Insulation resistance detection method of parallel operation system and parallel operation system
By performing the number management of the inverter and triggering insulation impedance detection in the parallel system in the parallel system, the problem of inverter detection in the parallel system is solved, and accurate insulation impedance detection is achieved.
Patent Information
- Application Number
- CN202411352888.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-02-07
AI Technical Summary
In a parallel system, when multiple inverters are connected in parallel, the inverter is prone to deviations and errors when performing insulation impedance detection, resulting in inaccurate detection.
By controlling the parallel control board, multiple inverters are assigned numbers and controlling the inverter based on the number to trigger insulation impedance detection with a preset delay time-division time, ensuring that only one inverter is used for detection at the same time, avoiding relays The situation of simultaneous absorption and integration.
It effectively avoids the situation where multiple inverter relays are attracted and connected at the same time, ensuring that the inverter detects accurate insulation impedance and avoids detection errors.
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Figure CN119395376A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the technical field of parallel control, and in particular to an insulation impedance detection method for a parallel system and a parallel system. Background Art
[0002] In existing parallel systems, an inverter is often used to detect the insulation impedance of the power supply, and whether the power supply is normal is determined based on the detected insulation impedance; when the insulation impedance is high enough, the power supply does not form a conductive loop with the ground, and the power supply is insulated from the ground; when the insulation impedance is too low, the power supply forms a leakage loop with the ground, which is easy to cause a short circuit. The power supply can be a photovoltaic panel or a battery pack, etc.
[0003] When the inverter is testing the insulation impedance, the voltage corresponding to the insulation impedance is detected by closing or disconnecting the relay in the inverter to obtain the insulation impedance of the power supply. In a parallel system, multiple inverters are connected in parallel, and the ground terminal of each inverter is short-circuited with the neutral line (N line) of the busbar; at this time, the insulation impedance detected by the inverter is prone to deviation, resulting in detection errors. Summary of the invention
[0004] The embodiments of the present application provide a method for detecting insulation impedance of a parallel system and a parallel system, which can enable an inverter to detect accurate insulation impedance and avoid detection errors.
[0005] The embodiment of the present application provides an insulation impedance detection method for a parallel system, wherein the parallel system comprises: a plurality of power supplies, a plurality of inverters, and a parallel control board; wherein the plurality of inverters communicate with the parallel control board in parallel, each of the inverters is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply;
[0006] The insulation impedance detection method includes: controlling the parallel control board to assign corresponding numbers to the multiple inverters, and controlling the multiple inverters to trigger insulation impedance detection in time-sharing with a preset delay time based on the numbers of the multiple inverters; wherein the preset delay time is greater than or equal to the time for the inverter to complete the insulation impedance detection.
[0007] Furthermore, the controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters includes:
[0008] Controlling the parallel control board, sending the serial numbers of the plurality of inverters to the corresponding inverters, and synchronously sending insulation impedance detection instructions to the plurality of inverters;
[0009] The inverter is controlled to determine the target delay time of the inverter based on the inverter number and the preset delay time after receiving the insulation impedance detection instruction, and the insulation impedance detection is triggered when the target delay time is reached.
[0010] Further, the determining a target delay duration of the inverter based on the number of the inverter and the preset delay duration includes:
[0011] The target delay time of the inverter is obtained by subtracting one from the serial number of the inverter and then multiplying the result by the preset delay time.
[0012] Furthermore, the controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters includes:
[0013] Control the parallel control board, determine the target delay time of the multiple inverters based on the numbers of the multiple inverters and the preset delay time, and send an insulation impedance detection instruction to the corresponding inverter when the target delay time is reached, so that the corresponding inverter triggers insulation impedance detection.
[0014] Furthermore, the controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters includes:
[0015] Control the parallel control board, send an insulation impedance detection command to the inverter with the current number, drive the inverter with the current number to trigger the insulation impedance detection, and after the preset delay time, send an insulation impedance detection command to the inverter with the next number corresponding to the current number, and repeat until the insulation impedance detection command is sent to multiple inverters; wherein the inverter with the current number is any inverter among the multiple inverters, and the inverter with the next number is the next inverter corresponding to the cyclic direction from small to large numbers.
[0016] Further, the inverter includes a first bridge arm formed by a first resistor and a second resistor, and a second bridge arm formed by a third resistor and a fourth resistor;
[0017] The bus positive electrode of the first bridge arm is connected to the bus positive electrode of the second bridge arm through a first relay, the bus negative electrode of the first bridge arm is connected to the bus negative electrode of the second bridge arm through a second relay, and the midpoint of the first bridge arm and the midpoint of the second bridge arm are both grounded;
[0018] A first insulation impedance between the positive electrode of the power supply and the ground is connected in parallel with the third resistor, and a second insulation impedance between the negative electrode of the power supply and the ground is connected in parallel with the fourth resistor.
[0019] Further, when the inverter triggers insulation impedance detection, the first relay and the second relay are controlled to be disconnected, and a first bus voltage between the positive pole of the bus and the negative pole of the bus and a first insulation voltage of the second insulation impedance are detected;
[0020] If the first insulation voltage is less than half of the first bus voltage, the first relay is controlled to be closed and the second relay is controlled to be disconnected, and the second bus voltage between the positive pole of the bus and the negative pole of the bus and the second insulation voltage of the second insulation impedance are detected;
[0021] If the first insulation voltage is greater than or equal to half of the first bus voltage, the first relay is controlled to be disconnected and the second relay is controlled to be closed, and a third bus voltage between the positive pole of the bus and the negative pole of the bus and a third insulation voltage of the second insulation impedance are detected;
[0022] The resistance values of the first insulation impedance and the second insulation impedance are determined based on the first bus voltage, the first insulation voltage, the second bus voltage, and the second insulation voltage; or the resistance values of the first insulation impedance and the second insulation impedance are determined based on the first bus voltage, the first insulation voltage, the third bus voltage, and the third insulation voltage.
[0023] Further, the inverter is controlled to take a minimum value between the first insulation impedance and the second insulation impedance, and the minimum value is compared with the insulation protection value; if the minimum value is less than the insulation protection value, insulation impedance abnormality information is reported to the parallel control board.
[0024] Furthermore, the parallel system further comprises: an insulation impedance tool;
[0025] The insulation impedance tool is connected in parallel with the first insulation impedance, and the impedance value of the first insulation impedance detected is compared with the impedance value of the insulation impedance tool, and whether the insulation impedance detection is accurate is determined based on the comparison result;
[0026] Alternatively, the insulation impedance tool is connected in parallel with the second insulation impedance, and the impedance value of the second insulation impedance detected is compared with the impedance value of the insulation impedance tool, and whether the insulation impedance detection is accurate is determined based on the comparison result.
[0027] An embodiment of the present application also provides a parallel system, which includes: multiple power supplies, multiple inverters and a parallel control board; wherein the multiple inverters communicate in parallel with the parallel control board, each inverter is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply; the parallel system adopts the above-mentioned insulation impedance detection method to perform insulation impedance detection.
[0028] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:
[0029] In an embodiment of the present application, a parallel system includes: multiple power supplies, multiple inverters and a parallel control board; wherein, multiple inverters communicate in parallel with the parallel control board, each inverter is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply; the insulation impedance detection method of the parallel system is: controlling the parallel control board to assign corresponding numbers to multiple inverters, and based on the numbers of the multiple inverters, controlling the multiple inverters to trigger insulation impedance detection in a time-sharing manner with a preset delay time; wherein the preset delay time is greater than or equal to the time for the inverter to complete the insulation impedance detection.
[0030] By controlling multiple inverters to trigger the insulation impedance test in a time-sharing manner with a preset delay length, only one inverter performs insulation impedance test at the same time, which can effectively avoid the situation where the relays of multiple inverters are energized at the same time, and enable the inverter to detect accurate insulation impedance to avoid detection errors. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.
[0032] Figure 1 A schematic diagram of the structure of a parallel system disclosed in an embodiment of the present application;
[0033] Figure 2 This is a flow chart of insulation impedance detection of a parallel system disclosed in an embodiment of the present application;
[0034] Figure 3 A circuit diagram of insulation impedance detection disclosed in an embodiment of the present application;
[0035] Figure 4 A circuit diagram of another insulation impedance detection disclosed in an embodiment of the present application;
[0036] Figure 5 A circuit diagram for performing insulation impedance detection on multiple inverters disclosed in an embodiment of the present application. DETAILED DESCRIPTION
[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0038] In the description of the embodiments of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the embodiments of the present application.
[0039] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.
[0040] In existing parallel systems, inverters are often used to perform insulation impedance detection on power supplies. When performing insulation impedance detection, the inverter detects the voltage corresponding to the insulation impedance by closing or disconnecting the relay in the inverter to obtain the insulation impedance of the power supply. In a parallel system, multiple inverters are connected in parallel, and the ground terminal of each inverter is short-circuited with the neutral line (N line) of the bus. When multiple inverters perform insulation detection at the same time in a parallel system, the relays of multiple inverters may be closed at the same time; when the relays of multiple inverters are closed at the same time, the insulation impedance detection resistor of one inverter will be coupled to other inverters through the parallel circuit, which will cause the impedance value detected by the inverter to be too small and cause detection errors. If the small value is lower than the set insulation impedance detection threshold, the parallel system will be unable to start up. Therefore, an embodiment of the present application provides an insulation impedance detection method for a parallel system, which enables the inverter to detect accurate insulation impedance and avoid detection errors, such as Figure 1 As shown, the details are as follows:
[0041] The parallel system of the embodiment of the present application includes: multiple power supplies 101, multiple inverters 102 and a parallel control board 103; wherein, the multiple inverters 102 communicate in parallel with the parallel control board 103. Specifically, the parallel control board 103 is provided with a communication interface, and the parallel control board 103 communicates in parallel with the multiple inverters 102 through the communication interface. The communication interface can be a CAN bus interface or a serial port interface, which is not specifically limited here; the parallel control board 103 can communicate in parallel with the multiple inverters 102 through the CAN bus, or through serial port communication (such as RS232), which is not specifically limited here.
[0042] The power source 101 can be a power generation device such as a photovoltaic panel or a battery pack, which is not limited here. Each inverter 102 is connected to at least one power source 101, and different inverters 102 are connected to different power sources 101, such as one inverter can be connected to multiple photovoltaic panels; the inverter 102 is used to detect the insulation impedance of the connected power source 101; for example, when the power source is a photovoltaic panel, the inverter can detect the insulation impedance of the photovoltaic positive pole to the ground and the insulation impedance of the photovoltaic negative pole to the ground.
[0043] The corresponding insulation impedance detection method of the parallel system is as follows: Figure 2 As shown, the following steps are included:
[0044] 201. The control board for parallel operation allocates corresponding numbers to multiple inverters.
[0045] In the embodiment of the present application, the parallel control board 103 can be controlled to assign corresponding numbers to multiple inverters 102; it can be understood that the parallel control board 103 can obtain the identification information of multiple inverters 102, and the identification information can be the factory serial number, model or standard code of the inverter, etc., which is not limited here. Among them, the number can be a serial number or an ID address, etc., such as the parallel control board can be controlled to assign corresponding serial numbers to multiple inverters based on the identification information of the inverter, or assign corresponding ID addresses to multiple inverters based on the identification information of the inverter.
[0046] 202. Based on the serial numbers of the multiple inverters, the multiple inverters are controlled to trigger insulation impedance detection in a time-sharing manner with a preset delay time.
[0047] After assigning corresponding numbers to the multiple inverters 102, the multiple inverters 102 can be controlled based on the numbers of the multiple inverters 102 to trigger the insulation impedance detection in a time-sharing manner with a preset delay time; wherein the preset delay time is greater than or equal to the time it takes for the inverter to complete the insulation impedance detection, such as the time it takes for the inverter to complete the insulation impedance detection is 12S, at this time, the preset delay time can be set to 13S or 15S, which is not limited here. The insulation impedance detection of the power supply can be performed after the inverter is turned on and before normal operation.
[0048] Based on the numbers of multiple inverters 102, the inverters can be controlled one by one to trigger insulation impedance detection. After a certain inverter is triggered to perform insulation impedance detection, the next inverter is triggered to perform insulation impedance detection after waiting for a preset delay time (i.e., waiting for the inverter to complete insulation impedance detection); that is, multiple inverters trigger insulation impedance detection in time-sharing, and only one inverter performs insulation impedance detection at the same time, avoiding the impact of multiple inverters performing insulation impedance detection at the same time. Among them, the inverters can be triggered one by one from small to large numbers to perform insulation impedance detection, or the inverters can be triggered one by one from large to small numbers to perform insulation impedance detection.
[0049] It can be seen that in the embodiment of the present application, the parallel system includes: multiple power supplies, multiple inverters and a parallel control board; wherein, the multiple inverters communicate in parallel through the parallel control board, each inverter is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply; the insulation impedance detection method of the parallel system is: controlling the parallel control board to assign corresponding numbers to the multiple inverters, and based on the numbers of the multiple inverters, controlling the multiple inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time; wherein the preset delay time is greater than or equal to the time for the inverter to complete the insulation impedance detection.
[0050] By controlling multiple inverters to trigger the insulation impedance test in a time-sharing manner with a preset delay length, only one inverter performs insulation impedance test at the same time, which can effectively avoid the situation where the relays of multiple inverters are energized at the same time, and enable the inverter to detect accurate insulation impedance to avoid detection errors.
[0051] Furthermore, a solution for time-sharingly triggering insulation impedance detection is: controlling the parallel control board to send the numbers of multiple inverters to the corresponding inverters, and synchronously sending insulation impedance detection instructions to multiple inverters, that is, multiple inverters receive the insulation impedance detection instructions at the same time.
[0052] The control inverter determines the target delay time of the inverter based on the inverter number and the preset delay time after receiving the insulation impedance detection instruction, and triggers the insulation impedance detection at the moment of reaching the target delay time. Specifically, the inverter number can be subtracted by one and then multiplied by the preset delay time to obtain the target delay time of the inverter. If the preset delay time is 15S, the parallel system includes 3 inverters, and the corresponding numbers are 1, 2, and 3; then the target delay time of the inverter numbered 1 is 0S, that is, no delay, the target delay time of the inverter numbered 2 is 15S, and the target delay time of the inverter numbered 3 is 30S; when the three inverters synchronously receive the insulation impedance detection instruction, the inverter numbered 1 immediately triggers the insulation impedance detection, the inverter numbered 2 triggers the insulation impedance detection after a delay of 15S, and the inverter numbered 3 triggers the insulation impedance detection after a delay of 30S.
[0053] Further, another solution for time-sharing triggering of insulation impedance detection is: control the parallel control board, determine the target delay time of multiple inverters based on the numbers of multiple inverters and the preset delay time, and send an insulation impedance detection instruction to the corresponding inverter at the moment of reaching the target delay time, so that the corresponding inverter triggers insulation impedance detection. For example, if the target delay time of the inverter numbered 1 is 0S, that is, no delay, the target delay time of the inverter numbered 2 is 15S, and the target delay time of the inverter numbered 3 is 30S; then first send an insulation impedance detection instruction to the inverter numbered 1, and trigger the delay timing, the inverter numbered 1 triggers insulation impedance detection, and after the delay time reaches 15S, the insulation impedance detection instruction is sent to the inverter numbered 2, and after the delay time reaches 30S, the insulation impedance instruction is sent to the inverter numbered 3.
[0054] Furthermore, another scheme for time-sharing triggering of insulation impedance detection is: control the parallel control board, send an insulation impedance detection command to the inverter with the current number, drive the inverter with the current number to trigger insulation impedance detection, and send an insulation impedance detection command to the inverter with the next number corresponding to the current number after a preset delay time interval, repeat until the insulation impedance detection command is sent to multiple inverters; wherein, the inverter with the current number is any inverter among the multiple inverters, and the inverter with the next number is the next inverter corresponding to the circular direction of the number from small to large. If the parallel system contains inverters numbered 1, 2, 3, and 4, an insulation impedance detection instruction can be sent to the inverter numbered 3, then, an insulation impedance detection instruction is sent to the inverter numbered 4, then, an insulation impedance detection instruction is sent to the inverter numbered 1, and finally, an insulation impedance detection instruction is sent to the inverter numbered 2.
[0055] Furthermore, the circuit diagram of insulation impedance detection is as follows Figure 3 As shown, the inverter includes a first bridge arm formed by a first resistor R1 and a second resistor R2, and a second bridge arm formed by a third resistor R3 and a fourth resistor R4; the bus positive electrode BUS+ of the first bridge arm is connected to the bus positive electrode BUS+ of the second bridge arm through a first relay S1, and the bus negative electrode BUS- of the first bridge arm is connected to the bus negative electrode BUS- of the second bridge arm through a second relay S2, and the midpoint of the first bridge arm and the midpoint of the second bridge arm are both grounded GND; the first insulation impedance of the positive electrode of the power supply to the ground is connected in parallel with the third resistor R3, and the second insulation impedance of the negative electrode of the power supply to the ground is connected in parallel with the fourth resistor R4; if the power supply is a photovoltaic panel, the first insulation impedance Pos of the photovoltaic positive electrode PV+ to the ground is connected in parallel with the third resistor R3, and the second insulation impedance Neg of the photovoltaic negative electrode PV- to the ground is connected in parallel with the fourth resistor R4.
[0056] Among them, when the inverter triggers the insulation impedance detection, the first relay S1 and the second relay S2 are controlled to be disconnected, and the first bus voltage Ubus1 between the bus positive pole BUS+ and the bus negative pole BUS- and the first insulation voltage Upe1 of the second insulation impedance Neg are detected; if the first insulation voltage Upe1 is less than half of the first bus voltage Ubus1, the first relay S1 is controlled to be energized and the second relay S2 is disconnected, and the second bus voltage Ubus2 between the bus positive pole BUS+ and the bus negative pole BUS- and the second insulation voltage Upe2 of the second insulation impedance are detected; if the first insulation voltage Upe1 is greater than or equal to half of the first bus voltage Ubus1, then Control the first relay S1 to disconnect and the second relay S2 to attract, and detect the third bus voltage Ubus3 between the bus positive pole BUS+ and the bus negative pole BUS- and the third insulation voltage Upe3 of the second insulation impedance; determine the resistance values of the first insulation impedance Pos and the second insulation impedance Neg based on the first bus voltage Ubus1, the first insulation voltage Upe1, the second bus voltage Ubus2 and the second insulation voltage Upe2; or, determine the resistance values of the first insulation impedance Pos and the second insulation impedance Neg based on the first bus voltage Ubus1, the first insulation voltage Upe1, the third bus voltage Ubus3 and the third insulation voltage Upe3.
[0057] When the first relay S1 and the second relay S2 are disconnected, it can be obtained:
[0058]
[0059] When the first relay S1 is closed and the second relay S2 is disconnected, we can get:
[0060]
[0061] Dividing equation 1 by equation 2, we get:
[0062]
[0063] At this time, based on the first bus voltage Ubus1, the first insulation voltage Upe1, the second bus voltage Ubus2 and the second insulation voltage Upe2, the resistance values of the first insulation impedance Pos and the second insulation impedance Neg are determined as follows:
[0064]
[0065] in,
[0066] When the first relay S1 is disconnected and the second relay S2 is closed, we can get:
[0067]
[0068] Dividing equation 4 by equation 1, we get:
[0069]
[0070] At this time, based on the first bus voltage Ubus1, the first insulation voltage Upe1, the third bus voltage Ubus3 and the third insulation voltage Upe3, the resistance values of the first insulation impedance Pos and the second insulation impedance Neg are determined as follows:
[0071]
[0072] in,
[0073] It can be understood that in the embodiment of the present application, the resistance values of the first insulation impedance Pos and the second insulation impedance Neg can also be determined by detecting the insulation voltage of the first insulation impedance Pos, which is similar to the above-mentioned detection of the insulation voltage of the second insulation impedance Neg, and the details will not be repeated here.
[0074] After determining the resistance values of the first insulation impedance Pos and the second insulation impedance Neg, the inverter can be controlled to take the minimum value between the first insulation impedance Pos and the second insulation impedance Neg, and the minimum value is compared with the insulation protection value. If the minimum value is less than the insulation protection value, the insulation impedance abnormality is triggered, and the insulation impedance abnormality information is reported to the parallel control board. Among them, the insulation protection value can be the maximum output voltage of the power supply divided by 30mA.
[0075] Further, in the embodiment of the present application, after obtaining the resistance values of the first insulation impedance Pos and the second insulation impedance Neg, it is also possible to test whether the resistance values of the first insulation impedance Pos and the second insulation impedance Neg are accurate, as shown in the following example: Figure 4 As shown, the parallel system also includes: an insulation impedance tool Test, wherein the insulation impedance tool Test is connected in parallel with the first insulation impedance Pos, and the impedance value of the first insulation impedance Pos detected is compared with the impedance value of the insulation impedance tool Test, and whether the insulation impedance detection is accurate is determined based on the comparison result; that is, if the resistance value of the insulation impedance tool Test is close to that of the first insulation impedance Pos, it is determined that the first insulation impedance Pos detection is accurate, if not, it is determined that the first insulation impedance Pos detection is inaccurate; wherein, if the resistance value deviation between the insulation impedance tool Test and the insulation impedance is less than 5% or 8%, it can be determined that the resistance values are close, and the specific details are not limited here.
[0076] Alternatively, the insulation impedance fixture Test is connected in parallel with the second insulation impedance Neg, and the impedance value of the second insulation impedance Neg detected is compared with the impedance value of the insulation impedance fixture Test, and whether the insulation impedance detection is accurate is determined based on the comparison result. That is, if the insulation impedance fixture Test is close to the resistance value of the second insulation impedance Neg, it is determined that the first insulation impedance Pos detection is accurate, and if not, it is determined that the second insulation impedance Neg detection is inaccurate.
[0077] like Figure 5 As shown, the first inverter performs insulation impedance detection on the power source ESS1, and the second inverter performs insulation impedance detection on the power source ESS2, wherein the first inverter includes: resistor R1, resistor R2, resistor R3, resistor R4 and an inverter module, and the second inverter includes: resistor R5, resistor R6, resistor R7, resistor R8 and an inverter module; the inverter module of the first inverter is connected in parallel with the inverter output of the inverter module of the second inverter.
[0078] The embodiment of the present application also provides a parallel system, the parallel system comprising: a plurality of power supplies, a plurality of inverters and a parallel control board; wherein the plurality of inverters communicate with the parallel control board in parallel, each of the inverters is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply;
[0079] The parallel system adopts the above-mentioned insulation impedance detection method to perform insulation impedance detection.
[0080] The embodiment of the present application further provides a parallel device, which includes the above-mentioned parallel system.
[0081] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.
[0082] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.
[0083] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0084] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
[0085] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program code.
Claims
1. A method for detecting insulation impedance of a parallel system, characterized in that: The parallel system comprises: a plurality of power supplies, a plurality of inverters and a parallel control board; wherein the plurality of inverters communicate in parallel with the parallel control board, each inverter is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply; The insulation impedance detection method includes: controlling the parallel control board to assign corresponding numbers to the multiple inverters, and controlling the multiple inverters to trigger insulation impedance detection in time-sharing with a preset delay time based on the numbers of the multiple inverters; wherein the preset delay time is greater than or equal to the time for the inverter to complete the insulation impedance detection.
2. The insulation impedance detection method according to claim 1, characterized in that: The controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters comprises: Controlling the parallel control board, sending the serial numbers of the plurality of inverters to the corresponding inverters, and synchronously sending insulation impedance detection instructions to the plurality of inverters; The inverter is controlled to determine the target delay time of the inverter based on the inverter number and the preset delay time after receiving the insulation impedance detection instruction, and the insulation impedance detection is triggered when the target delay time is reached.
3. The insulation impedance detection method according to claim 2, characterized in that: The determining, based on the number of the inverter and the preset delay time, a target delay time of the inverter comprises: The target delay time of the inverter is obtained by subtracting one from the serial number of the inverter and then multiplying the result by the preset delay time.
4. The insulation impedance detection method according to claim 1, characterized in that: The controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters comprises: Control the parallel control board, determine the target delay time of the multiple inverters based on the numbers of the multiple inverters and the preset delay time, and send an insulation impedance detection instruction to the corresponding inverter when the target delay time is reached, so that the corresponding inverter triggers insulation impedance detection.
5. The insulation impedance detection method according to claim 1, characterized in that: The controlling of the plurality of inverters to trigger the insulation impedance detection in a time-sharing manner with a preset delay time based on the serial numbers of the plurality of inverters comprises: Control the parallel control board, send an insulation impedance detection command to the inverter with the current number, drive the inverter with the current number to trigger the insulation impedance detection, and after the preset delay time, send an insulation impedance detection command to the inverter with the next number corresponding to the current number, and repeat until the insulation impedance detection command is sent to multiple inverters; wherein the inverter with the current number is any inverter among the multiple inverters, and the inverter with the next number is the next inverter corresponding to the cyclic direction from small to large numbers.
6. The insulation impedance detection method according to claim 1, characterized in that: The inverter comprises a first bridge arm formed by a first resistor and a second resistor, and a second bridge arm formed by a third resistor and a fourth resistor; The bus positive electrode of the first bridge arm is connected to the bus positive electrode of the second bridge arm through a first relay, the bus negative electrode of the first bridge arm is connected to the bus negative electrode of the second bridge arm through a second relay, and the midpoint of the first bridge arm and the midpoint of the second bridge arm are both grounded; A first insulation impedance between the positive electrode of the power supply and the ground is connected in parallel with the third resistor, and a second insulation impedance between the negative electrode of the power supply and the ground is connected in parallel with the fourth resistor.
7. The insulation impedance detection method according to claim 6, characterized in that: When the inverter triggers insulation impedance detection, the first relay and the second relay are controlled to be disconnected, and a first bus voltage between the positive pole of the bus and the negative pole of the bus and a first insulation voltage of the second insulation impedance are detected; If the first insulation voltage is less than half of the first bus voltage, the first relay is controlled to be closed and the second relay is controlled to be disconnected, and the second bus voltage between the positive pole of the bus and the negative pole of the bus and the second insulation voltage of the second insulation impedance are detected; If the first insulation voltage is greater than or equal to half of the first bus voltage, the first relay is controlled to be disconnected and the second relay is controlled to be closed, and a third bus voltage between the positive pole of the bus and the negative pole of the bus and a third insulation voltage of the second insulation impedance are detected; The resistance values of the first insulation impedance and the second insulation impedance are determined based on the first bus voltage, the first insulation voltage, the second bus voltage, and the second insulation voltage; or the resistance values of the first insulation impedance and the second insulation impedance are determined based on the first bus voltage, the first insulation voltage, the third bus voltage, and the third insulation voltage.
8. The insulation impedance detection method according to claim 7, characterized in that: The inverter is controlled to take a minimum value between the first insulation impedance and the second insulation impedance, and the minimum value is compared with an insulation protection value; if the minimum value is less than the insulation protection value, insulation impedance abnormality information is reported to the parallel control board.
9. The insulation impedance detection method according to claim 6, characterized in that: The parallel system also includes: an insulation impedance tool; The insulation impedance tool is connected in parallel with the first insulation impedance, and the impedance value of the first insulation impedance detected is compared with the impedance value of the insulation impedance tool, and whether the insulation impedance detection is accurate is determined based on the comparison result; Alternatively, the insulation impedance tool is connected in parallel with the second insulation impedance, and the impedance value of the second insulation impedance detected is compared with the impedance value of the insulation impedance tool, and whether the insulation impedance detection is accurate is determined based on the comparison result.
10. A parallel system, characterized in that: The parallel system comprises: a plurality of power supplies, a plurality of inverters and a parallel control board; wherein the plurality of inverters communicate in parallel with the parallel control board, each inverter is connected to at least one power supply, and the inverter is used to detect the insulation impedance of the connected power supply; The parallel system adopts the insulation impedance detection method described in any one of claims 1 to 9 to perform insulation impedance detection.