Among the exiting multifunctional photovoltaic (PV) inverters (MPVIs), the main challenges are low efficiency, undesired harmonic emission, and weak compensation capability. In this paper, a theoretical study via rotating phasor to the PV curves is firstly proposed to figure out the undesired harmonic emission puzzle in different PV inverters as well as to provide the foundation for PV inverters to achieve multifunction ability under varying load conditions. On the other hand, a single-phase time-sharing miniboost MPVI with different operation modes is proposed and operated under varying PV and load conditions in order to improve its efficiency and compensation capability without undesired harmonic emission. Corresponding control strategy and stability analysis are given. Finally, a 1.5-kW prototype is presented, benchmarked against harmonic emission issues, compensation capability, and efficiency. Experimental results clearly indicate that the proposed topology and control method can perform the active power injection and power quality compensation with better efficiency and avoiding harmonic emission into the grid dynamically.