Three speed controllers for an axial magnetic flux switched reluctance motor with only one stator, are described and experimentally tested. As it is known, when current pulses are imposed in their windings, high rippl...Three speed controllers for an axial magnetic flux switched reluctance motor with only one stator, are described and experimentally tested. As it is known, when current pulses are imposed in their windings, high ripple torque is obtained. In order to reduce this ripple, a control strategy with modified current shapes is proposed. A workbench consisting of a machine prototype and the control system based on a microcontroller was built. These controllers were: a conventional PID, a fuzzy logic PID and a neural PID type. From experimental results, the effective reduction of the torque ripple was confirmed and the performance of the controllers was compared.展开更多
An alternating current(AC)microgrid is a system that integrates renewable power,power converters,controllers and loads.Hierarchical control can manage the frequency of the microgrid to prevent imbalance and collapse o...An alternating current(AC)microgrid is a system that integrates renewable power,power converters,controllers and loads.Hierarchical control can manage the frequency of the microgrid to prevent imbalance and collapse of the system.The existing frequency control methods use traditional proportion integration(PI)controllers,which cannot adjust PI parameters in real-time to respond to the status changes of the system.Hierarchical control driven by fuzzy logic allows real-time adjustment of the PI parameters and the method used a two-layer control structure.The primary control used droop control to adjust power distribution,and fuzzy logic was used in the voltage loop of the primary control.The secondary control was added to make up for frequency deviation caused by droop control,and fuzzy logic was used in the secondary frequency control to deal with the dynamic change of frequency caused by the disturbances of loads.The proposed method was simulated in Matlab/Simulink.In the primary control,the proposed method reduced the total harmonic distortion(THD)of two cycles of the output voltage from 4.19%to 3.89%;in the secondary control,the proposed method reduced the frequency fluctuation of the system by about 0.03 Hz and 0.04 Hz when the load was increased and decreased,respectively.The results show that the proposed methods have a better effect on frequency maintenance and voltage control of the AC microgrid.展开更多
直流变压器是互联网数据中心(Internet Data Center,IDC)配电系统的重要单元,其技术水平影响着整个IDC配电系统的运营水平。以逻辑链路控制(Logical Link Control,LLC)谐振变换器为基础单元模块,以输入串联、输出并联为拓扑结构,设计了...直流变压器是互联网数据中心(Internet Data Center,IDC)配电系统的重要单元,其技术水平影响着整个IDC配电系统的运营水平。以逻辑链路控制(Logical Link Control,LLC)谐振变换器为基础单元模块,以输入串联、输出并联为拓扑结构,设计了一款基于IDC配电系统的直流变压器。首先介绍了直流变压器系统的拓扑结构,并分析了其均压均流特性;其次又提出了一种三环控制策略,主要对直流变压器系统进行均压均流控制,该策略可以使系统稳定输出额定电压,并使系统具有良好的均压均流效果;最后设计一款10 kV/400 V的直流变压器系统,实验表明该系统运行效果良好,具有较高的稳定性和调节能力。展开更多
三相多功能光伏逆变器的独立逆变功能一般采用基于d-q坐标变换的双闭环控制策略。在没有负载电流前馈的条件下,独立光伏逆变器抗负载扰动能力差,超调严重。针对这一问题提出一种非线性控制方法,根据电压的偏差通过逻辑切换改变电感电流...三相多功能光伏逆变器的独立逆变功能一般采用基于d-q坐标变换的双闭环控制策略。在没有负载电流前馈的条件下,独立光伏逆变器抗负载扰动能力差,超调严重。针对这一问题提出一种非线性控制方法,根据电压的偏差通过逻辑切换改变电感电流内环反馈大小,该方法相当于改变了系统的等效阻尼,从而改善系统的动态性能。利用PSIM和MATLAB进行联合仿真并根据仿真分析结果设计100 k W三相光伏独立逆变器,仿真和试验结果验证了所提方法的有效性。展开更多
文摘Three speed controllers for an axial magnetic flux switched reluctance motor with only one stator, are described and experimentally tested. As it is known, when current pulses are imposed in their windings, high ripple torque is obtained. In order to reduce this ripple, a control strategy with modified current shapes is proposed. A workbench consisting of a machine prototype and the control system based on a microcontroller was built. These controllers were: a conventional PID, a fuzzy logic PID and a neural PID type. From experimental results, the effective reduction of the torque ripple was confirmed and the performance of the controllers was compared.
基金National Natural Science Foundation of China(No.62303107)Fundamental Research Funds for the Central Universities,China(Nos.2232022G-09 and 2232021D-38)Shanghai Sailing Program,China(No.21YF1400100)。
文摘An alternating current(AC)microgrid is a system that integrates renewable power,power converters,controllers and loads.Hierarchical control can manage the frequency of the microgrid to prevent imbalance and collapse of the system.The existing frequency control methods use traditional proportion integration(PI)controllers,which cannot adjust PI parameters in real-time to respond to the status changes of the system.Hierarchical control driven by fuzzy logic allows real-time adjustment of the PI parameters and the method used a two-layer control structure.The primary control used droop control to adjust power distribution,and fuzzy logic was used in the voltage loop of the primary control.The secondary control was added to make up for frequency deviation caused by droop control,and fuzzy logic was used in the secondary frequency control to deal with the dynamic change of frequency caused by the disturbances of loads.The proposed method was simulated in Matlab/Simulink.In the primary control,the proposed method reduced the total harmonic distortion(THD)of two cycles of the output voltage from 4.19%to 3.89%;in the secondary control,the proposed method reduced the frequency fluctuation of the system by about 0.03 Hz and 0.04 Hz when the load was increased and decreased,respectively.The results show that the proposed methods have a better effect on frequency maintenance and voltage control of the AC microgrid.
文摘直流变压器是互联网数据中心(Internet Data Center,IDC)配电系统的重要单元,其技术水平影响着整个IDC配电系统的运营水平。以逻辑链路控制(Logical Link Control,LLC)谐振变换器为基础单元模块,以输入串联、输出并联为拓扑结构,设计了一款基于IDC配电系统的直流变压器。首先介绍了直流变压器系统的拓扑结构,并分析了其均压均流特性;其次又提出了一种三环控制策略,主要对直流变压器系统进行均压均流控制,该策略可以使系统稳定输出额定电压,并使系统具有良好的均压均流效果;最后设计一款10 kV/400 V的直流变压器系统,实验表明该系统运行效果良好,具有较高的稳定性和调节能力。
文摘三相多功能光伏逆变器的独立逆变功能一般采用基于d-q坐标变换的双闭环控制策略。在没有负载电流前馈的条件下,独立光伏逆变器抗负载扰动能力差,超调严重。针对这一问题提出一种非线性控制方法,根据电压的偏差通过逻辑切换改变电感电流内环反馈大小,该方法相当于改变了系统的等效阻尼,从而改善系统的动态性能。利用PSIM和MATLAB进行联合仿真并根据仿真分析结果设计100 k W三相光伏独立逆变器,仿真和试验结果验证了所提方法的有效性。
