Harmonic Mitigation as Ancillary Service Provided by Multiple Photovoltaic Inverters

The rapid growth of power electronics-based devices over the past years has increased the harmonics distortion along the power grid. This phenomenon may pose challenges to distribution network operators for managing harmonic levels. This paper proposes an approach to use grid-connected photovoltaic inverters as active filters. The proposed control algorithm consists of a proportional resonance controller for the inner current loop, notch filter for harmonic extraction and an automatic gain functionality to assist the state of the inverter. Active filter operation is activated based on irradiance conditions and system harmonic levels. The main contributions of this work consist in: applying this control scheme to multiple inverters connected at different locations, and using real irradiance and load data to assess the benefits of the proposed application.