A Virtual Capacitor Control Method Applied to Converter Stations of DC Distribution Network
A technology of DC distribution network and virtual capacitor, applied in the direction of DC network circuit device, power transmission AC network, electrical components, etc., can solve the problem of frequent load fluctuations in DC distribution network, late development of DC distribution network, and immature control technology. and other problems, to achieve the effect of stabilizing power distribution performance, improving dynamic regulation performance, and ensuring DC voltage
Active Publication Date: 2022-05-24
SOUTHEAST UNIV +2
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Problems solved by technology
Although the DC distribution network provides a broader prospect for new technologies and smart grids, due to the relatively late development of the DC distribution network, its control technology is not yet mature enough, and most of the control technologies now refer to multi-terminal flexible DC transmission and low-voltage Some control methods in the DC microgrid, among which the voltage coordination control methods suitable for the DC distribution network mainly include three types: master-slave control, voltage margin control and droop control, but because the load fluctuation of the DC distribution network is more frequent, it contains A large number of distributed energy sources, the power flow is more flexible, these three types of traditional control methods cannot have good steady-state performance and dynamic performance at the same time
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[0037] by image 3 The structure of the double-ended annular DC distribution network is shown as an example, the tie switches S1 and S2 are closed, the system is in double-ended annular operation mode, i=2, VSC1 is set as the main station to work in constant voltage control mode, and VSC2 is set In order to use the controller designed by the present invention from the converter station, the design of the virtual capacitor controller specifically includes the following steps:
[0038] The first step is to calculate the equivalent value C of the DC side capacitance of the converter station according to the number of sub-modules of the bridge arm of the converter station and the capacitance value of the sub-modules dc , in order to offset the DC side voltage fluctuation caused by the power unbalance of the equivalent capacitor, a virtual capacitor C is designed vir in parallel with the equivalent capacitance, and let the virtual capacitance value C vir =C dc .
[0039] The se...
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The invention discloses a virtual capacitor control method applied to a converter station of a direct current distribution network. Including: based on the principle of power and energy balance when charging and discharging capacitors, a product-difference voltage regulation equation based on instantaneous power is designed to calculate in real time the active power required to maintain the DC voltage stability of the DC side of the converter station; the proposed control The method is applied to the slave converter station of the DC distribution network using master-slave control. When the system is in a steady state, it can ensure the power distribution accuracy of the system during steady-state operation; when the DC distribution network suffers from large disturbances and operating mode switching occurs , the virtual capacitor can quickly provide inertial support for the DC distribution network, improve the dynamic adjustment performance of the DC voltage, and ensure the stability of the DC voltage of the DC distribution system.
Description
technical field [0001] The invention belongs to the technical field of direct current distribution network control, and relates to a virtual capacitor control method of a converter station in a direct current distribution network. Background technique [0002] Compared with the AC distribution network, the DC distribution system can realize closed-loop operation, has a variety of power supply methods, and the power flow is flexible and controllable, which is more conducive to the integration and consumption of renewable energy such as wind power generation and solar power generation. Although the DC distribution network provides broader prospects for new technologies and smart grids, due to the relatively late development of the DC distribution network, its control technology is not mature enough. Some control methods in the DC microgrid, among which the voltage coordination control methods applicable to the DC distribution network mainly include three categories: master-sla...
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IPC IPC(8): H02J1/00H02J3/36
CPCH02J1/00H02J3/36Y02E60/60
Inventor 吴在军谢兴峰司鑫尧杨景刚肖小龙杨媛平曹骁勇刘洋刘瑞煌
Owner SOUTHEAST UNIV