【作者】 张健；

【导师】 刘延俊；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2018， 博士

【摘要】 随着社会发展,常规能源已不能满足社会的需求,波浪能是海洋中储量最丰富的一种能源,以其无污染、可再生等特点得到重视,对其开发力度也在逐步增加,我国对波浪能开发刚刚开始,很多问题等待解决。旋转式波浪能发电装置传动部位往往需要进行密封,传统的密封方式无法实现完全密封,会随着运行慢慢失效,导致设备故障。磁性驱动器常被用在对密封要求很高的场合,像化工厂、制药厂等,能满足严格的密封要求。本论文以适用于波浪能发电设备的磁性驱动器的传动机理分析与变阻尼控制为主要目标,结合等效磁荷法、拉格朗日方程等对磁性驱动器的性能进行研究,将磁性驱动器引入波浪能发电装置中,拓宽磁性驱动器的应用领域。本文介绍了国内外海洋能装置密封机构发展状况,分析了磁性驱动器的发展情况及其理论研究。以磁性驱动器为研究对象,依据磁力驱动技术、机械设计理论、现代控制理论等,对其进行了建模、理论研究和实验分析。基于等效磁荷法,建立了磁性驱动器的理论模型,讨论不同条件下,磁性驱动器的扭矩传递情况,分析了存在安装偏差情况下磁性驱动器的理论模型。以矩形磁体为例进行了详细理论推导,得出了扭矩传递的数学解析式,为后面的分析奠定了基础。建立磁性驱动器通用数学模型,根据磁性驱动器磁体离散特性及结构参数,得到磁性驱动器的扭矩解析方程,对磁性驱动器在不同磁极数、半径、磁体尺寸等参数下的扭矩传递性能进行分析,得出磁性驱动器性能随各参数变化的特性曲线,为磁性驱动器性能分析和优化奠定了基础。建立磁性驱动器的分析模型,通过有限元分析法证实了理论可行性。结果表明当磁体对数增加到一定数目时才能对磁性驱动器性能有较好的提升,磁体宽度与半径存在一个最佳相对值,磁体数目的增加能提高磁性驱动器的扭转刚度,增强磁性驱动器的动态响应性能。磁性驱动器传递的扭矩与磁体的宽度、厚度、长度呈正相关关系,与磁体间的气隙呈负相关关系,最大传递扭矩与半径呈抛物线关系。对磁性驱动器安装偏差进行分析表明径向偏差对其性能影响较小,会稍微提高磁性驱动器的扭矩传递能力;轴向偏差对磁性驱动器影响较大,使磁性驱动器的扭矩传递能力迅速下降,过大的轴向偏差会使其失去扭矩传递能力。引入拉格朗日方程到磁性驱动器动力学性能研究中,建立了磁性驱动器动力学方程,得到了磁性驱动器动态性能的数学模型,分析了不同参数对磁性驱动器动态性能的影响,得到了扭转刚度、转动惯量、阻尼系数与磁性驱动器动力学性能的关系,讨论了在不同外界条件下磁性驱动器的响应性能。通过实验采集了波浪能发电设备的结构参数,建立了水轮机的有限元分析模型,依据实际波浪条件,对水轮机的运行情况进行了有限元分析,建立了不同条件下的水轮机运动特性。将水轮机的运动特性作为输入条件,对磁性驱动器的动力学性能进行分析,得到了磁性驱动器的响应特性。结果表明增加扭转刚度可以提高磁性驱动器的响应性能,缩短从动转子的响应时间,增强磁性驱动器的启动性能;减小阻尼系数会使输出端的振荡增加,调节时间变长,但会缩短输出端的响应时间;增加转动惯量使输出端的启动特性变差,稳定时间增加,输出端的抖动变大;系统的稳态性能与磁性驱动器的转动惯量无关,仅受到阻尼系数和扭转刚度的影响。基于空间状态法,建立了磁性驱动器的空间状态方程,得到了磁性驱动器的各个运动变量的数学表达式,分析了磁性驱动器在运行过程中的稳定性。根据磁性驱动器动力学特性方程,考虑安装偏差存在时,以磁性驱动器输入端与输出端的角度差为衡量指标,建立了磁性驱动器角度差特性方程,分析了在不同转动惯量、扭转刚度和阻尼系数下,磁性驱动器的角度差变化。结果显示转动惯量增加和扭转刚度增加使磁性驱动器的角度差的瞬态性能变差,阻尼系数增加使角度差瞬态性能变好,过大的阻尼系数会使磁性驱动器稳态时角度差变大。根据不同参数对角度差性能的影响,提出了一种变阻尼系数控制方法,使磁性驱动器获得较好的动力学性能,依据这种控制方法设计了一种变阻尼系数控制器,通过有限元法验证了其可行性。研制了测量磁性驱动器扭矩传递性能和动力学性能的实验台,对磁性驱动器的扭矩传递性能和动力学性能进行了实验。通过设计的变阻尼系数控制器,对磁性驱动器的角度差脉动抑制性能进行了实验,验证了变阻尼系数法的可行性。实验结果表明,理论分析和实验偏差都在6%以内,能够满足实际工程要求,通过实验验证了前面章节理论分析的正确性。更多还原

【Abstract】 The demand for energy has been growing rapidly as a result of the fast development of society.Because of the depletion of fossil fuels and its pollution to environment,the demand of high-quality,clean and renewable energy source is particularly urgent.Wave energy is the most abundant source of ocean energy and shows advantages of high density,wide scope and renewability.The development of wave energy is at the starting phase in China and many technical problems remain to be solved.The transmission part in rotating wave energy converters needs to be sealed completely.However,the traditional sealing methods cannot assure this and will fail during long-term operation causing equipment failure.Magnetic driver,on the other hand,can guarantee complete sealing and is widely used where the requirement for sealing is high,such as in chemical plant and pharmaceutical factory.The main objective of this thesis study is to analyze the transmission mechanism and variable damping control of magnetic driver for wave energy converters.Equivalent magnetic charge method and Lagrange equations were used to analyze the magnetic driver.The magnetic driver was introduced into the wave energy converters to expand its application fields further.This thesis introduces the sealing mechanism development status of domestic and international ocean energy converters,analyses the development of magnetic driver and its theory.The object of study is the magnetic driver,which was modeled,studied theoretically and experimentally based on magnetic drive technology,mechanical design theory and modern control theory.Theoretical analysis model was built based on equivalent magnetic charge method and the transmitted torque of the magnetic driver was discussed under different conditions.Taking rectangular magnet as an example,the detailed theoretical derivation was carried out with general mathematical expression which laid a foundation for later analysis.The torque equation of the magnetic driver was derived based on the discrete characteristics and structural parameters of magnet.The thesis analyzed the torque transfer performance of the magnetic driver under different parameters such as pole numbers,radii and magnet sizes.Then the characteristic curve of magnetic driver varying with different parameters was obtained,which laid a foundation for the analysis and optimization of magnetic driver’s performance.The finite element analysis model of magnetic driver was built to verify the mathematical analysis.Results showed that magnetic driver had a good performance when poles increased to a certain number.There was a best relative value between magnet width and radius.Increasing the number of magnet pole could improve the torsional rigidity and enhance the dynamics performance.The transmitted torque was positively related to the magnet width,thickness and length while negatively related to the air gap.The relationship between the maximum transmitted torque and the radius was parabolic.The analysis of installation deviation showed that the radial deviation had little influence on the magnetic driver performance and could slightly improve the torque transmission ability.However,the axial deviation had a great impact on magnetic driver performance and caused rapid decrease of torque transmission capability.The overly large axial deviation would even make the magnetic driver fail to transfer torque.Lagrange equation was used to build the dynamics performance equation of magnetic driver in this thesis.The influences of torsional stiffness,moment of inertia,damping coefficient on the dynamics performance of magnetic driver were analyzed and the response performance of magnetic driver in different external conditions were discussed.The finite element analysis model of hydraulic turbine was built according to the structural parameter of the wave energy converter.According to actual wave condition,the hydraulic turbine was simulated and analyzed,so as to obtain its kinematic characteristics.Then the dynamics performance of magnetic driver was analyzed based on its kinematic characteristics.Results showed that the increase of torsional rigidity could enhance the response of magnetic driver,shorten the response time of the driven rotor,and improve the driver’s initiation performance.The increase of rotating inertia worsened the starting characteristic,and cost more time to stabilize.The decrease of damping coefficient could cause more output oscillation and prolong the adjust time,but it would shorten the response time of the output.The steady-state performance of the magnetic driver had nothing to do with its rotating inertia and was only affected by damping coefficient and torsional rigidity.The state space equation of the magnetic driver was built based on the State Space Method by which the mathematical expressions of various motion variables were obtained and the operation stability was analyzed.According to the dynamic equation and the installation deviation of magnetic driver,the angle difference equation used to measure the dynamics performance of magnetic driver was derived.The influences of the rotating inertia,the damping coefficient and the torsional rigidity on angle difference were analyzed.Results showed that the increase of the rotating inertia and the torsional rigidity worsened the transient performance of angle difference while the increase of the damping coefficient could improve it,but overly large damping coefficient enlarged stable angle difference.A variable damping coefficient control method was presented according to the above analysis,which improved the dynamics performance of magnetic driver.According to this method,a variable damping controller was designed and its feasibility was verified by the finite element method.The experimental prototype was manufactured to measure the torque transfer performance and dynamics performance of magnetic driver.Using the designed controller,the thesis tested the angle difference fluctuation suppression performance and the feasibility of the variable damping coefficient method.The experimental results showed that the deviation between theoretical analysis and experimental results was within 6%.Therefore,the theoretical equations met the engineering requirements and the theoretical analysis in the previous chapters was proved correct.更多还原