Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Abstract

Abstract:The stable operation of a microgrid is crucial to the integration of renewable energy sources. However, with the expansion of scale in electronic devices applied in the microgrid, the interaction between voltage source converters poses a great threat to system stability. In this paper, the model of a three-source microgrid with a multi master-slave control method in islanded mode is built first of all. Two sources out of three use droop control as the main control source, and another is a subordinate one with constant power control which is also known as real and reactive power (PQ) control. Then, the small signal decoupling control model and its stability discriminant equation are established combined with "virtual impedance". To delve deeper into the interaction between converters, mutual influence of paralleled converters of two main control micro sources and their effect on system stability is explored from the perspective of control parameters. Finally, simulation and analysis are launched and the study serves as a reference for parameter setting of converters in a microgrid.

Research on Large-Signal Stability of DC Microgrid Based on Droop Control

“…From criterion (21), as the droop coefficient R dj decreased, the maximum allowable value of P CPL increased, indicating that the system's large signal stability margin was improved. On this basis, a nonlinear droop control method was proposed to improve the stability margin of the DC microgrid system.…”

“…Compared with criterion (21), if coefficient b is equal to the linear droop coefficient R dj , the maximum allowable value of P CPL in Equation (32) is larger, that is, the system's large signal stability is improved.…”

“…The droop curve should be designed between the start and end points. As the system may oscillate when running near the non-lead point on the droop curve [20,21], the droop curve needs to be smooth, that is, continuous.…”

“…The droop curve should be designed between the start and end points. As the system may oscillate when running near the non-lead point on the droop curve [20,21], the droop curve needs to be smooth, that is, continuous. As shown in Figure 4, the solid line is a conventional droop curve, and the dashed line is the proposed nonlinear droop curve, where the slope gradually decreases as the current increases.…”

A Protection System for Improved Ring-Bus DC Microgrids

“…The less converter stages mean DC microgrids possess less grid losses than AC ones [1], and their control systems are much simpler, because there is no need to take the reactive power balance and frequency control into consideration [2]. In addition, the DC microgrids are more convenient and effective for DC loads, therefore, with the increasing of the DC loads, advantages of DC microgrids are becoming more and more remarkable [3].…”