摘要:
A commutation apparatus based on a controllable commutation inductor (3), and an implementation method therefor. The commutation apparatus uses a three-phase half-bridge structure. The three-phase half-bridge structure consists of serially connected commutation units. Each of the commutation units comprises a converter transformer and a converter inverter (2). A commutation inductor is serially connected between the valve side of the converter transformer and the converter inverter. A controllable inductor in the commutation inductor is used together with a control protection system in a converter station. When the converter station normally operates, a switch is turned off, and the controllable inductor is comprised in the commutation inductor; when the control protection system in the converter station detects a commutation failure, the switch is turned on, so that a leakage inductance value of the commutation inductor is lowered, the commutation angle is reduced, and the turn-off angle is increased. The commutation apparatus improves a commutation feature of a converter valve on an inverter side when a commutation failure occurs, and the commutation apparatus has the advantages of requiring less elements, is easy to implement, and requiring low cost.
摘要:
The present invention provides a direct current circuit breaker and its implementation method, which includes the cutout circuit, the commutation circuit and the energy absorption circuit connected in parallel, wherein the cutout circuit includes cutout inductance and cutout unit connected in series, the commutation circuit includes commutation inductance, commutation unit and mechanical switch connected in series, commutation unit has a smaller on-resistance compared to cutout unit. The direct current circuit breaker topology of the present invention is novelty, concise, fully functional, easy to control and can flexible extend to apply to different voltage occasion. Through using power semiconductor switch module to cut off the current, It will have a quickly action, without generating electric arc, while the modular construction also reduces the consistency requirements of the power electronic component, and easy to realize the voltage-sharing of the power semiconductor in series, the capacitor included in the module also plays a role of limiting the current. Commutation circuit and cutout circuit through the full-bridge structure can realize the shunt, reduce the current stress of the power electronic component, and also reduce the component cost.
摘要:
The present invention relates to a valve basic control device and method of a module multilevel converter. The module multilevel converter is provided with a bridge arm including a plurality of cascaded sub-modules, and the converter valve basic control device in a hierarchical control architecture, that includes: a current control unit, used for controlling a current of the converter, generating an input number of the sub-modules of the bridge arm in real time, obtaining a current direction of the bridge arm and sending number information and current direction information; a bridge arm summary control unit, used for determining sub-modules to be input or removed according to the received state of each sub-module and the number information and the current direction information received from the current control unit, and sending a determination result; and a bridge arm segmented control unit, used for inputting or removing the sub-modules according to the determination result received from the bridge arm summary control unit, obtaining the state of each sub-module and sending the state to the bridge arm summary control unit.
摘要:
A novel combined direct current circuit breaker is provided, which includes a transfer branch, an energy absorption branch, at least two primary branches and at least two secondary branches; the transfer branch is connected in parallel with the energy absorption branch; the primary branches are in one-to-one correspondence with the second branches; the primary branches are connected with direct current outgoing lines of a direct current busbar in a high-voltage direct current power transmission system; the secondary branches are connected in series with the transfer branches and then connected in parallel with two ends of the primary branches corresponding to the secondary branches. Compared with the conventional art, the novel combined direct current circuit breaker and an application method thereof improve application economy of the high-voltage direct current circuit breaker in a flexible direct current power grid, and are favorable for construction of the direct current power grid and popularization and application of a hybrid direct current circuit breaker.
摘要:
A Direct Current (DC)-DC conversion system and a control method thereof are provided. The system includes a phase element and a controller. The phase element includes multiple bridge arms. The multiple bridge arms are in star connection and form a common terminal and multiple output terminals. Each of the bridge arms includes a variable voltage source. The controller is connected to each of the variable voltage sources, and is configured to control a voltage of each of the variable voltage sources. Compared with the conventional art, the DC-DC conversion system and control method thereof provided by the invention have the advantages that each of the bridge arms in the phase element forms star connection, so that a circulation current for energy balance only circulates in the system, rather than flowing into a DC system. In addition, the system adopts relatively smaller numbers of power electronic devices and filters, so that the system may be applied to the field of high-voltage high-capacity DC power transmission and may reduce limits of inductive devices to DC power transmission of the DC-DC conversion system.