Droop Control of Low-voltage Microgrids With Voltage Compensation

Author(s):  
Bo Xie ◽  
Hailiang Hou ◽  
Yun Cheng
Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi

Based on the concept of cyber physical system (CPS), a novel hierarchical control strategy for islanded microgrids is proposed in this paper. The control structure consists of physical and cyber layers. It’s used to improve the control effect on the output voltages and frequency by droop control of distributed energy resources (DERs), share the reactive power among DERs more reasonably and solve the problem of circumfluence in microgrids. The specific designs are as follows: to improve the control effect on voltages and frequency of DERs, an event-trigger mechanism is designed in the physical layer. When the trigger conditions in the mechanism aren’t met, only the droop control (i.e., primary control) is used in the controlled system. Otherwise, a virtual leader-following consensus control method is used in the cyber layer to accomplish the secondary control on DERs; to share the reactive power reasonably, a method of double virtual impedance is designed in the physical layer to adjust the output reactive power of DERs; to suppress circumfluence, a method combined with consensus control without leader and sliding mode control (SMC) is used in the cyber layer. Finally, the effectiveness of the proposed hierarchical control strategy is confirmed by simulation results.


2021 ◽  
Author(s):  
Mohammadreza Nabatirad ◽  
Reza Razzaghi ◽  
Behrooz Bahrani

The conventional droop control is a widely-used technique in load sharing among Distributed Generator (DG) units in islanded DC Microgrids (MGs). This method provides Plug-and-Play (PnP) capability for DG units; however, poor load sharing accuracy and unregulated voltage are two shortcomings of that. This article proposes a novel control system in islanded DC MGs to provide simultaneous regulated voltage and accurate load sharing. The method utilizes a modified droop control technique in a decentralized manner. The proposed control system injects a superimposed AC voltage to the network that carries a frequency proportional to the master DG unit output current. The injected voltage adjusts an added a term to the conventional droop control named as the voltage compensation term in order to cancel voltage changes. This term adjusts terminal voltage of DG units proportional to the frequency of the superimposed AC voltage. The performance of the proposed control system is validated via a set of simulation studies using PLECS, and the experimental results confirm the viability and feasibility of the proposed control system.


2019 ◽  
Vol 2019 (16) ◽  
pp. 3056-3061 ◽  
Author(s):  
Sucheng Liu ◽  
Zhongpeng Li ◽  
Wenjie Liu ◽  
Xiaodong Liu

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Lei Chen ◽  
Hongkun Chen ◽  
Jun Yang ◽  
Huiwen He

Considering the rapid development of high temperature superconducting (HTS) materials, superconducting power applications have attracted more and more attention in the power industry, particularly for electrical systems including renewable energy. This paper conducts experimental tests on a voltage compensation type active superconducting fault current limiter (SFCL) prototype and explores the SFCL’s application in a permanent-magnet synchronous generator- (PMSG-) based wind turbine system. The SFCL prototype is composed of a three-phase air-core superconducting transformer and a voltage source converter (VSC) integrated with supercapacitor energy storage. According to the commissioning test and the current-limiting test, the SFCL prototype can automatically suppress the fault current and offer a highly controlled compensation voltage in series with the 132 V electrical test system. To expand the application of the active SFCL in a 10 kW class PMSG-based wind turbine system, digital simulations under different fault cases are performed in MATLAB/Simulink. From the demonstrated simulation results, using the active SFCL can help to maintain the power balance, mitigate the voltage-current fluctuation, and improve the wind energy efficiency. The active SFCL can be regarded as a feasible solution to assist the PMSG-based wind turbine system to achieve low-voltage ride-through (LVRT) operation.


2013 ◽  
Vol 732-733 ◽  
pp. 1354-1357
Author(s):  
Shi Wang Yang ◽  
Peng Li ◽  
Chang Wang ◽  
Jia Ming Li

How to ensure the security, stability and economic operation of microgrid in different operation modes is a difficult problem of microgrid research. There is active power and reactive power coupling in the regulation of frequencies and voltages because of the line parameter characteristics of microgrid. The defect of the traditional active power-frequency, reactive power-voltage droop control is analyzed and a novel decoupling droop control method for low voltage microgrid is proposed in this paper. At last, the multiple feedback loop control strategy for inverters on the basis of this proposed method and a microgrid simulation model are established. The comparative analysis between the new method and the traditional method based on the simulation results can prove that the proposed control method is simple in design, and it can assure an excellent power quality and realize the reasonable distribution of active power and reactive power between distributed generations.


Sign in / Sign up

Export Citation Format

Share Document