当前大功率直流电源普遍采用直流链接技术和无源功率因数校正方案,电网侧电流谐波较大、功率因数较低且尺寸较大。基于高频交流链接(HF AC link)技术的变换器具有优异的电网侧性能,且不需要大容量的直流储能环节和滤波电抗器,尤其是在...当前大功率直流电源普遍采用直流链接技术和无源功率因数校正方案,电网侧电流谐波较大、功率因数较低且尺寸较大。基于高频交流链接(HF AC link)技术的变换器具有优异的电网侧性能,且不需要大容量的直流储能环节和滤波电抗器,尤其是在大功率电源中有利于减小尺寸,结合串联谐振电路,还可以减小损耗,以满足移动平台对高功率密度、高效率的要求。采用状态平面图法分析了在三相激励条件下的串联谐振电路断续模式下的电流特性,并得到了精确的控制参数表达式,对串联谐振电路采用脉冲密度调制(PDM)的方式调节和稳定直流电源的输出。在对单脉冲电流特性分析基础上给出了基于电网相位进行前馈的控制策略,并构建了前馈和反馈控制相结合的控制系统并对其进行仿真和实验。实验结果与仿真结果一致,表明在负载电阻560Ω上产生28.6k W,即4k V的条件下,电压纹波低于1%,输入侧功率因数为1,各相电流总谐波含量低于5.5%。展开更多
This paper presents the main results on the use of conventional protection hardware to protect a Half Wavelength Transmission Line, or shortly AC-Link, for possible occurrence of three-phase and single-phase fault dur...This paper presents the main results on the use of conventional protection hardware to protect a Half Wavelength Transmission Line, or shortly AC-Link, for possible occurrence of three-phase and single-phase fault during energization maneuver. Lines of these dimensions do not exist today, but in countries of continental size they could be an interesting alternative to HVDC transmission, since the AC-Link has less dependence on Power Electronics technology. The studies on performance and relay settings were implemented using the RTDS real-time simulator. It is important to note that the AC-Link protection for the energization maneuver can be performed with existing hardware on conventional relays.展开更多
基于高频交流链接技术(HF AC-link)的充电电源不仅能够实现常规电源的充电精度,还具有高比功率、内部低储能、输入端低谐波电流、高功率因数的优点;输入端的高性能是AC-link技术追求的目标之一,在控制算法准确的条件下,当前基于高频交...基于高频交流链接技术(HF AC-link)的充电电源不仅能够实现常规电源的充电精度,还具有高比功率、内部低储能、输入端低谐波电流、高功率因数的优点;输入端的高性能是AC-link技术追求的目标之一,在控制算法准确的条件下,当前基于高频交流链接技术的充电电源的输入电流仍有较明显畸变。对工作在高链接频率下基于AC-link技术充电电源的电流畸变现象进行分类,并对畸变原因进行了分析,给出了控制策略和控制算法的改进方案,在平均功率20 k W,峰值电压5 k V充电电源上进行实验,实验结果表明,改善方案将输入电流总谐波含量(THD)由22%降低到7.5%,功率因数由0.97提高到0.99。展开更多
In the present paper the main results of the pre-operational studies related to the energization maneuver of a Half-Wavelength Transmission Line (AC-Link), are presented. The simulations were performed in PSCAD with a...In the present paper the main results of the pre-operational studies related to the energization maneuver of a Half-Wavelength Transmission Line (AC-Link), are presented. The simulations were performed in PSCAD with actual Brazilian system data. Specifically the following studies were performed: electromagnetic transient studies of energization maneuver considering no fault and the occurrence of fault along the trunk;dynamic analysis of generator units that will energize the AC-Link;TRV on the circuit-breaker that will energize the trunk. The main conclusion is that the AC-Link energization experiment can be implemented without jeopardizing or causing time-life reduction of the equipment involved in the experiment, which comprises the generator unit that will energize the trunk, the step-up transformer, the arresters that will be kept during the experiments, as well as the circuit-breaker that will energize and then trip the AC-Link.展开更多
文摘当前大功率直流电源普遍采用直流链接技术和无源功率因数校正方案,电网侧电流谐波较大、功率因数较低且尺寸较大。基于高频交流链接(HF AC link)技术的变换器具有优异的电网侧性能,且不需要大容量的直流储能环节和滤波电抗器,尤其是在大功率电源中有利于减小尺寸,结合串联谐振电路,还可以减小损耗,以满足移动平台对高功率密度、高效率的要求。采用状态平面图法分析了在三相激励条件下的串联谐振电路断续模式下的电流特性,并得到了精确的控制参数表达式,对串联谐振电路采用脉冲密度调制(PDM)的方式调节和稳定直流电源的输出。在对单脉冲电流特性分析基础上给出了基于电网相位进行前馈的控制策略,并构建了前馈和反馈控制相结合的控制系统并对其进行仿真和实验。实验结果与仿真结果一致,表明在负载电阻560Ω上产生28.6k W,即4k V的条件下,电压纹波低于1%,输入侧功率因数为1,各相电流总谐波含量低于5.5%。
文摘This paper presents the main results on the use of conventional protection hardware to protect a Half Wavelength Transmission Line, or shortly AC-Link, for possible occurrence of three-phase and single-phase fault during energization maneuver. Lines of these dimensions do not exist today, but in countries of continental size they could be an interesting alternative to HVDC transmission, since the AC-Link has less dependence on Power Electronics technology. The studies on performance and relay settings were implemented using the RTDS real-time simulator. It is important to note that the AC-Link protection for the energization maneuver can be performed with existing hardware on conventional relays.
文摘基于高频交流链接技术(HF AC-link)的充电电源不仅能够实现常规电源的充电精度,还具有高比功率、内部低储能、输入端低谐波电流、高功率因数的优点;输入端的高性能是AC-link技术追求的目标之一,在控制算法准确的条件下,当前基于高频交流链接技术的充电电源的输入电流仍有较明显畸变。对工作在高链接频率下基于AC-link技术充电电源的电流畸变现象进行分类,并对畸变原因进行了分析,给出了控制策略和控制算法的改进方案,在平均功率20 k W,峰值电压5 k V充电电源上进行实验,实验结果表明,改善方案将输入电流总谐波含量(THD)由22%降低到7.5%,功率因数由0.97提高到0.99。
基金supported CNPq,CAPES and FAPESP in Brazilthe project supported by ELETROBRAS/ELETRONORTE,ELETROBRAS/CHESF and ENTE as part of ANEEL(Brazilian Electrical Energy Regula-tory Agency)strategic project 2008(proc.4500072477).
文摘In the present paper the main results of the pre-operational studies related to the energization maneuver of a Half-Wavelength Transmission Line (AC-Link), are presented. The simulations were performed in PSCAD with actual Brazilian system data. Specifically the following studies were performed: electromagnetic transient studies of energization maneuver considering no fault and the occurrence of fault along the trunk;dynamic analysis of generator units that will energize the AC-Link;TRV on the circuit-breaker that will energize the trunk. The main conclusion is that the AC-Link energization experiment can be implemented without jeopardizing or causing time-life reduction of the equipment involved in the experiment, which comprises the generator unit that will energize the trunk, the step-up transformer, the arresters that will be kept during the experiments, as well as the circuit-breaker that will energize and then trip the AC-Link.
