Power module pulse test method and equipment for converter

Abstract

This invention discloses a pulse testing method and device for power modules of a converter. It includes: acquiring the target load current, the effective switching state of the power module under test, and the state switching path; determining the target switching state within the effective switching state; determining a first switching path, a second switching path, and a third switching path within the state switching paths; determining the switching frequency of the target switching state and adjacent effective switching states in the third switching path based on the target load current; generating a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment; and generating a control signal based on a preset duty cycle, switching frequency, and pulse test sequence. This method ensures that the outer transistor turns off before the inner transistor, and allows testing of another target power semiconductor immediately after testing the first target power semiconductor, thus improving the testing efficiency of the power module.

Description

Technical Field

[0001] This invention relates to the field of power electronic converter testing technology, and in particular to a power module pulse testing method and equipment for converters. Background Technology

[0002] In multilevel power modules, especially in three-level NPC (Neutral Point Clamped) topologies, the turn-off sequence of power semiconductors is crucial for protecting power devices, preventing overvoltage, and ensuring stable system operation. An incorrect turn-off sequence may cause power devices to withstand excessively high voltages, resulting in damage or failure. Therefore, it is necessary to ensure that the outer transistor turns off before the inner transistor.

[0003] Currently, the double-pulse testing (DPT) method, which involves two switching state cycles, is commonly used to evaluate the switching characteristics of power semiconductors (such as IGBTs and MOSFETs) under different states. However, for safety reasons, this method generally requires power disconnection and rewiring when testing different power semiconductors, resulting in low testing efficiency. Summary of the Invention

[0004] To address the aforementioned problems, the inventors have developed this invention, which, through specific embodiments, provides a method and apparatus for testing the power module pulse of a converter.

[0005] In a first aspect, embodiments of the present invention provide a power module pulse testing method for a converter, comprising:

[0006] The target load current, the effective switching state and state switching path of the power module under test are obtained. The effective switching state includes a quasi-locked state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube.

[0007] Based on the target power semiconductor, determine the target switching state within the effective switching state;

[0008] Based on the target switch state, a first switching path, a second switching path, and a third switching path are determined in the state switching path. The starting switch state and the ending switch state of the first switching path are respectively the quasi-locked switch state and the target switch state. The starting switch state and the ending switch state of the second switching path are respectively the target switch state and the quasi-locked switch state. The third switching path is a cyclic switching path between the target switch state and the adjacent effective switch state.

[0009] Based on the target load current, determine the switching frequency of the target switch state and the adjacent effective switch state in the third switching path;

[0010] A pulse test sequence is generated with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment.

[0011] Based on the preset duty cycle, switching frequency, and pulse test sequence, a control signal is generated and sent to the controller of the power module under test to turn the target power semiconductor and the corresponding power semiconductor off and on.

[0012] Secondly, embodiments of the present invention provide a power module pulse testing device for a converter, comprising:

[0013] The information acquisition module is used to acquire the target load current, the effective switching state and state switching path of the power module under test. The effective switching state includes a quasi-locked state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube.

[0014] A sequence generation module is used to determine a target switching state based on a target power semiconductor within an effective switching state; based on the target switching state, determine a first switching path, a second switching path, and a third switching path within the state switching path, wherein the starting and ending switching states of the first switching path are a quasi-locked switching state and the target switching state, respectively; the starting and ending switching states of the second switching path are the target switching state and the quasi-locked switching state, respectively; and the third switching path is a cyclic switching path between the target switching state and adjacent effective switching states; determine the switching frequency of the target switching state and adjacent effective switching states in the third switching path based on the target load current; and generate a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment.

[0015] The control module generates a control signal based on a preset duty cycle, switching frequency, and the pulse test sequence, and sends the control signal to the controller of the power module under test to turn the target power semiconductor and the corresponding power semiconductor off and on.

[0016] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0017] The system acquires the target load current, the effective switching state of the power module under test, and the state transition path. The effective switching state includes a quasi-locked state. When the switching state of the power module under test before lockout is a quasi-locked switching state, the outer transistor of the power module under test is turned off before the inner transistor. Based on the target power semiconductor, a target switching state is determined within the effective switching states. Based on the target switching state, a first transition path, a second transition path, and a third transition path are determined within the state transition path. The starting and ending switching states of the first transition path are the quasi-locked switching state and the target switching state, respectively. The starting and ending switching states of the second transition path are the target switching state and the quasi-locked switching state, respectively. The three switching paths are mutually cyclic switching paths between the target switching state and the adjacent effective switching state. Based on the target load current, the switching frequency of the target switching state and the adjacent effective switching state in the third switching path is determined. A pulse test sequence is generated with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the tail segment. Based on the preset duty cycle, switching frequency, and the pulse test sequence, a control signal is generated and sent to the controller of the power module under test to turn off and on the target power semiconductor and the corresponding power semiconductor. This ensures that the outer tube turns off before the inner tube, and after the target power semiconductor is tested, another target power semiconductor can be tested, thus improving the testing efficiency of the power module.

[0018] Other features and advantages of the invention will be set forth in the following description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a flowchart of the method in an embodiment of the present invention;

[0022] Figure 2 This is an electrical schematic diagram of the power module in an embodiment of the present invention.

[0023] Figure 3 for Figure 2 The diagram shows the effective switching states and state transition paths of the power module.

[0024] Figure 4for Figure 2 The diagram shows a test circuit schematic for the power module.

[0025] Figure 5 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0026] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0027] As the interface between new energy power generation systems and the power grid, the power module verification is a mandatory testing item in R&D and production to ensure product quality. The efficiency of power module testing and verification directly affects the progress and cost of converter R&D and production.

[0028] With increasingly stringent grid connection guidelines and unit reliability requirements, the use of full-power converters in large-capacity wind turbines is a growing trend, as converters serve as the interface between new energy power generation systems and the grid. The adoption of three-level power modules in converters significantly increases the capacity of a single converter and improves unit reliability. The highest capacity of wind power full-power converters based on integrated gate commutated thyristors (IGCTs) has exceeded 10MW. The use of active neutral-point clamped three-level power modules in converters, compared to traditional passive neutral-point clamped three-level modules, reduces the temperature difference of power semiconductors and significantly improves the power density of the converter.

[0029] The demand for grid connection of new energy sources has also driven the demand for power testing equipment. Commonly used oscilloscopes are typically 4-channel, capable of measuring the voltage across a maximum of three power semiconductors and one load current. Currently, digital oscilloscopes have reached 6-channel and 8-channel versions. An 8-channel oscilloscope can easily test the voltage across six power semiconductors and one load current.

[0030] In multilevel power modules, especially in three-level NPC (Neutral Point Clamped) topologies, the turn-off sequence of power semiconductors is crucial for protecting power devices, preventing overvoltage, and ensuring stable system operation. An incorrect turn-off sequence may cause power devices to withstand excessively high voltages, resulting in damage or failure. Therefore, it is necessary to ensure that the outer transistor turns off before the inner transistor.

[0031] Currently, the double-pulse testing (DPT) method, which involves two switching state cycles, is commonly used to evaluate the switching characteristics of power semiconductors (such as IGBTs and MOSFETs) under different states. However, for safety reasons, this method generally requires power disconnection and rewiring when testing different power semiconductors, resulting in low testing efficiency.

[0032] To address the problems existing in the prior art, embodiments of the present invention provide a power module pulse testing method and device for a converter.

[0033] This invention provides a method for testing the power module pulse of a converter, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0034] Step S10: Obtain the target load current, the effective switching state of the power module under test, and the state switching path. The effective switching state includes a quasi-locked state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube.

[0035] Among them, the target load current corresponds to the target power semiconductor. The effective switching state of the power module under test is determined according to its topology. The quasi-locked state is an effective switching state that ensures that the outer tube is turned off before the inner tube before the power unit is locked. The state switching path is the process by which the internal switching elements (such as IGBT, MOSFET, etc.) of the converter switch from one on-off combination state to another on-off combination state during the operation of the converter.

[0036]

[0037] Table 1

[0038] For example, the power module under test is an active neutral-point clamped three-level power module, and its electrical principle is as follows: Figure 2 As shown, the target power semiconductor includes T1 to T6, where T1 and T4 are outer transistors, and T2 and T3 are inner transistors; the state switching path is as follows: Figure 3 As shown in Table 1, the effective switching states of the power module under test include switch state P, switch state OU1, switch state OU2, switch state OL1, switch state OL2 and switch state N. Among them, the quasi-locked switching states include switch state OL1 and switch state OU1. When the switch state of the power module under test before being locked is switch state OL1 or switch state OU1, the outer tube of the power module under test is turned off before the inner tube, that is, T1 and T4 are turned off before T2 and T3.

[0039] Step S20: Based on the target power semiconductor, determine the target switching state in the effective switching state.

[0040] The target power semiconductor may include one or more power semiconductors, and the target switching state is a switching state that can change the on / off state of the target power semiconductor when a switching state switch occurs.

[0041] For example, the target power semiconductor can be any power semiconductor from T1 to T6, or a combination of T1 to T6. For instance, the target switching state corresponding to T1 can be switching state P.

[0042] Step S30: Based on the target switch state, determine a first switching path, a second switching path, and a third switching path in the state switching path, wherein the starting switch state and the ending switch state of the first switching path are the quasi-locked switch state and the target switch state, respectively; the starting switch state and the ending switch state of the second switching path are the target switch state and the quasi-locked switch state, respectively; and the third switching path is a cyclic switching path between the target switch state and the adjacent effective switch state.

[0043] For example, such as Figure 3 As shown, taking switch state P as an example, the first switching path can be from switch state OU1 to switch state P, the second path can be a cyclic switching path between switch state P and switch state OU1, and the third path can be from switch state P to switch state OU1.

[0044] Step S40: Based on the target load current, determine the switching frequency of the target switch state and the adjacent effective switch state in the third switching path.

[0045] The adjacent active switch state is the switch state that is adjacent to the target switch state in the state switching path. During testing, the target switch state and the adjacent active switch state need to be switched cyclically to increase the inductor current to the target load current.

[0046] For example, in the above-mentioned active neutral point clamped three-level power module, when the target switch state is switch state P, the adjacent effective switch state is switch state OU1 or switch state OL1.

[0047] Step S50: Generate a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment.

[0048] Step S60: Based on the preset duty cycle, switching frequency and the pulse test sequence, generate a control signal and send the control signal to the controller of the power module under test so as to turn off and on the target power semiconductor and the corresponding power semiconductor.

[0049] In the above method of this embodiment, the second switching path is the state switching path with the shortest path, where the starting switch state and the ending switch state are the target switch state and the quasi-locked switch state, respectively.

[0050] The path distance is calculated based on the number of switch state transitions; that is, the fewer the number of switch state transitions, the shorter the state transition path.

[0051] Understandably, the shorter the second switching path, the shorter the generated pulse test sequence, which can further improve testing efficiency.

[0052] In the above method of this embodiment, the control signal is generated based on the preset duty cycle, switching frequency and the pulse test sequence, including the following steps: when multiple pulse test sequences are generated, the target pulse test sequence is determined based on the number of switching states in the pulse test sequence;

[0053] The process of generating a control signal based on a preset duty cycle, switching frequency, and pulse test sequence includes the following steps: generating a control signal based on a preset duty cycle, switching frequency, and target pulse test sequence.

[0054] For example, as shown in Table 2, after the sequence 1 test is completed, if the target power semiconductor is T3, the generated pulse test sequence includes sequence 2 and sequence 3. The number of on-states in sequence 3 is greater than that in sequence 2, so sequence 3 is determined as the target pulse test sequence.

[0055] Serial number Level state sequence Target power semiconductor 1 <![CDATA[Lock - OU1 - P - [OU1 - P] n - OU1 - Lock]]> <![CDATA[T1 / T2 / T5 / T6]]> 2 <![CDATA[Lock - OL1 - N - [OL1 - N] n - OL1 - Lock]]> <![CDATA[T3 / T4 / T5 / T6]]> 3 <![CDATA[Lock - OU1 - P - OL2 -> [P - OL2] n - OL1 - Lock]]> <![CDATA[T1 / T3 / T6]]> 4 <![CDATA[Lock - OL1 - N - OU2 - [N - OU2] n - OU1 - Lock]]> <![CDATA[T2 / T4 / T5]]>

[0056] Table 2

[0057] Among them, [OU1-P] n This indicates that the two switch states (OU1 and P) cycle n times, where n is an integer.

[0058] The method described in this embodiment further includes the following steps:

[0059] Receive the test current and test voltage sent by the oscilloscope; based on the test current and test voltage, output the test results of the target power semiconductor.

[0060] The method described in this embodiment further includes the following steps:

[0061] Based on the test results, the accuracy of the test results is determined.

[0062] The method described in this embodiment obtains the target load current, the effective switching state of the power module under test, and the state switching path; based on the target power semiconductor, it determines the target switching state within the effective switching state; based on the target switching state, it determines a first switching path, a second switching path, and a third switching path within the state switching path; based on the target load current, it determines the switching frequency of the target switching state and adjacent effective switching states in the third switching path; it generates a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the tail segment; based on a preset duty cycle, switching frequency, and the pulse test sequence, it generates a control signal and sends the control signal to the controller of the power module under test, so as to turn off and on the target power semiconductor and the corresponding power semiconductor, ensuring that the outer tube turns off before the inner tube, and that after the target power semiconductor is tested, another target power semiconductor can be tested, thus improving the testing efficiency of the power module.

[0063] For example, the power module under test is an active neutral-point clamped three-level power module, the oscilloscope is a 6-channel or 8-channel oscilloscope, and the inductor is as follows: Figure 4 As shown in the diagram, the multiple channels of the oscilloscope are connected to T1 to T6 respectively. The power module pulse test method of the converter in this embodiment is used to perform pulse test on the power module under test. This method enables the outer tube of the three-level power module to be turned off before the inner tube. It tests the switching characteristics of the power semiconductor under various commutation conditions without changing the inductor connection position, minimizes the use of oscilloscope channels, improves test efficiency, and reduces test costs.

[0064] Those skilled in the art can change the above order without departing from the scope of protection of this disclosure.

[0065] Another embodiment of the present invention provides a power module pulse testing device for a converter, comprising:

[0066] The information acquisition module is used to acquire the target load current, the effective switching state and state switching path of the power module under test. The effective switching state includes a quasi-locked state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube.

[0067] A sequence generation module is used to determine a target switching state based on a target power semiconductor within an effective switching state; based on the target switching state, determine a first switching path, a second switching path, and a third switching path within the state switching path, wherein the starting and ending switching states of the first switching path are a quasi-locked switching state and the target switching state, respectively; the starting and ending switching states of the second switching path are the target switching state and the quasi-locked switching state, respectively; and the third switching path is a cyclic switching path between the target switching state and adjacent effective switching states; determine the switching frequency of the target switching state and adjacent effective switching states in the third switching path based on the target load current; and generate a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment.

[0068] The control module generates a control signal based on a preset duty cycle, switching frequency, and the pulse test sequence, and sends the control signal to the controller of the power module under test to turn the target power semiconductor and the corresponding power semiconductor off and on.

[0069] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0070] In this embodiment, the device further includes,

[0071] The information feedback module is used to receive the test current and test voltage sent by the oscilloscope; based on the test current and test voltage, it outputs the test results of the target power semiconductor.

[0072] In this embodiment, the device further includes,

[0073] The judgment module is used to judge the accuracy of the test results based on the test results.

[0074] Based on the same inventive concept, embodiments of the present invention also provide an electronic device, the structure of which is as follows: Figure 5 As shown, it includes: a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the aforementioned power module pulse test method for the converter.

[0075] Based on the same inventive concept, embodiments of the present invention also provide a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the aforementioned power module pulse testing method for a converter.

[0076] Any modifications, additions, and equivalent substitutions made within the scope of the principles of this invention shall still fall within the patent coverage of this invention.

[0077] Unless otherwise stated, the term "connection" as used above refers to a logical relationship of current transmission and does not necessarily indicate a direct electrical connection. Furthermore, terms such as "first" and "second" do not indicate a sequential order but are merely used to identify related units or devices.

[0078] The present invention is not limited to the voltage levels described above; the voltage levels described above are merely voltage levels used in the embodiments.

Claims

1. A pulse test method for the power module of a converter, characterized in that, Includes the following steps: The target load current, the effective switching state of the power module under test, and the state switching path are obtained. The effective switching state includes a quasi-locked switching state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube. The quasi-locked switching state is an effective switching state that ensures that the outer tube of the power module under test is turned off before the inner tube before being locked. Based on the target power semiconductor, determine the target switching state in the effective switching state; Based on the target switch state, a first switching path, a second switching path, and a third switching path are determined in the state switching path. The starting and ending switch states of the first switching path are the quasi-locked switch state and the target switch state, respectively. The starting and ending switch states of the second switching path are the target switch state and the quasi-locked switch state, respectively. The third switching path is a cyclic switching path between the target switch state and adjacent valid switch states. The adjacent valid switch state is the switch state adjacent to the target switch state in the state switching path. Based on the target load current, determine the switching frequency of the target switch state and the adjacent effective switch state in the third switching path; A pulse test sequence is generated with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the last segment. Based on the preset duty cycle, switching frequency, and pulse test sequence, a control signal is generated and sent to the controller of the power module under test to turn the target power semiconductor and the corresponding power semiconductor off and on.

2. The method as described in claim 1, characterized in that, The second switching path is the state switching path with the starting switch state and the ending switch state being the target switch state and the quasi-locked switch state, respectively, and the path being the shortest.

3. The method as described in claim 2, characterized in that, The process of generating a control signal based on a preset duty cycle, switching frequency, and pulse test sequence includes the following steps: When multiple pulse test sequences are generated, the target pulse test sequence is determined based on the number of switching states in the pulse test sequences. The process of generating a control signal based on a preset duty cycle, switching frequency, and pulse test sequence includes the following steps: generating a control signal based on a preset duty cycle, switching frequency, and target pulse test sequence.

4. The method as described in claim 1, characterized in that, It also includes the following steps: Receive the test current and test voltage sent by the oscilloscope; based on the test current and test voltage, output the test results of the target power semiconductor.

5. The method as described in claim 4, characterized in that, It also includes the following steps: Based on the test results, the accuracy of the test results is determined.

6. A power module pulse testing device for a converter, characterized in that, include: The information acquisition module is used to acquire the target load current, the effective switching state of the power module under test, and the state switching path. The effective switching state includes a quasi-locked switching state. When the switching state of the power module under test before being locked is a quasi-locked switching state, the outer tube of the power module under test is turned off before the inner tube. The quasi-locked switching state is an effective switching state that ensures that the outer tube of the power module under test is turned off before the inner tube before being locked. A sequence generation module is used to determine a target switching state based on a target power semiconductor within an effective switching state; based on the target switching state, determine a first switching path, a second switching path, and a third switching path within the state switching path, wherein the starting and ending switching states of the first switching path are a quasi-locked switching state and the target switching state, respectively; the starting and ending switching states of the second switching path are the target switching state and the quasi-locked switching state, respectively; and the third switching path is a cyclic switching path between the target switching state and adjacent effective switching states; determine the switching frequency of the target switching state and adjacent effective switching states in the third switching path based on the target load current; and generate a pulse test sequence with the first switching path as the first segment, the third switching path as the middle segment, and the second switching path as the tail segment; the adjacent effective switching state is the switching state adjacent to the target switching state within the state switching path. The control module generates a control signal based on a preset duty cycle, switching frequency, and the pulse test sequence, and sends the control signal to the controller of the power module under test to turn the target power semiconductor and the corresponding power semiconductor off and on.

7. The apparatus as claimed in claim 6, characterized in that, It also includes an information feedback module for receiving test current and test voltage sent by the oscilloscope; and outputting the test results of the target power semiconductor based on the test current and test voltage.

8. The apparatus as claimed in claim 7, characterized in that, It also includes a judgment module, used to judge the accuracy of the test results based on the test results.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the computer program, implements the power module pulse test method for the converter according to any one of claims 1 to 5.

10. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when executed, implement the power module pulse test method for the converter according to any one of claims 1 to 5.

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