The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, re...The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.展开更多
光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下...光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下的换流器运行小信号阻抗模型。其次,利用阻抗比判据对比分析系统稳定性差异,并讨论了不同虚拟电阻对系统稳定性的影响。最后,通过将产生谐振峰值处的角频率点与其相邻正常角频率点的等效阻抗幅值之比限定为[0.95,1.15],将阻尼电阻值在最大功率点跟踪(maximum power point tracking,MPPT)控制下换流器的闭环输出阻抗幅值提高了约1.5倍。研究结果表明,相比仅采用有源或无源阻尼法,所提协同控制策略使得产生谐振处的幅值由–15 dB增加到40.5 dB,提高约4倍,且系统具有较大的幅值和相角裕度,可有效提高系统的稳定性。展开更多
风电机组经串、并联补偿并网可以降低线损,并有效提高线路送电功率和系统运行的稳定性,但补偿电容与风电机组控制装置之间的相互作用可能会引发包括次同步谐振和高频谐振的宽频域谐振稳定性问题。考虑串补、并补两种并网线路类型推导并...风电机组经串、并联补偿并网可以降低线损,并有效提高线路送电功率和系统运行的稳定性,但补偿电容与风电机组控制装置之间的相互作用可能会引发包括次同步谐振和高频谐振的宽频域谐振稳定性问题。考虑串补、并补两种并网线路类型推导并建立了双馈风机并网系统的阻抗模型,利用阻抗法分析风机并网系统宽频域谐振的发生机理提出并设计了一个自适应宽频域谐振抑制器,将其并联连接到公共耦合点(point of common coupling,PCC),通过提取PCC点谐振电压并利用谐波含量限制的方法合成一个阻尼电阻以抑制系统产生的宽频域谐振。最后在MATLAB/Simulink中搭建了风电并网系统等值系统模型,通过时域仿真验证了该自适应宽频域谐振控制器的正确性和有效性。展开更多
基金Project(61104088)supported by the National Natural Science Foundation of ChinaProject(12C0741)supported by Scientific Research Fund of Hunan Provincial Education Department,China
文摘The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.
文摘光伏直流升压汇集系统中,DC/DC换流器内部LC电路与开关电路因阻抗匹配而产生谐振问题,从而导致系统稳定性变差甚至崩溃。针对换流器因阻抗匹配产生的谐振问题,提出了有源和无源阻尼协同控制以消除谐振的方法。首先,建立了在不同工况下的换流器运行小信号阻抗模型。其次,利用阻抗比判据对比分析系统稳定性差异,并讨论了不同虚拟电阻对系统稳定性的影响。最后,通过将产生谐振峰值处的角频率点与其相邻正常角频率点的等效阻抗幅值之比限定为[0.95,1.15],将阻尼电阻值在最大功率点跟踪(maximum power point tracking,MPPT)控制下换流器的闭环输出阻抗幅值提高了约1.5倍。研究结果表明,相比仅采用有源或无源阻尼法,所提协同控制策略使得产生谐振处的幅值由–15 dB增加到40.5 dB,提高约4倍,且系统具有较大的幅值和相角裕度,可有效提高系统的稳定性。
文摘风电机组经串、并联补偿并网可以降低线损,并有效提高线路送电功率和系统运行的稳定性,但补偿电容与风电机组控制装置之间的相互作用可能会引发包括次同步谐振和高频谐振的宽频域谐振稳定性问题。考虑串补、并补两种并网线路类型推导并建立了双馈风机并网系统的阻抗模型,利用阻抗法分析风机并网系统宽频域谐振的发生机理提出并设计了一个自适应宽频域谐振抑制器,将其并联连接到公共耦合点(point of common coupling,PCC),通过提取PCC点谐振电压并利用谐波含量限制的方法合成一个阻尼电阻以抑制系统产生的宽频域谐振。最后在MATLAB/Simulink中搭建了风电并网系统等值系统模型,通过时域仿真验证了该自适应宽频域谐振控制器的正确性和有效性。
