This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)c...This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.展开更多
An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead z...An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.展开更多
文摘This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.
基金Supported by the National Natural Science Foundation of China (No.10802024)Research Fund for the Doctoral Program of Higher Education of China (No. 200802171009)+1 种基金Innovative Talents Fund of Harbin (No.2009RFQXG211)Fundamental Research Fund of HEU (No. HEUFT08003)
文摘An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.
