Hierarchical control strategy of grid-connected DC microgrids

2016 ◽  
Author(s):  
Xiaoliang Yang ◽  
Fen Tang ◽  
Xuezhi Wu ◽  
Xinmin Jin
Keyword(s):  
Control Strategy ◽  
Hierarchical Control ◽  
Dc Microgrids

scholarly journals Smooth reference modulation based protection of fault current limiting DC/DC converters

2020 ◽  
pp. 002029402095245
Author(s):  
Hooman Noroozi ◽  
Iman Sadeghkhani
Keyword(s):  
Control Strategy ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Control Level ◽  
Cost Effective ◽  
Fault Current ◽  
Primary Control ◽  
Dc Microgrids ◽  
Fault Ride Through ◽  
Current Limiting

Low voltage DC microgrids have been gaining great attention for the integration of renewable energy source and energy storage units, and electronic loads. DC microgrids are commonly controlled using the hierarchical control strategy (HCS) to provide flexible operation in both grid-connected and islanded modes. The HCS relies on proportional-integral (PI) controllers and employs the droop control strategy. To improve the fault ride-through of HCS based extra low voltage DC microgrids, this paper proposes a simple, accurate, and cost-effective current limiting strategy. The proposed control system based scheme modulates the current reference of the primary control level of HCS during an overcurrent condition using the smooth set point automatic adjustment with correction enabled technique. It properly protects the semiconductor switches of interface voltage-sourced DC-DC converters by accurate limiting their inductor currents. The main advantage of the proposed scheme is that it is implemented in the available PI controller based primary control level of the HCS. Also, it does not require the converter and load data. Several case studies performed in MATLAB/Simulink environment are presented to demonstrate the superior ability of this scheme for limiting fault current in different scenarios compared to conventional current limiters.

scholarly journals A Bus-Sectionalized Hybrid AC/DC Microgrid: Concept, Control Paradigm, and Implementation

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3508
Author(s):  
Jing Li ◽  
Hongda Cai ◽  
Pengcheng Yang ◽  
Wei Wei
Keyword(s):  
Hierarchical Control ◽  
Mode Switching ◽  
Stable Operation ◽  
Service Reliability ◽  
Test Results ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Operation Modes ◽  
Control Paradigm ◽  
Operational Data

In the last several years, the coordination control of hybrid AC/DC microgrids (HMGs) has been gaining increasingly more attention. However, most of these discussions are focused on single-bus HMGs whose AC or DC bus is not sectionalized by AC or DC breakers. Compared with these single-bus HMGs, the bus-sectionalized HMG has more flexible topologies, more diverse operation modes, and consequently higher service reliability. However, meanwhile, these benefits also bring challenges to the stable operation of bus-sectionalized HMGs, particularly for mode switching. Relying on the national HMG demonstrative project in Shaoxing, China, this paper makes efforts to present the hierarchical control paradigm of a typical bus-sectionalized HMG toward standardization. The test results demonstrate that the proposed system provides seamless switching and uninterrupted power supply without controller reconfiguration among different operation modes. The operational data are also brought forth and analyzed to provide significant and useful experiences for designing and developing similar HMGs in the future.

Hierarchical energy management strategy considering switching schedule for a dual-mode hybrid electric vehicle

2021 ◽  
pp. 095440702110297
Author(s):  
Hui Liu ◽  
Rui Liu ◽  
Riming Xu ◽  
Lijin Han ◽  
Shumin Ruan
Keyword(s):  
Fuel Consumption ◽  
Energy Management ◽  
Control Strategy ◽  
Power Distribution ◽  
Hybrid Electric Vehicle ◽  
Hierarchical Control ◽  
Management Problem ◽  
Energy Management Strategy ◽  
Dual Mode ◽  
Hybrid Electric

Energy management strategies are critical for hybrid electric vehicles (HEVs) to improve fuel economy. To solve the dual-mode HEV energy management problem combined with switching schedule and power distribution, a hierarchical control strategy is proposed in this paper. The mode planning controller is twofold. First, the mode schedule is obtained according to the mode switch map and driving condition, then a switch hunting suppression algorithm is proposed to flatten the mode schedule through eliminating unnecessary switch. The proposed algorithm can reduce switch frequency while fuel consumption remains nearly unchanged. The power distribution controller receives the mode schedule and optimizes power distribution between the engine and battery based on the Radau pseudospectral knotting method (RPKM). Simulations are implemented to verify the effectiveness of the proposed hierarchical control strategy. For the mode planning controller, as the flattening threshold value increases, the fuel consumption remains nearly unchanged, however, the switch frequency decreases significantly. For the power distribution controller, the fuel consumption obtained by RPKM is 4.29% higher than that of DP, while the elapsed time is reduced by 92.53%.

scholarly journals Hierarchical Control in Islanded DC Microgrids With Flexible Structures

2020 ◽  
pp. 1-14
Author(s):  
Pulkit Nahata ◽  
Alessio La Bella ◽  
Riccardo Scattolini ◽  
Giancarlo Ferrari-Trecate
Keyword(s):  
Hierarchical Control ◽  
Flexible Structures ◽  
Dc Microgrids

scholarly journals A Novel Hierarchical Control Strategy for Low-Voltage Islanded Microgrids Based on the Concept of Cyber Physical System

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Reactive Power ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Physical Layer ◽  
Cyber Physical System ◽  
Droop Control ◽  
Control Effect ◽  
Consensus Control

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.

Integrated Nonlinear Hierarchical Control and Management of Hybrid AC/DC Microgrids

2021 ◽  
pp. 1-12
Author(s):  
Mojtaba Biglarahmadi ◽  
Abbas Ketabi ◽  
Hamid Reza Baghaee ◽  
Josep M. Guerrero
Keyword(s):  
Hierarchical Control ◽  
Dc Microgrids ◽  
Control And Management

scholarly journals Multidimensional Optimal Droop Control for DC Microgrids in Military Applications

2018 ◽  
Vol 8 (10) ◽  
pp. 1966 ◽  
Author(s):  
Kaitlyn Bunker ◽  
Michael Cook ◽  
Wayne Weaver ◽  
Gordon Parker
Keyword(s):  
Control System ◽  
Control Strategy ◽  
System Reliability ◽  
Droop Control ◽  
Hardware In The Loop ◽  
Dc Microgrids ◽  
Military Applications ◽  
Bus Voltage ◽  
Solar Resource

Reliability is a key consideration when microgrid technology is implemented in military applications. Droop control provides a simple option without requiring communication between microgrid components, increasing the control system reliability. However, traditional droop control does not allow the microgrid to utilize much of the power available from a solar resource. This paper applies an optimal multidimensional droop control strategy for a solar resource connected in a microgrid at a military patrol base. Simulation and hardware-in-the-loop experiments of a sample microgrid show that much more power from the solar resource can be utilized, while maintaining the system’s bus voltage around a nominal value, and still avoiding the need for communication between the various components.

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