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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：US11355932B2
公开(公告)日：2022-06-07
申请号：US16644225
申请日：2018-05-22
发明人： Nannan Wang , Yu Lu , Yunlong Dong , Jie Tian , Chongxue Jiang , Jiacheng Wang , Gang Li , Jiudong Ding , Haiying Li
摘要： Disclosed are a control method and system for a parallel converter system, including a common AC voltage controller and a separate current controller for each converter; the AC voltage controller generates an active current, a wattless current, and a system voltage phase reference value and, by means of communication, sends same to the current controller of each converter in island control mode to be a converter control signal; the active and wattless current outputted by each converter, along with the corresponding current reference value, accomplish the objective of the parallel converter system collectively controlling the amplitude and frequency of an AC bus voltage. The method and system are highly reliable and effectively ensure the synchronization of a plurality of converters.
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公开(公告)号：US11190020B2
公开(公告)日：2021-11-30
申请号：US16643472
申请日：2018-05-07
发明人： Nannan Wang , Yu Lu , Yunlong Dong , Jie Tian , Dongming Cao , Haiying Li , Chongxue Jiang , Jiacheng Wang
摘要： A DC voltage coordination control method is applied to a multi-terminal VSC-HVDC power transmission system or a VSC-HVDC power grid system. When a lower-level control is used in the active power control mode, the active power reference value of the converter is generated according to the converter DC voltage and the converter DC voltage active power curve; it also includes an upper-level control to adjust the control mode and active power setting value of the lower-level control to ensure the steady-state performance of the system. This method has low dependence on communication, avoids the problem that the fixed slope and margin cannot meet all operating conditions, and is suitable for large-scale VSC-HVDC systems, and has scalability.
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公开(公告)号：US10164428B2
公开(公告)日：2018-12-25
申请号：US15308842
申请日：2015-02-05
发明人： Guorong Shen , Jie Tian , Dongming Cao , Haiying Li , Yunlong Dong , Nannan Wang , Haibin Liu , Yu Lu
摘要： The disclosure is related to a voltage-source multi-level converter including a phase unit. The phase unit includes first and second bridge arms, each includes modules and reactor connected in series. In the first bridge arm, a first terminal of first reactor is connected to alternating-current terminal of the phrase unit, a second terminal thereof is connected to a first terminal of the first modules, and second terminal of the first modules is connected to first DC terminal of the phrase unit. In the second bridge arm, a first terminal of the second reactor is connected to the alternating-current terminal, a second terminal thereof is connected to a first terminal of the second modules, and a second terminal of the second modules is connected to second DC terminal of the phrase unit. Then, a parallel fault shunt circuit is connected between the second terminals of the first and second reactors.
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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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8.发明授权公开(公告)号：US10797487B2
公开(公告)日：2020-10-06
申请号：US16345426
申请日：2017-11-24
发明人： Jiang Lu , Yu Lu , Yunlong Dong , Nannan Wang , Yongping Wang , Wenqiang Zhao , Jie Tian , Haiying Li
摘要： Provided is an on-line input and quit control method for a voltage-source converter unit. The method achieves the on-line input of a voltage-source converter unit by means of performing steps, such as charging control, deblocking transfer control and operation adjustment control, on a voltage-source converter to be input, and achieves the on-line quitting of the voltage-source converter unit by means of performing steps, such as direct-current voltage reduction control, bypass transfer control and converter blocking control, on a voltage-source converter to be quit. Correspondingly, provided is an on-line input and quit control device for a voltage-source converter unit, which can achieve the on-line steady input and quitting of a voltage-source converter in a series-type hybrid direct-current power transmission system or a series-type flexible direct-current power transmission system, without affecting the normal and stable operation of other already running converters.
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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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10.发明申请DIRECT-CURRENT POWER TRANSMISSION PROTECTION DEVICE, CONVERTER AND PROTECTION METHOD 审中-公开直流电力传输保护装置，转换器和保护方法公开(公告)号：US20170047727A1
公开(公告)日：2017-02-16
申请号：US15118669
申请日：2014-05-04
发明人： Dongming Cao , Yeyuan Xie , Zhenxia Shao , Yu Lu , Min Li , Haibin Lu , Haiying Li
CPC分类号： H02H3/202 , H02H7/10 , H02H7/1227 , H02H7/1252 , H02H7/1257 , H02H7/127 , H02M1/32 , H02M7/2173 , H02M2007/4835 , H05K7/20927
摘要： The present invention discloses a direct-current power transmission protection device, including a resistor unit and a bidirectional circulation current switch unit, and the resistor unit and the bidirectional circulation current switch unit being connected in parallel to form the protection device, where at least one resistor is cascaded to form the resistor unit, and at least one bidirectional circulation current switch is cascaded to form the bidirectional circulation current switch unit. In addition, the present invention also provides a converter including the protection device, and at least one protection device is connected in series in each phase unit. The present invention provides the protection device, the converter and a protection method for flexible direct-current power transmission, which can rapidly and effectively suppress direct-current short circuit current and damp current oscillation, and not only can better protect equipment safety, but also can greatly shorten fault current attenuation time, thus shortening direct-current shutdown time and further decreasing economic loss and system destabilization risk caused by shutdown to the max. Moreover, the protection device is structurally simple and low in cost, and has good implementability and economic efficiency.
摘要翻译： 本发明公开了一种直流电力传输保护装置，包括电阻单元和双向循环电流开关单元，并且电阻单元和双向循环电流开关单元并联连接以形成保护装置，其中至少一个 电阻器级联形成电阻器单元，并且至少一个双向循环电流开关级联以形成双向循环电流开关单元。 此外，本发明还提供一种包括保护装置的转换器，并且至少一个保护装置在每个相位单元中串联连接。 本发明提供了保护装置，转换器和柔性直流输电的保护方法，可以快速，有效地抑制直流短路电流和潮流振荡，不仅可以更好地保护设备安全，而且还可以 可以大大缩短故障电流衰减时间，从而缩短直流关机时间，进一步降低停机造成的经济损失和系统不稳定风险。 此外，保护装置结构简单，成本低，具有良好的可实施性和经济效益。
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