CN215990211U

CN215990211U - Chopper resistor branch circuit for energy consumption

Info

Publication number: CN215990211U
Application number: CN202122347462.9U
Authority: CN
Inventors: 翁海清; 张海涛; 易荣; 鲁挺
Original assignee: BEIJING RONGXIN HUIKE TECHNOLOGY CO LTD; Rongxin Huike Electric Co ltd
Current assignee: BEIJING RONGXIN HUIKE TECHNOLOGY CO LTD; Rongxin Huike Electric Co ltd
Priority date: 2021-09-27
Filing date: 2021-09-27
Publication date: 2022-03-08
Anticipated expiration: 2031-09-27

Abstract

The utility model provides a chopper resistance branch circuit for energy consumption, which is connected to the positive end and the negative end of a direct current transmission line and comprises an energy consumption resistor R0 and a plurality of chopper components; all the chopping assemblies are connected in series with each other and then connected in series with the energy consumption resistor R0; the chopping assembly comprises a high-speed switch T1 and a buffer circuit; the high-speed switch T1 is connected with the buffer circuit in parallel; the buffer circuit comprises a buffer diode D1, a buffer capacitor C1, a buffer resistor R1 and a buffer switch T2; the buffer switch T2 is connected in series with the buffer resistor R1, the series circuit is connected in parallel with the buffer diode D1, and the parallel circuit is connected in series with the buffer capacitor C1. The chopper resistance branch circuit for energy consumption adopts a high-power semiconductor device as a high-speed switch to directly connect in series to realize the chopper branch circuit, and the voltage of the buffer capacitor is basically stable through improving the buffer circuit of the high-speed switch with fewer devices and low cost, so that electricity can be taken from the buffer capacitor.

Description

Chopper resistor branch circuit for energy consumption

Technical Field

The utility model relates to the technical field of high-voltage direct-current power transmission, in particular to a chopper resistor branch circuit for energy consumption.

Background

Because the voltage level of the direct-current transmission system is very high, a high-speed switching technology which can bear high voltage and can be quickly switched on and off is required, which is the technical key of the chopper resistance branch circuit for energy consumption. Generally, a plurality of power semiconductor devices are connected in series to control the power semiconductor devices to be switched on and off simultaneously, so that chopping control over the energy consumption resistor is realized. In order to achieve fast control of power semiconductor devices under high voltage isolation, there are generally two schemes for supplying energy to the active parts of a high-speed switch: the high-potential part is powered by a large-power optical fiber or by high-frequency current through an isolation transformer.

The problems of high cost and large volume exist no matter high-power optical fiber is adopted for high-potential energy transmission or high-frequency current is adopted for high-potential energy transmission through an isolation transformer. Patent CN111030158A relies on energy on the buffer capacitor of the power semiconductor device to solve this problem, but in order to solve the problem that the voltage on the buffer capacitor may be 0 for a long time, a diode and a large-capacity capacitor are connected behind the buffer capacitor to store energy, and then a DC/DC converter is connected to provide power for controlling the power semiconductor device. This method requires an extra large-capacity capacitor to store energy, and the circuit is complicated.

On the other hand, in the conventional snubber circuit, when the power semiconductor device is turned on each time, energy on the snubber capacitor is completely consumed on the snubber resistor, so that the loss of the snubber resistor is remarkably increased, the design capacity of the snubber capacitor is limited, and the effect of the snubber circuit is influenced.

Another method for solving the problem of power supply of the action part of the high-speed switch is to design an energy-consuming chopping unit on the basis of a half-bridge topology or a full-bridge topology, maintain the balance of capacitor voltage in the energy-consuming chopping unit through the control of a valve control, and take power from a capacitor through a high-order energy-taking power supply to supply power. For example, patents CN109245506A, CN112187029A, CN112086948A, CN212392662U, etc. are based on half-bridge topology, while patent CN209329703U is based on full-bridge topology, and a chopper unit is designed. The chopper units designed by the methods have complex topology, more high-power semiconductor devices are required in the chopper units, and the system cost is obviously increased.

Disclosure of Invention

In order to solve the technical problems in the prior art, the utility model provides a chopper resistor branch circuit for energy consumption, which is used for preventing overvoltage at the direct current side of a direct current power transmission system.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a chopper resistance branch circuit for energy consumption is connected to the positive end and the negative end of a direct current transmission line and comprises an energy consumption resistor R0 and a plurality of chopper assemblies; all the chopping assemblies are connected in series with each other and then connected in series with the energy consumption resistor R0;

the chopper component comprises a high-speed switch T1 consisting of a turn-off power device and a buffer circuit; the high-speed switch T1 is connected with the buffer circuit in parallel;

the buffer circuit comprises a buffer diode D1, a buffer capacitor C1, a buffer resistor R1 and a buffer switch T2; the buffer switch T2 is connected in series with the buffer resistor R1, the circuit after series connection is connected in parallel with the buffer diode D1, and the circuit after parallel connection is connected in series with the buffer capacitor C1.

Further, the high-speed switch T1 is composed of a high-voltage IGBT and an anti-parallel diode thereof.

Further, the snubber switch T2 is a high voltage IGBT.

Further, all chopper modules further include a balancing resistor R2, and the balancing resistor R2 is connected in parallel across the buffer capacitor C1 or across the high-speed switch T1.

Compared with the prior art, the utility model has the beneficial effects that:

1) the circuit can realize high-speed control of the energy consumption resistor, and when the direct-current voltage of a direct-current power transmission system line is too high and the energy consumption resistor needs to be put into use, the high-speed switch T1 is switched on; when the direct current transmission system does not need to put into the energy consumption resistor, the high-speed switch T1 is switched off; at this time, all the series chopper modules bear the system direct-current voltage together, and the buffer capacitor voltage in the chopper modules is determined by the system direct-current voltage;

2) compared with the traditional RCD buffer circuit, the buffer circuit has the obvious advantages that: the current stress when the high-speed switch T1 is switched on can be remarkably reduced, and the size of the buffer capacitor C1 is not directly related to the loss of the buffer resistor R1, so that a larger buffer capacitor can be used, and the voltage overshoot when the high-speed switch T1 is switched off can be further reduced; after the high-speed switch T1 is turned on, if the voltage on the buffer capacitor C1 is too high, the buffer switch T2 can be turned on, and then the buffer capacitor will discharge through the buffer resistor R1, so as to reduce the voltage on the buffer capacitor C1;

3) the buffer circuit of the utility model realizes the maintenance of the voltage of the buffer capacitor C1 to be basically stable with fewer devices and low cost, thereby being capable of getting power from the buffer capacitor C1 and being used for controlling the power supply of a system.

Drawings

FIG. 1 is a representative implementation of the present invention;

FIG. 2 is an exemplary implementation of the chopper assembly of the present invention;

FIG. 3 is a typical implementation of the chopper assembly of the present invention, using IGBTs;

FIG. 4 is a circuit diagram of one implementation of the chopping assembly of the present invention when considering series voltage sharing;

FIG. 5 is another circuit for implementing the chopper assembly of the present invention in view of series voltage sharing;

fig. 6 is an application circuit that is considered to power the circuit board for the chopper assembly.

Detailed Description

The following detailed description of the present invention will be made with reference to the accompanying drawings.

As shown in fig. 1, a chopper resistance branch for energy consumption is connected to the positive and negative ends of a dc transmission line, and includes an energy consumption resistor R0, and two or more chopper assemblies (one chopper assembly is inside the dashed line frame in fig. 1) connected in series; all the chopping assemblies are connected in series with each other and then connected in series with the energy consumption resistor R0; the upper end of the integrated circuit after series connection is connected to the positive end of the direct current transmission line, and the lower end of the integrated circuit after series connection is connected to the negative end of the direct current transmission line.

As shown in fig. 2, each chopper assembly includes a high-speed switch T1 composed of a turn-off power device and a snubber circuit; the high-speed switch T1 is connected with the buffer circuit in parallel; the buffer circuit (the dotted-line framed part in fig. 2) includes: the buffer circuit comprises a buffer diode D1, a buffer capacitor C1, a buffer resistor R1 and a buffer switch T2; the buffer switch T2 is connected in series with the buffer resistor R1, the circuit after series connection is connected in parallel with the buffer diode D1, and the circuit after parallel connection is connected in series with the buffer capacitor C1.

As shown in fig. 3, the high-speed switch T1 is composed of a high-voltage IGBT and an anti-parallel diode thereof. The buffer switch T2 is a high-voltage IGBT.

As shown in fig. 4 to 5, in order to ensure that the buffer capacitors of all the chopper assemblies connected in series have balanced voltages when the energy dissipation resistor is not turned on, a balancing resistor R2 may be added to all the chopper assemblies. As shown in fig. 4, the balancing resistor R2 is connected in parallel across the snubber capacitor C1, and as shown in fig. 5, the balancing resistor R2 may also be connected in parallel across the high-speed switch T1.

The working principle of the utility model is explained as follows:

1) the circuit principle for realizing the high-speed control of the energy consumption resistor comprises the following steps: when the direct-current voltage of a direct-current power transmission system line is too high and the energy consumption resistor R0 needs to be put into use, the high-speed switch T1 is switched on; connecting an energy consumption resistor R0 into a direct current power transmission system line; when the direct current transmission system does not need to put into the energy consumption resistor, the high-speed switch T1 is switched off; at this time, all the series chopper modules share the system dc voltage, and the buffer capacitor voltage in the chopper modules is determined by the system dc voltage.

2) The circuit principle of the chopping assembly is as follows: when the high-speed switch T1 is switched off, the parasitic reactance on the energy consumption branch circuit generates overshoot voltage at two ends of the chopper assembly, the buffer diode D1 is conducted, and the buffer capacitor C1 clamps the voltage at two ends of the chopper assembly to avoid overvoltage. When the high speed switch T1 is turned on, with the snubber switch T2 in the off position, the voltage across the snubber capacitor C1 does not cause a transient current in T1. Therefore, compared with the traditional RCD buffer circuit, the utility model has the obvious advantages that: the current stress when the high-speed switch T1 is turned on can be significantly reduced, and the size of the snubber capacitor C1 is not directly related to the loss of the snubber resistor R1, so that a larger snubber capacitor can be used, and the voltage overshoot when the high-speed switch T1 is turned off can be further reduced. After the high-speed switch T1 is turned on, if the voltage on the buffer capacitor C1 is too high, the buffer switch T2 can be turned on, and then the buffer capacitor will discharge through the buffer resistor R1, lowering the voltage on the buffer capacitor C1.

3) In the utility model, because of the action of the buffer diode D1 in the buffer circuit, only one-way current exists in the buffer switch T2, an anti-parallel diode is not needed, and in addition, the buffer switch T2 can select an IGBT with smaller current, because the current of the IGBT is limited by the buffer resistor R1, the voltage of the buffer capacitor C1 connected with the IGBT can be maintained to be basically stable with fewer devices and lower cost, so that the electricity can be taken from the buffer capacitor C1. Fig. 6 is a circuit diagram of an embodiment for taking power from the buffer capacitor C1 to control the power supply of the circuit board.

The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the above embodiments. The methods used in the above examples are conventional methods unless otherwise specified.

Claims

1. A chopper resistance branch circuit for energy consumption is connected to two ends of a direct current transmission line and is characterized by comprising an energy consumption resistor R0 and a plurality of chopper components; all the chopping assemblies are connected in series with each other and then connected in series with the energy consumption resistor R0;

2. The chopper resistance branch for dissipating energy of claim 1, wherein the high-speed switch T1 is composed of a high-voltage IGBT and an anti-parallel diode thereof.

3. The chopper resistance branch for dissipating energy of claim 1, wherein the snubber switch T2 is a high voltage IGBT.

4. The chopper resistance branch for energy consumption of claim 1, wherein all chopper components further comprise a balancing resistor R2, and the balancing resistor R2 is connected in parallel across the snubber capacitor C1 or across the high-speed switch T1.