Efficiency Analysis of VSC Controllers: Discrete PWM vs Improved Hysteresis PWM for Voltage Sag Improvement in Grid-Connected Hybrid PV-Wind Systems

This study compares discrete pulse width modulation (PWM) and improved hysteresis PWM controllers for voltage sag mitigation in grid-connected hybrid PV-wind power systems with dynamic voltage restorers (DVRs) based on battery storage and superconducting magnetic energy storage (SMES). The analysis focuses on the controllers' effectiveness in maintaining voltage stability and reducing total harmonic distortion (THD) under various grid conditions. Simulation results show that while both controllers effectively mitigate voltage sags, the improved hysteresis PWM demonstrates superior performance in terms of THD reduction and dynamic response. The findings provide insights into selecting optimal VSC controllers for enhancing the reliability and efficiency of grid-connected renewable energy systems.