scholarly journals Coordinated Frequency Control Strategy with the Virtual Battery Model of Inverter Air Conditionings

2019 ◽  
Vol 9 (15) ◽  
pp. 3052
Author(s):  
Jiafu Yin ◽  
Dongmei Zhao
Keyword(s):  
Control Strategy ◽  
Frequency Control ◽  
Hierarchical Control ◽  
Frequency Regulation ◽  
Consensus Protocol ◽  
Consensus Control ◽  
Response Characteristics ◽  
Battery Model ◽  
Control Framework ◽  
Control Scheme

Due to the potential of thermal storage being similar to that of the conventional battery, air conditioning (AC) has gained great popularity for its potential to provide ancillary services and emergency reserves. In order to integrate numerous inverter ACs into secondary frequency control, a hierarchical distributed control framework which incorporates a virtual battery model of inverter AC is developed. A comprehensive derivation of a second-order virtual battery model has been strictly posed to formulate the frequency response characteristics of inverter AC. In the hierarchical control scheme, a modified control performance index is utilized to evaluate the available capacity of traditional regulation generators. A coordinated frequency control strategy is derived to exploit the complementary and advantageous characteristics of regulation generators and aggregated AC. A distributed consensus control strategy is developed to guarantee the fair participation of heterogeneous AC in frequency regulation. The finite-time consensus protocol is introduced to ensure the fast convergence of power tracking and the state-of-charge (SOC) consistency of numerous ACs. The effectiveness of the proposed control strategy is validated by a variety of illustrative examples.

scholarly journals A Distributed Hierarchical Control Framework for Economic Dispatch and Frequency Regulation of Autonomous AC Microgrids

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8408
Author(s):  
Shafaat Ullah ◽  
Laiq Khan ◽  
Irfan Sami ◽  
Ghulam Hafeez ◽  
Fahad R. Albogamy
Keyword(s):  
Control Strategy ◽  
Layer Structure ◽  
Single Point ◽  
Hierarchical Control ◽  
Reference Value ◽  
Frequency Regulation ◽  
Control Framework ◽  
Agent Interaction ◽  
Secondary Layer ◽  
Load Perturbations

Motivated by the single point of failure and other drawbacks of the conventional centralized hierarchical control strategy, in this paper, a fully distributed hierarchical control framework is formulated for autonomous AC microgrids. The proposed control strategy operates with a distinct three-layer structure, where: a conventional droop control is adopted at the primary layer; a distributed leaderless consensus-based control is adopted at the secondary layer for active power and, hence, frequency regulation of distributed generating units (DGUs); and the tertiary layer is also based on the distributed leaderless consensus-based control for the optimal power dispatch. Under the proposed strategy, the three constituent control layers work in a coordinated manner. Not only is the load dispatched economically with a negligible power mismatch, but also the frequencies of all the DGUs are regulated to the reference value. However, the frequency regulation is achieved without requiring any central leader agent that has been reported in the contemporary distributed control articles. As compared to the conventional centralized hierarchical control, the proposed strategy only needs local inter-agent interaction with a sparse communication network; thus, it is fully distributed. The formulated strategy is tested under load perturbations, on an autonomous AC microgrid testbed comprising both low-inertia-type (inverter-interfaced) and high-inertia (rotating)-type DGUs with heterogeneous dynamics, and found to successfully meet its targets. Furthermore, it can offer the plug-and-play operation for the DGUs. Theoretical analysis and substantial simulation results, performed in the MATLAB/Simulink environment, are provided to validate the feasibility of the proposed control framework.

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.

The Control Strategy Study of Doubly-Fed Wind Turbine Participated in Frequency Regulation

2012 ◽  
Vol 512-515 ◽  
pp. 788-793
Author(s):  
Xiao Hua Zhou ◽  
Ming Qiang Wang ◽  
Wei Wei Zou
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Large Scale ◽  
Control Strategies ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Strategy Study ◽  
Fuzzy Control Strategy ◽  
Doubly Fed ◽  
System Frequency

Traditional decoupling control strategy of doubly-fed induction generator (DFIG) wind turbine makes little contribution to system inertia and do not participate in the system frequency control, the synchronization of large-scale wind power requires wind turbine have the ability to participate in the regulation of power system frequency. This paper adds a frequency control segment to traditional DFIG wind turbine and considers the doubly-fed wind turbine operating on the state of the super-synchronous speed, by analysis the effect of inertia and proportional control strategies, a fuzzy control strategy which combines the advantages of the former two control strategies is proposed, simulation results show that this control strategy can more effectively improve the system frequency response.

Dynamic Simulation of Blanket Module Maintenance inside Fusion Vacuum Vessel

2014 ◽  
Vol 556-562 ◽  
pp. 1220-1225
Author(s):  
Yan He Zhu ◽  
Lan Ming Guo ◽  
Jie Zhao
Keyword(s):  
Control Strategy ◽  
Hierarchical Control ◽  
Critical Issue ◽  
Vacuum Vessel ◽  
Positioning Accuracy ◽  
Experiment Platform ◽  
Fusion Device ◽  
Remote Maintenance ◽  
Control Scheme ◽  
Essential Problem

The most critical issue of the blanket module remote maintenance operation is to remove or replace the heavy module with high positioning accuracy of 1mm. Located in vacuum vessel (VV) of the nuclear fusion device, the blanket module is weight up to 500kg, thus the grasp and installation of blanket module come to be the essential problem during the maintenance operation. To meet the requirement, we propose a new hierarchical control strategy of rough and fine positioning technology based on combined sensors. The detail procedures and implementation of the control scheme has been carried out successfully on Virtual Robot Experiment Platform to demonstrate the feasibility of the control strategy.

scholarly journals Distributed Operation of Microgrids Considering Secondary Frequency Restoration Based on the Diffusion Algorithm

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3207
Author(s):  
Su-Been Hong ◽  
Thai-Thanh Nguyen ◽  
Jinhong Jeon ◽  
Hak-Man Kim
Keyword(s):  
Distributed Control ◽  
Frequency Control ◽  
Hierarchical Control ◽  
Control Technique ◽  
Frequency Regulation ◽  
Distributed Generations ◽  
System A ◽  
Economic Operation ◽  
Secondary Layer

This paper proposes a distributed control of the microgrid (MG) system based on the diffusion algorithm. Unlike the existing decentralized strategy that focuses on the economic operation of the MG system, the proposed strategy performs secondary frequency regulation in addition to the optimization of the MG system. The hierarchical control technique is employed in this study, where the primary layer is responsible for power control and the secondary layer is responsible for the frequency control and economic operation of the MG system. A tested MG system with four distributed generations (DGs) is considered. Three types of communication topologies are evaluated in this study, which are line, ring, and full topologies. The proposed controller is compared to the conventional consensus controller to show the effectiveness of the proposed diffusion controller. Simulation results show that the proposed diffusion strategy improves the convergence speed of the distributed control, resulting in the improvement of power responses and frequency quality of the MG system. The tested system is implemented in the MATLAB/Simulink environment to show the feasibility of the proposed diffusion controller.

scholarly journals Research on Frequency Fuzzy Adaptive Additional Inertial Control Strategy for D-PMSG Wind Turbine

2019 ◽  
Vol 11 (15) ◽  
pp. 4241
Author(s):  
Mudan Li ◽  
Yinsong Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Control Strategy ◽  
Synchronous Generator ◽  
Frequency Deviation ◽  
Frequency Regulation ◽  
Response Characteristics ◽  
Inertial Response ◽  
Inertial Control ◽  
Fuzzy Adaptive

The traditional additional inertial control (T-AIC) strategy can provide frequency support for the directly-driven wind turbine with a permanent magnet synchronous generator (D-PMSG). However, due to the fixed control coefficients, the frequency modulation effect is poor under load and wind speed disturbances. In order to improve the frequency transient response of D-PMSG, a fuzzy adaptive additional inertial control strategy (FA-AIC) is proposed in this paper. A simplified D-PMSG model is established for the complexity and low calculation speed. A single-machine grid-connected system composed of a D-PMSG and an equivalent synchronous generator set (ESGS) is taken as the background and analysis of the principle of T-AIC. The proportional and derivative coefficient initial values in T-AIC are tuned by simulating the static characteristics and inertial response characteristics of the conventional synchronous generator set, and fuzzy control technology is introduced to adjust the proportional and derivative coefficients adaptively based on the frequency deviation and the frequency deviation change rate under load or wind speed disturbances. The simulation verification indicates that T-AIC, kinetic energy (KE)-based gain-AIC and FA-AIC all can utilize the D-PMSG additional inertial response to provide frequency support for grid-connected systems. Compared with T-AIC and KE-based gain-AIC, the proposed FA-AIC can not only provide more effective frequency support during load disturbances, but also suppress the frequency fluctuation caused by the wind speed variation and displays a better dynamic frequency regulation effect.

scholarly journals Consensus Control of Distributed Energy Resources in a Multi-Bus Microgrid for Reactive Power Sharing and Voltage Control

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2710 ◽  
Author(s):  
Li Yu ◽  
Di Shi ◽  
Guangyue Xu ◽  
Xiaobin Guo ◽  
Zhen Jiang ◽  
...  
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Hierarchical Control ◽  
Voltage Control ◽  
Power Sharing ◽  
Consensus Control ◽  
Distributed Generator ◽  
Distributed Generators ◽  
Control Framework ◽  
Major Factors

The hierarchical control architecture, including layers of primary, secondary and tertiary controls, is becoming the standard operating paradigm for microgrids (MGs). Two major factors that limit the adoption of existing hierarchical control in microgrid are the low accuracy in reactive power sharing and the requirement for complex communication infrastructure. This paper addresses this problem by proposing a novel distributed primary and secondary control for distributed generators dispersed in a multi-bus microgrid. The proposed method realizes voltage control and accurate reactive power sharing in a distributed manner using minimum communication. Each distributed generator only needs its own information and minimum information from its neighboring units. Topology of the network can be flexible which supports the plug-and-play feature of microgrids. In a distribution system, high R/X ratio and system imbalance can no longer be neglected and thus the sequence component analysis and virtual impedance are implemented in the proposed control framework. The proposed framework is validated by simulation results on a MG testbed modified from the IEEE 13-bus distribution system.

Automating lane changes and collision avoidance on highways via distributed agreement

2019 ◽  
Vol 67 (12) ◽  
pp. 1047-1057
Author(s):  
Fabio Molinari ◽  
Aaron Grapentin ◽  
Alexandros Charalampidis ◽  
Jörg Raisch
Keyword(s):  
Control Strategy ◽  
Autonomous Vehicles ◽  
Optimal Trajectory ◽  
Hierarchical Control ◽  
Lane Changes ◽  
The Road ◽  
Vehicle Communication ◽  
Vehicle To Vehicle ◽  
Control Scheme ◽  
On The Road

Abstract This work presents a distributed hierarchical control strategy for fleets of autonomous vehicles cruising on a highway with diverse desired speeds. The goal is to design a control scheme that can be employed in scenarios where only vehicle-to-vehicle communication is available and where vehicles need to negotiate and agree on their positions on the road. To this end, after reaching an agreement on the lane speed with other traffic participants, each vehicle decides whether to keep cruising along the current lane or to move into another one. In the latter case, it negotiates the entry point with others by taking part in a distributed auction. An onboard controller computes an optimal trajectory transferring the vehicle with agreed velocity to the desired lane while avoiding collisions.

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