Photovoltaic inverter with control for performing low voltage ride through

摘要

A photovoltaic inverter for coupling a direct current photovoltaic source to an alternating current energy grid and performing a low voltage ride through. The inverter includes a power bridge to convert direct current voltage to alternating current voltage. A switching crowbar is coupled to the photovoltaic energy source and the power bridge. The crowbar has a switching device having a closed position causing the switching crowbar to dissipate energy from the photovoltaic energy source and an open position to allow direct output from the photovoltaic source to the power bridge. A voltage sensor detects a low voltage condition on the grid. A controller is coupled to the voltage sensor and controls the switching crowbar when a low voltage condition is detected. The switching device is placed in the closed position when the voltage from the photovoltaic energy source is higher than a predetermined threshold voltage and the switching device being placed in the open position when the voltage of the photovoltaic source reaches the voltage when the low voltage condition is detected.