In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)i...In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.展开更多
This paper concludes the case study work on the optical sensor, which is a new method for voltage and current measurement. Fiber Bragg gratings (FBG) have been developed and used for decades in the telecommunication i...This paper concludes the case study work on the optical sensor, which is a new method for voltage and current measurement. Fiber Bragg gratings (FBG) have been developed and used for decades in the telecommunication industry. In recent years, FBG sensors have found wide applications in monitoring strain, temperature, voltage and current across all industries. As the process of constructing a robust smart grid, thousands of miles of optical-fibers have been deployed along the power transmission lines for the purpose of power production communication. This paper focuses on using the power optical fiber as voltage/current sensors instead of those copper wired traditional current transformers. By using piezoelectric layers, the optical sensor is able to transform voltage/current magnitude into optical signal, as well as transmit the signal through the optical fiber. The application of using optical fiber will significantly reduce the cost of deploying traditional current transformers all around the power grid. Moreover, the optical sensor is more stable, more accurate and faster, with such characteristics, the smart grid monitoring system could be much better. The application of combining the optical composite low-voltage cable (OPLC) and the optical current sensor in the distribution network for smart distribution monitoring has been analyzed.展开更多
The article describes design peculiarities of the novel compact vacuum circuit breaker with rated voltage 40.5 kV. The design incorporates several novel technical solutions： polycarbonate support insulation, mono-sta...The article describes design peculiarities of the novel compact vacuum circuit breaker with rated voltage 40.5 kV. The design incorporates several novel technical solutions： polycarbonate support insulation, mono-stable magnetic actuator, labyrinth pulling insulator, core-type flexible contact and new compact vacuum interrupter （VI）. Phases are encapsulated into silicone rubber providing required creepage distance and excellent tracking resistance. These novelties along with extensive modeling of the mechanical and electrical fields followed by design optimization resulted in weight reduction of more than 50% compared with alternatives available in the market. And this is in spite of built in sensors measuring： phase currents, zero-sequence current, phase voltages.展开更多
Large-conductance Ca^(2+)-activated K+channels(BK channels)constitute an key physiological link between cellular Ca^(2+) signaling and electrical signaling at the plasma membrane.Thus these channels are critical to th...Large-conductance Ca^(2+)-activated K+channels(BK channels)constitute an key physiological link between cellular Ca^(2+) signaling and electrical signaling at the plasma membrane.Thus these channels are critical to the control of action potential firing and neurotrans-mitter release in several types of neurons,as well as the dynamic control of smooth muscle tone in resis-tance arteries,airway,and bladder.Recent advances in our understanding of K^(+) channel structure and function have led to new insight toward the molecular mecha-nisms of opening and closing(gating)of these chan-nels.Here we will focus on mechanisms of BK channel gating by Ca^(2+),transmembrane voltage,and auxiliary subunit proteins.展开更多
Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its...Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.展开更多
基金National Natural Science Foundation of China(Nos.51767013,52067013)。
文摘In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.
文摘This paper concludes the case study work on the optical sensor, which is a new method for voltage and current measurement. Fiber Bragg gratings (FBG) have been developed and used for decades in the telecommunication industry. In recent years, FBG sensors have found wide applications in monitoring strain, temperature, voltage and current across all industries. As the process of constructing a robust smart grid, thousands of miles of optical-fibers have been deployed along the power transmission lines for the purpose of power production communication. This paper focuses on using the power optical fiber as voltage/current sensors instead of those copper wired traditional current transformers. By using piezoelectric layers, the optical sensor is able to transform voltage/current magnitude into optical signal, as well as transmit the signal through the optical fiber. The application of using optical fiber will significantly reduce the cost of deploying traditional current transformers all around the power grid. Moreover, the optical sensor is more stable, more accurate and faster, with such characteristics, the smart grid monitoring system could be much better. The application of combining the optical composite low-voltage cable (OPLC) and the optical current sensor in the distribution network for smart distribution monitoring has been analyzed.
文摘The article describes design peculiarities of the novel compact vacuum circuit breaker with rated voltage 40.5 kV. The design incorporates several novel technical solutions： polycarbonate support insulation, mono-stable magnetic actuator, labyrinth pulling insulator, core-type flexible contact and new compact vacuum interrupter （VI）. Phases are encapsulated into silicone rubber providing required creepage distance and excellent tracking resistance. These novelties along with extensive modeling of the mechanical and electrical fields followed by design optimization resulted in weight reduction of more than 50% compared with alternatives available in the market. And this is in spite of built in sensors measuring： phase currents, zero-sequence current, phase voltages.
基金supported in part by the National Institute of General Medical Science of the National Institutes of Health(Grant No.R01GM068523).
文摘Large-conductance Ca^(2+)-activated K+channels(BK channels)constitute an key physiological link between cellular Ca^(2+) signaling and electrical signaling at the plasma membrane.Thus these channels are critical to the control of action potential firing and neurotrans-mitter release in several types of neurons,as well as the dynamic control of smooth muscle tone in resis-tance arteries,airway,and bladder.Recent advances in our understanding of K^(+) channel structure and function have led to new insight toward the molecular mecha-nisms of opening and closing(gating)of these chan-nels.Here we will focus on mechanisms of BK channel gating by Ca^(2+),transmembrane voltage,and auxiliary subunit proteins.
文摘Plants and animals in endosomes operate TPCI/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation ap- proaches, enabling structure-function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta.
