Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization targets.Onboard DC electric networks are facing great challenges in DC fault protection requirements.Vacuum int...Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization targets.Onboard DC electric networks are facing great challenges in DC fault protection requirements.Vacuum interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low maintenance.In this paper a moving coil actuator with compensation coils for a vacuum interrupter,as part of a hybrid direct current circuit breaker,is designed and experimentally tested.Compensation coils are used to improve operating speed compared with original moving coil actuator.Comparisons between four possible connections of compensation coils and original moving coil actuator are carried out.Experimental results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor voltages.Dynamic performance of each actuator connection is also compared.The actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed,which is a critical requirement for electric aircraft network protection.The parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.展开更多
三线圈结构能够有效提升无线电能传输(Wireless Power Transfer,WPT)系统传输距离.S/S/S拓扑因简单实用而广泛应用于三线圈WPT系统,但传统的完全补偿方法令各线圈自感与补偿电容形成串联谐振,受线圈耦合及负载条件影响,系统无法在不同...三线圈结构能够有效提升无线电能传输(Wireless Power Transfer,WPT)系统传输距离.S/S/S拓扑因简单实用而广泛应用于三线圈WPT系统,但传统的完全补偿方法令各线圈自感与补偿电容形成串联谐振,受线圈耦合及负载条件影响,系统无法在不同工况下均达到最佳传输效率.针对这一问题,提出一种非完全补偿的S/S/S拓扑参数配置方法 .首先,通过对传统补偿方法分析,阐明了完全补偿时系统效率不佳的原因.然后,以线圈传导损耗最小为目标,采用非线性规划方法对中继和接收线圈补偿参数进行优化,同时匹配发射线圈最佳补偿参数以减小功率器件开关损耗.最后,通过仿真分析得到采用非完全补偿方法时的系统特性,揭示系统效率提升的内在机理,并以输出功率为1 kW的三线圈WPT系统为例开展实验研究.结果表明:与完全补偿方法相比,采用所提非完全补偿方法的系统AC-AC效率提高5.183%、输入电压降低85.3%;与中继线圈切换方法相比,AC-AC效率提高4.214%;所提方法能够实现逆变器功率器件的软开关和系统最优效率,增强三线圈WPT系统的实用性.展开更多
The stress-strain state of the structure is a matter of interest to designer. The strain measurement of superconducting magnets at cryogenic temperature is a specific technique. Based on strain measurement of TF coil ...The stress-strain state of the structure is a matter of interest to designer. The strain measurement of superconducting magnets at cryogenic temperature is a specific technique. Based on strain measurement of TF coil case for EAST, this paper presents a measuring technique at cryogenic temperature and on intense magnetic field. The compensation methods for both temperature and magnetic field effects of the gauges, together with the measured results are involved, and the discussions of the measured results are given in the paper.展开更多
DC circuit breakers are major enabling components for multi-terminal HVDC systems.Their key design targets are operating speed and efficiency.This paper proposes a novel moving coil actuator using a compensation coil ...DC circuit breakers are major enabling components for multi-terminal HVDC systems.Their key design targets are operating speed and efficiency.This paper proposes a novel moving coil actuator using a compensation coil topology to operate mechanical circuit breakers.This topology aims to significantly improve the magnetic field saturation and reduce the system inductance,so that the operating speed is increased.Four possible connection methods for the compensation coils are proposed and analyzed using finite element modeling,ensuing simulation results are compared and discussed.The operating speed of the moving coil actuator with compensation coils is significantly improved compared with the original moving coil actuator.The moving coil actuator with compensation coils can open a distance of 5 mm within 2.8 ms and the peak efficiency is 47%.展开更多
基金supported in part by the UK Aerospace Technology Institute under contract 103136-Zero Emissions for Sustainable Transport 1(ZEST 1).
文摘Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization targets.Onboard DC electric networks are facing great challenges in DC fault protection requirements.Vacuum interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low maintenance.In this paper a moving coil actuator with compensation coils for a vacuum interrupter,as part of a hybrid direct current circuit breaker,is designed and experimentally tested.Compensation coils are used to improve operating speed compared with original moving coil actuator.Comparisons between four possible connections of compensation coils and original moving coil actuator are carried out.Experimental results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor voltages.Dynamic performance of each actuator connection is also compared.The actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed,which is a critical requirement for electric aircraft network protection.The parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.
文摘三线圈结构能够有效提升无线电能传输(Wireless Power Transfer,WPT)系统传输距离.S/S/S拓扑因简单实用而广泛应用于三线圈WPT系统,但传统的完全补偿方法令各线圈自感与补偿电容形成串联谐振,受线圈耦合及负载条件影响,系统无法在不同工况下均达到最佳传输效率.针对这一问题,提出一种非完全补偿的S/S/S拓扑参数配置方法 .首先,通过对传统补偿方法分析,阐明了完全补偿时系统效率不佳的原因.然后,以线圈传导损耗最小为目标,采用非线性规划方法对中继和接收线圈补偿参数进行优化,同时匹配发射线圈最佳补偿参数以减小功率器件开关损耗.最后,通过仿真分析得到采用非完全补偿方法时的系统特性,揭示系统效率提升的内在机理,并以输出功率为1 kW的三线圈WPT系统为例开展实验研究.结果表明:与完全补偿方法相比,采用所提非完全补偿方法的系统AC-AC效率提高5.183%、输入电压降低85.3%;与中继线圈切换方法相比,AC-AC效率提高4.214%;所提方法能够实现逆变器功率器件的软开关和系统最优效率,增强三线圈WPT系统的实用性.
基金The project supported by the National Meg-Science Engineering project of the Chinese Government
文摘The stress-strain state of the structure is a matter of interest to designer. The strain measurement of superconducting magnets at cryogenic temperature is a specific technique. Based on strain measurement of TF coil case for EAST, this paper presents a measuring technique at cryogenic temperature and on intense magnetic field. The compensation methods for both temperature and magnetic field effects of the gauges, together with the measured results are involved, and the discussions of the measured results are given in the paper.
文摘DC circuit breakers are major enabling components for multi-terminal HVDC systems.Their key design targets are operating speed and efficiency.This paper proposes a novel moving coil actuator using a compensation coil topology to operate mechanical circuit breakers.This topology aims to significantly improve the magnetic field saturation and reduce the system inductance,so that the operating speed is increased.Four possible connection methods for the compensation coils are proposed and analyzed using finite element modeling,ensuing simulation results are compared and discussed.The operating speed of the moving coil actuator with compensation coils is significantly improved compared with the original moving coil actuator.The moving coil actuator with compensation coils can open a distance of 5 mm within 2.8 ms and the peak efficiency is 47%.
