results in MATLAB/SIMULINK verify the proposed controller ability at reaching the desired zero dynamics and the stable performance of the proposed hybrid microgrid.

Summary This paper proposes a new control strategy for enforcing a AC‐DC hybrid microgrid to attain stable responses in both steady state and dynamic operating conditions. The proposed controller is designed based on combining direct Lyapunov method and small signal linearization (SSL). The dynamic parts of converter control functions are achieved through providing the global asymptotical stability of the hybrid microgrid by using its total saved energy function. Then, the steady‐state components of the controller, unlike other existing Lyapunov‐based methods, are obtained according to SSL‐based mathematical terms as the main novelty of this paper. This novelty simultaneously provides several contributions within the proposed control technique structure as (a) the direct control of the PCC voltage frequency and DC‐link voltage errors, (b) the enhanced decoupling feature for DC/AC converter current, and (c) the direct control of the input voltage error for bidirectional DC/DC converter. Finally, comparative simulation results in MATLAB/Simulink software are presented to verify the superiority of proposed controller combined with SSL under AC and DC load variations, discharging/charging of storage unit, different grid power factors and AC loads shared among grid side and DC sources.

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