Enhancing DC-Bus Voltage Stability in DC Distribution Networks with Constant Power Loads Using Modified Integral Sliding Mode Controllers

In DC distribution networks (DCDNs), the integration of constant power loads (CPLs) with the DC bus can result in voltage fluctuations or system instability due to their negative damping characteristics. This paper introduces an innovative solution by implementing an integral sliding mode controller coupled with a modified reaching law. Initially, the dynamical model of DC-DC converters (DDBCs) operating with CPLs is developed. The proposed controller is then carefully designed to ensure system stability, leveraging the Lyapunov stability theory. To validate the controller's effectiveness, extensive simulations are conducted using MATLAB/Simulink, focusing on supply voltage and voltage fluctuations of the DC bus. The controller's performance is rigorously evaluated and compared with an existing controller, highlighting its superior capabilities. Simulation results demonstrate the enhanced performance of the proposed controller through various quantitative metrics, confirming its effectiveness in managing voltage fluctuations and maintaining system stability in DCDNs.