In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the outpu...In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the output becomes unstable because of intermittent characteristics, such as variations of wind speed or solar radiation intensity. Frequency fluctuations due to the installation of large scale wind farm (WF) and photovoltaics (PV) into the power system is a major concern. In order to solve the problem, this paper proposes two control methods using High Voltage Direct Current (HVDC) interconnection line to suppress the frequency fluctuations due to large scale of WF and PV. Comparative analysis between these two control methods is presented in this paper. One proposed method is a frequency control using a notch filter, and the other is using a deadband. Validity of the proposed methods is verified through simulation analyses, which is performed on a multi-machine power system model.展开更多
Heart state information and neural control expounded by multiple parameters are useful for early diagnosis of heart diseases. The purpose of this article is to investigate the effectiveness of multiple parameters for ...Heart state information and neural control expounded by multiple parameters are useful for early diagnosis of heart diseases. The purpose of this article is to investigate the effectiveness of multiple parameters for express heart state variation and neural control. We have studied three kinds of parameters global, local and dynamic ones with different confirmation method to extract concealed physiological and pathological heart information with animal models. Pathological notch on QRS complex of electrocardiogram (ECG) is defined as a local parameter which is one of the high frequency components (HFCs). The poincare dispersed dot plot (PDDP) is defined as a nonlinear global parameter. Pathological notching information on the QRS complex is related to myocardial injuries. We have been working on man made myocardial infarction models to simulate cardiac abnormalities. Thirty eight percent (38%) formalin was used to produce acute myocardial injury and several branches of coronary anterior descending branch near apex and part of blunt edge branch were ligatured for creating chronic pathological changes in order to form small injurious areas at left ventricular side wall. And we found that both myocardial injury approaches could produce good idiosyncratic relationship between injury area model and man made pathological condition. A large number of repetitive experiments of animal model indicated that the thresholds of pathological notching are about 84 μV in amplitude and 3.8 ms in width. The PDDP was a good parameter of heart nonlinear state and heart rate variability (HRV). It has thresholds of about 26000 ms 2 in area and 420 ms in long axis for human being and 600 ms 2 in area and 85 ms in long axis for dogs. Both parameters exhibit sensitive and early response to heart states pathological variation and also have dynamic characteristics.展开更多
传统高频脉振电压注入法采用基于带通滤波器与低通滤波器结合的策略,实现位置误差信号提取。但该策略的不足在于无法同时兼顾位置观测闭环的滤波精度与动态性能。为此,提出一种基于双频陷波器(dual frequency notch filter,DFNF)级联低...传统高频脉振电压注入法采用基于带通滤波器与低通滤波器结合的策略,实现位置误差信号提取。但该策略的不足在于无法同时兼顾位置观测闭环的滤波精度与动态性能。为此,提出一种基于双频陷波器(dual frequency notch filter,DFNF)级联低通滤波器的改进型位置误差信号提取策略。该策略通过提高环路增益实现带宽扩展,再利用DFNF加强对二次注入谐波的抑制能力,使位置观测环同时具备高带宽与强滤波特性。首先,对位置观测等效闭环进行建模,并利用闭环传递函数幅频特性分析传统位置误差信号提取策略存在的问题;然后,对改进型位置误差信号提取策略的原理进行介绍,并对比2种位置误差信号提取策略的性能;最后,基于RT-LAB实验平台,对2种位置误差信号提取策略的位置辨识效果进行对比验证。展开更多
文摘In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the output becomes unstable because of intermittent characteristics, such as variations of wind speed or solar radiation intensity. Frequency fluctuations due to the installation of large scale wind farm (WF) and photovoltaics (PV) into the power system is a major concern. In order to solve the problem, this paper proposes two control methods using High Voltage Direct Current (HVDC) interconnection line to suppress the frequency fluctuations due to large scale of WF and PV. Comparative analysis between these two control methods is presented in this paper. One proposed method is a frequency control using a notch filter, and the other is using a deadband. Validity of the proposed methods is verified through simulation analyses, which is performed on a multi-machine power system model.
基金The Project is sponsored in part by National Natural Science Foundation of China ( 3 9970 2 0 53 92 70 1843 870 613 )
文摘Heart state information and neural control expounded by multiple parameters are useful for early diagnosis of heart diseases. The purpose of this article is to investigate the effectiveness of multiple parameters for express heart state variation and neural control. We have studied three kinds of parameters global, local and dynamic ones with different confirmation method to extract concealed physiological and pathological heart information with animal models. Pathological notch on QRS complex of electrocardiogram (ECG) is defined as a local parameter which is one of the high frequency components (HFCs). The poincare dispersed dot plot (PDDP) is defined as a nonlinear global parameter. Pathological notching information on the QRS complex is related to myocardial injuries. We have been working on man made myocardial infarction models to simulate cardiac abnormalities. Thirty eight percent (38%) formalin was used to produce acute myocardial injury and several branches of coronary anterior descending branch near apex and part of blunt edge branch were ligatured for creating chronic pathological changes in order to form small injurious areas at left ventricular side wall. And we found that both myocardial injury approaches could produce good idiosyncratic relationship between injury area model and man made pathological condition. A large number of repetitive experiments of animal model indicated that the thresholds of pathological notching are about 84 μV in amplitude and 3.8 ms in width. The PDDP was a good parameter of heart nonlinear state and heart rate variability (HRV). It has thresholds of about 26000 ms 2 in area and 420 ms in long axis for human being and 600 ms 2 in area and 85 ms in long axis for dogs. Both parameters exhibit sensitive and early response to heart states pathological variation and also have dynamic characteristics.
文摘传统高频脉振电压注入法采用基于带通滤波器与低通滤波器结合的策略,实现位置误差信号提取。但该策略的不足在于无法同时兼顾位置观测闭环的滤波精度与动态性能。为此,提出一种基于双频陷波器(dual frequency notch filter,DFNF)级联低通滤波器的改进型位置误差信号提取策略。该策略通过提高环路增益实现带宽扩展,再利用DFNF加强对二次注入谐波的抑制能力,使位置观测环同时具备高带宽与强滤波特性。首先,对位置观测等效闭环进行建模,并利用闭环传递函数幅频特性分析传统位置误差信号提取策略存在的问题;然后,对改进型位置误差信号提取策略的原理进行介绍,并对比2种位置误差信号提取策略的性能;最后,基于RT-LAB实验平台,对2种位置误差信号提取策略的位置辨识效果进行对比验证。
