A modular high-voltage DC conversion device and its control method

Abstract

The invention provides a modular high-voltage DC conversion device, which is composed of n DC conversion units, n is a positive integer, n≥2, the input ends of the n DC conversion units are connected in series, and the output ends are connected in parallel; the n Among the DC conversion units, k units are redundant units, wherein 0≤k<n; the DC conversion unit consists of an input bypass switch K1, a first fuse F1, a first resistor R1, and a first capacitor C1, The isolated DC / DC converter is composed of an output fuse F2 and a second capacitor C2. The present invention also provides a corresponding control method. When any DC conversion unit fails internally, the isolated DC / DC converter that controls the unit is locked out of operation, and the remaining normal DC conversion units are connected in series to maintain the normal operation of the system. . The invention provides a sub-unit redundant design scheme, which improves the operation reliability of the high-voltage direct-current conversion device.

Description

technical field [0001] The invention belongs to the technical field of direct current transmission and distribution of electric power, and relates to a high-reliability modular high-voltage direct current power conversion device and a control method thereof. Background technique [0002] In order to promote the development of DC power distribution applications, it is necessary to study DC transformation equipment with functions similar to AC isolation transformers to convert high-voltage DC into isolated low-voltage DC that meets the requirements of power distribution equipment. The modular DC / DC conversion topology based on input series and output parallel connection has received extensive attention and research in the industry. [0003] This solution has the advantages of small voltage and current stress of semiconductor devices, low cost, etc., and the capacity of the modular structure is highly scalable. For applications with different voltages and capacities, it is only...

AI Technical Summary

Problems solved by technology

However, there is still a problem with this architecture: the sub-module cannot implement fault redundancy design

However, this patent does not have redundant functions and low reliability

[0005] Chinese patent CN201510097371.0 A high-frequency link bidirectional DC transformer with switched capacitor access and its control method involves a method of implementing redundant design by adding a first-stage half-bridge converter to the front stage of the DC conversion unit, but the method increases The half-bridge brings increased device cost while reducing overall efficiency

[0006] It can be seen that the disadvantage of the current high-voltage DC conversion device scheme is that when a certain DC conversion unit fails, if the DC capacitor at its high-voltage input end is bypassed, it will directly cause the DC capacitor to be short-circuited and discharged, and the discharge current is infinite and there is nowhere to discharge the energy. , resulting in damage to components such as capacitors and system shutdown, it is difficult to achieve fault redundancy and high reliability operation of the main circuit

or, the technical means used to achieve redundancy result in increased device cost while reducing overall efficiency

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