A rooftop photovoltaic (PV) system is a significant solution of building-integrated centralized generation in the low-voltage (LV) DC grid. The drilling-free rooftop PV-inductive wireless power transfer (PV-IWPT) system for the LVDC grid can reduce the installation and post-maintenance costs, with the elimination of physical cable connections and preventing breaking of thermal bridge and rain penetration between the rooftop and the inside of the building. Moreover, it has inherent isolation properties between the input and the output terminals. However, it is challenging for the PV-IWPT system to simultaneously achieve the maximum power point tracking (MPPT) for the PV panels and the maximum efficiency point tracking (MEPT) for the system even under diverse irradiance conditions. In this paper, we propose an efficient PV-IWPT system, which consists of a series-series IWPT converter, driven by the PV panels and loaded by the LVDC grid directly. Moreover, we apply in the proposed system a particle swarm optimization with an auxiliary Perturb and Observe (P&O) algorithm and a load matching method without wireless feedback communication to realize MPPT and MEPT in the overall PV-IWPT system simultaneously. Finally, we analyze theoretically and verify experimentally the proposed PV-IWPT system in a 500-W experimental platform under different irradiance conditions.