Performance analysis of 20 Pole 1.5 KW Three Phase Permanent Magnet Synchronous Generator for low Speed Vertical Axis Wind Turbine

This paper gives performance analysis of a three phase Permanent Magnet Synchronous Generator (PMSG) connected to a Vertical Axis Wind Turbine (VAWT). Low speed wind condition (less than 5 m/s) is taken in consideration and the entire simulation is carried in Matlab/Simulink environment. The rated power for the generator is fixed at 1.5 KW and number of pole at 20. It is observed under low wind speed of6 m/s, a turbine having approximately1 mof radius and2.6 mof height develops 150 Nm mechanical torque that can generate power up to 1.5 KW. The generator is designed using modeling tool and is fabricated. The fabricated generator is tested in the laboratory with the simulation result for the error analysis. The range of error is about 5%-27% for the same output power value. The limitations and possible causes for error are presented and discussed.

Comparative Performance of Fixed-Speed and Variable-Speed Wind Turbine Generator Systems

In the early development of the wind energy, the majority of the wind turbines have been operated at constant speed. Subsequently, the number of variable-speed wind turbines installed in wind farms has increased. In this paper, a comparative performance of fixed and variable speed wind generators with Pitch angle control has been presented. The first is based on a squirrel cage Induction Generator （IG） of 315 kW rated power, connected directly to the grid. The second incorporated a Permanent Magnet Synchronous Generator （PMSG） of 750 kW rated power. The performances of each studied wind generator are evaluated by simulation works and variable speed operation is highlighted as preferred mode of operation.

Transient Stability Analysis of Synchronous Generator in Power System with Renewable Power Sources Installed

The impact of large-scale grid-connected renewable power sources, such as wind generators and solar photovoitaic systems, on transient stability of synchronous generators is discussed in this paper. The permanent magnet synchronous generator with variable speed wind turbine is used in the simulation analysis as a wind generator model. The transient stability analysis is performed for IEEE 9-bus system model with high-penetration renewable power sources. The effect of FRT （fault ride-through） capability implemented for each power source on the transient stability is investigated.

Electromagnetic and Mechanical Stress Analysis of Wind-Driven Synchronous Reluctance Generator

The investigation explores the mechanical stress and electromagnetic performance for a wind-driven synchronous reluctance generator(SRG).The change in the mechanical stress due to the presence of centripetal force,wind speed,and rotor speed are evaluated for different thickness of tangential and radial ribs.Moreover,the variation in the electromagnetic feature such as the q−and d−axes flux,reactance ratio,inductance,torque and torque ripple are discussed for different thickness of tangential and radial ribs.Increasing both tangential and radial ribs thickness has an effect on the electromagnetic performance,but it is observed that effect is significantly more with the variation of tangential rib thickness.Similarly,the mechanical stress analysis for rotor design has been explored in this paper.It is observed that high concentration of peak stress on the rotor ribs,which limits the range of rotor speed.

Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

PID-Type Fuzzy Controller for Grid-Supporting Inverter of Battery in Embedded Small Variable Speed Wind Turbine

Frequency and voltage of embedded variable speed wind turbine (VSWT) driving a permanent magnet synchronous generator (PMSG) is strongly affected by wind speed fluctuations. In practice, power imbalance between supply and demand is also common, especially when VSWT-PMSG is connected to a weak micro grid (MG). If load demand fluctuations become high, isolated MG may be unable to stabilize the frequency and voltage so that battery storage needs to be installed into the MG to adjust energy supply and demand. To allow flexible control of active and reactive power flow from/to battery storage, grid-supporting inverters are used. For a system that contains highly nonlinear components, the use of conventional linear proportional-integral-derivative (PID) controllers may cause system performance deterioration. Additionally, these controllers show slow, oscillating responses, and complex equations are required to obtain optimum responses in other controllers. To cope with these limitations, this paper proposes PID-type fuzzy controller (PIDfc) design to control grid-supporting inverter of battery. To ensure safe battery operating limits, we also propose a new controller scheme called intelligent battery protection (IBP). This IBP is integrated into PIDfc. Several simulation tests are performed to verify the scheme’s effectiveness. The results show that the proposed PIDfc controller exhibits improved performance and acceptable responses, and can be used instead of conventional controllers.

Enhancement of DC-Link Protection of PMSG Based Wind Turbine under Network Disturbance by Using New Buck Controller System

Protection system for DC-link circuit of back-to-back converter of PMSG （Permanent Magnet Synchronous Generator） based wind turbine is essential part for the system to ride through a network fault in grid system. Voltage on the DC-link circuit can be increased significantly due to power unbalance between stator side converter and grid side converter. Increase of DC-link circuit voltage can lead to a damage of IGBT of the converter and control system failure. In this paper performance enhancement of DC-link protection of PMSG based Wind turbine by using new control system of buck converter is proposed. The buck converter is used to control supplied voltage of a breaking resistor to dissipate energy from the wind generator during network disturbance. In order to investigate effectiveness of the proposed DC-link protection system, fault analysis is performed in the simulation study by using PSCAD/EMTDC software program. In addition, comparative analysis between the proposed protection system and the conventional protection system using DC chopper is also performed.

Adaptive VSG control of flywheel energy storage array for frequency support in microgrids

The application of virtual synchronous generator(VSG)control in flywheel energy storage systems(FESS)is an effective solution for addressing the challenges related to reduced inertia and inadequate power supply in microgrids.Considering the significant variations among individual units within a flywheel array and the poor frequency regulation performance under conventional control approaches,this paper proposes an adaptive VSG control strategy for a flywheel energy storage array(FESA).First,by leveraging the FESA model,a variable acceleration factor is integrated into the speed-balance control strategy to effectively achieve better state of charge(SOC)equalization across units.Furthermore,energy control with a dead zone is introduced to prevent SOC of the FESA from exceeding the limit.The dead zone parameter is designed based on the SOC warning intervals of the flywheel array to mitigate its impact on regular operation.In addition,VSG technology is applied for the grid-connected control of the FESA,and the damping characteristic of the VSG is decoupled from the primary frequency regulation through power differential feedback.This ensures optimal dynamic performance while reducing the need for frequent involvement in frequency regulation.Subsequently,a parameter design method is developed through a small-signal stability analysis.Consequently,considering the SOC of the FESA,an adaptive control strategy for the inertia damping and the P/ωdroop coefficient of the VSG control is proposed to optimize the grid support services of the FESA.Finally,the effectiveness of the proposed control methods is demonstrated through electromagnetic transient simulations using MATLAB/Simulink.

Control of Virtual Synchronous Generator for Frequency Regulation Using a Coordinated Self-adaptive Method

Power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation systems.However,it cannot take into account the dynamic regulation characteristics of frequency.Thus,when the system encounters a sudden change in load or disturbance,the dynamic process of frequency regulation will be greatly influenced.In view of this issue,an improved VSG control strategy based on a coordinated self-adaptive(CSA)method is proposed.The time domain analysis method is used to study the influences of virtual inertia and damping parameter perturbation on the system steady and dynamic performances.Furthermore,in order to make the control strategy suitable for large load changes and suppress frequency variations beyond the limit,the secondary frequency modulation is introduced into the control loop.Through the coordinated adaptive control of virtual inertia,virtual damping and frequency modulation,the dynamic performance of vSG frequency regulation can be obviously improved.Simulation and experiment results have verified the effectiveness of the proposed CSA control strategy.

Small-signal Angular Stability of Power System as Affected by Grid-connected Variable Speed Wind Generators—A Survey of Recent Representative Works

This paper reviews the status and progress of the investigation on power system small-signal angular stability as affected by grid-connected variable speed wind generators(VSWGs).The review is carried out on the basis of a survey of recently published representative papers.Strategies of the investigation made in those selected papers are classified into two groups:1)VSWGs displacing synchronous generators(SGs);2)VSWGs simply being added in a power system.The diversification of the results of the investigation is highlighted in the survey.Careful analysis on two strategies of the investigation is conducted in this paper.It is revealed that in the strategy of VSWGs displacing SGs,there are two factors which could affect power system small-signal angular stability differently:1)Withdrawing the SGs’dynamics;2)adding the VSWGs’dynamics.In the strategy of adding VSWGs in the power system,there are also two affecting factors:1)Change of load flow brought about by the VSWGs;2)dynamic interactions with the SGs introduced by the VSWGs.Hence diversified results of the investigation obtained so far are not only due to the dependence of the investigation on sample power systems used,but also caused by the mixture of different affecting factors.This paper is concluded with a summary of key issues of the investigation for future work.

Wide Speed Range Permanent Magnet Synchronous Generator Design for a DC Power System

A wide speed range permanent magnet synchronous generator(PMSG)system is studied in this paper,including the PMSG design and comparative study on control strategies with a pulse width modulation(PWM)rectifier,the purpose of which is to regulate the DC-link voltage.It is of great importance to study the foregoing DC power system based on the PMSG and PWM rectifier,where vector control(VC)can be implemented and the corresponding field-weakening strategy can be realized by injecting a field-weakening current component without any auxiliary devices.Large machine inductance is desired in order to limit the short-circuit current and the loaded voltage drop.Different control strategies including VC,direct torque control(DTC)and direct voltage control(DVC)are studied and compared with both simulations and experiments.

Control Strategy of Wind Turbine Based on Permanent Magnet Synchronous Generator and Energy Storage for Stand-Alone Systems

This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system.An energy storage system(ESS)including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power converter through the power electronics interface.Wind is the primary power source of the system,the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system,respectively.In this paper,a control strategy is proposed for the operation of this variable speed wind turbine in a stand-alone system,where the generator-side converter and the ESS operate together to meet the demand of the loads.This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full-scale power converter in a small range.A simulation model of a variable speed wind turbine in a stand-alone system is developed using the simulation tool of PSCAD/EMTDC.The dynamic performance of the stand-alone wind turbine system and the proposed control strategy is assessed and emphasized with the simulation results.

PMSG Wind Energy Conversion System: Modeling and Control

In this paper, a model of a variable speed wind turbine using a permanent magnet synchronous generator (PMSG) is presented and the control schemes are proposed. The model presents the aerodynamic part of the wind turbine, the mechanic and the electric parts. Simulations have been conducted with Matlab/Simulink to validate the model and the proposed control schemes.

High Efficiency Double–Fed Induction Generator Applied to Wind Power Generator Technical Analyses

High efficiency Double-Fed Induction Generator applies new power electronic technology, and utilizes vector control to fix the magnetic direction of the stator to the vertical axis. Adjusting the input current of rotor via an inverter can separately control the cross axis and vertical axis current of real power and reactive power of a generator. Traditionally, rotating speed affects frequency and the output is unstable. This study concentrates on high efficiency Double-Fed Induction Generators and Traditional Generators from mathematic model to derive and control the characteristics simulation and comparison than get an output of high efficiency Double-Fed Industrial Generators. This study utilizes the simulation software MATLAB/Simulink to simulate the response characteristics of vector control of a Double-Fed Industrial Generator. The operating and control functions are better than those of a traditional generator.

孤岛微电网多虚拟同步发电机频率无差协调控制策略

传统虚拟同步发电机的频率控制为有差控制,且虚拟惯量的引入使得虚拟同步发电机呈现二阶振荡特性,导致孤岛微电网多虚拟同步发电机并联系统在受到负荷扰动时面临频率偏移和有功超调的问题。针对此,提出了一种多虚拟同步发电机频率无差协调控制方法。该方法包含了兼具有功精确分配的频率无差调节控制和阻尼改进控制两部分,通过利用母线频率全局一致的“通信”效果,以分散式的形式协调系统内各台虚拟同步发电机,可主动消除微电网频率稳态偏差且实现各台虚拟同步发电机按照容量承担负荷有功功率,并抑制系统的有功超调。最后,通过仿真和实验验证了所提控制方法的有效性。

自适应调节有功功率偏差的虚拟同步发电机暂态控制策略

虚拟同步发电机(VSG)控制的并网逆变器在电网电压跌落时存在功角暂态失稳及过电流现象,为此提出一种VSG暂态控制策略。根据VSG功角特性,推导出有功功率与功角暂态稳定性之间的联系,并基于VSG暂态电流特性,分析VSG无功动态响应特性与暂态功角变化的关系。在此基础上,以角频率偏差、有功功率偏差及有功功率偏差变化率三者的正负作为功角特性曲线的区间划分依据,设计出有功功率偏差系数分段自适应调节策略,通过控制有功功率偏差抑制功角增大,并对VSG输出过电流进行抑制,基于等面积准则证明了VSG的暂态稳定性。仿真分析结果表明,采用所提控制策略能够有效消除VSG控制并网逆变器的功角暂态失稳及过电流现象,且无论暂态期间是否存在稳定运行平衡点,所提策略均可确保VSG功角稳定。

Study of Microturbine Models in Islanded and Grid-Connected Mode

Modeling and simulation of two different microturbine （MT） models to analyze load following performance as distributed energy resource （DER） have been presented in this paper. The first model consists of speed governor, acceleration control, and temperature control blocks while the other is GAST model. The system comprises a synchronous generator and a MT coupled to it. Simulations are carried out in islanded and grid-connected mode to observe the system response when supplying variable loads. The load following characteristics is observed and validated for this MT-synchronous generator model in Matlab-Simulink environment. This is applicable with combined heat power （CHP） generators both with general fuel as well as bio-fuels. The use of bio-fuels is very much promising for generating green power preventing green house gas emissions for fighting against global warming.

An Advanced Teaching Lab for the Setting up of an Islanded Production Unit

The present paper addresses an advanced teaching lab consisting of setting up an islanded production unit. This teaching lab takes place in the very last semester at master level for students in electrical engineering with energy specialization. The purpose of this teaching lab is to combine knowledge learned in different areas such as power electronics, control, electrical machines and networks, and make use of all of them in practice. The present paper describes in detail the different steps followed by the student to set up an islanded production unit.

考虑可再生能源接入的多端MMC交直流混合系统协调控制

模块化多电平变换器的零转动惯量特性,使其无法对交流电网的频率波动提供支撑,导致交直流混合系统的整体惯性下降,影响并网系统的动态性能与稳定性。文章将改进功率-电压下垂控制与虚拟同步机技术相结合,提出一种新型功率协调控制策略。在系统直流电压稳定的情况下,对交流电网进行频率调节,同时对各变换器间的功率进行合理分配,无需通讯系统即可建立有效的能量管理体系。与传统双闭环控制进行对比试验,结果表明,所提控制策略有效解决了系统由低惯量、欠阻尼引起的动态性能与稳定性的问题。