Summary In a hybrid AC‐DC microgrid, the interlinking converter (IC) is used for tying AC and DC subgrids as the medium of power transfer between the two subgrids. Within an islanded hybrid microgrid (HMG) power transfer between droop controlled AC and DC subgrids is done through IC to achieve power sharing between the subgrids. Further, in this paper, a modified control strategy for IC is proposed for carrying out active power filtering also. Under non‐linear loading conditions, IC in conjunction with the DC subgrid can be used as an active power filter (APF), to filter the AC side line currents and to maintain a sinusoidal voltage at the AC bus. This type of control of the IC in an islanded HMG is so far not much investigated. In this paper, an HMG is simulated in MATLAB/Simulink for different loading conditions, considering linear and non‐linear loads and various set of simulation studies are presented for validating the effectiveness of the proposed control strategy. The system is also implemented using real‐time digital simulator hardware, and the obtained results are presented to support the efficacy of the proposed control strategy.

Summary An interlinking converter (IC) in a hybrid AC‐DC microgrid (HMG) is the power transfer medium between the AC and DC subgrids. This article proposes a modified control strategy of IC for carrying out the power transfer between the subgrids without sensing the AC voltages. This control strategy directly extracts the AC voltages from the gate signals used for controlling the IC. The omission of AC voltage sensing process upgrades the reliability of the system and also minimizes the size and cost of the system considerably. The paper also studies the operation of IC as an active power filter (APF) under non‐linear loading conditions, with the objective of reducing the interlinking power flow. APF using IC while carrying out power transfer between the subgrids generate high power losses. This issue is addressed by controlling the IC using the power request method, thereby ensuring a reduced power flow through the IC. In this article, the results obtained from the simulation of the HMG in MATLAB/Simulink are presented to verify effectiveness of the proposed control strategy. The results of real‐time simulations performed using OPAL‐RT (OP4500) real‐time simulator test bed are also presented to validate the potency of the proposed control strategy.

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Hybrid AC–DC microgrid (HMG) is formed by connecting separate AC and DC microgrids with an interlinking converter (IC). In islanded mode of operation of the HMG its AC and DC subgrids are droop controlled to achieve power-sharing. The power flow between the subgrids happens through the IC, which regulates the amount of power being transferred based on the values of the frequency of AC bus voltage and the voltage at the DC bus. This paper presents the utilization of power-electronic converters to form the droop-controlled AC–DC subgrids of an islanded HMG which will be beneficial for further studies of IC and HMG. The detailed design and analysis of the closed-loop control system parameters of both the power converters is presented. The results obtained from simulations carried out in MATLAB/Simulink, and the real-time simulation results obtained by implementation using OPAL-RT OP4500 real-time digital simulator hardware are presented for the verification.

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