The analysis and design of the extended state observer （ESO） involves a continuous non-smooth structure, thus the study of the ESO dynamic requires mathematical tools of the nonlinear systems analysis. This paper es...The analysis and design of the extended state observer （ESO） involves a continuous non-smooth structure, thus the study of the ESO dynamic requires mathematical tools of the nonlinear systems analysis. This paper establishes the sufficient conditions for absolute stability of the ESO. Based on this study, a methodology to estimate several nonlinear functions in dy- namics systems is proposed.展开更多
This paper concerns the absolute stability problem of discrete-time descriptor systems with feedback connected ferromagnetic hysteresis nonlinearities. The ferromagnetic hysteresis model satisfies the passivity condit...This paper concerns the absolute stability problem of discrete-time descriptor systems with feedback connected ferromagnetic hysteresis nonlinearities. The ferromagnetic hysteresis model satisfies the passivity conditions of hysteresis operator, that is the input-output relation of the transformed operator is passive. The bound condition of the solution of the ferromagnetic hysteresis model is given. Through the framework of loop transformation, an augmented discrete-time descriptor system model is established for the stability analysis. A new extended Tsypkin criterion for the absolute stability of discrete-time descriptor systems with hysteresis is presented based on the linear matrix inequalities technique. A numerical example is given to illustrate the effectiveness of the extended criterion.展开更多
多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺...多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺少相应的指标;现有研究也尚未解决如何利用EDCPS最大程度提升多直流综合送出能力的问题。应用扩展等面积法(extended equal area criterion,EEAC)定量分析了EDCPS提升多直流送端系统暂态稳定性的机理;以两送出直流系统为例,推导了基于EEAC的暂态稳定裕度η对EDCPS的灵敏度公式;在此基础上,提出一种在不增加相关设备投入的前提下利用系统中现有稳控措施并结合暂态稳定裕度灵敏度的多直流送出能力提升控制方法,通过计算备选直流的暂态稳定裕度灵敏度,可以完整反映系统在遭受大扰动后的动态特性以及定量评估EDCPS对系统受扰后稳定性的改善效果,避免过去仅凭运行人员经验选取支援直流的问题,提高计算效率;最后,选取西北电网实际算例对所提出的多直流送出能力提升控制方法有效性进行仿真验证,以期为从事交直流混联电力系统稳定性分析与控制的学者和工程师们提供有益的参考。展开更多
对于多直流的交直流混联系统,直流调制可作为区间低频振荡的一种有效抑制措施,同时直流调制器的安装地点选择也迎来了新的课题研究。提出了基于扩展等面积法则EEAC(extended equal area criterion)的低频振荡主导模式识别方法,并基于此...对于多直流的交直流混联系统,直流调制可作为区间低频振荡的一种有效抑制措施,同时直流调制器的安装地点选择也迎来了新的课题研究。提出了基于扩展等面积法则EEAC(extended equal area criterion)的低频振荡主导模式识别方法,并基于此给出一种简化的在线求取主导模式下的机组归一化参与因子方法;应用多直流控制敏感点识别策略,通过经验模态分解的普罗尼EMD-Prony(empirical mode decomposition-Prony)辨识各直流线整流侧和逆变侧瞬时冲击下的发电机加权功角曲线,得到各主导模式对应的各直流线整流侧和逆变侧的控制敏感因子,在各直流线的换流站加双侧频差直流调制,调制器的参数采用传递函数辨识和极点配置法相结合进行整定。算例仿真验证了所提方法的有效性。展开更多
基金supported by Programa de Jovenes Investigadores e Innovadores COLCIENCIAS (DFIA-0494)Universidad Nacional de Colombia Manizales (12475),Vicerrectoría de Investigación,DIMA.
文摘The analysis and design of the extended state observer （ESO） involves a continuous non-smooth structure, thus the study of the ESO dynamic requires mathematical tools of the nonlinear systems analysis. This paper establishes the sufficient conditions for absolute stability of the ESO. Based on this study, a methodology to estimate several nonlinear functions in dy- namics systems is proposed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50977008,60821063 and 61034005)National Basic Research Program of China (Grant No. 2009CB32060)
文摘This paper concerns the absolute stability problem of discrete-time descriptor systems with feedback connected ferromagnetic hysteresis nonlinearities. The ferromagnetic hysteresis model satisfies the passivity conditions of hysteresis operator, that is the input-output relation of the transformed operator is passive. The bound condition of the solution of the ferromagnetic hysteresis model is given. Through the framework of loop transformation, an augmented discrete-time descriptor system model is established for the stability analysis. A new extended Tsypkin criterion for the absolute stability of discrete-time descriptor systems with hysteresis is presented based on the linear matrix inequalities technique. A numerical example is given to illustrate the effectiveness of the extended criterion.
文摘多直流送端系统内某一直流线路发生闭锁故障后,可以通过对其他非故障直流进行紧急功率支援(emergency DC power support,EDCPS)控制来提升系统受扰后的稳定性。如何有效量化EDCPS对系统稳定性的改善效果,从而提高安稳控制的效率,目前缺少相应的指标;现有研究也尚未解决如何利用EDCPS最大程度提升多直流综合送出能力的问题。应用扩展等面积法(extended equal area criterion,EEAC)定量分析了EDCPS提升多直流送端系统暂态稳定性的机理;以两送出直流系统为例,推导了基于EEAC的暂态稳定裕度η对EDCPS的灵敏度公式;在此基础上,提出一种在不增加相关设备投入的前提下利用系统中现有稳控措施并结合暂态稳定裕度灵敏度的多直流送出能力提升控制方法,通过计算备选直流的暂态稳定裕度灵敏度,可以完整反映系统在遭受大扰动后的动态特性以及定量评估EDCPS对系统受扰后稳定性的改善效果,避免过去仅凭运行人员经验选取支援直流的问题,提高计算效率;最后,选取西北电网实际算例对所提出的多直流送出能力提升控制方法有效性进行仿真验证,以期为从事交直流混联电力系统稳定性分析与控制的学者和工程师们提供有益的参考。
