Coordinated Control of a Wind Turbine and Battery Storage System in Providing Fast-Frequency Regulation and Extending the Cycle Life of Battery

A two-layer control strategy for the participation of multiple battery energy storage systems in the secondary frequency regulation of the grid is proposed to address the frequency fluctuation problem caused by the power dynamic imbalance between the power system and load when a large number of new energy sources are connected to the grid. A comprehensive allocation model based on area regulation requirement (ARR) signals and area control error (ACE) signals is proposed to obtain the total output of the secondary frequency modulation (FM) demand with a higher degree of adaptation when the FM units respond to the automatic generation control command, and the total output is reasonably allocated to each FM unit by using the two-layer control. Considering the dynamic fluctuation of the grid frequency, the fluctuation is dynamically suppressed in real-time by applying model predictive control to successfully forecast the frequency deviation while realizing the deviation-free correction in the frequency dynamic correction layer. The optimal power distribution of FM units based on the distributed control concept, as well as the power depth of each unit, are coordinated in the equalization control layer while keeping a decent battery charge level. Finally, in Matlab/Simulink, the proposed control approach is simulated and validated. The findings show that the suggested control approach can suppress frequency difference fluctuation, keep the battery charged, and reduce the unit’s FM loss.

Section: Objective Function and Constraint Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Two-Layer Control Strategy for the Participation of Energy Storage Battery Systems in Grid Frequency Regulation

Zhang,

Xin,

Wang

et al. 2024

“…One of the suggested methods is to assume that the BESSs release the same energy as that released by SKE from VSWTs to cover the power loss in a certain period. That is, the FFR is supported by both BESSs and DFIG-VSWTs [23]. At the rated rotor speed, the released SKE ∆E WTG_rated from the DFIG-VSWT is:…”

Section: Dimensioning Of the Besss Capacitymentioning

confidence: 99%

Coordinated Frequency Regulation between DFIG-VSWTs and BESS Hybrid Systems

Phung,

Wu,

Pham

2024

As the utilization of wind power systems continues to increase, reducing overall system inertia, there is a consequential negative impact on the power system’s ability to regulate frequency. Consequently, this study focuses on examining the fast-frequency regulation in high penetration of wind power, especially doubly fed induction generators—the most commonly installed wind turbine type, and an energy storage system installed in the wind farm. This study proposes a coordinated control of wind turbine generators and battery energy storage systems that provides fast-frequency regulation to the system while simultaneously ensuring the safety of the battery. Firstly, the fast-frequency regulation capability of the wind turbine will be studied. Secondly, primary frequency control of the battery energy storage system considering adaptive droop control based on state of charge is proposed to prevent both over-charging and over-discharging of the battery. Finally, this study proposed a coordinated fast-frequency regulation approach for the hybrid wind-storage system, which is evaluated under various wind speed scenarios. This approach involves a detailed analysis of the operational characteristics of the wind turbine generators to ensure optimal performance. The proposed method is validated through simulation using a MATLAB model of the wind-storage system, and comparative results with alternative control methods confirm the effectiveness of the proposed approach in raising the frequency nadir and avoiding the secondary frequency dip.

“…Researchers in reference [43] explore the application of a BESS to smooth the power output from wind turbines, utilizing a fuzzy logic power control strategy. Lastly, reference [44] presents a coordinated control scheme for WTGs and BESSs that not only provides fast frequency regulation (FFR) to the AC system but also extends the battery's cycle life.…”

Section: Introductionmentioning

confidence: 99%

Smoothing Intermittent Output Power in Grid-Connected Doubly Fed Induction Generator Wind Turbines with Li-Ion Batteries

Behabtu,

Vafaeipour,

Kebede

et al. 2023

Wind energy is an increasingly important renewable resource in today’s global energy landscape. However, it faces challenges due to the unpredictable nature of wind speeds, resulting in intermittent power generation. This intermittency can disrupt power grid stability when integrating doubly fed induction generators (DFIGs). To address this challenge, we propose integrating a Li-ion battery energy storage system (BESS) with the direct current (DC) link of grid-connected DFIGs to mitigate power fluctuations caused by variable wind speed conditions. Our approach entails meticulous battery modeling, sizing, and control methods, all tailored to match the required output power of DFIG wind turbines. To demonstrate how well our Li-ion battery solution works, we have developed a MATLAB/Simulink R2022a version model. This model enables us to compare situations with and without the Li-ion battery in various operating conditions, including steady-state and dynamic transient scenarios. We also designed a buck–boost bidirectional DC-DC converter controlled by a proportional integral controller for battery charging and discharging. The battery actively monitors the DC-link voltage of the DFIG wind turbine and dynamically adjusts its stored energy in response to the voltage level. Thus, DFIG wind turbines consistently generate 1.5 MW of active power, operating with a highly efficient power factor of 1.0, indicating there is no reactive power produced. Our simulation results confirm that Li-ion batteries effectively mitigate power fluctuations in grid-connected DFIG wind turbines. As a result, Li-ion batteries enhance grid power stability and quality by absorbing or releasing power to compensate for variations in wind energy production.