This paper presents a contribution related to the control of nonlinear variable-speed marine current turbine(MCT)without pitch operating below the rated marine current speed.Given that the operation of the MCT can be ...This paper presents a contribution related to the control of nonlinear variable-speed marine current turbine(MCT)without pitch operating below the rated marine current speed.Given that the operation of the MCT can be divided into several operating zones on the basis of the marine current speed,the system control objectives are different for each zone.To deal with this issue,we develop a new control approach based on a linear quadratic regulator with variable generator torque.Our proposed approach enables the optimization of the rotational speed of the turbine,which maximizes the power extracted by the MCT and minimizes the transient loads on the drivetrain.The novelty of our study is the use of a real profile of marine current speed from the northern coasts of Morocco.The simulation results obtained using MATLAB Simulink indicate the effectiveness and robustness of the proposed control approach on the electrical and mechanical parameters with the variations of marine current speed.展开更多
This paper describes an improvement of the existing nominal characteristic trajectory following (NCTF) as a practical control method for a two-mass rotary point-to-point (PTP) positioning systems. Generally, the NCTF ...This paper describes an improvement of the existing nominal characteristic trajectory following (NCTF) as a practical control method for a two-mass rotary point-to-point (PTP) positioning systems. Generally, the NCTF controller consists of a nominal characteristic trajectory (NCT) and a PI compensator. A notch filter is added as a part of the compensator to eliminate the vibration due to the mechanical resonance of the plant. The objective of the NCTF controller is to make the object motion follow the NCT and end at its origin. The NCTF controller is designed based on a simple open-loop experiment of the object. The parameters identification and an exact model of the plant are not necessary for controller design. The performance response of improved NCTF controller is evaluated and discussed based on results of simulation. The effect of the design parameters on the robustness of the NCTF controller to inertia and friction variations is evaluated and compared with conventional PID controller. The results show that the improved NCTF controller has a better positioning performance and is much more robust than the PID controller.展开更多
采用顶空固相微萃取结合全二维气相色谱-质谱(Headspace solid-phase microextraction-comprehensive two dimensional gas chromatography/mass spectrometry HS-SPME-GC×GC-MS)技术,对4种保健黄酒(黄精酒、黄米酒、藜麦酒和苦荞...采用顶空固相微萃取结合全二维气相色谱-质谱(Headspace solid-phase microextraction-comprehensive two dimensional gas chromatography/mass spectrometry HS-SPME-GC×GC-MS)技术,对4种保健黄酒(黄精酒、黄米酒、藜麦酒和苦荞酒)中挥发性物质的种类、含量分进行分析,并且通过主成分分析法很好地区分不同原料的保健黄酒,找出重要的组分差异特征,探究其风味成分。结果表明,GC×GC-MS检测到4种保健黄酒中挥发性组分156种,选取匹配度大于800的挥发性组分,4种保健黄酒中共鉴定出140种挥发性组分,其中包括酯类、醇类、醛酮类、酸类、烃类、含氮化合物、苯系芳烃及其它化合物等。该方法可以通过鉴定黄酒挥发性组分,寻找挥发性组分与黄酒品质之间的关系,为保健黄酒的生产优化提供一定的理论依据。展开更多
文摘This paper presents a contribution related to the control of nonlinear variable-speed marine current turbine(MCT)without pitch operating below the rated marine current speed.Given that the operation of the MCT can be divided into several operating zones on the basis of the marine current speed,the system control objectives are different for each zone.To deal with this issue,we develop a new control approach based on a linear quadratic regulator with variable generator torque.Our proposed approach enables the optimization of the rotational speed of the turbine,which maximizes the power extracted by the MCT and minimizes the transient loads on the drivetrain.The novelty of our study is the use of a real profile of marine current speed from the northern coasts of Morocco.The simulation results obtained using MATLAB Simulink indicate the effectiveness and robustness of the proposed control approach on the electrical and mechanical parameters with the variations of marine current speed.
文摘This paper describes an improvement of the existing nominal characteristic trajectory following (NCTF) as a practical control method for a two-mass rotary point-to-point (PTP) positioning systems. Generally, the NCTF controller consists of a nominal characteristic trajectory (NCT) and a PI compensator. A notch filter is added as a part of the compensator to eliminate the vibration due to the mechanical resonance of the plant. The objective of the NCTF controller is to make the object motion follow the NCT and end at its origin. The NCTF controller is designed based on a simple open-loop experiment of the object. The parameters identification and an exact model of the plant are not necessary for controller design. The performance response of improved NCTF controller is evaluated and discussed based on results of simulation. The effect of the design parameters on the robustness of the NCTF controller to inertia and friction variations is evaluated and compared with conventional PID controller. The results show that the improved NCTF controller has a better positioning performance and is much more robust than the PID controller.
文摘采用顶空固相微萃取结合全二维气相色谱-质谱(Headspace solid-phase microextraction-comprehensive two dimensional gas chromatography/mass spectrometry HS-SPME-GC×GC-MS)技术,对4种保健黄酒(黄精酒、黄米酒、藜麦酒和苦荞酒)中挥发性物质的种类、含量分进行分析,并且通过主成分分析法很好地区分不同原料的保健黄酒,找出重要的组分差异特征,探究其风味成分。结果表明,GC×GC-MS检测到4种保健黄酒中挥发性组分156种,选取匹配度大于800的挥发性组分,4种保健黄酒中共鉴定出140种挥发性组分,其中包括酯类、醇类、醛酮类、酸类、烃类、含氮化合物、苯系芳烃及其它化合物等。该方法可以通过鉴定黄酒挥发性组分,寻找挥发性组分与黄酒品质之间的关系,为保健黄酒的生产优化提供一定的理论依据。
