ISMC-based system-level coordinated control of Active Front-End converter and DSTATCOM for transient stability enhancement in shipboard hybrid AC/DC microgrids

Abstract Shipboard hybrid AC/DC microgrids (MGs) are increasingly deployed to integrate advanced propulsion systems and pulsed power loads while maintaining high power quality and reliability. However, rapid load fluctuations can induce severe transient disturbances that threaten system stability. This paper proposes a system-level coordinated control strategy for an Active Front-End (AFE) converter and a Distribution Static Compensator (DSTATCOM) to enhance transient stability and power quality in shipboard hybrid AC/DC MGs. The pulsed loads on the DC side are supplied through the AFE converter, which regulates the DC bus voltage and manages real and reactive power exchange between the DC and AC sides. To ensure precise dynamic response, an Integral Sliding Mode Control (ISMC) scheme is designed for the AFE to accurately track DC voltage and the dq-axis​ current components under severe disturbances. Similarly, the DSTATCOM is employed to correct the power factor at the Point of Common Coupling (PCC) and stabilize AC bus voltage, with an ISMC-based controller designed to achieve accurate tracking of its DC-link voltage and dq-axis current components. The performance of the proposed ISMC-based system-level coordinated AFE and DSTATCOM control is compared with conventional PI, Non-singular Terminal SMC (NT-SMC), and Active Disturbance Rejection Control (ADRC) approaches under various dynamic scenarios, including pulsed load steps, propulsion load variations, and combined disturbances. Simulation results demonstrate that the proposed ISMC method reduces DC-link voltage deviation by 45% compared to conventional PI control and improves transient settling time by nearly 30% under severe pulsed load conditions. Furthermore, the THD of voltage and current at the AC bus are limited to 3.36%, 4.38%, respectively, while maintaining a near-unity power factor. The findings confirm that ISMC-based system-level coordinated control of AFE and DSTATCOM provides an improved solution for enhancing transient stability and power quality in shipboard hybrid AC/DC MGs under model and parameter uncertainties.