Robust Frequency and Voltage Stability Control Strategy for Standalone AC/DC Hybrid Microgrid

Asghar, Furqan; Talha, Muhammad; Kim, Sung Hoon

doi:10.3390/en10060760

Cited by 34 publications

(22 citation statements)

References 27 publications

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“…where ρ i , R i , v, and ω i rot refer to air density, rotor radius, wind speed, and rotor speed, respectively. Finally, the dynamic model of the mechanical part of the asynchronous generator is described by (16)…”

Section: Fixed-speed Wind Turbine Generator Modelmentioning

confidence: 99%

“…The paper investigates the sustainability effects of key parameters such as loss coefficients, local loop control dynamics and the number of resources and compares the voltage and current status from a sustainability perspective. Asghar et al [16] developed a new control mechanism based on fuzzy logic and energy storage to control the frequency and voltage of the MG in the islanded mode. In this paper, both battery storage and super-capacitor have been used to improve the MG frequency oscillations and voltage stability, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Assessing the Use of Reinforcement Learning for Integrated Voltage/Frequency Control in AC Microgrids

2020

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The main purpose of this paper is to present a novel algorithmic reinforcement learning (RL) method for damping the voltage and frequency oscillations in a micro-grid (MG) with penetration of wind turbine generators (WTG). First, the continuous-time environment of the system is discretized to a definite number of states to form the Markov decision process (MDP). To solve the modeled discrete RL-based problem, Q-learning method, which is a model-free and simple iterative solution mechanism is used. Therefore, the presented control strategy is adaptive and it is suitable for the realistic power systems with high nonlinearities. The proposed adaptive RL controller has a supervisory nature that can improve the performance of any kind of controllers by adding an offset signal to the output control signal of them. Here, a part of Denmark distribution system is considered and the dynamic performance of the suggested control mechanism is evaluated and compared with fuzzy-proportional integral derivative (PID) and classical PID controllers. Simulations are carried out in two realistic and challenging scenarios considering system parameters changing. Results indicate that the proposed control strategy has an excellent dynamic response compared to fuzzy-PID and traditional PID controllers for damping the voltage and frequency oscillations.

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Section: Fixed-speed Wind Turbine Generator Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessing the Use of Reinforcement Learning for Integrated Voltage/Frequency Control in AC Microgrids

2020

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“…They are widely used in renewable energy generation systems to smooth the output power of wind turbine and PV systems. The super-capacitor, one of the most mature power-type storage devices, is extensively used to stabilize power system fluctuation [32], whose maximum output power (P scmax ) can be expressed as:…”

Section: Distributed Energy Storage Systemmentioning

confidence: 99%

Sizing Hybrid Energy Storage Systems for Distributed Power Systems under Multi-Time Scales

Liu

et al. 2018

Applied Sciences

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Abstract:With the rapid development of industry, more fossil energy is consumed to generate electricity, which increases carbon emissions and aggravates the burden of environmental protection. To reduce carbon emissions, traditional centralized power generation networks are transforming into distributed renewable generation systems. However, the deployment of distributed generation systems can affect power system economy and stability. In this paper, under different time scales, system economy, stability, carbon emissions, and renewable energy fluctuation are comprehensively considered to optimize battery and super-capacitor installation capacity for an off-grid power system. After that, based on the genetic algorithm, this paper shows the optimal system operation strategy under the condition of the theoretical best energy storage capacity. Finally, the theoretical best capacity is tested under different renewable energy volatility rates. The simulation results show that by properly sizing the storage system's capacity, although the average daily costs of the system can increase by 10%, the system's carbon emissions also reduce by 42%. Additionally, the system peak valley gap reduces by 23.3%, and the renewable energy output's fluctuation range and system loss of load probability are successfully limited in an allowable range. Lastly, it has less influence on the theoretical best energy storage capacity if the renewable energy volatility rate can be limited to within 10%.

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“…As a system with various distributed generators, AC and DC loads, and self-adjusting and control capabilities [1,2], the microgrid applies power electronic transformers, which not only enables it to carry out the power transmission and electrical isolation of traditional transformers, but also realizes harmonic and reactive power compensation. The microgrid supports accurate and bidirectional power flow regulations [3][4][5] and has broad application prospects in this field. In [3][4][5], the topology and control strategy of the AC/DC hybrid microgrid is proposed to achieve the reliable and efficient operation of the AC/DC hybrid microgrid.…”

Section: Introductionmentioning

confidence: 99%

“…The microgrid supports accurate and bidirectional power flow regulations [3][4][5] and has broad application prospects in this field. In [3][4][5], the topology and control strategy of the AC/DC hybrid microgrid is proposed to achieve the reliable and efficient operation of the AC/DC hybrid microgrid. In [6], Power Electronics Transformer (PET) topologies for three-phase AC distribution networks were discussed.…”

Section: Introductionmentioning

confidence: 99%

Research on Simplified Model of AC/DC Hybrid Microgrid for Fault Analysis

Yao¹,

Li²,

Qu³

et al. 2020

Electronics

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The AC/DC hybrid microgrid, which takes into account the access requirements of AC and DC sources and loads, optimizes the structure of traditional distribution networks. The application of power electronic transformers as the core of its energy management, with electrical isolation and accurate control of the voltage, current and power flow by the control system, enables the microgrid to achieve a more flexible and stable transmission mode. Because the power electronic transformer combines the power electronic device and the high-frequency transformer, its frequent switching causes the electromagnetic transient simulation to take too long. Therefore, by simplifying control loops and converters, this paper proposes a simplified model for the microgrid system power flow and the dynamic response under exposure to a fault. The mathematical model equivalent simplification method is used in this paper. This method is concise and efficient and does not rely on the performance of a computer or change the program algorithm of the software. The simplified model was built based on PSCAD (Power System Computer Aided Design) simulation software and was carried out under short circuit fault conditions to verify its validity. The comparison of the simulation’s time consumption and accuracy shows that model simplification can significantly improve the simulation speed, with an acceptable error rate, and its dynamic response maintains good consistency with that of the detailed electromagnetic transient model. Therefore, it can be applied to the transient electromagnetic simulation fault analysis of the AC/DC hybrid microgrid.

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Robust Frequency and Voltage Stability Control Strategy for Standalone AC/DC Hybrid Microgrid

Cited by 34 publications

References 27 publications

Assessing the Use of Reinforcement Learning for Integrated Voltage/Frequency Control in AC Microgrids

Assessing the Use of Reinforcement Learning for Integrated Voltage/Frequency Control in AC Microgrids

Sizing Hybrid Energy Storage Systems for Distributed Power Systems under Multi-Time Scales

Research on Simplified Model of AC/DC Hybrid Microgrid for Fault Analysis

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