Kosuke Kurokawa

Solar cells have a current-voltage (I-V) characteristic affected by the radiation and temperature. To obtain the maximum electricity from solar cells, the power converters for PV (photovoltaic) modules have a function called MPPT (maximum power point tracking). Under the various conditions, the dc input voltage or current is controlled to track the maximum power point (MPP) where the PV modules feed the maximum output power. A module integrated converter (MIC) is individually installed behind of a PV module. In this type, manufacturers can obtain the basic characteristics of the PV module in the manufacturing process. Therefore, the domain of MPP can be predicted. The plane division (PD) MPPT method takes full advantage of the known I-V characteristic. The I-V plane is divided into two domains by a PD function. One includes MPPs and the other one doesn't. Using the PD function, the operating point can rapidly approach the MPP. In this paper, a combination of two or three linear functions is proposed and tested. In circuit experiments, the measured approaching time to the MPPs is reduced from 87.0% to 65.0% for the combination of three linear functions compared to the IncCond algorithm. Based on the measured data, the proposed functions are also compared to the previous PD functions. Consequently, the square root function and the combination of three linear functions are superior to the others. The PD-MPPT, which can be easily added to various MPPT algorithms, is effective to accelerate the MPPT operation of the MIC