Generator Control Research Articles

Adaptive Inertial Control for Wind Turbine Generators in Fast Frequency Response Based on the Power Reduction Period Assessment

Adaptive Inertial Control for Wind Turbine Generators in Fast Frequency Response Based on the Power Reduction Period Assessment

Backstepping approach for the control of the double-fed asynchronous generator in a wind power system

<p>This paper aims to model and control the dual-fed asynchronous generator (DFIG). The modeling and vector control were simulated using MATLAB, followed by the application of the Backstepping control strategy. A comparative study between two DFIG control strategies, fuzzy logic control (FLC) and Back-stepping control, was conducted. The results for the Backstepping approach are discussed and compared with FLC, highlighting that the Backstepping technique addresses robustness issues regarding variations in operating conditions and internal parameters. Both control strategies are applied to a wind turbine system, and the simulation results and robustness tests are analyzed.</p>

Fuzzy logic control of a permanent magnet synchronous generator integrated in a wind system

This paper deals with the use of a Permanent Magnet Synchronous Generator (PMSG) for the production of wind energy and the injection of the energy produced into a power grid. The objective of this work is to model and simulate the wind energy production system taking into account the problems of the production of electrical energy which are among others: - the problems of maintenance of the generator; - the problems of variations and high wind speed. The contribution of this paper is mainly based on the control strategy of the power generation system based on the Permanent Magnet Synchronous Machine. Then, in order to ensure the real-time tracking of the optimal operating point and to have a maximum production of the electrical power for different wind speeds, we used an FLC speed controller with the aim of increasing this degree of efficiency and improve the performance of our system.

Multi-Modal Compliant Quadruped Robot Based on CPG Control Network

Quadruped robots, with their biomimetic structure, are capable of stable locomotion in complex terrains and are vital in rescue, exploration, and military applications. However, developing multi-modal robots that feature simple motion control while adapting to diverse amphibious environments remains a significant challenge. These robots need to excel at obstacle-crossing, waterproofing, and maintaining stability across various locomotion modes. To address these challenges, this paper introduces a novel leg–fin integrated propulsion mechanism for a bionic quadruped robot, utilizing rapidly advancing soft materials and integrated molding technologies. The robot’s motion is modeled and decomposed using an improved central pattern generator (CPG) control network. By leveraging the control characteristics of the CPG model, global control of the single-degree-of-freedom drive mechanism is achieved, allowing smooth transitions between different motion modes. The design is verified through simulations conducted in the Webots environment. Finally, a physical prototype of the quadruped compliant robot is constructed, and experiments are carried out to test its walking, turning, and obstacle-crossing abilities in various environments. The experimental results demonstrate that the robot shows a significant speed advantage in regions where land and water meet, reaching a maximum speed of 1.03 body lengths per second (bl/s).

Aspects of Relevance of Hybrid Power Plants in Control and Stability of Weak Grids

This paper reviews the possible contributions of Hybrid Power Plants (HPPs) to support weak grids while maintaining the desired system stability. Moving towards a converter-dominant power system with less inherent inertia and distant connections to the nearest synchronous generator, frequency and voltage controls are becoming more critical to ensure the stability of the weak grid. In this regard, state-of-the-art literature is reviewed for frequency and voltage controllers in single-technology power plants, like wind and solar power plants. The contribution of this paper lies in providing a clear overview of available literature in terms of frequency and voltage control stages, regardless of the utilized control method. On the other hand, focus has been put on the increased utilization of HPPs to provide more flexibility, increased availability, and reduced variability through the combination of various sources, i.e., wind, solar, and storage. Furthermore, investigating the specific capabilities and challenges of HPPs, this review shows that very little literature has been conducted on voltage control using HPPs. Finally, the aspect of relevance of HPPs is discussed in the control and stability of modern power systems.

Simulation Analysis of Simulink-based Inverter Controller in Micro-grids

As environmental awareness increases and new energy technologies develop, microgrid systems have garnered significant attention as an important method for operating new energy sources. This trend reflects the growing emphasis on environmental protection. In the process of achieving both independent operation and grid-connected operation, the internal microgrid needs to incorporate an inverter control system equipped with various control methods. The inverter control system is responsible for regulating the inner loop parameters, and the coupling of these parameters will directly impact system stability. The research focus of this article is on microgrid systems that include wind-solar-storage systems. The study primarily employs three control types—constant power control (PQ), virtual synchronous generator control (VSG), and a combination of PQ and VSG control (PQ+VSG)—for simulation analysis to explore system stability. By conducting an in-depth stability analysis, we further understand the characteristics of inverter internal control and grid-connected inverter operation, thereby providing guidance for the design of control systems and ultimately achieving their effective application in power systems.

Low‐frequency oscillation damping strategy for power system based on virtual dual‐input power system stabilizer

AbstractTo keep pace with the construction of the new‐type power system, virtual synchronous generator control, as a classical method of virtual inertia control, has been widely adopted due to its electromechanical characteristics similar to synchronous generator. However, the introduction of rotor motion equations leads to low‐frequency oscillation issues in virtual synchronous generator units similar to synchronous machines. To address this challenge, this paper constructs the Phillips‐Heffron model of the virtual synchronous generator grid‐connected system and analyses the mechanism of low‐frequency oscillation in virtual synchronous generator through the damping torque method. Subsequently, a virtual dual‐input power system stabilizer is proposed by drawing inspiration from the design principles of the traditional dual‐input power system stabilizer to suppress low‐frequency oscillations in the power system. The structure of the virtual dual‐input power system stabilizer is provided, and the phase compensation method is used to optimize the parameters of the virtual dual‐input power system stabilizer. Finally, the effectiveness of the proposed virtual dual‐input power system stabilizer is verified by simulation comparison.

Simulation of Voltage and Frequency Stabilization in PV-Based Microgrids Using Virtual Synchronous Generator Control

In recent years, distributed generation technologies and micro-grids have garnered increasing attention, particularly with the rapid growth of renewable energy sources (RESs) integrated via power electronic converters. As the penetration of RESs in modern power systems rises, voltage and frequency support, traditionally provided by synchronous generators, can be effectively managed by Virtual Synchronous Generator (VSG) control. This paper presents the modeling and analysis of voltage and frequency stability enhancement in a PV-based micro-grid system using VSG control. The micro-grid system under study operates at 400V, 50Hz, and is integrated with a 0.4kV power distribution line. Mathematical models of the VSG control strategy are developed in MATLAB/Simulink. Simulation results demonstrate that VSG control significantly improves the voltage and frequency stability of the PV-based micro-grid system.

Voltage regulation control of three-stage synchronous generator based on modified differential evolution algorithm

Abstract In modern aviation power systems, the dynamic stability of power generation systems has become a major challenge. To tackle issues such as slow response, poor voltage stability, and voltage oscillations in aircraft synchronous generators under sudden load changes, a Proportional-Integral-Derivative (PID) voltage regulator modified using the Differential Evolution (DE) algorithm has been developed. Additionally, the DE algorithm’s convergence speed and robustness are enhanced through the incorporation of directional search strategies and adaptive control parameters. Simulation results demonstrate that the optimized regulator delivers rapid response and minimal overshoot, thereby improving the accuracy and dynamic performance of the voltage regulator. The modified DE algorithm notably accelerates convergence compared to the traditional DE algorithm.

Dual-loop Segmented Piston Trajectory Control of Free Piston Linear Generator based on sliding mode control

Free piston linear generator (FPLG) can be applied as range extender for electrical vehicles to reduce greenhouse gas emissions attributed to its fuel flexibility and ultimate freedom of piston motion. However, FPLG still faces several challenges in control such as misfire and collision due to the eliminate of mechanical crankshaft. To fully utilize the potential of the ultimate freedom of piston motion, this paper presents a novel piston trajectory control strategy which employs the piston trajectory on the entire operation process of FPLG as the control objective. Considering disturbances and high coupling of FPLG, a sliding mode controller is employed to track reference piston trajectory. Additionally, a segmented control strategy is implemented to decouple the control of combustion pressure force and electromagnetic force. In order to ascertain the effectiveness of the proposed controller, a prototype of single-piston FPLG and a corresponding numerical model are constructed. The experimental and simulation results demonstrate the proposed controller shows fast response, precise tracking performance, and good robustness at various reference piston trajectories. Furthermore, the experimental results illustrate that the system can achieve cold start through the seamless transition between operation states and long-term stable operation by the controller.

Control of Virtual Synchronous Generator With Improved Transient Angle Stability Under Symmetric and Asymmetric Short Circuit Fault

Control of Virtual Synchronous Generator With Improved Transient Angle Stability Under Symmetric and Asymmetric Short Circuit Fault

Application of Squirrel Cage Generator Control System Utilizing Direct Torque Control Method as the Shaft Generator in a Seagoing Ship

Application of Squirrel Cage Generator Control System Utilizing Direct Torque Control Method as the Shaft Generator in a Seagoing Ship

Adaptive Neural Control Design for Strict-Feedback Time-Delay Nonlinear Systems Based on Fast Finite-Time Stabilization: A Case Study of Synchronous Generator Systems

This study aims to investigate the finite-time control problem for a class of strict-feedback time-delay nonlinear systems with unknown functions. The control design is based on a fast finite-time practical stability criterion. Unknown nonlinear functions can be estimated using the universal approximation performance of neural networks. Finite-time control design is performed using adaptive backstepping technology. By performing closed-loop stability analyses and choosing appropriate Lyapunov–Krasovskii functionals, all signals in a closed-loop system can be bounded within a finite time. Subsequently, the proposed control method can be applied for the excitation control of synchronous generators. The effectiveness of the proposed method is verified using a numerical model of a single-machine power system.

Comparative Analysis and Improvement of Generalized Droop Control and Virtual Synchronous Generator for Rate of Change of Frequency Constraint and Transient Power Suppression

ABSTRACTSince the microgrid lacks inertia compared to the conventional grid with synchronous generators, the microgrid is unable to address the frequency change issues resulting from the integration of large‐scale distributed generation. Due to the ability to provide virtual inertia, generalized droop control (GDC) and virtual synchronous generator (VSG) control are considered effective solutions for improving frequency regulation. However, in response to external frequency disturbances, the grid‐connected inverters may experience a significant transient active power overshoot caused by GDC and VSG. In this paper, the GDC is used as the fundamental control architecture, and then the small signal models of the GDC and VSG are compared and analyzed under various disturbances. A reduced‐order method for the GDC model is proposed to simplify the analysis of GDC. Additionally, GDC adaptive inertia (GDCAI) and adaptive inertia for operation mode switching (AIOMS) are proposed to mitigate frequency fluctuations and improve active power response. The effectiveness of the two control strategies is verified by MATLAB/Simulink simulation and StarSim hardware‐in‐the‐loop (HIL) experiment.

Variable droop gain frequency supporting control with maximum rotor kinetic energy utilization for wind-storage system

To address the emerging frequency stability issue brought by the large replacement of synchronous generators with renewable generations, wind turbine generators are required to possess frequency-supporting capability. However, existing frequency-supporting control strategies lack the assessment of the frequency support capability of wind turbine generators, leading to degraded control performance under various situations. Aiming to solve this problem, this paper proposes a variable-droop-gain control for wind turbine generators with maximum rotor kinetic energy utilization. Firstly, an analytical relationship was established between droop gain, disturbance scale, and rotor speed. Subsequently, the released energy of the wind turbine generator is evaluated, which equals the difference in the rotor kinetic energy under the initial and the post-disturbance steady-state rotor speed. It was proved that the released kinetic energy cannot exceed a certain proportion of total rotor kinetic energy. Accordingly, a variable initial gain scheme is proposed, which determines the initial droop gain as per the disturbance scale for maximizing the kinetic energy release of wind turbines. Moreover, an additional real-time droop gain adjustment rule is added to prevent the over-deceleration of wind turbines. The simulation results show that the proposed scheme may provide the maximum KE release and effectively improve the system frequency nadir while ensuring the safe operation of wind turbine generators.

Study on improved control strategy of virtual synchronous generator

Virtual synchronous generator (VSG) control technology for photovoltaic, energy storage, wind power, and other new energy to provide flexibility in the grid interface characteristics, is conducive to improving the stability of the power system, and has been widely considered by many scholars. Firstly, an improved VSG control method is proposed through simulation and analysis, which realizes the complete decoupling of the frequency response time constant and the inertia quantity of the active power control loop and reduces the complexity of the parameter design of the VSG system. Secondly, to avoid the frequent action of the VSG system caused by small-scale frequency change perturbation, this study proposes a VSG frequency optimization control method for VSG frequency control with rated angular velocity ωset feedforward composed of multivariate factors when considering a primary frequency regulation dead zone. Thirdly, the impact of VSG parameter design on the system is investigated through the system response characteristics of power scheduling, primary frequency regulation at the grid connection, and the small-signal dynamic characterization of the improved VSG. Finally, Simulation and experimental verification yielded an active power overshoot of 7% and a maximum frequency deviation of 0.17 Hz for the improved system. The improved control method resulted in an improvement of 0.1 s in the frequency response time and a reduction of 0.15 Hz in the oscillation amplitude. The response speed of the improved control method is much better, while the oscillation amplitude is reduced to meet the grid's regulation requirements. The simulation and experimental analysis verify the feasibility of the improved VSG control method.

Adaptive Virtual Synchronous Generator Control Strategy Based on Frequency Integral Compensation

With the increasing proportion of power electronic equipment in the power system, improving the inertia and damping characteristics of the system through virtual synchronous generator (VSG) control technology has become a hot research topic. In terms of adjusting the output frequency, traditional primary frequency modulation control cannot ensure that the output frequency is maintained within the safe operating range when the load disturbance is large, so secondary frequency modulation with the integral link is usually adopted. However, the fixed integral coefficient cannot solve the contradiction between system regulation time and frequency oscillation. In this paper, a strategy of coordinated adaptive control based on the integral coefficient, moment of inertia, and damping coefficient is proposed. According to the offset of frequency and the change rate of the frequency offset, the value of parameters is determined, and the specific parameter setting method is determined. Finally, the correctness of the proposed control strategy is verified on a simulation platform and a semi-physical experimental platform.

Control strategy for Twin-turbine generator stabilized platform based on global linearization of DC-Bus voltage

Abstract The stabilized platform is considered a crucial component for the toolface angle control of rotary steering tools. The twin-turbine generator stabilized platform (TGSP) control system aims to achieve stable voltage control of the turbine generator and servo control of the toolface angle. Existing methods, such as feedback linearization, have significant computational demands and are highly model-dependent, which limits their effectiveness under significant mud flow fluctuations. To address these shortcomings, this paper introduces a linear active disturbance rejection voltage controller (LADRC), using the square of the bus voltage as the state variable to achieve global linearization of the bus voltage. This method reduces dependence on precise mathematical models and enhances both robustness and efficiency. Simulation results demonstrate that the proposed method can achieve high-performance voltage control and servo control, providing a reference for the development of TGSP control systems.

Model predictive control of a brushless cascadedoubly-fed induction generator with torque regulation for stand-alone applications

In this paper, a novel control method for Brushless Cascade Doubly-Fed Induction Generator (BCDFIG) control is proposed by integrating the Model Predictive Control (MPC) and the Direct Torque Control (DTC) methods. In previous studies, the DFIG's torque control has been performed, using different methods to improve power production. Here, direct torque control, assisted by model predictive control, is used to maintain output voltage during a change in wind speed and load. To reduce switching loss in the inverter, the model predictive unit selects the optimized switching vector and sends it to the DTC unit. According to a predefined switching table in each phase interval, the proper switching sequence for controlling the flux and torque for producing a constant output voltage will be selected. This method can be useful for wind farms and everywhere we need constant voltage, especially in stand-alone applications. Also, this proposed method can be used in grid-connected networks for injecting power into the grid or controlling reactive power. For evaluating this control method, in the first step, the BCDFIG setup is simulated in MATLAB software. Then an experimental setup has been realized in the lab to perform some tests. At the end, the obtained experimental results were investigated.

Study of Resistive SFCL for Stability Increase of BTB-VSC-HVDC System Based on Virtual Synchronous Generator Control Strategy

Study of Resistive SFCL for Stability Increase of BTB-VSC-HVDC System Based on Virtual Synchronous Generator Control Strategy