DC energy consumption device and control method

Abstract

The invention discloses a DC energy consumption device, which comprises at least two voltage-sharing energy consumption modules and at least two first power semiconductor devices, wherein the at leasttwo voltage-sharing energy consumption modules are connected in series in the same direction to form an energy consumption unit, the at least two first power semiconductor devices are connected in series in the same direction to form a one-way conduction unit, and the one-way conduction unit is connected with the energy consumption unit in series. Each voltage-sharing and energy-consuming moduleis formed by connecting a DC capacitor and an energy-consuming branch in parallel; the energy-consuming branch is formed by connecting a second power semiconductor device and an energy-consuming resistor in series. The invention further discloses a control method based on the DC energy consumption device. When the voltage of a DC line rises, the second power semiconductor device can be controlledto control the on-off of the energy consumption resistor so as to stabilize the DC voltage. When the voltage-sharing energy consumption module breaks down, multiple bypass modes are adopted, so that the reliability of the device is guaranteed. The device is very high in cost performance, high in reliability and easy to implement.

Description

technical field [0001] The invention belongs to the technical field of high-power electric current conversion, and in particular relates to a direct current energy consumption device and a control method. Background technique [0002] In HVDC power transmission system, DC energy consumption device is a crucial equipment. The DC 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, the energy will be accumulated on the DC side, resulting in the voltage of the DC transmission line. If it rises, it will endanger 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 c...

AI Technical Summary

Problems solved by technology

The DC 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, the energy will be accumulated on the DC side, resulting in the voltage of the DC transmission line. Elevated, 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 Figure 4 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

Images