Photovoltaic system
Disclosed is a photovoltaic system including a power optimizer, capable of minimizing noise occurring due to shading, an error in an output power of a photovoltaic module, etc. while a maximum power point tracking (MPPT) algorithm is performed. The photovoltaic system includes a photovoltaic module; a power optimizer; and an inverter, wherein the power optimizer includes: an input unit configured to receive an output power of the photovoltaic module; a sensing unit configured to sense an output voltage and an output current of the photovoltaic module; and a controller configured to control an output of the power optimizer, by comparing the presently-sensed current with a previously-sensed current.
1. A photovoltaic system, comprising:
a plurality of photovoltaic modules serially connected and being configured to generate power from solar light;
a power optimizer coupled to the plurality of photovoltaic module to receive the generated power as an input power and to provide an output power, the power optimizer comprising:
an input unit coupled to the plurality of photovoltaic modules to receive the generated power;
a sensing unit configured to sense voltage and current of the power generated by the plurality of photovoltaic modules;
a DC-DC converter configured to lower or boost a voltage of the input power of the power optimizer by a preset reference value, with respect to a voltage of the output power of the power optimizer;
a bypass unit;
a controller configured to:
execute a maximum power point tracking (MPPT) algorithm;
stop executing the MPPT algorithm and operate the bypass unit to bypass the output power of the power optimizer when a difference between presently-sensed current sensed by the sensing unit and previously-sensed current sensed by the sensing unit exceeds a preset reference value;
search for a maximum power point based on the voltage and the current sensed by the sensing unit by executing the MPPT algorithm when a difference between the presently-sensed current and the previously-sensed current does not exceed a preset reference value;
determine the output voltage of the output power of the power optimizer based on a maximum power corresponding to the searched maximum power point;
an inverter coupled to the DC-DC converter to convert DC voltage received from the DC-DC converter to AC voltage to provide to a load; and
a power supply unit configured to supply power to the sensing unit, the controller, the DC-DC converter, and the bypass unit, based on the generated power received by the input unit.
2. The photovoltaic system of claim 1 , wherein the controller is further configured to:
determine the output voltage of the output power of the power optimizer based on the generated power received by the input unit when the difference between the presently-sensed current and the previously-sensed current does exceed the preset reference value.
3. The photovoltaic system of claim 1 , wherein the bypass unit includes one or more bypass diodes.