The definition of reactive power for non-sinusoidal conditions is a controversial issue.The mathematical treatment of nonlinear loads in power systems is also unsettled.This paper starts with the decomposing of appare...The definition of reactive power for non-sinusoidal conditions is a controversial issue.The mathematical treatment of nonlinear loads in power systems is also unsettled.This paper starts with the decomposing of apparent power in the cases of linear and nonlinear loads.When harmonics are present,apparent power is composed of active power,reactive power,and disturbed reactive power.Linear element can be defined as the element without disturbed reactive power.This definition is based on a practical engineering concept which can separate the contribution from the apparent power into utility-duty part and custom-duty part.The field investigation of home-used facilities was conducted.Also the data acquisition in the 0.4 kV distribution systems was completed.Moreover,the loss increase due to the nonlinear loads was estimated.Nonlinear loads can be a dominant effect with respect to reactive power and power factor.Field data from a number of nonlinear load types indicate that the disturbed reactive power can cause significant losses in utility supply systems.展开更多
This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two G...This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two Gilbert cells it was applied quadrature modulation. Operational ampli- tiers are used in this design to improve the conversion gain under low power consumption. The mixer design is based on 0.18txm RF CMOS process. And the mixer test results indicate that under 1.8V power supply, with input frequency 2.4 - 2.4835GHz, the conversion voltage gain is 1.2 - 2dB. When the output frequency is 2.4GHz, its power gain is -4.46dB, and its input referred 1 dB com- pression point is -11.5dBm and it consumes 1.77mA current.展开更多
文摘The definition of reactive power for non-sinusoidal conditions is a controversial issue.The mathematical treatment of nonlinear loads in power systems is also unsettled.This paper starts with the decomposing of apparent power in the cases of linear and nonlinear loads.When harmonics are present,apparent power is composed of active power,reactive power,and disturbed reactive power.Linear element can be defined as the element without disturbed reactive power.This definition is based on a practical engineering concept which can separate the contribution from the apparent power into utility-duty part and custom-duty part.The field investigation of home-used facilities was conducted.Also the data acquisition in the 0.4 kV distribution systems was completed.Moreover,the loss increase due to the nonlinear loads was estimated.Nonlinear loads can be a dominant effect with respect to reactive power and power factor.Field data from a number of nonlinear load types indicate that the disturbed reactive power can cause significant losses in utility supply systems.
基金Supported by the National High Technology Research and Development Program(No.2007AA01Z2A7)the Special Fund of Jiangsu Province for the Transformation of Scientific and Technological Achievements(No.BA2010073)
文摘This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two Gilbert cells it was applied quadrature modulation. Operational ampli- tiers are used in this design to improve the conversion gain under low power consumption. The mixer design is based on 0.18txm RF CMOS process. And the mixer test results indicate that under 1.8V power supply, with input frequency 2.4 - 2.4835GHz, the conversion voltage gain is 1.2 - 2dB. When the output frequency is 2.4GHz, its power gain is -4.46dB, and its input referred 1 dB com- pression point is -11.5dBm and it consumes 1.77mA current.
