CN210839322U - Modular multilevel converter bypass mechanism - Google Patents
Modular multilevel converter bypass mechanism Download PDFInfo
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- CN210839322U CN210839322U CN201921548640.0U CN201921548640U CN210839322U CN 210839322 U CN210839322 U CN 210839322U CN 201921548640 U CN201921548640 U CN 201921548640U CN 210839322 U CN210839322 U CN 210839322U
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Abstract
The utility model provides a many level of modularization transverter bypass mechanism, include: an alternating current breaker QF and six inverter assemblies; the capability of the diode at the lower part of each submodule to bear the impact current is improved, the whole converter is favorable for changing the mode that each submodule is connected with the thyristor in parallel in the traditional scheme into the mode that the thyristors are connected with both ends of all submodules in each bridge arm in parallel, the high-power and high-voltage thyristors can be preferentially selected, the using amount of the thyristors is reduced, the economy is higher, the control is simpler, and the design of the whole structure is also favorable; and the impact current passing through the lower diodes of each submodule can be greatly reduced in an inversion mode, and the reliability is higher.
Description
Technical Field
The utility model relates to a level transverter technical field especially relates to a many level of modularization transverter bypass mechanism.
Background
With the continuous progress of the power semiconductor technology, the flexible direct current transmission (VSC-HVDC) technology based on the voltage source converter becomes a novel power transmission system developed recently, the flexible direct current transmission (VSC-HVDC) technology directly inverts the direct current voltage into the alternating current voltage with controllable amplitude and phase by adopting the Pulse Width Modulation (PWM) technology, the phase change is not required by the voltage of the receiving-end power grid, the system capacity of the receiving-end power grid is not limited, and the flexible direct current transmission system can be used for the connection between an isolated small system and a main grid. The modular multilevel converter MMC is widely applied to VSC-HVDC, and a basic unit of the modular multilevel converter MMC is a half-bridge or full-bridge converter unit; the structure of the converter is similar to that of a chain converter, and a plurality of groups of converter units are cascaded together to form a converter bridge arm; and 6 groups of cascade current converting bridge arms are combined together to form the three-phase current transformer.
When the converter has a direct-current short-circuit fault, if the converter works in a rectification mode, bypass thyristors which are connected with each submodule in parallel need to be conducted, so that a bypass of each bridge arm of the converter is realized, for a high-voltage converter valve, the number of submodules is large, the structure is complex, the cost is high, and the control difficulty is increased; if the converter works in an inversion mode, fault current can form a loop through a diode at the lower part of each submodule, and large impact current can cause damage to the diode, so that the stability of the system is not facilitated.
SUMMERY OF THE UTILITY MODEL
In order to overcome not enough among the above-mentioned prior art, the utility model provides an improved the ability that every submodule piece lower part diode tolerates rush current, be favorable to the many level of transverter bypass mechanism of the configuration optimization's of whole transverter, include: an alternating current breaker QF and six inverter assemblies; the six converter assemblies are divided into three groups, and each group is provided with two converter assemblies;
a first phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies to form a loop;
the second phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies to form a loop;
and the third-phase power output end of the alternating current breaker QF is respectively connected with the two current converter assemblies to form a loop.
It is further noted that the inverter assembly includes: the bridge arm comprises a bypass unit, a converter submodule, a bridge arm resistor and a bridge arm inductor;
the bypass unit is connected with the converter submodule in parallel, and a parallel circuit of the bypass unit and the converter submodule is connected with the bridge arm resistor and the bridge arm inductor in series.
It should be further noted that the converter submodule is provided with a plurality of converter units, and the plurality of converter units are connected in series.
It should be further noted that one end of the parallel circuit of the bypass unit and the converter submodule is connected with the loop;
the other end of the parallel circuit of the bypass unit and the converter submodule is connected with the first end of the bridge arm resistor;
the second end of the bridge arm resistor is connected with the first end of the bridge arm inductor;
and the second end of the bridge arm inductor is connected with the phase electricity output end of the alternating current breaker QF.
It should be further noted that the bypass unit is provided with a first bypass thyristor and a second bypass thyristor;
the first bypass thyristor and the second bypass thyristor are connected in parallel, and the conduction directions of the first bypass thyristor and the second bypass thyristor are opposite.
According to the technical scheme, the utility model has the advantages of it is following:
the mode that each submodule is connected with the thyristor in parallel in the traditional scheme is changed into the mode that the thyristors are connected with two ends of all submodules in parallel in each bridge arm, the high-power and high-voltage thyristors can be preferentially selected, the using amount of the thyristors is reduced, the economy is higher, the control is simpler, and the design of the whole structure is facilitated; and the impact current passing through the lower diodes of each submodule can be greatly reduced in an inversion mode, and the reliability is higher.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of a modular multilevel converter with the bypass architecture;
fig. 2 is a schematic diagram of a discharge circuit when the inverter operates in the inverter mode.
The reference numerals in the figures have the meaning: the circuit comprises a bypass unit 1, a first bypass thyristor 1-1, a second bypass thyristor 1-2, a converter submodule 2, a converter unit 3, a bridge arm resistor 4, a bridge arm inductor 5, a converter assembly 6, a circuit I8, a circuit II 9 and an alternating current breaker QF, wherein the bypass unit 1, the bridge arm resistor 1-1, the bridge arm inductor 5, the converter assembly 6, the circuit I8, the circuit II 9 and the alternating current breaker QF are arranged in sequence.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the following embodiments and drawings are applied to clearly and completely describe the technical solution protected by the present invention, and obviously, the embodiments described below are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of protection of this patent.
The utility model provides a many level of modularization transverter bypass mechanism, as shown in figure 1 and figure 2, include: an ac circuit breaker QF and six inverter assemblies 6; the six converter assemblies 6 are divided into three groups, and each group is provided with two converter assemblies 6;
the first phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies 6 to form a loop; the second phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies 6 to form a loop; and the third-phase power output end of the alternating current breaker QF is respectively connected with the two current converter assemblies 6 to form a loop.
The converter assembly 6 comprises: the bridge-arm current converter comprises a bypass unit 1, a converter submodule 2, a bridge arm resistor 4 and a bridge arm inductor 5; the bypass unit 1 is connected with the converter submodule 2 in parallel, and a parallel circuit of the bypass unit 1 and the converter submodule 2 is connected with the bridge arm resistor 4 and the bridge arm inductor 5 in series.
The utility model relates to a change of current submodule piece 2 is equipped with a plurality of change of current units 3, a plurality of change of current unit 3 series connection.
One end of a parallel circuit of the bypass unit 1 and the converter submodule 2 is connected with a loop; the other end of the parallel circuit of the bypass unit 1 and the converter submodule 2 is connected with the first end of the bridge arm resistor 4; the second end of the bridge arm resistor 4 is connected with the first end of the bridge arm inductor 5; and the second end of the bridge arm inductor 5 is connected with the phase electricity output end of the alternating current breaker QF.
The bypass unit 1 is provided with a first bypass thyristor 1-1 and a second bypass thyristor 1-2; the first bypass thyristor 1-1 and the second bypass thyristor 1-2 are connected in parallel, and the conduction directions of the first bypass thyristor 1-1 and the second bypass thyristor 1-2 are opposite.
The utility model discloses the technical scheme who takes is realized at the parallelly connected bypass structure in the both ends of every submodule piece of many level of modularization transverter, and bypass structure is parallelly connected with each bridge arm submodule piece both ends of many level transverter earlier promptly, establishes ties with bridge arm inductance and bridge arm inductance again.
Moreover, the mode that each submodule is connected with the thyristor in parallel in the traditional scheme is changed into the mode that the thyristors are connected with two ends of all submodules in parallel in each bridge arm, the high-power and high-voltage thyristors can be preferentially selected, the using amount of the thyristors is reduced, the economy is higher, the control is simpler, and meanwhile, the design of the whole structure is facilitated.
The utility model provides a many level transverter bypass structure when taking place direct current short-circuit fault, can realize the reliable bypass of whole converter valve, and simple structure, economic nature are high, have improved the ability that every submodule piece lower part diode endured impulse current, are favorable to the configuration optimization of whole transverter.
The working method of the utility model comprises the following steps:
when the mechanism normally operates, the bypass unit does not act; when a short-circuit fault occurs on the direct current side, the commutation unit of the commutation submodule is locked, and meanwhile, one bypass thyristor in the bypass unit is conducted.
When the mechanism works in a rectification mode, the converter submodule is locked and simultaneously triggers the second bypass thyristor to be conducted, and the second bypass thyristor of the bypass unit is conducted with the bridge arm resistor 4 and the bridge arm inductor 5.
When the mechanism works in an inversion mode, the converter submodule is locked, meanwhile, a first bypass thyristor in the bypass unit is conducted, and a fault current and the converter submodule form a second loop 9 through a bridge arm resistor, a bridge arm inductor and the converter submodule; namely, the fault current forms a second loop 9 through the bridge arm resistor, the bridge arm inductor and the diode of the converter submodule.
And a first loop 8 is formed by the first bypass thyristor, the first bypass thyristor and the converter submodule form shunt, namely the first bypass thyristor and diodes at the lower part of each submodule form shunt, and the impact of short-circuit current on the diodes is reduced.
After the first bypass thyristor forms a loop, the alternating current breaker QF trips, reclosing is carried out after the current on the direct current side attenuates, the converter submodule is unlocked after the reclosing is successful, and the mechanism is restarted.
The mode that each converter submodule is connected with the thyristor in parallel in the traditional scheme is changed into the mode that the thyristors are connected with two ends of all converter submodules in parallel in each bridge arm, the high-power and high-voltage thyristors can be preferentially selected, the using amount of the thyristors is reduced, the economy is higher, the control is simpler, and the design of the whole structure is facilitated; and the impact current passing through the lower diodes of each submodule can be greatly reduced in an inversion mode, and the reliability is higher.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. A modular multilevel converter bypass mechanism, comprising: an alternating current breaker QF and six inverter assemblies (6); the six converter assemblies (6) are divided into three groups, and each group is provided with two converter assemblies (6);
the first phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies (6) to form a loop;
the second phase electric output end of the alternating current breaker QF is respectively connected with the two current converter assemblies (6) to form a loop;
and the third-phase power output end of the alternating current breaker QF is respectively connected with the two current converter assemblies (6) to form a loop.
2. The modular multilevel converter bypass mechanism of claim 1,
the converter assembly (6) comprises: the bridge-arm current conversion device comprises a bypass unit (1), a current conversion submodule (2), a bridge arm resistor (4) and a bridge arm inductor (5);
the bypass unit (1) is connected with the converter submodule (2) in parallel, and a parallel circuit of the bypass unit (1) and the converter submodule (2) is connected with the bridge arm resistor (4) and the bridge arm inductor (5) in series.
3. The modular multilevel converter bypass mechanism of claim 2,
the converter submodule (2) is provided with a plurality of converter units (3), and the converter units (3) are connected in series.
4. The modular multilevel converter bypass mechanism of claim 2,
one end of a parallel circuit of the bypass unit (1) and the converter submodule (2) is connected with a loop;
the other end of the parallel circuit of the bypass unit (1) and the converter submodule (2) is connected with the first end of the bridge arm resistor (4);
the second end of the bridge arm resistor (4) is connected with the first end of the bridge arm inductor (5);
and the second end of the bridge arm inductor (5) is connected with the phase electricity output end of the alternating current breaker QF.
5. The modular multilevel converter bypass mechanism of claim 2,
the bypass unit (1) is provided with a first bypass thyristor (1-1) and a second bypass thyristor (1-2);
the first bypass thyristor (1-1) and the second bypass thyristor (1-2) are connected in parallel, and the conduction directions of the first bypass thyristor (1-1) and the second bypass thyristor (1-2) are opposite.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921548640.0U CN210839322U (en) | 2019-09-16 | 2019-09-16 | Modular multilevel converter bypass mechanism |
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| CN201921548640.0U CN210839322U (en) | 2019-09-16 | 2019-09-16 | Modular multilevel converter bypass mechanism |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110611421A (en) * | 2019-09-16 | 2019-12-24 | 山东泰开高压开关有限公司 | Modular multilevel converter bypass mechanism and working method |
| CN113270941A (en) * | 2021-05-28 | 2021-08-17 | 广东电网有限责任公司 | Low-voltage alternating current-direct current power distribution mode conversion system and time sequence control method and device thereof |
-
2019
- 2019-09-16 CN CN201921548640.0U patent/CN210839322U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110611421A (en) * | 2019-09-16 | 2019-12-24 | 山东泰开高压开关有限公司 | Modular multilevel converter bypass mechanism and working method |
| CN113270941A (en) * | 2021-05-28 | 2021-08-17 | 广东电网有限责任公司 | Low-voltage alternating current-direct current power distribution mode conversion system and time sequence control method and device thereof |
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