Modelling and Control Strategies of Microgrid in Grid-Connected and Islanded Operation Modes - Part I: Active Power Sharing and Frequency Control

In recent years, the utilization of renewable energy resources has promoted more and more microgrid developed. The microgrid consists of distributed generations (DGs) associate with distributed energy resources (DERs), which are normally located next to the customer and provide electric power at distributed voltage level. However, when a large number of DGs were connected to the AC power grid, it can cause power quality, grid security and stability issues. This paper presents an improved P-f droop control strategy using the reciprocal characteristic to improve the stability performance. Based on simulation analyses with Matlab/Simulink, the results show that the presented droop control strategy has good effects in grid-connected and islanded mode, and during operation mode transitions