The operation of a dynamic voltage restorer(DVR)is studied using a three-phase voltage source converter(VSC)-based topology to alleviate voltage anomalies from a polluted supply voltage.The control algorithm used incl...The operation of a dynamic voltage restorer(DVR)is studied using a three-phase voltage source converter(VSC)-based topology to alleviate voltage anomalies from a polluted supply voltage.The control algorithm used included two components.The first is an adaptive Takagi-Sugeno-Kang(TSK)-based adaptive reweighted L1 norm adaption-based normalized least mean square(TSK-ARNA-NLMS)unit,which is proposed for the extraction of fundamental active and reactive components from the non-ideal supply and is further employed to generate the load reference voltage and switching pulse for the VSC.The step size was evaluated using the proposed TSK-ARNA-NLMS controller,and the TSK unit was optimized by integration with the marine predator algorithm(MPA)for a faster convergence rate.The second,a fractional-order PID controller(FOPID),was employed for AC-and DC-link voltage regulation and was approximated using the Oustaloup technique.The FOPID()PI Dγμprovides more freedom for tuning the settling time,rise time,and overshoot.The FOPID coefficients(Ki,Kd,Kp,γ,andμ)were optimized by employing an advanced ant lion optimization(ALO)meta-heuristics technique to minimize the performance index,namely,the integral time absolute error(ITAE)and assess the accuracy of controllers.The DVR performance was validated under dynamic-and steady-state conditions.展开更多
An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, an...An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, and high quality transient characteristics of the integral terminal sliding mode control with the estimation properties of disturbance observers. The controller gains were auto-tuned using a fuzzy logic approach.The effectiveness of the proposed design was assessed under deep voltage sag conditions and parameter variations. Its dynamic response was also compared to that of a standard SMC approach.The performance analysis and simulation results confirmed the ability of the proposed approach to maintain the active power,currents, DC-link voltage and electromagnetic torque within their acceptable ranges even under the most severe unbalanced voltage conditions. It was also shown to be robust to uncertainties and parameter variations, while effectively mitigating chattering in comparison with the standard SMC.展开更多
The study of damage in rotating machineries is of fundamental interest in the fields of machine and structure design. A rotating system, supported by bearings and under some dynamic conditions, can generate a variety ...The study of damage in rotating machineries is of fundamental interest in the fields of machine and structure design. A rotating system, supported by bearings and under some dynamic conditions, can generate a variety of problems that are encountered in many different types of rotating machines. One of these problems is the unbalance due to non-homogeneous mass distribution along the shaft. One of the techniques which are widespread today is the identification of parameters and excitation forces that may well followed by monitoring the evolution and change of possible variations of these parameters. Although several methods for the identification of unbalance excitation force are available in the literature, none of them can be considered unrestricted to be applied for all rotating systems. In this study, two methodologies to identify unknown excitations, such as unbalance, have been proposed. This project refers to the analysis of unbalanced forces from displacement parameters and speed by using methods of identification by Fourier series and Legendre polynomials together with the finite element method, state observers in reasons of the problem of absence of signs of rotational displacement, bandpass filter were used to noise suppression of the data collected from the experimental part, Quasi-Newton method to minimize a function in which the bearing stiffness and its damping are unknowns, and also the experimental verification of the methodology, using for this system owned by a rotary mechanical vibrations of the Department of Mechanical Engineering of Faculty of Engineering, campus of llha Solteira.展开更多
为了满足并网变流器在电网电压不对称情况下的控制需求,需要快速准确地提取出基波正负序分量的幅值和相位。在电网电压不对称时,负序分量会在同步参考坐标系锁相环(phase locked loop based on synchronization reference frame,SRF-PLL...为了满足并网变流器在电网电压不对称情况下的控制需求,需要快速准确地提取出基波正负序分量的幅值和相位。在电网电压不对称时,负序分量会在同步参考坐标系锁相环(phase locked loop based on synchronization reference frame,SRF-PLL)的dq轴分量中产生2倍工频波动,影响基波分量和相位的提取结果。该文通过将自适应陷波器(adaptive notch filter,ANF)加入到同步参考坐标系锁相环的结构中,提出了一种能够实现正负序分量分离的自适应陷波器锁相环(phase locked loop with ANF,ANF-PLL)方法。该方法利用ANF陷波器的2个相互正交的输出量分别抵消电网电压dq轴分量中由于负序分量造成的2倍工频波动,以此消除了电网电压不对称对同步信号检测的影响,并且可以同时提取出基波负序分量的幅值和相位。与其它方法相比,该方法无需进行正负序解耦或瞬时对称分量分离,在单同步参考坐标系下实现了基波正负序分量的分离提取,结构更加简单,减少了计算量。实验结果表明,文中提出的方法能够在电网电压不对称与频率变化的情况下准确提取出基波正负序分量的幅值与相位,并且具有良好的动态性能。展开更多
文摘The operation of a dynamic voltage restorer(DVR)is studied using a three-phase voltage source converter(VSC)-based topology to alleviate voltage anomalies from a polluted supply voltage.The control algorithm used included two components.The first is an adaptive Takagi-Sugeno-Kang(TSK)-based adaptive reweighted L1 norm adaption-based normalized least mean square(TSK-ARNA-NLMS)unit,which is proposed for the extraction of fundamental active and reactive components from the non-ideal supply and is further employed to generate the load reference voltage and switching pulse for the VSC.The step size was evaluated using the proposed TSK-ARNA-NLMS controller,and the TSK unit was optimized by integration with the marine predator algorithm(MPA)for a faster convergence rate.The second,a fractional-order PID controller(FOPID),was employed for AC-and DC-link voltage regulation and was approximated using the Oustaloup technique.The FOPID()PI Dγμprovides more freedom for tuning the settling time,rise time,and overshoot.The FOPID coefficients(Ki,Kd,Kp,γ,andμ)were optimized by employing an advanced ant lion optimization(ALO)meta-heuristics technique to minimize the performance index,namely,the integral time absolute error(ITAE)and assess the accuracy of controllers.The DVR performance was validated under dynamic-and steady-state conditions.
文摘An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, and high quality transient characteristics of the integral terminal sliding mode control with the estimation properties of disturbance observers. The controller gains were auto-tuned using a fuzzy logic approach.The effectiveness of the proposed design was assessed under deep voltage sag conditions and parameter variations. Its dynamic response was also compared to that of a standard SMC approach.The performance analysis and simulation results confirmed the ability of the proposed approach to maintain the active power,currents, DC-link voltage and electromagnetic torque within their acceptable ranges even under the most severe unbalanced voltage conditions. It was also shown to be robust to uncertainties and parameter variations, while effectively mitigating chattering in comparison with the standard SMC.
文摘The study of damage in rotating machineries is of fundamental interest in the fields of machine and structure design. A rotating system, supported by bearings and under some dynamic conditions, can generate a variety of problems that are encountered in many different types of rotating machines. One of these problems is the unbalance due to non-homogeneous mass distribution along the shaft. One of the techniques which are widespread today is the identification of parameters and excitation forces that may well followed by monitoring the evolution and change of possible variations of these parameters. Although several methods for the identification of unbalance excitation force are available in the literature, none of them can be considered unrestricted to be applied for all rotating systems. In this study, two methodologies to identify unknown excitations, such as unbalance, have been proposed. This project refers to the analysis of unbalanced forces from displacement parameters and speed by using methods of identification by Fourier series and Legendre polynomials together with the finite element method, state observers in reasons of the problem of absence of signs of rotational displacement, bandpass filter were used to noise suppression of the data collected from the experimental part, Quasi-Newton method to minimize a function in which the bearing stiffness and its damping are unknowns, and also the experimental verification of the methodology, using for this system owned by a rotary mechanical vibrations of the Department of Mechanical Engineering of Faculty of Engineering, campus of llha Solteira.
文摘为了满足并网变流器在电网电压不对称情况下的控制需求,需要快速准确地提取出基波正负序分量的幅值和相位。在电网电压不对称时,负序分量会在同步参考坐标系锁相环(phase locked loop based on synchronization reference frame,SRF-PLL)的dq轴分量中产生2倍工频波动,影响基波分量和相位的提取结果。该文通过将自适应陷波器(adaptive notch filter,ANF)加入到同步参考坐标系锁相环的结构中,提出了一种能够实现正负序分量分离的自适应陷波器锁相环(phase locked loop with ANF,ANF-PLL)方法。该方法利用ANF陷波器的2个相互正交的输出量分别抵消电网电压dq轴分量中由于负序分量造成的2倍工频波动,以此消除了电网电压不对称对同步信号检测的影响,并且可以同时提取出基波负序分量的幅值和相位。与其它方法相比,该方法无需进行正负序解耦或瞬时对称分量分离,在单同步参考坐标系下实现了基波正负序分量的分离提取,结构更加简单,减少了计算量。实验结果表明,文中提出的方法能够在电网电压不对称与频率变化的情况下准确提取出基波正负序分量的幅值与相位,并且具有良好的动态性能。
