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
Nonylphenol(NP), nonylphenoxy acetic acid(NP1EC), nonylphenol monoethoxy acetic acid(NP2EC), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) are biodegradation end products(BEPs) of nonionic surf...Nonylphenol(NP), nonylphenoxy acetic acid(NP1EC), nonylphenol monoethoxy acetic acid(NP2EC), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) are biodegradation end products(BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NPnEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4 h. In sorption isotherm experiments, obtained equilibrium data at 28℃ fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient(K F) and linear sorption coefficient(K D) showed that sorption capacity of the investigated compounds were in order NP>NP2EO>NP1EO>NP1EC≈NP2EC. For NP, NP1EO and NP2EO, high values of calculated K F and K D indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with low values of K F and K D absorbed weakly to activated sludge and tended to preferably remain in aqueous phase.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
To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficien...To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al_2O_3-SiO_2 slag. The activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag both show a positive deviation from Raoult＇s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B =（%CaO）/（%SiO_2） = 1, where B is the basicity. We observed that controlling the slag composition at approximately B = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.展开更多
Although previous studies on Korean manufacturing firms have empirically analyzed the causal relationship between activities during the FFE(Fuzzy Front End)and success of NPD(New Product Development)of Korean manufact...Although previous studies on Korean manufacturing firms have empirically analyzed the causal relationship between activities during the FFE(Fuzzy Front End)and success of NPD(New Product Development)of Korean manufacturing firms,no study has concretely focused on Korean ICT(Information and Communications Technology)firms and their FFE activities.The main aim of this study is to identify the activities of these firms during their FFE and provide managerial insights into the other ICT firms.The authors conducted a survey(106 valid responses)that their FFE activities on new product development project managers in Korean ICT firms.The results showed that even though new product development managers of Korean ICT firms did not search for ideas systemically,they communicated with those departments/divisions that had frequent interaction with customers for idea assessment,with the active involvement of middle-or higher-level managers.They thoroughly established initial plans in the pre-development stages and seriously analyzed competitors’products and direct and indirect customer interactions in their market survey activities.展开更多
In order to improve the yaw stability of the vehicle with active front steering system, an adaptive PID-type fuzzy control scheme is designed to make the yaw rate tracking the desired values as close as possible. A 2-...In order to improve the yaw stability of the vehicle with active front steering system, an adaptive PID-type fuzzy control scheme is designed to make the yaw rate tracking the desired values as close as possible. A 2-DOF vehicle model with active front steering is built firstly, and then the fuzzy PID controller is designed in detail. The simulation investigations of the yaw stability with different steering ma- neuvers are performed. The simulation results show the effectiveness of the fuzzy PID controller for improving the vehicle＇s yaw stability.展开更多
This paper discusses a novel boost single-phase active AC-DC converters, named low-end semi-controlled bridge AC-DC converter. By analysis, its topology and principle can be derived from the conventional single-phase ...This paper discusses a novel boost single-phase active AC-DC converters, named low-end semi-controlled bridge AC-DC converter. By analysis, its topology and principle can be derived from the conventional single-phase power factor corrector （ PFC）. But it has also some differences, such as power device positions, inductor type, input voltage waveform detection and induction current detection, so its design is also different. The converter is implemented by employing two current detection approaches, i.e., current transformer detection and shunt resistor detection. Consequently, it can provide a steady DC output voltage with a low voltage ripple, approximately unitary input power factor and 2.5 kW output power. The experimental results show validity of the theoretical analysis.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
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Nonylphenol(NP), nonylphenoxy acetic acid(NP1EC), nonylphenol monoethoxy acetic acid(NP2EC), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) are biodegradation end products(BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NPnEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4 h. In sorption isotherm experiments, obtained equilibrium data at 28℃ fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient(K F) and linear sorption coefficient(K D) showed that sorption capacity of the investigated compounds were in order NP>NP2EO>NP1EO>NP1EC≈NP2EC. For NP, NP1EO and NP2EO, high values of calculated K F and K D indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with low values of K F and K D absorbed weakly to activated sludge and tended to preferably remain in aqueous phase.
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。
基金the support of a scholarship provided by the Japan Society for the Promotion of Science(No. H26-3293)the scholarship provided by the Ministry of Education,Culture,Sports,Science and Technology,Japan(Registered number: 123032) during his doctor course
文摘To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al_2O_3-SiO_2 slag. The activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag both show a positive deviation from Raoult＇s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B =（%CaO）/（%SiO_2） = 1, where B is the basicity. We observed that controlling the slag composition at approximately B = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.
文摘Although previous studies on Korean manufacturing firms have empirically analyzed the causal relationship between activities during the FFE(Fuzzy Front End)and success of NPD(New Product Development)of Korean manufacturing firms,no study has concretely focused on Korean ICT(Information and Communications Technology)firms and their FFE activities.The main aim of this study is to identify the activities of these firms during their FFE and provide managerial insights into the other ICT firms.The authors conducted a survey(106 valid responses)that their FFE activities on new product development project managers in Korean ICT firms.The results showed that even though new product development managers of Korean ICT firms did not search for ideas systemically,they communicated with those departments/divisions that had frequent interaction with customers for idea assessment,with the active involvement of middle-or higher-level managers.They thoroughly established initial plans in the pre-development stages and seriously analyzed competitors’products and direct and indirect customer interactions in their market survey activities.
基金Supported by the National Natural Science Foundation of China （No.50705008）
文摘In order to improve the yaw stability of the vehicle with active front steering system, an adaptive PID-type fuzzy control scheme is designed to make the yaw rate tracking the desired values as close as possible. A 2-DOF vehicle model with active front steering is built firstly, and then the fuzzy PID controller is designed in detail. The simulation investigations of the yaw stability with different steering ma- neuvers are performed. The simulation results show the effectiveness of the fuzzy PID controller for improving the vehicle＇s yaw stability.
文摘This paper discusses a novel boost single-phase active AC-DC converters, named low-end semi-controlled bridge AC-DC converter. By analysis, its topology and principle can be derived from the conventional single-phase power factor corrector （ PFC）. But it has also some differences, such as power device positions, inductor type, input voltage waveform detection and induction current detection, so its design is also different. The converter is implemented by employing two current detection approaches, i.e., current transformer detection and shunt resistor detection. Consequently, it can provide a steady DC output voltage with a low voltage ripple, approximately unitary input power factor and 2.5 kW output power. The experimental results show validity of the theoretical analysis.
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.
