Recursive fast terminal sliding mode control in voltage source inverter for a low-voltage microgrid system

摘要

This study proposes a recursive fast terminal sliding mode control (FTSMC) for a low-voltage microgrid system operating in grid connected and islanding mode of operation. The microgrid is presumed to be a higher order distribution system. A recursive approach of FTSMC is used in the voltage source inverter to control the bus voltage nearer to the main grid and farther away from the micro source in a grid connected system. Using this methodology good tracking of the bus voltage in case of grid connection and output voltage in case of islanding mode with a faster convergence is observed. The controlled voltage has low total harmonic distortion and small steady-state error. The algorithm requires only single voltage sensing requirement for control operation. This study also reveals the inability of the classical sliding mode control for regulating the bus voltage which is at a far end of the microgrid system. The PSCAD/EMTDC software (version 4.2) has been used for simulation studies. The experimental results are shown for a scaled down model using LabVIEW programmed field-programmable gate array controller in islanded mode of operation to verify the performance of the proposed FTSMC.