Bidirectional solid-state circuit breaker based on IGBT

Abstract

The bidirectional solid-state circuit breaker is composed of a power electronic switch branch circuit, two parallel energy absorption branch circuits and an overvoltage limiting branch circuit, when a short-circuit fault occurs, system current rapidly rises at a certain slope according to the size of output line inductance Llo, an electronic device switch S1 and an electronic device switch S2 start to be switched off, and the power electronic switch branch circuit and the overvoltage limiting branch circuit start to be switched off. After the electronic device switch S1 and the electronic device switch S2 are completely switched off, the fault current and the energy stored in the output line inductor Llo follow current through the parallel branch, and at the moment, the peak voltage Vds at the two ends of the electronic device switch S2 and the current flowing through the parallel energy absorption branch rise to reach the withstand voltage of the electronic device switch S2; the thyristor T1 is switched on, the fault current is consumed in the parallel branch until the fault current becomes zero, and meanwhile, the overvoltage at the two ends of the electronic device switch S2 is limited.

Description

Technical Field

[0001] The invention relates to the technical field of bidirectional solid-state circuit breakers, in particular to an IGBT-based bidirectional solid-state circuit breaker. Background Art

[0002] In modern power systems, low-voltage DC systems play an increasingly important role in industrial automation, power supply and new energy fields due to their high efficiency and high reliability. However, these systems require a protection mechanism that can quickly cut off the circuit when faced with abnormal conditions such as overload or short circuit. Although traditional mechanical circuit breakers can provide this protection, their working principle relies on mechanical movement, which not only limits their response speed, but also makes the equipment bulky and easily affected by environmental factors such as temperature and humidity changes, which in turn affects their performance and life.

[0003] To overcome these limitations, the power electronics field has been exploring more advanced circuit breaker technologies. Solid-state circuit breakers (SSCBs) have become a hot topic of research due to their advantages such as no mechanical moving parts, fast response, high reliability and long life. In particular, solid-state circuit breakers based on insulated gate bipolar transistors (IGBTs) are considered to be ideal for achieving fast and accurate overload protection of low-voltage DC systems due to their excellent switching performance and control flexibility.

[0004] As a mature power semiconductor device, IGBT has been widely used in power electronic converters due to its high-speed switching capability and low conduction loss. Applying IGBT to solid-state circuit breakers can make full use of its fast switching characteristics to achieve microsecond-level fault response, thereby significantly improving the safety of the system. In addition, the all-solid-state design eliminates mechanical components, which not only reduces the size and weight of the equipment, but also improves its adaptability to harsh environments and greatly extends the service life of the equipment.

[0005] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In view of the shortcomings or defects of the prior art, a bidirectional solid-state circuit breaker based on IGBT is provided, which can break the rated current, and absorb the fault current and the electric energy stored in the output line inductance by using the RC parallel branch. The thyristor parallel branch can limit the IGBT overvoltage while consuming electric energy. It can operate in a very short time and absorb electric energy through the parallel branch under short-circuit fault to protect itself and other components in the LVDC power distribution system.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A bidirectional solid-state circuit breaker based on IGBT consists of a power electronic switch branch, two parallel energy absorption branches and an overvoltage limiting branch, wherein the power electronic switch branch consists of two power electronic device switches S1 and an electronic device switch S2, one parallel energy absorption branch consists of a resistor R2, a capacitor C2 and a diode D2, and the other parallel energy absorption branch consists of a resistor R1, a capacitor C1 and a diode D1. The overvoltage limiting circuit consists of a resistor R3, a capacitor C3 and a thyristor T1. When the system is in normal flow, the system current flows through the power electronic switch branch. At this time, no current flows through the two parallel energy absorption branches and the overvoltage limiting branch. When a short circuit fault occurs, the system current is adjusted according to the output line inductance L. lo The size of the fault current increases rapidly with a certain slope. The electronic device switch S1 and the electronic device switch S2 begin to turn off. The fault current still increases with the same slope. After the electronic device switch S1 and the electronic device switch S2 are completely turned off, the fault current and the inductance stored in the output line L lo The energy in the circuit is continuously flowing through the parallel branch. At this time, the peak voltage V ds As well as the current flowing through the parallel energy absorption branch increases, before reaching the withstand voltage of the electronic device switch S2, the thyristor T1 is turned on, and the fault current flows through the diode D3-diode D2-capacitor C2-resistor R2 path and the diode D3-thyristor T1-capacitor C3-resistor R3-electronic device switch S2 path. In this stage, the fault current is consumed in the parallel branch until the fault current becomes 0, and the overvoltage across the electronic device switch S2 is limited.

[0009] In the IGBT-based bidirectional solid-state circuit breaker, the power electronic device switch S1 and the electronic device switch S2 are insulated gate bipolar transistors IGBTs with freewheeling diodes.

[0010] In the IGBT-based bidirectional solid-state circuit breaker, the resistor R1 is connected to the collector of the power electronic device switch S1, the resistor R2 is connected to the collector of the power electronic device switch S2, and the resistor R3 is connected to the emitters of the power electronic device switches S1 and S2.

[0011] In the IGBT-based bidirectional solid-state circuit breaker, the parallel energy-consuming branch consumes the short-circuit current through an RC circuit when a short-circuit fault occurs.

[0012] In the IGBT-based bidirectional solid-state circuit breaker, the thyristor T1 of the overvoltage limiting branch is a unidirectional semi-controlled device, and the overvoltage across the power electronic device switch S2 is limited by controlling the turn-on time of the thyristor T1.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention introduces a bypass circuit mechanism that can quickly separate the power device from the fault side when a system fault occurs. This separation is achieved through a bypass diode in the bypass circuit, which can not only safely dissipate the energy stored in the circuit through freewheeling, but also effectively clamp the peak voltage to prevent the voltage from exceeding the rated voltage level of the power device, thereby protecting the power device from damage. The design of this bypass circuit not only improves the safety of the system, but also enhances its adaptability to abnormal situations.

[0014] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0016] In the attached picture: Figure 1 It is a schematic diagram of the circuit breaker circuit topology; FIG. 2 (a) to FIG. 2 (d) are schematic diagrams of the circuit breaker switch opening and closing process of the present invention.

[0017] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0019] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0020] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0021] For a better understanding, Figure 1 As shown in FIG2 (d), a bidirectional solid-state circuit breaker based on IGBT consists of a power electronic switch branch, two parallel energy absorption branches and an overvoltage limiting branch, wherein the power electronic switch branch consists of two power electronic device switches S1 and an electronic device switch S2, one parallel energy absorption branch consists of a resistor R2, a capacitor C2 and a diode D2, and the other parallel energy absorption branch consists of a resistor R1, a capacitor C1 and a diode D1. The overvoltage limiting circuit consists of a resistor R3, a capacitor C3 and a thyristor T1. When the system is in normal flow, the system current flows through the power electronic switch branch. At this time, no current flows through the two parallel energy absorption branches and the overvoltage limiting branch. When a short circuit fault occurs, the system current flows according to the output line inductance L. lo The size of the fault current increases rapidly with a certain slope. The electronic device switch S1 and the electronic device switch S2 begin to turn off. The fault current still increases with the same slope. After the electronic device switch S1 and the electronic device switch S2 are completely turned off, the fault current and the inductance stored in the output line L lo The energy in the circuit is continuously flowing through the parallel branch. At this time, the peak voltage V ds As well as the current flowing through the parallel energy absorption branch increases, before reaching the withstand voltage of the electronic device switch S2, the thyristor T1 is turned on, and the fault current flows through the diode D3-diode D2-capacitor C2-resistor R2 path and the diode D3-thyristor T1-capacitor C3-resistor R3-electronic device switch S2 path. In this stage, the fault current is consumed in the parallel branch until the fault current becomes 0, and the overvoltage across the electronic device switch S2 is limited.

[0022] In a preferred embodiment of the IGBT-based bidirectional solid-state circuit breaker, the power electronic device switch S1 and the electronic device switch S2 are insulated gate bipolar transistors IGBTs with freewheeling diodes.

[0023] In a preferred embodiment of the IGBT-based bidirectional solid-state circuit breaker, resistor R1 is connected to the collector of the power electronic device switch S1, resistor R2 is connected to the collector of the power electronic device switch S2, and resistor R3 is connected to the emitters of the power electronic device switches S1 and S2.

[0024] In a preferred embodiment of the IGBT-based bidirectional solid-state circuit breaker, the parallel energy-consuming branch consumes the short-circuit current through an RC circuit when a short-circuit fault occurs.

[0025] In a preferred embodiment of the IGBT-based bidirectional solid-state circuit breaker, the thyristor T1 of the overvoltage limiting branch is a unidirectional semi-controlled device, and the overvoltage across the power electronic device switch S2 is limited by controlling the on-time of the thyristor T1.

[0026] In one embodiment, the IGBT-based bidirectional solid-state circuit breaker includes a power electronic switch branch, a parallel energy consumption branch, and an overvoltage limiting circuit. The breaking process is as follows.

[0027] (1) If Figure 1 As shown, when the system is in normal flow state, the current flows through the power electronic switch branch, and S1S2 remains in the on state.

[0028] (2) As shown in Figure 2(b), S1 and S2 begin to turn off, and the fault current continues to rise at a certain slope.

[0029] (3) As shown in Figure 2(c), S1 and S2 are turned off, and the fault current and the current stored in L lo The energy in the circuit is continued through the parallel branches R2, C2, D2 and D3. At this time, the peak voltage V ds And the current I flowing through the parallel branch R3 R3 Will all rise.

[0030] (4) T1 is turned on, and the fault current flows through the D3-D2-C2-R2 path and the D3-T1-C3-R3-S2 path. In this stage, the fault current is rapidly consumed in the parallel branch until the fault current becomes 0 and the circuit breaker completes the current cutoff.

[0031] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0032] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A bidirectional solid-state circuit breaker based on IGBT, It is characterized in that It consists of a power electronic switch branch, two parallel energy absorption branches and an overvoltage limiting branch, wherein the power electronic switch branch has two power electronic device switches S 1 and electronic device switch S 2 A parallel energy absorption branch is composed of a resistor R 2 , capacitor C 2 and diode D 2 The other parallel energy absorption branch is composed of resistor R 1 , capacitor C 1 and diode D 1 The overvoltage limiting circuit consists of a resistor R 3 , capacitor C 3 and thyristor T 1 When the system is in normal flow condition, the system current flows through the power electronic switch branch. At this time, no current flows through the two parallel energy absorption branches and one overvoltage limiting branch. When a short circuit occurs, the system current is proportional to the output line inductance L. lo The size of the electronic device switches S 1 and electronic device switch S 2 The fault current continues to rise at the same slope, and the electronic device switch S 1 and electronic device switch S 2 After complete shutdown, the fault current and the current stored in the output line inductance L lo The energy in the circuit is continuously flowing through the parallel branch. At this time, the electronic device switch S 2 The peak voltage V ds And the current flowing through the parallel energy absorption branch increases, reaching the electronic device switch S 2 Before withstand voltage, thyristor T 1 The fault current flows through the diode D 3 – Diode D 2 – Capacitor C 2 – Resistor R 2 Path and diode D 3 -Thyristor T 1 -Capacitor C 3 -Resistor R 3 -Electronic device switch S 2 In this stage, the fault current is consumed in the parallel branch until the fault current becomes 0, and the electronic device switch S 2 The overvoltage at both ends is limited.

2. The IGBT-based bidirectional solid-state circuit breaker according to claim 1, It is characterized in that Preferably, the power electronic device switch S 1 and electronic device switch S 2 It is an insulated gate bipolar transistor IGBT with a freewheeling diode.

3. The IGBT-based bidirectional solid-state circuit breaker according to claim 1, It is characterized in that Resistor R 1 Connect the power electronic device switch S 1 The collector resistor R 2 Connect the power electronic device switch S 2 The collector resistor R 3 Connect the power electronic device switch S 1 and S 2 of the emitter.

4. The IGBT-based bidirectional solid-state circuit breaker according to claim 1, It is characterized in that When a short-circuit fault occurs, the parallel energy-consuming branch consumes the short-circuit current through an RC circuit.

5. The IGBT-based bidirectional solid-state circuit breaker according to claim 1, It is characterized in that The thyristor T of the overvoltage limiting branch 1 It is a unidirectional half-controlled device, and by controlling the thyristor T 1 Opening time limit power electronic device switch S 2 Overvoltage at both ends.

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