A new low power quasi adiabatic logic,complementary pass transistor adiabatic logic (CPAL),is presented.The CPAL circuit is driven by a new three phase power clock,and its non adiabatic loss on output loads can b...A new low power quasi adiabatic logic,complementary pass transistor adiabatic logic (CPAL),is presented.The CPAL circuit is driven by a new three phase power clock,and its non adiabatic loss on output loads can be effectively reduced by using complementary pass transistor logic and transmission gates.Furthermore,the minimization of the energy consumption can be obtained by choosing the optimal size of bootstrapped nMOS transistors,thus it has more efficient energy transfer and recovery.A three phase power supply generator with a small control logic circuit and a single inductor is proposed.An 8 bit adder based on CPAL is designed and verified.With MOSIS 0 25μm CMOS technology,the CPAL adder consumes only 35% of the dissipated energy of a 2N 2N2P adder and is about 50% of the dissipated energy of a PFAL adder for clock rates ranging from 50 to 200MHz.展开更多
For three phase four-wire active power filters （APFs）, several typical power theories and corresponding current reference generation strategies are induced, p-q, d-q, unify power factor （UPF） and instantaneous act...For three phase four-wire active power filters （APFs）, several typical power theories and corresponding current reference generation strategies are induced, p-q, d-q, unify power factor （UPF） and instantaneous active current （IAC） methods are analyzed and compared with each other. The interpretation of active and reactive currents in non-sinusoidal and unbalanced three-phase four-wire systems is given based on the generalized instantaneous reactive power theory. The performance and the characteristic are evaluated, and the application conditions of current reference generation strategies are concluded. Simulation results under different source voltages and loads verify the evaluation result.展开更多
To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier emp...To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.展开更多
Vertical distributions of void fraction in gas-liquid and gas-liquid-solid stirred tanks have been measured in a fully baffled dished base vessel of 0.48 m diameter, using a conductivity probe. The impeller configurat...Vertical distributions of void fraction in gas-liquid and gas-liquid-solid stirred tanks have been measured in a fully baffled dished base vessel of 0.48 m diameter, using a conductivity probe. The impeller configuration （a hollow half elliptical blade dispersing turbine below two up-pumping wide blade hydrofoils, identified as HEDT＋2WHu） recommended in previous work has been used in this work. The operating temperatures were 24℃ and 81℃, identified as cold and hot respectively. The effects of superficial gas velocity, agitator speed and the corresponding power input on the local void fraction in two-phase systems are .investigated and discussed. Results show thatth-e increasing of agitator speed or gas flow rate leads to an increase in local-void fraction at the majority of measurement points in both cold and hot systems. However, the unifo,rmity of gas dispersion does not always in crease as the raising of agitator speed and power input. In either cold or hot sparged conditions, the two- and three-phase systems.have similar vertical profiles for void fraction, with maxima in similar locations; however, the void fractions are significantly lower in hot sparging than with cold. In cold operation the presence of particles leads to a lower void fraction at most points, although the local void fractions increase a little with the addition of solid particles at high temperature, in good agreement with the global gas holdup results, and the possible reasons are discussed in this paper. This work can give a better understanding of the differences between cold-gassed and hot-sparged three phase＇stirred tanks.展开更多
文摘A new low power quasi adiabatic logic,complementary pass transistor adiabatic logic (CPAL),is presented.The CPAL circuit is driven by a new three phase power clock,and its non adiabatic loss on output loads can be effectively reduced by using complementary pass transistor logic and transmission gates.Furthermore,the minimization of the energy consumption can be obtained by choosing the optimal size of bootstrapped nMOS transistors,thus it has more efficient energy transfer and recovery.A three phase power supply generator with a small control logic circuit and a single inductor is proposed.An 8 bit adder based on CPAL is designed and verified.With MOSIS 0 25μm CMOS technology,the CPAL adder consumes only 35% of the dissipated energy of a 2N 2N2P adder and is about 50% of the dissipated energy of a PFAL adder for clock rates ranging from 50 to 200MHz.
文摘For three phase four-wire active power filters （APFs）, several typical power theories and corresponding current reference generation strategies are induced, p-q, d-q, unify power factor （UPF） and instantaneous active current （IAC） methods are analyzed and compared with each other. The interpretation of active and reactive currents in non-sinusoidal and unbalanced three-phase four-wire systems is given based on the generalized instantaneous reactive power theory. The performance and the characteristic are evaluated, and the application conditions of current reference generation strategies are concluded. Simulation results under different source voltages and loads verify the evaluation result.
基金Natural Science Foundation of Gansu Province Education Department(No.2017A-020)National Natural Science Foundation of China(No.51767013)Science and Technology Research and Development Plan of China Railway Corporation(No.2017J012-A)
文摘To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.
基金Supported by the National Natural Science Foundation of China （20576009, 20821004） and the National Basic Research Program of China （2007CB714300）. ACKNOWLEDGEMENTS The authors sincerely acknowledge the helpful discussion with Prof John M. Smith [Fluids and Systems Research Centre, School of Engineering （J2）, University of Surrey, Guildford, GU2 7XH, UK].
文摘Vertical distributions of void fraction in gas-liquid and gas-liquid-solid stirred tanks have been measured in a fully baffled dished base vessel of 0.48 m diameter, using a conductivity probe. The impeller configuration （a hollow half elliptical blade dispersing turbine below two up-pumping wide blade hydrofoils, identified as HEDT＋2WHu） recommended in previous work has been used in this work. The operating temperatures were 24℃ and 81℃, identified as cold and hot respectively. The effects of superficial gas velocity, agitator speed and the corresponding power input on the local void fraction in two-phase systems are .investigated and discussed. Results show thatth-e increasing of agitator speed or gas flow rate leads to an increase in local-void fraction at the majority of measurement points in both cold and hot systems. However, the unifo,rmity of gas dispersion does not always in crease as the raising of agitator speed and power input. In either cold or hot sparged conditions, the two- and three-phase systems.have similar vertical profiles for void fraction, with maxima in similar locations; however, the void fractions are significantly lower in hot sparging than with cold. In cold operation the presence of particles leads to a lower void fraction at most points, although the local void fractions increase a little with the addition of solid particles at high temperature, in good agreement with the global gas holdup results, and the possible reasons are discussed in this paper. This work can give a better understanding of the differences between cold-gassed and hot-sparged three phase＇stirred tanks.
