Complex dynamical phenomenon was studied in the single phase H-bridge inverter which was controlled by either a peak current or a valley current. The state functions and the discrete iterative map equations were estab...Complex dynamical phenomenon was studied in the single phase H-bridge inverter which was controlled by either a peak current or a valley current. The state functions and the discrete iterative map equations were established to analyze the dynamical phenomenon in the single phase H-bridge inverter. The dynamical characteristics of the single phase H- bridge inverter, such as time domain waveform diagram, bifurcation diagram, and folding map, were obtained by using the numerical calculation when the circuit parameters varied in specific range. Moreover, the simulation results were obtained by using the OrCAD-PSpice software to validate the numerical calculation. Both the numerical calculation and the circuit simulation show that the symmetrical dynamical phenomenon occurs in the single phase H-bridge inverter controlled by the peak current or the valley current.展开更多
The BUAA-BWB remotely piloted vehicle （RPV） designed by our research team encountered an unexpected landing safety problem in flight tests. It has obviously affected further research project for blended-wing-body （...The BUAA-BWB remotely piloted vehicle （RPV） designed by our research team encountered an unexpected landing safety problem in flight tests. It has obviously affected further research project for blended-wing-body （BWB） aircraft configuration characteristics. Searching for a safety improvement is an urgent requirement in the development work of the RPV. In view of the vehicle characteristics, a new systemic method called system-theoretic process analysis （STPA） has been tentatively applied to the hazardous factor analysis of the RPV flight test. An uncontrolled system behavior ＂path sagging phenomenon＂ is identified by implementing a three degrees of freedom simulation based on wind tunnel test data and establishing landing safety system dynamics archetype. To obtain higher safety design effectiveness and considering safety design precedence, a longitudinal ＂belly-flap＂ control surface is innovatively introduced and designed to eliminate hazards in landing. Finally, flight tests show that the unsafe factor has been correctly identified and the landing safety has been efficiently improved.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51107016)the National Basic Research Program of China(Grant No.2013CB035605)the Postdoctoral Science Research Developmental Foundation of Heilongjiang Province,China(Grant No.LHB-Q12086)
文摘Complex dynamical phenomenon was studied in the single phase H-bridge inverter which was controlled by either a peak current or a valley current. The state functions and the discrete iterative map equations were established to analyze the dynamical phenomenon in the single phase H-bridge inverter. The dynamical characteristics of the single phase H- bridge inverter, such as time domain waveform diagram, bifurcation diagram, and folding map, were obtained by using the numerical calculation when the circuit parameters varied in specific range. Moreover, the simulation results were obtained by using the OrCAD-PSpice software to validate the numerical calculation. Both the numerical calculation and the circuit simulation show that the symmetrical dynamical phenomenon occurs in the single phase H-bridge inverter controlled by the peak current or the valley current.
基金National Natural Science Foundation of China (60832012)National High-tech Research and Development Program of China (2006AA11Z219)+1 种基金supported by Cheung Kong Scholars Innovation Team of Aero-Engine Complex System Safety of Ministry of Education of the People’s Republic of China (IRT 0905)Beijing Key Laboratory on Safety of Integrated Aircraft and Propulsion Systems
文摘The BUAA-BWB remotely piloted vehicle （RPV） designed by our research team encountered an unexpected landing safety problem in flight tests. It has obviously affected further research project for blended-wing-body （BWB） aircraft configuration characteristics. Searching for a safety improvement is an urgent requirement in the development work of the RPV. In view of the vehicle characteristics, a new systemic method called system-theoretic process analysis （STPA） has been tentatively applied to the hazardous factor analysis of the RPV flight test. An uncontrolled system behavior ＂path sagging phenomenon＂ is identified by implementing a three degrees of freedom simulation based on wind tunnel test data and establishing landing safety system dynamics archetype. To obtain higher safety design effectiveness and considering safety design precedence, a longitudinal ＂belly-flap＂ control surface is innovatively introduced and designed to eliminate hazards in landing. Finally, flight tests show that the unsafe factor has been correctly identified and the landing safety has been efficiently improved.
