WO2023035439A1

WO2023035439A1 - Processing apparatus for output excitation of grid-connected converter

Info

Publication number: WO2023035439A1
Application number: PCT/CN2021/136189
Authority: WO
Inventors: 李小锋; 王文才; 吴凯; 王正云; 刘湘
Original assignee: 株洲福德轨道交通研究院有限公司; 广东福德电子有限公司; 湖南福德电气有限公司
Priority date: 2021-09-09
Filing date: 2021-12-07
Publication date: 2023-03-16
Also published as: CN216851804U

Abstract

The present utility model relates to a processing apparatus for output excitation of a grid-connected converter. The processing apparatus comprises an input port, an output port, a current-limiting resistor R, a timing apparatus T, a normally-on electric control switch K, and a filter capacitor C. The input port is connected to the output port separately via the current-limiting resistor R, the normally-on electric control switch K, and the filter capacitor C, and the current-limiting resistor R, the normally-on electric control switch K, and the filter capacitor C are connected in parallel. The timing apparatus T is used for performing timing control on the normally-on electric control switch K so as to turn on and off. The processing apparatus of the present utility model solves the problem of overcurrent caused by magnetic saturation of an output excitation transformer or a large generator due to excessive instantaneous output current. Moreover, the processing apparatus has a simple structure, and is low-cost and easy to use.

Description

A processing device for output excitation of grid-connected converter

technical field

The invention relates to the field of power control and excitation applications, and is mainly used in applications with large excitation transformers or large generators.

Background technique

The grid-connected converter can feed back electric energy to the grid, so it can be used in applications such as energy storage or power stations, and its output end generally has a large transformer or generator. A transformer or generator can be equivalently regarded as a large inductance, which will generate a large induced electromotive force at the moment of output current, and then generate a large excitation current, resulting in magnetic saturation of the transformer or generator. Among them, the excitation current can not only cause huge damage to the performance of the transformer or generator, but also have a huge impact on the controllable or uncontrollable converter devices in the front-end grid-connected converter, and even cause damage to the converter devices. At the same time, If the excitation current is fed back to the grid, huge harmonics will also be generated, so it is very important to solve the excitation current problem.

technical problem

At present, the commonly used method adopts the software soft start method, and its control method is very complicated and difficult to implement. The invention adopts an external modular device, which has a simple implementation method, low cost, and is easy to use.

technical solution

In order to improve the deficiencies of the prior art, the invention provides a processing device for output excitation of a grid-connected converter.

According to one aspect of the present invention, a processing device for output excitation of a grid-connected converter is provided. The processing device includes an input port, an output port, a current limiting resistor R, a timing device T, a normally open electric control switch K, a filter Capacitor C, the input port is respectively connected to the output port through the current limiting resistor R, the normally open electronic control switch K, and the filter capacitor C, and the current limiting resistor R, the normally open electronic control switch K, and the filter capacitor C are three The ones are connected in parallel; the timing device T is used to control the opening and closing of the normally open electric control switch K at regular intervals.

Wherein, the processing device is connected in series on the line between the grid-connected converter and the excitation transformer device, and the excitation transformer device is a transformer or a generator.

Wherein, copper bars are used in the processing device to connect the current transmission lines.

Wherein, the normally open electric control switch K is a normally open contactor or a semi-controlled device.

Wherein, the half-controlled device is an IGBT tube.

Wherein, the timing device T is a time relay.

Wherein, the processing device includes an external interface for externally controlling the on-off of the normally-open electric control switch K.

Beneficial effect

The processing device created by the invention solves the problem of overcurrent caused by magnetic saturation of the output excitation transformer or large generator due to excessive instantaneous output current, has better practical application value, and is simple in structure, low in cost and easy to use .

The description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the stated and other purposes, features and advantages of the present invention To make it more obvious and easy to understand, the specific implementation manners of the invention are enumerated below.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating preferred embodiments and are not to be considered as limiting the invention. Also throughout the drawings, the same stage is denoted by the same reference numeral.

In the attached picture:

Fig. 1 shows the topological diagram of the processing device created by the present invention;

Figure 2 shows the main topology of a grid-connected converter with three-phase input and single-phase output;

Fig. 3 shows the connection mode between the processing device of the present invention and the converter and excitation transformer.

Embodiments of the present invention

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

As shown in Figure 1, the processing device created by the present invention is composed of an input port, an output port, a current limiting resistor R, a timing device T, a normally open electronic control switch K, and a filter capacitor C. The normally open electric control switch K and the filter capacitor C are connected to the output port, in which the current limiting resistor R, the normally open electric control switch K, and the filter capacitor C are connected in parallel, and the timing device T is used for timing control of the normally open electric control switch K performs opening and closing.

In one embodiment, the normally open electric control switch K is a normally open contactor, which uses a coil to energize to generate a magnetic field to close the contacts, and has its own overload protection function, which can improve the overcurrent protection capability of the processing device.

In another embodiment, the normally open electronic control switch K is a semi-controlled device such as MOS, IGBT, etc., to realize frequent on-off circuits, wherein the semi-controlled device is preferably an IGBT tube, and its rated current is 4500V/3000A , can work reliably in a high current and high power environment, and comes with an anti-series diode to prevent surges.

On the basis that the normally open electric control switch K is a normally open contactor or a semi-controlled device, the timing device T is selected as a time relay, which can produce a jumping change in the level and continue to output the level after the jump, which is very suitable for The control of normally open contactor or semi-controlled device simplifies the circuit structure.

In the present invention, the connection of the current transmission line in the input port, the output port, the current limiting resistor R, the timing device T, the normally open electric control switch K, and the filter capacitor C is realized by copper bars, so that the lines can be Transmission of high currents allows the processing unit to work in applications with large excitation transformers or large generators.

Further, the processing device adopts a modular package, which is easy to integrate and use.

In the present invention, as shown in Figure 2 and Figure 3, the processing device is connected in series on the line between the grid-connected converter and the excitation transformer device, wherein the excitation transformer device is a transformer or a generator, when the grid-connected When the converter turns on the output, the contactor of the processing device is in an open circuit state, and the output is provided to the excitation transformer device through the device. Due to the existence of the current limiting resistor R and the filter capacitor C, the current output will be limited, and the excitation transformer will not be caused. The voltage device generates excessive induced electromotive force and magnetic saturation occurs. After a certain period of time, the excitation transformer device establishes the excitation, and the time relay automatically turns off when the time comes. The current is directly output to the excitation transformer device through the contactor to ensure normal output.

Further, the processing device also provides an external interface for externally controlling the on-off of the contactor, and the on-off of the contactor can be forcibly controlled through the interface.

In the description provided herein, numerous specific details are set forth. However, it is understood that inventive embodiments may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

Claims

A processing device for output excitation of a grid-connected converter, characterized in that:

The processing device includes an input port, an output port, a current limiting resistor R, a timing device T, a normally open electric control switch K, and a filter capacitor C. The filter capacitor C is connected to the output port, and the current limiting resistor R, the normally open electric control switch K, and the filter capacitor C are connected in parallel;

The timing device T is used for timing control of the normally open electric control switch K to open and close.
The processing device according to claim 1, wherein the processing device is connected in series on the line between the grid-connected converter and the excitation transformer device, and the excitation transformer device is a transformer or a generator.
The processing device according to claim 1, characterized in that: copper bars are used in the processing device to connect the current transmission lines.
The processing device according to claim 1, characterized in that: the normally open electric control switch K is a normally open contactor or a semi-controlled device.
The processing device according to claim 1, wherein the semi-controlled device is an IGBT tube.
The processing device according to claim 2, characterized in that: the timing device T is a time relay.
The processing device according to claim 1, characterized in that: the processing device includes an external interface for externally controlling the on-off of the normally-open electric control switch K.