This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular wa...This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular waves’ behavior is predicted by Kalman filter method. Owing to the great influence of controller parameters on the absorbed power, these parameters are optimized by imperialist competitive algorithm. The results illustrate the method’s efficiency in maximizing the extracted power in the presence of unknown excitation force which should be predicted by Kalman filter.展开更多
This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generat...This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.展开更多
Ocean wave propagation is slow, visible and measurable, so a wave theory can be used to approximately predict the imminnent wave force on an offshore structure based on measured, real-time wave elevation near the stru...Ocean wave propagation is slow, visible and measurable, so a wave theory can be used to approximately predict the imminnent wave force on an offshore structure based on measured, real-time wave elevation near the structure. This predictability suggests the development of a more efficient algorithm, than those that have been developed for structures under wind and seismic loads, for the active vibration control of offshore structures. The present study delveops a mutiple-step predictive optimal control (MPOC) algorithm that accounts for multiple step external loading in the determination of optimal control forces. The control efficiency of the newly developed MPOC algorithm has been Investigated under both regular (single-frequency) and irregular (multiple-frequency) wave loads, and compared with that of two other well-known optimal control algorithms: classical linear optimal control(CLOC) and instantaneous optimal control(IOC).展开更多
This paper presents an extended model predictive controller for maximizing the absorbed power of a point absorber wave energy converter. Owing to the great influence of controller parameters upon the absorbed power, t...This paper presents an extended model predictive controller for maximizing the absorbed power of a point absorber wave energy converter. Owing to the great influence of controller parameters upon the absorbed power, the optimization of these parameters is carried out for the first time by a firefly algorithm(FA). Error, the difference between output velocity of buoy and input wave speed which leads to power maximization in the optimized MPC is compared with the classical MPC. Simulation results indicate that given the high accuracy and acceptable speed of the algorithm, it can adjust the parameters of the controller to the point where system error decreased effectively and the absorbed energy increased about 4 MW.展开更多
针对现有主动悬架在应用最优控制时缺乏路面扰动识别内容的问题,提出一种识别路面扰动反馈的最优控制器。该控制器在传统系统状态反馈最优控制的基础上引入扰动反馈项,并通过粒子群算法优化加权系数,同时采用直线电机作为作动器。考虑...针对现有主动悬架在应用最优控制时缺乏路面扰动识别内容的问题,提出一种识别路面扰动反馈的最优控制器。该控制器在传统系统状态反馈最优控制的基础上引入扰动反馈项,并通过粒子群算法优化加权系数,同时采用直线电机作为作动器。考虑到路面不平度与系统状态响应获取存在先后顺序,采用开环带有外部输入的非线性自回归(Nonlinear Auto-regressive Model with Exogenous Inputs,NARX)神经网络预测与逆模型相结合的方法来识别路面不平度。神经网络离线训练在线识别,识别模块实时将结果传输给控制器。在整车模型上对控制策略进行仿真。结果表明,粒子群优化使平顺性指标显著改善;采用的路面识别方法可有效提高识别的精确性;与不识别扰动控制相比,本策略可有效降低悬架动挠度的恶化,并改善整体控制效果。展开更多
舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算...舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算法中引入抑制因子,对主动控制力的输出进行限幅。首先通过数值仿真分析验证匹配优化后的控制算法对振动控制的抑制效果,然后介绍基于电磁主动吸振器工程样机搭建的主动控制实验台架系统,以单频激励工况为基础开展主动控制效果验证实验,证明电磁吸振器与匹配优化后的控制算法对低频机械振动控制的有效性。数值仿真和实验结果表明,针对自主设计研制的电磁主动吸振器而提出的匹配优化主动控制算法能够有效抑制低频机械振动响应,在时域和频域均可以取得显著的振动控制效果。展开更多
文摘This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular waves’ behavior is predicted by Kalman filter method. Owing to the great influence of controller parameters on the absorbed power, these parameters are optimized by imperialist competitive algorithm. The results illustrate the method’s efficiency in maximizing the extracted power in the presence of unknown excitation force which should be predicted by Kalman filter.
文摘This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.
基金National Science Foundation of U.S.A.under grant CMS-9503533
文摘Ocean wave propagation is slow, visible and measurable, so a wave theory can be used to approximately predict the imminnent wave force on an offshore structure based on measured, real-time wave elevation near the structure. This predictability suggests the development of a more efficient algorithm, than those that have been developed for structures under wind and seismic loads, for the active vibration control of offshore structures. The present study delveops a mutiple-step predictive optimal control (MPOC) algorithm that accounts for multiple step external loading in the determination of optimal control forces. The control efficiency of the newly developed MPOC algorithm has been Investigated under both regular (single-frequency) and irregular (multiple-frequency) wave loads, and compared with that of two other well-known optimal control algorithms: classical linear optimal control(CLOC) and instantaneous optimal control(IOC).
文摘This paper presents an extended model predictive controller for maximizing the absorbed power of a point absorber wave energy converter. Owing to the great influence of controller parameters upon the absorbed power, the optimization of these parameters is carried out for the first time by a firefly algorithm(FA). Error, the difference between output velocity of buoy and input wave speed which leads to power maximization in the optimized MPC is compared with the classical MPC. Simulation results indicate that given the high accuracy and acceptable speed of the algorithm, it can adjust the parameters of the controller to the point where system error decreased effectively and the absorbed energy increased about 4 MW.
文摘针对现有主动悬架在应用最优控制时缺乏路面扰动识别内容的问题,提出一种识别路面扰动反馈的最优控制器。该控制器在传统系统状态反馈最优控制的基础上引入扰动反馈项,并通过粒子群算法优化加权系数,同时采用直线电机作为作动器。考虑到路面不平度与系统状态响应获取存在先后顺序,采用开环带有外部输入的非线性自回归(Nonlinear Auto-regressive Model with Exogenous Inputs,NARX)神经网络预测与逆模型相结合的方法来识别路面不平度。神经网络离线训练在线识别,识别模块实时将结果传输给控制器。在整车模型上对控制策略进行仿真。结果表明,粒子群优化使平顺性指标显著改善;采用的路面识别方法可有效提高识别的精确性;与不识别扰动控制相比,本策略可有效降低悬架动挠度的恶化,并改善整体控制效果。
文摘舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算法中引入抑制因子,对主动控制力的输出进行限幅。首先通过数值仿真分析验证匹配优化后的控制算法对振动控制的抑制效果,然后介绍基于电磁主动吸振器工程样机搭建的主动控制实验台架系统,以单频激励工况为基础开展主动控制效果验证实验,证明电磁吸振器与匹配优化后的控制算法对低频机械振动控制的有效性。数值仿真和实验结果表明,针对自主设计研制的电磁主动吸振器而提出的匹配优化主动控制算法能够有效抑制低频机械振动响应,在时域和频域均可以取得显著的振动控制效果。
