Permanent Magnet Synchronous Generator Wind Research Articles

A New Fault Diagnosis Algorithm for PMSG Wind Turbine Power Converters under Variable Wind Speed Conditions

Although Permanent Magnet Synchronous Generator (PMSG) wind turbines (WTs) mitigate gearbox impacts, they requires high reliability of generators and converters. Statistical analysis shows that the failure rate of direct-drive PMSG wind turbines’ generators and inverters are high. Intelligent fault diagnosis algorithms to detect inverters faults is a premise for the condition monitoring system aimed at improving wind turbines’ reliability and availability. The influences of random wind speed and diversified control strategies lead to challenges for developing intelligent fault diagnosis algorithms for converters. This paper studies open-circuit fault features of wind turbine converters in variable wind speed situations through systematic simulation and experiment. A new fault diagnosis algorithm named Wind Speed Based Normalized Current Trajectory is proposed and used to accurately detect and locate faulted IGBT in the circuit arms. It is compared to direct current monitoring and current vector trajectory pattern approaches. The results show that the proposed method has advantages in the accuracy of fault diagnosis and has superior anti-noise capability in variable wind speed situations. The impact of the control strategy is also identified. Experimental results demonstrate its applicability on practical WT condition monitoring system which is used to improve wind turbine reliability and reduce their maintenance cost.

Effective supervisory controllers designed for optimal energy management in permanent magnet synchronous generator wind turbine with battery storage

Optimal control of large-scale wind turbine has become a critical issue for the development of renewable energy systems and their integration into the power grid to provide reliable, secure, and efficient electricity. In this article, a new supervisory control system for the optimal management and robust operation of a wind turbine generator and a battery energy storage system is presented. The proposed coordinated controller can mitigate both active and reactive power disturbances due to the intermittency of wind speed and load change. Moreover, the control strategy ensures the maximum power extraction capability of direct-drive wind turbine. This supervisory controller is made up of three subsystems. The first one is used to track the maximum power point for variable wind speeds; the control algorithm employs a fuzzy logic controller and a second-order sliding mode controller to effectively meet this target. The task of the second one is to maintain the required DC-link voltage level. This is achieved by controlling the bidirectional power flow in the storage batteries using DC–DC converter. Whereas in the last, a second-order sliding mode controller is investigated to achieve smooth regulation of grid active and reactive power quantities, which provides better results in terms of attenuation of the harmonics present in the grid courant compared with the conventional first-order sliding mode controller. Extensive simulation studies under different conditions of wind speed are carried out in MATLAB/Simulink, and the results confirm the effectiveness of the new supervisory control system.

Zero-Sequence Current Suppression Strategy for Open Winding PMSG Fed by Semicontrolled Converter

The open winding permanent magnet synchronous generator (PMSG) fed by semicontrolled converter takes the advantages of lower expense, simplified driving circuit, and reliable control realization. With a single dc supply, the implementation of open winding configuration in practical application could be much convenient. However, the common dc bus supplied configuration provides a zero-sequence current circuit unavoidably. In order to reduce the harmonic distortion, a zero-sequence current suppression scheme is proposed. The space vector pulse width modulation (SVPWM) technique is adopted to modulate the desired voltage reference in the three-dimensional (3-D) coordinate system by distributing duty cycles for active and zero vectors. With a comprehensive investigation on the semicontrolled configuration, the achievable modulation region for αβ 0 voltage vector reference is analyzed. Finally, the zero-sequence current suppression method with 3-D-SVPWM technique is implemented in a 1 kW open winding PMSG experimental system.

Hybrid Intelligent Control Method to Improve the Frequency Support Capability of Wind Energy Conversion Systems

This paper presents a hybrid intelligent control method that enables frequency support control for permanent magnet synchronous generators (PMSGs) wind turbines. The proposed method for a wind energy conversion system (WECS) is designed to have PMSG modeling and full-scale back-to-back insulated-gate bipolar transistor (IGBT) converters comprising the machine and grid side. The controller of the machine side converter (MSC) and the grid side converter (GSC) are designed to achieve maximum power point tracking (MPPT) based on an improved hill climb searching (IHCS) control algorithm and de-loaded (DL) operation to obtain a power margin. Along with this comprehensive control of maximum power tracking mode based on the IHCS, a method for kinetic energy (KE) discharge control of the supporting primary frequency control scheme with DL operation is developed to regulate the short-term frequency response and maintain reliable operation of the power system. The effectiveness of the hybrid intelligent control method is verified by a numerical simulation in PSCAD/EMTDC. Simulation results show that the proposed approach can improve the frequency regulation capability in the power system.

Effective MPPT technique and robust power control of the PMSG wind turbine

Wind generator performance improvement requires sophisticated and robust control techniques to overcome various constraints and achieve optimal aerodynamic energy conversion. Because of the continuously changing nature of the wind, the output power of a wind energy conversion system (WECS) can be maximized if the wind rotor is driven at an optimal rotational speed for a particular wind speed. This is achieved with a maximum power point tracking (MPPT) controller. Over the years, a variety of MPPT studies have been made, but very few provide guidelines to single out the most suited MPPT technique. In this paper, a comprehensive comparison of the four most used schemes has been made in relation to a permanent magnet synchronous generator (PMSG) wind turbine system. These techniques can be classified into various categories. The obtained results show clearly the superiority of the fuzzy logic control (FLC) technique. Using this MPPT approach, the generated power by the turbine is considered to be, in terms of power control, an auxiliary source feeding a grid. To achieve smooth regulation of the active and reactive power exchange between the PMSG and the grid, direct power control, using space vector modulation DPC‐SVM strategy combined with sliding mode control (SMC) is applied in the grid‐side converter. Simulation results show the efficiency and reliability of the control strategy proposed in this paper. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Improved multi-objective model predictive control of permanent magnetic synchronous generator wind power system

A novel sorting-based multi-objective model predictive control strategy for controlling converters of permanent magnetic synchronous generator wind turbines is proposed in this paper. To avoid the nontrivial process of scale factors tuning which is typical in traditional multi-objective model predictive control, sorting and ranking is incorporated in this method where quicksort is utilized to sort the multiple control variables with the principle of variable that has smaller objective function value ranking higher. In addition, predictive direct torque control and direct power control are adopted separately for the generator-side and the grid-side converters in which one-step delay in digital implementation and switching losses are compensated without deterioration of system stability. In order to verify the effectiveness of the proposed method, simulations and experimental tests are conducted separately with results showing that the proposed method can get excellent steady and dynamic performance with lowered fluctuations and switching frequencies while avoiding the tedious scale factors tuning process.

Optimum design of proportional-integral controllers in grid-integrated PMSG-based wind energy conversion system

Summary In this paper, a direct-driven small permanent magnet synchronous generator (PMSG) wind energy conversion system (WECS) with a back-to-back power converter working in grid-connected mode is discussed. Control structures based on field-oriented control and voltage-oriented control mechanisms are proposed for machine-side converter and grid-side converter, respectively. Optimization approaches namely ‘modulus optimum’ and ‘symmetric optimum’ are used to obtain analytical expressions for the selection of the parameters of involved proportional-integral (PI) controllers in different control loops. A transient system simulation using SimPowerSystem is built to evaluate the performance of the PMSG-based WECS by employing selected values of PI controller parameters both under varying wind conditions and under symmetrical and asymmetrical grid-fault conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Optimal Power Control Strategy of Maximizing Wind Energy Tracking and Different Operating Conditions for Permanent Magnet Synchronous Generator Wind Farm

This paper develops the model and the control of a Wind Farm System (WFS) based on Permanent Magnet Synchronous Generator (PMSG) and interconnected to the electric network. It evaluates the performance of the system for fault conditions as well as for normal working conditions. The proposed control law combines Vector Control (VC) and Maximum Power Point Tracking (MPPT) control methodology in order to maximize the generated power from Wind Turbine Generators (WTG). So, WFS can not only capture the maximum wind energy, but also can maintain the frequency and amplitude of the output voltage. Simulation results have shown the effectiveness of the proposed control method for variable speed WFS based on the PMSG.

Advanced Control Strategy of Back-to-Back PWM Converters in PMSG Wind Power System

This paper proposes a control scheme of back-to-back PWM converters for the permanent magnet synchronous generator (PMSG) wind turbine system. The DC-link voltage can be controlled at the machine-side converter (MSC), while the grid-side converter (GSC) controls the grid active power for a maximum power point tracking (MPPT). At the grid fault condition, the DC-link voltage controller is designed using a feedback linearization (FL) theory. For the MPPT, a proportional control loop is added to the torque control to reduce the influence of the inertia moment in the wind turbines, which can improve its dynamic performance. The validity of this control algorithm has been verified by the simulation of the 2-MW PMSG wind turbine system.

A Permanent Magnet Synchronous Generator Model and Its Control Strategy

永磁同步电机(PMSG)控制是发电机组中最为关键的环节，其直接关系着发电机输出的电能质量。本文通过分析永磁同步风力发电机数学机理，分别对发电机的电压、磁链、电磁转矩以公式进行推导，根据坐标变换原理，提出采用基于外环速度、内环电流控制的双闭环矢量控制策略，该方法简便易行，对输出变量控制效果较好，最后建立发电机侧仿真模型，并分析仿真结果，验证控制策略的正确性和有效性。 Permanent magnet synchronous motor (PMSG) control is the key link in the generator set, and it di-rectly relates to the power quality of the generator output. In this paper, through analysis of perma-nent magnet synchronous wind generator mathematical mechanism, generator voltage, flux and elec- tromagnetic torque are derived respectively using formulas. According to the principle of coordinate transformation, double closed loop vector control strategy based on outer ring speed and current loop control is proposed. The method is simple and convenient, and on the output variable it has a good control effect. And finally this paper establishes the simulation model of the generator side, analyzes the simulation results and verifies the correctness and effectiveness of the control strategy.

Maximum Power Point Tracking Control Based on a Nonlinear Backstepping Approach for a Permanent Magnet Synchronous Generator Wind Energy Conversion System Connected to a Utility Grid

AbstractWith the high penetration of wind energy resources in the electric grid, the effectiveness of variable‐speed wind energy conversion systems (WECS) can be enhanced considerably by a careful choice of the control strategy. This paper presents a control strategy to track the maximum power point for a wind power generation system. This system is based on a permanent magnet synchronous generator (PMSG) wind turbine system with full‐power back‐to‐back converters and connected to a utility grid. The system organization and control approach are presented. The controller is based on the nonlinear backstepping approach, which is robust to parameter uncertainties. The generator‐side converter is employed to regulate the velocity of the PMSG with maximum power point tracking, and the grid‐side converter is used to control the dc‐link voltage and to regulate the power factor with a varying wind velocity. The proposed nonlinear backstepping approach is used to control both the PMSG and grid‐side converters of a WECS. By using Lyapunov analysis, the stability of the regulators is assured. The proposed structure and control methodology are verified through Matlab simulations. Furthermore, a comparison of simulation results based on the proposed backstepping algorithm and conventional proportional integral controller is provided.

Stand Alone Performance of Permanent Magnet Synchronous Wind Power Generator with Current Source Matrix Converter

—A matrix converter is a voltage/current source AC/AC frequency converter. In grid-connected operation of a variable-speed permanent magnet synchronous wind power generator, the matrix converter is normally controlled as a voltage source converter. In this control method, the generator-side voltage is synthesized from the grid-side voltage source. However, in the stand-alone mode of operation, the grid-side stiff voltage source is not available, and the input filter of the matrix converter is unstable. In this article, a new control method is presented that controls a permanent magnet synchronous wind generator in a stand-alone mode with a matrix converter as a current source converter. The proposed method is so fast that it can control the matrix converter small capacitor voltage despite the generator large inductance and without any input filter instability. A multi-pole permanent magnet synchronous wind generator is simulated to prove the performance of the proposed control strategy.

Enhanced Control for a Direct-driven Permanent Synchronous Generator Wind-power Generation System with Flywheel Energy Storage Unit Under Unbalanced Grid Fault

—This article presents an enhanced control strategy for a direct-driven permanent synchronous generator based wind-power generation system with a flywheel energy storage unit. The behaviors of the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit under unbalanced grid fault conditions are investigated. Three control targets for the grid-side converter during network unbalance conditions are identified, including eliminating the oscillations in the total active power or reactive power or no negative-sequence current injecting into the grid. Meanwhile, the DC-link voltage oscillations can be effectively suppressed during the unbalanced grid fault by controlling the flywheel energy storage unit. Furthermore, a proportional–integral-resonant controller is designed for the flywheel motor to eliminate the oscillations in the DC-link voltage. Finally, the proposed coordinated control strategy for the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit has been validated by the simulation results of a 1-MW direct-driven permanent magnet synchronous generator wind power generation system with a flywheel energy storage unit under unbalanced grid fault.

Power Control of Directly Driven Wind Generation System Based on Superconducting Magnetic Energy Storage

The increasing wind power penetration poses significant technical problems to the development of electric power systems. In this article, an integrated control strategy is proposed based on the characteristics of the directly driven permanent magnet synchronous generator wind turbine. The directly driven permanent magnet synchronous generator wind turbine is incorporated with superconducting magnetic energy storage, which can smooth the wind power fluctuations, enhance the low-voltage ride-through capability of the wind generation system, and achieve an uninterruptible power supply to local loads under isolated grid operation. According to the MATLAB/SIMULINK-based (The MathWorks, Natick, Massachusetts, USA) digital computer simulation model, the proposed control strategy is confirmed to be effective in power control of grid operation.

Design of High Performance Permanent-Magnet Synchronous Wind Generators

This paper is devoted to the analysis and design of high performance permanent-magnet synchronous wind generators (PSWGs). A systematic and sequential methodology for the design of PMSGs is proposed with a high performance wind generator as a design model. Aiming at high induced voltage, low harmonic distortion as well as high generator efficiency, optimal generator parameters such as pole-arc to pole-pitch ratio and stator-slot-shoes dimension, etc. are determined with the proposed technique using Maxwell 2-D, Matlab software and the Taguchi method. The proposed double three-phase and six-phase winding configurations, which consist of six windings in the stator, can provide evenly distributed current for versatile applications regarding the voltage and current demands for practical consideration. Specifically, windings are connected in series to increase the output voltage at low wind speed, and in parallel during high wind speed to generate electricity even when either one winding fails, thereby enhancing the reliability as well. A PMSG is designed and implemented based on the proposed method. When the simulation is performed with a 6 Ω load, the output power for the double three-phase winding and six-phase winding are correspondingly 10.64 and 11.13 kW. In addition, 24 Ω load experiments show that the efficiencies of double three-phase winding and six-phase winding are 96.56% and 98.54%, respectively, verifying the proposed high performance operation.

Incipient Stator Insulation Fault Detection of Permanent Magnet Synchronous Wind Generators Based on Hilbert–Huang Transformation

Incipient stator winding fault in permanent magnet synchronous wind generators (PMSWGs) is very difficult to be detected as the fault generated variations in terminal electrical parameters are very weak and chaotic. This paper simulates the incipient stator winding faults at different degree of insulation degradation of one turn in the winding of a PMSWG. Cosimulation method by combining finite element model and external circuits is used. Hilbert-Huang transformation is applied to detect the very early stage fault in interturn insulation by analyzing the stator current. Detection results show that the minimum detectable severity degree of interturn fault in this paper is 0.1488%, which is much better than the best record in the literature.

Influence of Wind Farm with PMSG Type on Small Signal Stability of Power System

In order to study the small signal stability of power grid after grid-connection of large-scale Permanent Magnet Synchronous Generator (PMSG) wind farms, the mathematical model of PMSG was established. By means of simulation on a simple power system, the damping characteristics of grid under different wind power penetration and different access location of wind farms were studied in detail. Simulation results show that along with the increase of wind power, the inter-area oscillation mode damping would reduce. When wind farm was attached the receiving area, the inter-area oscillation mode damping was lower than it when wind farm was attached the supplying area.

Adaptive Controller for Drive System PMSG in Wind Turbine

This paper proposes adaptive Maximum Power Point Tracking (MPPT) controller for Permanent Magnet Synchronous Generator (PMSG) wind turbine and direct power control for grid side inverter for transformer less integration of wind energy. PMSG wind turbine with two back to back voltage source converters are considered more efficient, used to make real and reactive power control. The optimal control strategy has introduced for integrated control of PMSG Maximum Power Extraction, DC link voltage control and grid voltage support controls. Simulation model using MATLAB Simulink has developed to investigate the performance of proposed control techniques for PMSG wind turbine steady and variable wind conditions. This paper shows that the direct driven grid connected PMSG system has excellent performances and confirms the feasibility of the proposed techniques. While the wind turbine market continues to be dominated by conventional gear-driven wind turbine systems, the direct drive is attracting attention. PM machines are more attractive and superior with higher efficiency and energy yield, higher reliability, and power-to-weight ratio compared with electricity-excited machines.

Novel Topology and Control Strategy of HVDC Grid Connection for Open Winding PMSG based Wind Power Generation System

To satisfy the high voltage direct current (HVDC) grid connection demand for wind power generation system, a novel topology and control strategy of HVDC grid connection for open-winding permanent magnet synchronous generator (PMSG) based wind power generation system is proposed, in which two generator-side converter and two isolated DC/DC converters are used to transmit the wind energy captured by open winding PMSG to HVDC grid. By deducing the mathematic model of open winding PMSG, the vector control technique, position sensorless operation, and space vector modulation strategy is applied to implement the stable generation operation of PMSG. Finally, the simulation model based on MATLAB is built to validate the availability of the proposed control strategy.

A new hybrid control method for controlling back-to-back converter in permanent magnet synchronous generator wind turbines

The increasing environmental concerns during the 20th century have moved the research focus from conventional electricity sources to the renewable ones. In renewable power generation, wind energy has been noted as the most rapidly growing technology; it attracts interest as one of the most cost-effective ways to generate electricity from renewable resources. Moreover, using of power electronic devices to regulate and control of the generated power and transfuse to the grid is essential. In wind power systems, by using different control methods on the power electronic converter, synchronization of these resources to power grid is obtained. Studded wind turbine consists of a permanent magnet synchronous generator which is connected to the grid by a back to back (B2B) converter. In this paper, the main purposes are maximum point power tracking of wind turbine and transfusion to grid, control of reactive power by B2B converter and also fixing DC-link voltage in DC-link reference voltage. Proposed control method consists of vector control, combined tilt-integral-derivative compensator, and fuzzy controller. In order to verify the proposed method, a 1.5 MW wind turbine system is simulated in MATLAB/SIMULINK.