The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/D...The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation.展开更多
China Southern Power Grid is a unique EHV AC/DC hybrid transmission network that operates in China. In its service area, the distribution of energy resources and the development of economy are extremely unbalanced, so...China Southern Power Grid is a unique EHV AC/DC hybrid transmission network that operates in China. In its service area, the distribution of energy resources and the development of economy are extremely unbalanced, so long-distance and bulk power transmission are needed; besides, the geography and climate conditions are serious, rains, fogs, lightning and typhoon as well as high temperature are common all the year round. Facing these challenges, the power grid enhanced stability control, improved the equipment and strengthen the network structure. In the future, the power grid plans to optimize the disposition of power sources and build digitalized power system.展开更多
针对风电和光伏并网发电系统的功率波动问题,研究了一种基于双向DC/AC变换器的混合储能系统的动态控制策略。对含有超级电容器与蓄电池组的混合储能系统,通过双闭环控制器对变换器内部的电压电流进行控制,把波动变化较快的电流分量分配...针对风电和光伏并网发电系统的功率波动问题,研究了一种基于双向DC/AC变换器的混合储能系统的动态控制策略。对含有超级电容器与蓄电池组的混合储能系统,通过双闭环控制器对变换器内部的电压电流进行控制,把波动变化较快的电流分量分配给超级电容器,由蓄电池来响应波动变化较慢的电流分量。同时,控制系统将超级电容器的电压稳定在预设范围内。基于扩展卡尔曼滤波(Extended Kalman Filter,EKF)对蓄电池的荷电状态(State of Charge,SOC)进行控制,使其SOC值稳定在安全范围内并延长了蓄电池的使用寿命。通过仿真实验,验证了控制方法的有效性。展开更多
针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不...针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不确定因素的快速追踪与补偿,保证了在不同扰动下交直流混合微电网的稳定性。进一步提出了基于NLESO的改进积分滑模控制方法,提高了直流母线电压的控制精度。结合非线性光滑函数设计了滑模趋近律,消除了传统滑模控制中的高频抖振现象。通过Lyapunov理论对系统的稳定性进行分析验证,仿真结果表明该控制方法响应速度快、控制精度高、抗扰动能力强并且无抖振现象。展开更多
This paper presents performance analysis on hybrid AC/DC microgrid networks for residential home cluster. The design of the proposed microgrid includes comprehensive types of Distributed Generators (DGs) as hybrid pow...This paper presents performance analysis on hybrid AC/DC microgrid networks for residential home cluster. The design of the proposed microgrid includes comprehensive types of Distributed Generators (DGs) as hybrid power sources (wind, Photovoltaic (PV) solar cell, battery, fuel cell). Details about each DG dynamic modeling are presented and discussed. The customers in home cluster can be connected in both of the operating modes: islanded to the microgrid or connected to utility grid. Each DG has appended control system with its modeling that will be discussed to control DG performance. The wind turbine will be controlled by AC control system within three sub-control systems: 1) speed regulator and pitch control, 2) rotor side converter control, and 3) grid side converter control. The AC control structure is based on PLL, current regulator and voltage booster converter with using of photovoltaic Voltage Source Converter (VSC) and inverters to connect to the grid. The DC control system is mainly based on Maximum Power Point Tracking (MPPT) controller and boost converter connected to the PV array block and in order to control the system. The case study is used to analyze the performance of the proposed microgrid. The buses voltages, active power and reactive power responses are presented in both of grid-connected and islanded modes. In addition, the power factor, Total Harmonic Distortion (THD) and modulation index are calculated.展开更多
为提高风电场交直流混合输电并网的系统性能,提出一种更加灵活的电压源换流器高压直流(voltage source converter based high voltage direct current,VSC-HVDC)控制策略。对于风电场侧电压源换流器,设计了一种新的交流电压–功角控制...为提高风电场交直流混合输电并网的系统性能,提出一种更加灵活的电压源换流器高压直流(voltage source converter based high voltage direct current,VSC-HVDC)控制策略。对于风电场侧电压源换流器,设计了一种新的交流电压–功角控制方法。对于交直流混合输电模式,该方法通过调节风电场交流母线电压与电压源换流器输出电压间的功角来实现定有功功率控制。对于纯柔性直流输电模式,风电场交流母线电压自动被调节为具有恒幅恒频的交流电压,实现了对波动风电的同步输送。该方法中输电模式的变化无需切换控制;另外,通过附加电流高通滤波器增强了对系统谐振的阻尼作用。对电网侧电压源换流器,采用一种新的直接电流矢量控制,使直流电压稳定在参考值上。运用PSCAD/EMTDC仿真软件对分别接入笼型感应发电机(squirrel cage induction generator,SCIG)风电场和双馈感应发电机(doubly fed induction generator,DFIG)风电场的交直流混合输电系统建模仿真。一系列运行条件下的仿真结果验证了控制方法的有效性与可行性。展开更多
基金supported by National Key Research and Development Program of China (2016YFB0900500,2017YFB0903100)the State Grid Science and Technology Project (SGRI-DL-F1-51-011)
文摘The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation.
文摘China Southern Power Grid is a unique EHV AC/DC hybrid transmission network that operates in China. In its service area, the distribution of energy resources and the development of economy are extremely unbalanced, so long-distance and bulk power transmission are needed; besides, the geography and climate conditions are serious, rains, fogs, lightning and typhoon as well as high temperature are common all the year round. Facing these challenges, the power grid enhanced stability control, improved the equipment and strengthen the network structure. In the future, the power grid plans to optimize the disposition of power sources and build digitalized power system.
文摘针对风电和光伏并网发电系统的功率波动问题,研究了一种基于双向DC/AC变换器的混合储能系统的动态控制策略。对含有超级电容器与蓄电池组的混合储能系统,通过双闭环控制器对变换器内部的电压电流进行控制,把波动变化较快的电流分量分配给超级电容器,由蓄电池来响应波动变化较慢的电流分量。同时,控制系统将超级电容器的电压稳定在预设范围内。基于扩展卡尔曼滤波(Extended Kalman Filter,EKF)对蓄电池的荷电状态(State of Charge,SOC)进行控制,使其SOC值稳定在安全范围内并延长了蓄电池的使用寿命。通过仿真实验,验证了控制方法的有效性。
文摘针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不确定因素的快速追踪与补偿,保证了在不同扰动下交直流混合微电网的稳定性。进一步提出了基于NLESO的改进积分滑模控制方法,提高了直流母线电压的控制精度。结合非线性光滑函数设计了滑模趋近律,消除了传统滑模控制中的高频抖振现象。通过Lyapunov理论对系统的稳定性进行分析验证,仿真结果表明该控制方法响应速度快、控制精度高、抗扰动能力强并且无抖振现象。
基金Project supported by Funds for Innovative Research Groups of China （51021005）, National Basic Research Program of China （973 Program） （2009CB724504）, National Natural Science Foundation of China（50707036）.
文摘This paper presents performance analysis on hybrid AC/DC microgrid networks for residential home cluster. The design of the proposed microgrid includes comprehensive types of Distributed Generators (DGs) as hybrid power sources (wind, Photovoltaic (PV) solar cell, battery, fuel cell). Details about each DG dynamic modeling are presented and discussed. The customers in home cluster can be connected in both of the operating modes: islanded to the microgrid or connected to utility grid. Each DG has appended control system with its modeling that will be discussed to control DG performance. The wind turbine will be controlled by AC control system within three sub-control systems: 1) speed regulator and pitch control, 2) rotor side converter control, and 3) grid side converter control. The AC control structure is based on PLL, current regulator and voltage booster converter with using of photovoltaic Voltage Source Converter (VSC) and inverters to connect to the grid. The DC control system is mainly based on Maximum Power Point Tracking (MPPT) controller and boost converter connected to the PV array block and in order to control the system. The case study is used to analyze the performance of the proposed microgrid. The buses voltages, active power and reactive power responses are presented in both of grid-connected and islanded modes. In addition, the power factor, Total Harmonic Distortion (THD) and modulation index are calculated.
文摘为提高风电场交直流混合输电并网的系统性能,提出一种更加灵活的电压源换流器高压直流(voltage source converter based high voltage direct current,VSC-HVDC)控制策略。对于风电场侧电压源换流器,设计了一种新的交流电压–功角控制方法。对于交直流混合输电模式,该方法通过调节风电场交流母线电压与电压源换流器输出电压间的功角来实现定有功功率控制。对于纯柔性直流输电模式,风电场交流母线电压自动被调节为具有恒幅恒频的交流电压,实现了对波动风电的同步输送。该方法中输电模式的变化无需切换控制;另外,通过附加电流高通滤波器增强了对系统谐振的阻尼作用。对电网侧电压源换流器,采用一种新的直接电流矢量控制,使直流电压稳定在参考值上。运用PSCAD/EMTDC仿真软件对分别接入笼型感应发电机(squirrel cage induction generator,SCIG)风电场和双馈感应发电机(doubly fed induction generator,DFIG)风电场的交直流混合输电系统建模仿真。一系列运行条件下的仿真结果验证了控制方法的有效性与可行性。
