Online detection method and device of contactor

Abstract

The invention discloses an online detection method and device for a contactor, and the method comprises the steps: transmitting a closing instruction to the contactor when the contactor is determined to work normally; determining the current closing time of the contactor according to the resistance change condition between the input end and the output end of the contactor; sending a disconnection instruction to the contactor; determining the current disconnection time of the contactor according to the resistance change condition between the input end and the output end of the contactor; and determining the current use frequency of the contactor according to the current closing time and the current opening time of the contactor and a preset corresponding relation. The current closing time and the current opening time of the contactor are detected on line, and then the corresponding current use frequency is determined according to the current closing time and the current opening time, so that the service life of the contactor is detected on line, and the contactor is replaced in time when the service life of the contactor reaches the upper limit. And safe and stable operation of a power supply loop where the contactor is located is ensured.

Description

Technical Field

[0001] This invention relates to the field of contactor technology, and in particular to an online detection method and apparatus for contactors. Background Technology

[0002] With the rapid development of new energy and DC products, the market demand and market share of DC contactors have increased accordingly. Contactors are usually used at the front end of power supply circuits to perform switching functions.

[0003] As the market share of contactors increases, their aging degree and service life are important indicators for evaluating their availability. In existing technologies, the service life of contactors is usually diagnosed during repairs after a failure, using methods such as X-ray inspection. It is not possible to effectively and quantitatively measure the lifespan of the contactor's elastic elements online in real time. Summary of the Invention

[0004] This invention provides an online detection method and apparatus for contactors, enabling real-time online detection of the contactor's service life.

[0005] According to one aspect of the present invention, an online detection method for a contactor is provided, comprising:

[0006] Once it is confirmed that the contactor is working properly, a closing command is sent to the contactor;

[0007] The current closing time of the contactor is determined based on the resistance change between the input and output terminals of the contactor.

[0008] Send a disconnect command to the contactor;

[0009] The current disconnection time of the contactor is determined based on the resistance change between the input and output terminals of the contactor.

[0010] The current number of times the contactor is used is determined based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the number of times each time parameter group is used. The time parameter groups include the closing time and opening time of the contactor.

[0011] Optionally, determining the current closing time of the contactor based on the resistance change between its input and output terminals includes:

[0012] The time difference between the moment the closing command is sent to the contactor and the moment when the resistance between the input and output terminals of the contactor changes to a first threshold value is taken as the current closing time of the contactor.

[0013] Optionally, determining the current disconnection time of the contactor based on the resistance change between the input and output terminals includes:

[0014] The time difference between the moment the disconnection command is sent to the contactor and the moment when the resistance between the input and output terminals of the contactor changes to a second threshold is taken as the current disconnection time of the contactor; the second threshold is greater than the first threshold.

[0015] Optionally, when it is determined that the number of times the contactor is used is less than the preset number of times it is used, the first threshold is set between 0.2mΩ and 0.35mΩ;

[0016] When it is determined that the number of times the contactor is used is greater than or equal to the preset number of times it is used, the first threshold is set between 0.45mΩ and 0.6mΩ.

[0017] Optionally, before sending a closing command to the contactor, the method further includes:

[0018] Send a closing command to the contactor;

[0019] Obtain the resistance value between the input and output terminals of the contactor, and use it as the first resistance value;

[0020] When the first resistance value of the contactor is less than or equal to the first threshold value, it is determined that the contactor is closed normally.

[0021] After a preset time interval, a disconnect command is sent to the contactor;

[0022] Obtain the resistance value between the input and output terminals of the contactor, and use it as the second resistance value;

[0023] When the second resistance value of the contactor is greater than the first threshold, it is determined that the contactor is normally disconnected.

[0024] When the contactor closes and opens normally, it is determined that the contactor is working properly.

[0025] Optionally, when the first resistance of the contactor is greater than the first threshold, the contactor is determined to be abnormally closed, and a first alarm signal is output.

[0026] Optionally, when the second resistance value of the contactor is less than or equal to the first threshold, the contactor is determined to be abnormally disconnected, and a second alarm signal is output.

[0027] Optionally, determining the current number of times the contactor is used based on its current closing time, current opening time, and a preset correspondence includes:

[0028] When a reference time parameter group exists among the multiple time parameter groups, the number of times the reference time parameter group is used is taken as the current number of times the contactor is used; the closing time in the reference time parameter group is equal to the current closing time of the contactor, and the opening time in the reference time parameter group is equal to the current opening time of the contactor;

[0029] If the reference time parameter group is not present in any of the multiple time parameter groups, the current number of times the contactor is used is determined by interpolation.

[0030] Optionally, for any set of time parameters, the establishment of the preset correspondence includes:

[0031] When the test contactor is closed for the mth time, a closing command is sent to the test contactor;

[0032] The closing time of the test contactor is determined based on the resistance change between the input and output terminals of the test contactor.

[0033] Send a disconnect command to the test contactor;

[0034] The disconnection time of the test contactor is determined based on the resistance change between the input and output terminals of the test contactor.

[0035] The closing and opening times of the test contactor constitute the time parameter set, and the time parameter set and m times constitute a preset correspondence relationship corresponding to the time parameter set.

[0036] According to another aspect of the present invention, an online detection device for a contactor is also provided, comprising:

[0037] The first instruction sending module is used to send a closing instruction to the contactor when it is determined that the contactor is working properly;

[0038] The closing time determination module is used to determine the current closing time of the contactor based on the resistance change between the input and output terminals of the contactor.

[0039] The second instruction sending module is used to send a disconnection instruction to the contactor;

[0040] The disconnection time determination module is used to determine the current disconnection time of the contactor based on the resistance change between the input and output terminals of the contactor.

[0041] The usage count determination module is used to determine the current usage count of the contactor based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the usage count corresponding to each time parameter group. The time parameter groups include the closing time and opening time of the contactor.

[0042] The technical solution of this invention determines the current closing time of the contactor by observing the change in resistance across the contactor when it is closed, and determines the current opening time by observing the change in resistance across the contactor when it is opened. Since a pre-established correspondence between the contactor's closing time, opening time, and number of uses is established, the current number of uses of the contactor can be determined based on the preset correspondence, which also determines the contactor's service life. This enables online detection of the contactor's service life, allowing for timely replacement of the contactor when its service life reaches its limit, thus ensuring the safe and stable operation of the power supply circuit where the contactor is located.

[0043] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart of an online detection method for a contactor provided in an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of a contactor provided in an embodiment of the present invention;

[0047] Figure 3 A flowchart of another online detection method for contactors provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the structure of an online detection device for a contactor provided in an embodiment of the present invention. Detailed Implementation

[0049] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0050] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0051] Figure 1 This is a flowchart illustrating an online detection method for a contactor provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a contactor provided in an embodiment of the present invention. This embodiment is applicable to situations where the service life of a contactor is detected online. The method can be executed by an online detection device for the contactor, which can be implemented in hardware and / or software. (See reference) Figure 1 and Figure 2 The method includes:

[0052] S110: When it is determined that the contactor is working properly, send a closing command to the contactor.

[0053] Beforehand, certain tests are conducted to ensure the contactor can close and open normally, facilitating subsequent normal closing and opening of the contactor and determining its current closing and opening times. Once the contactor is confirmed to be functioning correctly, a closing command is sent to it to control the contactor to perform the corresponding closing action. Specifically, step S110 requires the contactor to be in the open state.

[0054] S120: Determine the current closing time of the contactor based on the resistance change between the contactor's input terminal IN and output terminal OUT. That is, determine the current closing time of the contactor based on the resistance change between the contactor's input terminal IN and output terminal OUT during the first set time after sending the closing command to the contactor.

[0055] like Figure 2 As shown, the contactor includes a coil Q1 and a spring 1. The spring 1 is connected in series between the contactor's input terminal IN and output terminal OUT. The resistance between the contactor's input terminal IN and output terminal OUT is the resistance across the spring 1. The contactor also includes a DC detection (Direct Current Internal Resistance, DCIR) module, hereinafter referred to as DCIR module 2. The DCIR module is connected in parallel between the contactor's input terminal IN and output terminal OUT. It is used to obtain the resistance between the contactor's input terminal IN and output terminal OUT. Specifically, it obtains the voltage and current between the contactor's input terminal IN and output terminal OUT, and then calculates the resistance between the contactor's input terminal IN and output terminal OUT.

[0056] Before receiving a closing command, the contactor's spring is in the open state, and there is no connection between the contactor's input terminal IN and output terminal OUT, resulting in a relatively high resistance value. After receiving the closing command, the spring closes, connecting the contactor's input terminal IN and output terminal OUT, and the resistance between them changes to a relatively low value. Therefore, the operating time of the contactor's spring 1, i.e., the current closing time of the contactor, can be determined based on the change in resistance before and after receiving the closing command. In an optional embodiment, when the contactor is in the open state, the resistance between its input terminal IN and output terminal OUT stabilizes at a first stable value. The time difference between sending the closing command to the contactor and the time when the resistance between the contactor's input terminal IN and output terminal OUT stabilizes at a second stable value is taken as the contactor's closing time, where the first stable value is greater than the second stable value. If the change in resistance between the input terminal IN and the output terminal OUT of the contactor is less than the first error threshold, such as 5mΩ, within a second set time period, such as 70ms, the contactor can be considered to be stable at the first stable value. If the change in resistance between the input terminal IN and the output terminal OUT of the contactor is less than the second error threshold, such as 0.05mΩ, within a second set time period, the contactor can be considered to be stable at the second stable value.

[0057] S130: Send a disconnect command to the contactor.

[0058] After sending a closing command to the contactor, after a preset time interval such as 200ms, a closing command is sent to the contactor to control the contactor to perform the corresponding closing action.

[0059] S140: Determine the current disconnection time of the contactor based on the resistance change between the contactor's input terminal IN and output terminal OUT. That is, determine the current disconnection time of the contactor based on the resistance change between the contactor's input terminal IN and output terminal OUT after a third set time (e.g., 5ms) following the sending of the disconnection command.

[0060] Before receiving a disconnect command, the contactor's input terminal IN and output terminal OUT are connected, and the resistance between them is relatively small. When the contactor receives the disconnect command, the spring contacts open, disconnecting the connection between the contactor's input terminal IN and output terminal OUT. The resistance between the contactor's input terminal IN and output terminal OUT changes to a larger value. Therefore, the rebound time of the contactor's spring 1, i.e., the current disconnection time of the contactor, can be determined based on the change in resistance before and after receiving the disconnect command. In an optional embodiment, when the contactor is in the closed state, the resistance between its input terminal IN and output terminal OUT stabilizes at a second stable value. The time difference between the moment the disconnect command is sent to the contactor and the moment when the resistance between the contactor's input terminal IN and output terminal OUT stabilizes at the first stable value is taken as the contactor's disconnection time.

[0061] S150: Determine the current number of times the contactor is used based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the number of times each time parameter group is used. The time parameter groups include the contactor's closing time and opening time.

[0062] Multiple time parameter groups are pre-defined, with at least one of the closing and opening times differing between each group. Each time parameter group corresponds to a usage count. The current closing and opening times are considered the current time parameter group. The usage count corresponding to the current time parameter group is determined by looking up a table or interpolation from the correspondence between the multiple time parameter groups and usage counts, thus determining the current service life of the contactor. The current usage count refers to the number of times the contactor has been used since it left the factory. If the upper limit for the contactor's usage count is 10,000 times, and the current usage count is determined to be 5,000 times, then the contactor's service life is determined to be 50%. When the service life reaches 100%, the contactor needs to be replaced.

[0063] The technical solution of this invention determines the current closing time of the contactor by observing the change in resistance at both ends when the contactor is closed, and determines the current opening time by observing the change in resistance at both ends when the contactor is opened. Since a correspondence between the contactor's closing time, opening time, and number of uses is established in advance, the current number of uses of the contactor can be determined according to the preset correspondence, thereby determining the contactor's service life. This enables online detection of the contactor's service life, allowing for timely replacement of the contactor when its service life reaches its limit, ensuring the safe and stable operation of the power supply circuit where the contactor is located.

[0064] Figure 3A flowchart of another online detection method for contactors provided in an embodiment of the present invention is shown below. Figure 2 and Figure 3 Optionally, the method includes:

[0065] S111: Send a closing command to the contactor.

[0066] When determining the current number of times a contactor has been used based on its current closing and opening times, it is necessary to ensure that the contactor is functioning correctly, i.e., it can close and open normally. Steps S111-161 are the process of testing whether the contactor is functioning correctly.

[0067] Send a closing command to the contactor to control the contactor to perform the corresponding closing action.

[0068] S121: Obtain the resistance value between the input terminal IN and the output terminal OUT of the contactor, and use it as the first resistance value.

[0069] After sending a closing command to the contactor, the resistance between the contactor's input terminal IN and output terminal OUT can be obtained through DCIR module 2 after a first set time interval, such as 50ms. The first set time interval can be the maximum time required for the contactor to perform the closing action. Since the contactor's spring action time is usually less than or equal to 50ms when it is normally closed, obtaining the resistance value at both ends of the contactor after the first set time interval ensures that the first resistance value collected is the resistance value when the contactor is in the closed state. This avoids inaccurate resistance value acquisition caused by using the resistance value at both ends of the contactor before it has completed closing, which could lead to subsequent misdiagnosis of faults.

[0070] S131: When the first resistance of the contactor is less than or equal to the first threshold value, it is determined that the contactor is closed normally.

[0071] The first threshold is the maximum resistance value between the contactor's input terminal IN and output terminal OUT when the contactor is in the closed state. For example, if the resistance between the contactor's input terminal IN and output terminal OUT, obtained by the DCIR module 2, is 0.3mΩ when the contactor is in the closed state at the time of manufacture, then the first threshold is set to 0.3mΩ. When the first resistance value of the contactor is less than or equal to the first threshold, it can be determined that the resistance between the contactor's input terminal IN and output terminal OUT is small, indicating a connection between them, and thus confirming that the contactor is closing normally.

[0072] Optionally, when the first resistance of the contactor is greater than the first threshold, the contactor is determined to be abnormally closed, and a first alarm signal is output.

[0073] When the first resistance of the contactor exceeds the first threshold, it indicates that the contactor's input terminal IN and output terminal OUT are not connected, the contactor fails to close, and a contact malfunction occurs. A first alarm signal is then output to remind the user to perform timely maintenance. This first alarm signal can be a voice signal such as "Contactor closure abnormality."

[0074] S141: After a preset interval, send a disconnect command to the contactor.

[0075] The preset duration can be 300ms to ensure that after the contactor is stably closed, a disconnect command is sent to the contactor after a certain interval to control the contactor to perform the corresponding disconnect action.

[0076] S151: Obtain the resistance value between the input terminal IN and the output terminal OUT of the contactor, and use it as the second resistance value.

[0077] After sending a disconnect command to the contactor, the resistance between the contactor's input terminal IN and output terminal OUT can be obtained through DCIR module 2 after a third set time interval, such as 5ms. This third set time interval can be the maximum time required for the contactor to perform the disconnect action. Because the spring return time of the contactor during normal disconnection is usually less than or equal to 5ms, obtaining the resistance value across the contactor after the third set time interval ensures that the second resistance value is the resistance value when the contactor is in the disconnection completed state. This avoids inaccurate resistance value acquisition due to using the resistance value at both ends of the contactor before the disconnection is complete, which could lead to subsequent misdiagnosis of faults.

[0078] S161: When the second resistance of the contactor is greater than the first threshold, it is determined that the contactor is normally disconnected.

[0079] When the second resistance of the contactor is greater than the first threshold, it can be determined that the resistance between the input terminal IN and the output terminal OUT of the contactor is large, and the input terminal IN and the output terminal OUT are in an open state, thus confirming that the contactor is disconnected normally.

[0080] Optionally, when the second resistance of the contactor is less than or equal to the first threshold, the contactor is determined to be abnormally disconnected, and a second alarm signal is output.

[0081] When the first resistance of the contactor is less than or equal to the first threshold, it indicates that there is a connection between the contactor's input terminal IN and output terminal OUT. If the contactor becomes stuck, it will fail to disconnect and output a second alarm signal to remind the user to perform timely maintenance. The second alarm signal can be a voice signal such as "Contactor disconnection abnormality".

[0082] S171: When the contactor closes and opens normally, the contactor is considered to be working normally.

[0083] S181: When it is determined that the contactor is working properly, send a closing command to the contactor.

[0084] S191: Determine the current closing time of the contactor based on the resistance change between the input terminal IN and the output terminal OUT of the contactor.

[0085] The time difference between the moment the closing command is sent to the contactor and the moment when the resistance between the contactor's input terminal IN and output terminal OUT changes to the first threshold value is taken as the current closing time of the contactor.

[0086] The first threshold is the maximum resistance value between the contactor's input terminal IN and output terminal OUT when the contactor is in the closed state. After a closing command is sent to the contactor, the contactor's spring contacts close. After the contactor spring contacts close, the resistance value between the contactor's input terminal IN and output terminal OUT will change from a relatively large value to the first threshold. The moment when the resistance value between the contactor's input terminal IN and output terminal OUT changes to the first threshold indicates that the contactor is in the closed state. Therefore, the time difference between the moment the closing command is sent to the contactor and the moment when the resistance value between the contactor's input terminal IN and output terminal OUT changes to the first threshold can represent the contactor's spring contact action time, that is, the current closing time of the contactor.

[0087] Optionally, when it is determined that the number of times the contactor is used is less than the preset number of times it is used, the first threshold is set between 0.2mΩ and 0.35mΩ; when it is determined that the number of times the contactor is used is greater than or equal to the preset number of times it is used, the first threshold is set between 0.45mΩ and 0.6mΩ.

[0088] When a contactor is initially put into use and used infrequently, the resistance between its input terminal IN and output terminal OUT remains at the factory-measured value, approximately 0.3 mΩ, when the contactor is in the closed state. As the number of uses increases, arcing can easily occur at the contact point between the spring 1 and the contactor, leading to carbonization or ablation. This causes the resistance between the input terminal IN and output terminal OUT to increase, for example, to 0.5 mΩ, when the contactor is in the closed state. Therefore, setting different first thresholds based on the number of times the contactor has been used can improve the accuracy of determining the opening and closing times. For example, the preset number of uses can be the minimum value representing the change in resistance between the input terminal IN and output terminal OUT when the contactor is in the closed state compared to its factory value, such as 10 times.

[0089] S201: Send a disconnect command to the contactor.

[0090] S211: Determine the current disconnection time of the contactor based on the resistance change between the input terminal IN and the output terminal OUT of the contactor.

[0091] The time difference between the moment the disconnection command is sent to the contactor and the moment when the resistance between the input and output terminals of the contactor changes to the second threshold is taken as the current disconnection time of the contactor; the second threshold is greater than the first threshold.

[0092] The second threshold is the minimum resistance between the contactor's input terminal IN and output terminal OUT when the contactor is in the open state. After a disconnect command is sent to the contactor, the contactor's spring contacts open. After the contactor spring contacts open, the resistance between the contactor's input terminal IN and output terminal OUT will change from a small value to the second threshold. The moment when the resistance between the contactor's input terminal IN and output terminal OUT reaches the second threshold indicates that the contactor is in the open state. Therefore, the time difference between the moment a closing command is sent to the contactor and the moment when the resistance between the contactor's input terminal IN and output terminal OUT reaches the second threshold can be used to characterize the contactor's spring contact rebound time, which is also the current disconnect time of the contactor.

[0093] For example, the first threshold can be 0.5mΩ and the second threshold can be 1mΩ.

[0094] S221: Determine the current number of times the contactor is used based on the current closing time, the current opening time, and the preset correspondence.

[0095] When a reference time parameter group exists among multiple time parameter groups, the number of times the reference time parameter group is used is taken as the current number of times the contactor is used; the closing time in the reference time parameter group is equal to the current closing time of the contactor, and the opening time in the reference time parameter group is equal to the current opening time of the contactor.

[0096] The preset correspondence may include a preset compensation table, which includes multiple sets of time parameter groups and the number of times each time parameter group is used. For example, the header row of the preset compensation table has different closing times, the header column has different opening times, and the values ​​of the remaining cells excluding the header row and column are the number of times they are used. For example, the preset compensation table includes multiple closing times of 10ms, 30ms, 50ms, and 70ms, and multiple opening times of 1ms, 3ms, 5ms, and 7ms, respectively. The preset compensation table includes sixteen sets of time parameters, namely (10ms, 1ms), (10ms, 3ms), (10ms, 5ms), (10ms, 7ms), (30ms, 1ms), (30ms, 3ms), (30ms, 5ms), (30ms, 7ms), (50ms, 1ms), (50ms, 3ms), (50ms, 5ms), (50ms, 7ms), (70ms, 1ms), (70ms, 3ms), (70ms, 5ms), and (70ms, 7ms). For example, using (70ms, 7ms) as a reference time parameter set, the closing time in the reference time parameter set is equal to 70ms, the opening time is equal to 7ms, and the contactor corresponding to the reference time parameter set is used 100 times. That is, after the contactor is used 100 times, its closing time will be 70ms and its opening time will be 7ms. The number of times the contactor is used can be represented by the number of times the contactor is closed. When the above steps determine that the current closing time of the contactor is 70ms and the current opening time is 7ms, the corresponding number of uses corresponding to the reference time parameter set (70ms, 7ms) can be determined by looking up a table, thus determining that the current number of uses of the contactor is 100 times, and thus determining the service life of the contactor.

[0097] When there is no reference time parameter group among multiple time parameter groups, the current number of times the contactor is used is determined by interpolation calculation.

[0098] Specifically, if the current closing time of the contactor is the same as one of the closing times in a preset correspondence of multiple time parameter groups, and the current opening time is different from any of the opening times in the preset correspondence, then the current service life of the contactor is determined by interpolation based on the two time parameter groups that are the same as the current closing time and adjacent to the current opening time, and their corresponding usage counts. If the current closing time of the contactor is different from any of the closing times in the preset correspondence, and the current opening time is the same as one of the opening times in the preset correspondence, then the current service life of the contactor is determined by interpolation based on the two time parameter groups that are the same as the current opening time and adjacent to the current closing time, and their corresponding usage counts. If the current closing time of the contactor is different from any of the closing times in the preset correspondence, and the current opening time is different from any of the opening times in the preset correspondence, then the first time parameter group and its corresponding usage counts are determined by interpolation based on the first opening time and the two time parameter groups containing the two closing times adjacent to the current closing time. Based on the second disconnection time and the two time parameter groups containing the two closing times adjacent to the current closing time, the second time parameter group and its corresponding usage count are determined by interpolation. Then, based on the first time parameter group, the second time parameter group, and their respective usage counts, the current usage time and the usage count corresponding to the current closing time are determined by interpolation. The first disconnection time and the second disconnection time are two disconnection times adjacent to the current disconnection time included in a preset correspondence.

[0099] For example, if the current closing time of the contactor is determined to be 60ms and the opening time to be 7ms through the above steps, then the number of times (60ms, 7ms) is used is determined by linear interpolation using the time parameter set (50ms, 7ms) and its corresponding usage count, and (70ms, 7ms) and its corresponding usage count. Similarly, if the current closing time of the contactor is determined to be 50ms and the opening time to be 6ms through the above steps, then the number of times (50ms, 6ms) is determined by linear interpolation using the time parameter set (50ms, 5ms) and its corresponding usage count, and (50ms, 7ms) and its corresponding usage count. If the current closing time of the contactor is determined to be 60ms and the opening time to be 6ms through the above steps, then the number of times the first time parameter group (60ms, 5ms) is used is determined by linear interpolation based on the time parameter group (50ms, 5ms) and its corresponding usage count, and (70ms, 5ms) and its corresponding usage count. Based on the time parameter group (50ms, 7ms) and its corresponding usage count, and (70ms, 7ms) and its corresponding usage count, the number of times the second time parameter group (60ms, 7ms) is used is determined by linear interpolation. Finally, based on the number of times the contactor is used (60ms, 6ms) and (60ms, 7ms), the number of times the contactor is used is determined.

[0100] Optionally, for any set of time parameters, the establishment of a preset correspondence includes:

[0101] When the test contactor is closed for the mth time, a closing command is sent to the test contactor;

[0102] The closing time of the test contactor is determined based on the resistance change between the input terminal IN and the output terminal OUT of the test contactor.

[0103] Send a disconnect command to the test contactor;

[0104] The disconnection time of the test contactor is determined based on the resistance change between the input terminal IN and the output terminal OUT of the test contactor.

[0105] The closing and opening times of the test contactor constitute a time parameter set, and the time parameter set and m times constitute a preset correspondence between the time parameter set and the time parameter set.

[0106] Specifically, in the preliminary testing phase, a test contactor is selected. This test contactor is from the same batch as the contactor to be tested online, and all parameters are identical. This ensures that the preset correspondence established based on the test contactor applies to the contactor to be tested online. Taking a preset correspondence of 100 uses as an example, after the contactor has been used 99 times, a closing command is sent to the test contactor to close it for the 100th time, i.e., m = 100. Then, based on the resistance change between the input terminal IN and the output terminal OUT of the test contactor, the closing time of the test contactor is determined, which is the same as step S191 and will not be repeated here. After a preset interval, a disconnection command is sent to the test contactor. Then, based on the resistance change between the input terminal IN and the output terminal OUT of the test contactor, the disconnection time of the test contactor is determined, which is the same as step S202 and will not be repeated here. Thus, the closing and disconnection times corresponding to 100 uses of the contactor can be determined.

[0107] This invention also provides an online testing device for contactors. Figure 4 This is a schematic diagram of the structure of an online detection device for a contactor provided in an embodiment of the present invention, with reference to... Figure 4 The device includes:

[0108] The first instruction sending module 10 is used to send a closing instruction to the contactor when it is determined that the contactor is working properly;

[0109] The closing time determination module 20 is used to determine the current closing time of the contactor based on the resistance change between the input and output terminals of the contactor.

[0110] The second instruction sending module 30 is used to send a disconnection instruction to the contactor;

[0111] The disconnection time determination module 40 is used to determine the current disconnection time of the contactor based on the resistance change between the input and output terminals of the contactor.

[0112] The usage count determination module 50 is used to determine the current usage count of the contactor based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the usage count corresponding to each time parameter group. The time parameter groups include the closing time and opening time of the contactor.

[0113] The beneficial effects of the online detection device for contactors are the same as those of the online detection method for contactors, and will not be repeated here.

[0114] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0115] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An online detection method for a contactor, characterized in that, include: Once it is confirmed that the contactor is working properly, a closing command is sent to the contactor; The current closing time of the contactor is determined based on the resistance change between the input and output terminals of the contactor. Send a disconnect command to the contactor; The current disconnection time of the contactor is determined based on the resistance change between the input and output terminals of the contactor. The current number of times the contactor is used is determined based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the number of times each time parameter group is used. The time parameter groups include the closing time and opening time of the contactor.

2. The online detection method for contactors according to claim 1, characterized in that, Determining the current closing time of the contactor based on the resistance change between its input and output terminals includes: The time difference between the moment the closing command is sent to the contactor and the moment when the resistance between the input and output terminals of the contactor changes to a first threshold value is taken as the current closing time of the contactor.

3. The online detection method for contactors according to claim 2, characterized in that, Determining the current disconnection time of the contactor based on the resistance change between its input and output terminals includes: The time difference between the moment the disconnection command is sent to the contactor and the moment when the resistance between the input and output terminals of the contactor changes to a second threshold is taken as the current disconnection time of the contactor; the second threshold is greater than the first threshold.

4. The online detection method for contactors according to claim 2, characterized in that, When it is determined that the number of times the contactor has been used is less than the preset number of times it has been used, the first threshold is set between 0.2mΩ and 0.35mΩ; When it is determined that the number of times the contactor is used is greater than or equal to the preset number of times it is used, the first threshold is set between 0.45mΩ and 0.6mΩ.

5. The online detection method for contactors according to claim 1, characterized in that, Before sending a closing command to the contactor, the following is also included: Send a closing command to the contactor; Obtain the resistance value between the input and output terminals of the contactor, and use it as the first resistance value; When the first resistance value of the contactor is less than or equal to the first threshold value, it is determined that the contactor is closed normally. After a preset time interval, a disconnect command is sent to the contactor; Obtain the resistance value between the input and output terminals of the contactor, and use it as the second resistance value; When the second resistance value of the contactor is greater than the first threshold, it is determined that the contactor is normally disconnected. When the contactor closes and opens normally, it is determined that the contactor is working properly.

6. The online detection method for a contactor according to claim 5, characterized in that, When the first resistance of the contactor is greater than the first threshold, it is determined that the contactor is abnormally closed, and a first alarm signal is output.

7. The online detection method for a contactor according to claim 5, characterized in that, When the second resistance value of the contactor is less than or equal to the first threshold, the contactor is determined to be abnormally disconnected, and a second alarm signal is output.

8. The online detection method for a contactor according to claim 1, characterized in that, The step of determining the current number of times the contactor is used based on its current closing time, current opening time, and a preset correspondence includes: When a reference time parameter group exists among the multiple time parameter groups, the number of times the reference time parameter group is used is taken as the current number of times the contactor is used; the closing time in the reference time parameter group is equal to the current closing time of the contactor, and the opening time in the reference time parameter group is equal to the current opening time of the contactor; If the reference time parameter group is not present in any of the multiple time parameter groups, the current number of times the contactor is used is determined by interpolation.

9. The online detection method for a contactor according to claim 1, characterized in that, For any set of time parameters, the establishment of the preset correspondence includes: When the test contactor is closed for the mth time, a closing command is sent to the test contactor; The closing time of the test contactor is determined based on the resistance change between the input and output terminals of the test contactor. Send a disconnect command to the test contactor; The disconnection time of the test contactor is determined based on the resistance change between the input and output terminals of the test contactor. The closing and opening times of the test contactor constitute the time parameter set, and the time parameter set and m times constitute a preset correspondence relationship corresponding to the time parameter set.

10. An online detection device for a contactor, characterized in that, include: The first instruction sending module is used to send a closing instruction to the contactor when it is determined that the contactor is working properly; The closing time determination module is used to determine the current closing time of the contactor based on the resistance change between the input and output terminals of the contactor. The second instruction sending module is used to send a disconnection instruction to the contactor; The disconnection time determination module is used to determine the current disconnection time of the contactor based on the resistance change between the input and output terminals of the contactor. The usage count determination module is used to determine the current usage count of the contactor based on the current closing time, the current opening time, and a preset correspondence. The preset correspondence includes multiple time parameter groups and the usage count corresponding to each time parameter group. The time parameter groups include the closing time and opening time of the contactor.

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