Virtor(VSG)technology is widely investigated and applied for dual synchronous generatoubly-fed induction generators(DFIGs)to provide virtual inertia.However,under grid faults,the conventional VSG-based DFIG faces chal...Virtor(VSG)technology is widely investigated and applied for dual synchronous generatoubly-fed induction generators(DFIGs)to provide virtual inertia.However,under grid faults,the conventional VSG-based DFIG faces challenges of transient overcurrent and instability.The critical limitation for grid-forming DFIGs to withstand serious grid faults is the rotor-side converter(RSC)’s inability to quickly generate proper rotor voltage to counteract transient electromotive force(EMF),which results in transient overcurrent and damage to the RSC.To fill this gap,this study introduces a novel low-voltage ride-through(LVRT)control strategy for the grid-forming DFIG under symmetrical grid fault conditions.To mitigate transient overcurrent,the core mechanism is to regulate the rotor flux linkage to align with the stator flux linkage in an optimal proportion.Under the proposed control strategy,both post-fault rotor current and required rotor voltage are constrained within operational limits.Moreover,fluctuations in electromagnetic torque are efficiently suppressed during grid disturbances.Consequently,the dynamic stability and power support capacity of the DFIG system remain intact throughout the transient process.Finally,simulation studies and experimental results are provided to verify the feasibility of the proposed approach.展开更多
针对双馈感应发电机(doubly-fed induction generator,DFIG)经电压源变流器–高压直流(voltagesourceconverterhigh voltage direct current,VSC-HVDC)并网,基于"主网频率-直流电压-风电场"串级下垂控制调频策略,建立DFIG经VS...针对双馈感应发电机(doubly-fed induction generator,DFIG)经电压源变流器–高压直流(voltagesourceconverterhigh voltage direct current,VSC-HVDC)并网,基于"主网频率-直流电压-风电场"串级下垂控制调频策略,建立DFIG经VSC-HVDC参与系统一次调频的动态潮流模型,用于量化DFIG备用与直流电容虚拟惯量协同控制下电网频率响应。计及DFIG有功备用,在直流电压限制范围内,提出直流电容虚拟惯性时间常数的取值上限。考虑调频过程中DFIG转速变化,提出基于转子动能的DFIG惯性时间常数动态修正算法,提高动态潮流结果精度。算例验证了所提算法分析DFIG与VSC-HVDC协同电网调频能力的可行性,证实计及DFIG参与调频的直流电容虚拟惯性时间常数最大取值可提升交流系统惯性水平;DFIG等效惯性时间常数修正算法符合其动态调频特性。展开更多
基金supported by the National Natural Science Foundation of China(No.52477195,No.U25B20204,No.52437009).
文摘Virtor(VSG)technology is widely investigated and applied for dual synchronous generatoubly-fed induction generators(DFIGs)to provide virtual inertia.However,under grid faults,the conventional VSG-based DFIG faces challenges of transient overcurrent and instability.The critical limitation for grid-forming DFIGs to withstand serious grid faults is the rotor-side converter(RSC)’s inability to quickly generate proper rotor voltage to counteract transient electromotive force(EMF),which results in transient overcurrent and damage to the RSC.To fill this gap,this study introduces a novel low-voltage ride-through(LVRT)control strategy for the grid-forming DFIG under symmetrical grid fault conditions.To mitigate transient overcurrent,the core mechanism is to regulate the rotor flux linkage to align with the stator flux linkage in an optimal proportion.Under the proposed control strategy,both post-fault rotor current and required rotor voltage are constrained within operational limits.Moreover,fluctuations in electromagnetic torque are efficiently suppressed during grid disturbances.Consequently,the dynamic stability and power support capacity of the DFIG system remain intact throughout the transient process.Finally,simulation studies and experimental results are provided to verify the feasibility of the proposed approach.
文摘针对双馈感应发电机(doubly-fed induction generator,DFIG)经电压源变流器–高压直流(voltagesourceconverterhigh voltage direct current,VSC-HVDC)并网,基于"主网频率-直流电压-风电场"串级下垂控制调频策略,建立DFIG经VSC-HVDC参与系统一次调频的动态潮流模型,用于量化DFIG备用与直流电容虚拟惯量协同控制下电网频率响应。计及DFIG有功备用,在直流电压限制范围内,提出直流电容虚拟惯性时间常数的取值上限。考虑调频过程中DFIG转速变化,提出基于转子动能的DFIG惯性时间常数动态修正算法,提高动态潮流结果精度。算例验证了所提算法分析DFIG与VSC-HVDC协同电网调频能力的可行性,证实计及DFIG参与调频的直流电容虚拟惯性时间常数最大取值可提升交流系统惯性水平;DFIG等效惯性时间常数修正算法符合其动态调频特性。
