COMPONENT VOLTAGE LIMITING CIRCUIT AND DEVICE APPLYING SAME

A circuit for component voltage limitation and an apparatus for applying the same. A detection-and-control unit detects a parameter of a photovoltaic-cell string, and controls operation of a switch unit according to the parameter of the photovoltaic-cell string. The switch unit controls, according to control of the detection-and-control unit, at least one photovoltaic cell connected to the switch unit to operate in the voltage-limited mode, or a photovoltaic cell operating in a voltage-limited mode to resume a normal output. In a case that the switch unit controls the at least one photovoltaic cell connected to the switch unit to operate in the voltage-limited mode according to control of the detection-and-control unit, a voltage of the photovoltaic-cell string can be reduced. Thereby, a quantity of photovoltaic modules connected in series can be increased while the highest voltage of the system is guaranteed not to exceed a corresponding requirement, and a cost of the system is reduced. In a case that that the switch unit controls the photovoltaic cell operating in the voltage-limited mode to resume the normal output according to control of the detection-and-control unit, an output voltage of the photovoltaic-cell string can be increased. Thereby, the rate of utilization on the direct voltage and the PVIR of DC/AC are improved for the photovoltaic system.