Photovoltaic inverter system and method of starting same at high open-circuit voltage

摘要

A power inverter system (200) includes a DC to AC inverter (230) configured to convert DC voltage from a DC power source (210) to AC voltage. A DC link (226) couples the DC power source (210) and the inverter (230). An inverter pre-charger (350) operates to pre-charge the inverter (230) to achieve a desired DC link voltage prior to connecting the power inverter system (200) to an AC power grid (240). A phased lock loop (352) synchronizes the pre-charged inverter (230) to the AC power grid (240) prior to connecting the power inverter system (200) to the AC power grid (240). The pre-charged inverter (230) regulates the DC link voltage to about the minimum voltage level that allows control of AC grid currents via the inverter (230) subsequent to connecting the power inverter system (200) to the AC grid (240). The inverter (230) operates in a maximum power point tracking control mode only subsequent to a first voltage transient caused by connecting the DC power source (210) to energize the power inverter system (200).