An energy dissipation device and a control method

Abstract

An energy dissipation device comprises at least two voltage-equalizing energy dissipation modules and at least two first power semiconductor devices, wherein the at least two voltage-equalizing energydissipation modules are connected in series in the same direction to form an energy dissipation unit, and the at least two first power semiconductor devices are connected in series in the same direction to form a single conduction unit, and the single conduction unit is connected in series with the energy dissipation unit; A DC capacitor branch, an energy dissipation branch and a bypass branch are connected in parallel to form the voltage-equalizing energy dissipation module; and that energy dissipation branch is composed of a second power semiconductor device and an energy dissipation resistor connected in series; The invention also discloses a control method based on an energy dissipation device. When the voltage of a DC line is increased, the switch-on / off of the energy dissipation resistance can be controlled by controlling a second power semiconductor device to stabilize the DC voltage. When the voltage equalization energy dissipation module is faulty, a fuse and a bypass switchare adopted to ensure the reliability of the device. The energy dissipation device has the advantages of high cost performance, high reliability and easy realization.

Description

technical field [0001] The invention belongs to the technical field of high-power electric current conversion, and in particular relates to an energy consumption device and a control method. Background technique [0002] In HVDC power transmission system, energy consumption device is a crucial equipment. The energy consumption device is mainly used in the application scenario of island power supply. If the power generation end is an inertial power source similar to wind power, when the power receiving end fails, because the power cannot be sent out, energy will be accumulated on the DC side, causing the voltage of the DC transmission line to rise. High, causing harm to the safe operation of the equipment. [0003] The commonly used technical solution in the prior art is to use power semiconductor devices, such as IGBT directly connected in series and a centralized resistance solution. The IGBT valve string is subjected to high voltage, and the concentrated resistance consum...

AI Technical Summary

Problems solved by technology

The energy consumption device is mainly used in the application scenario of island power supply. If the power generation end is an inertial power source similar to wind power, when the power receiving end fails, because the power cannot be sent out, energy will be accumulated on the DC side, causing the voltage of the DC transmission line to rise. High, causing harm to the safe operation of the equipment

[0003] The commonly used technical solution in the prior art is to use power semiconductor devices, such as IGBT directly connected in series and a centralized resistance solution. The IGBT valve string is subjected to high voltage, and the concentrated resistance consumes energy. The consistency requirements for opening and closing are extremely high. Once there is inconsistency, some valve sections will be over-pressured and burned. Due to the continuous opening and closing during work, the risk of device damage is high; there are also technical solutions that propose modular solutions, but The solution has the defects of large number of components, high cost, and low reliability, such as the solution proposed in the patent CN102132484B-converter with distributed braking resistors, such as image 3 As shown, the main defect of this scheme is that the potential of the bridge arm composed of diodes in the figure is complex: the upper tube of the diode bridge arm is connected to the adjacent module, and the capacitor cannot clamp it, and when the device is running, Due to the complex operation mode, when the work between modules is not synchronized, the potential between the modules is uncertain, and the diode has the risk of overvoltage breakdown; at the same time, the number of devices in this scheme is large, including 4 groups of power semiconductor devices. The reliability of power semiconductor devices is relatively low, which makes the failure rate of the whole module higher and the cost is higher; this scheme includes two bridge arms composed of power semiconductor devices in one module, and there is a potential connection between the bridge arms. Increased the difficulty of structural design; in order to overcome the above defects, the present invention provides a solution with low cost and high reliability

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