CN112787315B - Pure solid-state short circuit protection device for ship direct-current power grid - Google Patents
Pure solid-state short circuit protection device for ship direct-current power grid Download PDFInfo
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- CN112787315B CN112787315B CN201911088727.9A CN201911088727A CN112787315B CN 112787315 B CN112787315 B CN 112787315B CN 201911088727 A CN201911088727 A CN 201911088727A CN 112787315 B CN112787315 B CN 112787315B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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Abstract
The utility model provides a pure solid-state short-circuit protection device of boats and ships direct current electric wire netting, its includes at least two short-circuit protection modules that the structure is the same, the symmetry sets up, and short-circuit protection module passes through direct current bus connection and is connected with corresponding direct current network deployment electric push device respectively. The short-circuit protection device has the functions of energy allocation, voltage control, current/power limitation and the like among the direct-current buses while having the redundant turn-off protection capability, can realize active control of a direct-current power grid, adopts a back-to-back DC/DC optimization structure, can form a sectional topology, each side of the sectional topology is formed into a cabinet, the cabinet bodies are completely mirror-symmetrical, and the two parts are connected together to form a group of short-circuit protection devices.
Description
Technical Field
The invention relates to the technical field of ship electric propulsion, in particular to a pure solid-state short circuit protection device for a ship direct-current power grid.
Background
The good maneuverability of electric propulsion makes it applied in the field of ship power, and with the development of power electronic technology, the alternating current variable frequency electric propulsion device is widely applied to ships. In recent years, with the development of power electronic technology and the expansion of direct current application concepts, the electric propulsion system of the direct current power grid is beginning to be applied in the market, so as to meet the comprehensive requirements of shipowners and society on water path traffic energy conservation and environmental protection.
Compared with an alternating current power grid electric propulsion system, the direct current networking electric propulsion system has outstanding technical advantages in the aspects of distributed power supply access, energy storage release, load disturbance suppression, energy conservation, emission reduction and noise reduction, and the direct current hybrid power propulsion formed by variable-speed power generation, large-capacity energy storage and variable-frequency driving technology can effectively solve the technical problems of insufficient stability, reliability and economy of the alternating current networking electric propulsion system.
Therefore, the electric propulsion of small and medium-sized ships is developed in the aspect of direct-current networking at present based on the advantages of economical driving and space saving. Fig. 1 shows a topology diagram of an existing ac networking and dc networking electric propulsion system. The difference between the direct current networking and the alternating current networking is that a single diesel engine is directly rectified and merged into a direct current power grid, the direct current networking does not involve the problems of parallel operation of a generator and an alternating current distribution board, and meanwhile, the distribution board and a transformer at the front end are omitted in electric propulsion. The direct-current power grid has no phase requirement, so that the diesel engine set can realize variable-speed power generation according to the current load change so as to improve the efficiency of the whole electric propulsion system and improve the fuel economy of the propulsion system.
Disclosure of Invention
In order to solve the problems, the invention provides a pure solid-state short-circuit protection device for a ship direct-current power grid, which comprises at least two short-circuit protection modules which have the same structure and are symmetrically arranged, wherein the short-circuit protection modules are connected through direct-current buses and are respectively connected with corresponding direct-current networking electric pushing devices.
According to one embodiment of the invention, the short-circuit protection module comprises:
the first direct current capacitor is used for being connected between the positive electrode and the negative electrode of the direct current networking electric pushing device;
a first port of the first switch tube forms a first positive electrode port of the short-circuit protection module and is used for being connected with a positive electrode of the direct-current networking electric pushing device;
a first port of the inductor is connected with a second port of the first switching tube, and the second port forms a second positive electrode port of the short-circuit protection module and is used for being connected with other short-circuit protection modules through a direct-current bus;
a first port of the second switching tube is connected with a second port of the first switching tube, and the second port forms a first negative port and a second negative port of the short-circuit protection module, so as to be connected with a negative electrode of the direct-current networking electric pushing device through the first negative port and connected with other short-circuit protection modules through the second negative port;
and one end of the second direct current capacitor is connected with the second port of the inductor, and the other end of the second direct current capacitor is connected with the second port of the second switching tube.
According to an embodiment of the invention, the short-circuit protection device further comprises:
and a first port of the third switching tube forms a first negative port of the short-circuit protection module so as to be connected with a negative electrode of the direct-current networking electric pushing device, and a second port of the third switching tube is connected with a second port of the second switching tube.
According to an embodiment of the invention, the short-circuit protection device further comprises:
a chopper circuit connected between a first positive terminal port and a first negative terminal port of the short-circuit protection module.
According to an embodiment of the present invention, the chopper circuit includes:
a first port of the fourth switching tube is connected with a first positive electrode port of the short-circuit protection module;
and one end of the chopper resistor is connected with the second port of the fourth switching tube, and the other end of the chopper resistor is connected with the first negative electrode port of the short-circuit protection module.
According to an embodiment of the present invention, the chopper circuit further includes:
and a first port of the fifth switching tube is connected with a second port of the fourth switching tube, and the second port is connected with a first negative electrode port of the short-circuit protection module.
According to an embodiment of the present invention, the chopper circuit further includes:
and the anode of the clamping diode is connected with the first cathode port of the short-circuit protection module, and the cathode of the clamping diode is connected with the second port of the fourth switching tube.
According to one embodiment of the invention, the first direct current capacitor is integrated in the chopper circuit.
According to one embodiment of the invention, when the short-circuit protection device is integrally arranged, different short-circuit protection modules share the second direct-current capacitor.
According to one embodiment of the present invention, each switching tube includes a switching section and a freewheeling diode connected in anti-parallel with the switching section.
The ship direct-current power grid pure solid-state short-circuit protection device provided by the invention has the redundant turn-off protection capability, and simultaneously has the functions of energy allocation, voltage control, current/power limitation and the like among direct-current buses, and can realize active control of a direct-current power grid.
The short-circuit protection device adopts a back-to-back DC/DC optimized structure, so that a sectional topology can be formed, each side of the sectional topology is formed into a cabinet, the cabinet bodies are completely in mirror symmetry, and the two parts are connected together to form a group of short-circuit protection devices. The structure can evenly distribute each group of short-circuit protection devices at two ends of the converter cabinet which needs to be electrically connected, thereby ensuring the symmetry of the cabinet bodies at two sides after the short-circuit protection devices are arranged in the cabinet bodies. Meanwhile, after half protection devices (namely, one short-circuit protection module) are arranged at two ends of each converter cabinet, a plurality of groups of converter cabinets can conveniently form a main stream bus or a direct current ring network, and therefore engineering application adaptability of the device is greatly improved.
And each short-circuit protection switch can be independently controlled, so that chopping and single-side protection module actions in the half cabinet can be independently controlled, real-time cooperativity of turn-off and chopping is ensured, and high-precision time sequence control ensures the reliability of transient overvoltage suppression of turn-off of the solid-state switch.
Meanwhile, the short-circuit protection device adopts a positive and negative electrode redundancy shutoff topological structure, so that the whole device can still normally pass current and can be normally shut off when a certain switching tube fails, and the reliability of the whole device is improved.
In addition, the short-circuit protection device adopts the symmetrical follow current mode of the switching tube to raise the voltage between the switching bridges at the moment of switching off the solid-state circuit breaker, and the voltage is removed from the two sides of the solid-state switch at the moment of switching off the solid-state switch instead of a bypass RLC circuit and an MOV circuit, so that the RLC circuit and the MOV circuit are omitted, the number of devices is reduced, and the cost of the whole device is reduced, and the size of the whole device is reduced.
Meanwhile, a chopping circuit is introduced between the positive and negative electrode ports of the short-circuit protection device, so that the chopping circuit has the function of cooperatively inhibiting the overvoltage outside the switch bridge at the moment of switching off the solid-state switch due to fault besides the function of inhibiting the overvoltage of the direct-current bus. When the controller controls the device to break, chopping is started, and the chopping circuit can form an RL circuit to inhibit high voltage generated at the moment of turn-off, so that the two purposes of one device are realized, overvoltage at the moment of turn-off of the solid-state switch at the moment of short-circuit fault is further reduced, and the comprehensive performance of the protection device is improved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required in the description of the embodiments or the prior art:
FIG. 1 is a schematic topology of an existing AC and DC networked electric propulsion system;
fig. 2 is a schematic structural view of a conventional hybrid circuit breaker;
FIG. 3 is a schematic diagram of a prior art solid state crowbar;
fig. 4 is a schematic structural diagram of a pure solid-state short-circuit protection device for a ship direct-current power grid according to an embodiment of the invention;
fig. 5 is a schematic structural diagram of a pure solid-state short-circuit protection device for a ship direct-current power grid according to an embodiment of the invention;
fig. 6 is a schematic structural diagram of a pure solid-state short-circuit protection device for a ship direct-current power grid according to another embodiment of the invention;
fig. 7 is a schematic structural diagram of a pure solid-state short-circuit protection device for a ship direct-current power grid according to another embodiment of the invention;
fig. 8 is a schematic structural diagram of a pure solid-state short-circuit protection device for a ship direct-current power grid according to still another embodiment of the invention.
Detailed Description
The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details or with other methods described herein.
The ship electric propulsion system adopting the direct-current networking mode reduces large-scale equipment such as an alternating-current distribution board, a transformer and the like, saves a large amount of space and lightens the weight of the whole system. However, since the grid is changed from an ac bus to a dc bus, this also raises technical problems in terms of grid protection.
The traditional alternating current power grid bus-bar switch is provided with a mature circuit breaker as short-circuit breaking protection, and the alternating current circuit breaker realizes breaking of power grid faults by using the alternating current zero crossing point characteristic. The direct-current power grid has no alternating-current characteristics, and the current rises rapidly at the moment of short circuit, so that the breaking of the direct-current power grid during fault has extremely high technical difficulty.
With the rise of the terrestrial direct current power grid in recent years, direct current circuit breakers emerge to be researched and applied with hot tide. The main characteristics of the land DC power grid protection device (DC breaker) are the form of a hybrid breaker, no space limitation, single-stage turn-off, high-voltage low-current turn-off within a few milliseconds.
At present, ship direct current power grid circuit breakers at home and abroad mainly have two types. One type is realized by a converter (DC/DC), and is characterized by realizing active allocation of power grid energy and microsecond-level turn-off, but the power loss is large and the cost is high.
Another class is circuit breakers derived from terrestrial dc network circuit breakers (including hybrid circuit breakers and solid state circuit breakers without mechanical parts, as shown in fig. 2 and 3). The hybrid circuit breaker has the advantages of low normal working loss and the disadvantages of large volume, switching-off time of only millisecond level, complex switching-off control and high cost. The solid-state circuit breaker has advantages in the aspects of size, cost and the like, and is suitable for application conditions of ships with low full-power continuous through-current probability. Because the load and the power supply on the ship direct-current power grid are uniformly distributed on the bus, the pure solid-state circuit breaker does not cause a large amount of energy loss under the normal working condition of the ship, and the pure solid-state circuit breaker (comprising a DC/DC converter type and a common solid-state type) is suitable for the ship direct-current power grid.
The two types of direct current power grid protection devices are used for ships, and have the following main problems: the current transformer (DC/DC) type protection device has no redundant function, large power loss, relatively large occupied volume of the reactor and high cost; the solid-state circuit breaker transient turn-off can excite high voltage pulse at two ends of the circuit breaker, so that the circuit breaker must be provided with energy absorption circuits such as RLC, MOV and the like which respond to ensure that the solid-state switch is not damaged at the turn-off moment, and the overvoltage at the turn-off moment is required to be restrained, so that the solid-state circuit breaker has no advantages in volume, cost and circuit complexity, and does not have the energy allocation, current limiting/power functions of a current transformer (DC/DC) type protection device.
Aiming at the problems in the prior art, the invention provides a novel pure solid-state short-circuit protection device for a ship direct-current power grid. Fig. 4 shows a schematic structural diagram of the pure solid-state short-circuit protection device for the direct-current power grid of the ship in this embodiment.
In consideration of the requirement on the layout of the electric propulsion system in practical application of the ship, the direct-current networking electric propulsion device may be connected by two or more bus bars through a bus-bar switch, and meanwhile, the cabinet body may be placed in a centralized or distributed manner according to the condition of the ship cabin. In order to ensure the symmetry of each section of cabinet body, satisfy different layout mode requirements, and can adapt to the bus arrangement requirements of single line and annular direct current network, the pure solid-state short circuit protection device of ship direct current power grid provided by this embodiment adopts a back-to-back structure.
Specifically, as shown in fig. 4, the pure solid-state short-circuit protection device for a ship dc power grid provided in this embodiment preferably includes at least two short-circuit protection modules (e.g., a first short-circuit protection module 401 and a second short-circuit protection module 402) with the same structure, and the short-circuit protection modules are connected through a dc bus and are respectively connected to corresponding dc networking power pushing devices.
In this embodiment, the dc short-circuit protection device is designed as two symmetrically distributed electrical cabinets, and the two cabinets are respectively arranged at two ends of a bus of the two dc networking electric pushing devices. Two short-circuit protection module cabinet bodies between the direct current network deployment electric pushing device form a set of direct current short-circuit protection device (bus connection switch) through female arranging or cable junction, and the bus connection switch is all arranged at the both ends of every cabinet body, just so can make the cabinet body not only guarantee the symmetry but also be convenient for constitute direct current looped netowrk.
However, if the dc protection devices are arranged in a centralized manner (i.e. one device is arranged in one cabinet), the arrangement of the short-circuit protection devices on one side of the cabinet may cause a great difference between the busbars/connecting wires (stray inductances) on two ends of the short-circuit protection devices, which is inconvenient for the symmetric distribution of the dc propulsion system devices and affects the protection control.
Fig. 5 shows a specific structural schematic diagram of the pure solid-state short-circuit protection device of the ship direct-current power grid in the embodiment. Since the short-circuit protection modules have the same structure, for convenience of description, only one of the short-circuit protection modules is taken as an example for emphasis.
As shown in fig. 5, in this embodiment, the short-circuit protection module 401 includes: the circuit comprises a first switching tube 501, an inductor 502, a second switching tube 503, a second direct current capacitor 504, a third switching tube 505 and a chopper circuit 506. A first port of the first switch tube 501 forms a first positive port of the short-circuit protection device for connecting with a positive electrode of the dc networking power push device, and a second port of the first switch tube is connected with a first port of the inductor 502. The second port of the inductor 502 then forms a second positive port of the short-circuit protection box for connection to other short-circuit protection devices via a dc bus.
Specifically, the switching tube employed in the present embodiment preferably includes a switching section and a freewheeling diode connected in anti-parallel with the switching section. For example, when the switch tube is implemented by an IGBT module, the first port of the first switch tube 501 may be a collector of the IGBT module, and the second port may be an emitter of the IGBT module. Of course, in other embodiments of the present invention, the switch tube may be implemented by other reasonable devices (e.g., IGCT), and the present invention is not limited thereto.
In this embodiment, a first port of the second switch tube 503 is connected to a second port of the first switch tube 501, and the second port forms a second negative port of the short-circuit protection module. The short-circuit protection module can be connected to other short-circuit protection modules via its second negative terminal.
If the first switch tube 501 and the second switch tube 503 are implemented by IGBT modules, the emitter of the IGBT module forming the first switch tube 501 is connected to the collector of the IGBT module forming the second switch tube 503, and the emitter of the IGBT module forming the second switch tube 503 is connected to the second negative terminal of the short-circuit protection module.
In this embodiment, one end of the second dc capacitor 504 is connected to the second port of the inductor 502, and the other end is connected to the second port of the second switch tube 503.
For the existing ship direct-current power grid short-circuit protection device, when a certain switching device on a DC + bus is damaged, the device cannot realize fault disconnection operation. To solve this problem, as shown in fig. 5, in this embodiment, the short-circuit protection module further includes a third switching tube 505. A first port of the third switching tube 505 forms a first negative port of the short-circuit protection module, so as to be connected with a negative electrode of the dc networking power push device through the first negative port, and a second port thereof is connected with a second port of the second switching tube 503.
The third switching tube 505 is preferably capable of being turned off or turned on simultaneously with the first switching tube 501, so that a protection mode with high redundancy, in which positive and negative buses are turned off simultaneously, exists in the ship power grid. Meanwhile, when one of the switch tubes corresponding to the positive and negative buses is closed, the loop can be cut off, so that external power supply is stopped.
Therefore, the ship direct-current power grid protection method is combined with the characteristics of the ship direct-current power grid, and researches show that the ship direct-current power grid is suitable for a protection mode with high redundancy, namely, the positive bus and the negative bus are turned off simultaneously. Therefore, the pure solid-state short-circuit protection device for the ship direct-current power grid provided by the embodiment introduces the third switching tube arranged at the negative electrode of the direct-current bus, and the redundancy of fault shutdown can be enhanced under the condition that energy allocation and current limiting/power control are not influenced.
It should be noted that, in other embodiments of the present invention, when the third switching tube 505 is not configured, the second port of the second switching tube 503 forms the first negative port of the short-circuit protection module at the same time as the second negative port of the short-circuit protection module.
As shown in fig. 5, in this embodiment, the short-circuit protection module preferably further includes a chopper circuit 506. The chopper circuit 506 is connected between the first positive terminal and the first negative terminal of the short-circuit protection module.
Specifically, in the present embodiment, the chopper circuit 506 preferably includes: a fourth switching tube 507, a chopper resistor 508 and a fifth switching tube 509. A first port of the fourth switching tube 507 is connected to a first positive port of the short-circuit protection module, a second port of the fourth switching tube is connected to a first port of the fifth switching tube 509, and a second port of the fifth switching tube 509 is connected to a first negative port of the short-circuit protection module. One end of the chopper resistor 508 is connected to the second port of the fourth switching tube 507, and the other end is connected to the first negative port of the short-circuit protection module.
In this embodiment, as shown in fig. 5, the short-circuit protection module further includes a first dc capacitor 510. One end of the first dc capacitor 501 is connected to the first port of the fourth switching tube 507, and the other end is connected to the second port of the fifth switching tube 509. Thus, the first dc capacitor 501 is equivalently connected between the first positive terminal and the first negative terminal of the short-circuit protection module.
It should be noted that, in other embodiments of the present invention, the fifth switching tube 509 may be replaced by a clamping diode meeting requirements. At this time, the anode of the clamping diode needs to be connected with the first cathode port of the short-circuit protection module, and the cathode needs to be connected with the second port of the fourth switching tube.
Of course, in other embodiments of the present invention, the fifth switching tube 509 may not be disposed in the chopper circuit 506 according to actual needs, and the present invention is not limited to this.
Meanwhile, it should be noted that in other embodiments of the present invention, when the short-circuit protection module does not include a chopper circuit, the short-circuit protection module may still include the first dc capacitor 510, and at this time, the first dc capacitor 501 may be directly connected between the first positive terminal and the first negative terminal of the short-circuit protection module, that is, the circuit structure shown in fig. 6 is correspondingly formed.
In this embodiment, the third switching tube 505 of the negative electrode of the bus is in an on state in a normal operating state, and when a current flows from left to right, the first switching tube 501 on the positive bus is continuously turned on and off, so as to implement voltage reduction and transmit energy to the intermediate capacitor (i.e., the second dc capacitor 504).
When the current flows in the reverse direction, the short-circuit protection module preferably turns on the switching tube between the positive electrode and the negative electrode (i.e. the second switching tube 503) first, and then turns on the switching tube on the positive electrode bus (i.e. the first switching tube 501) at the moment when the switching tube is turned off, so as to push a high voltage to the left capacitor to realize the boosting process.
And when the positive bus switch is turned off, the switching tube between the positive electrode and the negative electrode is continuously turned on so as to circulate.
The structure of the short-circuit protection module on the right side is completely consistent with that of the short-circuit protection module on the left side, and the short-circuit protection modules on the left side and the right side jointly realize buck-boost back-to-back DC/DC energy scheduling control.
In this embodiment, when the control system monitors that a short circuit occurs at one of the two ends of the short-circuit protection device, it may preferably implement the power grid isolation protection of the normal portion by adopting control modes such as current limiting control, reverse energy scheduling control, and direct turn-off of four switching tubes on the positive and negative buses through the identified short-circuit level.
Under the normal working state, the four switch tubes on the positive and negative buses are in a conducting state, and the current can flow in any two directions. When the control system monitors that a short circuit occurs at one side of the two ends of the short-circuit protection device, the control system preferably controls the four switching tubes on the positive and negative buses to be turned off, and simultaneously turns on the chopper circuit to reduce the instantaneous voltage at the two ends of the short-circuit protection device. It should be noted that, in order to optimize the voltage difference between the switching tubes at the moment when the short-circuit protection device is turned off, in this embodiment, when the four valley-opening tubes on the positive and negative dc buses are controlled to be turned off, the chopper circuit is preferably configured to be in an on state, so that chopping is realized through the switching tubes on the chopper circuit, and an RL loop with a smaller resistance value is formed.
In this embodiment, as shown in fig. 5, when a short circuit occurs at one of two ends of the short-circuit protection device, the protective turn-off is characterized in that a pair of switching tubes at one side far from the short-circuit region plays a role in actual turn-off, and two freewheeling diodes in the switching tubes on the positive and negative dc buses at one side near to the short-circuit region, the freewheeling diodes at two ends of the positive and negative dc buses, and the stray inductances on the busbars at two sides of the switching tube at the side form a transient freewheeling circuit, so as to raise the voltage at the rear end of the switch tube at the far end.
In this embodiment, it is considered that different short-circuit protection modules generally have a longer dc bus bar therebetween, and stray inductance thereof may cause instantaneous induced high voltage to be generated outside the switching tube at the moment of switching off under a fault condition. Therefore, in the present embodiment, the short-circuit protection module incorporates the chopper circuit into the DC/DC type protection device with redundancy and is disposed just outside the switching tube, in order to reduce the instantaneous voltage outside the switch at the moment of turning off.
The DC/DC type short-circuit protection device with redundancy and chopping adopts a structure that chopping and circuit breakers are designed in the same cabinet, so that the original chopping function is ensured, and the chopping can be controlled to be started to reduce the overvoltage outside a switching tube through a chopping circuit (equivalent RL circuit) while the fault is disconnected.
It is noted that when the short-circuit protection arrangement is in an integrated arrangement, different short-circuit protection modules preferably share a second dc capacitor. For example, for the circuit shown in fig. 5, when the short-circuit protection device is integrally arranged, the circuit structure will be changed to the structure shown in fig. 7; this is for the circuit shown in fig. 6, and when the short-circuit protection device adopts an integrated arrangement, the circuit structure will be changed to the structure shown in fig. 8.
As can be seen from the above description, the ship direct-current power grid pure solid-state short-circuit protection device provided by the invention has the redundant turn-off protection capability, and simultaneously has the functions of energy allocation between direct-current buses, voltage control, current/power limitation and the like, and can realize active control of a direct-current power grid.
The short-circuit protection device adopts a back-to-back DC/DC optimized structure, so that a sectional topology can be formed, each side of the sectional topology is formed into a cabinet, the cabinet bodies are completely in mirror symmetry, and the two parts are connected together to form a group of short-circuit protection devices. The structure can evenly distribute each group of short-circuit protection devices at two ends of the converter cabinet which needs to be electrically connected, thereby ensuring the symmetry of the cabinet bodies at two sides after the short-circuit protection devices are arranged in the cabinet bodies. Meanwhile, after half protection devices (namely, one short-circuit protection module) are arranged at two ends of each converter cabinet, a plurality of groups of converter cabinets can conveniently form a main stream bus or a direct current ring network, and therefore engineering application adaptability of the device is greatly improved.
And each short-circuit protection switch can be independently controlled, so that chopping and single-side protection module actions in the half cabinet can be independently controlled, real-time cooperativity of turn-off and chopping is ensured, and high-precision time sequence control ensures the reliability of transient overvoltage suppression of turn-off of the solid-state switch.
Meanwhile, the short-circuit protection device adopts a positive and negative electrode redundancy shutoff topological structure, so that the whole device can still normally pass current and can be normally shut off when a certain switching tube fails, and the reliability of the whole device is improved.
In addition, the short-circuit protection device adopts the symmetrical follow current mode of the switching tube to raise the voltage between the switching bridges at the moment of switching off the solid-state circuit breaker, and the voltage is removed from the two sides of the solid-state switch at the moment of switching off the solid-state switch instead of a bypass RLC circuit and an MOV circuit, so that the RLC circuit and the MOV circuit are omitted, the number of devices is reduced, and the cost of the whole device is reduced, and the size of the whole device is reduced.
Meanwhile, a chopping circuit is introduced between the positive and negative electrode ports of the short-circuit protection device, so that the chopping circuit has the function of cooperatively inhibiting the overvoltage outside the switch bridge at the moment of switching off the solid-state switch due to fault besides the function of inhibiting the overvoltage of the direct-current bus. When the controller controls the device to break, chopping is started, and the chopping circuit can form an RL circuit to inhibit high voltage generated at the moment of turn-off, so that the two purposes of one device are realized, overvoltage at the moment of turn-off of the solid-state switch at the moment of short-circuit fault is further reduced, and the comprehensive performance of the protection device is improved.
It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures or process steps disclosed herein, but extend to equivalents thereof as would be understood by those skilled in the relevant art. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
While the above examples are illustrative of the principles of the present invention in one or more applications, it will be apparent to those of ordinary skill in the art that various changes in form, usage and details of implementation can be made without departing from the principles and concepts of the invention. Accordingly, the invention is defined by the appended claims.
Claims (7)
1. The utility model provides a pure solid-state short-circuit protection device of boats and ships direct current electric wire netting, its characterized in that, the device adopts back-to-back structure, includes two at least structure the same, the short-circuit protection module of symmetry setting, the short-circuit protection module passes through direct current bus connection and is connected with the direct current network deployment electricity that corresponds respectively and pushes away the device, wherein, the short-circuit protection module includes:
the first direct current capacitor is used for being connected between the positive electrode and the negative electrode of the direct current networking electric pushing device;
a first port of the first switch tube forms a first positive electrode port of the short-circuit protection module and is used for being connected with a positive electrode of the direct-current networking electric pushing device;
a first port of the inductor is connected with a second port of the first switching tube, and the second port of the inductor forms a second positive electrode port of the short-circuit protection module so as to be connected with other short-circuit protection modules through a direct-current bus;
a first port of the second switching tube is connected with a second port of the first switching tube, and the second port of the second switching tube forms a first negative port and a second negative port of the short-circuit protection module, so that the second switching tube is connected with a negative electrode of the direct-current networking electric pushing device through the first negative port and is connected with other short-circuit protection modules through the second negative port;
one end of the second direct current capacitor is connected with the second port of the inductor, and the other end of the second direct current capacitor is connected with the second port of the second switching tube;
a third switch tube, a first port of which forms a first negative port of the short-circuit protection module for connecting with a negative electrode of the direct-current networking power push device, and a second port of which is connected with a second port of the second switch tube, wherein,
each switching tube comprises a switching part and a freewheeling diode connected with the switching part in inverse parallel.
2. The apparatus of claim 1, wherein the short circuit protection device further comprises:
a chopper circuit connected between a first positive terminal port and a first negative terminal port of the short-circuit protection module.
3. The apparatus of claim 2, the chopper circuit comprising:
a first port of the fourth switching tube is connected with a first positive electrode port of the short-circuit protection module;
and one end of the chopper resistor is connected with the second port of the fourth switching tube, and the other end of the chopper resistor is connected with the first negative electrode port of the short-circuit protection module.
4. The apparatus of claim 3, the chopper circuit further comprising:
and a first port of the fifth switching tube is connected with a second port of the fourth switching tube, and a second port of the fifth switching tube is connected with a first negative electrode port of the short-circuit protection module.
5. The apparatus of claim 3, the chopper circuit further comprising:
and the anode of the clamping diode is connected with the first cathode port of the short-circuit protection module, and the cathode of the clamping diode is connected with the second port of the fourth switching tube.
6. The apparatus of any of claims 2-5, wherein the first direct current capacitor is integrated in the chopper circuit.
7. The device as claimed in any one of claims 2 to 5, wherein different short-circuit protection modules share the second DC capacitor when the short-circuit protection device is integrally arranged.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911088727.9A CN112787315B (en) | 2019-11-08 | 2019-11-08 | Pure solid-state short circuit protection device for ship direct-current power grid |
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| CN201911088727.9A CN112787315B (en) | 2019-11-08 | 2019-11-08 | Pure solid-state short circuit protection device for ship direct-current power grid |
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| CN112787315B true CN112787315B (en) | 2022-03-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9502884B2 (en) * | 2013-08-15 | 2016-11-22 | University Of South Carolina | Methods and systems for protecting DC circuits |
| CN103928912B (en) * | 2014-05-08 | 2016-07-13 | 武汉大学 | A kind of short-circuit protection method of the solid state switch of direct-current micro-grid |
| US9853451B2 (en) * | 2015-01-30 | 2017-12-26 | General Electric Company | Direct current power system |
| KR102467807B1 (en) * | 2017-01-13 | 2022-11-15 | 지멘스 에너지 에이에스 | DC power switching assembly and method |
| CN108964524A (en) * | 2017-05-26 | 2018-12-07 | 西安中车永电捷通电气有限公司 | Permanent magnet synchronous motor trailer system |
| CN109936352A (en) * | 2017-12-19 | 2019-06-25 | 株洲中车时代电气股份有限公司 | All solid state dc circuit breaker and its control method based on IGBT |
| CN108599117B (en) * | 2018-05-11 | 2019-08-09 | 西北工业大学 | A kind of bidirectional, dc solid circuit breaker |
| CN109617028B (en) * | 2018-12-20 | 2020-04-24 | 武汉船用电力推进装置研究所（中国船舶重工集团公司第七一二研究所） | Marine intelligent direct-current bus coupler assembly and control method thereof |
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