To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier emp...To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.展开更多
This paper proposes a dual vector control scheme based on the sequence component separation strategy(SCSS)for second harmonic suppression in DC power.Firstly,an analytical model is established to depict the positive a...This paper proposes a dual vector control scheme based on the sequence component separation strategy(SCSS)for second harmonic suppression in DC power.Firstly,an analytical model is established to depict the positive and negative sequences of the controllable current source converter(CSC)under unbalanced grid conditions.Moreover,the generation mechanism of the DC power second harmonic component in the hybrid VSC-CSC HVDC system is demonstrated.This paper summarizes the impact of the modulation index(MI)and power factor(PF)on the operating characteristics of the modular multilevel converter(MMC)during the variation of the DC voltage.Based on the above analysis,the proposed control scheme extracts the sequence components of the CSC capacitor voltage and directly computes the sequence voltage reference value using instantaneous power.This approach effectively suppresses the second-harmonic component in DC power and significantly reduces the range of capacitor-voltage fluctuations in MMC submodules.Finally,an electromagnetic transient model of the hybrid HVDC system is constructed to validate the accuracy of the theoretical analysis and the effectiveness of the proposed control scheme.展开更多
将二极管整流单元(diode rectifier unit,DRU)与模块化多电平变换器(modular multilevel converter,MMC)背靠背连接组成交-交变流器并应用于低频交流(low frequency alternative current,LFAC)输电系统中,是降低海上风电送出成本的重要...将二极管整流单元(diode rectifier unit,DRU)与模块化多电平变换器(modular multilevel converter,MMC)背靠背连接组成交-交变流器并应用于低频交流(low frequency alternative current,LFAC)输电系统中,是降低海上风电送出成本的重要技术路线之一。针对该系统中谐波含量过高的问题,提出了一种低成本谐波抑制方法。首先,对DRU-LFAC系统的谐波特性进行了分析,并在此基础上提出一种新型交流侧电流谐波抑制策略。所提策略通过在正负极直流线路中注入特定的电流谐波以实现对交流侧电流谐波的抑制。同时,直流侧谐波电流的通路由双极性背靠背DRU-MMC的中性线提供。随后,对所提策略产生的额外运行损耗进行了定量计算,并与常规滤波方法进行了经济性对比分析;最后,通过PSCAD/EMTDC仿真和远宽StarSim控制器硬件在环实验验证了所提谐波抑制策略的有效性。研究结果表明:所提策略相较于常规滤波方法在海上风电工程的整个生命周期内能降低约70%的滤波成本,且能够有效降低系统交流侧电流的总谐波失真(total harmonic distortion,THD)。展开更多
To address harmonic current proliferation and parameter sensitivity in conventional vector model predictive control(V-MPC)for dual-three-phase permanent magnet synchronous generators(DTP-PMSGs),a harmonic subspace-inc...To address harmonic current proliferation and parameter sensitivity in conventional vector model predictive control(V-MPC)for dual-three-phase permanent magnet synchronous generators(DTP-PMSGs),a harmonic subspace-incorporated disturbance-rejection MPC strategy is proposed.First,an enhanced virtual voltage vector synthesis technique is developed in which three optimal voltage vectors per control sector are strategically combined to achieve full-amplitude and omnidirectional voltage coverage,eliminating harmonic subspace excitation.Second,a super-twisting integral disturbance observer is designed to dynamically estimate and compensate for parameter mismatches and nonlinear rectification disturbances,thereby enhancing the robustness against model inaccuracies.Third,a composite harmonic suppression controller is proposed to replace traditional PI regulators,enabling zero-steady-state error tracking of fundamental currents while actively attenuating harmonic subspace components.Experimental validations confirm that the proposed methodology improves the fundamental current-tracking accuracy,significantly suppresses harmonic currents,and maintains a robust dynamic response under parameter variations.展开更多
为提高电网频率波动条件下并联型有源电力滤波器(shunt active power filters,SAPF)的补偿电流跟踪控制精度,有效抑制电网的谐波污染,提出一种具有变频适应性的重复控制策略。采用可调整采样频率的选择性重复控制器构建多采样率重复控...为提高电网频率波动条件下并联型有源电力滤波器(shunt active power filters,SAPF)的补偿电流跟踪控制精度,有效抑制电网的谐波污染,提出一种具有变频适应性的重复控制策略。采用可调整采样频率的选择性重复控制器构建多采样率重复控制系统,利用基于拉格朗日线性插值法的有限脉冲响应(FIR)滤波器将多采样率重复控制系统转换成具有统一采样频率的重复控制系统(frequency-adaptive uniform-rate selective repetitive control system,FUSRCS),通过跟随电网频率调整重复控制器延迟环节近似表达式系数的方法使FUSRCS能适应电网频率波动,设计了FUSRCS的补偿器,分析了FUSRCS的稳定性、收敛性和稳态误差,建立了三相SAPF的数学模型,依据实际数据设计了基于FUSRCS的补偿电流复合重复控制系统。仿真和实验结果表明:基于FUSRCS的SAPF能够在电网频率存在稳态偏差、电网频率动态变化和负载切换等情况下,保持较高的补偿电流跟踪精度和较好的补偿效果。与经典重复控制相比,FUSRCS在具有变频适应性的同时,减少了控制系统的计算负担,提高了系统的动态响应速度,解决了多采样率重复控制系统带来的问题。展开更多
交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种...交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种注入多谐波电流产生的转矩补偿原有转矩脉动的控制策略。推导适用于任意次谐波磁链产生的转矩脉动通用解析模型;并基于此模型,给出利用谐波电流抑制转矩脉动的理论依据;提出在同步旋转坐标系下注入多次谐波电流的方法,抑制由2、4、5、7、11、13次谐波反电势引起的3、6、12次转矩脉动;并利用准-比例谐振控制器实现谐波电流的精确跟踪。最后,以一台三相9槽10极交替极永磁电机为例,通过不同工况下的转矩脉动抑制实验,验证所提控制策略的有效性。展开更多
基金Natural Science Foundation of Gansu Province Education Department(No.2017A-020)National Natural Science Foundation of China(No.51767013)Science and Technology Research and Development Plan of China Railway Corporation(No.2017J012-A)
文摘To solve the input current harmonic pollution of the high power rectifier system,18-pulse rectifier based on a kind of active harmonic suppression technique at dc side is proposed in this paper.The pulse rectifier employs three-phase diode bridges,each of them followed by a boost converter.Unlike the conventional three-phase unity-power-factor diode rectifier,the ideal sinusoidal main currents of circuit topology are obtained by control its output current or input currents of three boost converters for approximately triangular modulation.The theoretical of modulation strategy and characteristics of input and output currents about the proposed rectifier are analyzed in detail.Simulation results by Matlab/Simulink demonstrate that the proposed rectifier draws nearly sinusoidal current and power quality index is improved.The correctness of the theoretical analysis is validated.
基金supported by Smart GridNational Science and Technology Major Project(2025ZD0803700).
文摘This paper proposes a dual vector control scheme based on the sequence component separation strategy(SCSS)for second harmonic suppression in DC power.Firstly,an analytical model is established to depict the positive and negative sequences of the controllable current source converter(CSC)under unbalanced grid conditions.Moreover,the generation mechanism of the DC power second harmonic component in the hybrid VSC-CSC HVDC system is demonstrated.This paper summarizes the impact of the modulation index(MI)and power factor(PF)on the operating characteristics of the modular multilevel converter(MMC)during the variation of the DC voltage.Based on the above analysis,the proposed control scheme extracts the sequence components of the CSC capacitor voltage and directly computes the sequence voltage reference value using instantaneous power.This approach effectively suppresses the second-harmonic component in DC power and significantly reduces the range of capacitor-voltage fluctuations in MMC submodules.Finally,an electromagnetic transient model of the hybrid HVDC system is constructed to validate the accuracy of the theoretical analysis and the effectiveness of the proposed control scheme.
文摘将二极管整流单元(diode rectifier unit,DRU)与模块化多电平变换器(modular multilevel converter,MMC)背靠背连接组成交-交变流器并应用于低频交流(low frequency alternative current,LFAC)输电系统中,是降低海上风电送出成本的重要技术路线之一。针对该系统中谐波含量过高的问题,提出了一种低成本谐波抑制方法。首先,对DRU-LFAC系统的谐波特性进行了分析,并在此基础上提出一种新型交流侧电流谐波抑制策略。所提策略通过在正负极直流线路中注入特定的电流谐波以实现对交流侧电流谐波的抑制。同时,直流侧谐波电流的通路由双极性背靠背DRU-MMC的中性线提供。随后,对所提策略产生的额外运行损耗进行了定量计算,并与常规滤波方法进行了经济性对比分析;最后,通过PSCAD/EMTDC仿真和远宽StarSim控制器硬件在环实验验证了所提谐波抑制策略的有效性。研究结果表明:所提策略相较于常规滤波方法在海上风电工程的整个生命周期内能降低约70%的滤波成本,且能够有效降低系统交流侧电流的总谐波失真(total harmonic distortion,THD)。
基金Supported by National Science Fund for Distinguished Young Scholars(52023073).
文摘To address harmonic current proliferation and parameter sensitivity in conventional vector model predictive control(V-MPC)for dual-three-phase permanent magnet synchronous generators(DTP-PMSGs),a harmonic subspace-incorporated disturbance-rejection MPC strategy is proposed.First,an enhanced virtual voltage vector synthesis technique is developed in which three optimal voltage vectors per control sector are strategically combined to achieve full-amplitude and omnidirectional voltage coverage,eliminating harmonic subspace excitation.Second,a super-twisting integral disturbance observer is designed to dynamically estimate and compensate for parameter mismatches and nonlinear rectification disturbances,thereby enhancing the robustness against model inaccuracies.Third,a composite harmonic suppression controller is proposed to replace traditional PI regulators,enabling zero-steady-state error tracking of fundamental currents while actively attenuating harmonic subspace components.Experimental validations confirm that the proposed methodology improves the fundamental current-tracking accuracy,significantly suppresses harmonic currents,and maintains a robust dynamic response under parameter variations.
文摘为提高电网频率波动条件下并联型有源电力滤波器(shunt active power filters,SAPF)的补偿电流跟踪控制精度,有效抑制电网的谐波污染,提出一种具有变频适应性的重复控制策略。采用可调整采样频率的选择性重复控制器构建多采样率重复控制系统,利用基于拉格朗日线性插值法的有限脉冲响应(FIR)滤波器将多采样率重复控制系统转换成具有统一采样频率的重复控制系统(frequency-adaptive uniform-rate selective repetitive control system,FUSRCS),通过跟随电网频率调整重复控制器延迟环节近似表达式系数的方法使FUSRCS能适应电网频率波动,设计了FUSRCS的补偿器,分析了FUSRCS的稳定性、收敛性和稳态误差,建立了三相SAPF的数学模型,依据实际数据设计了基于FUSRCS的补偿电流复合重复控制系统。仿真和实验结果表明:基于FUSRCS的SAPF能够在电网频率存在稳态偏差、电网频率动态变化和负载切换等情况下,保持较高的补偿电流跟踪精度和较好的补偿效果。与经典重复控制相比,FUSRCS在具有变频适应性的同时,减少了控制系统的计算负担,提高了系统的动态响应速度,解决了多采样率重复控制系统带来的问题。
文摘交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种注入多谐波电流产生的转矩补偿原有转矩脉动的控制策略。推导适用于任意次谐波磁链产生的转矩脉动通用解析模型;并基于此模型,给出利用谐波电流抑制转矩脉动的理论依据;提出在同步旋转坐标系下注入多次谐波电流的方法,抑制由2、4、5、7、11、13次谐波反电势引起的3、6、12次转矩脉动;并利用准-比例谐振控制器实现谐波电流的精确跟踪。最后,以一台三相9槽10极交替极永磁电机为例,通过不同工况下的转矩脉动抑制实验,验证所提控制策略的有效性。
