This paper presents the operation of LCL type resonant arc welding power supply with fixed frequency and its steady state mathematical model. Using MathCAD to get the results and compared it to the results of the SP...This paper presents the operation of LCL type resonant arc welding power supply with fixed frequency and its steady state mathematical model. Using MathCAD to get the results and compared it to the results of the SPICE simulative experiment, we verify this mathematical model is correct.展开更多
通常风电场位于大电网的末端,并网端口电压的大幅波动将引起锁相环不同程度的暂态响应,使并网系统无法呈现预期的控制性能,甚至出现暂态不稳定的现象。考虑锁相环的暂态特性以及线路参数对大功率直驱风电系统中LCL型并网变换器电流控制...通常风电场位于大电网的末端,并网端口电压的大幅波动将引起锁相环不同程度的暂态响应,使并网系统无法呈现预期的控制性能,甚至出现暂态不稳定的现象。考虑锁相环的暂态特性以及线路参数对大功率直驱风电系统中LCL型并网变换器电流控制性能的影响,提出了一种基于多目标函数的电流环PI控制器参数设计方法。首先,建立了并网电流控制系统的精确静态模型。在此基础上,通过对系统响应特性的幅值裕度、相位裕度和静态误差的分析,得到了满足上述要求的PI控制器参数取值范围。随后,建立了受锁相环性能影响的并网电流控制系统的暂态模型,进一步对已有的PI参数取值区间进行优化,得到了性能更优的控制器参数组合。最后,基于典型参数下1.5 MW的LCL型并网变流器进行了仿真分析,在10 k W的直驱式风力发电并网变流器样机上进行了实验验证。结果表明,该方法可全面改善并网电流控制的动静态响应特性以及对电网环境的适应能力。展开更多
有源阻尼是解决LCL滤波器谐振问题的有效措施,传统的电容电流反馈有源阻尼方法需要增加额外的电流传感器,并网电流反馈有源阻尼存在微分信号提取困难等问题。为此,提出基于线性自抗扰技术(linear active disturbance rejection control,...有源阻尼是解决LCL滤波器谐振问题的有效措施,传统的电容电流反馈有源阻尼方法需要增加额外的电流传感器,并网电流反馈有源阻尼存在微分信号提取困难等问题。为此,提出基于线性自抗扰技术(linear active disturbance rejection control,LADRC)的LCL逆变器并网电流控制及有源阻尼策略。基于LCL滤波器数学模型,设计三阶LADRC并网电流控制器,分析LADRC的跟踪和抗扰能力;将扩张状态观测器(extend state observer,ESO)得到的并网电流微分及二阶微分观测信号作为有源阻尼反馈量,以实现基于并网电流微分反馈的谐振抑制目标,避免了传统直接求取电流微分带来的噪声等问题。仿真和实验结果证明了本文所提策略的有效性。展开更多
Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize acti...Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.展开更多
文摘This paper presents the operation of LCL type resonant arc welding power supply with fixed frequency and its steady state mathematical model. Using MathCAD to get the results and compared it to the results of the SPICE simulative experiment, we verify this mathematical model is correct.
文摘通常风电场位于大电网的末端,并网端口电压的大幅波动将引起锁相环不同程度的暂态响应,使并网系统无法呈现预期的控制性能,甚至出现暂态不稳定的现象。考虑锁相环的暂态特性以及线路参数对大功率直驱风电系统中LCL型并网变换器电流控制性能的影响,提出了一种基于多目标函数的电流环PI控制器参数设计方法。首先,建立了并网电流控制系统的精确静态模型。在此基础上,通过对系统响应特性的幅值裕度、相位裕度和静态误差的分析,得到了满足上述要求的PI控制器参数取值范围。随后,建立了受锁相环性能影响的并网电流控制系统的暂态模型,进一步对已有的PI参数取值区间进行优化,得到了性能更优的控制器参数组合。最后,基于典型参数下1.5 MW的LCL型并网变流器进行了仿真分析,在10 k W的直驱式风力发电并网变流器样机上进行了实验验证。结果表明,该方法可全面改善并网电流控制的动静态响应特性以及对电网环境的适应能力。
文摘有源阻尼是解决LCL滤波器谐振问题的有效措施,传统的电容电流反馈有源阻尼方法需要增加额外的电流传感器,并网电流反馈有源阻尼存在微分信号提取困难等问题。为此,提出基于线性自抗扰技术(linear active disturbance rejection control,LADRC)的LCL逆变器并网电流控制及有源阻尼策略。基于LCL滤波器数学模型,设计三阶LADRC并网电流控制器,分析LADRC的跟踪和抗扰能力;将扩张状态观测器(extend state observer,ESO)得到的并网电流微分及二阶微分观测信号作为有源阻尼反馈量,以实现基于并网电流微分反馈的谐振抑制目标,避免了传统直接求取电流微分带来的噪声等问题。仿真和实验结果证明了本文所提策略的有效性。
文摘Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.
