Permanent Magnet Synchronous Generator Based Wind Turbine Research Articles

MPPT 를 위한 PMSG 풍력터빈시스템에 대한 분수-차수 슬라이딩 모드 제어기 및 분수-차수 확장상태 관측기 설계

This paper designs a fractional-order sliding mode control (FSMC) of a permanent magnet synchronous generator (PMSG)-based wind energy conversion system, where attempts to extract the maximum wind power point tracking (MPPT). The combination of generator nonlinearities and parameter uncertainties may be issued to obtain the desired maximum wind power. A robust FSMC and fractional-order extended state observer are considered to address the given challenges and yield the enhanced control performance of the PMSG based wind turbine system by the MPPT technique. Simulations are carried out to examine the proposed control system for two cases with the variable step and randomly varied wind speed conditions. The simulation results verified the effectiveness and superiority of the FSMC system compared with the conventional control methods.

Coordinated Fault Ride Through Method for PMSG-Based Wind Turbine Using SFCL and Modified Control Strategy

Motivated by the issues that the cost of superconducting fault current limiter (SFCL) based fault ride through (FRT) scheme for permanent magnet synchronous generator (PMSG) is high, and it cannot tackle different voltage sags due to the constant resistance of SFCL, this paper presents a coordinated method for enhancing the FRT capability of PMSG based wind turbine (WT) under various grid faults. In the proposed method, the unbalanced power accumulated on dc-link during grid fault is dissipated by coordinating SFCL and decreasing power control (DPC) of machine side converter (MSC). Besides, a transient reactive power control (TRPC) module is implemented on the grid side converter (GSC) to meet the reactive requirement of grid codes. The coordinating mode of three modules assists the WT to tackle the severe grid faults while only the DPC is activated to deal with the mild grid faults. Several cases studies are conducted in PSCAD/EMTDC to verify the feasibility and superiority of the proposed method.

Design and Comparison of grid connected Permanent Magnet Synchronous Generator Non-salient Pole and Salient Pole Rotor Wind Turbine

Variable speed wind turbines are widely used wind energy conversion system (WECS). Among them doubly fed induction generator (DFIG) and permanent magnet synchronous generator (PMSG) are mostly used. PMSG based wind turbines are getting more popular in recent times because of their several advantages over other types. Direct drive capability and low speed operation are some of it’s significant advantage over other type. This paper describes two rotor types of grid connected PMSG, non-salient pole or round pole rotor and salient pole rotor and shows a comparative study between them. The mathematical model was designed and simulated using Matlab/Simulink. Simulation results have been shown to analyze their performances.

Intelligent Control Strategy to Enhance Power Smoothing of Renewable based Microgrid with Hybrid Energy Storage

A stand-alone renewable based microgrid (MG) performance with a hybrid energy storage system has been examined in this work. Stand-alone MG system mainly consists of a solar photovoltaic (PV) and permanent magnet synchronous generator (PMSG) based wind system. The hybrid energy storage system is based on Ni-Metal- Hydride (NiMH) battery and a supercapacitor (SC). The paper's primary goal is to propose an artificial neural network (ANN) based control strategy for charging/discharging control of Ni-Metal- Hydride battery & supercapacitor. The proposed maximum power tracking techniques (MPPT) include perturb and observe (P& O) algorithm for solar PV system while optimum torque (OT) MPPT for PMSG based wind turbine. The ANN-based control mechanism can maintain the DC bus voltage constant and trigger the supercapacitor to limit the battery current when the battery charging/ discharging current reached its threshold value. The proposed model responds quickly to intermittent nature PV-wind power generation or load power variation.

Dynamic performance analysis of grid-connected PMSG based on nonlinear control

This paper presents nonlinear control of a Wind Energy Conversion System (WECS) based Permanent Magnet Synchronous Generator (PMSG) and Five-Level Neutral Point Clamped Voltage Source Converter (5L-NPC-VSC). For WECS, the Maximum Power Point Tracking (MPPT) is a very important requirement in order to maximise the effectiveness. Therefore, the MPPT approach and grid-connected control methods are discussed. On the other hand, the proposed control techniques are based on Sliding Mode Approach (SMA) and Vector Control (VC) to achieve the MPPT, to keep the dc-link voltage constant and to the control active and reactive powers. The stability of the regulators is obtained using Lyapunov analysis. An extensive simulation study, using MATLAB/Simulink, is conducted on a 4-MW wind farm composed of two 2 MW PMSG based wind turbines.

Educational tool for analysis of proportional integral and fractional order proportional integral controlled quadratic boost converter system using MATLAB/simulink

This paper displays an simple method for identification of controller for wind based Quadratic Boost Converter Inverter system. India, being the fourth largest wind power generator has attracted numerous researchers towards the improvement of wind energy conversion system. This paper also presents improved controller techniques for a Permanent Magnet Synchronous Generator (PMSG) coupled with Cascaded Quadratic Boost Converter (QBC) and Space Vector Modulation Inverter (SVMI). The digital simulation and execution of PMSG based wind turbine along with QBC and SVM Inverter is presented in a closed loop system. The performance of closed loop system is realized using Proportional Integral (PI) and Fractional Order Proportional Integral (FOPI) controllers. Initially, the AC power from PMSG wind turbine is rectified to DC using rectifier circuit. The DC power from the bridge rectifier is then boosted to the required level using quadratic boost converter. The output from QBC is then given to the SVM inverter. The closed loop investigations are carried with PI and FOPI controllers. The simulation results of both PI and FOPI controlled QBC are compared. The outcome of FOPI controller represents that the steady state error and settling time are reduced when compared to PI controlled closed loop Quadratic Boost Converter. The overall Matlab/simulink model is applied to undergraduate/postgraduate course as a educational tool and assessed thoroughly.

Investigations on OTC-MPPT Strategy and FRT Capability for PMSG Wind System with the Support of Optimized Wind Side Controller Based on GWO Technique

Stable operation of permanent-magnet synchronous generator-based wind turbines (PMSG-WTs) is a challenging and complicated objective. Dealing with the hard situations and complex operations of the PMSG-WTs has recently become a hot issue in modern power systems. The abilities of PMSG-WT to ride over faults and operate at maximum power point (MPP) are the most critical requirements for national grid regulations. To maintain the system's reliability, PMSG-WT should remain linked to the grid during normal and abnormal conditions. Furthermore, PMSG-WT has the potential to inject reactive power during failures. It produces active and reactive power to maintain grid voltage immediately after the fault is cleared. This research uses MATLAB/Simulink to investigate the operation at MPP during wind speed changes and FRT capability during three-phase fault of PMSG-WT to validate the support of grey wolf optimizer (GWO)-based PI controllers at the wind side converter. The findings reveal that, when PMSG-WT is exposed to a fault, active and reactive power react in a complementary manner, i.e., active power to the grid drops, and injected reactive power rises to stabilize the system. While during wind speed changes the system achieves MPP operation using an optimal torque control strategy, and the output power follows the wind variations.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

System-level reliability assessment for a direct-drive PMSG based wind turbine with multiple converters

System-level reliability of wind power converter has an essential effect on the operation performance and lifespan of a wind turbine system. In this paper, a wind turbine equipped with a 2 MW direct-drive permanent-magnet synchronous generator (PMSG) serves as a case study. Considering the maximum stator current limitation of the PMSG, several multiple-converter structures and their reliability block diagrams (RBDs) are constructed for the machine side converter (MSC). To investigate the reliability influence caused by the amount of semiconductor components and the current for each component, the structures with four and five bridges in parallel are both configured. Reliability evaluation between two major parallel structures, namely, bridges in parallel and converters in parallel are also compared. In addition, the effect of different wind classes on the MSC system-level reliability has been investigated. A detailed discussion regarding the system reliability cumulative distribution function (CDF) is presented, which could serve as reference for future MSC structure design. It is concluded that the component current dominates in the system-level reliability analysis of the MSC and the standby structure can also improve the reliability under the same current level. Besides, compared with the converter structure changing, various wind classes have a minor impact on the system-level reliability.

Performance and dynamic response enhancement of PMSG based wind turbines employing boost converter-diode rectifier as the machine-side converter

Wind turbines (WTs) with Permanent magnet synchronous generator (PMSG) are mostly integrated in power systems as popular energy conversion systems. From the machine-side converter (MSC) structure point of view, there are two types of PMSG-WTs: PMSG-WT with voltage source converter (VSC) as the MSC, and PMSG-WT with boost converter-diode rectifier as the MSC. The focus in this paper is on the control modification and dynamic and transient behavior improvement of PMSG-WTs with boost converter-diode rectifier. In this way, inner control loop of the boost converter current and outer control loop of generator speed are developed and extracted. Next, the boost converter control loop is modified by adding two auxiliary control signals, known as auxiliary damping signal and auxiliary compensation signal. The auxiliary damping signal modifies the boost converter current and provides a damping torque for inhibition of WT torsional oscillations. On the other hand, the auxiliary compensation signal, as the second auxiliary signal, limits the dc-link overvoltage during the voltage dip and amends the WT low voltage ride through capability. By modifying the wind turbine control through second auxiliary signal, the size, cost and rated energy of the required dc chopper resistance decrease considerably.

MPPT Control for Grid Connected Wind Energy Conversion System Based Permanent Magnet Synchronous Generator (PMSG) and Five-Level Neutral Point Clamped Converter

This paper presents nonlinear control of a Wind Energy Conversion System (WECS) based Permanent Magnet Synchronous Generator (PMSG) and Five-Level Neutral Point Clamped Voltage Source Converter (5L-NPC-VSC). For WECS, the Maximum Power Point Tracking (MPPT) is a very important requirement in order to maximize the effectiveness. Therfore, MPPT approach and grid-connected control methods are discussed. On the other hand, the proposed control techniques are based on Sliding Mode Approach (SMA) and Vector Control (VC) to achieve the MPPT, to keep the dc link voltage constant and to the control active and reactive powers. The stability of the regulators is obtained using Lyapunov analysis. An extensive simulation study, using MATLAB/Simulink, is conducted on a 4-MW wind farm composed of two 2 MW PMSG based wind turbines.

A Novel Adaptive Control Method for Performance Enhancement of Grid-Connected Variable-Speed Wind Generators

Huge penetration of grid-tied wind generators into the existing electricity networks increased various challenges in modern power grids. Tremendous attempts are accomplished to properly enhance the behavior of the wind generation systems. This article exhibits a new self-tuned control approach for enhancing the performance of a permanent-magnet synchronous generator-based wind turbine, which is interlinked to the electricity network. The self-tuned technique relies on an improved multiband-structured subband adaptive filter (IMSAF) algorithm, which achieves less computational intricacy over the least-mean-square approach. The IMSAF algorithm-based self-tuned proportional-integral (PI) controller is employed to adjust the interface voltage source converters through a cascaded control structure. The IMSAF algorithm updates the multiple PI controllers' gains on-line without the necessity to optimize or fine-tune. To achieve realistic responses, practical wind speed data measured in Zaafarana wind farm, Egypt, are implemented in this study. The efficacy of self-tuned control approach is compared with that realized using an optimized PI control approach by the water cycle and the genetic algorithms, considering symmetrical and unsymmetrical faults, as the network disturbances. The validity of self-tuned control approach is widely confirmed by performing simulation analyses using MATLAB/Simulink software, and satisfactory responses are achieved. Notably, the IMSAF-based self-tuned control approach is realized to be an accurate means for improving the characteristic of grid-tied wind generators.

Technological Advancement in PMSG Based Wind Energy Conversion Systems: Issues and Challenges

Background: Since its beginning in 1980, wind energy generation has gained newer heights and emerged as the most promising renewable energy technology at present. Wind turbine rating has increased from few kW to MW and now multi-MW turbines are also available and in operation too. Introduction: Impact of wind turbines on the grid has significantly increased with increased penetration of wind power into the grid. In order to improve the performance characteristics of the wind turbines, and make them suitable for grid integration, more advanced generators, control schemes, and power converters are required. Latest wind energy market trends and research articles reflect the popularity and market capture of Permanent Magnet Synchronous Generator (PMSG) for wind turbine applications. Method: The present work is dedicated to important electrical aspects concerning PMSG based wind energy conversion system. Starting with the technological development of wind turbine, state-of-the-art PMS based wind turbine concepts with power electronic converter topologies are discussed. Result: A comprehensive analysis of converter topology, grid integration, integration issues, and future research and technology trends are presented.In addition steady state performance analysis of PMSG based wind turbine is presented depicting issues with different control schemes. Conclusion: The study presented in this paper envisages help to the researcher in this area by providing them clear insight of various power electronic interfaces, their control complexities and various issues of concern. In addition we are assure that steady state analysis presented in this paper will attract the newcomers in this field of research.

Adaptive Pitch Control of Variable-Pitch PMSG Based Wind Turbine

This paper presents an adaptive pitch-angle control approach for a permanent magnet-synchronous generator-based wind turbine (PMSG-WT) connecting with a power grid to limit extracted power above the rated wind speed. In the proposed control approach, a designed perturbation observer is employed for estimating and compensating unknown parameter uncertainties, system nonlinearities, and unknown disturbances. The proposed control approach does not require full state measurements or the accurate system model. Simulation tests verify the effectiveness of the proposed control approach. The simulation results demonstrate that compared with the feedback linearizing controller, conventional vector controller with proportional-integral (PI) loops, and PI controller with gain scheduling, the proposed control approach can always maintain the extracted wind power around rated power, and has higher performance and robustness against disturbance and parameter uncertainties.

Design of robust MPPT controller for grid-connected PMSG-Based wind turbine via perturbation observation based nonlinear adaptive control

This paper presents a robust maximum power point tracking (MPPT) control scheme for a grid-connected permanent magnet synchronous generator based wind turbine (PMSG-WT) using perturbation observation based nonlinear adaptive control. In the proposed control scheme, system nonlinearities, parameter uncertainties, and external disturbances of the PMSG-WT are represented as a lumped perturbation term, which is estimated by a high-gain perturbation observer. The estimate of the lumped perturbation is employed to compensate the actual perturbation and further achieve adaptive feedback linearizing control of the original nonlinear system, without requiring the detailed system model and full state measurements. The effectiveness of the proposed control scheme is verified through both simulation studies and experimental tests. The results show that, compared with the conventional vector controller and the standard feedback linearizing controller, the proposed control strategy provides higher power conversion efficiency and has better dynamic performances and robustness against parameter uncertainties and external disturbances.

Modeling, control and stability analysis of grid connected PMSG based wind turbine assisted with diode rectifier and boost converter

Permanent magnet synchronous generator (PMSG) based wind turbines (WTs) are widely used as grid connected energy sources. Usually, a PMSG based wind energy system is connected to the grid via machine side and grid side converters. From the machine side converter point of view, there are two types of PMSG-based WTs: PMSG with back-to-back voltage source converters, and PMSG assisted with diode rectifier and boost converter. Since most of the research works regarding the PMSG-based WTs are devoted to the former type, this paper deals with the elaborated controller design and stability analysis of the grid connected PMSG based WT assisted with diode bridge rectifier and boost converter. Hence, the linearized average dynamic model of the combined system comprising PMSG, diode rectifier and boost converter is presented. Based on the linearized model, the relation between the PMSG electromagnetic torque and boost converter current is extracted, and then system’s control-loops are developed. Next, small signal stability of the full system comprising PMSG, boost-diode rectifier, dc-link capacitor, GSC, and corresponding controllers is presented and then impact of PMSG speed controller on the stability of the system is examined theoretically and by time domain simulations.

Steady-state assessments of PMSGs in wind generating units

The number of fully-rated converter wind turbine generators equipped with a Permanent Magnet Synchronous Generator (PMSG) has sensibly increased in the late years. The optimal utilization and controllability of a PMSG is achieved using a Pulse Width Modulation – Voltage Source Converter (PWM-VSC) that allows interfacing the electric machine with the distribution network by means of a DC link. The generator/Machine-Side Converter (MSC) controls the operation of the PMSG. This paper proposes a methodology to assess the feasibility of the steady-state working points of PMSG based wind turbines without running a set of time-consuming time-domain simulations. Three control objectives for MSC are usually considered: stator voltage control, unitary power factor control and torque control. The aim of the present paper is that of providing an analytical methodology to check the feasibility of the steady-state working points dictated by different control strategies of the MSC starting from the specific operational constraints provided by the wind power plants characteristics. The effectiveness of the proposed methodology is demonstrated comparing numerical results of a MATLAB® implementation against dedicated time-domain simulations. Simulations results demonstrated the appropriate performance of the proposed methodology characterized by the almost negligible computational time required.

Dynamic state estimation of a permanent magnet synchronous generator‐based wind turbine

Precise modelling, control and monitoring of machines improve the overall stability and operation of power systems. State estimation reduces the effect of noises and presents all hidden variables, which can be beneficial especially in non-linear control. In this study, first, a complete 16th-order state space model is developed for a grid-connected permanent magnet synchronous generator-based wind turbine (PMSG-WT). Due to non-linearity of the model, extended Kalman filtering is utilised for state estimation. A phasor measurement unit connected to permanent magnet synchronous generator bus is utilised to provide required electrical values for state estimation in a synchronous manner. In order to evaluate the accuracy of the proposed algorithm, four different cases are studied corroborating the robustness of the proposed algorithm in the presence of high noises or in the case of large disturbances. Some comparisons are also provided with another non-linear model proposed recently for PMSG-WT, which verifies the advantages of the proposed model. Such results are expected to improve stability of wind farms especially in the case of large disturbances, which can lead to enhancing the whole network stability.

Design and Performance Comparison of PI and Adaptive Current Controllers for a WECS

This work proposes a novel controller in a stationary reference frame for permanent magnet synchronous generator (PMSGs) of grid-connected wind turbines. The wind energy conversion systems (WECS) adopt a Back-To-Back converter system with voltage source inverter (VSI) and a phase-locked loop to track continuously the fundamental frequency and its phase from voltage node that is connected to the system generation. One of the central themes of this paper is the development of a control scheme that uses a B-spline artificial neural network for controllers tuning when the system is subjected to disturbances. The B-spline neural network must be able to enhance the system performance and the online parameters updated can be possible. This work proposes the use of adaptive PI controllers to regulate the current, frequency and DC-link voltage. Results of the dynamic behavior of the whole WECS are presented along with different cases subject to various disturbances. The simulations show the feasibility and robustness of the proposed control schemes for PMSG based wind turbines.

A Downsizing Strategy for Combinatorial PMSG Based Wind Turbine and Micro-SMES System Applied in Standalone DC Microgrid

This paper presents a combinatorial standalone permanent magnet synchronous generator (PMSG) based variable speed wind turbine (VSWT) and small-size superconducting magnetic energy storage (SMES) system into the DC microgrid system. The principal purpose of SMES system is to preserve power balance by absorbing power during peak wind generation and to release it during low power generation. This work accomplished by describing the optimized design of the SMES solenoid coil, ensuring the desired energy storage capacity based on the simulated annealing (SA) algorithm. More importantly, the new control technique is developed for bi-directional DC-DC converter to level output power of the wind turbine depending on the demand thereby reducing the capacity of the DC-DC converter system. Detailed simulation studies implemented in PSCAD/EMTDC corroborate the superior robustness and balancing performance of the proposed micro-SMES controller with an optimal coil size under various situations including variable wind speed. This combination will result in “scaling-factors” knowledge through downsizing strategy which will lead to the most efficient system from cost cutting, energy savings, and downsizing viewpoints.