阅读说明：本技术 一种基于耦合电感的固态直流断路器 (Solid-state direct current breaker based on coupling inductance ) 是由 吴益飞 吴翊 荣命哲 杨飞 易强 肖宇 于 2020-06-01 设计创作，主要内容包括：本公开揭示了一种基于耦合电感的固态断路器,包括：N条并联连接的载流支路、缓冲支路和耗能支路,所述N条并联连接的载流支路和缓冲支路及耗能支路依次并联；其中,所述N条并联连接的载流支路中,每条载流支路均包括串联连接的电力电子器件、第一电感线圈和第二电感线圈；每条载流支路中的电感线圈和其相邻载流支路中的电感线圈异名端连接,构成耦合线圈。本公开通过在固态直流断路器中引入耦合电感,能够有效抑制各并联支路中电力电子器件的动静态电流分配不均的问题,避免器件出现过电流损坏的现象,保护及延长电力电子器件的使用寿命,有利于固态直流断路器的可靠关断。(The present disclosure discloses a solid state circuit breaker based on coupled inductors, including: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; each current-carrying branch circuit comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series; the induction coil in each current-carrying branch is connected with the synonym end of the induction coil in the adjacent current-carrying branch to form a coupling coil. According to the solid-state direct current circuit breaker, the coupling inductor is introduced into the solid-state direct current circuit breaker, the problem that dynamic and static currents of power electronic devices in each parallel branch circuit are distributed unevenly can be effectively solved, the phenomenon that the devices are damaged by over-current is avoided, the service life of the power electronic devices is protected and prolonged, and reliable turn-off of the solid-state direct current circuit breaker is facilitated.)

1. A coupled inductance based solid state dc circuit breaker comprising: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; wherein the content of the first and second substances,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when the number of N is an odd number,

a first inductance coil in the first current-carrying branch is connected with a first inductance coil synonym end in the second current-carrying branch to form a coupling coil;

the second inductance coil in the first current-carrying branch is connected with the synonym end of the first inductance coil in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

a first inductance coil in the third current-carrying branch circuit is connected with a first inductance coil synonym end in the fourth current-carrying branch circuit to form a coupling coil;

by analogy, the second inductance coil in the N-1 current-carrying branch is connected with the synonym end of the second inductance coil in the N current-carrying branch to form a coupling coil.

2. A coupled inductance based solid state dc circuit breaker comprising: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; among them, it is preferable that,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when N is an even number, the number of bits in the bit line is,

a first inductance coil in the first current-carrying branch is connected with a first inductance coil synonym end in the second current-carrying branch to form a coupling coil;

a second inductance coil in the first current-carrying branch is connected with a second inductance coil synonym end in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

a first inductance coil in the third current-carrying branch circuit is connected with a first inductance coil synonym end in the fourth current-carrying branch circuit to form a coupling coil;

by analogy, the first inductance coil in the N-1 current-carrying branch is connected with the synonym end of the first inductance coil in the N current-carrying branch to form a coupling coil.

3. The solid state dc circuit breaker according to claim 1 or 2, wherein the solid state dc circuit breaker comprises N current carrying branches, N snubber branches and a power dissipating branch, wherein of the N current carrying branches, each current carrying branch comprises power electronics, a first inductor winding and a second inductor winding, and wherein the power electronics in each current carrying branch is connected in parallel with one snubber branch and then with the power dissipating branch.

4. The solid state dc circuit breaker according to claim 1 or 2, wherein the solid state dc circuit breaker comprises N current carrying branches, N snubber branches and N energy dissipating branches, wherein of the N current carrying branches, each current carrying branch comprises power electronics, a first inductor winding and a second inductor winding, and wherein the power electronics in each current carrying branch is connected in parallel with one snubber branch and one energy dissipating branch.

5. The solid-state direct current breaker according to claim 1 or 2, wherein when the current flowing through the power electronic device is unbalanced, an induced electromotive force is generated on the coupling coil, the induced electromotive force of the current carrying branch with large current is negative, the induced electromotive force of the current carrying branch with small current is positive, and magnetic energy and electric energy are mutually converted, so that the current flowing through the current carrying branches connected in parallel is balanced.

6. Solid state direct current circuit breaker according to claim 1 or 2, wherein the inductance values of the induction coils in the current carrying branches are equal.

7. The solid state direct current circuit breaker according to claim 1 or 2, wherein the snubber branch comprises any one of the following structures:

a buffer capacitor;

the buffer resistor and the buffer capacitor are connected in series;

the buffer resistor and the diode are connected in parallel and then connected in series with the buffer capacitor.

8. Solid state direct current circuit breaker according to claim 1 or 2, wherein the energy consuming branch comprises an arrester.

9. The solid state direct current circuit breaker of claim 8, wherein the surge arrester comprises any one of: the lightning arrester comprises a line type metal oxide lightning arrester, a gapless line type metal oxide lightning arrester, a full-insulation composite jacket metal oxide lightning arrester and a detachable lightning arrester.

10. Solid state direct current circuit breaker according to claim 1 or 2, wherein the power electronics comprises any of: IGBT, IEGT, GTO, IGCT.

Technical Field

The present disclosure relates to a current sharing method for parallel power electronic devices, and more particularly, to a solid-state dc circuit breaker based on coupled inductors.

Background

Compared with an alternating current power grid, the direct current power grid has the advantages of few conversion links, high energy utilization rate, good power flow control degree, low line cost, high active power, high regulation speed and the like, and is an important direction for developing a future intelligent power grid. In addition, the development of the multi-terminal flexible direct-current transmission technology provides an effective solution for the inherent defects of dispersibility, miniaturization, load center distance and the like of renewable clean energy sources such as wind energy, solar energy and the like.

However, the direct current system has a high current rise rate after a short-circuit fault occurs, the fault propagation speed is high, and the collapse of the power grid is easily caused by timely fault removal, so that the direct current circuit breaker is required to have the characteristics of high breaking speed and strong breaking capacity. The traditional mechanical dc circuit breaker is difficult to meet the requirement for breaking speed, and with the continuous development of high-power semiconductor technology, a solid-state dc circuit breaker which mainly depends on power electronic devices to complete current breaking gradually becomes a research hotspot in the field of dc breaking and breaking. The solid-state direct current circuit breaker mainly comprises high-power electronic devices such as an IGCT (integrated gate commutated thyristor), an IGBT (insulated gate bipolar transistor), an IEGT (injection enhanced gate transistor), a buffer protection branch circuit and an energy consumption branch circuit, and because the turn-off capability of a single power electronic device is limited, the devices need to be connected in series and in parallel to meet the turn-off requirement of the circuit breaker. However, due to the influence of factors such as dispersion of device parameters of different power electronic devices, unequal junction temperature of devices, asymmetric structure of components and the like, the power electronic devices of different parallel branches have the problem of unbalanced current, which includes: the quiescent current after turn-on is unbalanced and the dynamic current during the switching transient state is unbalanced. The unbalanced current not only wastes the device capacity, but also causes unequal loss among devices and switching speed, voltage and current stress, and even causes the damage of the devices due to the overshooting electrical stress, thereby affecting the reliable turn-off of the solid-state dc circuit breaker.

Disclosure of Invention

Aiming at the defects in the prior art, the disclosed solid-state direct current circuit breaker based on coupling inductors is provided, coupling inductors connected with different name ends are introduced into each branch of the parallel power electronic devices of the solid-state direct current circuit breaker, a magnetic field is used as a medium, energy is converted, and current is transferred, so that the problem of unbalanced current distribution among the parallel power electronic devices of each branch can be solved.

In order to achieve the above purpose, the present disclosure provides the following technical solutions:

a coupled inductance based solid state dc circuit breaker comprising: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; wherein the content of the first and second substances,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when the number of N is an odd number,

a first inductance coil in the first current-carrying branch is connected with a first inductance coil synonym end in the second current-carrying branch to form a coupling coil;

the second inductance coil in the first current-carrying branch is connected with the synonym end of the first inductance coil in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

a first inductance coil in the third current-carrying branch circuit is connected with a first inductance coil synonym end in the fourth current-carrying branch circuit to form a coupling coil;

by analogy, the second inductance coil in the N-1 current-carrying branch is connected with the synonym end of the second inductance coil in the N current-carrying branch to form a coupling coil.

A coupled inductance based solid state dc circuit breaker comprising: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; wherein the content of the first and second substances,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when N is an even number, the number of bits in the bit line is,

a first inductance coil in the first current-carrying branch is connected with a first inductance coil synonym end in the second current-carrying branch to form a coupling coil;

a second inductance coil in the first current-carrying branch is connected with a second inductance coil synonym end in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

a first inductance coil in the third current-carrying branch circuit is connected with a first inductance coil synonym end in the fourth current-carrying branch circuit to form a coupling coil;

by analogy, the first inductance coil in the N-1 current-carrying branch is connected with the synonym end of the first inductance coil in the N current-carrying branch to form a coupling coil.

Preferably, the solid-state dc circuit breaker includes N current-carrying branches, N buffer branches, and an energy-consuming branch, wherein each current-carrying branch of the N current-carrying branches includes a power electronic device, a first inductance coil, and a second inductance coil, and the power electronic device of each current-carrying branch is connected in parallel with one buffer branch and then connected in parallel with the energy-consuming branch.

Preferably, the solid-state dc circuit breaker includes N current-carrying branches, N buffer branches, and N energy-consuming branches, wherein each current-carrying branch of the N current-carrying branches includes a power electronic device, a first inductance coil, and a second inductance coil, and the power electronic device of each current-carrying branch is connected in parallel with one buffer branch and one energy-consuming branch.

Preferably, when the current flowing through the power electronic device is unbalanced, induced electromotive force is generated on the coupling coil, the induced electromotive force of the current carrying branch with large current is negative, the induced electromotive force of the current carrying branch with small current is positive, and magnetic energy and electric energy are mutually converted, so that the current flowing through the current carrying branches connected in parallel is balanced.

Preferably, the inductance values of the inductors in the current carrying branches are equal.

Preferably, the buffering branch comprises any one of the following structures:

a buffer capacitor;

the buffer resistor and the buffer capacitor are connected in series;

the buffer resistor and the diode are connected in parallel and then connected in series with the buffer capacitor.

Preferably, the energy consumption branch comprises an arrester.

Preferably, the arrester comprises any one of: the lightning arrester comprises a line type metal oxide lightning arrester, a gapless line type metal oxide lightning arrester, a full-insulation composite jacket metal oxide lightning arrester and a detachable lightning arrester.

Preferably, the power electronic device includes any one of: IGBT, IEGT, GTO, IGCT.

Compared with the prior art, the beneficial effect that this disclosure brought does: according to the solid-state direct current circuit breaker, the coupling inductor is introduced into the solid-state direct current circuit breaker, the problem that dynamic and static currents of power electronic devices in each parallel branch circuit are distributed unevenly can be effectively solved, the phenomenon that the devices are damaged by over-current is avoided, the service life of the power electronic devices is protected and prolonged, and reliable turn-off of the solid-state direct current circuit breaker is facilitated.

Drawings

Fig. 1(a) to fig. 1(b) are schematic structural diagrams of a solid-state dc circuit breaker based on coupled inductors according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a solid-state dc circuit breaker based on coupled inductors according to another embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a solid-state dc circuit breaker based on coupled inductors according to another embodiment of the present disclosure;

fig. 4 is a schematic diagram of current distribution of parallel power electronic devices during turn-off of a solid-state dc circuit breaker without introduction of a coupling inductor according to another embodiment of the present disclosure;

fig. 5 is a schematic diagram of current distribution of parallel power electronics during turn-off of a solid-state dc circuit breaker incorporating a coupled inductor according to another embodiment of the present disclosure;

fig. 6(a) to 6(c) are schematic diagrams of internal circuits of buffer branches according to another embodiment of the present disclosure.

Detailed Description

Specific embodiments of the present disclosure will be described in detail below with reference to fig. 1(a) to 6 (c). While specific embodiments of the disclosure are shown in the drawings, it should be understood that the disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be noted that certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, but is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present disclosure is to be determined by the terms of the appended claims.

To facilitate an understanding of the embodiments of the present disclosure, the following detailed description is to be considered in conjunction with the accompanying drawings, and the drawings are not to be construed as limiting the embodiments of the present disclosure.

In one embodiment, the present disclosure provides a coupled inductance based solid state dc circuit breaker, comprising: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; wherein the content of the first and second substances,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when the number of N is an odd number,

a first inductance coil in the first current-carrying branch is connected with a first inductance coil synonym end in the second current-carrying branch to form a coupling coil;

the second inductance coil in the first current-carrying branch is connected with the synonym end of the first inductance coil in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

a first inductance coil in the third current-carrying branch circuit is connected with a first inductance coil synonym end in the fourth current-carrying branch circuit to form a coupling coil;

by analogy, the second inductance coil in the N-1 current-carrying branch is connected with the synonym end of the second inductance coil in the N current-carrying branch to form a coupling coil.

In this embodiment, as shown in fig. 1(a), when the current-carrying branches are odd, the first inductor L in the first current-carrying branch₁₁And a first inductance coil L in a second current-carrying branch₂₁The different name ends are connected to form a coupling coil; second inductance coil L in first current-carrying branch₁₂And a first inductance coil L in a second current-carrying branch N_N1The different name ends are connected to form a coupling coil; second inductor L in a second current-carrying branch₂₂And a second inductance coil L in a third current-carrying branch₃₂The different name ends are connected to form a coupling coil; first inductance coil L in third current-carrying branch₃₁And a first inductance coil L in a fourth current-carrying branch₄₁And the different name ends are connected to form a coupling coil, and in the same way, the different name ends of the second inductance coil in the N-1 current-carrying branch and the second inductance coil in the N current-carrying branch are connected to form the coupling coil.

FIG. 4 is a schematic diagram of the current distribution of the parallel power electronic devices during the turn-off process of the solid-state DC circuit breaker without the introduction of the coupling inductor, as shown in FIG. 4, when the solid-state DC circuit breaker opens the current, the two power electronic devices are controlledPower electronic device IGBT in parallel current-carrying branch₁、IGBT₂And turning off the circuit, and transferring the current to the buffer branch circuit. However, due to the influence of the dispersion of device parameters of different power electronic devices, unequal junction temperatures of the devices, asymmetric component structures and other factors, the IGBT can flow through the two power electronic devices₁、IGBT₂Current i of_G1、i_G2The current distribution is not uniform. During turn-off, flows through the power electronics IGBT₁Current i of_G1Will rise a certain amplitude and then reduce in the turn-off process, resulting in the IGBT device₁Can bear the current stress of overshoot for a short time, can cause the over-current damage of the device, and influence the reliable turn-off of the solid-state direct current breaker.

Fig. 5 is a schematic diagram of current distribution of parallel power electronic devices in the turn-off process of a solid-state dc circuit breaker with a coupled inductor, as shown in fig. 5, when two power electronic devices IGBT are used, by introducing a coupling coil with a different name end connected in each parallel current-carrying branch of the solid-state dc circuit breaker₁、IGBT₂Current i of_G1、i_G2When the current distribution is uneven, the total magnetic flux generated by the coupling coil is not zero, so that induced electromotive force is generated on the coupling coil. Power electronic device IGBT₁Current i of_G1IGBT larger than power electronic device₂Current i of_G2So as to be applied to the IGBT of the power electronic device₁Generating induced electromotive force with negative polarity in the branch, and generating negative voltage in the power electronic device IGBT₂The induced electromotive force with positive polarity is generated in the branch, so that the non-uniform current state of the two power electronic devices is improved.

In another embodiment, the present disclosure further provides a solid-state dc circuit breaker based on coupled inductors, including: the energy-saving device comprises N current-carrying branches, a buffer branch and an energy-consuming branch which are connected in parallel, wherein the N current-carrying branches, the buffer branch and the energy-consuming branch which are connected in parallel are sequentially connected in parallel; wherein the content of the first and second substances,

each current-carrying branch comprises a power electronic device, a first inductance coil and a second inductance coil which are connected in series;

when N is an even number, the number of bits in the bit line is,

the first inductance coil in the first current-carrying branch is connected with the synonym end of the first inductance coil in the second current-carrying branch to form a coupling coil;

the second inductance coil in the first current-carrying branch is connected with the synonym end of the second inductance coil in the Nth current-carrying branch to form a coupling coil;

a second inductance coil in the second current-carrying branch is connected with a second inductance coil synonym end in the third current-carrying branch to form a coupling coil;

the first inductance coil in the third current-carrying branch is connected with the synonym end of the first inductance coil in the fourth current-carrying branch to form a coupling coil;

by analogy, the first inductance coil in the N-1 current-carrying branch is connected with the synonym end of the first inductance coil in the N current-carrying branch to form a coupling coil.

In this embodiment, as shown in fig. 1(b), when the current-carrying branches are even numbers, the first inductance coil L in the first current-carrying branch is₁₁And a first inductance coil L in a second current-carrying branch₂₁The different name ends are connected to form a coupling coil; second inductance coil L in first current-carrying branch₁₂And a second inductance coil L in a second current-carrying branch N_N1The different name ends are connected to form a coupling coil; second inductor L in a second current-carrying branch₂₂And a second inductance coil L in a third current-carrying branch₃₂The different name ends are connected to form a coupling coil; first inductance coil L in third current-carrying branch₃₁And a first inductance coil L in a fourth current-carrying branch₄₁And the different name ends are connected to form a coupling coil, and in the same way, the different name ends of the first inductance coil in the N-1 current-carrying branch and the first inductance coil in the N current-carrying branch are connected to form the coupling coil.

The 2 embodiments can solve the problem of unbalanced current distribution among the power electronic devices in the parallel current-carrying branch, thereby improving the power utilization rate of the power electronic devices, prolonging the service life of the power electronic devices and ensuring the reliable breaking of the solid-state direct-current circuit breaker.

In another embodiment, the solid-state dc circuit breaker shown in fig. 1(a) to 1(b) may further be modified as shown in fig. 2, where the solid-state dc circuit breaker includes N current-carrying branches, N buffer branches, and energy-consuming branches, each current-carrying branch of the N current-carrying branches includes a power electronic device, a first inductance coil, and a second inductance coil, and the power electronic device in each current-carrying branch is connected in parallel with one buffer branch and then connected in parallel with the energy-consuming branch.

In this embodiment, as shown in fig. 2, the power electronic device is an IGBT, the snubber branch is formed by a snubber resistor R and a snubber capacitor C connected in series, and the snubber resistor R and the snubber capacitor C are connected in series and then connected in parallel with the IGBT. In the configuration shown in fig. 2, the power electronic device is not limited to the IGBT, and may be replaced with any one of the IEGT, GTO, and IGCT, for example. The buffer branch may also adopt other structures, as shown in fig. 6(a) to 6(C), may only include the buffer capacitor C, or may be formed by connecting the buffer resistor R and the diode D in parallel and then connecting the buffer capacitor C in series.

In another embodiment, the solid-state circuit breaker shown in fig. 1(a) to 2 may be further modified, as shown in fig. 3, the solid-state dc circuit breaker includes N current-carrying branches, N buffer branches, and N energy-consuming branches, each current-carrying branch of the N current-carrying branches includes a power electronic device, a first inductance coil, and a second inductance coil, and the power electronic device of each current-carrying branch is connected in parallel with one buffer branch and one energy-consuming branch.

In this embodiment, the type selection of the power electronic device and the structural transformation of the buffer branch are the same as those in the foregoing embodiments, and are not described herein again.

In another embodiment, the inductance values of the inductors in the current carrying branches are equal.

In this embodiment, if the inductance values of the inductor coils are not equal, when the current-carrying branches are in a current-sharing state, the magnitude of the magnetic flux generated on the coupling coil is not equal, the total magnetic flux generated is not 0, and the current is unbalanced.

The foregoing describes the general principles of the present disclosure in conjunction with specific embodiments, however, it is noted that the advantages, effects, etc. mentioned in the present disclosure are merely examples and are not limiting, and they should not be considered essential to the various embodiments of the present disclosure. Furthermore, the foregoing disclosure of specific details is for the purpose of illustration and description and is not intended to be limiting, since the foregoing disclosure is not intended to be exhaustive or to limit the disclosure to the precise details disclosed.