Hardware and Control Implementation of Electric Springs for Stabilizing Future Smart Grid With Intermittent Renewable Energy Sources

In this paper, the details of practical circuit and control implementation of an electric spring for reactive power compensation and voltage regulation of the ac mains are presented. With Hooke´s law published three centuries ago, power electronics-based reactive power controllers are turned into electric springs (ESs) for regulating the ac mains of a power grid. The proposed ES has inherent advantages of: 1) ensuring dynamic load demand to follow intermittent power generation; and 2) being able to regulate the voltage in the distribution network of the power grid where numerous small-scale intermittent renewable power sources are connected. Therefore, it offers a solution to solve the voltage fluctuation problems for future power grids with substantial penetration of intermittent renewable energy sources without relying on information and communication technology. The proof-of-concept hardware is successfully built and demonstrated in a 10-kVA power system fed by wind energy for improving power system stability. The ES is found to be effective in supporting the mains voltage, despite the fluctuations caused by the intermittent nature of wind power.