An Improved Voltage Control Strategy Based on Finite-Time Theory for Virtual Synchronous Generator

In this paper, a coordinated DC voltage control strategy is proposed based on the VSG (virtual synchronous generator) method for the VSC-HVDC transmission system to participate in the frequency regulation of the connected weak grid. The voltage and power control capability of the VSC-HVDC is explored to attenuate the rate of change of frequency and to diminish the deviation of frequency. This is realized by the coordinated control of DC voltages at both the sending and the receiving ends with the VSG method. A small-signal model is established to investigate the dynamics of the control system. A tuning method for the selection of control parameters is also discussed in detail. The validity and superiority of the proposed control strategy are tested in the scenarios of sudden load changes and short circuit faults.

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A Novel Approach Using Adaptive Neuro Fuzzy Based Droop Control Standalone Microgrid In Presences of Multiple Sources

International Journal of Renewable Energy Development ◽

10.14710/ijred.9.1.43-51 ◽

2019 ◽

Vol 9 (1) ◽

pp. 43-51

Author(s):

Srinivas Singirikonda ◽

Y.P. Obulesu

Keyword(s):

Control Strategy ◽

Reactive Power ◽

Voltage Control ◽

Synchronous Generator ◽

Droop Control ◽

Renewable Generation ◽

Generation System ◽

Voltage Control Strategy ◽

Neuro Fuzzy ◽

Micro Grid

In this paper, a novel Q/P droop control strategy for regulating the voltage and frequency in Standalone micro grid with multiple renewable sources like solar and wind is presented. The frequency and voltage control strategy is applied to a Standalone micro grid with high penetration of intermittent renewable generation system. Adaptive Neuro-Fuzzy logic Interface system (ANFIS) controller is used for frequency and voltage control for Renewable generation system. Battery energy storage system (BESS) is used to generate nominal system frequency instead of using the synchronous generator for frequency control strategy. A synchronous generator is used to maintain the state of charge (SOC) of the BESS, but it has limited capacity. For Voltage control strategy, we proposed reactive power/active power (Q/P) droop control to the conventional reactive power controller which provides voltage damping effect. The induced voltage fluctuations are reduced to get nominal output power. The proposed model is tested on different cases and results show that the proposed method is capable of compensating voltage and frequency variations occurring in the micro grid with minimal rated synchronous generator. ©2020. CBIORE-IJRED. All rights reserved

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Finite-time disturbance observer–based funnel voltage control strategy for vehicle-to-grid inverter in islanded mode

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1177/09596518211017343 ◽

2021 ◽

pp. 095965182110173

Author(s):

Yuchen Dai ◽

Liyan Zhang ◽

Guofu Liu ◽

Dezhi Xu ◽

Chengshun Yang

Keyword(s):

Control Strategy ◽

Finite Time ◽

Disturbance Observer ◽

Sliding Mode ◽

Tracking Error ◽

Voltage Control ◽

Lyapunov Theory ◽

Voltage Control Strategy ◽

Power Sources ◽

Vehicle To Grid

Based on vehicle-to-grid technology, electric vehicles can be used as power sources in the case of power failure. With the aim to reduce voltage overshoot and improve the anti-disturbance ability of the vehicle-to-grid inverter, a high-performance voltage control strategy based on funnel control and finite-time disturbance observer is developed. First, the dynamic model of the inverter in dq-frame is established, and the lumped disturbance including the unmodeled part is considered. Next, a novel funnel variable is proposed to ensure that the voltage tracking error can be stabilized within the prescribed funnel boundary, and thus enhance the transient performance. Then, a novel finite-time disturbance observer is designed to estimate the lumped disturbance in the system such as load fluctuations, and improve the anti-disturbance ability of the controller. Moreover, the second-order sliding mode differentiator is introduced to estimate the derivative of the virtual control law and eliminate the explosion of complexity problem in the derivation process. Finally, the finite-time stability of the proposed voltage control strategy is analyzed via the Lyapunov theory. The effectiveness of the proposed control strategy is verified by two cases.

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