scholarly journals A Renewable Energy Community of DC Nanogrids for Providing Balancing Services

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7261
Author(s):  
Giuseppe Barone ◽  
Giovanni Brusco ◽  
Daniele Menniti ◽  
Anna Pinnarelli ◽  
Nicola Sorrentino ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Control Strategy ◽  
Power Flow ◽  
Lithium Ion ◽  
Flexible Resources ◽  
Dc Bus ◽  
Adaptive Control Strategy ◽  
Bus Voltage ◽  
Energy Community ◽  
Photovoltaic Plant

The massive expansion of Distributed Energy Resources and schedulable loads have forced a variation of generation, transmission, and final usage of electricity towards the paradigm of Smart Communities microgrids and of Renewable Energy Communities. In the paper, the use of multiple DC microgrids for residential applications, i.e., the nanogrids, in order to compose and create a renewable energy community, is hypothesized. The DC Bus Signaling distributed control strategy for the power management of each individual nanogrid is applied to satisfy the power flow requests sent from an aggregator. It is important to underline that this is an adaptive control strategy, i.e., it is used when the nanogrid provides a service to the aggregator and when not. In addition, the value of the DC bus voltage of each nanogrid is communicated to the aggregator. In this way, the aggregator is aware of the regulation capacity that each nanogrid can provide and which flexible resources are used to provide this capacity. The effectiveness of the proposed control strategy is demonstrated via numerical experiments. The energy community considered in the paper consists of five nanogrids, interfaced to a common ML-LV substation. The nanogrids, equipped with a photovoltaic plant and a set of lithium-ion batteries, participate in the balancing service depending on its local generation and storage capacity.

scholarly journals Inertial and Damping Characteristics of DC Distributed Power Systems Based on Frequency Droop Control

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2418 ◽  
Author(s):  
Liancheng Xiu ◽  
Liansong Xiong ◽  
Ping Yang ◽  
Zhiliang Kang
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Control Strategy ◽  
Power Grid ◽  
Voltage Control ◽  
Droop Control ◽  
Damping Effect ◽  
Distributed Power Systems ◽  
Dc Bus ◽  
Bus Voltage

With high penetration of renewable energy, DC distributed power systems (DDPSs) need to improve the inertia response and damping capacity of the power grid. The effects of main circuit parameters and control factors on the inertia, damping and synchronization of the DDPS were studied in this paper. Firstly, the dynamic model of DDPSs based on frequency droop control is established in the DC voltage control (DVC) timescale. Then, a static synchronous generator (SSG) model is used to analyze the parameters that affect the inertial level, damping effect and synchronization capability of the DDPS. The analysis results show that an optimal design of the frequency droop coefficient and proportional integral (PI) parameters of the DC bus voltage control loop can equivalently change the characteristics of inertia and damping when the frequency droop control strategy is applied to the DC/DC converter and the DC bus voltage control strategy is used in the grid-tied inverter. Simulation results verify the correctness of the conclusions. This paper helps to design an effective control strategy for DDPSs to enhance the inertial level and damping effect of the power grid and to improve the stable operation capability of renewable energy systems.

scholarly journals Nonlinear control strategy of single-phase unified power flow controller

2021 ◽  
Vol 11 (4) ◽  
pp. 2864
Author(s):  
Younes Abouelmahjoub ◽  
Mohamed Moutchou
Keyword(s):  
Nonlinear Control ◽  
Control Strategy ◽  
Power Flow ◽  
Single Phase ◽  
Reactive Power ◽  
Unified Power Flow Controller ◽  
Current Harmonics ◽  
Dc Bus ◽  
Bus Voltage ◽  
Power Flow Controller

In this work we propose a nonlinear control strategy of single-phase unified power flow controller (UPFC), using in order to enhance energy quality parameters of a perturbed single-phase power grid supplying nonlinear loads. The control objectives are: i) The current harmonics and the reactive power compensation, that ensure a satisfactory power factor correction (PFC) at the point of common coupling (PCC); ii) compensation of the voltage perturbations (harmonics and sags of voltage) in order to ensure the desired level, of load voltage, without distortion; iii) DC bus voltage regulation. The considered control problem entails several difficulties including the high system dimension and the strong system nonlinearity. The problem is dealt with by designing a nonlinear controller with structure including three control loops. The inner-loop regulator is designed using the Lyapunov technique to compensate the current harmonics and reactive power. The intermediary-loop regulator is designed using the Backstepping technique to compensate the voltage perturbations. The outer-loop regulator is designed using a linear PI to regulate the DC bus voltage. The control stability is proved theoretically and through simulations, these latter show the effectiveness and strong robustness of the proposed control, and prove that the above-mentioned objectives are achieved.

scholarly journals Dual-Mode Photovoltaic Bidirectional Inverter Operation for Seamless Power Transfer to DC and AC Loads with the Grid Interface

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
M. Srikanth ◽  
B. Pakkiraiah ◽  
Poonam Upadhyay ◽  
S. Tara Kalyani
Keyword(s):  
Distribution System ◽  
Output Voltage ◽  
Power Flow ◽  
Boost Converter ◽  
Power Transfer ◽  
Dual Mode ◽  
Point Tracking ◽  
Dc Bus ◽  
Bus Voltage ◽  
Power Point

This paper develops the photovoltaic bidirectional inverter (BI) operated in dual mode for the seamless power transfer to DC and AC loads. Normal photovoltaic (PV) output voltage is fed to boost converter, but in space application, boost converter is not so preferable. To overcome this, buck and boost converters are proposed in this paper. Duty cycle to this converter is provided with the help of the outcome of the maximum power point tracking (MPPT) controller. This can be implemented by using perturbation and observation method. The MPPT will operate the switch between buck and boost modes. When the output voltage of a PV array is close to the dc bus voltage, then the bidirectional inverter can fulfill both rectification and grid connected mode. To control the power flow between dc bus and ac grid, a dc distribution system is used to regulate the dc bus voltage to a convinced level. Moreover, the bidirectional inverter must fulfill grid connection (sell power) and rectification (buy power) with power factor correction (PFC) to control the power flow between dc bus and ac grid. The simulations and hardware experimental results of a 2.5 kVA circuit are presented to validate the performance of the proposed dual-mode seamless power transfer.

An improved energy management and control strategy for wind water pumping system

2019 ◽  
Vol 41 (14) ◽  
pp. 3921-3935 ◽  
Author(s):  
Olfa Gam ◽  
Riadh Abdelati ◽  
Mahamadou Abdou Tankari ◽  
Mohamed Faouzi Mimouni
Keyword(s):  
Renewable Energy ◽  
Control Strategy ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Storage System ◽  
Energy Storage System ◽  
Pump System ◽  
Pumping System ◽  
Water Pumping ◽  
Battery Energy

This paper deals with an efficient method to ensure an optimal power flow in water pumping system based on renewable energy. In this context, this study aims to find a global supervisory strategy with an optimal adjustment of the DC-bus voltage enhancement. In the proposed study, a firefly algorithm is employed as the key optimizer of the supervisory power exchange in order to improve the different power flows exchanged among the system devices. The water pumping system (WPS) is made up of a wind turbine (WT) required as the principal renewable energy source associated to a battery energy storage system (BSS) to ensure the power supply continuity of a moto-pump system. The models of WPS units and the control strategy are developed using MATLAB software. The simulation results are provided to show the considerable improvement for the system as regards both of voltage stability and the feasibility of power management strategy.

scholarly journals Research on Bus Voltage Control Strategy of Off-grid DC Microgrid

2020 ◽  
Vol 185 ◽  
pp. 01064
Author(s):  
Yilonɡ Kanɡ ◽  
Ningkang Zheng ◽  
Xiangyang Yan ◽  
Huanruo Qi ◽  
Kai Li
Keyword(s):  
Control Strategy ◽  
High Reliability ◽  
Voltage Control ◽  
Droop Control ◽  
Voltage Control Strategy ◽  
Dc Microgrid ◽  
Voltage Quality ◽  
Dc Bus ◽  
Bus Voltage

It is important to achieve stability of bus voltage in control of DC microgrids. In the DC microgrid, the traditional droop control method is usually adopted to stabilize the bus voltage for its high reliability and cost-effectiveness. However, line resistance will reduce the voltage quality of the DC bus in actual situations. In order to improve the voltage quality of the DC bus, a novel bus voltage control strategy based on modified droop characteristic is proposed. Finally, the simulation model of the off-grid DC microgrid with improved droop control strategy is built on PSCAD/EMTDC platform, and the results verify the effectiveness and feasibility of the proposed control strategy.

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