The present study was carried out in order to track the maximum power point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy. In this strategy, first, th...The present study was carried out in order to track the maximum power point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy. In this strategy, first, the rotor speed is set at an optimal point for different wind speeds. As a result of which, the tip speed ratio reaches an optimal point, mechanical power coefficient is maximized, and wind turbine produces its maximum power and mechanical torque. Then, the maximum mechanical torque is tracked using electromechanical torque. In this technique, tracking error integral of maximum mechanical torque, the error, and the derivative of error are used as state variables. During changes in wind speed, sliding mode control is designed to absorb the maximum energy from the wind and minimize the response time of maximum power point tracking(MPPT). In this method, the actual control input signal is formed from a second order integral operation of the original sliding mode control input signal. The result of the second order integral in this model includes control signal integrity, full chattering attenuation, and prevention from large fluctuations in the power generator output. The simulation results, calculated by using MATLAB/m-file software, have shown the effectiveness of the proposed control strategy for wind energy systems based on the permanent magnet synchronous generator(PMSG).展开更多
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 considerati...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.展开更多
This paper presents a comprehensive overview study of the DDPMSG （direct driven permanent magnet synchronous generator） for wind energy generation system. Wind turbine controls are provided. The PMSG （permanent mag...This paper presents a comprehensive overview study of the DDPMSG （direct driven permanent magnet synchronous generator） for wind energy generation system. Wind turbine controls are provided. The PMSG （permanent magnet synchronous generator） is introduced as construction and model. Configurations of different power converters are presented for use with DDPMSG in wind systems at variable speed operation and maximum power capture. Control techniques for the system are discussed for both machine-side and grid-side in details. Grid integration is provided with focus on how to insure power quality of the system and the performance at disturbances.展开更多
The high-speed simulation of large-scale offshore wind farms(OWFs) preserving the internal machine information has become a huge challenge due to the large wind turbine(WT) count and microsecond-range time step. Hence...The high-speed simulation of large-scale offshore wind farms(OWFs) preserving the internal machine information has become a huge challenge due to the large wind turbine(WT) count and microsecond-range time step. Hence, it is undoable to investigate the internal node information of the OWF in the electro-magnetic transient(EMT) programs. To fill this gap,this paper presents an equivalent modeling method for largescale OWF, whose accuracy and efficiency are guaranteed by integrating the individual devices of permanent magnet synchronous generator(PMSG) based WT. The node-elimination algorithm is used while the internal machine information is recursively updated. Unlike the existing aggregation methods, the developed EMT model can reflect the characteristics of each WT under different wind speeds and WT parameters without modifying the codes. The access to each WT controller is preserved so that the time-varying dynamics of all the WTs could be simulated. Comparisons of the proposed model with the detailed model in PSCAD/EMTDC have shown very high precision and high efficiency. The proposed modeling procedures can be used as reference for other types of WTs once the structures and parameters are given.展开更多
This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), pe...This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.展开更多
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...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.展开更多
The axial flux permanent magnet(AFPM)generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power density.The performance of the AFPM generator with do...The axial flux permanent magnet(AFPM)generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power density.The performance of the AFPM generator with double-sided internal stator structure can be improved by the reasonable design of electromagnetic parameters.To further improve the overall performance of the AFPM generator with double-sided internal stator structure,multivariable(coil widthω_(c),permanent magnet thickness h,pole arc coefficient α_(p) and working air gap l_(g))and multi-objective(generator efficiencyη,total harmonic distortion of the voltage THD and induced electromotive force amplitude EMF)functional relationships are innovatively established.Orthogonal analysis,mean analysis and variance analysis are performed on the influence parameters by combining the Taguchi method and response surface methodology to study the influence degrees of each influence parameter on the optimization objectives to determine the most appropriate electromagnetic parameters.The optimization results are verified by 3D finite element analysis.The optimized APFM generator with double-sided internal stator structure exhibits superior economy,stronger magnetic density,higher efficiency and improved power quality.展开更多
In addition to the characteristics of a conventional motor, a novel direct-drive double-stator permanent-magnet brushless motor proposed can operate in the state of either a generator or a motor as appropriate. Throug...In addition to the characteristics of a conventional motor, a novel direct-drive double-stator permanent-magnet brushless motor proposed can operate in the state of either a generator or a motor as appropriate. Through numerical calculation and analysis, the output torque of double-stator permanent-magnet brushless motor of the same volume as the traditional machine is discussed, and the reduction of torque ripple by using the structure features of this motor is investigated. The results indicate that lower torque ripple under the condition of ideal effective torque can be obtained by the rational design of motor. The prototype motors tested show that this kind of motor structure has a higher power density.展开更多
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. Vo...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.展开更多
Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnet...Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.展开更多
针对并网风电场中,经典一次调频控制方法存在抗干扰能力弱、机组易脱网的问题,提出一种基于滑模变结构的风电机组一次调频控制算法。首先,在永磁同步风电机组工作原理的基础上,建立含有大电网的风电机组模型。其次,为了解决传统比例积...针对并网风电场中,经典一次调频控制方法存在抗干扰能力弱、机组易脱网的问题,提出一种基于滑模变结构的风电机组一次调频控制算法。首先,在永磁同步风电机组工作原理的基础上,建立含有大电网的风电机组模型。其次,为了解决传统比例积分微分(proportional integral differential,PID)控制下抗干扰能力弱的问题、引入经典滑模变结构控制器。然后,针对经典滑模变结构控制器导致执行机构存在抖振较多的缺点,提出一种基于sigmoid函数趋近率的滑模变结构一次调频控制算法。最后,通过MATLAB/Simulink对风电机组一次调频进行建模仿真,并与经典控制算法相比,验证了所提算法的可行性,在风速波动和电网故障的环境下,滑模变结构一次调频控制算法更具有效性。展开更多
通过改进粒子群算法(particle swarm optimization,PSO)优化长短期记忆神经网络算法(long short-term memory,LSTM)的参数,提出了一种基于改进PSO-LSTM算法的直驱式风电机组运行状态监测方法。首先将数据采集与监控系统(supervisory con...通过改进粒子群算法(particle swarm optimization,PSO)优化长短期记忆神经网络算法(long short-term memory,LSTM)的参数,提出了一种基于改进PSO-LSTM算法的直驱式风电机组运行状态监测方法。首先将数据采集与监控系统(supervisory control and data acquisition,SCADA)采集到的数据利用随机森林的方法进行特征筛选,得到模型的输入参数;其次采用改进PSO-LSTM网络建立有功功率的预测模型,计算出预测值与实际值的残差,根据残差的分布来确实直驱式风电机组的状态;最后利用某风电机组SCADA数据对所提预测模型进行验证分析,结果表明,PSO-LSTM预测模型相比其他三种预测模型,具有较高的预测精度,并在状态异常后最短时间内发出故障警报,保证电场的健康稳定运行。展开更多
文摘The present study was carried out in order to track the maximum power point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy. In this strategy, first, the rotor speed is set at an optimal point for different wind speeds. As a result of which, the tip speed ratio reaches an optimal point, mechanical power coefficient is maximized, and wind turbine produces its maximum power and mechanical torque. Then, the maximum mechanical torque is tracked using electromechanical torque. In this technique, tracking error integral of maximum mechanical torque, the error, and the derivative of error are used as state variables. During changes in wind speed, sliding mode control is designed to absorb the maximum energy from the wind and minimize the response time of maximum power point tracking(MPPT). In this method, the actual control input signal is formed from a second order integral operation of the original sliding mode control input signal. The result of the second order integral in this model includes control signal integrity, full chattering attenuation, and prevention from large fluctuations in the power generator output. The simulation results, calculated by using MATLAB/m-file software, have shown the effectiveness of the proposed control strategy for wind energy systems based on the permanent magnet synchronous generator(PMSG).
文摘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.
文摘This paper presents a comprehensive overview study of the DDPMSG （direct driven permanent magnet synchronous generator） for wind energy generation system. Wind turbine controls are provided. The PMSG （permanent magnet synchronous generator） is introduced as construction and model. Configurations of different power converters are presented for use with DDPMSG in wind systems at variable speed operation and maximum power capture. Control techniques for the system are discussed for both machine-side and grid-side in details. Grid integration is provided with focus on how to insure power quality of the system and the performance at disturbances.
基金supported by the National Natural Science Foundation of China (No. 52277094)Science and Technology Project of China Huaneng Group Co.,Ltd.(No. HNKJ20-H88)。
文摘The high-speed simulation of large-scale offshore wind farms(OWFs) preserving the internal machine information has become a huge challenge due to the large wind turbine(WT) count and microsecond-range time step. Hence, it is undoable to investigate the internal node information of the OWF in the electro-magnetic transient(EMT) programs. To fill this gap,this paper presents an equivalent modeling method for largescale OWF, whose accuracy and efficiency are guaranteed by integrating the individual devices of permanent magnet synchronous generator(PMSG) based WT. The node-elimination algorithm is used while the internal machine information is recursively updated. Unlike the existing aggregation methods, the developed EMT model can reflect the characteristics of each WT under different wind speeds and WT parameters without modifying the codes. The access to each WT controller is preserved so that the time-varying dynamics of all the WTs could be simulated. Comparisons of the proposed model with the detailed model in PSCAD/EMTDC have shown very high precision and high efficiency. The proposed modeling procedures can be used as reference for other types of WTs once the structures and parameters are given.
文摘This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.
文摘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.
基金funded by Project Supported by Postdoctoral Science Foundation of Jiangsu Province,Grant No.2019k237.
文摘The axial flux permanent magnet(AFPM)generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power density.The performance of the AFPM generator with double-sided internal stator structure can be improved by the reasonable design of electromagnetic parameters.To further improve the overall performance of the AFPM generator with double-sided internal stator structure,multivariable(coil widthω_(c),permanent magnet thickness h,pole arc coefficient α_(p) and working air gap l_(g))and multi-objective(generator efficiencyη,total harmonic distortion of the voltage THD and induced electromotive force amplitude EMF)functional relationships are innovatively established.Orthogonal analysis,mean analysis and variance analysis are performed on the influence parameters by combining the Taguchi method and response surface methodology to study the influence degrees of each influence parameter on the optimization objectives to determine the most appropriate electromagnetic parameters.The optimization results are verified by 3D finite element analysis.The optimized APFM generator with double-sided internal stator structure exhibits superior economy,stronger magnetic density,higher efficiency and improved power quality.
文摘In addition to the characteristics of a conventional motor, a novel direct-drive double-stator permanent-magnet brushless motor proposed can operate in the state of either a generator or a motor as appropriate. Through numerical calculation and analysis, the output torque of double-stator permanent-magnet brushless motor of the same volume as the traditional machine is discussed, and the reduction of torque ripple by using the structure features of this motor is investigated. The results indicate that lower torque ripple under the condition of ideal effective torque can be obtained by the rational design of motor. The prototype motors tested show that this kind of motor structure has a higher power density.
文摘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.
基金National Natural Science Foundation of China,Grant/Award Numbers:11872222,11902173State Key Laboratory of Tribology,Grant/Award Number:SKLT2021D11。
文摘Dynamic characteristics of large permanent magnet direct‐drive generators(PMDGs)considering electromagnetic–structural coupling effects are analyzed in this study.Using the conformal mapping method,the scalar magnetic potential of the air gap magnetic field considering the slot effect is calculated.On the basis of the discrete current element and magnetic equivalent circuit model,the local magnetic saturation effect of the stator and rotor is quantitatively simulated and the air gap magnetic field intensity distribution is obtained via numerical simulation.A series of uniformly distributed equivalent electromagnetic springs are introduced to develop an electromagnetic–structural coupling finite element PMDG model.The proposed air gap field analysis method is verified by the finite element analysis results.On the basis of the test platform for the Goldwind 1.5MW PMDG,both modal and dynamic response tests for the stator/rotor coupling system are conducted,and the results are compared with the natural frequencies,mode shapes,and vibration responses obtained using the numerical model.The effects of the air gap length and rotor speed on the natural frequencies of the coupling system are analyzed.The proposed model has the potential to accurately evaluate the PMDG vibration energy,avoiding resonance points,and maintaining stable operations of the unit.
文摘针对并网风电场中,经典一次调频控制方法存在抗干扰能力弱、机组易脱网的问题,提出一种基于滑模变结构的风电机组一次调频控制算法。首先,在永磁同步风电机组工作原理的基础上,建立含有大电网的风电机组模型。其次,为了解决传统比例积分微分(proportional integral differential,PID)控制下抗干扰能力弱的问题、引入经典滑模变结构控制器。然后,针对经典滑模变结构控制器导致执行机构存在抖振较多的缺点,提出一种基于sigmoid函数趋近率的滑模变结构一次调频控制算法。最后,通过MATLAB/Simulink对风电机组一次调频进行建模仿真,并与经典控制算法相比,验证了所提算法的可行性,在风速波动和电网故障的环境下,滑模变结构一次调频控制算法更具有效性。
文摘通过改进粒子群算法(particle swarm optimization,PSO)优化长短期记忆神经网络算法(long short-term memory,LSTM)的参数,提出了一种基于改进PSO-LSTM算法的直驱式风电机组运行状态监测方法。首先将数据采集与监控系统(supervisory control and data acquisition,SCADA)采集到的数据利用随机森林的方法进行特征筛选,得到模型的输入参数;其次采用改进PSO-LSTM网络建立有功功率的预测模型,计算出预测值与实际值的残差,根据残差的分布来确实直驱式风电机组的状态;最后利用某风电机组SCADA数据对所提预测模型进行验证分析,结果表明,PSO-LSTM预测模型相比其他三种预测模型,具有较高的预测精度,并在状态异常后最短时间内发出故障警报,保证电场的健康稳定运行。
