Combined maximum power point with constant power generation control for grid-connected photovoltaic inverters considering long-term mission profiles

A hybrid MPPT-CPG control concept is proposed for grid-connected PV inverters considering long-term mission profiles and system-level power management requirements.[۱] The proposed control strategy allows increasing the utilization factor of PVinverters and reducing temperature changes in power devices. In addition, by smoothing and limiting the output power of the PV inverter to some extent, it is useful for power management at the system level. This advantage is especially important for scaling up PV installations with existing grid infrastructure under high PV penetration in the future [۲]. The mentioned benefits are compromised by the power dissipation due to the proposed control, allowing the optimal choice of the power control limit depending on the specific mission profiles. In the case of the study of a single-phase PV inverter, the power limit is chosen as ۸۰% of the maximum feed power of the PV panels, which corresponds to an energy efficiency reduction of ۶.۲۳% under a specific annual mission profile. The use of PV inverter is increased by ۱۷% and the lifetime of electrical devices is increased to ۵.۶۲ times that in MPPT control mode. A case study of a single-phase PV inverter under annual operation is presented, analyzing thermal load, lifetime, and annual energy efficiency. This revealed the trade-off factors for power limit selection and also confirmed the feasibility and effectiveness of the proposed control concept.

کلیدواژه ها:

maximum power point tracking (MPPT) ، photovoltaic (PV) inverters ، reliability ، energy saving.