Novel transformer active filters
Novel transformer active filters are proposed to obtain high attenuation of voltage or current ripple without deteriorating the transient response of the system considered. Experimental results show that the scheme gives good steady-state performance of the power supply. >
Novel load ripple voltage-controlled parallel DC active power filters for high performance magnet power supplies
The cooling storage ring of the heavy ion research facility in Lanzhou (HIRFL-CSR) is one of the five mega-science projects undertaken by Chinese Academy of Science within its ninth and tenth five-year plan period. The HIRFL-CSR facility can providing heavy ion beams in wide energy range, manifold and with high quality. This paper presents a hybrid filter structure consisting of a passive filter and a parallel dc active power filter (DCAPF) for a sample magnet power supply in HIRFL-CSR. The configuration of the power system with the DCAPF is introduced. Then a novel feedback control scheme for the DCAPF is proposed with detecting the output ripple voltage across the magnet load. For detailed discussion, a simple model of the whole system has been derived and the stability characteristic is analyzed. Through simulation and experiment investigation, the DCAPF is successfully applied in a 120-kW magnet power supply in HIRFL-CSR finally. The ripple factor and tracking accuracy of the output current through the load achieve 8.87 ppm and 100 ppm, respectively. Therefore, the rigor requirements of low output current ripple and fast ramp rate are both satisfied with the DCAPF proposed.
Far-field dispersal modeling for fuel-air-explosive devices
A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.