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T型逆变器中点电压全范围精确平衡研究 被引量:9
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作者 李敏裕 马晓军 +1 位作者 魏曙光 张杰 《电工技术学报》 EI CSCD 北大核心 2018年第8期1814-1826,共13页
中点电压不平衡是T型逆变器的固有缺点。分别建立空间矢量脉宽调制(SVPWM)算法和虚拟空间矢量脉宽调制(VSVPWM)算法的中点电压偏移量数学模型,得到两种算法的中点电压不可平衡区域与负载功率因数角、调制比之间的关系,提出一种中点电压... 中点电压不平衡是T型逆变器的固有缺点。分别建立空间矢量脉宽调制(SVPWM)算法和虚拟空间矢量脉宽调制(VSVPWM)算法的中点电压偏移量数学模型,得到两种算法的中点电压不可平衡区域与负载功率因数角、调制比之间的关系,提出一种中点电压全范围精确平衡算法。该算法通过计算和修正小矢量作用时间的平衡因子来实现中点电压的精确平衡,通过判断平衡因子的取值来确定控制算法,以确保在保持中点电压精确平衡的基础上有效减小输出谐波和开关损耗,仿真和实验验证了所提算法的有效性。 展开更多
关键词 T型逆变器 三电平 中点电压不平衡 精确平衡
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whitham-Broer-Kaup方程新的精确解 被引量:1
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作者 杨琼芬 杨立娟 罗守双 《绵阳师范学院学报》 2017年第11期8-10,共3页
本文以其次平衡原则和试探函数法为基础,由Riccati方程的解得到了whitham-Broer-Kaup浅水波方程组的通解和精确解。
关键词 WBK方程 RICCATI方程 齐次平衡法和精确
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基于Midas Civil悬索桥荷载试验模型建立思路分析
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作者 雷民 《交通科技与管理》 2023年第6期7-9,共3页
以贵州某高速公路悬索桥为研究对象,通过MidasCivil进行荷载试验模型建立。模型建立根据悬索桥结构特点将主要构件进行合理拆分单独建模,最后合并模型成结构整体。计算结果表明该桥平衡态收敛误差满足要求,主缆、吊索无应力计算长度与... 以贵州某高速公路悬索桥为研究对象,通过MidasCivil进行荷载试验模型建立。模型建立根据悬索桥结构特点将主要构件进行合理拆分单独建模,最后合并模型成结构整体。计算结果表明该桥平衡态收敛误差满足要求,主缆、吊索无应力计算长度与设计对比分析误差较小,该桥的建模思路对试验检测单位建立悬索桥荷载试验模型提供借鉴。 展开更多
关键词 前处理 建模助手 初步找形 精确平衡分析 验证平衡
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基于DOB的炮管RBF神经网络滑模控制研究 被引量:2
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作者 陈宇政 高强 +2 位作者 侯远龙 瞿生鹏 胡继辉 《火炮发射与控制学报》 北大核心 2017年第4期24-29,共6页
针对坦克炮身管精确定位和平衡问题,提出了一种基于干扰观测器(DOB)的RBF神经网络滑模控制策略。由于炮控身管平衡系统模型中存在某些时变的不确定参数,所以利用RBF神经网络的万能逼近特性来辨识该参数。为了更好地提升系统的抗干扰性能... 针对坦克炮身管精确定位和平衡问题,提出了一种基于干扰观测器(DOB)的RBF神经网络滑模控制策略。由于炮控身管平衡系统模型中存在某些时变的不确定参数,所以利用RBF神经网络的万能逼近特性来辨识该参数。为了更好地提升系统的抗干扰性能,引入了干扰观测器,对系统外部扰动进行实时观测。通过仿真试验可知,该控制策略有效地提高了系统的稳定性,消除了滑模控制过程中固有的抖振现象,并大大提高了电液伺服系统的跟踪性能,使系统具有良好的鲁棒性。 展开更多
关键词 自动控制技术 身管精确定位和平衡 干扰观测器 RBF神经网络滑模 鲁棒性
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一台300MW汽轮发电机组汽封改造后振动故障诊断及处理 被引量:1
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作者 王双童 王晋权 《江苏电机工程》 2009年第3期15-17,共3页
介绍了一台300 MW机组经过汽封改造后,启动过程中产生异常振动的情况。通过对机组开机全过程的振动监测,对振动数据分析研究,确诊了振动故障的原因,经过对高中压转子返厂精确动平衡及汽封间隙调整处理,使机组顺利投运。
关键词 汽封改造 精确平衡 消振
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Direct Reduction and Exact Solutions for Generalized Variable Coefficients 2D KdV Equation under Some Integrability Conditions 被引量:2
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作者 M.H.M.Moussa RehabM.El-Shiekh 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第4期551-554,共4页
Based on the closed connections among the homogeneous balance (HB) method and Clarkson-KruSkal (CK) method, we study the similarity reductions of the generalized variable coefficients 2D KdV equation. In the meant... Based on the closed connections among the homogeneous balance (HB) method and Clarkson-KruSkal (CK) method, we study the similarity reductions of the generalized variable coefficients 2D KdV equation. In the meantime it is shown that this leads to a direct reduction in the form of ordinary differential equation under some integrability conditions between the variable coefficients. Two different cases have been discussed, the search for solutions of those ordinary differential equations yielded many exact travelling and solitonic wave solutions in the form of hyperbolic and trigonometric functions under some constraints between the variable coefficients. 展开更多
关键词 direct reduction method the generalized variable coefficients 2D KdV equation exact solutions
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Exact Solutions for the Generalized KdV Equation: Modified Homogeneous Balance Method
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作者 WANG Xiu-mei ZHU Yue-feng 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第2期260-269,共10页
In this paper, we present a solution methodology to obtain exact solutions of some nonlinear evolution equation by modifying the homogeneous balance method. Based on the modified homogeneous balance method, several ki... In this paper, we present a solution methodology to obtain exact solutions of some nonlinear evolution equation by modifying the homogeneous balance method. Based on the modified homogeneous balance method, several kinds of exact(new) solutions of the generalized KdV equation are obtained. 展开更多
关键词 generalized KdV equation modified homogeneous balance method exact solutions
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New Exact Solutions and Special Coherent Structures for Coupled Integrable Dispersionless Equation
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作者 Naranmandula 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第6期1037-1041,共5页
Using improved homogeneous balance method, we obtain new exact solutions for the coupled integrable dispersionless equation. On the basis of these exact solutions, we find some new interesting coherent structures by s... Using improved homogeneous balance method, we obtain new exact solutions for the coupled integrable dispersionless equation. On the basis of these exact solutions, we find some new interesting coherent structures by selecting arbitrary functions appropriately. 展开更多
关键词 exact solution coherent structure coupled integrable dispersionless equation improved homogeneous balance method
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重型立式加工中心龙门架设计
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作者 马伟良 姜辉 +2 位作者 李立强 石志民 郝峻崧 《制造技术与机床》 CSCD 北大核心 2011年第12期121-122,共2页
对重型立式加工中心龙门架的立柱导轨结构和横梁平衡装置进行技术改进,将立柱一字型导轨结构改进为阶梯导轨结构,使横梁升降丝杠的中心和横梁重心重合,使横梁处于最佳受力状态。将横梁机械重锤平衡结构改进为双油缸平衡结构,数控系统可... 对重型立式加工中心龙门架的立柱导轨结构和横梁平衡装置进行技术改进,将立柱一字型导轨结构改进为阶梯导轨结构,使横梁升降丝杠的中心和横梁重心重合,使横梁处于最佳受力状态。将横梁机械重锤平衡结构改进为双油缸平衡结构,数控系统可精确控制横梁两侧平衡力的大小,从而精确控制固定在垂直刀架滑枕上刀尖的位置,提高机床X轴、W轴的数控精度。 展开更多
关键词 双油缸 精确控制平衡 阶梯导轨 最佳受力状态
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On an Auto-Baecklund Transformation for (2+1)-Dimensional VariableCoefficient Generalized KP Equations and Exact Solutions 被引量:1
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作者 BAICheng-Jie BAICheng-Lin +1 位作者 HANJi-Guang ZHAOHong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4期677-680,共4页
By the application of the extended homogeneous balance method, we derive anauto-Backlund transformation (BT) for (2+1)-dimensional variable coefficient generalized KPequations. Based on the BT, in which there are two ... By the application of the extended homogeneous balance method, we derive anauto-Backlund transformation (BT) for (2+1)-dimensional variable coefficient generalized KPequations. Based on the BT, in which there are two homogeneity equations to be solved, we obtainsome exact solutions containing single solitary waves. 展开更多
关键词 extended homogeneous balance method (2+1)-dimensional variable coefficientgeneralized KP equation auto-Baecklund transformation exact solutions
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New Explicit Exact Solutions to (2+1)-Dimensional Generalized Broer-Kaup System
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作者 HUANGDing-Jiang ZHANGHong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3期397-400,共4页
A nonlinear transformation and some multi-solition solutions for the (2+1 )-dimensional generalized Broer-Kaup (GBK) system is first given by using the homogeneous balance method. Then starting from the nonlinear tran... A nonlinear transformation and some multi-solition solutions for the (2+1 )-dimensional generalized Broer-Kaup (GBK) system is first given by using the homogeneous balance method. Then starting from the nonlinear transformation, we reduce the (2+ 1)-dimensional GBK system to a simple linear evolution equation. Solving this equation,we can obtain some new explicit exact solutions of the original equations by means of the extended hyperbola function method. 展开更多
关键词 generalized Broer-Kaup system nonlinear transformation exact solutions homogeneous balance method hyperbola function method
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Exact Soliton Solutions to a Generalized Nonlinear Schrdinger Equation
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作者 徐四六 梁检初 易林 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第1期159-165,共7页
The (1+1)-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general (3+1)-dimensional nonlinear Schr6dinger equa... The (1+1)-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general (3+1)-dimensional nonlinear Schr6dinger equation (NLSE) with varying coefficients and a harmonica potential. We found that there exist two kinds of soliton solutions. The evolution features of exact solutions have been numerically studied. The (3+1)D soliton solutions may help us to understand the nonlinear wave propagation in the nonlinear media such as classical optical waves and the matter waves of the Bose-Einstein condensates. 展开更多
关键词 SELF-SIMILARITY nonlinear SchrSdinger equation exact soliton solutions
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New Exact Solutions and Dynamics in(3+1)-Dimensional Gross–Pitaevskii Equation with Repulsive Harmonic Potential 被引量:1
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作者 王晓丽 武振华 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第5期583-589,共7页
Using an improved homogeneous balance principle and an F-expansion technique, we construct the new exact periodic traveling wave solutions to the(3+1)-dimensional Gross–Pitaevskii equation with repulsive harmonic pot... Using an improved homogeneous balance principle and an F-expansion technique, we construct the new exact periodic traveling wave solutions to the(3+1)-dimensional Gross–Pitaevskii equation with repulsive harmonic potential. In the limit cases, the solitary wave solutions are obtained as well. We also investigate the dynamical evolution of the solitons with a time-dependent complicated potential. 展开更多
关键词 Gross-Pitaevskii equation exact solution solitory wave periodic wave F-expansion
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Exact Solutions of the Equilibrium Shape Equations in a General WLC Model for DNA Forms
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作者 Morteza Yavari 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第1期125-130,共6页
In this letter,we are going to use a geometrical approach to describe the free energy of DNA structures.The exact solutions of the equilibrium shape equations in a general WLC model for DNA forms by using the Feoli... In this letter,we are going to use a geometrical approach to describe the free energy of DNA structures.The exact solutions of the equilibrium shape equations in a general WLC model for DNA forms by using the Feoli's formalism [A.Feoli,et al.,Nucl.Phys.B 705(2005) 577] are studied.Then,the free energy of transition between Band Z-DNA is calculated in this formalism. 展开更多
关键词 equilibrium shape equation general WLC model Feoli's formalism B- to Z-DNA transition
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Exact Solitary Wave Solutions of Nonlinear Evolution Equations with a Positive Fractional Power Term 被引量:3
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作者 王明亮 李灵晓 李二强 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第1期7-14,共8页
The bounded and smooth solitary wave solutions of 10 nonlinear evolution equations with a positive fractional power term of dependent variable are successfully obtained by homogeneous balance principle and with the ai... The bounded and smooth solitary wave solutions of 10 nonlinear evolution equations with a positive fractional power term of dependent variable are successfully obtained by homogeneous balance principle and with the aid of sub-ODEs that admits a solution of sech-power or tanh-power type.In the special cases that the fractional power equals to 1 and 2,the solitary wave solutions of more than 10 important model equations arisen from mathematical physics are easily rediscovered. 展开更多
关键词 PDEs with fractional power term of dependent variable exact solitary wave solutions homogeneous balance principle sub-ODE which admits a solution of sech-power or tanhopower type
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