混合型统一潮流控制器(hybrid unified power flow controller,HUPFC)可以实现统一潮流控制器(unified power flow controller,UPFC)与移相变压器('Sen'transformer,ST)的优势互补,广泛应用于系统潮流控制之中.但是,尚未有文献...混合型统一潮流控制器(hybrid unified power flow controller,HUPFC)可以实现统一潮流控制器(unified power flow controller,UPFC)与移相变压器('Sen'transformer,ST)的优势互补,广泛应用于系统潮流控制之中.但是,尚未有文献开展HUPFC抑制系统次同步振荡(sub-synchronous oscillation,SSO)的研究.针对双馈风机(double-fed induction generator,DFIG)经串补输电系统存在的SSO问题,提出一种HUPFC附加有源电阻控制(supplementary active resistance control,SARC)策略.首先,阐述了HUPFC的原理及其SSO抑制机理.然后,设计了SARC策略,该策略通过实时跟踪线路中的次同步电流信号,使HUPFC向输电线路叠加一个与次同步电流信号相位相同、幅值可变的次同步电压,进而实现系统等效正电阻,达到抑制SSO的目的.最后,给出了SARC的参数设计方法,在PSCAD/EMTDC仿真环境中,以华北某风电场为仿真算例,采用频率扫描与时域仿真相结合的方法,验证了所提HUPFC的SARC策略抑制双馈风机经串补输电系统SSO的有效性.展开更多
This paper explores the conceptual basis of finite complementation in English. It first considers the distinguishing property of a finite clause,namely grounding,effected by tense and the modals. Notions crucial for c...This paper explores the conceptual basis of finite complementation in English. It first considers the distinguishing property of a finite clause,namely grounding,effected by tense and the modals. Notions crucial for clausal grounding—including a reality conception and the striving for control at the effective and epistemic levels—also figure in the semantic import of complementation. An essential feature of complement constructions is the involvement of multiple conceptualizers,each with their own conception of reality. The different types of complement and their grammatical markings can be characterized on this basis. Finite complements differ from other types by virtue of expressing an autonomous proposition capable of being apprehended by multiple conceptualizers,each from their own vantage point. A cognitive model representing phases in the striving for epistemic control provides a partial basis for the semantic description of predicates taking finite complements. The same model supports the description of both personal and impersonal complement constructions.展开更多
This paper presents a simultaneous H2/H∞ stabilization problem for the chemical reaction systems which can be modeled as a finite collection of subsystems. A single dynamic output feedback controller which simultaneo...This paper presents a simultaneous H2/H∞ stabilization problem for the chemical reaction systems which can be modeled as a finite collection of subsystems. A single dynamic output feedback controller which simultaneously stabilizes the multiple subsystems and captures the mixed H2/H∞ control performance is designed. To ensure that the stability condition, the H2 characterization and the H∞ characterization can be enforced within a unified matrix inequality framework, a novel technique based on orthogonal complement space is developed. Within such a framework, the controller gain is parameterized by the introduction of a common free positive definite matrix, which is independent of the multiple Lyapunov matrices. An iterative linear matrix inequality （ILMI） algorithm using Matlab Yalmip toolbox is established to deal with the proposed framework. Simulation results of a typical chemical reaction system are exploited to show the validity of the proposed methodology.展开更多
文摘混合型统一潮流控制器(hybrid unified power flow controller,HUPFC)可以实现统一潮流控制器(unified power flow controller,UPFC)与移相变压器('Sen'transformer,ST)的优势互补,广泛应用于系统潮流控制之中.但是,尚未有文献开展HUPFC抑制系统次同步振荡(sub-synchronous oscillation,SSO)的研究.针对双馈风机(double-fed induction generator,DFIG)经串补输电系统存在的SSO问题,提出一种HUPFC附加有源电阻控制(supplementary active resistance control,SARC)策略.首先,阐述了HUPFC的原理及其SSO抑制机理.然后,设计了SARC策略,该策略通过实时跟踪线路中的次同步电流信号,使HUPFC向输电线路叠加一个与次同步电流信号相位相同、幅值可变的次同步电压,进而实现系统等效正电阻,达到抑制SSO的目的.最后,给出了SARC的参数设计方法,在PSCAD/EMTDC仿真环境中,以华北某风电场为仿真算例,采用频率扫描与时域仿真相结合的方法,验证了所提HUPFC的SARC策略抑制双馈风机经串补输电系统SSO的有效性.
文摘This paper explores the conceptual basis of finite complementation in English. It first considers the distinguishing property of a finite clause,namely grounding,effected by tense and the modals. Notions crucial for clausal grounding—including a reality conception and the striving for control at the effective and epistemic levels—also figure in the semantic import of complementation. An essential feature of complement constructions is the involvement of multiple conceptualizers,each with their own conception of reality. The different types of complement and their grammatical markings can be characterized on this basis. Finite complements differ from other types by virtue of expressing an autonomous proposition capable of being apprehended by multiple conceptualizers,each from their own vantage point. A cognitive model representing phases in the striving for epistemic control provides a partial basis for the semantic description of predicates taking finite complements. The same model supports the description of both personal and impersonal complement constructions.
基金supported by National Natural Science Foundation of China(No.61174064)National Basic Research Program of China(973 Program)(No.2012CB720502)
文摘This paper presents a simultaneous H2/H∞ stabilization problem for the chemical reaction systems which can be modeled as a finite collection of subsystems. A single dynamic output feedback controller which simultaneously stabilizes the multiple subsystems and captures the mixed H2/H∞ control performance is designed. To ensure that the stability condition, the H2 characterization and the H∞ characterization can be enforced within a unified matrix inequality framework, a novel technique based on orthogonal complement space is developed. Within such a framework, the controller gain is parameterized by the introduction of a common free positive definite matrix, which is independent of the multiple Lyapunov matrices. An iterative linear matrix inequality （ILMI） algorithm using Matlab Yalmip toolbox is established to deal with the proposed framework. Simulation results of a typical chemical reaction system are exploited to show the validity of the proposed methodology.
