PV-Grid Assisted Uninterruptible Power Supply System for a BLDC Motor Drive

A photovoltaic (PV) grid-interactive system is described in this work for applications that require an uninterrupted power supply. The presented system is such that it allows BLDC motor to run at rated speed at all times irrespective of change in irradiation. A PV-grid hybrid system is a reliable source of supply, whenever the PV system is unable to supply sufficient power to run the motor at rated speed, the grid supplies the deficit power. Additionally, when the motor is not in use, the surplus PV system generated power can be fed to grid. The input voltage of the voltage source inverter (VSI) is regulated by a PI-based outer voltage control and current control is achieved using a proportional resonant (PR) controller. The grid-interfaced PV fed BLDC motor is designed and simulated under various conditions like BLDC motor fed by both PV and grid, BLDC motor not in operation and transition from PV to grid supply. Results from various operating modes demonstrate that the BLDC motor drive fed from a hybrid system operates steadily and dependably enhancing the system performance with reduction in per unit energy cost.