CN217469460U - Low-power sag compensation device - Google Patents
Low-power sag compensation device Download PDFInfo
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- CN217469460U CN217469460U CN202220290965.9U CN202220290965U CN217469460U CN 217469460 U CN217469460 U CN 217469460U CN 202220290965 U CN202220290965 U CN 202220290965U CN 217469460 U CN217469460 U CN 217469460U
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Abstract
The utility model discloses a small-power sag compensation device, which comprises a wire inlet switch unit, a wire outlet switch unit, a bypass maintenance unit, an electronic bypass unit, an AC/DC inversion unit, a DC conversion unit and a DC energy storage unit; the bypass maintenance unit is positioned between the incoming line power supply and the sensitive load; the incoming line switch unit, the electronic bypass unit and the outgoing line switch unit are sequentially connected in series from an incoming line power supply end to a sensitive load end and are connected in parallel with the bypass maintenance unit; an alternating current-direct current inversion unit is connected in parallel between the electronic bypass unit and the outgoing line switch unit; and a direct current conversion unit is connected in series between the alternating current-direct current inversion unit and the direct current energy storage unit. The compensation of the voltage temporary rising, temporary falling or short-time interruption of the incoming line can be realized, and the system efficiency can be improved by adopting a two-stage power change mode.
Description
Technical Field
The utility model relates to an energy storage dc-to-ac converter field especially relates to a low-power compensation arrangement that temporarily falls.
Background
The common AC voltage sag control equipment in the market mainly adopts a single-stage AC/DC converter to realize energy conversion, and the converter technology is mature and widely applied to high-power occasions. However, in a low-power situation, the loss of the single-stage AC/DC converter system is high. The current common direct current converter structure comprises a Buck/Boost bidirectional converter, a double-active full-bridge bidirectional DC-DC converter and the like. The Buck/Boost bidirectional converter is small in input and output conversion range and limited in application.
Due to the existence of the isolation transformer, the double-active full-bridge bidirectional DC-DC converter has wider application in occasions with higher input and output voltages. Based on a double-active full-bridge bidirectional DC-DC converter controlled by a traditional phase-shift control mode, a single PWM plus phase-shift control mode or a double PWM plus phase-shift control mode, each converter has respective advantages and disadvantages, but in a low-power occasion, the efficiency of a sag compensation system is low.
SUMMERY OF THE UTILITY MODEL
The utility model provides a miniwatt compensation arrangement that temporarily falls to it is higher to solve the compensation system consume of temporarily falling under the miniwatt occasion, the problem of system efficiency on the low side.
In order to achieve the above purpose, the present invention adopts the following technical solution.
A low-power sag compensation device comprises an incoming line switch unit, an outgoing line switch unit, a bypass maintenance unit, an electronic bypass unit, an alternating current-direct current inversion unit, a direct current conversion unit and a direct current energy storage unit;
the bypass maintenance unit is positioned between the incoming line power supply and the sensitive load; the incoming line switch unit, the electronic bypass unit and the outgoing line switch unit are sequentially connected in series from an incoming line power supply end to a sensitive load end and are connected in parallel with the bypass maintenance unit;
the alternating current-direct current inversion unit is connected in parallel between the electronic bypass unit and the outgoing line switch unit; and the direct current conversion unit is connected in series between the alternating current-direct current inversion unit and the direct current energy storage unit.
Furthermore, the incoming line switch unit, the outgoing line switch unit and the bypass maintenance unit are circuit breakers or load switches, and the live maintenance or fault detection of equipment faults can be realized through the arrangement of the incoming line switch unit, the outgoing line switch unit and the bypass maintenance unit.
Furthermore, the alternating current-direct current inversion unit is a three-phase full-bridge inverter capable of realizing bidirectional energy flow. The topological structure of the alternating current-direct current inversion unit is one of a two-level bridge, a three-level bridge and an H bridge. When the system is subjected to sag, the electronic bypass unit is disconnected, and the alternating current-direct current inversion unit converts direct current electric energy transmitted by the direct current conversion unit into three-phase alternating current which is in the same phase as and has the same amplitude as the sensitive load power supply, so that the voltage stability of the sensitive load is ensured; meanwhile, when the direct current energy storage unit is charged, the alternating current-direct current inversion unit takes electricity from the incoming line power supply, rectifies the electricity into direct current and sends the direct current into the direct current conversion unit.
Further, the direct current conversion unit is a dual-active full-bridge bidirectional DC-DC converter based on a TCM hybrid frequency conversion control mode. The double-active full-bridge bidirectional DC-DC converter based on the TCM hybrid frequency conversion control mode has symmetrical structure, can realize the electrical isolation of a direct current low-voltage side and a direct current high-voltage side, can also realize that all switching tubes work in a soft switching mode, the leakage inductance of a transformer can be absorbed by an inductor, and the problem of voltage current spike is avoided; phase shift control and triangular wave control are combined based on a TCM hybrid frequency conversion control mode, so that the total loss of the converter can be reduced in a full-load range by the direct current conversion unit, the working efficiency of the converter is improved, and the efficiency of the low-power sag compensation device is improved.
Further, the direct current energy storage unit comprises an energy storage module and a charge and discharge control module connected with the energy storage module. The energy storage module is one of a super capacitor, a super capacitor bank, a storage battery pack and a flywheel.
In the initial stage of system electrification, the power grid sequentially passes through the alternating current-direct current inversion unit and the direct current conversion unit to charge the direct current energy storage unit for the first time, and is in a floating charging state in the later stage. When the system sends short-time voltage drop or temporary rise or interruption, the direct current energy storage unit supplies power to the sensitive load through the direct current conversion unit and the alternating current-direct current inversion unit; when the system voltage recovers to be normal again, the incoming line power supply charges the energy storage unit through the converter again, and the full power state of the incoming line power supply is guaranteed.
When the incoming line power supply is temporarily dropped, temporarily raised or temporarily interrupted, the system cuts off the fault power supply by disconnecting the electronic bypass unit, and simultaneously, the direct current energy storage unit supplies power to the load through the direct current conversion unit and the alternating current-direct current inversion unit; and after the system is recovered to be normal, the incoming line power supply charges the direct current energy storage unit through the alternating current-direct current inversion unit and the direct current conversion unit. In the low-power sag compensation device, the direct-current conversion unit adopts a double-active full-bridge bidirectional DC-DC converter based on a TCM hybrid frequency conversion control mode, so that the operation efficiency of the whole system is improved, the application of the voltage sag compensation device in a low-power grade is expanded, the efficiency of the low-power voltage sag compensation device is improved possibly, and the high efficiency of the system can be realized in a full-load range. The large-scale popularization of the low-power sag compensation device becomes possible, the reduction of investment cost is finally realized, and the economic benefit is good.
The utility model provides a low-power compensation arrangement that temporarily falls has following advantage:
(1) the utility model provides a power grid voltage sag compensation device of a two-stage converter, which can solve the influence of power grid voltage sag, sag or short-time drop on load voltage;
(2) the utility model discloses a through carrying out real-time supervision to the electric wire netting voltage, when voltage takes place to fall temporarily/rises temporarily or fall for a short time, the system cuts off trouble power supply and sensitive load through cutting off electron bypass unit, and the energy of direct current energy storage unit converts the energy of energy storage into the alternating current through the interchange direct current simultaneously, for sensitive load power supply, has realized the voltage control from 0 to 130% wide range;
(3) the AC-DC conversion part of the utility model is composed of two-stage structures, namely an AC-DC inversion unit and a DC conversion unit;
(4) the utility model discloses a direct current conversion unit adopts two active full-bridge two-way DC-DC converter based on TCM mixes the frequency conversion control mode, reduces converter leading loss through selecting different switching frequency according to different load conditions, optimizes the converter total loss to realize the high efficiency of converter in the full load scope, let the low-power more extensive application of voltage sag compensation arrangement become possible;
(5) the utility model provides a low-power compensation arrangement that temporarily falls for traditional compensation arrangement that temporarily falls, greatly reduced the system loss, promoted system efficiency, be favorable to improving the system volume.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a small power sag compensation device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments.
As shown in fig. 1, an embodiment of the present invention provides a low-power sag compensation device, which includes an incoming line switch unit 1, an outgoing line switch unit 3, a bypass maintenance unit 4, an electronic bypass unit 2, an ac/dc inverter unit 5, a dc conversion unit 6, and a dc energy storage unit 7;
the bypass maintenance unit 4 is positioned between an incoming line power supply and a sensitive load; the incoming line switch unit 1, the electronic bypass unit 2 and the outgoing line switch unit 3 are sequentially connected in series from an incoming line power supply end to a sensitive load end and are connected in parallel with the bypass maintenance unit 4;
the alternating current-direct current inversion unit 5 is connected in parallel between the electronic bypass unit 2 and the outgoing line switch unit 3; the direct current conversion unit 6 is connected in series between the alternating current-direct current inversion unit 5 and the direct current energy storage unit 7.
When the incoming line power supply is temporarily dropped, temporarily raised or interrupted for a short time, the system cuts off a fault power supply by disconnecting the electronic bypass unit 2, and simultaneously, the direct current energy storage unit 7 supplies power to a sensitive load through the direct current conversion unit 6 and the alternating current-direct current inversion unit 5; after the system is recovered to be normal, the incoming line power supply charges the direct current energy storage unit 7 through the alternating current-direct current inversion unit 5 and the direct current conversion unit 6.
The incoming line switch unit 1, the outgoing line switch unit 3 and the bypass maintenance unit 4 are circuit breakers or load switches, and the live maintenance or fault detection of equipment faults can be realized through the arrangement of the incoming line switch unit 1, the outgoing line switch unit 3 and the bypass maintenance unit 4.
The electronic bypass unit 2 is connected in series between the incoming line power supply and the sensitive load, and is in a closed state when the system works normally, and the sensitive load is powered by the incoming line power supply; when the system is in a sag state, the electronic bypass unit 2 is disconnected, a fault power supply is cut off, and the sensitive load is powered by the direct-current energy storage unit.
In this embodiment, the ac/dc inverter unit 5 is a three-phase full-bridge inverter capable of realizing bidirectional energy flow, and the topology structure thereof can select a two-level, three-level or H-bridge, so as to realize bidirectional energy flow. The alternating current-direct current inversion unit 5 is connected in parallel between the electronic bypass unit 2 and the outgoing line switch unit 3, when the system is in sag, the electronic bypass unit 2 is disconnected, the alternating current-direct current inversion unit 5 converts direct current electric energy transmitted by the direct current conversion unit 6 into three-phase alternating current which is in the same phase as the sensitive load power supply and has the same amplitude value as the sensitive load power supply, and therefore the voltage stability of the sensitive load is guaranteed; meanwhile, when the direct current energy storage unit 7 is charged, the alternating current/direct current inversion unit 5 takes electricity from the incoming line power supply, rectifies the electricity into direct current, and sends the direct current into the direct current conversion unit 6.
In this embodiment, the DC conversion unit 6 is a dual-active full-bridge bidirectional DC-DC converter based on a TCM hybrid frequency conversion control method. The direct current low-voltage side and the direct current high-voltage side can be electrically isolated, and bidirectional flow of energy between the direct current energy storage unit and the direct current inversion unit can also be realized.
The double-active full-bridge bidirectional DC-DC converter based on the TCM hybrid frequency conversion control mode is symmetrical in structure, all switch tubes can work in a soft switch mode, leakage inductance of the transformer can be absorbed by the inductor, and the problem of voltage current spike is solved; based on TCM hybrid frequency conversion control mode, the phase shift control and the triangular wave control are combined, so that the total loss of the converter can be reduced in the full load range by the direct current conversion unit, the working efficiency of the converter is improved, and the efficiency of the low-power sag compensation device is improved. In specific implementation, in order to reduce the calculation amount of the system controller, according to different load conditions, the dominant loss of the dual-active full-bridge bidirectional DC-DC converter can be better optimized by adopting the step-type switching frequency.
In this embodiment, the dc energy storage unit 7 includes an energy storage module and a charge and discharge control module connected thereto. The energy storage module is one of a super capacitor, a super capacitor bank, a storage battery pack and a flywheel. In the initial stage of system electrification, the power grid sequentially passes through the alternating current-direct current inversion unit 5 and the direct current conversion unit 6 to charge the direct current energy storage unit 7 for the first time, and is in a floating charging state in the later stage. When the system sends short-time voltage drop or temporary rise or interruption, the direct current energy storage unit 7 supplies power to the sensitive load through the direct current conversion unit 6 and the alternating current-direct current inversion unit 5; and when the system voltage recovers to be normal again, the incoming line power supply charges the direct current energy storage unit through the converter again to ensure that the direct current energy storage unit is in a full power state.
When the incoming line power supply is temporarily dropped, temporarily raised or temporarily interrupted, the system cuts off a fault power supply by disconnecting the electronic bypass unit 2, and meanwhile, the direct current energy storage unit 7 supplies power to a sensitive load through the direct current conversion unit 6 and the alternating current-direct current inversion unit 5; after the system is recovered to be normal, the incoming line power supply charges the direct current energy storage unit 7 through the alternating current-direct current inversion unit 5 and the direct current conversion unit 6. In the low-power sag compensation device, the direct current conversion unit 6 adopts a double-active full-bridge bidirectional DC-DC converter based on a TCM hybrid frequency conversion control mode, so that the operation efficiency of the whole system is improved, the application of the voltage sag compensation device in a low-power grade is expanded, the efficiency of the low-power voltage sag compensation device is improved possibly, and the high efficiency of the system can be realized in a full-load range.
The foregoing is a more detailed description of the present invention, taken in conjunction with the accompanying preferred embodiments, and it is not intended that the invention be limited to these details, as it is, in particular, the method of placing the device in series with the high side of a distribution transformer and the method will be substantially identical. To the ordinary skilled person in the technical field of the present invention, without departing from the present invention, make a plurality of equivalent substitutes or obvious variants, and the performance or the usage is the same, should all regard as belonging to the protection scope of the present invention.
Claims (7)
1. A low-power sag compensation device is characterized by comprising an incoming line switch unit, an outgoing line switch unit, a bypass maintenance unit, an electronic bypass unit, an alternating current-direct current inversion unit, a direct current conversion unit and a direct current energy storage unit;
the bypass maintenance unit is positioned between the incoming line power supply and the sensitive load; the incoming line switch unit, the electronic bypass unit and the outgoing line switch unit are sequentially connected in series from an incoming line power supply end to a sensitive load end and are connected in parallel with the bypass maintenance unit;
the alternating current-direct current inversion unit is connected in parallel between the electronic bypass unit and the outgoing line switch unit; the direct current conversion unit is connected in series between the alternating current-direct current inversion unit and the direct current energy storage unit.
2. The small power sag compensation device according to claim 1, wherein the incoming switch unit, the outgoing switch unit, and the bypass maintenance unit are circuit breakers or load switches.
3. The low-power sag compensation device according to claim 1, wherein the ac-dc inverter unit is a three-phase full-bridge inverter capable of realizing bidirectional energy flow.
4. The small-power sag compensation device according to claim 3, wherein the AC-DC inverter unit topology is one of a two-level, a three-level, and an H-bridge.
5. The small-power sag compensation device according to any one of claims 1 to 4, wherein the direct-current conversion unit is a dual-active full-bridge bidirectional DC-DC converter based on a TCM hybrid frequency conversion control mode.
6. The small-power sag compensation device according to claim 1, wherein the dc energy storage unit comprises an energy storage module and a charge-discharge control module connected thereto.
7. The small power sag compensation device according to claim 6, wherein the energy storage module is one of a super capacitor, a super capacitor bank, a battery pack, and a flywheel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220290965.9U CN217469460U (en) | 2022-02-11 | 2022-02-11 | Low-power sag compensation device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220290965.9U CN217469460U (en) | 2022-02-11 | 2022-02-11 | Low-power sag compensation device |
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| Publication Number | Publication Date |
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| CN217469460U true CN217469460U (en) | 2022-09-20 |
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| CN202220290965.9U Active CN217469460U (en) | 2022-02-11 | 2022-02-11 | Low-power sag compensation device |
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