Permanent Magnet Synchronous Generator Wind Research Articles

A Parameter-Adaptive Method for Primary Frequency Regulation of Grid-Forming Direct-Drive Wind Turbines

When wind turbines contribute to system frequency support using virtual synchronous generator (VSG) control, conventional VSG methods often fall short of meeting operational demands, particularly in terms of inertia and frequency support. In this study, considering both the frequency regulation and dynamic performance of VSG, a novel parameter design method that enhances frequency modulation capabilities is proposed in this paper. Initially, VSG control is integrated into the grid-side converter of a direct-drive permanent magnet synchronous generator (D-DPMSG) wind turbine. A small-signal model of the D-DPMSG-VSG active power is then formulated to analyze how the moment of inertia and damping coefficient impact system stability. Subsequently, ensuring that system parameter constraints are met, the key parameters of VSG are adaptively designed to dynamically adjust the system’s frequency and output power during transient responses. Finally, simulation results based on D-DPMSG-VSG in MATLAB/Simulink validated the feasibility, effectiveness, and advantages of the proposed parameter-adaptive VSG control strategy for enhancing the frequency modulation (FM) performance of wind turbines.

A Novel Adaptive Third-Order Continuous Super-Twisting Controller of a Five Phase Permanent Magnet Synchronous Wind Generator

The aim of this research is to enhance the control of a Wind Energy Generating System (WEGS) incorporating a Five-phase Permanent Magnet Synchronous Generator (5 ph-PMSG) and addressing operational challenges in the presence of disturbances. The commonly employed Second-Order Super-Twisting Controller (SOSTC), with constant gains, has limitations, including uncertainties, significant transient state errors, and chattering effects, hindering its practical applicability. To overcome these drawbacks, the study proposes the application of an Adaptive Third-Order Continuous Super-Twisting Control (ATOCSTC). This novel approach integrates a third-order sliding mode surface, a smoothly continuous switching control term, and an adaptation law. Unlike the conventional SOSTC using discontinuous “sign” functions, ATOCSTC dynamically adjusts gains using tangent hyperbolic functions, providing a continuous and effective control mechanism. Comparative analysis with the conventional SOSTC under various disturbances such as wind speed fluctuations, parameter variations, and Grid Voltage Sag (GVS), reveals significant improvements with ATOCSTC. Notably, ATOCSTC leads to a 75% reduction in power ripples for grid active power and a 40.38% reduction for grid reactive power. These findings underscore the superior performances obtained with the proposed ATOCSTC in WEGS.

Nonlinear Controller-Based Mitigation of Adverse Effects of Cyber-Attacks on the DC Microgrid System

Cyber-attacks have adverse impacts on DC microgrid systems. Existing literature shows plenty of attack detection methods but lacks appropriate mitigation and prevention approaches for cyber-attacks in DC microgrids. To overcome this limitation, this paper proposes a novel solution based on a nonlinear controller to mitigate the adverse effects of various cyber-attacks, such as distributed denial of service attacks and false data injection attacks, on various components of a DC microgrid system consisting of a photovoltaic power source, a permanent magnet synchronous generator-based variable speed wind generator, a fuel cell, battery energy storage, and loads. To demonstrate the effectiveness of the proposed solution, single and repetitive cyber-attacks on specific components of the microgrid have been considered. An index-based quantitative improvement analysis for the proposed control method has been made. Extensive simulations have been performed by the MATLAB/Simulink V9 software. Simulation results demonstrate the effectiveness of the proposed nonlinear controller-based method in mitigating the adverse effects of cyber-attacks. Moreover, the performance of the proposed method is better than that of the proportional-integral controller. Due to the simplicity of the proposed solution, it can easily be implemented in real practice.

Permanent magnet wind generators: control strategies to manage voltage unbalances

The paper presents four different control strategies for grid connected voltage source inverters, devoted to the interface of permanent magnet synchronous wind generators with the distribution network. A common dq-axes control is compared with two modified controls in the dq frame which take into account also negative sequence components of voltages, and currents and a control approach in the stationary αβ frame which reduces the computational complexity of the control itself. An ATPDraw model of a 2 MW wind generator has been developed and employed for simulating the responses of the four control schemes to voltage unbalances and voltage dips. The improved control strategies have shown better performances in terms of reduction of 100 Hz oscillating power components during network voltage unbalances

Research on model reference adaptive sliding mode control strategy for permanent magnet synchronous wind generator

Research on model reference adaptive sliding mode control strategy for permanent magnet synchronous wind generator

Grid Forming Fast Frequency Response for PMSG-Based Wind Turbines

Electric power systems are undergoing a rapid transition from fuel-based generation using synchronous generators to renewable generation interfaced by power electronics. In this context, a key challenge is using renewable generation with limited controllability to contribute to power system stability. In this work, we investigate grid-forming control of permanent magnet synchronous generator (PMSG) wind turbines. The proposed control and curtailment strategy supports the entire spectrum of standard functions of grid-following (e.g. maximum power point tracking (MPPT) and grid-forming control (e.g., primary frequency control) without explicit mode switching. A detailed case study is used to compare the performance of the proposed control at operating points corresponding to MPPT and frequency control with standard grid-forming and grid-following controls. The results demonstrate that (i) the proposed energy balancing grid forming control is self-synchronizing in MPPT mode, (ii) the (limited) energy storage and controllability of wind turbines can be adequately utilized to provide grid support, and (ii) the proposed control exhibits good performance under variable wind speeds and does not result in a significant increase of wind turbine fatigue loads.

Direct-Driven PMSG Wind Turbines: Adaptive Super Twisting Algorithm Control Approach

This paper deals with the development of a robust nonlinear control strategy for direct-driven Permanent Magnet Synchronous Generator (PMSG) wind turbines. First-Order Sliding Mode Controllers (FOSMC) are commonly used in such systems to regulate generator rotational speed and optimize power extraction; however, they encounter significant drawbacks, notably the undesirable chattering effect and the necessity for measuring additional system states, leading to increased complexity and implementation costs. In addressing these issues, an effective control technique based on an Adaptive Super-Twisting Algorithm (ASTA) has been proposed. This algorithm not only mitigates the chattering effect but also offers a more cost-effective implementation by incorporating online gains adaptation to accommodate the unpredictable nature of wind speeds. The proposed control technique has been evaluated in MATLAB/Simulink through model-in-the-loop simulations; demonstrating superior performance compared to classical FOSMC and STA controllers under various scenarios.

Demagnetization effects of surface-mounted permanent magnet synchronous wind generator

To prevent fossil resources from being depleted and protect the natural balance, renewable resources come to the forefront as an alternative to fossil resources. Wind energy resources, among the renewable energy resources, are important in terms of ensuring the reliability of energy and the use of their resources. Generators are the most important components for the conversion of wind power. Permanent magnet synchronous generators (PMSGs) are preferred in wind turbines since they have high efficiency and high volume/torque densities, thereby optimization of the PMSGs is an important topic for the wind energy community. On the one hand, these machines can cause problems due to overheating and mechanical friction during their long-time operation. To identify the performance lack of the machines due to the de-magnetization faults, systematic work has been performed. When a magnet of a PMSG is de-magnetized at different rates (i.e. 33%, 50%, and 100%), we have explored the artifacts in the electric generation. Besides, the torque performances of the generator at rated load are examined and the flux density distributions are revealed. The rated torque decreased substantially when the demagnetization rate of the magnet increased.

Zero-Voltage Ride-Through Scheme of PMSG Wind Power System Based on NLESO and GFTSMC

In this paper, a scheme for zero-voltage ride through of a permanent magnet synchronous generator wind power system is proposed. Maintaining the stability of DC-link voltage is the key to realizing zero-voltage ride through. A braking chopper is used to dissipate the active power to restrain the rise of DC-link voltage during a grid fault. However, the braking chopper-caused disturbance to the double closed-loop control of the grid side converter makes the control effect on DC-link voltage worse. Therefore, a robust current feedforward control, based on a nonlinear extended state observer and global fast terminal sliding mode control is proposed. A nonlinear extended state observer estimates the total disturbance in the system and compensates for the control law. Global fast terminal sliding mode control enables the system to reach the sliding mode surface in a finite time, and its control law is continuous without switching terms, thereby eliminating the chattering phenomenon. A nonlinear extended state observer and global fast terminal sliding mode control change the current feedforward control into a nonlinear robust current feedforward control. The control effect is improved, and the use of current transformers is reduced in practical applications, thereby reducing costs. The validity of this scheme has been verified by simulation.

A Lifetime Improvement Active Thermal Control Strategy for Wind Turbine Parallel Converters Based on Reactive Circulating Current

When the wind turbine operates under frequently fluctuating mission profiles, the power semiconductors of its converter will generate low-frequency junction temperature fluctuations, resulting in accumulation of damage to the devices and affecting the converter’s lifetime. To address the above issues, an active thermal control (ATC) strategy based on reactive circulating current for the parallel converter of permanent magnet synchronous generator wind power system was proposed in this paper, by introducing reactive circulating current during sudden wind speed drops, the thermal cycle of the power semiconductor can be effectively smoothed. On the other hand, considering the impact of the proposed strategy on the voltage vector and modulation index of the converter, both the machine-side converter (MSC) and the grid-side converter (GSC) during the control process will be analyzed in detail, then the reactive current of GSC will be limited to prevent excessive modulation index and maintain system stability without reducing the filter size. Finally, a 2 MW wind power system is utilized as a benchmark, and both short-term simulation analysis and long-term numerical results reveal the effectiveness of the control strategy proposed in this paper.

Performance analysis of modeling scale on multiband oscillations in grid-connected wind farm

Grid-connected permanent magnet synchronous generator (PMSG) wind farms may be susceptible to oscillation when connected to weak grids. This paper explores the root causes of the oscillations from two perspectives: the model and the oscillation frequency band. First, the small signal model of PMSG wind farm grid-side system is established, and the small disturbance comparison with the PMSGA full-order electromagnetic transient model in MATLAB/Simulink is carried out. Then, we calculatue the eigenvalues of the small signal model and use model analysis techniques such as participation factors calculation and root locus method to identify the critical factors that cause the oscillation modes to be dominant. Finally, time-domain simulation is used to verify the theoretical analysis. Two dominant modes are identified: the subsynchronous oscillation mode and the low-frequency oscillation mode. The subsynchronous oscillation mode is closely related to the direct current (DC) voltage control and the dynamics of DC link. The low-frequency oscillation is significantly weakened with the decrease in grid strength, and it is closely related to the phase-locked loop (PLL) control. The conclusions can provide a reference for tuning the control parameters of PMSG converter.

Sustainability of the Permanent Magnet Synchronous Generator Wind Turbine Control Strategy in On-Grid Operating Modes

Today, there are a variety of technologies for wind-generating systems, characterized by component complexity and control. Controllers are essential for the sustainability of the output voltage and the optimal speed of the generator. To overcome the problems, the system must use controllers that determine the controllers’ ability relative to each other and ultimately the controller that behaves better. This paper investigates the simulation of a PMSG wind turbine with PI, PID, neutral-point-clamped (NPC) and fuzzy controllers to study performance at different wind speeds as input. The wind energy is converted by the wind turbine and given to the PMSG generator. The PMSG output power is transferred to the power network; in this case, we have modeled the power network with a three-phase load. In order to confirm the performance of the proposed method, a PMSG wind turbine is simulated using MATLAB R2017. The simulation results show that the controllers can adjust the DC link voltage, the active power produced by the wind system.

Finite-time fault detection and reconstruction of permanent magnet synchronous generation wind turbine via sliding mode observer

In this study, a method for fault detection of a permanent magnet synchronous generator (PMSG) wind turbine is proposed. The dynamic model of the wind energy conversion system is simulated and the system’s fault is diagnosed using a proposed terminal sliding mode observer (TSMO). The nonlinear state-space equations of the closed-loop wind turbine are derived, which include a robust adaptive controller that is implemented for maximum power capture and a PI controller that is designed for pitch angle control. Then, utilising a new approach, a TSMO is designed for estimating the states and faults in a finite time. The stability and convergence of the states and fault estimation error are investigated via the Lyapunov stability theory. A PMSG wind turbine is simulated and using TSMO the states are estimated and a blade imbalance fault (BIF) fault is detected. The state and fault estimation errors converge to zero in a finite time.

Dual active disturbance rejection control of permanent magnet synchronous wind generators

Dual active disturbance rejection control of permanent magnet synchronous wind generators

Evaluation and Comparison of Different Methods for Improving Fault Ride-Through Capability in Grid-Tied Permanent Magnet Synchronous Wind Generators

Several advantages make wind-driven permanent magnet synchronous generators (PMSGs) very promising in the wind energy market, especially their fault ride-through capabilities. With the high penetration levels of today, both the grid and wind power (WP) systems are being affected by each other. Due to grid faults, the DC-bus in PMSG systems typically experiences overvoltage, which can negatively affect the generator parameters and trip the system. However, advancements in power electronics, control systems, fault limiters, FACTS, and energy storage technology make it possible to find and design satisfactory solutions and approaches. The most recent FRTC-improving techniques are mainly modified or external techniques based on controllers in PMSG-based WP. This paper evaluates the in-depth schemes of FRTC, introducing the underlying theory and traits of the different approaches to highlight the advantages and drawbacks of each. Five scenarios of DC-link voltage under zero-grid voltage are carried out by using the MATLAB SIMULINK program to assess the FRTC methods. This study shows that external device-based approaches can be efficient, but some of them are expensive, thus updated controller methods are recommended to cut costs. Research findings of this study are expected to support the deployment of FRTC technologies, as well as provide valuable input into WP research on grid integration.

Robust Speed Controller for PMSG Wind System Based on Harris Hawks Optimization via Wind Speed Estimation: A Real Case Study

Modern wind power systems have recently tended to focus on achieving fast-tracking wind speeds (WSs), high maximum power point tracking (MPPT) efficacy without mechanical sensors, and high performance under uncertain WS together with an effective control system. Therefore, a sensorless MPPT method is introduced, which calculates the actual WS to save system installation costs and boost performance levels. The implemented MPPT method is based on the approximating of the 3-order polynomial to the aerodynamics torque power coefficient. In this study, three-speed control strategies (SCSs) for a grid-connected permanent magnet synchronous wind generator (PMSWG) are examined and assessed. Harris Hawks’ algorithm (HHA)-based PI controller (HHA-PIC) is used in place of (the conventional proportional-integral controller (CPIC), and adaptive fuzzy logic controller (AFLC)) as a speed controller to overcome their drawbacks. To track the generator speed to the desired speed, the HHA-PIC is used. All the CPIC, AFLC, and HHA-PIC have been carefully thought out and constructed to satisfy the speed control loop’s responsive performance. Additionally, a comparison of SCSs amongst the categories under investigation is done. The effect of HHA on the functionality of SCS is verified using MATLAB/SIMULINK. To ensure the efficacy and supremacy of the HHA-PIC over the CPIC and AFLC, a wide variety of WSs (step change, ramp, and real fluctuations) are applied. The HHA-PIC boosts system efficiency over AFLC and CPIC by 0.81% and 8.48%, respectively. Finally, it can be said that HHA is a crucial remedy for the problems with CPIC and is superior to AFLC.

An improved damping adaptive grid‐forming control for black start of permanent magnet synchronous generator wind turbines supported with battery energy storage system

Permanent magnet synchronous generators (PMSGs) equipped with back-to-back grid-forming converters have the ability to form a 100% renewable energy power grid. Black-start is the key capability of grid-forming converters when restoring the system from a blackout. It is necessary for a grid-forming converter of the PMSG to operate in black-start and grid-connected active support modes. This paper investigates an improved damping adaptive grid-forming (DA-GFM) control method for PMSG wind turbines to suppress system frequency fluctuations and achieve a smooth black start. The proposed DA-GFM control introduces the frequency variations and natural constant function to adaptively adjust its damping coefficient in the dynamic operating progress. The implementations and effects of the proposed DA-GFM control method on the grid-forming converter are theoretically evaluated. Additionally, the detailed black-start operation process is completely studied through a microgrid system with two PMSG wind turbines and energy storages. Compared with the conventional grid-forming control, the proposed control scheme can not only suppress frequency fluctuations better, but also achieve a smooth forming power grid process. Finally, experiment tests on a controller-level hardware-in-the-loop simulation platform are carried out to validate the proposed control strategy for achieving a smooth black start.

Comparative Performance of DFIG and PMSG Wind Turbines during Transient State in Weak and Strong Grid Conditions Considering Series Dynamic Braking Resistor

The recently stipulated grid codes require wind generators to re-initiate normal power production after grid voltage sag. This paper presents a comparative performance of two commonly employed variable speed wind turbines in today’s electricity market, the doubly fed induction generator (DFIG) and the permanent magnet synchronous generator (PMSG) wind turbines. The evaluation of both wind turbines was performed for weak, normal and strong grids, considering the same machine ratings of the wind turbines. Because of the critical situations of the wind turbines during faulty conditions in the weak grids, an analysis was done considering the use of effective series dynamic braking resistor (SDBR) for both wind turbines. The grid voltage variable was employed as the signal for switching the SDBR in both wind turbines during transient state. Additionally, an overvoltage protection system was considered for both wind turbines using the DC chopper in the DC-link excitation circuitry of both wind turbines. Furthermore, a combination of the SDBR over-voltage protection scheme (OVPS) was employed in both wind turbines at weak grid condition in order to improve the performance of the variable speed wind turbines and keep the operation of the power converters within their permissible limits. Furthermore, the performance of the DFIG and PMSG wind turbines in weak grids were further investigated, considering the combination of 75% and 50% effectively sized SDBR and OVPS. It was observed that, even with a 50% reduction in SDBR or OVPS, the performance of both wind turbines is still satisfactory with faulty conditions. Therefore, it is recommended to use a combination of the SDBR and OVPS with DFIG- or PMSG-based variable speed wind turbines to achieve a superior fault ride through performance, especially in weak grids. The system performance was evaluated using the power system computer design and electromagnetic transient including DC (PSCAD/EMTDC) platform.

Fault tolerance analysis of double winding permanent magnet wind generator based on field circuit combination method

Aiming at the problem that the reliability of traditional double winding permanent magnet wind generator is low when it runs on the sea, and it cannot run normally when the fault occurs, the fault tolerance characteristics of the generator are studied. Taking a 60 kW double winding permanent magnet synchronous wind generator as an example, the finite element method is used to calculate the electromagnetic parameters of the generator under rated load, single winding fault condition and fault-tolerant condition, and the variation characteristics of magnetic density, electromagnetic torque and other electromagnetic parameters under various working conditions including fault-tolerant conditions are determined. At the same time, the thermal circuit method is used to check the hot spot temperature of the generator under various working conditions to explore the fault tolerance necessity and operation reliability of the dual winding permanent magnet wind turbine. Finally, by building a prototype platform, the rationality of the solution model and the accuracy of the calculation results are verified.

Investigating Permanent Magnet Synchronous Generator Wind Turbine Performance During Low Voltage Using Series and Bridge Type Fault Current Limiters

Investigating Permanent Magnet Synchronous Generator Wind Turbine Performance During Low Voltage Using Series and Bridge Type Fault Current Limiters