CN113488967B - Inverter, direct current conversion unit and shutdown method thereof - Google Patents
Inverter, direct current conversion unit and shutdown method thereof Download PDFInfo
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- CN113488967B CN113488967B CN202110974982.4A CN202110974982A CN113488967B CN 113488967 B CN113488967 B CN 113488967B CN 202110974982 A CN202110974982 A CN 202110974982A CN 113488967 B CN113488967 B CN 113488967B
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- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000001514 detection method Methods 0.000 claims description 14
- 238000005070 sampling Methods 0.000 claims description 10
- 238000004146 energy storage Methods 0.000 claims description 3
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- 230000004048 modification Effects 0.000 description 4
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- 238000001914 filtration Methods 0.000 description 2
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Classifications
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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
- H02H7/10—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 for converters; for rectifiers
- H02H7/12—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 for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—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 for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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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
- H02M3/156—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 with automatic control of output voltage or current, e.g. switching regulators
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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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
Abstract
The application provides an inverter, a direct current conversion unit and a shutdown method thereof. In the shutdown method of the direct current conversion unit, whether the direct current conversion unit needs to be shutdown or not is judged through characteristic harmonic components in the direct current conversion unit, and when the direct current conversion unit needs to be shutdown, the direct current conversion unit is controlled to enter a shutdown state. Because the characteristic harmonic component is a harmonic component of which the inverter unit is coupled to the direct-current conversion unit, communication faults between the direct-current conversion unit and the inverter unit cannot influence the characteristic harmonic component, namely cannot influence the judging result, and therefore the shutdown method of the direct-current conversion unit can avoid the influence on shutdown of the direct-current conversion unit due to unreliable communication between the inverter unit and the direct-current conversion unit.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to an inverter, a direct current conversion unit and a shutdown method thereof.
Background
In the inverter, if the direct-current conversion unit and the inversion unit are independently arranged, the direct-current conversion unit and the inversion unit are communicated and transmitted in a wired or power carrier communication mode; for example, when the inverter unit is in fault shutdown, the inverter unit can utilize communication connection with the direct current conversion unit to shutdown the direct current conversion unit by the issued alternating current fault instruction, so that electric power accidents are avoided, and electric power safety of the inverter is further ensured.
However, when communication faults such as abnormal communication or communication interruption occur between the two, the shutdown command cannot be issued to the dc conversion unit, so that the dc conversion unit is still in a working state, and thus the inverter may be damaged.
Therefore, how to avoid the communication unreliability between the inversion unit and the dc conversion unit and the influence on the shutdown of the dc conversion unit is a technical problem to be solved.
Disclosure of Invention
In view of the above, the present invention provides an inverter, a dc conversion unit and a shutdown method thereof, so as to avoid the influence of unreliable communication between the inverter unit and the dc conversion unit caused by shutdown of the dc conversion unit.
In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:
a first aspect of the present application provides a shutdown method of a dc conversion unit, including:
judging whether the direct current conversion unit needs to be stopped or not through characteristic harmonic components in the direct current conversion unit; the characteristic harmonic component is a harmonic component of the inverter unit coupled to the direct current conversion unit;
if the direct current conversion unit needs to be stopped, controlling the direct current conversion unit to enter a stopping state;
and if the direct current conversion unit does not need to be stopped, controlling the direct current conversion unit to be in a normal working state.
Optionally, determining, by the characteristic harmonic component in the dc conversion unit, whether the dc conversion unit needs to be stopped includes:
extracting the characteristic harmonic component from any pole-to-ground voltage on one of two sides of the direct current conversion unit, and judging whether the amplitude of the characteristic harmonic component is larger than a preset amplitude;
if the amplitude of the characteristic harmonic component is smaller than or equal to the preset amplitude, judging that the direct current conversion unit needs to be stopped;
and if the amplitude of the characteristic harmonic component is larger than the preset amplitude, judging that the direct current conversion unit does not need to be stopped.
Optionally, the characteristic harmonic component is a third harmonic component.
Optionally, the working conditions of the direct current conversion unit when the direct current conversion unit needs to be stopped are as follows: the inverter unit is stopped, or the inverter unit requires the direct current conversion unit to be stopped.
Optionally, controlling the dc conversion unit to enter a shutdown state includes:
stopping the direct current conversion of the direct current conversion unit and cutting off the connection between the direct current conversion unit and the inversion unit.
Optionally, stopping the dc conversion of the dc conversion unit and cutting off the connection between the dc conversion unit and the inverter unit, including:
closing the driving output of a controller in the direct current conversion unit; or,
and cutting off the power supply input of a driving module in the direct current conversion unit.
Optionally, the first side of the dc conversion unit is connected to the dc side of the inverter unit through a dc bus;
the inversion unit couples the characteristic harmonic component to the direct current conversion unit by injecting a common mode signal including the characteristic harmonic component to the direct current bus midpoint.
A second aspect of the present application provides a dc conversion unit, including: the direct current conversion module and the shutdown judgment module; wherein:
the shutdown judgment module is arranged between any pole of one of two sides of the direct current conversion module and the ground, the shutdown judgment module is connected with the direct current conversion module, and the shutdown judgment module is used for executing the shutdown method of the direct current conversion unit according to any one of the first aspect of the application.
Optionally, the dc conversion module includes: the direct current conversion circuit, the driving module, the controller and the connecting switch; wherein:
the direct-current conversion circuit is connected with the inversion unit through the connecting switch;
the controller is respectively connected with each power switch and the connecting switch in the direct current conversion circuit through the driving module;
the controller is used for realizing direct current conversion by controlling the on-off of the power switches, and controlling the disconnection or connection between the direct current conversion circuit and the inversion unit by controlling the on-off of the connecting switch.
Optionally, the shutdown judging module is connected with a signal end of the controller or an enabling end of the driving module.
Optionally, the shutdown determination module is integrated with the controller.
Optionally, the shutdown judging module includes: the voltage sampling module and the voltage detection module; wherein:
the voltage sampling module is arranged between any pole of one of two sides of the direct current conversion module and the ground, the output end of the voltage sampling module is connected with the detection end of the voltage detection module, and the output end of the voltage detection module is connected with the direct current conversion module.
A third aspect of the present application provides an inverter, comprising: an inverter unit and at least one dc conversion unit as described in any one of the second aspects of the present application; wherein:
the first side of the direct current conversion unit is connected with the direct current side of the inversion unit;
the second side of the direct current conversion unit is connected with a direct current power supply.
Optionally, the inversion unit and all the direct current conversion units are arranged in the same box body, and the direct current conversion units are in communication connection with the inversion unit; or,
the inversion unit is arranged on an independent box body; all the direct current conversion units are arranged in an independent box body, or each direct current conversion unit is respectively arranged in an independent box body.
Optionally, the direct current power supply is a photovoltaic string or an energy storage system.
According to the technical scheme, the invention provides a shutdown method of a direct current conversion unit. In the shutdown method of the direct current conversion unit, whether the direct current conversion unit needs to be shutdown or not is judged through characteristic harmonic components in the direct current conversion unit, and when the direct current conversion unit needs to be shutdown, the direct current conversion unit is controlled to enter a shutdown state. Because the characteristic harmonic component is a harmonic component of which the inverter unit is coupled to the direct-current conversion unit, communication faults between the direct-current conversion unit and the inverter unit cannot influence the characteristic harmonic component, namely cannot influence the judging result, and therefore the shutdown method of the direct-current conversion unit can avoid the influence on shutdown of the direct-current conversion unit due to unreliable communication between the inverter unit and the direct-current conversion unit.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
Fig. 1 and fig. 2 are two schematic flow diagrams of a shutdown method of a dc conversion unit provided in the present application;
fig. 3 and fig. 4 are schematic diagrams of two structures of the dc conversion unit provided in the present application;
fig. 5a and 5b are schematic views of two structures of the inverter provided in the present application, respectively.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
In this application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In order to avoid the influence of unreliable communication between the inversion unit and the direct current conversion unit on the shutdown of the direct current conversion unit, the application provides a shutdown method of the direct current conversion unit, and the specific flow of the shutdown method is shown in fig. 1, and the method comprises the following steps:
s110, judging whether the direct current conversion unit needs to be stopped or not through characteristic harmonic components in the direct current conversion unit.
If the dc conversion unit needs to be stopped, step S120 is executed; if the dc conversion unit does not need to be stopped, step S130 is performed.
The characteristic harmonic component is a harmonic component of which the inversion unit is coupled to the direct current conversion unit; in practical application, the first side of the dc conversion unit is connected to the dc side of the inverter unit through a dc bus, and the inverter unit couples the characteristic harmonic component to the dc conversion unit by injecting a common mode signal including the characteristic harmonic component to the midpoint of the dc bus.
Optionally, the working condition that the direct current conversion unit needs to be stopped may be: the inverter unit is stopped, such as: stopping the machine due to insulation faults, overvoltage and undervoltage faults, overload faults or over-temperature faults; the method can also be as follows: the inverter unit requires the direct current conversion unit to stop, and is not particularly limited herein, and is within the scope of protection of the present application.
In general, the inversion unit injects a common mode signal into the midpoint of the dc bus, but when the inversion unit is stopped, the common mode signal is not injected any more, so that the characteristic harmonic component coupled to the dc conversion unit is also lost; when the inversion unit is requesting the direct current conversion unit to stop, the inversion unit actively stops injecting the common mode signal to the midpoint of the direct current bus, namely the common mode signal disappears, so that the characteristic harmonic component coupled to the direct current conversion unit also disappears; therefore, whether the direct current conversion unit needs to be stopped or not can be judged through the characteristic harmonic component in the direct current conversion unit.
Alternatively, the common mode signal may be a common mode current or a common mode voltage, which is not specifically limited herein, and may be within the scope of protection of the present application as the case may be.
Preferably, the characteristic harmonic component is a third harmonic component; in practical applications, including but not limited to the preferred embodiments, the present invention is not limited thereto, and the present invention can be applied to any situation as appropriate.
S120, controlling the direct current conversion unit to enter a stop state.
The method for controlling the direct current conversion unit to enter the shutdown state specifically comprises the following steps: stopping the direct current conversion of the direct current conversion unit and cutting off the connection between the direct current conversion unit and the inversion unit.
Alternatively, the direct current conversion of the direct current conversion unit can be stopped by closing the driving output of the controller in the direct current conversion unit and also by cutting off the power supply input of the driving module in the direct current conversion unit, and the connection between the direct current conversion unit and the inversion unit is cut off; in practical applications, including but not limited to the above embodiments, the present invention is not limited to the above embodiments, and may be applied to the protection scope of the present application as the case may be.
S130, controlling the direct current conversion unit to be in a normal working state.
It should be noted that, the specific manner of controlling the dc conversion unit in the normal working state is the same as that of the prior art, and will not be described here again.
Because the characteristic harmonic component is a harmonic component of which the inverter unit is coupled to the direct-current conversion unit, communication faults between the direct-current conversion unit and the inverter unit cannot influence the characteristic harmonic component, namely cannot influence the judging result, and therefore the shutdown method of the direct-current conversion unit can avoid the influence on shutdown of the direct-current conversion unit due to unreliable communication between the inverter unit and the direct-current conversion unit.
In another embodiment of the present application, as shown in fig. 2, step S110 specifically includes the following steps:
s210, extracting a characteristic harmonic component from the ground voltage of any pole of two sides of the direct current conversion unit, and judging whether the amplitude of the characteristic harmonic component is larger than a preset amplitude.
If the amplitude of the characteristic harmonic component is less than or equal to the preset amplitude, executing step S220; if the amplitude of the characteristic harmonic component is greater than the preset amplitude, step S230 is performed.
S220, stopping the direct current conversion unit.
S230, the direct current conversion unit does not need to be stopped.
The inverter unit injects a common mode signal comprising characteristic harmonic components to the middle point of the direct current bus, so that the characteristic harmonic components are coupled on any pole of the first side of the direct current conversion unit connected with the direct current bus; the midpoint of the direct current side of the direct current conversion unit is the direct current offset, so the second side of the direct current conversion unit is also coupled with the characteristic harmonic component.
In practical application, there may be a characteristic harmonic component generated by other factors in the ground voltage of any pole on both sides of the dc conversion unit, so as to eliminate the judgment of other factors on whether the inversion unit is stopped, a preset amplitude is set, and whether the inversion unit is stopped is judged by judging the amplitude of the characteristic harmonic component, so as to eliminate the influence caused by other factors.
It should be noted that, the preset amplitude is the amplitude preset according to the influence of other factors, the specific value is not limited here, and the preset amplitude is within the protection scope of the application according to the specific situation; the extraction of the characteristic harmonic component and the calculation of the amplitude of the characteristic harmonic component can be realized by a software algorithm, and the software algorithm is in the prior art and is not described in detail herein.
In another embodiment of the present application, the filtering unit may filter the characteristic harmonic component generated by other factors and coupled to the dc conversion unit, and only retain the required characteristic harmonic component, and then determine whether the dc conversion unit is stopped by detecting the characteristic harmonic component.
The present application provides a dc conversion unit, whose structure is shown in fig. 3, comprising: a direct current conversion module 10 and a shutdown judgment module 20.
In this embodiment of the dc conversion unit, the shutdown determination module 20 is disposed between any one of the two sides of the dc conversion module 10 and the ground GND, the shutdown determination module 20 is connected to the dc conversion module 10, and the shutdown determination module 20 is configured to perform the shutdown method of the dc conversion unit as provided in the above embodiment.
In another embodiment of the present application, as shown in fig. 3, the dc conversion module 10 includes: the direct current conversion circuit 11, the controller 12, the driving module 13 and the connection switch S.
Wherein the second side of the dc conversion circuit 11 is used as the second side of the dc conversion module 10, and the first side of the dc conversion circuit 11 is connected to the dc side of the inverter unit through the connection switch S; the output end of the controller 12 is connected to the control end of the connection switch S and the control end of each power switch Q in the dc conversion circuit 11 through the driving module 13.
In operation, the controller 12 controls the on/off of the power switches Q to realize dc conversion, and controls the on/off of the connection switch S to control the disconnection or connection between the dc conversion circuit 11 and the inverter unit.
Optionally, the switch in the dc conversion circuit 11 may be a MOS transistor or an IGBT power transistor, and in practical application, including but not limited to this embodiment, the present disclosure is not limited to specific embodiments, and may be within the scope of protection of the present disclosure as the case may be.
Optionally, the connection switch S may be an NMOS tube or a PMOS tube, or may be a relay; in practical applications, including but not limited to the above embodiments, the present invention is not limited to the above embodiments, and may be applied to the protection scope of the present application as the case may be.
Alternatively, the dc conversion circuit 11 may be a two-level topology as shown in fig. 3, or may be a multi-level topology, such as a three-level topology, which is not limited herein, and may be within the scope of protection of the present application as the case may be.
In addition, in practical application, the dc conversion circuit 11 of the two-level topology and the dc conversion circuit 11 of the three-level topology have various embodiments, which are not limited herein, and are within the protection scope of the present application as the case may be; moreover, these embodiments are well established in the art and will not be described in detail herein.
In this embodiment, the shutdown determination module 20 may be coupled to a signal terminal of the controller 12, as shown in FIG. 3; if the shutdown determination module 20 determines that the dc conversion unit needs to be shutdown, the shutdown determination module 20 notifies the controller 12 to output a driving signal to shutdown so as to turn off the connection switch S and each power switch Q.
In this embodiment, the shutdown determination module 20 may be connected to the enable end of the drive module 13, as shown in FIG. 4; if the shutdown judging module 20 judges that the dc conversion unit needs to be shutdown, the shutdown judging module 20 cuts off the power supply input of the driving module 13, so that the driving module 13 stops working, and the driving signals issued by the controller 12 to the connection switch S and each power switch Q cannot be transmitted to the corresponding switch, that is: the connection switch S and the respective power switches Q are turned off indirectly.
The above embodiments of stopping the dc conversion unit by only two stopping judging modules are not specifically limited herein, and they are all within the scope of protection of the present application as the case may be.
Preferably, the shutdown determination module 20 is integrated into the controller 12; in practical applications, including but not limited to the preferred embodiments, the present invention is not limited thereto, and the present invention can be applied to any situation as appropriate.
In another embodiment of the present application, as shown in fig. 3 or 4, the shutdown determination module 20 includes: a voltage sampling module 21 and a voltage detection module 22; wherein: the voltage sampling module 21 is disposed between any pole of two sides of the dc conversion module 10 and the ground GND, and an output end of the voltage sampling module 21 is connected to a detection end of the voltage detection module 22, and an output end of the voltage detection module 22 is connected to the dc conversion module 10.
In operation, the voltage sampling module 21 samples the voltage to ground of any one of the two sides of the dc conversion module 10, and inputs the sampled voltage to ground into the value voltage detection module 22; the voltage detection module 22 extracts a characteristic harmonic component from this voltage and performs the shutdown method of the dc conversion unit provided by the above-described embodiment.
In another embodiment of the present application, a filtering module may be disposed in the voltage detecting module 22, and is configured to filter out the characteristic harmonic components generated by other factors, only retain the required characteristic harmonic components, and then determine whether the dc converting unit is stopped by detecting the characteristic harmonic components.
Another embodiment of the present application provides an inverter, the specific structure of which can be shown in fig. 5a or fig. 5b (only one dc conversion unit 100 is shown in the drawing as an example), and the inverter specifically includes: the inverter unit 200 and at least one dc conversion unit 100 as provided in the above-described embodiments.
In the inverter, a first side of the dc conversion unit 100 is connected to a dc side of the inverter unit 200; a second side of the dc conversion unit 100 is connected to a dc power supply.
In another embodiment of the present application, as shown in fig. 5a, the inverter unit and all the dc conversion units are disposed in the same box, and the box is shown in the implementation block in fig. 5 a; the dc conversion unit 100 is communicatively connected to the inverter unit 200, as shown by the dashed lines in fig. 5 a.
Alternatively, the dc power source may be a string of photovoltaic modules; the system may also be an energy storage system, which is not specifically limited herein, and may be within the scope of the present application as the case may be.
In another embodiment of the present application, as shown in fig. 5b, the inverter units are disposed in one independent box, and all the dc conversion units are disposed in one independent box, or each dc conversion unit is disposed in one independent box respectively; wherein the independent box is shown as an implementation block in fig. 5 b.
The features described in the various embodiments of the present disclosure may be interchanged or combined with each other in the above description of the disclosed embodiments to enable those skilled in the art to make or use the present application. The above description is only of the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. While the invention has been described with reference to preferred embodiments, it is not intended to be limiting. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention or modifications to equivalent embodiments using the methods and technical contents disclosed above, without departing from the scope of the technical solution of the present invention. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (14)
1. A method of shutting down a dc conversion unit, comprising:
judging whether the direct current conversion unit needs to be stopped or not through characteristic harmonic components in the direct current conversion unit; the characteristic harmonic component is a harmonic component of which the inversion unit is coupled to the direct current conversion unit;
if the direct current conversion unit needs to be stopped, controlling the direct current conversion unit to enter a stopping state;
if the direct current conversion unit does not need to be stopped, the direct current conversion unit is controlled to be in a normal working state;
wherein, through the characteristic harmonic component in the direct current conversion unit, judge whether the direct current conversion unit needs shut down, include:
extracting the characteristic harmonic component from any pole-to-ground voltage on one of two sides of the direct current conversion unit, and judging whether the amplitude of the characteristic harmonic component is larger than a preset amplitude;
if the amplitude of the characteristic harmonic component is smaller than or equal to the preset amplitude, judging that the direct current conversion unit needs to be stopped;
and if the amplitude of the characteristic harmonic component is larger than the preset amplitude, judging that the direct current conversion unit does not need to be stopped.
2. The method of shutting down a dc conversion unit according to claim 1, wherein the characteristic harmonic component is a third harmonic component.
3. The method for shutting down a dc conversion unit according to any one of claims 1-2, wherein the conditions under which the dc conversion unit is required to be shut down are: the inverter unit is stopped, or the inverter unit requires the direct current conversion unit to be stopped.
4. Method for shutting down a dc conversion unit according to any one of claims 1-2, characterized in that controlling the dc conversion unit into a shut down state comprises:
stopping the direct current conversion of the direct current conversion unit and cutting off the connection between the direct current conversion unit and the inversion unit.
5. The method of stopping a dc conversion unit according to claim 4, wherein stopping dc conversion of the dc conversion unit and cutting off connection between the dc conversion unit and the inverter unit, comprises:
closing the driving output of a controller in the direct current conversion unit; or,
and cutting off the power supply input of a driving module in the direct current conversion unit.
6. The method of shutting down a dc conversion unit according to any one of claims 1-2, wherein the first side of the dc conversion unit is connected to the dc side of the inverter unit by means of a dc bus;
the inversion unit couples the characteristic harmonic component to the direct current conversion unit by injecting a common mode signal including the characteristic harmonic component to the direct current bus midpoint.
7. A direct current conversion unit, characterized by comprising: the direct current conversion module and the shutdown judgment module; wherein:
the shutdown judgment module is arranged between any pole of one of two sides of the direct current conversion module and the ground, the shutdown judgment module is connected with the direct current conversion module, and the shutdown judgment module is used for executing the shutdown method of the direct current conversion unit according to any one of claims 1-6.
8. The direct current conversion unit according to claim 7, wherein the direct current conversion module includes: the direct current conversion circuit, the driving module, the controller and the connecting switch; wherein:
the direct-current conversion circuit is connected with the inversion unit through the connecting switch;
the controller is respectively connected with each power switch and the connecting switch in the direct current conversion circuit through the driving module;
the controller is used for realizing direct current conversion by controlling the on-off of the power switches, and controlling the disconnection or connection between the direct current conversion circuit and the inversion unit by controlling the on-off of the connecting switch.
9. The dc conversion unit according to claim 8, wherein the shutdown determination module is connected to a signal terminal of the controller or an enable terminal of the driving module.
10. The direct current conversion unit according to claim 8, wherein the shutdown determination module is integrated with the controller.
11. The direct current conversion unit according to any one of claims 7 to 10, wherein the shutdown determination module includes: the voltage sampling module and the voltage detection module; wherein:
the voltage sampling module is arranged between any pole of one of two sides of the direct current conversion module and the ground, the output end of the voltage sampling module is connected with the detection end of the voltage detection module, and the output end of the voltage detection module is connected with the direct current conversion module.
12. An inverter, comprising: an inverter unit and at least one dc conversion unit according to any one of claims 7-11; wherein:
the first side of the direct current conversion unit is connected with the direct current side of the inversion unit;
the second side of the direct current conversion unit is connected with a direct current power supply.
13. The inverter according to claim 12, wherein the inverter unit and all the dc conversion units are provided in the same case, the dc conversion units being communicatively connected to the inverter unit; or,
the inversion unit is arranged on an independent box body; all the direct current conversion units are arranged in an independent box body, or each direct current conversion unit is respectively arranged in an independent box body.
14. The inverter of claim 12 or 13, wherein the dc power source is a photovoltaic string or an energy storage system.
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| US11296650B2 (en) * | 2006-12-06 | 2022-04-05 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
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