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公开(公告)号：US10396562B2
公开(公告)日：2019-08-27
申请号：US16319300
申请日：2017-08-15
发明人： Ruhai Huang , Yu Lu , Yunlong Dong , Lei Pan , Defeng Qiu , Chongxue Jiang , Jiang Lu , Gang Li , Zhaoqing Hu , Nannan Wang , Jiudong Ding , Ke Wang , Xianlai Hu , Hui Wang , Shunke Sui
摘要： A series compensation device suitable to double-circuit lines is disclosed. The device includes one series transformer and one converter. One converter and dual-circuit transmission lines are respectively connected to three windings of one series transformer. In the solution provided in the present application, the device can be independently installed in a power transmission system to be used as a static synchronous series compensator, and can also be used as a component of a unified power flow controller, a convertible static compensator, an interline power flow controller and a unified power quality conditioner to be connected to a power transmission system device in series. The device can save the capacity of a converter, improve the application efficiency of the series compensation device, and reduce the cost and area occupation.
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公开(公告)号：US11374411B2
公开(公告)日：2022-06-28
申请号：US16759309
申请日：2018-10-23
发明人： Jiacheng Wang , Yu Lu , Nannan Wang , Zhaoqing Hu , Yunlong Dong , Gang Li , Chongxue Jiang
摘要： The invention relates to an island converter overload limit method and device for a bipolar flexible DC transmission system, and belongs to the field of DC transmission. During stable island operation, both bipolar converters adopt a voltage-frequency droop control strategy; and once it is detected that one converter is overloaded, the control mode of the overloaded converter is automatically switched to active-wattless power control from voltage-frequency droop control to fulfill an overload limit function. The method effectively avoids an overload of the bipolar flexible DC transmission system under island operation, effectively maintains the AC voltage and frequency stable, and has important guiding significance for applying island systems to DC power grids.
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公开(公告)号：US10461525B2
公开(公告)日：2019-10-29
申请号：US16336064
申请日：2017-08-18
发明人： Zhaoqing Hu , Yunlong Dong , Ke Wang , Haiying Li , Dongming Cao
摘要： A fault current limiting control and protection coordination method for a converter of a flexible direct current transmission system operating in an islanding state is provided. The current output command limit Imax is used to limit the current commands of inner loop currents, and in the event of a fault, Imax is set equal to or slightly larger than a value for an AC line overcurrent protection section.
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公开(公告)号：US11329486B2
公开(公告)日：2022-05-10
申请号：US16607847
申请日：2018-04-27
发明人： Ke Wang , Shunke Sui , Yu Lu , Yunlong Dong , Zhaoqing Hu , Gang Li
摘要： During initiation under an isolated island condition, the amplitude of a voltage reference wave output generated by a flexible DC transmission control and protection system is in a segmented mode, wherein a first segment of the reference wave amplitude begins at zero or a fixed value Ux and rapidly increases to Ua kV at a rate of a kV/s, avoiding a low output voltage reference wave and high error and harmonic content of a sampled voltage and current. A second segment increases to Ub kV at a rate of β kV/s, a third segment increases to Uc kV at a rate of γ kV/s, and the Nth segment increases to a rated voltage of UN kV at a rate of ε kV/s, thereby achieving non-disturbance and shockless initiation of a flexible DC transmission system under an isolated island condition.
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公开(公告)号：US11146071B2
公开(公告)日：2021-10-12
申请号：US16770458
申请日：2018-11-28
发明人： Jiang Lu , Yu Lu , Yunlong Dong , Yongping Wang , Jie Tian , Haiying Li , Zhaoqing Hu , Nannan Wang , Ke Wang , Jiudong Ding
摘要： A coordinated control method for series voltage source converter valve groups comprises: allocating a total direct-current voltage reference value or a total active power reference value at the end where a direct-current electrode series voltage source converter valve group is located according to the total number of voltage source converter valve groups in series; for a direct-current voltage control end, controlling the direct-current voltage of each valve group according to the assigned direct-current voltage reference value for each valve group; for an active power control end, controlling the active power of each valve group according to the assigned active power reference value for each valve group and based on adding the active power compensation amount of the valve group which has voltage equalization effects on the valve group. Correspondingly, also providing a coordinated control device for series voltage source converter valve groups. The direct-current voltage equalization of each valve group in operation of the direct-current voltage control end or the active power control end of the series voltage source converter valve group is achieved.
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公开(公告)号：US20210222673A1
公开(公告)日：2021-07-22
申请号：US16759309
申请日：2018-10-23
发明人： Jiacheng Wang , Yu Lu , Nannan Wang , Zhaoqing Hu , Yunlong Dong , Gang Li , Chongxue Jiang
摘要： The invention relates to an island converter overload limit method and device for a bipolar flexible DC transmission system, and belongs to the field of DC transmission. During stable island operation, both bipolar converters adopt a voltage-frequency droop control strategy; and once it is detected that one converter is overloaded, the control mode of the overloaded converter is automatically switched to active-wattless power control from voltage-frequency droop control to fulfill an overload limit function. The method effectively avoids an overload of the bipolar flexible DC transmission system under island operation, effectively maintains the AC voltage and frequency stable, and has important guiding significance for applying island systems to DC power grids.
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公开(公告)号：US10270332B2
公开(公告)日：2019-04-23
申请号：US16081437
申请日：2017-04-06
发明人： Zhaoqing Hu , Yunlong Dong , Yu Lu , Haiying Li , Dongming Cao
IPC分类号： H02M1/32 , G05F1/70 , G05F1/66 , H02J3/36 , H02M5/458 , H02H5/04 , H02H9/00 , H02H7/12 , H02J3/18 , G01R21/00 , H02M1/00 , H02M7/483
摘要： According to the overload current limiting method for a voltage source converter, when a pole control system receives a water-cooling overload current limiting instruction, an active and reactive instruction are changed at the same time according to a specified slope, so that an absolute value of an arm current of the converter decreases in a fixed slope, and can be ensured that active power and reactive power fall to zero at the same time, and a water-cooling load limiting aim of the converter can be achieved by reducing the arm current. After a water-cooling overload power limiting instruction received by the pole control system is cancelled, a current value of the active power and the inactive power remain unchanged. When a water-cooling overload power limiting instruction is received again, decrease continues on the basis of current power values until the power falls to zero.
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公开(公告)号：US10523131B2
公开(公告)日：2019-12-31
申请号：US16322457
申请日：2017-08-02
发明人： Gang Li , Jianchun Li , Jie Tian , Haiying Li , Yu Lu , Yunlong Dong , Zhaoqing Hu , Minglian Zhu
摘要： A reconfigurable MMC sub-module unit and a control unit thereof are provided, the reconfigurable MMC sub-module unit is mainly formed by an MMC sub-module unit and a reconfigurable mechanism, wherein the reconfigurable mechanism is formed by switches, and the conversion of MMC sub-module unit topology is achieved through switching on and off the switches in the reconfigurable mechanism. According to the reconfigurable MMC sub-module unit and the control unit thereof, the rapid change of a topology structure for a converter can be achieved, which is suitable for the demand of the line connection of the medium-voltage power distribution network and variable topologies, and meets requirements of dynamic simulation experiment for different converter topologies in the dynamic simulation experiment, thereby reducing construction costs and duration, improving experiment efficiency, and having high flexibility and strong versatility.
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公开(公告)号：US10326275B2
公开(公告)日：2019-06-18
申请号：US16086317
申请日：2017-04-19
发明人： Ke Wang , Gang Li , Yu Lu , Yunlong Dong , Jiang Lu , Zhaoqing Hu , Tiangui Jiang
摘要： Provided is a method for controlling a zero sequence voltage of a voltage source converter. When an alternating current system ground fault occurs, a zero sequence voltage at an alternating current (AC) side or a zero sequence voltage at a direct current (DC) side of a converter is detected. If the detected zero sequence voltage is greater than a set value V0ref, a DC side voltage of the converter can be increased to a set value Udc0, thereby generating an appropriate reference wave at the AC side of the converter to match an AC voltage, and accordingly controlling overmodulation of a reference wave at a faulty station to suppress fluctuation of a DC voltage.
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公开(公告)号：US20180219380A1
公开(公告)日：2018-08-02
申请号：US15534024
申请日：2015-12-09
发明人： Yunlong Dong , Jie Tian , Zhaoqing Hu , Haiying Li , Dongming Cao , Haibin Liu , Yu Lu
CPC分类号： H02J3/36 , H02H7/1222 , H02J3/38 , H02J2003/388 , H03L7/08 , Y02E60/60
摘要： The present invention discloses a passive islanding to grid-connection switching method for a VSC HVDC transmission system. When the VSC HVDC transmission system in an island operation state, whether the VSC HVDC transmission system enters an grid-connection state is determined by detecting whether an overcurrent phenomenon has occurred in a converter valve-side three-phase alternating-current or a converter bridge arm current, and detecting a change status of an alternating-current side voltage. The system is controlled to switch from an island operation control mode to a grid-connection control mode. At a moment of switching, the online control mode is smoothly switched to by changing a power instruction and performing phase tracking on a current grid voltage, so that continuous operation of the system is maintained.
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