To achieve the goal of carbon neutrality,renewable energy integration through a voltage source converter based multi-terminal direct current(VSC-MTDC)system has been identified as a promising solution.To tackle the si...To achieve the goal of carbon neutrality,renewable energy integration through a voltage source converter based multi-terminal direct current(VSC-MTDC)system has been identified as a promising solution.To tackle the significant DC voltage over-limit problem in a VSC-MTDC system during disturbances,this paper proposes a mode-switching strategy of droop control considering maximum DC voltage regulation capability.The close relationship between node injection powers and node DC voltages in the MTDC system is elaborated,and the most effective regulation approach of local injection power for limiting DC voltage deviation is presented.The operating point trajectories of different droop control explains that the DC voltage deviation can be minimized by fully utilizing the capacity of converters.Therefore,the mode-switching strategy with the maximum DC voltage regulation capability is realized by the switching between the voltage droop control and the constant maximum power control.In addition,a mode recovery process and a smooth switching method are developed to make converters regain the capability of maintaining DC voltage and reduce power fluctuation during mode switching,respectively.Furthermore,three cases are investigated to verify the effectiveness of the proposed mode-switching strategy.Compared with simulation results of the conventional droop control and the DC voltage deviation-dependent droop control,better performance of transient and steady-state DC voltage deviation is achieved through the proposed strategy.展开更多
可控串联补偿(thyristor controlled series capacitor,TCSC)的模式切换对电力系统的稳定控制具有重要意义。TCSC阻抗双解现象的存在对其模式切换提出了更高的要求,单一改变触发角的方法无法实现模式切换。在考虑阻抗双解现象影响的基础...可控串联补偿(thyristor controlled series capacitor,TCSC)的模式切换对电力系统的稳定控制具有重要意义。TCSC阻抗双解现象的存在对其模式切换提出了更高的要求,单一改变触发角的方法无法实现模式切换。在考虑阻抗双解现象影响的基础上,提出了一套相应的TCSC模式切换控制方法。通过强制晶闸管支路电流与线路电流同步,实现由容性区到Bypass模式的切换;在由容性区到感性微调模式切换的过程中提出了晶闸管条件触发的方法,即当线路电流和电容电压满足同向条件时晶闸管才触发导通。同时为及时向切换控制提供线路电流同步信号,提出了一种预测电流过零的新方法。数字仿真及动模实验结果表明,提出的切换方法能使切换过程平稳迅速,且动态特性良好。展开更多
As a new drive system for electric vehicles,the dual-mode coupling drive system can automatically switch between centralized and distributed drive modes and realize two-speed gear shifting.Because the actuator’s disp...As a new drive system for electric vehicles,the dual-mode coupling drive system can automatically switch between centralized and distributed drive modes and realize two-speed gear shifting.Because the actuator’s displacement signal affects the mode-switching control,when failure occurs at the angle-displacement sensor,the mode-shifting quality is likely to drop greatly,even possibly leading to shift failure.To address the angle-displacement sensor failure and improve the reliability of the shift control,an adaptive fault-tolerant control method is proposed and verified.First,the effect of the output signal of the angle-displacement sensor in the mode-switching control process is analyzed.Then,an adaptive mode-switching fault-tolerant control method is designed based on the Kalman filter and fuzzy theory.Finally,the feasibility of the control effect is verified through simulations and vehicle experiments.The results indicate that the proposed method can effectively eliminate the signal noise of the angle-displacement sensor and successfully switch the modes when the sensor fails.It provides a reference for ensuring the working quality of similar electric drive systems under sensor failures.展开更多
为满足直流微电网内各电源协调运行的需要,本文提出了一种新的切换策略,使光伏控制器能够在最大功率跟踪(maximum power point tracking,MPPT)和恒压控制(constant voltage control,CVC)模式之间平稳地运行。在这两种模式下,光伏控制器...为满足直流微电网内各电源协调运行的需要,本文提出了一种新的切换策略,使光伏控制器能够在最大功率跟踪(maximum power point tracking,MPPT)和恒压控制(constant voltage control,CVC)模式之间平稳地运行。在这两种模式下,光伏控制器始终作为电压源被控制,其控制变量均为光伏阵列的输出电压。该方法将MPPT与母线电压调整策略相结合,无需通信,无需改变硬件结构和控制参数,从而保证了光伏控制器在两种模式之间的无缝切换。最后,建立了一个由光伏机组、直流负载和储能组成的基本直流组网系统,对所提出的控制策略进行性能测试。结果表明,与传统控制策略相比,所提出的无缝切换控制策略获得了更好的暂态特性。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 52377119 and U22B20109.
文摘To achieve the goal of carbon neutrality,renewable energy integration through a voltage source converter based multi-terminal direct current(VSC-MTDC)system has been identified as a promising solution.To tackle the significant DC voltage over-limit problem in a VSC-MTDC system during disturbances,this paper proposes a mode-switching strategy of droop control considering maximum DC voltage regulation capability.The close relationship between node injection powers and node DC voltages in the MTDC system is elaborated,and the most effective regulation approach of local injection power for limiting DC voltage deviation is presented.The operating point trajectories of different droop control explains that the DC voltage deviation can be minimized by fully utilizing the capacity of converters.Therefore,the mode-switching strategy with the maximum DC voltage regulation capability is realized by the switching between the voltage droop control and the constant maximum power control.In addition,a mode recovery process and a smooth switching method are developed to make converters regain the capability of maintaining DC voltage and reduce power fluctuation during mode switching,respectively.Furthermore,three cases are investigated to verify the effectiveness of the proposed mode-switching strategy.Compared with simulation results of the conventional droop control and the DC voltage deviation-dependent droop control,better performance of transient and steady-state DC voltage deviation is achieved through the proposed strategy.
文摘可控串联补偿(thyristor controlled series capacitor,TCSC)的模式切换对电力系统的稳定控制具有重要意义。TCSC阻抗双解现象的存在对其模式切换提出了更高的要求,单一改变触发角的方法无法实现模式切换。在考虑阻抗双解现象影响的基础上,提出了一套相应的TCSC模式切换控制方法。通过强制晶闸管支路电流与线路电流同步,实现由容性区到Bypass模式的切换;在由容性区到感性微调模式切换的过程中提出了晶闸管条件触发的方法,即当线路电流和电容电压满足同向条件时晶闸管才触发导通。同时为及时向切换控制提供线路电流同步信号,提出了一种预测电流过零的新方法。数字仿真及动模实验结果表明,提出的切换方法能使切换过程平稳迅速,且动态特性良好。
基金This study was supported by the National Natural Science Foundation of China(Grant No.51775478)Natural Science Foundation of Hebei Province of China(Grant Nos:E2016203173,E2020203078,E2020203174).
文摘As a new drive system for electric vehicles,the dual-mode coupling drive system can automatically switch between centralized and distributed drive modes and realize two-speed gear shifting.Because the actuator’s displacement signal affects the mode-switching control,when failure occurs at the angle-displacement sensor,the mode-shifting quality is likely to drop greatly,even possibly leading to shift failure.To address the angle-displacement sensor failure and improve the reliability of the shift control,an adaptive fault-tolerant control method is proposed and verified.First,the effect of the output signal of the angle-displacement sensor in the mode-switching control process is analyzed.Then,an adaptive mode-switching fault-tolerant control method is designed based on the Kalman filter and fuzzy theory.Finally,the feasibility of the control effect is verified through simulations and vehicle experiments.The results indicate that the proposed method can effectively eliminate the signal noise of the angle-displacement sensor and successfully switch the modes when the sensor fails.It provides a reference for ensuring the working quality of similar electric drive systems under sensor failures.
文摘为满足直流微电网内各电源协调运行的需要,本文提出了一种新的切换策略,使光伏控制器能够在最大功率跟踪(maximum power point tracking,MPPT)和恒压控制(constant voltage control,CVC)模式之间平稳地运行。在这两种模式下,光伏控制器始终作为电压源被控制,其控制变量均为光伏阵列的输出电压。该方法将MPPT与母线电压调整策略相结合,无需通信,无需改变硬件结构和控制参数,从而保证了光伏控制器在两种模式之间的无缝切换。最后,建立了一个由光伏机组、直流负载和储能组成的基本直流组网系统,对所提出的控制策略进行性能测试。结果表明,与传统控制策略相比,所提出的无缝切换控制策略获得了更好的暂态特性。
