Secondary Control Method for Standalone DC Microgrid with Improved Voltage Regulation, Load Sharing, and Line Loss

2020 ◽  
Author(s):  
Rajneesh Kumar Yadav ◽  
Souradip De ◽  
Soumya Ranjan Sahoo ◽  
Saikat Chakrabarti
Keyword(s):  
Control Method ◽  
Load Sharing ◽  
Voltage Regulation ◽  
Secondary Control ◽  
Dc Microgrid ◽  
Line Loss

scholarly journals Multiagent Based Distributed Control with Time-Oriented SoC Balancing Method for DC Microgrid

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2793 ◽  
Author(s):  
Tao Wu ◽  
Yanghong Xia ◽  
Liang Wang ◽  
Wei Wei
Keyword(s):  
Multiagent System ◽  
Control Method ◽  
Voltage Regulation ◽  
Control Voltage ◽  
Droop Control ◽  
Secondary Control ◽  
Dc Microgrid ◽  
Global Dynamic ◽  
Charging Mode ◽  
Balance Charge

Based on the droop control, voltage regulation at the secondary control is required to eliminate the deviation of the average voltage across the microgrid. Meanwhile, to prevent any of energy storage (ESs) from over-charging or over-discharging, State-of-Charge (SoC) balancing should be added in the secondary control. This paper proposes a distributed secondary control in the DC microgrid based on the multiagent system (MAS). This controller consists of voltage regulation and time-oriented SoC balancing. In voltage regulation, a PI controller adjusts the droop parameters according to the discrepancy between the average voltage and the reference voltage. In SoC balancing, controller operates in charging mode or discharging mode according to changes of the global average SoC. Being different from the conventional method, the time-oriented SoC balancing method is designed to balance charge/discharge time rather than to balance SoC directly. Thus, SoCs reach a consensus only at the last moment when all ES nodes charge or discharge completely. Furthermore, characteristics, global dynamic model, and steady-state analysis of the proposed control method are studied. Finally, MATLAB/Simulink simulations are performed to verify the effectiveness of the proposed control.

scholarly journals Investigation of Adaptive Droop Control Applied to Low-Voltage DC Microgrid

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5356
Author(s):  
Prudhvi Kumar Gorijeevaram Reddy ◽  
Sattianadan Dasarathan ◽  
Vijayakumar Krishnasamy
Keyword(s):  
Power Flow ◽  
Control Method ◽  
Low Voltage ◽  
Experimental Studies ◽  
Load Sharing ◽  
Voltage Regulation ◽  
Primary Objective ◽  
Control Technique ◽  
Droop Control ◽  
Dc Microgrid

In a DC microgrid, droop control is the most common and widely used strategy for managing the power flow from sources to loads. Conventional droop control has some limitations such as poor voltage regulation and improper load sharing between converters during unequal source voltages, different cable resistances, and load variations. This paper addressed the limitations of conventional droop control by proposing a simple adaptive droop control technique. The proposed adaptive droop control method was designed based on mathematical calculations, adjusting the droop parameters accordingly. The primary objective of the proposed adaptive droop controller was to improve the performance of the low-voltage DC microgrid by maintaining proper load sharing, reduced circulating current, and better voltage regulation. The effectiveness of the proposed methodology was verified by conducting simulation and experimental studies.

scholarly journals Robust Control Method for DC Microgrids and Energy Routers to Improve Voltage Stability in Energy Internet

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1622 ◽  
Author(s):  
Haochen Hua ◽  
Yuchao Qin ◽  
Hanxuan Xu ◽  
Chuantong Hao ◽  
Junwei Cao
Keyword(s):  
Power Transmission ◽  
Control Method ◽  
Voltage Regulation ◽  
Normal Operation ◽  
Local Network ◽  
Linear Matrix ◽  
Dc Microgrid ◽  
Voltage Stabilization ◽  
Energy Internet ◽  
Bus Voltage

The energy internet (EI) is a wide area power network that efficiently combines new energy technology and information technology, resulting in bidirectional on-demand power transmission and rational utilization of distributed energy resources (DERs). Since the stability of local network is a prerequisite for the normal operation of the entire EI, the direct current (DC) bus voltage stabilization for each individual DC microgrid (MG) is a core issue. In this paper, the dynamics of the EI system is modeled with a continuous stochastic system, which simultaneously considers related time-varying delays and norm-bounded modeling uncertainty. Meanwhile, the voltage stabilization issue is converted into a robust H ∞ control problem solved via a linear matrix inequality approach. To avoid the situation of over-control, constraints are set in controllers. The problem of finding a balance between voltage regulation performance and constraints for the controllers was also extensively investigated. Finally, the efficacy of the proposed methods is evaluated with numerical simulations.

Decentralized Voltage Balancing and Power Sharing in Islanded Bipolar DC Microgrids

2020 ◽  
Author(s):  
Saman Dadjo Tavakoli
Keyword(s):  
Transfer Functions ◽  
Control Method ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Dc Microgrid ◽  
Voltage Balancing ◽  
Dc Microgrids ◽  
Converter Topology ◽  
Unbalanced Loads

<div>This paper presents a decentralized control scheme for voltage balancing and power sharing in bipolar dc</div><div>microgrids. This relies on utilizing a converter topology which offers three levels of output voltage availability with the key features of boosting the input voltage and balancing the output voltages. This converter makes it possible to further improve the structure of bipolar dc microgrids as it does not require a central voltage balancer. Small-signal analysis is done and system transfer functions are derived. Based on the RGA concept the highly coupled input-output pairs are found which helps with replacing the MIMO control system of the converter by two SISO systems. The appropriate voltage and current controllers are designed based on SISO principles. Moreover, a double droop control method is proposed which fulfills the simultaneous power sharing and voltage regulation of DG units in the host microgrid. The effectiveness of the proposed control strategy is demonstrated through simulation studies conducted on an</div><div>islanded bipolar dc microgrid involving unbalanced loads, while the voltage balancing of the bipolar dc microgrid and the power sharing accuracy are evaluated.</div>

scholarly journals Decentralized Voltage Balancing and Power Sharing in Islanded Bipolar DC Microgrids

2020 ◽  
Author(s):  
Saman Dadjo Tavakoli
Keyword(s):  
Transfer Functions ◽  
Control Method ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Power Sharing ◽  
Dc Microgrid ◽  
Voltage Balancing ◽  
Dc Microgrids ◽  
Converter Topology ◽  
Unbalanced Loads

<div>This paper presents a decentralized control scheme for voltage balancing and power sharing in bipolar dc</div><div>microgrids. This relies on utilizing a converter topology which offers three levels of output voltage availability with the key features of boosting the input voltage and balancing the output voltages. This converter makes it possible to further improve the structure of bipolar dc microgrids as it does not require a central voltage balancer. Small-signal analysis is done and system transfer functions are derived. Based on the RGA concept the highly coupled input-output pairs are found which helps with replacing the MIMO control system of the converter by two SISO systems. The appropriate voltage and current controllers are designed based on SISO principles. Moreover, a double droop control method is proposed which fulfills the simultaneous power sharing and voltage regulation of DG units in the host microgrid. The effectiveness of the proposed control strategy is demonstrated through simulation studies conducted on an</div><div>islanded bipolar dc microgrid involving unbalanced loads, while the voltage balancing of the bipolar dc microgrid and the power sharing accuracy are evaluated.</div>

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