The DC microgrid has the advantages of high energy conversion efficiency,high energy transmission density,no reactive power flow,and grid-connected synchronization.It is an essential component of the future intelligen...The DC microgrid has the advantages of high energy conversion efficiency,high energy transmission density,no reactive power flow,and grid-connected synchronization.It is an essential component of the future intelligent power distribution system.Constant power load(CPL)will degrade the stability of the DC microgrid and cause system voltage oscillation due to its negative resistance characteristics.As a result,the stability of DC microgrids with CPL has become a problem.At present,the research on the stability of DC microgrid is mainly focused on unipolar DC microgrid,while the research on bipolar DC microgrid lacks systematic discussion.The stability of DC microgrid using CPL was studied first,and then the current stability criteria of DC microgrid were summarized,and its research trend was analyzed.On this basis,aiming at the stability problem caused by CPL,the existing control methods were summarized from the perspective of source converter output impedance and load converter input impedance,and the current control methods were outlined as active and passive control methods.Lastly,the research path of bipolar DC microgrid stability with CPL was prospected.展开更多
The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the ...The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. A PWM-based current-sensorless robust sliding mode controller is developed that requires only the measurement of the output voltage. An extended state observer is developed to estimate a lumped uncertainty signal that comprises the uncertain load power and the input voltage, the converter parasitics, the component uncertainties and the estimation of the derivative of the output voltage needed in the implementation of the controller. A linear sliding surface is used to derive the controller, which is simple in its design and yet exhibits excellent features in terms of robustness to external disturbances, parameter uncertainties, and parasitics despite the absence of the inductor’s current feedback. The robustness of the controller is validated by computer simulations.展开更多
The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the ...The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. In this work, a robust nonlinear controller based on the uncertainty and disturbance estimator (UDE) scheme is successfully developed to tightly regulate the output voltage of the boost converter. A systematic procedure is developed to select the controller gains to achieve a satisfactory output response. Using simulation, the effectiveness of the proposed controller is validated and compared to a recent robust nonlinear controller.展开更多
为解决船舶微电网源-荷级联系统中LC输入滤波器与恒功率负载CPL(constant power load)引起的母线电压振荡问题,提出一种基于非线性扰动观测器NDO(nonlinear disturbance observer)的虚拟负电感有源阻尼稳定控制策略。首先分析了恒功率...为解决船舶微电网源-荷级联系统中LC输入滤波器与恒功率负载CPL(constant power load)引起的母线电压振荡问题,提出一种基于非线性扰动观测器NDO(nonlinear disturbance observer)的虚拟负电感有源阻尼稳定控制策略。首先分析了恒功率负载的负阻抗特性及其能量反馈作用,深入研究了源-荷级联系统低阻尼振荡的机理;详细推导了级联系统的稳定约束条件,进而提出适用于源侧变换器的有源阻尼稳定策略,建立了级联系统小信号阻抗模型,利用奈奎斯特判据进行了稳定性分析。利用非线性扰动观测器摆脱了控制算法对输出电流传感器较强的依赖性,抵消了负阻抗特性对系统稳定性造成的不利影响。最后,通过仿真验证所提控制算法的有效性,并对稳定性分析部分进行了实例论证。展开更多
在多变换器电力电子系统中,负载变换器可以等效为前级变换器的恒定功率负载CPL(constant power load),这给系统带来了等效负电阻,导致系统不稳定,而采用主动阻尼的方法能够解决这个问题,并且不产生额外功耗,故根据主动阻尼方法改进了Buc...在多变换器电力电子系统中,负载变换器可以等效为前级变换器的恒定功率负载CPL(constant power load),这给系统带来了等效负电阻,导致系统不稳定,而采用主动阻尼的方法能够解决这个问题,并且不产生额外功耗,故根据主动阻尼方法改进了Buck DC/DC开关变换器。展开更多
基金supported by National Natural Science Foundation of China(No.51767015)Key Project of Natural Science Foundation of Gansu Province(No.22JR5RA317)Tianyou Innovation Team Support Program of Lanzhou Jiaotong University(No.TY202009)。
文摘The DC microgrid has the advantages of high energy conversion efficiency,high energy transmission density,no reactive power flow,and grid-connected synchronization.It is an essential component of the future intelligent power distribution system.Constant power load(CPL)will degrade the stability of the DC microgrid and cause system voltage oscillation due to its negative resistance characteristics.As a result,the stability of DC microgrids with CPL has become a problem.At present,the research on the stability of DC microgrid is mainly focused on unipolar DC microgrid,while the research on bipolar DC microgrid lacks systematic discussion.The stability of DC microgrid using CPL was studied first,and then the current stability criteria of DC microgrid were summarized,and its research trend was analyzed.On this basis,aiming at the stability problem caused by CPL,the existing control methods were summarized from the perspective of source converter output impedance and load converter input impedance,and the current control methods were outlined as active and passive control methods.Lastly,the research path of bipolar DC microgrid stability with CPL was prospected.
文摘The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. A PWM-based current-sensorless robust sliding mode controller is developed that requires only the measurement of the output voltage. An extended state observer is developed to estimate a lumped uncertainty signal that comprises the uncertain load power and the input voltage, the converter parasitics, the component uncertainties and the estimation of the derivative of the output voltage needed in the implementation of the controller. A linear sliding surface is used to derive the controller, which is simple in its design and yet exhibits excellent features in terms of robustness to external disturbances, parameter uncertainties, and parasitics despite the absence of the inductor’s current feedback. The robustness of the controller is validated by computer simulations.
文摘The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. In this work, a robust nonlinear controller based on the uncertainty and disturbance estimator (UDE) scheme is successfully developed to tightly regulate the output voltage of the boost converter. A systematic procedure is developed to select the controller gains to achieve a satisfactory output response. Using simulation, the effectiveness of the proposed controller is validated and compared to a recent robust nonlinear controller.
文摘为解决船舶微电网源-荷级联系统中LC输入滤波器与恒功率负载CPL(constant power load)引起的母线电压振荡问题,提出一种基于非线性扰动观测器NDO(nonlinear disturbance observer)的虚拟负电感有源阻尼稳定控制策略。首先分析了恒功率负载的负阻抗特性及其能量反馈作用,深入研究了源-荷级联系统低阻尼振荡的机理;详细推导了级联系统的稳定约束条件,进而提出适用于源侧变换器的有源阻尼稳定策略,建立了级联系统小信号阻抗模型,利用奈奎斯特判据进行了稳定性分析。利用非线性扰动观测器摆脱了控制算法对输出电流传感器较强的依赖性,抵消了负阻抗特性对系统稳定性造成的不利影响。最后,通过仿真验证所提控制算法的有效性,并对稳定性分析部分进行了实例论证。
