A novel control algorithm for grid-connected inverters improving power quality using voltage control and virtual impedance

The high share of renewable power generation in the grid system results also in a high share of power electronics that feed the grid and therefore dominate the grid structure and its characteristic. In the past the grid voltage and frequency were formed by synchronous generators in big central power plants. Nowadays this task must be taken by decentralized inverters. In this paper a new control algorithm for grid-supporting inverters is introduced. The control algorithm is capable to emulate virtual output impedance. The simulated and measured inverter output impedance is shown and the results are discussed.