Photovoltaic Inverter Efficiency and Lifetime Trade-off using Model based Real-Time Optimization

Lifetime of the photovoltaic (PV) inverters is influenced by its power profile. The reliability of such PV inverters is affected by the thermal fatigue cycles witnessed by the underlying components. However, there is a trade-off between the inverter efficiency and the fatigue witnessed by its components. With a systematic formulation of this trade-off, a real-time nonlinear optimization problem is formulated to generate the appropriate reactive power set-points to the PV inverter controller. The proposed approach improves the lifetime of the inverters while keeping its efficiency above desired threshold value. The time domain loss and damage models that uses PV power profile as an input are critical to the proposed optimization framework. The proposed framework provides an option to the customer to operate the PV inverter with an objective of lifetime improvement under the acceptable losses by flattening the component thermal fatigue cycles. The framework is evaluated using the PV power profile of a 10 kVA PV inverter with various simulated case studies.