POWER SUPPLY SYSTEM AND POWER SUPPLY METHOD

摘要

A low voltage ride-through control system and method for multiple grid-connected power converter, comprising a photovoltaic array (11) and an inverter (12). The inverter comprises a DC/DC conversion unit (13) and a DC/AC inversion unit (14) connected to an output end of the DC/DC conversion unit. An input end of the DC/DC conversion unit is connected to an output end of the photovoltaic array. The inverter is connected to grids at a grid-connecting point. The inverter further comprises a low voltage ride-through detection unit (15) and a low voltage ride-through control unit (16). The low voltage ride-through detection unit is used for detecting the amplitude of a grid voltage at the grid-connecting point, so as to determine whether to trigger low voltage ride-through. In the case of determining to trigger low voltage ride-through, the low voltage ride-through control unit is used for reducing an input voltage of the DC/DC conversion unit, so as to reduce the output voltage of the photovoltaic array, so that the output voltage of the photovoltaic array is less than the voltage tracked at a maximum power point during the steady-state operation of the inverter. The system and method can effectively reduce the capacitance value of a bus and increase the stability of low voltage ride-through.