Comparative Study Between Virtual Synchronous Machine and Virtual Impedance Techniques for Two Paralleled Inverters Sharing a Load

The growing penetration of renewable sources of energy, storage systems and other technologies based on power electronics devices in Electric Power Systems (EPS) request changes in the way that those systems are controlled and operated. Power electronics equipment, which do not have natural load sharing behavior, operating together can be harmful for both themselves and the system connected to them. The objective of this paper is to study and compare two of the most recent load-sharing control techniques for power electronics converters. The controls known as Virtual Synchronous Machine and Synchronous-Reference-Frame Virtual Impedance will be analyzed and simulated in PSCAD-EMTDC environment, based on two existing 30 kVA converters in the Laboratory of Power Electronics and Medium Voltage Applications (LEMT-UFRJ). The obtained results confirm that both techniques are efficient and able to share different types of loads in microgrids.