A cryogenic low noise amplifier （LNA） using Agilent high electron mobility transistor （HEMT） for 380 MHzto 480 MHz is designed and fabricated, and the excellent cryogenic performance in superconducting receiver fr...A cryogenic low noise amplifier （LNA） using Agilent high electron mobility transistor （HEMT） for 380 MHzto 480 MHz is designed and fabricated, and the excellent cryogenic performance in superconducting receiver front-end for communication system is achieved. A special input impedance matching topology is implemented to provide low noise figure （NF） and good input matching in this cryogenic LNA design. The measurement results show that the NF is within 0.25 dB from the minimum NF of a single transistor, the power gain is above 20 dB, the flatness is within 1 dB, and the maximum input return loss is lower than -20 dB in bandwidth.展开更多
Modern eco-friendly industries such as renewable energy systems,electric vehicles(EVs),and light-emitting diodes(LEDs)have led to technological advancements in power electronics.Switching-based power converters have l...Modern eco-friendly industries such as renewable energy systems,electric vehicles(EVs),and light-emitting diodes(LEDs)have led to technological advancements in power electronics.Switching-based power converters have limited working ranges and can cause significant harmonics and oscillations in the output voltage and current.Introducing variable inductors can help solve this problem by changing the inductance without resorting to extreme switch duty cycles.Despite their advantages,there is still a lack of comprehensive reviews of variable inductor applications in power converter design.A thorough and in-depth review of variable inductance control in power conversion is presented,including its significance,working principle,core structure,modeling method,and typical applications.Traditionally,an inductor works in its linear magnetic region;its inductance in a power converter is considered constant,and the converter operates under fixed working conditions.However,a broad range of working conditions is required for power converters in practical applications.This is typically realized by changing the duty cycles of the switches.The working principle of variable inductance is reviewed,and the application of variable inductance control in power converters is presented,which will further help power electronics researchers and engineers design flexible and resilient power converters.展开更多
Herein,we propose a novel three-phase quasi-Z-source inverter with a high voltage transmission ratio to address challenges such as high switching loss and sizeable magnetic components in the basic quasi-Z-source inver...Herein,we propose a novel three-phase quasi-Z-source inverter with a high voltage transmission ratio to address challenges such as high switching loss and sizeable magnetic components in the basic quasi-Z-source inverter.The proposed circuit topology,control strategy,and related analysis are presented.The circuit topology of the inverter comprises a quasi-Z-source network with an integrated magnetic inductor,an active clamp circuit,a three-phase inverter bridge,and an output LC filter,all of which are connected in series.An improved 12-sector space vector modulation scheme is proposed based on the root-mean-square value of the voltage and the instantaneous value of the current.Furthermore,analyses of the inverter voltage transmission ratio,resonant process,and parametric design guidelines for integrated magnetic inductor and zero-voltage switching conditions are presented.Experimental results on a 1-kVA prototype inverter demonstrate that the proposed inverter exhibits a higher transmission ratio and efficiency than existing inverters;thus,the proposed inverter would have broad prospects in low-voltage DC-AC applications.展开更多
基金This work was supported by the National Nature Science Foundation of China under Grant No. 60471001.
文摘A cryogenic low noise amplifier （LNA） using Agilent high electron mobility transistor （HEMT） for 380 MHzto 480 MHz is designed and fabricated, and the excellent cryogenic performance in superconducting receiver front-end for communication system is achieved. A special input impedance matching topology is implemented to provide low noise figure （NF） and good input matching in this cryogenic LNA design. The measurement results show that the NF is within 0.25 dB from the minimum NF of a single transistor, the power gain is above 20 dB, the flatness is within 1 dB, and the maximum input return loss is lower than -20 dB in bandwidth.
基金Supported by Natural Science Foundation for Distinguished Young Scholars of Guangdong Province under No.2022B1515020002。
文摘Modern eco-friendly industries such as renewable energy systems,electric vehicles(EVs),and light-emitting diodes(LEDs)have led to technological advancements in power electronics.Switching-based power converters have limited working ranges and can cause significant harmonics and oscillations in the output voltage and current.Introducing variable inductors can help solve this problem by changing the inductance without resorting to extreme switch duty cycles.Despite their advantages,there is still a lack of comprehensive reviews of variable inductor applications in power converter design.A thorough and in-depth review of variable inductance control in power conversion is presented,including its significance,working principle,core structure,modeling method,and typical applications.Traditionally,an inductor works in its linear magnetic region;its inductance in a power converter is considered constant,and the converter operates under fixed working conditions.However,a broad range of working conditions is required for power converters in practical applications.This is typically realized by changing the duty cycles of the switches.The working principle of variable inductance is reviewed,and the application of variable inductance control in power converters is presented,which will further help power electronics researchers and engineers design flexible and resilient power converters.
基金the National Natural Science Foundation of China(Grant No.51537001)Fund of“Taishan Scholar”Climbing Plan of Shandong Province,China。
文摘Herein,we propose a novel three-phase quasi-Z-source inverter with a high voltage transmission ratio to address challenges such as high switching loss and sizeable magnetic components in the basic quasi-Z-source inverter.The proposed circuit topology,control strategy,and related analysis are presented.The circuit topology of the inverter comprises a quasi-Z-source network with an integrated magnetic inductor,an active clamp circuit,a three-phase inverter bridge,and an output LC filter,all of which are connected in series.An improved 12-sector space vector modulation scheme is proposed based on the root-mean-square value of the voltage and the instantaneous value of the current.Furthermore,analyses of the inverter voltage transmission ratio,resonant process,and parametric design guidelines for integrated magnetic inductor and zero-voltage switching conditions are presented.Experimental results on a 1-kVA prototype inverter demonstrate that the proposed inverter exhibits a higher transmission ratio and efficiency than existing inverters;thus,the proposed inverter would have broad prospects in low-voltage DC-AC applications.
