The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing appro...The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.展开更多
A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production...A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production. The test loop was installed in the Korea Atomic Energy Research Institute （KAERI） facility to confirm the integrity of the sulfur trioxide decomposer, one of the key components in the test loop, under HTGR operating conditions. In this paper, the simulation using Aspen plus, a chemical process simulator, was made to evaluate the performance of a sulfur trioxide decomposer. The simulation indicated that at least 10 kW heat needs to be supplied to the sulfur trioxide decomposer in the test loop when the sulfuric acid flowrate is 0.5 kg/min. The simulation flowsheet was obtained and the material balance around the sulfur trioxide decomposer was determined in case of 10 kW heat input and 0.5 kg/min flowrate of liquid sulfuric acid. The parametric study was carried out for sulfur trioxide decomposer. It indicated that the moles of sulfur dioxide produced at the decomposer increases as the operating temperature increases and is decreasing as the operating pressure becomes higher at a given temperature. The parametric study also indicated water vapor removal out of the decomposer is a less effective method to increase the sulfur trioxide conversion ratio.展开更多
This paper presents a framework of a multi-terminal HVDC transmission system and its multi-functional control strategy.The framework possesses the basic characteristics of the DC-grid and is suitable in integrating di...This paper presents a framework of a multi-terminal HVDC transmission system and its multi-functional control strategy.The framework possesses the basic characteristics of the DC-grid and is suitable in integrating distributed power sources.The paper proposes the first architecture for a multiterminal HVDC transmission system using the VSC technology.Its control strategy offers various functionalities that include controls for operation mode,start-up and shutdown,DC voltage,and station online re-connecting,which are significantly different from the control of point-to-point VSC-HVDC systems.The framework has not only been evaluated in real-time simulation studies,but has also been implemented onsite for the first time via the China Southern Grid's Nan'ao Multi-terminal VSCHVDC(VSC-MTDC)project.This paper gives a brief review of the current research and engineering achievements in this field,which includes four aspects:the architecture of the VSCMTDC system,the structure of the control and protection system,simulation verification tests setting,and the results of real-time hardware in hardware in loop(HIL)simulation studies and onsite tests.展开更多
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2007AA04Z436)
文摘The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.
文摘A High Temperature Gas Cooled Reactor （HTGR） with an outlet coolant temperature of 950 ℃ is considered as an efficient reactor to couple with the thermo-chemical Sulfur Iodine （SI） cycle for a hydrogen production. The test loop was installed in the Korea Atomic Energy Research Institute （KAERI） facility to confirm the integrity of the sulfur trioxide decomposer, one of the key components in the test loop, under HTGR operating conditions. In this paper, the simulation using Aspen plus, a chemical process simulator, was made to evaluate the performance of a sulfur trioxide decomposer. The simulation indicated that at least 10 kW heat needs to be supplied to the sulfur trioxide decomposer in the test loop when the sulfuric acid flowrate is 0.5 kg/min. The simulation flowsheet was obtained and the material balance around the sulfur trioxide decomposer was determined in case of 10 kW heat input and 0.5 kg/min flowrate of liquid sulfuric acid. The parametric study was carried out for sulfur trioxide decomposer. It indicated that the moles of sulfur dioxide produced at the decomposer increases as the operating temperature increases and is decreasing as the operating pressure becomes higher at a given temperature. The parametric study also indicated water vapor removal out of the decomposer is a less effective method to increase the sulfur trioxide conversion ratio.
基金supported by the 863 National High Technology Research and Development Program of China(2011AA05AI02)China Southern Power Grid Company.
文摘This paper presents a framework of a multi-terminal HVDC transmission system and its multi-functional control strategy.The framework possesses the basic characteristics of the DC-grid and is suitable in integrating distributed power sources.The paper proposes the first architecture for a multiterminal HVDC transmission system using the VSC technology.Its control strategy offers various functionalities that include controls for operation mode,start-up and shutdown,DC voltage,and station online re-connecting,which are significantly different from the control of point-to-point VSC-HVDC systems.The framework has not only been evaluated in real-time simulation studies,but has also been implemented onsite for the first time via the China Southern Grid's Nan'ao Multi-terminal VSCHVDC(VSC-MTDC)project.This paper gives a brief review of the current research and engineering achievements in this field,which includes four aspects:the architecture of the VSCMTDC system,the structure of the control and protection system,simulation verification tests setting,and the results of real-time hardware in hardware in loop(HIL)simulation studies and onsite tests.
