A Multi-Boost Converter for DC Capacitor Ripple Voltage Reduction to Enhance Irradiance Dependent PV-to-Grid Power Quality

The power electronics enriched grid tied Photo-voltaic power plants are increasingly tested for grid resiliency, power quality, and reliability. The energy balance implementation needs large DC bus capacitors, which ripple affects grid power quality as well as its own lifetime and system reliability. This work has proposed a multi-boost converter which is designed to track the maximum ripple, and hence provide its reduction in steps "online" for different levels of irradiance. The ripple voltage is translating to significant harmonics at grid end which is worsened by low values of irradiance. The simulation results show 50.4 % grid current reduction by 3.37 % ripple voltage reduction for low irradiance, and 16.4 % THD reduction by performing 1.53 % ripple voltage reduction for higher irradiance. This has effectively reduced voltage stress on DC bus capacitor offering better lifetime, hence increasing the reliability of the PV-inverter system.