Novel leakage current study model based on finite element analysis for photovoltaic panels

Nowadays, leakage current seems to be one of the major constraints of photovoltaic inverters. Due to the non-identical switching transitions and dead-time, PWM modulation scheme generate a large DC side high frequency leakage current flowing through the parasitic capacitance of the PV panel to the ground in transfromerless PV systems. Moreover, the high voltage bias between the cell circuit and frame of the PV panel leads to potential induced leakage current flowing through the insulation of the panel to the ground. Both of them have a profound impact, such as slow degradation effect and human safety. This paper proposed a novel finite element analysis based model for the PV panel. Useful information about the distribution of electric field, magnetic field, potential and eddy current can be acquired from the proposed model. The influence of air humidity is also studied in detailed. Compared to the other existing circuit models, the proposed FEM model provides an intensively investigation and discussion for the leakage current in individual PV panel component.