Lypunov theory combined with small signal linearization for regulated operation of a hybridDC/ACmicrogrid

Abstract

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.