Method and device for determining the length of time for which the main circuit of a rectifier is closed

Abstract

The application provides a method and device for determining the main circuit closing duration of a rectifier, and relates to the technical field of power electronics. The method comprises the following steps: collecting the DC bus voltage and three-phase incoming line currents of the rectifier; determining a first time point at which the DC bus voltage is greater than or equal to a first threshold value; determining the first incoming line current greater than or equal to a second threshold value as the first-phase incoming line current, and determining a second time point at which the first-phase incoming line current is greater than or equal to the second threshold value for the first time; determining the functional relationship between the first-phase incoming line current and the time point from the second time point; determining the third time point corresponding to the maximum value of the first-phase incoming line current according to the functional relationship; and determining the main circuit closing duration as the difference between the third time point and the first time point. The application can determine the main circuit closing duration of the rectifier, which is beneficial to the predictive diagnosis and maintenance of the rectifier in advance.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more particularly to a method and apparatus for determining the closing time of the main circuit of a rectifier. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] During the use of the rectifier, after the pre-charging is completed, the main circuit breaker needs to be closed to close the main circuit. Since the main circuit breaker requires a mechanical device to complete the closing, arcing, and arc extinguishing actions, and there are delays, jitters, and changes inside the main circuit breaker, in addition, due to errors in the mechanical structure of the rectifier design, the timing of the delay relays is also inconsistent. All these factors make it difficult to determine the closing time of the rectifier's main circuit. Because it is difficult to determine the closing time of the rectifier's main circuit, it is impossible to perform predictive diagnosis and maintenance of the rectifier before it fails. Summary of the Invention

[0004] This invention provides a method for determining the main circuit closing time of a rectifier, which facilitates predictive diagnosis and maintenance of the rectifier in advance. The method includes:

[0005] Collect the DC bus voltage and three-phase input current of the rectifier;

[0006] Determine the first moment when the DC bus voltage is greater than or equal to the first threshold.

[0007] The first phase input current is defined as the first phase input current when the first phase input current is greater than or equal to the second threshold. The second moment when the first phase input current is greater than or equal to the second threshold is determined.

[0008] Starting from the second moment, determine the functional relationship between the first phase incoming current and the elapsed time.

[0009] Based on the aforementioned functional relationship, determine the third moment corresponding to the maximum value of the first phase incoming current;

[0010] The difference between the third time point and the first time point is used to determine the duration of the main loop closure.

[0011] This invention provides a device for determining the main circuit closing time of a rectifier, which is used to determine the main circuit closing time of the rectifier, facilitating predictive diagnosis and maintenance of the rectifier in advance. The device includes:

[0012] The signal acquisition module is used to acquire the DC bus voltage and three-phase input current of the rectifier;

[0013] The first moment determination module is used to determine the first moment when the DC bus voltage is greater than or equal to the first threshold.

[0014] The second moment determination module is used to determine the first phase incoming current as the first phase incoming current when the first phase incoming current is greater than or equal to the second threshold among the three phase incoming currents, and to determine the second moment when the first phase incoming current is greater than or equal to the second threshold.

[0015] The function relationship determination module is used to determine the function relationship between the first phase incoming current and the elapsed time, starting from the second time point;

[0016] The third moment determination module is used to determine the third moment corresponding to the maximum value of the first phase incoming current based on the functional relationship.

[0017] The closing duration determination module is used to determine the main loop closing duration by the difference between the third time point and the first time point.

[0018] An embodiment of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a method for determining the main circuit closing time of a rectifier.

[0019] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a method for determining the main circuit closure duration of a rectifier.

[0020] An embodiment of the present invention proposes a computer program product, which includes a computer program that, when executed by a processor, implements a method for determining the main circuit closure duration of a rectifier.

[0021] The method and apparatus for determining the main circuit closing time of a rectifier proposed in this invention can solve the problem in the prior art that it is difficult to determine the main circuit closing time of a rectifier, making it impossible to perform predictive diagnosis and maintenance of the rectifier in advance. This invention collects the DC bus voltage and three-phase input current of the rectifier; determines the first moment when the DC bus voltage is greater than or equal to a first threshold; identifies the first input current among the three-phase input currents that is greater than or equal to a second threshold as the first phase input current; determines the second moment when the first phase input current is greater than or equal to the second threshold; from the second moment, determines the functional relationship between the first phase input current and the elapsed time; based on the functional relationship, determines the third moment corresponding to the maximum value of the first phase input current; and determines the main circuit closing time by the difference between the third moment and the first moment. This invention enables the determination of the main circuit closing time of the rectifier, facilitating predictive diagnosis and maintenance of the rectifier before a failure occurs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating the method for determining the main circuit closure duration of the rectifier in an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a high-power rectifier circuit in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the DC bus voltage during the rectifier pre-charging process in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the three-phase input current during the rectifier pre-charging process in an embodiment of the present invention;

[0027] Figure 5 This is a specific example diagram of the method for determining the main circuit closing time of the rectifier in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the device for determining the main circuit closing time of the rectifier in an embodiment of the present invention;

[0029] Figure 7 This is a specific example diagram of the device for determining the main circuit closing time of the rectifier in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0032] In this document, the term "and / or" merely describes a relationship, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0033] In the description of this specification, the terms "comprising," "including," "having," and "containing" are open-ended terms, meaning that they include but are not limited to. The terms "an embodiment," "a specific embodiment," "some embodiments," and "for example," etc., refer to specific features, structures, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of this application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0034] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0035] Figure 1 This is a flowchart illustrating the method for determining the main circuit closing time of the rectifier in an embodiment of the present invention. Figure 1 As shown, the method includes:

[0036] Step 101: Collect the DC bus voltage and three-phase input current of the rectifier;

[0037] Step 102: Determine the first moment when the DC bus voltage is greater than or equal to the first threshold.

[0038] Step 103: Determine the first phase incoming current as the first phase incoming current when the first phase incoming current is greater than or equal to the second threshold. Determine the second moment when the first phase incoming current is greater than or equal to the second threshold.

[0039] Step 104: Starting from the second moment, determine the functional relationship between the first phase incoming current and the elapsed time.

[0040] Step 105: Based on the aforementioned functional relationship, determine the third moment corresponding to the maximum value of the first phase incoming current;

[0041] Step 106: Determine the duration of the main loop closure by the difference between the third time point and the first time point.

[0042] Depend on Figure 1As shown in the flowchart, this embodiment of the invention collects the DC bus voltage and three-phase input current of the rectifier, determines the first moment when the DC bus voltage is greater than or equal to a first threshold, identifies the first input current that is greater than or equal to a second threshold, defines it as the first phase input current, determines the second moment when the first phase input current is greater than or equal to the second threshold, and from the second moment onwards, determines the functional relationship between the first phase input current and the elapsed time. Based on this functional relationship, it determines the third moment corresponding to the maximum value of the first phase input current, and determines the difference between the third moment and the first moment as the main circuit closing duration. By determining the main circuit closing duration of the rectifier, this embodiment of the invention can perform predictive diagnosis and maintenance of the rectifier before a failure occurs.

[0043] The embodiments of the present invention are particularly applicable to determining the main circuit closing time of high-power rectifiers. Figure 2 This is a schematic diagram of a high-power rectifier circuit in an embodiment of the present invention, with reference to... Figure 2 C1, C2, and C3 are DC capacitors; D1, D2, D3, D4, D5, and D6 are diodes; G1, G2, G3, G4, G5, and G6 are transistors; L11, L12, and L13 are incoming line reactors; R1, R2, and R3 are protective resistors; Ru, Rv, and Rw are pre-charging resistors; Sw1 is a three-phase contactor; Sw2 is a main circuit breaker; both the three-phase contactor and the main circuit breaker include moving contacts 1, 3, and 5 and stationary contacts 2, 4, and 6; during the pre-charging process of the high-power rectifier, after receiving the closing command, the three-phase contactor Sw1 is energized, and the three-phase moving contacts gradually approach the three-phase stationary contacts. When the moving and stationary contacts are fully in contact, the contactor energizing action is completed. Because the moving contacts of the three-phase contactor Sw1 cannot operate completely synchronously during the closing process, some moving contacts may contact the stationary contacts first. When the first two moving and stationary contacts close, a single-phase full-bridge rectifier circuit is formed, which charges the DC capacitors. Assuming that the moving and stationary contacts of phase U and phase V contact first, forming a single-phase full-bridge rectifier circuit, the charging current I flows to the positive DC bus after the moving contact 1 and stationary contact 2, and the moving contact 3 and stationary contact 4 of the three-phase contactor Sw1, through the pre-charging resistor Ru, the input reactor L11, and the diode D1 of the insulated-gate bipolar transistor IGBT, charging the DC capacitors C1, C2, and C3. Then, after passing through the diode D4 of the insulated-gate bipolar transistor IGBT, the input reactor L12, and the pre-charging resistor Rv, it passes through the stationary contact 4 and the moving contact 3 of the three-phase contactor Sw1, forming a complete closed current loop between phase U and phase V. Figure 3 This is a schematic diagram of the DC bus voltage during the rectifier pre-charging process in an embodiment of the present invention. Figure 4 This is a schematic diagram of the three-phase input current during the rectifier pre-charging process in an embodiment of the present invention, with reference to... Figure 3 , Figure 4 After the three moving and stationary contacts of the rectifier are fully closed, a three-phase full-bridge rectifier circuit is formed between phases U, V, and W, achieving simultaneous charging of the three phases. The DC bus voltage gradually increases, while the three-phase incoming current gradually decreases. When the DC bus voltage is greater than or equal to 85% of the standard voltage of the high-power rectifier, a command to close the main circuit breaker Sw2 is issued. After a 1-second delay, a command to open the three-phase contactor Sw1 is issued. At the instant the main circuit breaker Sw2 closes, a large inrush current is generated, and the DC bus voltage rises rapidly. Because the main circuit breaker Sw2 has the characteristic of closing at a voltage zero-crossing point, after receiving a closing command, it needs to wait for the next zero-crossing point to arrive. For a 50 Hz power grid, a voltage zero-crossing point occurs every 10 ms, resulting in a 10 ms delay in the closing time of the main circuit breaker. Simultaneously, for the operation of the moving and stationary contacts, the main circuit breaker requires a mechanical device operation time to complete the closing, arcing, and arc extinguishing actions. Furthermore, there are internal delays, jitter, and variations within the main circuit breaker. In addition, due to errors in the mechanical structure of the high-power rectifier design, the operating times of the time-delay relays are inconsistent. These factors all lead to changes in the actual main circuit closing time, making it difficult to determine the main circuit closing time of the high-power rectifier. Therefore, this invention can determine the main circuit closing time, solving the problem of difficulty in determining the main circuit closing time of a high-power rectifier and the inability to perform predictive diagnosis and maintenance of the high-power rectifier in advance.

[0044] To provide a clearer explanation of the method for determining the main circuit closing time of the rectifier, each step will be explained in detail below.

[0045] In one embodiment of the present invention, for step 102, based on the collected DC bus voltage and the set first threshold, a first moment when the DC bus voltage is greater than or equal to the first threshold is determined, wherein the first threshold is determined according to the standard voltage of the rectifier; in a specific embodiment, the first threshold can be set to 85% of the standard voltage of the rectifier.

[0046] In one embodiment of the present invention, for step 103, based on the collected three-phase input current and the set second threshold, the input current that is first greater than or equal to the second threshold among the three-phase input currents is determined as the first phase input current, and the second moment when the first phase input current is first greater than or equal to the second threshold is determined; in a specific embodiment, the second threshold can be set to 10% of the rectifier rated current.

[0047] In one embodiment of the present invention, starting from the second moment, the effective value of the first phase incoming current is determined within a preset time window. Based on the first phase incoming current at the second moment and the effective value of the first phase incoming current within the preset time window, a functional relationship between the first phase incoming current and the elapsed time is determined; wherein, the functional relationship is an exponential function; for example: starting from the second moment, every 20ms is set as a time window, and the effective value of the first phase incoming current is determined within each time window. The first phase incoming current at the second moment and the effective value of the first phase incoming current within each time window are fitted to determine the exponential function between the first phase incoming current and the elapsed time. The exponential function between the first phase incoming current and the elapsed time is expressed by the following formula:

[0048]

[0049] Where I is the first phase incoming current; k is the first constant; τ is the equivalent time constant; and t is the duration of the first phase incoming current.

[0050] In another embodiment of the present invention, at a preset time after the second time, a 20ms time window is set, and the effective value of the first phase incoming current is determined within the 20ms time window. Based on the first phase incoming current at the second time, the preset duration, and the effective value of the first phase incoming current within the 20ms time window, the constant parameter of the exponential function is determined, and the exponential function of the first phase incoming current and the elapsed time is obtained.

[0051] In practice, the effective value of the first phase incoming current is determined within a preset time window using the following formula:

[0052]

[0053] Among them, RMS I t is the effective value of the first phase incoming current; t0 is the initial value of the preset time window; Δt is the length of the preset time window; I(t) is the first phase incoming current.

[0054] In one embodiment of the present invention, the maximum value of the first-phase incoming current is determined based on the functional relationship between the first-phase incoming current and the elapsed time. Then, based on the maximum value of the first-phase incoming current and the functional relationship between the first-phase incoming current and the elapsed time, the third time corresponding to the maximum value of the first-phase incoming current is determined. At the instant the main circuit breaker closes, an impact occurs on the three-phase incoming current. The maximum value of the first-phase incoming current occurs before the second time, and the first-phase incoming current decays according to an exponential function of the first-phase incoming current and the elapsed time. In specific implementation, the exponential function of the first-phase incoming current and the elapsed time can be calculated to determine the maximum value of the first-phase incoming current before the second time. Then, based on the maximum value of the first-phase incoming current and the exponential function of the first-phase incoming current and the elapsed time, the third time corresponding to the maximum value of the first-phase incoming current is determined.

[0055] In one embodiment of the present invention, for step 106, the difference between the third time and the first time is determined as the main circuit closing time; for example, the first time when the DC bus voltage of the rectifier is greater than the first threshold is 0.379 seconds, the third time corresponding to the maximum value of the first phase input current is 1.54 seconds, and the main circuit closing time of the rectifier is determined to be 1.161 seconds.

[0056] Figure 5 This is a specific example diagram of the method for determining the main circuit closing time of the rectifier in an embodiment of the present invention. (Refer to...) Figure 5 The detailed process for comparing the main circuit closing time of the rectifier includes:

[0057] Step 501: Compare the determined main circuit closing time with the main circuit closing reference time; the main circuit closing reference time is determined based on the main circuit closing time when the rectifier is working normally.

[0058] Step 502: When the deviation between the determined main circuit closing time and the main circuit closing reference time is greater than the preset deviation threshold, a rectifier inspection notification is issued.

[0059] Step 503: When the deviation between the determined main circuit closing time and the main circuit closing reference time is less than or equal to the preset deviation threshold, it is determined that the rectifier does not need to be checked.

[0060] In one embodiment of the present invention, the main circuit closing reference duration is determined based on the main circuit closing time during normal operation of the rectifier. Each time the rectifier starts working, the main circuit closing time needs to be determined. If the deviation between the determined main circuit closing time and the main circuit closing reference duration is greater than a preset deviation threshold, a rectifier inspection notification is issued. The preset deviation threshold can be set to 20%. The setting of the preset deviation threshold needs to consider the inconsistency of the closing action of the rectifier's three-phase contactors and the jitter error at the closing time; it is an empirical value for industrial field applications. If the deviation between the main circuit closing time and the main circuit closing reference duration is greater than 200ms, the rectifier needs to be stopped immediately; otherwise, it will cause the rectifier to be temporarily disconnected from the incoming three-phase AC power grid, resulting in rectifier damage. If the deviation between the main circuit closing time and the main circuit closing reference duration is less than 200ms but greater than 20ms, it is necessary to check whether the rectifier's time relay has deviated.

[0061] It should be noted that although the operation of the method of the present invention has been described in a specific order in the above embodiments and figures, this does not require or imply that the operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0062] The implementation of the rectifier main circuit closing time determination device can refer to the implementation of the above method, and repeated details will not be elaborated further. The term "module" or "unit" used below can refer to a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0063] Based on the same inventive concept, this invention also proposes a device for determining the main circuit closing time of a rectifier, such as... Figure 6 As shown, the device includes:

[0064] The signal acquisition module 601 is used to acquire the DC bus voltage and three-phase input current of the rectifier.

[0065] The first moment determination module 602 is used to determine the first moment when the DC bus voltage is greater than or equal to the first threshold.

[0066] The second moment determination module 603 is used to determine the first phase input current as the first phase input current when the first phase input current is greater than or equal to the second threshold among the three phase input currents, and to determine the second moment when the first phase input current is greater than or equal to the second threshold.

[0067] The function relationship determination module 604 is used to determine the function relationship between the first phase incoming current and the elapsed time, starting from the second time moment;

[0068] The third moment determination module 605 is used to determine the third moment corresponding to the maximum value of the first phase incoming current according to the functional relationship.

[0069] The closing duration determination module 606 is used to determine the closing duration of the main circuit by the difference between the third time and the first time.

[0070] In one embodiment of the present invention, the first threshold is determined based on the standard voltage of the rectifier.

[0071] In one embodiment of the present invention, the second threshold is determined based on the rated current of the rectifier.

[0072] In one embodiment of the present invention, the function relationship determination module 604 is specifically used for:

[0073] Starting from the second moment, determine the effective value of the first phase incoming current within a preset time window;

[0074] Based on the first phase incoming current at the second moment and the effective value of the first phase incoming current within the preset time window, the functional relationship between the first phase incoming current and the elapsed time is determined; wherein, the functional relationship is an exponential function.

[0075] In one embodiment of the present invention, the third time-determining module 605 is specifically used for:

[0076] Based on the aforementioned functional relationship, determine the maximum value of the first phase incoming current;

[0077] Based on the maximum value of the first phase incoming current and the aforementioned functional relationship, the third moment corresponding to the maximum value of the first phase incoming current is determined.

[0078] Figure 7 This is a specific example diagram of the device for determining the main circuit closure duration of the rectifier in an embodiment of the present invention. For example... Figure 7 As shown, in one embodiment of the present invention, Figure 6 The device for determining the main circuit closing time of the rectifier shown also includes:

[0079] The duration determination module 701 is used to compare the determined main circuit closing duration with the main circuit closing reference duration; the main circuit closing reference duration is determined based on the main circuit closing duration when the rectifier is working normally.

[0080] The notification module 702 is used to issue a rectifier check notification when the deviation between the determined main circuit closing time and the main circuit closing reference time is greater than a preset deviation threshold.

[0081] It should be noted that although several modules of the rectifier main circuit closing time determination device are mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.

[0082] Based on the aforementioned inventive concept, such as Figure 8 As shown, the present invention also proposes a computer device 800, including a memory 801, a processor 802, and a computer program 803 stored in the memory 801 and executable on the processor 802. When the processor 802 executes the computer program 803, it implements the aforementioned method for determining the main circuit closing time of the rectifier.

[0083] Based on the aforementioned inventive concept, the present invention proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned method for determining the main circuit closure duration of a rectifier.

[0084] Based on the aforementioned inventive concept, the present invention proposes a computer program product, which includes a computer program that, when executed by a processor, implements a method for determining the main circuit closure duration of a rectifier.

[0085] The method and apparatus for determining the main circuit closing time of a rectifier proposed in this invention can solve the problem in the prior art that it is difficult to determine the main circuit closing time of a rectifier, making it impossible to perform predictive diagnosis and maintenance of the rectifier in advance. This invention collects the DC bus voltage and three-phase input current of the rectifier; determines the first moment when the DC bus voltage is greater than or equal to a first threshold; identifies the first input current among the three-phase input currents that is greater than or equal to a second threshold as the first phase input current; determines the second moment when the first phase input current is greater than or equal to the second threshold; from the second moment, determines the functional relationship between the first phase input current and the elapsed time; based on the functional relationship, determines the third moment corresponding to the maximum value of the first phase input current; and determines the main circuit closing time by the difference between the third moment and the first moment. This invention enables the determination of the main circuit closing time of the rectifier, facilitating predictive diagnosis and maintenance of the rectifier before a failure occurs.

[0086] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0087] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0088] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0089] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0090] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of determining a main circuit closing duration of a rectifier, characterized by, include: Collect the DC bus voltage and three-phase input current of the rectifier; Determine the first moment when the DC bus voltage is greater than or equal to the first threshold. The first phase input current is defined as the first phase input current when the first phase input current is greater than or equal to the second threshold. The second moment when the first phase input current is greater than or equal to the second threshold is determined. Starting from the second moment, determine the functional relationship between the first phase incoming current and the elapsed time. Based on the aforementioned functional relationship, determine the third moment corresponding to the maximum value of the first phase incoming current; The difference between the third time point and the first time point is used to determine the duration of the main loop closure. Starting from the second moment, determine the functional relationship between the first phase incoming current and the elapsed time, including: Starting from the second moment, determine the effective value of the first phase incoming current within a preset time window; Based on the first phase incoming current at the second moment and the effective value of the first phase incoming current within the preset time window, the functional relationship between the first phase incoming current and the elapsed time is determined; wherein, the functional relationship is an exponential function.

2. The method of claim 1, wherein, The first threshold is determined based on the standard voltage of the rectifier.

3. The method according to claim 1, characterized in that, The second threshold is determined based on the rated current of the rectifier.

4. The method according to claim 1, characterized in that, Based on the aforementioned functional relationship, the third moment corresponding to the maximum value of the first phase incoming current is determined, including: Based on the aforementioned functional relationship, determine the maximum value of the first phase incoming current; Based on the maximum value of the first phase incoming current and the aforementioned functional relationship, the third moment corresponding to the maximum value of the first phase incoming current is determined.

5. The method according to claim 1, characterized in that, Also includes: Compare the determined main loop closure duration with the main loop closure reference duration; The main circuit closure reference duration is determined based on the main circuit closure duration when the rectifier is operating normally; When the deviation between the determined main circuit closing time and the main circuit closing reference time exceeds a preset deviation threshold, a rectifier inspection notification is issued.

6. A device for determining the closing time of the main circuit of a rectifier, characterized in that, include: The signal acquisition module is used to acquire the DC bus voltage and three-phase input current of the rectifier; The first moment determination module is used to determine the first moment when the DC bus voltage is greater than or equal to the first threshold. The second moment determination module is used to determine the first phase incoming current as the first phase incoming current when the first phase incoming current is greater than or equal to the second threshold among the three phase incoming currents, and to determine the second moment when the first phase incoming current is greater than or equal to the second threshold. The function relationship determination module is used to determine the function relationship between the first phase incoming current and the elapsed time, starting from the second time point; The third moment determination module is used to determine the third moment corresponding to the maximum value of the first phase incoming current based on the functional relationship. The closing duration determination module is used to determine the closing duration of the main loop by the difference between the third time point and the first time point. The module for determining function relationships is specifically used for: Starting from the second moment, determine the effective value of the first phase incoming current within a preset time window; Based on the first phase incoming current at the second moment and the effective value of the first phase incoming current within the preset time window, the functional relationship between the first phase incoming current and the elapsed time is determined; wherein, the functional relationship is an exponential function.

7. The apparatus according to claim 6, characterized in that, The first threshold is determined based on the standard voltage of the rectifier.

8. The apparatus according to claim 6, characterized in that, The second threshold is determined based on the rectifier's rated current.

9. The apparatus according to claim 6, characterized in that, The third-moment determination module is specifically used for: Based on the aforementioned functional relationship, determine the maximum value of the first phase incoming current; Based on the maximum value of the first phase incoming current and the aforementioned functional relationship, the third moment corresponding to the maximum value of the first phase incoming current is determined.

10. The apparatus according to claim 6, characterized in that, Also includes: The duration determination module is used to compare the determined main circuit closure duration with the main circuit closure reference duration. The main circuit closure reference duration is determined based on the main circuit closure duration when the rectifier is operating normally; The notification module is used to issue a rectifier check notification when the deviation between the determined main circuit closing time and the main circuit closing reference time is greater than a preset deviation threshold.

11. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 1 to 5.

13. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 1 to 5.

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