A protection system using a multi-agent concept for power distribution networks is proposed.Every digital over current relay(OCR)is developed as an agent by adding its own intelligence,self-tuning and communication ab...A protection system using a multi-agent concept for power distribution networks is proposed.Every digital over current relay(OCR)is developed as an agent by adding its own intelligence,self-tuning and communication ability.The main advantage of the multi-agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent.In order to cope with frequent changes in the network operation condition and faults,an OCR agent,proposed in this paper,is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents.Through this kind of coordination and information exchanges,not only a local but also a global protective scheme is completed.Simulations in a simple distribution network show the effectiveness of the proposed protection system.展开更多
A high linearity current communicating passive mixer including the mixing cell and transimpedance amplifier(TIA) is introduced.It employs the resistor in the TIA to reduce the source voltage and the gate voltage of th...A high linearity current communicating passive mixer including the mixing cell and transimpedance amplifier(TIA) is introduced.It employs the resistor in the TIA to reduce the source voltage and the gate voltage of the mixing cell.The optimum linearity and the maximum symmetric switching operation are obtained at the same time.The mixer is implemented in a 0.25μm CMOS process.The test shows that it achieves an input third-order intercept point of 13.32 dBm,conversion gain of 5.52 dB,and a single sideband noise figure of 20 dB.展开更多
A wideband large dynamic range and high linearity U-band RF front-end for mobile DTV is introduced, and includes a noise-cancelling low-noise amplifier （LNA）, an RF programmable gain amplifier （RFPGA） and a curren...A wideband large dynamic range and high linearity U-band RF front-end for mobile DTV is introduced, and includes a noise-cancelling low-noise amplifier （LNA）, an RF programmable gain amplifier （RFPGA） and a current communicating passive mixer. The noise/distortion cancelling structure and RC post-distortion compensation are employed to improve the linearity of the LNA. An RFPGA with five stages provides large dynamic range and fine gain resolution. A simple resistor voltage network in the passive mixer decreases the gate bias voltage of the mixing transistor, and optimum linearity and symmetrical mixing is obtained at the same time. The RF front-end is implemented in a 0.25 #m CMOS process. Tests show that it achieves an IIP3 （third-order intercept point） of -17 dBm, a conversion gain of 39 dB, and a noise figure of 5.8 dB. The RFPGA achieves a dynamic range of-36.2 to 23.5 dB with a resolution of 0.32 dB.展开更多
文摘A protection system using a multi-agent concept for power distribution networks is proposed.Every digital over current relay(OCR)is developed as an agent by adding its own intelligence,self-tuning and communication ability.The main advantage of the multi-agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent.In order to cope with frequent changes in the network operation condition and faults,an OCR agent,proposed in this paper,is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents.Through this kind of coordination and information exchanges,not only a local but also a global protective scheme is completed.Simulations in a simple distribution network show the effectiveness of the proposed protection system.
基金supported by the National High Technology R&D Program ofChina(No.2011AA040102)the National Science and Technology Major Project ofthe Ministry of Science and Technology of China(No.2009ZX01031-002-008-002)
文摘A high linearity current communicating passive mixer including the mixing cell and transimpedance amplifier(TIA) is introduced.It employs the resistor in the TIA to reduce the source voltage and the gate voltage of the mixing cell.The optimum linearity and the maximum symmetric switching operation are obtained at the same time.The mixer is implemented in a 0.25μm CMOS process.The test shows that it achieves an input third-order intercept point of 13.32 dBm,conversion gain of 5.52 dB,and a single sideband noise figure of 20 dB.
基金supported by the National High-Tech R&D Program of China(No.2011AA040102)the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2009ZX01031-002-008-002)
文摘A wideband large dynamic range and high linearity U-band RF front-end for mobile DTV is introduced, and includes a noise-cancelling low-noise amplifier （LNA）, an RF programmable gain amplifier （RFPGA） and a current communicating passive mixer. The noise/distortion cancelling structure and RC post-distortion compensation are employed to improve the linearity of the LNA. An RFPGA with five stages provides large dynamic range and fine gain resolution. A simple resistor voltage network in the passive mixer decreases the gate bias voltage of the mixing transistor, and optimum linearity and symmetrical mixing is obtained at the same time. The RF front-end is implemented in a 0.25 #m CMOS process. Tests show that it achieves an IIP3 （third-order intercept point） of -17 dBm, a conversion gain of 39 dB, and a noise figure of 5.8 dB. The RFPGA achieves a dynamic range of-36.2 to 23.5 dB with a resolution of 0.32 dB.
