Wideband dissipativity enhancement of grid-following inverters using virtual element design

Dissipativity provides a convenient approach to predict system stability, which explains the induced resonances from the perspective of damping. To mitigate potential resonances and improve stability, this work presents a design method to enhance the dissipativity of grid-following inverters over a wide frequency range. Based on the dq-domain admittances, the frequency-domain dissipativity affected by different control loops and the time delay are investigated. By designing virtual elements, the dissipativity in different frequencies can be flexibly enhanced. A model-based design criterion is proposed to tune the control parameters following a model-based approach. The design method is presented for a high-power inverter system. The effectiveness of the method is also proved with a down-scaled prototype, which includes simulations, experiments, and dissipativity analysis.