CN211655738U

CN211655738U - Medium-high voltage bidirectional full-solid-state direct current circuit breaker

Info

Publication number: CN211655738U
Application number: CN201922232789.4U
Authority: CN
Inventors: 施小东; 陈鹏; 施秦峰; 祝建军; 郑立成
Original assignee: Zhejiang Doway Advanced Technology Co ltd
Current assignee: Zhejiang Doway Advanced Technology Co ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-10-09
Anticipated expiration: 2029-12-13

Abstract

The utility model provides a possess heavy current excision ability, system cost can not increase by a wide margin, but two-way through-flow's two-way solid state direct current circuit breaker entirely of medium and high voltage belongs to direct current medium and high voltage electric appliance field. The fault current protection circuit comprises a mechanical isolating switch, a current-limiting inductor, a rated current path branch and a fault current removing branch. The rated current path branch circuit is connected with the fault current cutting branch circuit in parallel; the rated current path branch comprises a power electronic switch assembly and an IGBT assembly which are connected in series, the power electronic switch assembly is formed by connecting a plurality of groups of thyristor units in series, and the fault current removing branch comprises a plurality of groups of IGBT units in series. The IGBT unit is of a full-bridge bidirectional through-current topological structure, so that bidirectional current circulation can be realized, and the through-current capacity of fault current can be doubled.

Description

Medium-high voltage bidirectional full-solid-state direct current circuit breaker

Technical Field

The utility model belongs to high voltage electrical apparatus field in the direct current, concretely relates to two-way full solid state direct current circuit breaker of well high voltage and high potential energy supply device thereof.

Background

In the field of direct current power distribution such as ships, airplanes, direct current power grids, multi-terminal direct current transmission, and the like, a voltage source type rectifying/inverting device is often adopted. The existing direct current circuit breakers are mainly divided into mechanical direct current circuit breakers, all-solid-state direct current circuit breakers and hybrid direct current circuit breakers, the mechanical direct current circuit breakers adopt mechanical switches to cut off direct current, the turn-off capacity is high, however, an artificial zero crossing point needs to be created, an arc extinguishing working point is difficult to accurately grasp, the repeatability is poor, the turn-off time needs dozens of milliseconds, the mechanical stroke is long, and the technical requirements of a direct current power grid cannot be met. The hybrid direct current circuit breaker combines a mechanical switch and a power electronic device, has the advantages of small on-state loss and no arc discharge, but has a complex structure and a large volume, and the cutting time of fault current is several milliseconds, so that the peak value of the fault current is large, and the application requirements of certain special industries are difficult to meet. The all-solid-state direct current breaker directly breaks direct current by using a high-power semiconductor device, has short breaking time and no electric arc, but has large on-state loss and high cost.

The defects of large on-state loss and high cost of the all-solid-state direct current circuit breaker in the prior art are overcome. The novel all-solid-state direct current circuit breaker is low in on-state loss, high in turn-off speed, good in consistency and voltage-sharing effect of series power electronic devices, and capable of reliably absorbing turn-off overvoltage and energy, for example, the patent authorization publication number is CN104242265B, the patent name is a direct current distribution network all-solid-state direct current circuit breaker, and the main circuit structure of the circuit breaker is that the direct current circuit breaker is formed by connecting an auxiliary circuit breaker loop, a main circuit breaker loop and an energy absorption loop in parallel. The auxiliary circuit breaker loop comprises a thyristor switch unit and a modular full-control device switch unit which are connected in series; the main circuit breaker loop comprises a plurality of press-mounting full-control device switch units, an arrester and a fuse, and bidirectional through-flow is realized by adopting a diode bridge structure; the energy absorbing circuit includes at least one arrester. The utility model discloses a full solid-state direct current breaker topological structure who constitutes is novel, and the function is comprehensive, and the on-state loss is lower during normal operating, can detect current state rapidly and effective discernment trouble, can realize breaking two-way electric current during the trouble, and the shutoff current level is high, and the trouble is clear away fastly, and the overvoltage and the energy absorption of shutoff in-process are effectual, effectively restrict the fault current rate of rise, carry out reliable protection to main circuit breaker return circuit series connection valves and auxiliary circuit breaker return circuit full control device. But the fuse is also used for cutting off the fault current under the condition of serious large-current fault so as to protect the valve group device from being damaged.

Disclosure of Invention

The utility model discloses to the drawback that can't cut off heavy current trouble among the prior art, provide and possess heavy current excision ability, system's cost can not increase by a wide margin, can two-way through-flow a two-way all solid state direct current breaker of well high pressure and high potential energy supply device thereof.

According to one aspect of the utility model, a medium-high voltage bidirectional full-solid-state direct current circuit breaker is provided, which comprises a mechanical isolating switch, a current-limiting inductor, a rated current path branch and a fault current cutting branch, wherein the rated current path branch is connected with the fault current cutting branch in parallel; the rated current path branch comprises a power electronic switch component and an IGBT component which are connected in series, the power electronic switch component is formed by connecting a plurality of groups of thyristor units in series, and each group of thyristor units is formed by connecting a forward thyristor, a direct current voltage-sharing branch, a dynamic voltage-sharing branch and a reverse thyristor in parallel; the IGBT component is formed by connecting a plurality of groups of IGBT units in parallel; the fault current cutting branch circuit is formed by connecting a plurality of groups of IGBT units in series; the IGBT unit comprises a full-bridge IGBT module bidirectional through-flow branch and an energy absorption branch, the full-bridge IGBT module bidirectional through-flow branch is connected with the energy absorption branch in parallel, a bridge arm of the IGBT module bidirectional through-flow branch is an IGBT module, and two ends of the IGBT module are connected with an RCD protection absorption branch and a direct-current equalizing resistor.

In the scheme, the mechanical isolating switch is used for isolating a power supply, a circuit without load current is disconnected, arc extinguishing capacity is avoided, the current-limiting inductor is used for inhibiting transient current, and the inhibiting effect on the current with the higher change rate is more obvious. The inductance value depends on the requirements of stable operation of the system. Normally, the rated current path branch carries the entire load current and is always in the on state. Because the on-state voltage drop of the power electronic switch assembly and the IGBT assembly is small, the loss of the direct current circuit breaker is low, and the overall operation efficiency of a power supply system cannot be influenced. Once the main loop is short-circuited or the fault current is increased, the series IGBT unit of the fault current cutting-off branch circuit is immediately triggered and conducted, then the parallel IGBT unit of the rated current access branch circuit enters a turn-off state, the current starts to transfer to the fault current cutting-off branch circuit, after the thyristor current of the power electronic switch assembly is reduced to zero, the power electronic switch assembly also enters the turn-off state, and the power electronic switch assembly has the capacity of bearing high voltage due to the characteristics of the thyristor. The direct current voltage-sharing branch and the dynamic voltage-sharing branch of the thyristor unit are connected in parallel with the thyristor, so that the rising speed of the voltage at two ends of the thyristor is slowed down, and the loss of devices is reduced. After the fault current is transferred to the fault current cutting branch circuit, the series IGBT unit of the fault current cutting branch circuit enters a turn-off state, because the current in the main loop is large, the energy stored on the current-limiting inductor is large, the arc energy cannot disappear immediately, and the energy absorption branch circuit of the series IGBT unit of the fault current cutting branch circuit starts to absorb and discharge the energy. The IGBT modules are insulated gate bipolar transistor modules, and the design of the full-bridge IGBT module bidirectional through-current branch enables the upper and lower groups of IGBT modules to bear half of load current respectively, so that the short-circuit fault breaking current capacity is doubled, and the high-current cutting capacity is achieved. The RCD protection absorbing branch circuit connected with the two ends of the IGBT module can slow down the rising speed of the voltage when the IGBT module is turned off, reduces turn-off loss, more quickly discharges residual energy in a system, and the direct-current equalizing resistor ensures that the voltage drops born by the two ends of the IGBT module of each IGBT unit are basically the same and can help discharge electric energy.

Preferably, the IGBT module is a crimp type IGBT module. Compared with the traditional welding type IGBT, the compression joint type IGBT utilizes pressure to realize thermodynamic and electrical connection and ensures double-sided heat dissipation. The power cycle capability of the crimping type IBGT device is very strong and is far superior to that of a welding type IGBT module.

Preferably, the thyristor assembly comprises a plurality of groups of thyristor cells. The more the thyristor units are connected in series, the stronger the high voltage resistance of the thyristor assembly. The thyristor switch has the advantages of small on-state resistance, m omega level, high withstand voltage of about 8kV, short turn-off time which is about one percent of that of a mechanical switch, short fault current removal time, small short-circuit current peak value, greatly reduced arc extinguishing energy and low price, and the system cost cannot be greatly increased by taking the thyristor component as the overcurrent cutoff of the circuit breaker.

Preferably, the energy absorption branch is formed by connecting a direct current capacitor and an MOV zinc oxide arrester in parallel. When residual electric energy in the circuit charges the direct current capacitor, if the voltage insulation at the two ends of the direct current capacitor is matched horizontally, the MOV zinc oxide arrester acts to quickly discharge the electric energy, and the IGBT unit is protected from being damaged.

Preferably, the RCD protection absorption branch includes a diode, a resistor, and a dc capacitor, and the resistor is connected in parallel with the diode and then connected in series with the dc capacitor. The RCD protection absorption branch can slow down the voltage rising speed when the IGBT module is turned off, and turn-off loss is reduced.

According to another aspect of the present invention, a high potential energy supply device is provided, which comprises a PMW pulse width modulation rectification circuit, a filter capacitor, a full bridge inverter circuit, a resonant capacitor assembly, a magnetic ring transformer, a full bridge rectifier diode assembly, a high voltage energy storage filter capacitor, a bleed-off resistor, and a dc voltage converter; the PMW pulse width modulation rectification circuit, the filter capacitor and the full-bridge inverter circuit are connected in parallel in sequence; the PMW pulse width modulation rectification circuit comprises a three-phase half-bridge circuit consisting of an inductor at an alternating current side and an IGBT module; the bridge arm of the full-bridge inverter circuit is an IGBT module; the output end of the full-bridge inverter circuit is connected with the input end of the resonant capacitor component; the output end of the resonant capacitor component is connected with a primary loop of the magnetic loop transformer, and leakage inductance of the resonant capacitor component and the magnetic loop transformer form an LCC series-parallel resonant circuit. The secondary circuit of the magnetic ring transformer is connected with the input end of the full-bridge rectifier diode component, the high-voltage energy storage filter capacitor and the bleeder resistor are connected in parallel in sequence, and the output end of the bleeder resistor is connected with the direct-current voltage converter.

In the scheme, the PMW pulse width modulation rectification circuit rectifies three-phase alternating current into direct current, the direct current passes through the filter capacitor and then passes through the full-bridge inverter circuit, the resonance occurs through the leakage inductance of the resonance capacitor component and the magnetic ring transformer, high-frequency pulse electric energy on a low-voltage side is converted to a high-voltage side, the full-bridge rectifier diode component rectifies the direct current to form stable high-voltage direct current voltage, and the stable high-voltage direct current voltage is converted into a switch driving power supply required by the IGBT module through the direct current. The number of the magnetic ring transformer, the full-bridge rectifier diode assembly, the high-voltage energy storage filter capacitor, the bleeder resistor and the direct-current voltage converter is consistent with the number of the IGBT modules in the full-solid-state direct-current circuit breaker. The power supply of the device is three-phase alternating current, and is supplied with power separately from the direct current power supply passing through the all-solid-state direct current circuit breaker, so that the isolation is well performed, the influence of the fault current of the all-solid-state direct current circuit breaker is avoided, and the stability of the control power supply when the fault current occurs in the solid-state direct current circuit breaker is ensured; the power supplies after the transformation of each transformer are mutually independent, and the power supplies for the IGBT module of the all-solid-state direct current breaker cannot be mutually influenced. The frequency and the voltage of the current are improved through the resonant capacitor assembly and the magnetic ring transformer, and the volume of the high-potential energy supply device is greatly reduced due to the adoption of the high-frequency working frequency. The LCC series-parallel resonant circuit can realize zero-voltage switching or zero-current switching of the IGBT module, reduce switching loss, improve switching frequency, and avoid the technical problems of turn-off overvoltage and bus voltage virtual height caused by a hard switching circuit. The discharge resistor connected with the high-voltage energy storage filter capacitor in parallel can discharge the electric quantity in the capacitor more quickly when the high-potential energy supply device cuts off power supply, and the safety of a circuit and workers is better protected.

Preferably, the magnetic ring transformer is a nanocrystalline or manganese zinc ferrite magnetic ring transformer. The quasi-magnetic ring transformer can inhibit low-frequency interference.

Compared with the prior art, the utility model discloses following beneficial effect has:

the power electronic switch of the rated current path branch of the all-solid-state direct current circuit breaker is composed of the thyristor, the fault current cutting time is shorter, the short-circuit current peak value is smaller, the arc extinguishing energy is greatly reduced, and the thyristor is connected with the direct current voltage-sharing loop and the dynamic direct current voltage-sharing loop in parallel, so that the thyristor is further protected from being damaged.

The design of the full-bridge IGBT module bidirectional through-current branch in the full-solid-state direct-current circuit breaker can enable the upper and lower groups of IGBT modules to bear half of load current respectively, and therefore the short-circuit fault current breaking capacity is doubled. And each full-bridge IGBT module bidirectional through-flow branch is connected in parallel with a direct-current capacitor and an MOV zinc oxide arrester, so that residual electric energy in a circuit can be absorbed and quickly released, the RCD protection absorption branch connected with the two ends of the IGBT module and a resistor with direct-current voltage equalizing and discharging energy can slow down the rising speed of voltage when the IGBT module is turned off, the turn-off loss is reduced, and the IGBT module is further protected from being damaged.

The input power supply of the high-potential functional device is a three-phase alternating-current power supply and is separately supplied with power with the direct-current power supply through which the all-solid-state direct-current circuit breaker passes, so that the isolation is good, the influence of the fault current of the all-solid-state direct-current circuit breaker is avoided, and the stability of the control power supply when the fault current occurs in the solid-state direct-current circuit breaker is ensured. The power supplies after the transformation of each transformer are mutually independent, and the power supplies for the IGBT module of the all-solid-state direct current breaker cannot be mutually influenced.

Due to the adoption of the high-frequency working frequency, the volume of the high-potential energy supply device is greatly reduced.

The high-potential functional device is provided with a discharge resistor connected with the high-voltage energy storage filter capacitor in parallel, and the discharge resistor can discharge the electric quantity in the capacitor more quickly when the high-potential energy supply device cuts off power supply, so that the safety of a circuit and workers is better protected.

Drawings

Fig. 1 is a topological structure diagram of an all-solid-state dc circuit breaker;

FIG. 2 is a view of a thyristor cell topology;

FIG. 3 is a topology structure diagram of an IGBT module, an RCD protection absorption branch circuit and a DC voltage-sharing resistor;

FIG. 4 is a topology structural view of a power electronic switch assembly of embodiment 2;

FIG. 5 is a topological structure diagram of a high-potential energy supply device.

The labels in the figure are: 1. A mechanical isolator; 2. a current limiting inductor; 3; a rated current path branch; 4. a fault current cutting branch circuit; 5. a power electronic switching assembly; 51. a thyristor unit; 52; a direct current voltage-sharing branch; 53. a dynamic voltage-sharing branch; 6. an IGBT assembly; 7. an IGBT unit; 8. an IGBT module; 9. an RCD protection absorption branch; 10. a DC voltage-sharing resistor; 11. a PMW pulse width modulation rectification circuit; 12. a full-bridge inverter circuit; 13. an LCC series-parallel resonant circuit; 14. a full bridge rectifier diode assembly; 15. a resonant capacitive component; 16. a magnetic ring transformer.

Detailed Description

The invention will be further described with reference to the embodiments shown in the drawings to which:

example 1

As shown in fig. 1, 2 and 3, a medium-high voltage bidirectional full-solid-state dc circuit breaker includes a mechanical isolation switch 1, a current-limiting inductor 2, a rated current path branch 3 and a fault current cutting branch 4, where the rated current path branch 3 and the fault current cutting branch 4 are connected in parallel; the mechanical isolating switch 1 is used for isolating a power supply, a circuit without load current is disconnected, arc extinguishing capacity is not available, the current limiting inductor 2 is used for inhibiting transient current, and the inhibiting effect on the current with the higher change rate is more obvious. The inductance value depends on the requirements of stable operation of the system. The rated current path branch 3 comprises a power electronic switch component 5 and an IGBT component 6 which are connected in series, the power electronic switch component 5 is formed by connecting a plurality of groups of thyristor units 51 in series, and each group of thyristor units 51 is formed by connecting a forward thyristor, a direct current voltage-sharing branch 52, a dynamic voltage-sharing branch 53 and a reverse thyristor in parallel; the on-state resistance of the thyristor switch is very small, the voltage resistance is very high at the level of m omega, about 8kV, the turn-off time is short and is about one percent of that of a mechanical switch, the fault current cutting time is shorter, the short-circuit current peak value is smaller, and the arc extinguishing energy is greatly reduced. The IGBT assembly 6 is formed by connecting a plurality of groups of IGBT units 7 in parallel; the fault current cutting branch circuit 4 is formed by connecting a plurality of groups of IGBT units 7 in series; the IGBT unit 7 comprises a full-bridge IGBT module bidirectional through-flow branch and an energy absorption branch, a bridge arm of the IGBT module bidirectional through-flow branch is a crimping type IGBT module 8, the IGBT module 8 is an insulated gate bipolar transistor module, and two ends of the IGBT module 8 are connected with an RCD protection absorption branch 9 and a direct current equalizing resistor 10. The RCD protection absorption branch 9 includes a diode, a resistor, and a dc capacitor, and the resistor is connected in parallel with the diode and then connected in series with the dc capacitor. The rising speed of voltage when IGBT module 8 shuts down can be slowed down, turn-off loss is reduced, the residual energy in the system is discharged more quickly, direct current grading resistor 10 guarantees that the voltage drop born at the two ends of IGBT module 8 of every IGBT unit 7 is basically the same, and the electric energy can be discharged in a helping way. The full-bridge IGBT module bidirectional through-flow branch is connected with an energy absorption branch in parallel, and the energy absorption branch is formed by connecting a direct-current capacitor and an MOV zinc oxide arrester in parallel. When residual electric energy in the circuit charges the direct current capacitor, if the voltage insulation matching level of the two ends of the direct current capacitor is horizontal, the MOV zinc oxide lightning arrester acts to quickly discharge the electric energy, and the IGBT unit 7 is protected from being damaged. And the design of the full-bridge IGBT module bidirectional through-current branch can ensure that the upper and lower groups of IGBT modules 8 respectively bear half of the load current, so that the short-circuit fault breaking current capacity is doubled.

Normally, the rated current path branch 3 carries the entire load current and is always in the on state. Because the on-state voltage drop of the power electronic switch assembly 5 and the IGBT assembly 6 is small, the loss of the direct current circuit breaker is low, and the overall operation efficiency of a power supply system cannot be influenced. Once a main loop is short-circuited or fault current rises, the series IGBT unit 7 of the fault current removal branch 4 is immediately triggered to be conducted, then the parallel IGBT unit 7 of the rated current path branch 3 enters a turn-off state, current starts to transfer to the fault current removal branch 4, the power electronic switch assembly 5 also enters the turn-off state after thyristor current of the power electronic switch assembly 5 is reduced to zero, and the power electronic switch assembly 5 has the capacity of bearing high voltage due to the characteristics of a thyristor. The direct current voltage-sharing branch 52 and the dynamic voltage-sharing branch 53 of the thyristor unit 51 are connected in parallel with the thyristor, so that the rising speed of the voltage at two ends of the thyristor is slowed down, and the loss of devices is reduced. After the fault current is transferred to the fault current cutting branch circuit 4, the series IGBT unit 7 of the fault current cutting branch circuit 4 enters a turn-off state, because the current in the main loop is large, the energy stored on the current limiting inductor 2 is large, the arc energy cannot disappear immediately, and the energy absorption branch circuit of the series IGBT unit 7 of the fault current cutting branch circuit 4 starts to absorb and discharge the energy.

Example 2

As shown in fig. 1, fig. 2, fig. 3, and fig. 4, a medium-high voltage bidirectional full-solid-state dc circuit breaker includes a mechanical isolator 1, a current-limiting inductor 2, a rated current path branch 3, and a fault current cutting branch 4, where the rated current path branch 3 and the fault current cutting branch 4 are connected in parallel; the mechanical isolating switch 1 is used for isolating a power supply, a circuit without load current is disconnected, arc extinguishing capacity is not available, the current limiting inductor 2 is used for inhibiting transient current, and the inhibiting effect on the current with the higher change rate is more obvious. The inductance value depends on the requirements of stable operation of the system. The rated current path branch 3 comprises a power electronic switch component 5 and an IGBT component 6 which are connected in series, the power electronic switch component 5 comprises a plurality of groups of thyristors which are connected in series and two pairs of diodes which are connected on the rated current path branch 3, each group of thyristors are connected in parallel with a direct current voltage-sharing branch 52 and a dynamic voltage-sharing branch 53, each pair of diodes are connected in series in a reverse direction, and the input ends and the output ends of the plurality of groups of thyristors which are connected in series are respectively connected between each pair of diodes of the two pairs of diodes; two pairs of diodes ensure that the current can flow in two directions, and compared with the embodiment 1, the power electronic switch component 5 can reduce half of thyristor devices, thereby saving the cost. The on-state resistance of the thyristor switch is very small, the voltage resistance is very high at the level of m omega, about 8kV, the turn-off time is short and is about one percent of that of a mechanical switch, the fault current cutting time is shorter, the short-circuit current peak value is smaller, and the arc extinguishing energy is greatly reduced. The IGBT assembly 6 is formed by connecting a plurality of groups of IGBT units 7 in parallel; the fault current cutting branch circuit 4 is formed by connecting a plurality of groups of IGBT units 7 in series; the IGBT unit 7 comprises a full-bridge IGBT module bidirectional through-flow branch and an energy absorption branch, a bridge arm of the IGBT module bidirectional through-flow branch is a crimping type IGBT module 8, the IGBT module 8 is an insulated gate bipolar transistor module, and two ends of the IGBT module 8 are connected with an RCD protection absorption branch 9 and a direct current equalizing resistor 10. The RCD protection absorption branch 9 includes a diode, a resistor, and a dc capacitor, and the resistor is connected in parallel with the diode and then connected in series with the dc capacitor. The rising speed of voltage when IGBT module 8 shuts down can be slowed down, turn-off loss is reduced, the residual energy in the system is discharged more quickly, direct current grading resistor 10 guarantees that the voltage drop born at the two ends of IGBT module 8 of every IGBT unit 7 is basically the same, and the electric energy can be discharged in a helping way. The full-bridge IGBT module bidirectional through-flow branch is connected with an energy absorption branch in parallel, and the energy absorption branch is formed by connecting a direct-current capacitor and an MOV zinc oxide arrester in parallel. When residual electric energy in the circuit charges the direct current capacitor, if the voltage insulation matching level of the two ends of the direct current capacitor is horizontal, the MOV zinc oxide lightning arrester acts to quickly discharge the electric energy, and the IGBT unit 7 is protected from being damaged. And the design of the full-bridge IGBT module bidirectional through-current branch can ensure that the upper and lower groups of IGBT modules 8 respectively bear half of the load current, so that the short-circuit fault breaking current capacity is doubled.

Example 3

As shown in fig. 5, a high potential energy supply device includes a PMW pulse width modulation rectification circuit 11, a filter capacitor, a full bridge inverter circuit 12, a resonant capacitor assembly 15, a magnetic loop transformer 16, a full bridge rectifier diode assembly 14, a high voltage energy storage filter capacitor, a bleed-off resistor, and a dc voltage converter; the power supply of the device is three-phase alternating current, and is separately supplied with power with the direct current power supply through which the all-solid-state direct current circuit breaker passes, so that the device is well isolated, cannot be influenced by fault current of the all-solid-state direct current circuit breaker, and ensures the stability of the control power supply when the fault current occurs in the solid-state direct current circuit breaker. The PMW pulse width modulation rectification circuit 11, the filter capacitor and the full-bridge inverter circuit 12 are connected in parallel in sequence; the PMW pulse width modulation rectification circuit 11 comprises a three-phase half-bridge circuit consisting of an inductor at an alternating current side and an IGBT module; the bridge arm of the full-bridge inverter circuit 12 is an IGBT module; the output end of the full-bridge inverter circuit 12 is connected with the input end of the resonant capacitor component 15; the output end of the resonant capacitor assembly 15 is connected with a primary loop of a magnetic loop transformer 16, and leakage inductance of the resonant capacitor assembly 15 and the magnetic loop transformer 16 form an LCC series-parallel resonant circuit 13. The magnetic loop transformer 16 is a nanocrystalline or manganese-zinc ferrite magnetic loop transformer, and the magnetic loop transformer 16 can inhibit low-frequency interference. The power supplies after the transformation of each transformer are mutually independent, and the power supplies for the IGBT module 8 of the all-solid-state direct current breaker cannot be mutually influenced. The LCC series-parallel resonant circuit 13 increases the frequency and voltage of the current, so that the volume of the high-potential energy supply device can be greatly reduced. The LCC series-parallel resonant circuit 13 can realize zero-voltage switching or zero-current switching of the IGBT module, reduce switching loss, improve switching frequency, and avoid technical problems of turn-off overvoltage and bus voltage virtual height caused by a hard switching circuit. The secondary circuit of the magnetic ring transformer 16 is connected with the input end of the full-bridge rectifier diode component 14, the high-voltage energy storage filter capacitor and the bleeder resistor are connected in parallel in sequence, and the bleeder resistor can discharge the electric quantity in the capacitor more quickly when the high-potential energy supply device cuts off the power supply, so that the safety of a better protection circuit and a worker is ensured. The output end of the bleeder resistor is connected with the direct-current voltage converter. The output end of the direct-current voltage converter provides a switch driving power supply required by an IGBT module 8 of the all-solid-state direct-current circuit breaker. The number of the magnetic ring transformer 16, the full-bridge rectifier diode assembly 14, the high-voltage energy storage filter capacitor, the bleeder resistor and the direct-current voltage converter is the same as that of the IGBT modules in the full-solid-state direct-current circuit breaker.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims

1. A middle-high voltage bidirectional full-solid-state direct current circuit breaker comprises a mechanical isolating switch (1), a current-limiting inductor (2), a rated current path branch (3) and a fault current removing branch (4), wherein the rated current path branch (3) and the fault current removing branch (4) are connected in parallel; the power electronic switch assembly is characterized in that the rated current passage branch (3) comprises a power electronic switch assembly (5) and an IGBT assembly (6) which are connected in series, the power electronic switch assembly (5) is formed by connecting a plurality of groups of thyristor units (51) in series, and each group of thyristor units (51) is formed by connecting a forward thyristor, a direct current voltage-sharing branch (52), a dynamic voltage-sharing branch (53) and a reverse thyristor in parallel; the IGBT assembly (6) is formed by connecting a plurality of groups of IGBT units (7) in parallel; the fault current cutting branch circuit (4) is formed by connecting a plurality of groups of IGBT units (7) in series; the IGBT unit (7) comprises a full-bridge IGBT module bidirectional through-flow branch and an energy absorption branch, the full-bridge IGBT module bidirectional through-flow branch is connected with the energy absorption branch in parallel, a bridge arm of the IGBT module bidirectional through-flow branch is an IGBT module (8), and two ends of the IGBT module (8) are connected with an RCD protection absorption branch (9) and a DC voltage-sharing resistor (10).

2. The medium-high voltage bidirectional all-solid-state direct current circuit breaker according to claim 1, characterized in that the IGBT module (8) is a crimped IGBT module.

3. The medium-high voltage bidirectional all-solid-state direct current circuit breaker according to claim 1 or 2, wherein the energy absorption branch is composed of a direct current capacitor and an MOV zinc oxide arrester connected in parallel.

4. The medium-high voltage bidirectional full solid-state direct current circuit breaker according to claim 1 or 2, wherein the RCD protection absorption branch (9) comprises a diode, a resistor and a direct current capacitor, and the resistor of the RCD protection absorption branch (9) is connected in parallel with the diode and then connected in series with the direct current capacitor.