Control Strategy of Microgrid Based on Distributed Generation

2012 ◽  
Vol 430-432 ◽  
pp. 1277-1280
Author(s):  
Yao Zhao ◽  
Ru Qi Cheng ◽  
Xin Gong ◽  
Geng Shen Zhao

Upon the traditional wind-solar hybrid distributed generation system,a single-phase microgrid experimental system platform has been built based on the DC bus,Z topology was used to increase the energy utilization ratio. On the basic of realizing the maximum power point tracker of the new energy, different microgrid controlling strategy has been designed to apply to the island and grid connected operation mode: in the cases of island running, master slave control mode will be utilized in the system and the battery will be used as the main control unit to provide the reference voltage; on the other hand, a control method which can merge the generation into the grid as much as possible will be adopted in the case of grid connected. By the use of system model, the simulation of the two operation mode switch state and power flow has been done and the feasibility and effectiveness of the control strategy can be guaranteed,it also has been verified by the microgrid experimental platform.

Author(s):  
Qusay Salem ◽  
Jian Xie

<p class="abstract">This paper presents the power flow control between the main grid and the microgrid in low-voltage distribution network using H-bridge inverter. Controlling the real power flow in the line using the H-bridge inverter is investigated by implementing the line current control strategy. The feasibility of the proposed H-bridge inverter and its control strategy is validated by varying the line current reference. Hence, the H-bridge inverter will operate in its inductive or capacitive operation mode depending on the reference current value and the output of the PI controller in the control unit. The control strategy of the microgrid distributed generators has also been investigated in which P/V droop characteristics is applied to the power control of each DG in the microgrid. The effectiveness of the proposed approaches is validated through simulations. </p>


2013 ◽  
Vol 336-338 ◽  
pp. 547-550
Author(s):  
Ji Hong Zhang ◽  
Zhen Kui Wu ◽  
Hua Li ◽  
Han Shan Li

Micro grid may exert adequately distributed generation efficiency, and that wind Photovoltaic and Energy Storage is a key equipment in the micro grid. Aiming at the distributed generation existing intermittence and randomicity characteristic, the paper discussed the micro grid P/Q control method under the connection grid state and the micro grid U/F control method under the disconnection grid state. It also studied the distributed generation parameters variational law under the micro grid different run mode, and built the correlative mathematics model and tested by simulation. The results show: the control strategy ensured the mice grid running stably, and achieved the system anticipative design request, and offered theory foundation for the distributed generation extend application.


2021 ◽  
Vol 2083 (2) ◽  
pp. 022099
Author(s):  
Chengyi Yue ◽  
Binbin Bei

Abstract Reducing the dependence of microgrid upon the communication system and realizing the efficient control of multiple distributed generation of the microgrid are problems that need to be solved urgently. Through the research, based on multiple microgrid operation modes, the peer-to-peer control strategy in microgrid is investigated, and the peer-to-peer control strategy method of microgrid is given for a variety of complex control problems of distributed power According to the peer-to-peer control strategy method, distributed power supply adopts droop control in adjusting distributed power supply in output voltage and frequency; the droop controller has P-f and Q-U droop characteristics. This paper establishes a peer-to-peer control microgrid simulation model, adopts the droop controller designed in this paper to island mode and grid-connected mode, and investigates how the microgrid switches between the two modes. In accordance with Matlab/Simulink simulation outcomes, the research examines frequency, voltage and power changes in distributed generation in the microgrid, and verifies the validity and feasibility of microgrid peer-to-peer control strategy.


2012 ◽  
Vol 516-517 ◽  
pp. 1437-1442
Author(s):  
Qiu Rui Zhang ◽  
Bao Ming Ge ◽  
Da Qiang Bi

At present, the rate of energy utilization is low for the transit regenerative braking on urban rail; most of the energy is consumed by the resistance heating. In this paper, a regenerative braking energy injected-grid device is designed, which makes use of regenerative braking energy and effectively reduce the temperature rise caused by the resistance in the tunnel. The paper describes the composition and the design procedure of regenerative braking energy injected-grid device and presents a control strategy of device. The simulation of the single train model verifies that the stability of DC-bus voltage can be maintained and more power can be feedback to the grid by the proposed device when the train is braking. The feasibility and effectiveness of the proposed control method are validated by the experimental results.


2012 ◽  
Vol 608-609 ◽  
pp. 494-499 ◽  
Author(s):  
Xin Shou Tian ◽  
Yue Hui Huang ◽  
Xiao Yan Xu ◽  
Wei Sheng Wang

In order to improve the frequency stability of grid, new control strategy for wind turbines need to be developed with high wind power penetration. This work analyzes the requirements of frequency control for wind turbines in some countries, and the characteristics and methods of typical frequency control strategy are analyzed. To meet the requirements of frequency control of wind turbine and to improve wind energy utilization efficiency, a method of optimization scheme of frequency control on wind turbine is given in the paper, and the operating curve of wind turbine with the control method is determined, at the same time this work gives a general method about how to determine some key parameters.


Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2047
Author(s):  
Xiangwu Yan ◽  
Chenguang Wang ◽  
Ziheng Wang ◽  
Hongbin Ma ◽  
Baixue Liang ◽  
...  

At present, the installed capacity of photovoltaic-battery energy storage systems (PV-BESs) is rapidly increasing. In the traditional control method, the PV-BES needs to switch the control mode between off-grid and grid-connected states. Thus, the traditional control mode reduces the reliability of the system. In addition, if the system is accidentally disconnected from the grid or the energy storage battery fails to work normally, the DC voltage of the inverter increases or decreases rapidly. To address these two problems, in this paper, a united control strategy is proposed. In the case of grid connection, based on the voltage-frequency controlled VSG strategy, the strategy adjusts the output power of the VSG by changing the position of the primary frequency modulation curve. This method can ensure that, after the system is connected to the grid, excess PV power can be sent to the grid, or power can be absorbed from the grid to charge energy storage. In the off-grid state, the strategy uses FPPT technology and superimposes a voltage component onto the voltage loop to quickly balance the DC power and AC power of the inverter. This strategy can improve the reliability of the system’s power supply if the energy storage fails to work normally. Finally, a PV-BES model was built using MATLAB-Simulink, and the simulation results proved the effectiveness of the proposed strategy.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2422 ◽  
Author(s):  
Triet Nguyen-Van ◽  
Rikiya Abe ◽  
Kenji Tanaka

This paper proposes a digital adaptive hysteresis current control method for multi-functional inverters in a power-flow control device called digital grid router. Each inverter can be controlled in master, grid-connected, or stand-alone modes, which can be specified by the controller. While the popular linear sine-triangle pulse width modulation (SPWM) control technique requires complicated proportional-integral (PI) regulators with an unavoidable time delay, hysteresis current control has a simple structure, fast responses, and robustness due to its independent system of parameters. Since the hysteresis current control method controls the output current stay around the reference current directly, in the multi-functional inverter, the reference output is not given by a current directly. Thus, the reference current used to implement the hysteresis current control in this study is calculated from the given reference voltage or power in each control mode. The controller uses high-speed sampled data at MHz level and is implemented by using a field-programmable gate array (FPGA). Experimental results show good performances of the proposed controller in controlling power exchanges in the digital grid router.


2014 ◽  
Vol 1044-1045 ◽  
pp. 677-680
Author(s):  
Gui Ying Liu ◽  
Yong Guang Gui ◽  
Shi Ping Su ◽  
Qian Luo ◽  
Jiang Wu ◽  
...  

For the different operation mode of micro-grid, an improved droop control method and a parallel inverter was proposed depending on the study of micro-grid inverter. Grid-connected interface contains a series inverter and a parallel inverter, and can be switched to select different work mode. The parallel inverter can eliminate harmonic, compensate three-phase imbalanced current to improve the quality of the power delivered to the utility grid. In islanding operation mode, the improved droop control strategy was applied, where an integral controller was introduced. So it can reduce the inverter output voltage amplitude. Thereby it can restrain circulation and realize the power of self-distribution. The effectiveness and feasibility are verified by the simulation result.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1738
Author(s):  
Jingang Han ◽  
Xin Gu ◽  
Yi Yang ◽  
Tianhao Tang

With the increasing importance of power accumulator batteries in electric vehicles, the accurate characteristics of power accumulator batteries have an important role. In order to evaluate the power accumulator battery, battery charging and discharging is indispensable. In this article, a H-bridge bidirectional DC-DC converter is presented which can charge and discharge the battery with different voltage levels and one of the merits of this topology is that a wide output voltage range can be easily achieved. In the control part, a proportional-integral (PI) control strategy is adopted to ensure a stable and reliable operation of the converter. Furthermore, compared with the PI control strategy, a duty ratio feedforward control is utilized to obtain the rapid current dynamic response. In this article, firstly, the system configuration for battery charging and discharging is introduced, then the operating principles and mathematical model of the DC-DC converter are analyzed and derived. Secondly, for bidirectional DC-DC converters, the PI control method and duty ratio feedforward control method are put forward and designed. Finally, the simulation model is established based on PSIM software and the experiment platform is also built in lab. The results of the simulation and experiment research show that the H-bridge bidirectional DC-DC converter can operate reliably and stably during the charging, discharging and power flow reverse modes. In addition, the dynamic response of the charging and discharging current can also be further improved by introducing the duty ratio feedforward control method.


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