A Simplified Strategy for Smooth Grid Switching in Coal Mine Microgrids Using Enhanced Voltage Loop and LADRC Pre-Sync Control

To address the transient overvoltage and oscillation issues caused by the rapid conversion between the underground DC and surface AC power supply modes during the on-grid/off-grid switching process of coal mine microgrids, this paper proposes a smooth switching strategy based on an improved voltage loop and a linear active disturbance rejection controller (LADRC) pre-synchronization control. This strategy combines current compensation technology with disturbance estimation based on an extended state observer (LESO), achieving real-time compensation and dynamic adjustment of disturbances during the switching process. It significantly reduces the risk of transient overvoltage and oscillation, and enhances the dynamic response performance and robustness of the system.