A Novel Cooperative Control Strategy to Mitigate PV Power Fluctuation and Increase its Penetration

Abstract

This paper proposes a novel optimization-based power sharing control strategy to moderate PV power intermittency and increase its penetration. Such a control strategy aims to minimize the total PV power sensitivity to the light change by re-distributing the demand power among available PV units such that the demanding power is met with minimal variation. PV plant is coupled with the grid utility, and it should maintain a specific amount of power determined by the grid operator. However, due to the PV power sensitivity to the light, the delivered power at the coupling point fluctuates and leads to undesirable responses such as grid frequency excursion, stability problems, and unoptimized power generation. To address such issues, we formulate an optimization problem to reduce the total PV power sensitivity by selecting the optimal reference voltage for each PV panel. We define the power sensitivity as the rate of power change to light fluctuation to be the objective function of the proposed optimization problem, and the selected reference voltages for all PV panels are the decision variables. Compared to other conventional power-sharing techniques such as the same utilization level, droop control, and lookup table, MATLAB simulation results verify the contribution of the proposed algorithm’s performance superiority in PV power sensitivity reduction, grid stability assurance, and power generation enhancement. Moreover, when there is insufficient PV power to meet the grid operator’s demand, the proposed algorithm automatically sets the entire PV plant to work at its MPP without switching circuits.

Keywords

• PV power
• PV penetration
• power fluctuation
• power sharing
• optimization
• control strategy