The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the ...The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC.It also depends on the efficiency of the power take-off system(PTO).This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching.The PTO characteristics,such as the gear ratio,the flywheel inertia,and the electric generator,are analyzed in the WEC performance.Three cylindrical point absorbers are also considered in the present study.A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves.The wave energy converter(WEC)performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied.The latching control system increases the mean power.However,the increase is not significant if the parameters that characterize the WEC provide a considerable mean power.The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel.However,the gear ratio shows a more significant influence than the flywheel inertia.The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance.展开更多
垂直起降飞行器(vertical take-off and landing,VTOL)是典型的非线性、欠驱动系统,实际工程中VTOL飞行器的执行机构通常有饱和特性,针对这种模型的特点,对原始数学模型进行了解耦坐标变换,通过可逆坐标变换化成一个最小相位系统和一个...垂直起降飞行器(vertical take-off and landing,VTOL)是典型的非线性、欠驱动系统,实际工程中VTOL飞行器的执行机构通常有饱和特性,针对这种模型的特点,对原始数学模型进行了解耦坐标变换,通过可逆坐标变换化成一个最小相位系统和一个非最小相位系统,之后采用滑模设计方法设计控制器。为了解决执行机构的饱和问题,将超出饱和受限的部分回馈到控制器中,构造一个赫尔伍兹稳定的辅助线性系统,然后把它加入到滑模控制器之中,在控制器中做补偿。利用李雅普诺夫函数证明了系统的稳定性。仿真结果表明,此方法可有效地解决输入受限的VTOL飞行器的镇定和轨迹跟踪问题。展开更多
基金The authors acknowledge the support from the Brazilian Research Council(CNPq),contract numbers 380950/2018-9(INEOF-National Institute for Ocean and River Energy)and 305657/2017-8,respectivelySpecial thanks to FAPERJ for the support of the wave energy research at the Subsea Technology Lab(COPPE),contract number E-26/202.600/2019。
文摘The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC.It also depends on the efficiency of the power take-off system(PTO).This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching.The PTO characteristics,such as the gear ratio,the flywheel inertia,and the electric generator,are analyzed in the WEC performance.Three cylindrical point absorbers are also considered in the present study.A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves.The wave energy converter(WEC)performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied.The latching control system increases the mean power.However,the increase is not significant if the parameters that characterize the WEC provide a considerable mean power.The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel.However,the gear ratio shows a more significant influence than the flywheel inertia.The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance.
文摘垂直起降飞行器(vertical take-off and landing,VTOL)是典型的非线性、欠驱动系统,实际工程中VTOL飞行器的执行机构通常有饱和特性,针对这种模型的特点,对原始数学模型进行了解耦坐标变换,通过可逆坐标变换化成一个最小相位系统和一个非最小相位系统,之后采用滑模设计方法设计控制器。为了解决执行机构的饱和问题,将超出饱和受限的部分回馈到控制器中,构造一个赫尔伍兹稳定的辅助线性系统,然后把它加入到滑模控制器之中,在控制器中做补偿。利用李雅普诺夫函数证明了系统的稳定性。仿真结果表明,此方法可有效地解决输入受限的VTOL飞行器的镇定和轨迹跟踪问题。
