为有效改善船舶电力推进系统电能质量和能量反馈,将有源前端(Active Front End,AFE)变频器应用于船舶电力推进电机控制.根据船舶电力推进系统的特点,选择基于电流内环前馈解耦控制的直接电流控制方法,并对AFE变频器的独立控制和联合控...为有效改善船舶电力推进系统电能质量和能量反馈,将有源前端(Active Front End,AFE)变频器应用于船舶电力推进电机控制.根据船舶电力推进系统的特点,选择基于电流内环前馈解耦控制的直接电流控制方法,并对AFE变频器的独立控制和联合控制方式进行研究.用MATLAB/Simulink对这两种方式进行仿真.分析仿真结果,得出这两种控制方式分别适应的电力推进船舶类型.展开更多
为了减小用电设备对电网的谐波污染和提高自身的功率因数,AFE的应用越来越广泛。研究及分析了有源前端AFE(active front end)的工作原理、数学模型、电压和电流的闭环控制策略,给出了主电路的结构和主要参数的设计方法。通过仿真分析了...为了减小用电设备对电网的谐波污染和提高自身的功率因数,AFE的应用越来越广泛。研究及分析了有源前端AFE(active front end)的工作原理、数学模型、电压和电流的闭环控制策略,给出了主电路的结构和主要参数的设计方法。通过仿真分析了控制方案的可行性,并列举了在工程上的应用。应用实例表明,AFE有良好的动态性能,在工业现场运行安全可靠。展开更多
An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated...An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation （HILS） system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.展开更多
针对有源前端AFE(active front-end)变换器电流环采用的有限控制集模型预测控制算法FCS-MPC(finite control set model predictive control),存在数字控制器计算量大、输出的电流脉动大和系统性能差等问题,提出了一种改进模型预测控制...针对有源前端AFE(active front-end)变换器电流环采用的有限控制集模型预测控制算法FCS-MPC(finite control set model predictive control),存在数字控制器计算量大、输出的电流脉动大和系统性能差等问题,提出了一种改进模型预测控制策略。首先通过坐标变换构建α-β坐标下AFE变换器的预测模型;结合电压型空间矢量变换的原理,引入矢量扇区判断法,减少最优电压矢量选择的次数;最后根据选出来的电压矢量,在1个控制周期内同时施加有效电压矢量和零电压矢量,并分配相应的作用时间。该方法不但保留了传统MPC算法的快速动态响应特性,而且改善了系统的稳态性能。仿真和实验结果均验证了所提方法的正确性与有效性。展开更多
本文侧重于主动前轮转向(Active Front Steering,AFS)控制系统的应用性与可行性研究,针对紧急转向工况下轮胎呈现强非线性问题,以及AFS控制算法中部分状态量难以获取、路面附着系数对车辆稳定性有重要影响但难以直接测量等问题,设计非...本文侧重于主动前轮转向(Active Front Steering,AFS)控制系统的应用性与可行性研究,针对紧急转向工况下轮胎呈现强非线性问题,以及AFS控制算法中部分状态量难以获取、路面附着系数对车辆稳定性有重要影响但难以直接测量等问题,设计非线性滑模控制器以综合考虑载荷转移、轮胎非线性及路面条件等对操稳性影响,同时,通过ESP系统现有的IMU传感器测量信息,运用无迹卡尔曼滤波(Unscented Kalman Filter,UKF)算法为滑模控制器动态估计车辆状态信息和路面附着系数.在得到期望轮胎侧偏力后,通过非线性轮胎模型精确反求所需叠加转角,以在“轮胎-路面”附着能力范围内检验控制系统的有效性.最后,高附着系数情况下的鱼钩测试仿真及低附着系数时的角阶跃转向仿真共同表明,通过IMU与UKF结合的状态估计确保了AFS控制系统的可行性,有效提高了车辆操纵稳定性.展开更多
提出了一种基于模型预测电流控制(model predictive current control,MPCC)的具有有源滤波功能的光伏并网(photovoltaic power generation and active filter,PV-AF)系统控制策略。电流环采用模型预测控制(model predictive control,MPC...提出了一种基于模型预测电流控制(model predictive current control,MPCC)的具有有源滤波功能的光伏并网(photovoltaic power generation and active filter,PV-AF)系统控制策略。电流环采用模型预测控制(model predictive control,MPC)方法,在???坐标系下实现对光伏逆变电流指令和谐波补偿电流指令的无静差跟踪,使PV-AF系统将光伏阵列的能量注入交流电网的同时,有效补偿本地并联负载谐波电流。建立了MPC中的预测模型、优化函数等,分析了模型参数对系统稳定性和控制精度的影响。实验结果验证了所提策略的有效性。展开更多
To investigate the influence of preparation process on the properties of synthesized C4AF,the powder was prepared via the self-propagating combustion reaction（SPCR）method using urea as fuel and metal nitrates as cat...To investigate the influence of preparation process on the properties of synthesized C4AF,the powder was prepared via the self-propagating combustion reaction（SPCR）method using urea as fuel and metal nitrates as cation precursors.Synthesis mechanism of the SPCR method,calculation and adjusting principles of urea dosage were detailedly introduced.Material characterization of synthesized C4AF was performed with the aid of X-ray diffractometry,Fourier transform infrared spectrometry,scanning electron microscopy,energydispersive X-ray spectroscopy,^27Al nuclear magnetic resonance and isothermal microcalorimetric technique.Remaining content of transition phase of calcium carbonate in synthesized C4AF was determined by quantitative analysis of X-ray diffractometry.It was found that there was no difference in the hydration behavior of C4AF synthesized by the SPCR method and the traditional solid-state reaction（SSR）method.C3AH6 and amorphous iron（III）hydroxide（Fe（OH）3）would be formed during the hydration of C4AF while CH not.Crystallite size of synthesized C4AF was 16.1 A and the apparent activation energy was 36.2 kJ/mol.Coordinated condition of Al in C4AF can be detected by ^27Al NMR technique,but the peaks were broadened and the intensities were relatively low,supporting the use of ^27Al NMR for the quantitative analysis of C3A in Portland cements.展开更多
文摘为有效改善船舶电力推进系统电能质量和能量反馈,将有源前端(Active Front End,AFE)变频器应用于船舶电力推进电机控制.根据船舶电力推进系统的特点,选择基于电流内环前馈解耦控制的直接电流控制方法,并对AFE变频器的独立控制和联合控制方式进行研究.用MATLAB/Simulink对这两种方式进行仿真.分析仿真结果,得出这两种控制方式分别适应的电力推进船舶类型.
文摘为了减小用电设备对电网的谐波污染和提高自身的功率因数,AFE的应用越来越广泛。研究及分析了有源前端AFE(active front end)的工作原理、数学模型、电压和电流的闭环控制策略,给出了主电路的结构和主要参数的设计方法。通过仿真分析了控制方案的可行性,并列举了在工程上的应用。应用实例表明,AFE有良好的动态性能,在工业现场运行安全可靠。
文摘An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation （HILS） system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.
文摘针对有源前端AFE(active front-end)变换器电流环采用的有限控制集模型预测控制算法FCS-MPC(finite control set model predictive control),存在数字控制器计算量大、输出的电流脉动大和系统性能差等问题,提出了一种改进模型预测控制策略。首先通过坐标变换构建α-β坐标下AFE变换器的预测模型;结合电压型空间矢量变换的原理,引入矢量扇区判断法,减少最优电压矢量选择的次数;最后根据选出来的电压矢量,在1个控制周期内同时施加有效电压矢量和零电压矢量,并分配相应的作用时间。该方法不但保留了传统MPC算法的快速动态响应特性,而且改善了系统的稳态性能。仿真和实验结果均验证了所提方法的正确性与有效性。
文摘本文侧重于主动前轮转向(Active Front Steering,AFS)控制系统的应用性与可行性研究,针对紧急转向工况下轮胎呈现强非线性问题,以及AFS控制算法中部分状态量难以获取、路面附着系数对车辆稳定性有重要影响但难以直接测量等问题,设计非线性滑模控制器以综合考虑载荷转移、轮胎非线性及路面条件等对操稳性影响,同时,通过ESP系统现有的IMU传感器测量信息,运用无迹卡尔曼滤波(Unscented Kalman Filter,UKF)算法为滑模控制器动态估计车辆状态信息和路面附着系数.在得到期望轮胎侧偏力后,通过非线性轮胎模型精确反求所需叠加转角,以在“轮胎-路面”附着能力范围内检验控制系统的有效性.最后,高附着系数情况下的鱼钩测试仿真及低附着系数时的角阶跃转向仿真共同表明,通过IMU与UKF结合的状态估计确保了AFS控制系统的可行性,有效提高了车辆操纵稳定性.
文摘提出了一种基于模型预测电流控制(model predictive current control,MPCC)的具有有源滤波功能的光伏并网(photovoltaic power generation and active filter,PV-AF)系统控制策略。电流环采用模型预测控制(model predictive control,MPC)方法,在???坐标系下实现对光伏逆变电流指令和谐波补偿电流指令的无静差跟踪,使PV-AF系统将光伏阵列的能量注入交流电网的同时,有效补偿本地并联负载谐波电流。建立了MPC中的预测模型、优化函数等,分析了模型参数对系统稳定性和控制精度的影响。实验结果验证了所提策略的有效性。
基金Funded partly by the National“973”Program of China(No.2015CB655101)National Natural Science Foundation of China(No.51379163)
文摘To investigate the influence of preparation process on the properties of synthesized C4AF,the powder was prepared via the self-propagating combustion reaction（SPCR）method using urea as fuel and metal nitrates as cation precursors.Synthesis mechanism of the SPCR method,calculation and adjusting principles of urea dosage were detailedly introduced.Material characterization of synthesized C4AF was performed with the aid of X-ray diffractometry,Fourier transform infrared spectrometry,scanning electron microscopy,energydispersive X-ray spectroscopy,^27Al nuclear magnetic resonance and isothermal microcalorimetric technique.Remaining content of transition phase of calcium carbonate in synthesized C4AF was determined by quantitative analysis of X-ray diffractometry.It was found that there was no difference in the hydration behavior of C4AF synthesized by the SPCR method and the traditional solid-state reaction（SSR）method.C3AH6 and amorphous iron（III）hydroxide（Fe（OH）3）would be formed during the hydration of C4AF while CH not.Crystallite size of synthesized C4AF was 16.1 A and the apparent activation energy was 36.2 kJ/mol.Coordinated condition of Al in C4AF can be detected by ^27Al NMR technique,but the peaks were broadened and the intensities were relatively low,supporting the use of ^27Al NMR for the quantitative analysis of C3A in Portland cements.
