CN110880741A - Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system - Google Patents
Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system Download PDFInfo
- Publication number
- CN110880741A CN110880741A CN201911212640.8A CN201911212640A CN110880741A CN 110880741 A CN110880741 A CN 110880741A CN 201911212640 A CN201911212640 A CN 201911212640A CN 110880741 A CN110880741 A CN 110880741A
- Authority
- CN
- China
- Prior art keywords
- symmetrical
- circuit
- level
- booster circuit
- level booster
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Inverter Devices (AREA)
Abstract
The invention provides an inversion system and an input misconnection detection method of a symmetrical three-level booster circuit thereof, wherein the method comprises the following steps: respectively controlling each symmetrical three-level booster circuit in the inverter system to independently operate in a PWM (pulse width modulation) working mode; before each symmetrical three-level booster circuit independently operates in a PWM working mode, first voltages corresponding to each symmetrical three-level booster circuit are respectively detected; when each symmetrical three-level booster circuit operates in a PWM working mode independently, second voltages corresponding to each symmetrical three-level booster circuit are detected respectively; if the corresponding difference value between at least one first voltage and at least one second voltage exceeds the preset range, judging that the corresponding symmetrical three-level booster circuit has an input misconnection fault; the situation that the symmetrical three-level booster circuit is damaged due to grid-connected operation of the system when the positive electrode and the negative electrode on the direct current side of the symmetrical three-level booster circuit have failure misconnection faults is avoided, and therefore the safety of the inverter system is improved.
Description
Technical Field
The invention belongs to the technical field of power electronics, and particularly relates to an inverter system and an input misconnection detection method of a symmetrical three-level booster circuit of the inverter system.
Background
In order to increase the power generation capacity, a photovoltaic inverter system generally adopts a plurality of boosting circuits connected in parallel to an inverter circuit, as shown in fig. 1, the output end of the inverter circuit is connected to a power grid or a load.
When the BOOST circuit applied to the photovoltaic inverter system is a symmetrical three-level BOOST circuit, as shown in fig. 2, the symmetrical three-level BOOST circuit is provided, wherein D1 and D2 are inverse parallel diodes of the switching tube, and D3 and D6 are bypass diodes. In addition, the four diodes D1, D2, D3 and D6 are generally power frequency rectifier tubes, the reverse recovery current is large, and when high-frequency current passes through the reverse recovery current, overheating failure is easy to occur.
In each symmetrical three-level BOOST circuit, it is usually connected in parallel into M (M ≧ 1) strings of photovoltaic strings. When the photovoltaic string is normally connected, namely PV + and PV-of the M photovoltaic strings are respectively and correspondingly connected to a direct-current side positive electrode DC + and a direct-current side negative electrode DC-of the same symmetrical three-level BOOST circuit, diodes D1, D2, D3 and D6 in the photovoltaic string are free of high-frequency current, and the symmetrical three-level BOOST circuit works normally; when the input end of a certain symmetrical three-level BOOST circuit is connected with the positive pole DC + of the direct current side only or connected with the negative pole DC-of the direct current side only in a wrong connection mode, the symmetrical three-level BOOST circuit still works, high-frequency currents exist in the diodes D1, D2, D3 and D6, and if the diodes are overheated and fail, the photovoltaic inverter system can be further failed.
Disclosure of Invention
In view of this, an object of the present invention is to provide an inverter system and a method for detecting an input misconnection of a symmetrical three-level BOOST circuit thereof, so as to solve the problem that when the input end of the symmetrical three-level BOOST circuit is misconnected only to the positive electrode of the dc side or only to the negative electrode of the dc side, the symmetrical three-level BOOST circuit still works, which causes a high-frequency current to exist in the diode, and if an overheat failure occurs, the photovoltaic inverter system will further fail.
The invention discloses a method for detecting input misconnection of a symmetrical three-level booster circuit of an inverter system, which comprises the following steps:
respectively controlling each symmetrical three-level booster circuit in the inverter system to independently operate in a PWM (pulse width modulation) working mode; before each symmetrical three-level booster circuit in the inverter system independently operates in a PWM (pulse width modulation) working mode, respectively detecting the voltage difference of a direct current bus of the inverter system and a first voltage corresponding to each symmetrical three-level booster circuit; when each symmetrical three-level booster circuit independently operates in a PWM (pulse-width modulation) working mode, respectively detecting the voltage difference of a direct-current bus of the inverter system as second voltages corresponding to each symmetrical three-level booster circuit;
judging whether the corresponding difference value between the first voltage and the second voltage corresponding to each symmetrical three-level booster circuit is within a preset range or not;
and if at least one corresponding difference value exceeds the preset range, judging that the corresponding symmetrical three-level booster circuit has an input misconnection fault.
Optionally, respectively controlling each symmetrical three-level boost circuit in the inverter system to independently operate in a PWM operating mode includes:
and outputting PWM control signals to each symmetrical three-level booster circuit in the inverter system one by one, and outputting driving closing signals to other symmetrical three-level booster circuits while outputting the PWM control signals to each symmetrical three-level booster circuit.
Optionally, after determining that the corresponding symmetric three-level boost circuit has an input misconnection fault, the method further includes:
and generating and outputting a misconnection fault signal.
Optionally, the misconnection fault signal includes identification information of a symmetric three-level boost circuit with an input misconnection fault.
Optionally, after determining that the corresponding symmetric three-level boost circuit has an input misconnection fault, the method further includes:
and controlling the inverter system to stop grid connection.
Optionally, after determining whether the corresponding difference between the first voltage and each of the second voltages is within a preset range, the method further includes:
and if all the corresponding difference values are within the preset range, judging that all the symmetrical three-level booster circuits have no input misconnection fault.
Optionally, after it is determined that no input misconnection fault exists in each of the symmetric three-level boost circuits, the method further includes:
and controlling the inverter system to operate in a grid-connected mode.
A second aspect of the present invention discloses an inverter system, including: the voltage-boosting circuit comprises a controller, an inverter circuit and a plurality of symmetrical three-level booster circuits; wherein:
the output ends of the symmetrical three-level booster circuits are connected in parallel, and the connecting point is connected with the direct current side of the inverter circuit;
the alternating current side of the inverter circuit is connected with a load or a power grid;
each output end of the controller is respectively connected with the control end of the inverter circuit and the control end of each symmetrical three-level booster circuit through corresponding drive circuits;
the controller is used for executing the input misconnection detection method of the symmetrical three-level booster circuit of the inverter system disclosed by the first aspect of the invention.
A third aspect of the present invention discloses an inverter system, comprising: a main controller, an inverter and a plurality of DC/DC converters; wherein:
the main circuit of the DC/DC converter is a symmetrical three-level booster circuit;
the output ends of the symmetrical three-level booster circuits are connected in parallel, and the connecting point is connected with the direct current side of the main circuit of the inverter;
the alternating current side of the main circuit of the inverter is connected with a load or a power grid;
the main controller is used for executing the method for detecting the input misconnection of the symmetrical three-level booster circuit of the inverter system according to any one of the first aspect of the invention.
Optionally, the main controller is a controller inside the inverter and is in communication connection with controllers inside the DC/DC converters;
alternatively, the main controller is an independent system controller and is connected to the controller inside the inverter and the controllers inside the DC/DC converters in a communication manner.
Optionally, the method further includes: at least one combiner box;
the output end of the combiner box is connected with the direct current side of the main circuit of the inverter;
and each input end of the combiner box is respectively connected with the output end of the corresponding symmetrical three-level booster circuit.
From the above technical solution, the input misconnection detection method for the symmetrical three-level boost circuit of the inverter system provided by the present invention includes: respectively controlling each symmetrical three-level booster circuit in the inverter system to independently operate in a PWM (pulse width modulation) working mode; before each symmetrical three-level booster circuit independently operates in a PWM working mode, the voltage difference of a direct current bus of an inverter system is respectively detected and used as a first voltage corresponding to each symmetrical three-level booster circuit; when each symmetrical three-level booster circuit independently operates in a PWM (pulse width modulation) working mode, respectively detecting the voltage difference of a direct current bus of the inverter system as second voltages corresponding to each symmetrical three-level booster circuit; if the corresponding difference value between at least one first voltage and at least one second voltage exceeds the preset range, judging that the corresponding symmetrical three-level booster circuit has an input misconnection fault; the situation that the symmetrical three-level booster circuit is damaged due to the fact that an inverter in the inverter system still runs in a grid-connected mode when positive and negative electrodes on the direct current side of the symmetrical three-level booster circuit have failure misconnection faults is avoided, and therefore safety of the inverter system is improved.
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 introduced below, and it is obvious that the drawings in the following description are 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 diagram of a photovoltaic inverter system provided by the prior art;
FIG. 2 is a schematic diagram of a prior art symmetrical three-level BOOST circuit;
fig. 3 is an input misconnection schematic diagram of a symmetric three-level boost circuit of an inverter system according to an embodiment of the present invention;
fig. 4 is an input misconnection schematic diagram of a symmetric three-level boost circuit of an inverter system according to an embodiment of the present invention;
fig. 5 is an input misconnection schematic diagram of a symmetric three-level boost circuit of an inverter system according to an embodiment of the present invention;
fig. 6 is a flowchart of an input misconnection detection method for a symmetric three-level boost circuit of an inverter system according to an embodiment of the present invention;
fig. 7 is a flowchart of an input misconnection detection method for a symmetrical three-level boost circuit of an inverter system according to another embodiment of the present invention;
fig. 8 is a schematic diagram of an inverter system according to an embodiment of the present invention;
fig. 9 is a schematic diagram of an inverter system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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 protection scope of the present invention.
In this application, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiment of the invention provides an input misconnection detection method for a symmetrical three-level BOOST circuit of an inverter system, which aims to solve the problem that when the misconnection condition that the input end of the symmetrical three-level BOOST circuit is only connected with the positive pole of a direct current side or only connected with the negative pole of the direct current side occurs, the symmetrical three-level BOOST circuit still works, so that a diode has high-frequency current, and if the diode is overheated and fails, the photovoltaic inverter system can further fail.
Generally, the input misconnection detection method of the symmetrical three-level boost circuit is performed before the symmetrical three-level boost circuit enters a normal operation state, such as: the system installation and debugging stage is performed before the system is put into operation again after being overhauled, or before the system is operated every time, and the method is not particularly limited and is within the protection scope of the application. It should be noted that the input misconnection detection method of the symmetrical three-level boost circuit may be performed before each operation of the system as a preferred scheme.
The method for detecting the input misconnection of the symmetrical three-level booster circuit of the inverter system, as shown in fig. 6, includes the following steps:
s101, respectively controlling each symmetrical three-level booster circuit in an inverter system to independently operate in a PWM (pulse-width modulation) working mode; before each symmetrical three-level booster circuit independently operates in a PWM working mode, the voltage difference of a direct current bus of an inverter system is respectively detected and used as a first voltage corresponding to each symmetrical three-level booster circuit; and when each symmetrical three-level booster circuit independently operates in the PWM working mode, respectively detecting the voltage difference of the direct current bus of the inverter system as a second voltage corresponding to each symmetrical three-level booster circuit.
Specifically, a symmetrical three-level boost circuit is taken as an example for explanation, before the symmetrical three-level boost circuit is controlled to independently operate in a PWM working mode, a voltage difference of a dc bus of an inverter system is obtained as a first voltage corresponding to the symmetrical three-level boost circuit; and then controlling the symmetrical three-level booster circuit to independently operate in a PWM (pulse-width modulation) working mode and acquiring the voltage difference of a direct current bus of the inverter system at the moment as a second voltage corresponding to the symmetrical three-level booster circuit.
In practical applications, the dc bus voltage difference may be a voltage difference between a positive dc bus capacitance and a negative dc bus capacitance, that is, the first voltage is a voltage difference between the positive dc bus capacitance and the negative dc bus capacitance.
Before each symmetrical three-level booster circuit independently operates in the PWM working mode, each symmetrical three-level booster circuit is in a driving closing state. Specifically, before the ith symmetrical three-level boost circuit is controlled to independently operate in the PWM operating mode, when each of the symmetrical three-level boost circuits is in the drive off state, the voltage VC3 of the positive dc bus capacitor and the voltage VC4 of the negative dc bus capacitor are detected, and the dc bus voltage difference Vi1 is calculated as VC3-VC4, and Vi1 is used as the first voltage corresponding to the ith symmetrical three-level boost circuit.
When each symmetrical three-level booster circuit independently operates in the PWM working mode, only the symmetrical three-level booster circuit independently operates in the PWM working mode outputs voltage to the direct current bus, namely, the voltage of the direct current bus is the voltage of the symmetrical three-level booster circuit independently operating in the PWM working mode after two direct current bus capacitors are charged. The second voltage is also a voltage difference between the positive dc bus capacitor and the negative dc bus capacitor, and it should be noted that the second voltage and the first voltage are a voltage difference between the dc buses in different operating states of the inverter system. Specifically, when the ith symmetrical three-level boost circuit operates in the PWM operating mode independently, the voltage VC3 of the positive dc bus capacitor and the voltage VC4 of the negative dc bus capacitor are detected, and the dc bus voltage difference Vi2 is calculated as VC3-VC4, and Vi2 is used as the second voltage corresponding to the ith symmetrical three-level boost circuit.
In practical applications, the specific process of independently controlling each symmetrical three-level boost circuit in the inverter system related to step S101 to operate in the PWM operating mode may be:
and outputting PWM control signals to each symmetrical three-level booster circuit in the inverter system one by one, and outputting driving closing signals to other symmetrical three-level booster circuits while outputting the PWM control signals to each symmetrical three-level booster circuit.
It should be noted that the PWM control signals may be sequentially output to each of the symmetrical three-level boost circuits in the inverter system one by one, or may be randomly output to each of the symmetrical three-level boost circuits in the inverter system one by one until the PWM control signals are output to all the symmetrical three-level boost circuits.
S102, judging whether corresponding difference values between the first voltage and the second voltage corresponding to each symmetrical three-level booster circuit are within a preset range or not.
In practical applications, the specific process of step S102 may be to determine corresponding difference values between each first voltage and the corresponding second voltage, and then determine whether each corresponding difference value is within a preset range; the following may be performed for each second voltage: the method comprises the steps of firstly determining a corresponding difference value between a first voltage and a second voltage of a certain symmetrical three-level booster circuit, judging whether the corresponding difference value is within a preset range, and then executing the judgment on another symmetrical three-level booster circuit. Here, these are only two examples, and other specific processes capable of implementing step S102 are also within the scope of the present application. The preset range is determined according to actual conditions and is within the protection range of the application.
If at least one corresponding difference value exceeds the preset range, step S103 is executed.
And S103, judging that the corresponding symmetrical three-level booster circuit has an input misconnection fault.
The existence of input misconnection faults in the symmetrical three-level booster circuit comprises various conditions, such as:
(1) as shown in fig. 3: the DC side negative pole DC 1-of the 1 st symmetrical three-level BOOST circuit is suspended, and the DC side positive pole DC1+ of the 1 st symmetrical three-level BOOST circuit is connected with the positive pole of the photovoltaic string PV 3; the positive DC side DC2+ of the 2 nd symmetric three-level BOOST circuit is floating, and its negative DC side DC 2-is connected to the negative of the PV3 string. At this time, the 1 st symmetric three-level BOOST circuit and the 2 nd symmetric three-level BOOST circuit both have failure risks.
If the 1 st symmetric three-level BOOST circuit operates in the PWM operating mode independently, the current paths when the switching tubes Q11 and Q12 are turned on are: the direct current side positive electrode DC1+ → inductor L11 → switching tube Q11 → negative direct current bus capacitor C4 → diode D26 → direct current side negative electrode DC 2-; the current paths when the switching tubes Q11 and Q12 are closed are: the direct current side positive electrode DC1+ → inductance L11 → diode D14 → positive direct current bus capacitor C3 → negative direct current bus capacitor C4 → diode D26 → direct current side negative electrode DC 2-.
In an inverter system, an auxiliary power supply continuously takes power from the direct-current bus capacitors C3 and C4, and the discharging currents of the direct-current bus capacitors C3 and C4 are equal; when the 1 st symmetric three-level BOOST circuit operates in the PWM operating mode independently, the current of the negative dc bus capacitor C4 is greater than the current of the positive dc bus capacitor C3 during the charging process of the dc bus capacitor, so the voltage of the positive dc bus capacitor C3 continuously decreases, the voltage of the negative dc bus capacitor C4 continuously increases, V1 < 0 and the negative value thereof continuously increases. Similarly, when the 2 nd symmetric three-level BOOST circuit operates in the PWM operating mode independently, V2 is greater than 0 and the positive value thereof continuously increases, where V1 is the corresponding difference between the first voltage and the second voltage corresponding to the 1 st symmetric three-level BOOST circuit, and V2 is the corresponding difference between the first voltage and the second voltage corresponding to the 2 nd symmetric three-level BOOST circuit.
(2) As shown in fig. 4: the positive pole DC2+ of the direct current side of the 2 nd symmetrical three-level BOOST circuit is suspended, and the negative pole DC 2-of the direct current side of the 2 nd symmetrical three-level BOOST circuit is connected with the negative pole of the photovoltaic string PV 3; the positive pole DC1+ of the direct current side of the 1 st symmetrical three-level BOOST circuit is respectively connected with the positive poles of the photovoltaic string PV3 and PV 1; the negative DC side DC 1-is connected to the negative pole of the PV string 1. At this time, the 2 nd symmetric three-level BOOST circuit has a failure risk.
(3) As shown in fig. 5: the positive pole DC1+ of the direct current side of the 1 st symmetrical three-level BOOST circuit is connected with the positive pole of the photovoltaic group string PV3, and the negative pole DC1+ of the direct current side is suspended; the positive DC side DC2+ of the 2 nd symmetrical three-level BOOST circuit is connected to the positive terminal of the PV string 2, and its negative DC side DC 2-is connected to the negative terminals of the PV strings PV3 and PV2, respectively. At this time, the 1 st symmetric three-level BOOST circuit has a failure risk.
Fig. 4 and 5 are similar to fig. 3 in connection manner, and the working process and principle thereof are also similar, and are not described again.
If the input wiring manner of the symmetric three-level boost circuit is any one of the three examples, the symmetric three-level boost circuit has a failure risk, and therefore, the detection can be performed by the input misconnection detection method provided by the embodiment.
In this embodiment, if there is at least one corresponding difference between the first voltage and the second voltage that exceeds the preset range, it is determined that the corresponding symmetric three-level boost circuit has an input misconnection fault, so that the problem that a diode in the symmetric three-level boost circuit has a high-frequency current when the positive electrode and the negative electrode on the direct-current side of the symmetric three-level boost circuit have a failure misconnection fault is avoided, and the safety of the inverter system is further improved.
In order to improve the safety of the inverter system, after it is determined that any one of the symmetrical three-level voltage boosting circuits has an input misconnection fault, corresponding protection measures can be implemented to protect the symmetrical three-level voltage boosting circuits. In practical applications, after step S103, the method further includes: and S201, controlling the inverter system to stop grid connection.
Alternatively, after step S103, the method further includes: and S301, generating and outputting a misconnection fault signal. The misconnection fault signal comprises identification information of the symmetrical three-level booster circuit with the input misconnection fault, so that a worker can determine the symmetrical three-level booster circuit with the input misconnection fault according to the identification information, further can carry out targeted further maintenance operation, and the symmetrical three-level booster circuit is prevented from failing after an inverter system is connected to the grid and works when the symmetrical three-level booster circuit has the failed input misconnection fault.
It should be noted that after step S103, only step S201 or step S301 may be executed, or step S201 and step S301 may be executed, which is not specifically limited herein and is within the scope of the present application. When step S201 and step S301 are executed, step S201 and step S301 may be executed successively or simultaneously, which is not specifically limited herein and is within the protection scope of the present application.
It should be further noted that, on the basis of the embodiment in fig. 6, referring to fig. 7, after step S102, if each corresponding difference value is within the preset range, the method further includes: and S104, judging that the symmetrical three-level booster circuits do not have input misconnection faults.
When each three level boost circuit of symmetry does not all have the input misconnection trouble, the problem that the diode has high frequency current to flow through can not appear in each three level boost circuit of symmetry in normal operating, and then after judging that each three level boost circuit of symmetry does not all have the input misconnection trouble, still can include: and controlling the inverter system to operate in a grid-connected mode.
In the practical application scene, the inversion system is explained as follows:
the inverter system comprises N symmetrical three-level BOOST circuits, and the specific control process is as follows:
1. before the 1 st symmetrical three-level BOOST circuit operates in the PWM operating mode independently, a dc bus voltage difference V11 is detected, which is a voltage difference between a positive dc bus capacitance and a negative dc bus capacitance, that is, V11 ═ VC3-VC4, where VC3 is a voltage of the positive dc bus capacitance and VC4 is a voltage of the negative dc bus capacitance.
2. And controlling the 1 st symmetrical three-level BOOST circuit to independently operate in the PWM working mode, and keeping the other BOOST circuits driven to be closed, so that the other symmetrical three-level BOOST circuits except the 1 st symmetrical three-level BOOST circuit are not in the PWM working mode.
3. Detecting a direct current bus voltage difference V12, and calculating a change value of the direct current bus voltage difference, namely a corresponding difference V1 between a first voltage and a second voltage of the symmetrical three-voltage booster circuit is V11-V12; and then judging whether the variation value exceeds a preset range.
4. And (3) sequentially and repeatedly executing the processes of the steps 1 to 3 on the ith symmetrical three-level BOOST circuit, wherein i is more than 1 and less than or equal to N, and i is a positive integer.
In step 1, the dc bus voltage difference corresponding to the i-th symmetric three-level BOOST circuit is Vi1, and in step 3, the dc bus voltage difference corresponding to the i-th symmetric three-level BOOST circuit is Vi2, and the variation value of the dc bus voltage difference is Vi.
5. And if Vi exceeds a preset range, generating and outputting a misconnection fault signal, and stopping the grid connection of the inverter in the inverter system so as to ensure the normal operation of the inverter.
6. If V1-VN are all smaller than the preset range, the inverter is not failed and misconnected, and grid-connected operation of the inverter is controlled.
An embodiment of the present invention provides an inverter system, as shown in fig. 8, including: a controller 503, an inverter circuit 502 and a plurality of symmetrical three-level boost circuits 501; wherein:
the output ends of the symmetrical three-level booster circuits 501 are connected in parallel, the connecting point is connected with the direct current side of the inverter circuit 502, and the alternating current side of the inverter circuit 502 is connected with a load or a power grid.
The output ends of the controller 503 are respectively connected to the control end of the inverter circuit 502 and the control end of each of the symmetrical three-level boost circuits 501 through corresponding driving circuits.
According to the connection relationship of the devices, the inverter system is a group-series inverter system.
The controller 502 is configured to execute the input misconnection detection method for the symmetrical three-level boost circuit of the inverter system according to any of the embodiments, and the working process and principle of the input misconnection detection method refer to any of the embodiments, which is not described herein again.
An embodiment of the present invention provides an inverter system, as shown in fig. 9, including: a main controller (not shown in the figure), an inverter 602, and a plurality of DC/DC converters 601; wherein:
the main circuit of the DC/DC converter 601 is a symmetrical three-level boost circuit, the output ends of the symmetrical three-level boost circuits are connected in parallel, the connection point is connected to the main circuit DC side of the inverter 602, and the main circuit ac side of the inverter 602 is connected to the load or the grid.
The main controller is used for executing the input misconnection detection method of the symmetrical three-level booster circuit of the inverter system in any one of the embodiments. The working process and principle of the input misconnection detection method refer to any of the above embodiments, and are not described in detail herein.
In practical application, the main controller is a controller inside the inverter 602, and is connected to the controllers inside the DC/DC converters 601 in a communication manner; alternatively, the main controller is an independent system controller (not shown), and is connected to the controller inside the inverter 602 and the controllers inside the DC/DC converters 601 through communication.
In practical application, the inverter system further comprises: at least one combiner box.
The output end of the combiner box is connected to the main circuit dc side of the inverter 602, and each input end of the combiner box is connected to the output end of the corresponding symmetric three-level boost circuit. At this time, the inverter system is a centralized inverter system.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
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 (11)
1. An input misconnection detection method for a symmetrical three-level booster circuit of an inverter system is characterized by comprising the following steps:
respectively controlling each symmetrical three-level booster circuit in the inverter system to independently operate in a PWM (pulse width modulation) working mode; before each symmetrical three-level booster circuit independently operates in a PWM working mode, the voltage difference of a direct current bus of the inverter system is respectively detected and used as a first voltage corresponding to each symmetrical three-level booster circuit; when each symmetrical three-level booster circuit independently operates in a PWM (pulse-width modulation) working mode, respectively detecting the voltage difference of a direct-current bus of the inverter system as second voltages corresponding to each symmetrical three-level booster circuit;
judging whether the corresponding difference value between the first voltage and the second voltage corresponding to each symmetrical three-level booster circuit is within a preset range or not;
and if at least one corresponding difference value exceeds the preset range, judging that the corresponding symmetrical three-level booster circuit has an input misconnection fault.
2. The method of claim 1, wherein the step of controlling each of the three symmetrical level boost circuits in the inverter system to operate in the PWM mode independently comprises:
and outputting PWM control signals to each symmetrical three-level booster circuit in the inverter system one by one, and outputting driving closing signals to other symmetrical three-level booster circuits while outputting the PWM control signals to each symmetrical three-level booster circuit.
3. The method of claim 1, wherein after determining that the corresponding symmetrical three-level boost circuit has the input misconnection fault, the method further comprises:
and generating and outputting a misconnection fault signal.
4. The method according to claim 3, wherein the misconnection fault signal includes identification information of the symmetrical three-level boost circuit having the misconnection fault.
5. The method for detecting the input misconnection of the symmetrical three-level boost circuit of the inverter system according to any one of claims 1 to 4, further comprising, after determining that there is an input misconnection fault in the corresponding symmetrical three-level boost circuit:
and controlling the inverter system to stop grid connection.
6. The method for detecting the input misconnection of the symmetrical three-level boost circuit of the inverter system according to any one of claims 1 to 4, wherein after determining whether the corresponding difference values between the first voltage and each of the second voltages are all within a predetermined range, the method further comprises:
and if all the corresponding difference values are within the preset range, judging that all the symmetrical three-level booster circuits have no input misconnection fault.
7. The method of claim 6, wherein after determining that no input misconnection fault exists in each of the three symmetrical voltage boosting circuits, the method further comprises:
and controlling the inverter system to operate in a grid-connected mode.
8. An inversion system, comprising: the voltage-boosting circuit comprises a controller, an inverter circuit and a plurality of symmetrical three-level booster circuits; wherein:
the output ends of the symmetrical three-level booster circuits are connected in parallel, and the connecting point is connected with the direct current side of the inverter circuit;
the alternating current side of the inverter circuit is connected with a load or a power grid;
each output end of the controller is respectively connected with the control end of the inverter circuit and the control end of each symmetrical three-level booster circuit through corresponding drive circuits;
the controller is used for executing the input misconnection detection method of the symmetrical three-level booster circuit of the inverter system as claimed in any one of claims 1 to 7.
9. An inversion system, comprising: a main controller, an inverter and a plurality of DC/DC converters; wherein:
the main circuit of the DC/DC converter is a symmetrical three-level booster circuit;
the output ends of the symmetrical three-level booster circuits are connected in parallel, and the connecting point is connected with the direct current side of the main circuit of the inverter;
the alternating current side of the main circuit of the inverter is connected with a load or a power grid;
the main controller is used for executing the input misconnection detection method of the symmetrical three-level booster circuit of the inverter system as claimed in any one of claims 1 to 7.
10. The inverter system of claim 9, wherein the master controller is a controller internal to the inverter and communicatively coupled to a controller internal to each DC/DC converter;
alternatively, the main controller is an independent system controller and is connected to the controller inside the inverter and the controllers inside the DC/DC converters in a communication manner.
11. The inverter system according to claim 9 or 10, further comprising: at least one combiner box;
the output end of the combiner box is connected with the direct current side of the main circuit of the inverter;
and each input end of the combiner box is respectively connected with the output end of the corresponding symmetrical three-level booster circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911212640.8A CN110880741B (en) | 2019-12-02 | 2019-12-02 | Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911212640.8A CN110880741B (en) | 2019-12-02 | 2019-12-02 | Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110880741A true CN110880741A (en) | 2020-03-13 |
| CN110880741B CN110880741B (en) | 2022-02-18 |
Family
ID=69729769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911212640.8A Active CN110880741B (en) | 2019-12-02 | 2019-12-02 | Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110880741B (en) |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102882227A (en) * | 2012-09-14 | 2013-01-16 | 江苏兆伏新能源有限公司 | High-power photovoltaic grid-connected inverter |
| CN103825299A (en) * | 2014-02-28 | 2014-05-28 | 深圳市长昊机电有限公司 | Grid-connected photovoltaic power generation system and control method thereof |
| CN203839977U (en) * | 2014-05-08 | 2014-09-17 | 上海理工大学 | Photovoltaic inverting device |
| CN203933039U (en) * | 2014-03-03 | 2014-11-05 | 苏州大学 | A kind of photovoltaic combining inverter |
| CN104765012A (en) * | 2015-04-21 | 2015-07-08 | 阳光电源股份有限公司 | Fault detection method, fault detection circuit and inverter |
| CN104810858A (en) * | 2015-05-27 | 2015-07-29 | 广西大学 | Control method for grid-connected power generation system of optical storage microgrid |
| CN105356513A (en) * | 2015-12-14 | 2016-02-24 | 阳光电源股份有限公司 | Inverter wiring error self-adaption method as well as device and application of method and photovoltaic system |
| CN105871324A (en) * | 2016-04-11 | 2016-08-17 | 厦门科华恒盛股份有限公司 | Independent MPPT tracking method for multi-branch input photovoltaic inverter system |
| CN106452137A (en) * | 2016-07-12 | 2017-02-22 | 江苏兆伏爱索新能源有限公司 | Control method of improving conversion efficiency of multiple maximum power point tracking (MPPT) inverters |
| CN107807305A (en) * | 2017-10-30 | 2018-03-16 | 阳光电源股份有限公司 | A kind of assembly type inverter Wiring detection method, apparatus and system |
| CN107843806A (en) * | 2017-10-30 | 2018-03-27 | 阳光电源股份有限公司 | A kind of Wiring detection method, device and photovoltaic generating system |
| US20180109136A1 (en) * | 2016-10-13 | 2018-04-19 | Schneider Electric It Corporation | Dc-link bus balancer |
| CN109510450A (en) * | 2018-12-27 | 2019-03-22 | 阳光电源股份有限公司 | A kind of reverse connecting protection method and photovoltaic generating system |
| CN110391676A (en) * | 2019-08-09 | 2019-10-29 | 阳光电源股份有限公司 | A kind of multichannel MPPT inverter and its control method |
-
2019
- 2019-12-02 CN CN201911212640.8A patent/CN110880741B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102882227A (en) * | 2012-09-14 | 2013-01-16 | 江苏兆伏新能源有限公司 | High-power photovoltaic grid-connected inverter |
| CN103825299A (en) * | 2014-02-28 | 2014-05-28 | 深圳市长昊机电有限公司 | Grid-connected photovoltaic power generation system and control method thereof |
| CN203933039U (en) * | 2014-03-03 | 2014-11-05 | 苏州大学 | A kind of photovoltaic combining inverter |
| CN203839977U (en) * | 2014-05-08 | 2014-09-17 | 上海理工大学 | Photovoltaic inverting device |
| CN104765012A (en) * | 2015-04-21 | 2015-07-08 | 阳光电源股份有限公司 | Fault detection method, fault detection circuit and inverter |
| CN104810858A (en) * | 2015-05-27 | 2015-07-29 | 广西大学 | Control method for grid-connected power generation system of optical storage microgrid |
| CN105356513A (en) * | 2015-12-14 | 2016-02-24 | 阳光电源股份有限公司 | Inverter wiring error self-adaption method as well as device and application of method and photovoltaic system |
| CN105871324A (en) * | 2016-04-11 | 2016-08-17 | 厦门科华恒盛股份有限公司 | Independent MPPT tracking method for multi-branch input photovoltaic inverter system |
| CN106452137A (en) * | 2016-07-12 | 2017-02-22 | 江苏兆伏爱索新能源有限公司 | Control method of improving conversion efficiency of multiple maximum power point tracking (MPPT) inverters |
| US20180109136A1 (en) * | 2016-10-13 | 2018-04-19 | Schneider Electric It Corporation | Dc-link bus balancer |
| CN107807305A (en) * | 2017-10-30 | 2018-03-16 | 阳光电源股份有限公司 | A kind of assembly type inverter Wiring detection method, apparatus and system |
| CN107843806A (en) * | 2017-10-30 | 2018-03-27 | 阳光电源股份有限公司 | A kind of Wiring detection method, device and photovoltaic generating system |
| CN109510450A (en) * | 2018-12-27 | 2019-03-22 | 阳光电源股份有限公司 | A kind of reverse connecting protection method and photovoltaic generating system |
| CN110391676A (en) * | 2019-08-09 | 2019-10-29 | 阳光电源股份有限公司 | A kind of multichannel MPPT inverter and its control method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110880741B (en) | 2022-02-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107408835B (en) | Uninterruptible power supply device and uninterruptible power supply system using same | |
| US11070124B2 (en) | Power conversion device | |
| JP6730515B2 (en) | Power converter | |
| US10084393B2 (en) | Cascade converter system and method of putting converter module of the same into operation | |
| CA2991877C (en) | Uninterruptible power supply | |
| CN110048626B (en) | Inverter alternating current closing common-mode impact current suppression method and application device thereof | |
| CN109301813B (en) | Fault control method, controller and medium-high voltage energy conversion system | |
| CN112803485B (en) | Photovoltaic rapid turn-off system and control method thereof | |
| EP3694098A1 (en) | Power conversion apparatus | |
| US10122261B2 (en) | Power conversion device | |
| US11644506B2 (en) | Power switch fault detection method and power switch fault detection circuit | |
| US11736001B2 (en) | Method for capacitor discharging for an inverter assembly | |
| CN113098273A (en) | Multi-input Boost circuit and fault detection method thereof | |
| EP3944451A1 (en) | Photovoltaic inverter, photovoltaic system, and method for controlling discharging | |
| CN103944420A (en) | Power supply system and control method thereof | |
| CN110880741B (en) | Inversion system and input misconnection detection method of symmetrical three-level booster circuit of inversion system | |
| CN113922652B (en) | Inverter, inverter system, lightning protection circuit and control method of lightning protection circuit | |
| JP2019054641A (en) | Power conversion equipment | |
| KR20150005822A (en) | Apparatus and method of controlling instant power failure of h-bridge multi-level inverter | |
| CN110308341B (en) | Inversion module detection method, device and system in energy conversion system | |
| CN212086073U (en) | Feedback device with float function of filling | |
| JP2013106393A (en) | Instantaneous voltage drop compensation device | |
| CN113824163B (en) | Energy router and control method thereof | |
| CN112821866B (en) | Photovoltaic rapid turn-off system and control method thereof | |
| CN116937692A (en) | Inverter alternating-current side discharge control method and inverter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |