CN113109624A - Insulation impedance detection method, converter and energy storage conversion system - Google Patents
Insulation impedance detection method, converter and energy storage conversion system Download PDFInfo
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- CN113109624A CN113109624A CN202110371938.4A CN202110371938A CN113109624A CN 113109624 A CN113109624 A CN 113109624A CN 202110371938 A CN202110371938 A CN 202110371938A CN 113109624 A CN113109624 A CN 113109624A
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Abstract
The application provides an insulation impedance detection method, a converter and an energy storage conversion system, wherein the converter comprises a plurality of pairs of connection ports on a side of a system to be detected, and each connection port is collected to a direct current bus provided with an insulation impedance detection circuit through a corresponding transmission branch circuit in the converter; the insulation impedance detection method controls each pair of transmission branch circuits to be conducted one by one; when each pair of transmission branches is in a conducting state, the insulation impedance detection circuit is multiplexed to realize the insulation impedance detection of the direct current power supply connected with the corresponding pair of connection ports; when multiple batteries are connected in parallel through the converter in the energy storage system, the insulation impedance detection of the batteries can be realized one by one through the one-by-one conduction of each pair of transmission branches and the multiplexing of the insulation impedance detection circuit, and the corresponding insulation impedance detection circuit does not need to be added for each battery, so that the increase of corresponding cost is avoided.
Description
Technical Field
The invention relates to the technical field of insulation detection, in particular to an insulation impedance detection method, a converter and an energy storage conversion system.
Background
In the energy storage conversion system, the main function of the converter is to perform charge and discharge management on the battery in the energy storage system, and before the converter works, the battery side of the converter is firstly ensured to meet the requirement on the ground impedance. At present, a converter mainly adopts a single-switch Y-type unbalanced bridge insulation impedance detection circuit to detect the insulation impedance of an energy storage system.
As shown in fig. 1, an existing single-switch Y-type unbalanced bridge insulation impedance detection circuit mainly includes: a switch S and a Y-shaped bridge arm consisting of R1, R2 and R3; one end of the Y-shaped bridge arm is connected with the anode BAT + of the corresponding battery in the energy storage system, the other end of the Y-shaped bridge arm is connected with the cathode BAT-of the battery, the third end of the Y-shaped bridge arm is grounded PE (Protecting earth), and the switch S is arranged between the midpoint of the Y-shaped bridge arm and the cathode BAT-of the battery. Wherein Rm and Rn are equivalent impedances to the ground of other partial circuits of the converter.
When single-machine insulation impedance detection is carried out, the switch S is controlled, and the BAT + resistance value R + of the PE and the BAT-resistance value R-of the PE are respectively calculated, so that whether the insulation impedance requirements are met or not is judged. However, the scheme is only effective for detecting a single-path battery, when multiple paths of batteries are connected in parallel to the converter in the energy storage system, because the voltages of the batteries are not necessarily the same, if the batteries are switched in simultaneously, voltage difference is generated to cause ignition; if a corresponding insulation resistance detection circuit is added to each battery, the cost of the detection circuit is increased.
Disclosure of Invention
Based on the defects of the prior art, the invention provides an insulation impedance detection method, a converter and an energy storage conversion system, so as to realize insulation impedance detection of multiple paths of parallel batteries on the basis of not increasing insulation detection cost.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the first aspect of the application discloses an insulation impedance detection method, which is applied to a converter, wherein a detected system side of the converter comprises a plurality of pairs of connection ports, and each connection port is gathered to a direct current bus provided with an insulation impedance detection circuit through a corresponding transmission branch circuit in the converter; the insulation resistance detection method comprises the following steps:
controlling each pair of transmission branches to be conducted one by one;
and when each pair of transmission branches is in a conducting state, the insulation impedance detection circuit is multiplexed to realize the insulation impedance detection of the direct current power supply connected with the corresponding pair of connection ports.
Preferably, each of the transmission branches is a positive transmission branch or a negative transmission branch; if all the connection ports connected with the negative electrodes of the corresponding direct current power supplies share the same negative electrode transmission branch, controlling the conduction of each pair of the transmission branches one by one, comprising the following steps:
and controlling the conduction of the negative electrode transmission branch circuits, and controlling the conduction of other positive electrode transmission branch circuits one by one.
Preferably, if the insulation impedance detection circuit is a single-switch Y-type unbalanced bridge insulation impedance detection circuit, multiplexing the insulation impedance detection circuit to realize insulation impedance detection of the dc power supplies connected to the corresponding pair of connection ports includes:
controlling the switching action in the single-switch Y-type unbalanced bridge insulation impedance detection circuit;
obtaining voltage detection results before and after the switching action;
and calculating the insulation impedance of the corresponding direct current power supply according to the voltage detection result.
A second aspect of the present application discloses a converter comprising: the device comprises a main circuit, an insulation impedance detection circuit, a detection module and a control module; wherein:
two sides of the main circuit are respectively used as a tested system side and an external side of the converter;
the tested system side comprises a plurality of pairs of connecting ports, and each connecting port is collected to a direct current bus of the main circuit through a corresponding transmission branch in the main circuit;
the insulation impedance detection circuit is arranged on the direct current bus;
the detection module is used for detecting the current/voltage of the insulation resistance detection circuit and the current/voltage of the corresponding position in the main circuit and outputting the detection result to the control module;
the insulation impedance detection circuit and the main circuit are controlled by the control module;
the control module executes a program including the insulation resistance detection method as described in any of the above paragraphs of the first aspect.
Preferably, each of the transmission branches is a positive transmission branch or a negative transmission branch;
each connecting port connected with the positive electrode of the corresponding direct-current power supply is respectively provided with a respective positive electrode transmission branch;
and all the connecting ports connected with the cathodes of the corresponding direct current power supplies share the same cathode transmission branch.
Preferably, each of the transmission branches is a positive transmission branch or a negative transmission branch;
each of the connection ports is equipped with a respective transmission branch.
Preferably, the transmission branch comprises: the fuse wire, the first contactor and the slow starting branch circuit are arranged on the shell; wherein:
one end of the fuse is connected with the corresponding connecting port, and the other end of the fuse is connected with the corresponding pole of the direct current bus through the first contactor;
the slow starting branch is connected with the first contactor in parallel;
the slow starting branch and the first contactor are controlled by the control module.
Preferably, the method further comprises the following steps: and the second contactor is used for getting power from a connecting point between the fuse wire and the first contactor in any positive electrode transmission branch circuit and supplying power for the control module.
Preferably, the insulation resistance detection circuit is a single-switch Y-type unbalanced bridge insulation resistance detection circuit.
Preferably, the main circuit includes: the power conversion circuit, the bus capacitor module, the filtering module, the direct current bus and each transmission branch circuit;
one side of each transmission branch is connected with the corresponding connecting port, and the other side of each transmission branch is connected to the direct current bus;
the direct current bus is connected with the bus capacitor module through the filter module;
the bus capacitor module is connected with the outer sides of the converter through the power conversion circuit;
the power conversion circuit and each transmission branch circuit are controlled by the control module.
Preferably, the power conversion circuit is: an inverter circuit, or alternatively, a DCDC conversion circuit.
Preferably, the power conversion circuit includes: a DCDC conversion circuit and an inverter circuit;
one side of the DCDC conversion circuit is connected with the filtering module;
the other side of the DCDC conversion circuit is connected with the direct current side of the inverter circuit through the bus capacitor module;
the alternating current side of the inverter circuit is used as the pair of outer sides.
Preferably, the filtering module is an LC filter.
Preferably, the direct current power supply is a battery or a photovoltaic string.
The third aspect of the present application discloses an energy storage conversion system, which is characterized by comprising: a plurality of batteries, and a converter as described in any of the paragraphs above with respect to the second aspect;
each battery is used as a corresponding direct current power supply and is respectively connected with a corresponding pair of connecting ports of the converter.
Based on the insulation impedance detection method provided by the application, the applied converter comprises a plurality of pairs of connection ports on the side of a system to be detected, and each connection port is collected to a direct current bus provided with an insulation impedance detection circuit through a corresponding transmission branch in the converter; the insulation impedance detection method controls each pair of transmission branch circuits to be conducted one by one; when each pair of transmission branches is in a conducting state, the insulation impedance detection circuit is multiplexed to realize the insulation impedance detection of the direct current power supply connected with the corresponding pair of connection ports; when multiple batteries are connected in parallel through the converter in the energy storage system, the insulation impedance detection of the batteries can be realized one by one through the one-by-one conduction of each pair of transmission branches and the multiplexing of the insulation impedance detection circuit, and the corresponding insulation impedance detection circuit does not need to be added for each battery, so that the increase of corresponding cost is avoided.
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 embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a conventional single-switch Y-type unbalanced bridge insulation resistance detection circuit;
FIG. 2 is a schematic diagram of a partial structure of a transducer according to an embodiment of the present disclosure;
fig. 3 is a flowchart of an insulation resistance detection method according to an embodiment of the present application;
FIG. 4 is a partial flowchart of an insulation resistance detection method according to an embodiment of the present application;
FIG. 5 is another schematic diagram of a transducer portion structure according to an embodiment of the present disclosure;
FIG. 6 is a schematic structural diagram of a converter provided in an embodiment of the present application;
fig. 7 is a topology diagram of a main circuit of a converter according to an embodiment of the present application;
fig. 8 is a schematic view of an application scenario of the transformer according to the embodiment of the present application.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the 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 invention provides an insulation resistance detection method, which is used for realizing insulation resistance detection of a plurality of paths of parallel batteries on the basis of not increasing insulation detection cost.
The insulation impedance detection method is applied to a converter, referring to fig. 2, the tested system side of the converter comprises a plurality of pairs of connection ports, as shown in fig. 2, wherein one pair of connection ports are respectively 1+ and 1-, and the other pair of connection ports are respectively N + and N-; each connection port is respectively gathered to a direct current bus provided with an insulation impedance detection circuit through a corresponding transmission branch (such as a transmission branch 1 to a transmission branch 4 shown in fig. 2) in the converter.
Referring to fig. 3, the insulation resistance detecting method includes:
and S101, controlling each pair of transmission branches to be conducted one by one.
And S102, multiplexing the insulation impedance detection circuit when each pair of transmission branches is in a conducting state respectively, and realizing insulation impedance detection of the direct current power supplies connected with the corresponding pair of connection ports.
In practical application, any pair of transmission branches can be controlled to be conducted, and then under the conducting state, the insulation impedance detection of the corresponding direct-current power supply is realized through the insulation impedance detection circuit; controlling the conduction of the other pair of transmission branches, and realizing the insulation impedance detection of the corresponding direct current power supply through the insulation impedance detection circuit again in the conduction state; and the insulation impedance detection of all the direct current power supplies is completed by multiplexing the insulation impedance detection circuit until all the transmission branches are conducted and passed.
Taking the structure shown in fig. 2 as an example, the transmission branches 1 and 2 connected to the ports 1+ and 1-may be controlled to be conducted first, and then the next pair of transmission branches may be controlled to be conducted until the transmission branches 3 and 4 are conducted; and the insulation impedance detection of each direct current power supply is realized by multiplexing the insulation impedance detection circuit when each pair of transmission branches are in a conducting state. In practical applications, the transmission branches may be controlled to be turned on one by one according to other sequences, which is only an example and is not limited thereto.
As can be seen from the above, the insulation resistance detection method provided in this embodiment can detect the insulation resistance of each dc power supply connected in parallel one by one. When the direct-current power supply is a battery, namely when multiple paths of batteries are connected in parallel in the energy storage system through the converter, if an insulation impedance detection circuit is added to each path of battery, the cost of the detection circuit is increased; the insulation impedance detection method provided by this embodiment respectively realizes insulation impedance detection for each path of battery through one-by-one conduction of each pair of transmission branches and multiplexing of the insulation impedance detection circuit, and does not need to add a corresponding insulation impedance detection circuit for each path of battery, thereby avoiding increase of corresponding cost.
In practical applications, each transmission branch is a positive transmission branch (e.g., transmission branch 1 and transmission branch 3 shown in fig. 2) or a negative transmission branch (e.g., transmission branch 2 and transmission branch 4 shown in fig. 2). There are two options for the arrangement of the transmission branches, one is as shown in fig. 2, each connection port is equipped with its own transmission branch; as shown in fig. 5, the connection ports (BAT1+ and BAT2+ in fig. 5) connected to the positive electrodes of the corresponding dc power supplies are respectively equipped with a positive electrode transmission branch, and the connection ports (BAT 1-and BAT2-) connected to the negative electrodes of the corresponding dc power supplies share the same negative electrode transmission branch, so that the transmission cost can be saved.
On the basis of the previous embodiment, for the structure shown in fig. 5, that is, when the connection ports connected to the negative electrodes of the corresponding dc power supplies share the same negative electrode transmission branch, the step S101 in the previous embodiment specifically includes: and controlling the conduction of the negative electrode transmission branch, and controlling the conduction of other positive electrode transmission branches one by one.
Fig. 5 shows an example in which the system side to be tested includes two pairs of connection ports (BAT1+ and BAT1-, and BAT2+ and BAT2-) and the dc power supply is a battery. When the first battery BAT1 needs to be detected, the positive transmission branch 1 and the negative transmission branch are controlled to be both switched on, and then the insulation impedance detection of the battery BAT1 is realized through an insulation impedance detection circuit; after the detection is completed, the positive transmission branch 1 is disconnected, the positive transmission branch 2 is connected, and the insulation impedance of the second battery BAT2 is detected through the insulation impedance detection circuit. In practical applications, each pair of transmission branches may also be controlled to be conducted one by one according to other sequences, which is only an example and is not limited thereto; moreover, the system side to be tested of the converter may also include more pairs of connection ports, and the principle is similar, and is not described herein again.
It should be noted that the insulation resistance detection circuit mentioned in the above embodiments may be any type of circuit in the prior art, such as the single-switch Y-type unbalanced bridge insulation resistance detection circuit shown in fig. 1; in practical application, a resistor and a switch connected in series may be respectively disposed between the positive electrode of the dc bus and the PE, and between the negative electrode of the dc bus and the PE. Without being limited thereto, any type of insulation resistance detection circuit in the prior art may be adopted, depending on the specific application environment, and all such circuits are within the protection scope of the present application.
Preferably, if the insulation resistance detection circuit is a single-switch Y-type unbalanced bridge insulation resistance detection circuit, on the basis of the foregoing embodiment, the multiplexing insulation resistance detection circuit in step S102 implements insulation resistance detection for the dc power supplies connected to the corresponding pair of connection ports, and specifically includes, as shown in fig. 4:
s201, controlling the switching action in the single-switch Y-type unbalanced bridge insulation impedance detection circuit.
S202, voltage detection results before and after switching action are obtained.
And S203, calculating the insulation impedance of the corresponding direct current power supply according to the voltage detection result.
Referring to the single-switch Y-type unbalanced bridge insulation impedance detection circuit shown in fig. 1, when each insulation impedance detection is performed, voltage detection results before and after the switch S is operated are obtained by controlling the on/off operation of the switch S, and the resistance value R + of the positive electrode BAT + to PE and the resistance value R-of the negative electrode BAT-to PE of the corresponding dc power supply are respectively calculated, so as to determine whether the dc power supply meets the requirement of insulation impedance.
If the insulation resistance detection circuit is in other forms in the prior art, the specific process of step S102 may refer to the corresponding prior art, and details are not repeated here.
Another embodiment of the present application further provides a converter, as shown in fig. 6, including: a main circuit 100, an insulation resistance detection circuit 200, a detection module (not shown in the figure) and a control module (not shown in the figure); wherein:
one side of the main circuit 100, which is the system side to be tested of the converter, is connected to each dc power supply; the other side of the main circuit 100, which is the opposite side of the converter, is connected to an external device, such as a grid-connected transformer.
The side of the system to be tested is provided with a plurality of pairs of connection ports (for example, two pairs of connection ports shown in fig. 6: 1+ and 1-, and N + and N-), and each connection port is respectively gathered to the dc bus 101 of the main circuit 100 through a corresponding transmission branch in the main circuit 100. As shown in fig. 6: the connection port 1+ is connected to the direct current bus 101 through the transmission branch 1, the connection port 1-is connected to the direct current bus 101 through the transmission branch 2, the connection port N + is connected to the direct current bus 101 through the transmission branch 3, and the connection port N-is connected to the direct current bus 101 through the transmission branch 4.
The insulation resistance detection circuit 200 is arranged on the direct current bus 101; the insulation resistance detection circuit 200 may be any type of circuit known in the art, and is preferably a single-switch Y-type unbalanced bridge insulation resistance detection circuit as shown in fig. 1; in practical applications, a resistor and a switch connected in series may be respectively disposed between the positive electrode of the dc bus 101 and the PE, and between the negative electrode of the dc bus 101 and the PE. Without being limited thereto, any type of insulation resistance detection circuit in the prior art may be adopted, depending on the specific application environment, and all such circuits are within the protection scope of the present application.
The detection module is configured to detect current/voltage at corresponding positions in the insulation resistance detection circuit 200 and the main circuit 100, for example, detect voltage before and after an operation of a switch S in the insulation resistance detection circuit 200, and generate a corresponding voltage detection result; then, the detection module outputs each detection result to the control module to assist the control module to realize various control functions.
The insulation resistance detection circuit 200 and the main circuit 100 are controlled by a control module; specifically, the on/off of the switch S in the insulation resistance detection circuit 200 is controlled by a control module, the on/off of each transmission branch in the main circuit 100 is controlled by the control module, and the output voltage/current of the main circuit 100 is also controlled by the control module.
The control module executes various programs to complete the control function, and the executed programs include the insulation resistance detection method according to any of the above embodiments, and other executed programs may refer to the prior art and are not described herein again.
The specific process and principle of the insulation resistance detection method can be found in the above embodiments, and are not described herein again.
On the basis of the above embodiment, it is preferable that each transmission branch is divided into two types, one is a positive transmission branch (transmission branch 1 and transmission branch 3 shown in fig. 6), and the other is a negative transmission branch (transmission branch 2 and transmission branch 4 shown in fig. 6).
There are two options for the arrangement of the transmission branches, one is as shown in fig. 2, each connection port is equipped with its own transmission branch; as shown in fig. 5 and 7, the connection ports (for example, BAT1+ and BAT2+ in fig. 5 and 7) for connecting the positive electrodes of the corresponding dc power supplies are respectively equipped with a respective positive transmission branch, and the connection ports (for example, BAT 1-and BAT2-) in fig. 5 and 7) for connecting the negative electrodes of the corresponding dc power supplies share the same negative transmission branch, so that the transmission cost can be saved.
Preferably, as shown in fig. 7, the transmission branch includes: fuses (FU 1, FU2, and FU3 as shown in fig. 7), first contactors (K2, K3, and K4 as shown in fig. 7), and soft-start branches (branches connected in parallel with K2, K3, and K4, respectively, as shown in fig. 7).
In each transmission branch, one end of the fuse is connected to the corresponding connection port, and the other end of the fuse is connected to the corresponding pole of the dc bus 101 through the first contactor. FIG. 7 shows an example in which the system side to be tested includes two pairs of connection ports (BAT1+ and BAT1-, and BAT2+ and BAT2-) and the DC power supply is a battery; specifically, in the first positive electrode transmission branch, the connection port BAT1+ is connected with one end of the fuse FU1, and the other end of the fuse FU1 is connected with the positive electrode of the direct current bus through the first contactor K2; in the second positive electrode transmission branch, a connection port BAT2+ is connected with one end of a fuse FU2, and the other end of the fuse FU2 is connected with the positive electrode of the direct-current bus through a first contactor K3; in the negative electrode transmission branch, connection ports BAT 1-and BAT 2-are both connected with one end of a fuse FU3, and the other end of the fuse FU3 is connected with the negative electrode of a direct current bus through a first contactor K4. In addition, the shut1 and the shut2 described in fig. 7 are detection devices in the detection module for detecting the current in the corresponding positive transmission branch, and the setting manner of the detection devices may refer to the prior art, which is not described herein again.
In each transmission branch, the slow starting branch is connected with the first contactor in parallel; as shown in fig. 7, the first contactors K2, K3 and K4 are respectively connected in parallel with corresponding slow-start branches for implementing a slow-start function when the converter is put into a normal operation state.
In practical application, the on and off of each slow starting branch and the pull-in and off of the first contactor are controlled by the control module.
For the structure shown in fig. 7, when the first battery BAT1 needs to be detected, the contactors K2 and K4 are pulled in, and then the insulation resistance detection for the battery BAT1 is realized through the insulation resistance detection circuit; after the detection is finished, the contactor K2 is disconnected, the contactor K3 is closed, and the insulation impedance of the second battery BAT2 is detected through an insulation impedance detection circuit.
Preferably, the converter further comprises: and the second contactor is used for getting power from a connecting point between the fuse wire and the first contactor in any positive electrode transmission branch circuit and supplying power for the control module.
In fig. 7, taking the second contactor K1 as an example to take power from the connection point between the fuse FU1 and the first contactor K2 in the first positive transmission branch as an example, in practical applications, the second contactor may take power from any positive transmission branch, which is not limited herein and is within the protection scope of the present application.
In addition, in practical application, the second contactor can be controlled by the MCU which is externally powered and is arranged in the converter, so that the converter can supply power to the control module in the starting stage.
On the basis of the above embodiment, it is preferable that, as shown in fig. 6, the main circuit 100 includes: power conversion circuit 104, bus capacitor module 103, filter module 102, dc bus 101, and various transmission branches (transmission branch 1 to transmission branch 4 shown in fig. 6).
Specifically, one side of each transmission branch is connected with a corresponding connection port, and the other side of each transmission branch is connected to the dc bus 101; the direct current bus 101 is connected with a bus capacitor module 103 through a filter module 102; the bus capacitor module 103 is connected with the outer side of the converter through a power conversion circuit 104; the power conversion circuit 104 and each transmission branch are controlled by a control module.
In practical applications, the filtering module 102 is preferably an LC filter, such as the common mode inductor and the capacitor C shown in fig. 7; however, the present invention is not limited thereto, and other filtering structures may be adopted, and are within the scope of the present application. Additionally, the bus capacitor module 103 may include two series capacitors C1 and C2 as shown in fig. 7 to achieve voltage support for the dc bus 101 while providing a dc side midpoint for the subsequent power conversion modules 104.
For different converters, the topology of the power conversion circuit 104 is different, for example, when the power conversion circuit 104 is an inverter circuit, the converter is a photovoltaic inverter or an energy storage converter (a main circuit of which is shown in fig. 7), and an external side of the photovoltaic inverter or the energy storage converter is used for connecting to a power grid; alternatively, the power conversion circuit 104 may also be a DCDC conversion circuit, for example, the converter is an energy storage DC conversion device, as shown in fig. 8, and the system side to be tested is connected to the energy storage system, and the external sides of the energy storage system are respectively connected to the DC-DC of the front stage and the DC-AC of the rear stage in the photovoltaic inverter.
In addition, when the converter is a photovoltaic inverter or an energy storage converter, the power conversion circuit 104 may further include a DCDC conversion circuit, that is, the power conversion circuit 104 may include: a DCDC conversion circuit and an inverter circuit; one side of the DCDC conversion circuit is connected with the filtering module 102; the other side of the DCDC conversion circuit is connected with the direct current side of the inverter circuit through a bus capacitor module 103; the AC side of the inverter circuit is used as the opposite side.
In practical application, each direct current power supply connected to the tested system side of the converter can be a battery or a photovoltaic string; when the battery is used, the power conversion circuit 104 is required to have a bidirectional power conversion function.
Another embodiment of the present application further provides an energy storage conversion system, including: a plurality of batteries, and an inverter as described in any of the above embodiments;
each battery is used as a corresponding direct current power supply and is respectively connected with a corresponding pair of connecting ports of the converter.
The structure and the operation principle of the converter can be obtained by referring to the above embodiments, and are not described in detail herein.
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.
In the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other to enable those skilled in the art to make or use the 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 (15)
1. The insulation impedance detection method is characterized by being applied to a converter, wherein the side of a system to be detected of the converter comprises a plurality of pairs of connection ports, and each connection port is collected to a direct current bus provided with an insulation impedance detection circuit through a corresponding transmission branch in the converter; the insulation resistance detection method comprises the following steps:
controlling each pair of transmission branches to be conducted one by one;
and when each pair of transmission branches is in a conducting state, the insulation impedance detection circuit is multiplexed to realize the insulation impedance detection of the direct current power supply connected with the corresponding pair of connection ports.
2. The insulation resistance detection method according to claim 1, wherein each of the transmission branches is a positive transmission branch or a negative transmission branch; if all the connection ports connected with the negative electrodes of the corresponding direct current power supplies share the same negative electrode transmission branch, controlling the conduction of each pair of the transmission branches one by one, comprising the following steps:
and controlling the conduction of the negative electrode transmission branch circuits, and controlling the conduction of other positive electrode transmission branch circuits one by one.
3. The insulation resistance detection method according to claim 1, wherein if the insulation resistance detection circuit is a single-switch Y-type unbalanced bridge insulation resistance detection circuit, multiplexing the insulation resistance detection circuit to detect the insulation resistance of the dc power supply connected to the corresponding pair of connection ports comprises:
controlling the switching action in the single-switch Y-type unbalanced bridge insulation impedance detection circuit;
obtaining voltage detection results before and after the switching action;
and calculating the insulation impedance of the corresponding direct current power supply according to the voltage detection result.
4. A transducer, comprising: the device comprises a main circuit, an insulation impedance detection circuit, a detection module and a control module; wherein:
two sides of the main circuit are respectively used as a tested system side and an external side of the converter;
the tested system side comprises a plurality of pairs of connecting ports, and each connecting port is collected to a direct current bus of the main circuit through a corresponding transmission branch in the main circuit;
the insulation impedance detection circuit is arranged on the direct current bus;
the detection module is used for detecting the current/voltage of the insulation resistance detection circuit and the current/voltage of the corresponding position in the main circuit and outputting the detection result to the control module;
the insulation impedance detection circuit and the main circuit are controlled by the control module;
the control module executes a program including the insulation resistance detection method according to any one of claims 1 to 3.
5. The converter according to claim 4, wherein each of the transmission branches is a positive transmission branch or a negative transmission branch;
each connecting port connected with the positive electrode of the corresponding direct-current power supply is respectively provided with a respective positive electrode transmission branch;
and all the connecting ports connected with the cathodes of the corresponding direct current power supplies share the same cathode transmission branch.
6. The converter according to claim 4, wherein each of the transmission branches is a positive transmission branch or a negative transmission branch;
each of the connection ports is equipped with a respective transmission branch.
7. The converter according to claim 5, characterized in that said transmission branch comprises: the fuse wire, the first contactor and the slow starting branch circuit are arranged on the shell; wherein:
one end of the fuse is connected with the corresponding connecting port, and the other end of the fuse is connected with the corresponding pole of the direct current bus through the first contactor;
the slow starting branch is connected with the first contactor in parallel;
the slow starting branch and the first contactor are controlled by the control module.
8. The converter of claim 7, further comprising: and the second contactor is used for getting power from a connecting point between the fuse wire and the first contactor in any positive electrode transmission branch circuit and supplying power for the control module.
9. The converter of claim 4, wherein said insulation resistance detection circuit is a single switch Y-unbalanced bridge insulation resistance detection circuit.
10. A converter according to any of claims 4-9, characterized in that the main circuit comprises: the power conversion circuit, the bus capacitor module, the filtering module, the direct current bus and each transmission branch circuit;
one side of each transmission branch is connected with the corresponding connecting port, and the other side of each transmission branch is connected to the direct current bus;
the direct current bus is connected with the bus capacitor module through the filter module;
the bus capacitor module is connected with the outer sides of the converter through the power conversion circuit;
the power conversion circuit and each transmission branch circuit are controlled by the control module.
11. The converter of claim 10, wherein the power conversion circuit is: an inverter circuit, or alternatively, a DCDC conversion circuit.
12. The converter of claim 10, wherein the power conversion circuit comprises: a DCDC conversion circuit and an inverter circuit;
one side of the DCDC conversion circuit is connected with the filtering module;
the other side of the DCDC conversion circuit is connected with the direct current side of the inverter circuit through the bus capacitor module;
the alternating current side of the inverter circuit is used as the pair of outer sides.
13. The converter according to claim 10, wherein said filtering module is an LC filter.
14. A converter according to any of claims 4 to 9, wherein the dc power source is a battery or a string of photovoltaic cells.
15. An energy storage conversion system, comprising: a plurality of batteries, and a converter according to any one of claims 4-14;
each battery is used as a corresponding direct current power supply and is respectively connected with a corresponding pair of connecting ports of the converter.
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| CN202110371938.4A CN113109624A (en) | 2021-04-07 | 2021-04-07 | Insulation impedance detection method, converter and energy storage conversion system |
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| CN202110371938.4A CN113109624A (en) | 2021-04-07 | 2021-04-07 | Insulation impedance detection method, converter and energy storage conversion system |
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| CN211905521U (en) * | 2020-01-16 | 2020-11-10 | 阳光电源股份有限公司 | Insulation impedance detection circuit and application device thereof |
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Application publication date: 20210713 |