This paper deals with the problem of voltage security in microgrids. In general, voltage security is an issue for power systems, where the lack of reactive power is a concern. For microgrids a complexity is imposed, since frequency and voltage level deviations may take place by the operation of droop-controlled inverters. This paper incorporates the load margin calculation into a microgrid stru...

We demonstrate that the efficiency droop phenomenon in multiple quantum well InGaN/GaN light-emitting diodes (LEDs) may be connected to the current crowding effect. A numerical model of internal quantum efficiency calculation is presented that takes into account nonuniform lateral carrier injection in the active region. Based on this model, we examine the effect of current crowding on the effic...

We investigate the effect of internal electric field in InGaN well layer of InGaN/GaN multiple quantum well light-emitting diodes (LEDs) on efficiency droop behavior. The simulation results show that the internal electric field in InGaN well layers of Ga-polar LEDs is same as the direction of external electric field by forward bias voltage, resulting in a strong efficiency droop. However, N-pol...

This paper presents a new intelligent control strategy for DC microgrid in islanded operation mode based on droop control method. The DC microgrid under study included a Wind Turbine Generator (WTG), photovoltaic (PV), battery energy storage system (BESS) and a linear resistive load. According to the proposed method, each of distributed generation (DG) sources and BESS can be deployed independe...

We investigated the efficiency droop and polarization-induced internal electric field of InGaN blue light-emitting diodes (LEDs) grown on silicon(111) and c-plane sapphire substrates. The efficiency droop of the LED sample grown on silicon substrates was considerably lower than that of the identically fabricated LED sample grown on sapphire substrates. Consequently, the LED on silicon showed hi...

Electric grid is vulnerable to power imbalance and inertia the grid's response overcome such disturbance. Augmentation of electronic converter based renewable energy technologies like Photovoltaic Generators (PVG) batteries in utility significantly reduces inertia. Inertia degradation indicated by sharp Rate Change Frequency (ROCOF) events due any component failure or imbalance. Fixed gain feed...

Comprehensive analysis of Distributed Energy Resources (DER) integration requires tools that provide computational power and flexibility. In this context, throughout this paper PHIL simulations are performed to emulate the energy management system of a real microgrid including a diesel synchronous machine and inverter-based sources. Moreover, conventional frequency and voltage droops were incor...