METHOD FOR COMPENSATING FOR PARTIAL SHADE IN PHOTOVOLTAIC POWER SYSTEM

摘要

There is provided a method for compensating for partial shade using a photovoltaic power system, in which a plurality of serial-connected arrays of solar cell modules are connected in parallel, the arrays are connected to a converter, and a final power is outputted from the converter. The method includes the steps of: connecting an auxiliary power source to each solar cell module; if a low solar radiation is detected by an MPPT controller, supplying a necessary power through the auxiliary power source at a time, thereby maintaining constant voltage and preventing a temporarily shutdown; connecting in parallel the solar cell modules of the serial- connected arrays in multi-stages; and varying an operating voltage ratio of the solar cell module by controlling an off duty cycle of each chopper at the MPPT controller, thereby generating maximum output from the serial-connected array of each solar cell module.