Method and system for testing self-healing performance of direct-current support capacitor

Abstract

The invention discloses a method and system for testing the self-healing performance of a direct-current support capacitor, and the method comprises the steps: determining a testing system for testing the self-healing performance of the direct-current support capacitor; on the basis of the test system, a direct-current power supply charges between terminals of a to-be-tested direct-current support capacitor, and the charging current is controlled to increase the direct-current voltage between the terminals of the to-be-tested direct-current support capacitor according to a certain step; monitoring whether the direct-current support capacitor to be detected is self-healed or not through an ultrasonic probe in each voltage step time; and discharging between the terminals of the direct current support capacitor to be tested through the energy discharge resistor, so that the voltage between the terminals of the direct current support capacitor is reduced to zero. Therefore, the direct-current power supply is utilized to apply a certain step of direct-current voltage between the terminals of the direct-current support capacitor for charging, the self-healing energy of the direct-current support capacitor is measured under the test condition, and the self-healing performance is judged.

Description

Technical Field

[0001] The present invention relates to the technical field of power detection, and more specifically, to a method and system for testing the self-healing performance of a DC support capacitor. Background Art

[0002] DC support capacitors, also known as DC-link capacitors, are used in flexible DC transmission to absorb high-amplitude pulsating currents from the inverter to the DC-Link, preventing it from generating high-amplitude pulsating voltages on the impedance of the DC-Link, keeping the power supply voltage fluctuations at the inverter end within the allowable range; at the same time, preventing the voltage overshoot and transient overvoltage from the DC-Link from affecting the inverter. In recent years, high-voltage self-healing capacitors using metallized films have been widely used in DC-link applications due to their superior electrical properties.

[0003] The main difference between high-voltage self-healing capacitors and conventional full-film capacitors is that their electrodes are very thin. The thin metallized electrodes give them self-healing properties. High-voltage self-healing capacitors use organic thin films as energy storage media. Since the film inevitably has defects or impurities during the production process, the dielectric strength of these areas is lower than that of the surrounding areas. These areas are called electrical weak points.

[0004] As the applied voltage increases, the film at the weak point will first break down, forming a short circuit point. Other intact components connected in parallel with the faulty component and the energy stored in the faulty component itself will be discharged through the breakdown point, forming a discharge channel. Since the electrodes of high-voltage self-healing capacitors are very thin, the short-circuit breakdown current causes local high temperatures, causing the thin metal layer at the breakdown point to evaporate rapidly, diffuse outward, and restore insulation. Therefore, local breakdown will not affect the entire capacitor. This process is called "self-healing" (such as Figure 1 The self-healing characteristics of high-voltage self-healing capacitors largely prevent capacitor failure caused by single weak point breakdown, greatly extending the service life of the capacitor.

[0005] In the design of high-voltage self-healing capacitors, self-healing performance is an important technical indicator. It is closely related to the structural type of metallized electrodes, the composition of materials and the working voltage of components. Whether it has good self-healing performance is the key to the reliable operation of high-voltage self-healing capacitors. At present, the self-healing performance of DC support capacitors is generally detected by applying voltage to detect current, which has poor sensitivity and can only detect whether the capacitor element has self-healing ability, but cannot judge the quality of self-healing performance. Summary of the invention

[0006] According to the present invention, a method and system for testing the self-healing performance of a DC support capacitor are provided to solve the technical problem that the self-healing performance of a DC support capacitor is generally detected by applying voltage to detect current, which has poor sensitivity and can only detect whether the capacitor element has self-healing ability, but cannot judge the quality of the self-healing performance.

[0007] According to a first aspect of the present invention, a method for testing the self-healing performance of a DC support capacitor is provided, comprising:

[0008] Determine the test system for testing the self-healing performance of DC support capacitors;

[0009] Based on the test system, the DC support capacitor terminals to be tested are charged by a DC power supply, and the charging current is controlled so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step;

[0010] During each voltage step time, an ultrasonic probe is used to monitor whether the DC support capacitor to be tested is self-healing;

[0011] The terminals of the DC support capacitor to be tested are discharged through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

[0012] Optionally, a test system for verifying the self-healing performance of the DC support capacitor is determined, including:

[0013] The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device;

[0014] Calibrate the trigger value of the ultrasonic partial discharge measurement device before the test.

[0015] Optionally, it also includes:

[0016] The DC support capacitor to be tested is placed in an oven and heated until the entire body temperature reaches a predetermined temperature.

[0017] Optionally, it also includes:

[0018] The trigger value of the ultrasonic partial discharge measuring device is increased so that the ultrasonic partial discharge measuring device does not detect a trigger signal when no pressure is applied.

[0019] Optionally, based on the test system, charging between the terminals of the DC support capacitor to be tested through a DC power supply, and controlling the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases in a certain step, including:

[0020] Applying a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measuring a first self-healing number of times by using an ultrasonic probe;

[0021] applying a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measuring a second self-healing number by using an ultrasonic probe;

[0022] If the number of self-healing events during this period is less than the predetermined number, the voltage is slowly increased until the predetermined number of self-healing events occur from the start of the test, and the voltage value at this time is recorded, or until the voltage reaches the predetermined voltage. If the number of self-healing events that occur is still less than the predetermined number when the voltage reaches the predetermined voltage, and the test time exceeds the second predetermined time, the test ends.

[0023] According to another aspect of the present invention, a system for testing the self-healing performance of a DC support capacitor is provided, comprising:

[0024] Determine the test system module, which is used to determine the test system for testing the self-healing performance of the DC support capacitor;

[0025] A capacitor charging module is used to charge the terminals of the DC support capacitor to be tested through a DC power supply based on the test system, and control the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step;

[0026] A capacitor monitoring module is used to monitor whether the DC support capacitor to be tested has self-healed by using an ultrasonic probe during each voltage step time;

[0027] The capacitor discharge module is used to discharge the terminals of the DC support capacitor to be tested through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

[0028] Optionally, determine the test system modules, including:

[0029] The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device;

[0030] The trigger value correction submodule is used to correct the trigger value of the ultrasonic partial discharge measurement device before the test.

[0031] Optionally, it also includes:

[0032] The heating oven module is used to place the DC support capacitor to be tested in an oven for heating until the entire body temperature reaches a predetermined temperature.

[0033] Optionally, it also includes:

[0034] The trigger value correction module is used to increase the trigger value of the ultrasonic partial discharge measurement device so that the ultrasonic partial discharge measurement device does not detect the trigger signal when no pressure is applied.

[0035] Optionally, a capacitor charging module,

[0036] A first self-healing times measuring submodule, configured to apply a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measure a first self-healing times by means of an ultrasonic probe;

[0037] A submodule for measuring a second self-healing number is used to apply a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measure a second self-healing number through an ultrasonic probe;

[0038] The voltage value recording submodule is used to slowly increase the voltage until the predetermined number of self-healings occur from the start of the test, and record the voltage value at this time, or until the voltage reaches the predetermined voltage. If the number of self-healings that occur during this period is less than the predetermined number, and the test time exceeds the second predetermined time, the test ends.

[0039] Therefore, a DC power supply is used to apply a DC voltage of a certain step between the terminals of the DC support capacitor for charging, so as to measure the self-healing energy of the DC support capacitor under test conditions and judge the quality of the self-healing performance. This solves the problem that the current method of detecting the self-healing performance of the DC support capacitor by applying voltage to detect current has poor sensitivity and can only detect whether the capacitor element has the self-healing ability, but cannot judge the quality of the self-healing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0041] Figure 1 A schematic diagram of the self-healing of a high-voltage self-healing capacitor according to this embodiment;

[0042] Figure 2 A schematic diagram of a method for testing the self-healing performance of a DC support capacitor according to this embodiment;

[0043] Figure 3 This is a schematic diagram of the principle of the self-healing performance testing method of the DC support capacitor according to this embodiment;

[0044] Figure 4 Schematic diagram of a system for testing the self-healing performance of a DC support capacitor according to this embodiment. DETAILED DESCRIPTION

[0045] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0046] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0047] According to a first aspect of the present invention, a method 200 for testing the self-healing performance of a DC support capacitor is provided. Figure 2 As shown, the method 200 includes:

[0048] S201: Determine a test system for testing the self-healing performance of DC support capacitors;

[0049] S202: Based on the test system, charging the terminals of the DC support capacitor to be tested through a DC power supply, and controlling the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step;

[0050] S203: monitoring whether the DC support capacitor to be tested is self-healing by using an ultrasonic probe during each voltage step time;

[0051] S204: Discharge between the terminals of the DC support capacitor to be tested through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

[0052] Specifically, refer to Figure 3 As shown, a DC power supply is used to apply a certain step of DC voltage between the terminals of the DC support capacitor for charging, so as to measure the self-healing energy of the DC support capacitor under test conditions and judge the self-healing performance, so as to improve and optimize the design parameters and enhance the operational reliability of the product. The specific contents are as follows:

[0053] The DC power supply is used to charge the terminals of the DC support capacitor of the test object, and the charging current is controlled to increase the DC voltage between the capacitor terminals in a certain step. During each voltage step time, the ultrasonic probe is used to monitor whether the capacitor is self-healing. Then, the capacitor terminals are discharged through the energy dissipation resistor to reduce the voltage between the capacitor terminals to 0. Figure 2 Describe the implementation method.

[0054] The test system consists of 1-DC power supply, 2-power electronic rectifier, 3-protection resistor, 4-test capacitor, 5-ultrasonic probe, 6-discharge resistor, 7-grounding, and 8-ultrasonic partial discharge measuring device. In order to ensure that the self-healing discharge between the 4 terminals of the tested capacitor can be correctly and effectively detected, the trigger value of the ultrasonic partial discharge measuring device 8 should be calibrated before the test. The specific test method is as follows:

[0055] The capacitor 4 under test is placed in an oven and heated until the whole body temperature reaches 70°C;

[0056] According to the principle diagram of the DC support capacitor self-healing performance test method, the various parts of the circuit are connected. First, the trigger value of the ultrasonic partial discharge measuring device 8 is increased from 0 so that the ultrasonic partial discharge measuring device 8 does not detect the trigger signal when no pressure is applied.

[0057] Apply 1.1U between the test sample terminals. NDC (rated DC voltage) for 30 seconds, and the number of self-healing times was measured using an ultrasonic probe;

[0058] Apply 1.25U between the terminals of the test capacitor. NDC A DC voltage of 10 s was applied, and the number of self-healing times was measured using an ultrasonic probe.

[0059] If the self-healing occurs less than 5 times during this period, the voltage should be slowly increased until 5 self-healings occur from the start of the test, and the voltage value at this time should be recorded, or until the voltage reaches 2.5U NDC If the voltage reaches 2.5U NDC When the self-healing occurs less than 5 times and the test time exceeds 10s, the test ends.

[0060] The self-healing performance of the tested capacitor 4 under the test conditions can be obtained through the above test method.

[0061] Therefore, a DC power supply is used to apply a DC voltage of a certain step between the terminals of the DC support capacitor for charging, so that the self-healing energy of the DC support capacitor can be measured under test conditions, and the self-healing performance can be judged to improve and optimize the design parameters and enhance the operational reliability of the product.

[0062] Optionally, a test system for verifying the self-healing performance of the DC support capacitor is determined, including:

[0063] The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device;

[0064] Calibrate the trigger value of the ultrasonic partial discharge measurement device before the test.

[0065] Optionally, it also includes:

[0066] The DC support capacitor to be tested is placed in an oven and heated until the entire body temperature reaches a predetermined temperature.

[0067] Optionally, it also includes:

[0068] The trigger value of the ultrasonic partial discharge measuring device is increased so that the ultrasonic partial discharge measuring device does not detect a trigger signal when no pressure is applied.

[0069] Optionally, based on the test system, charging between the terminals of the DC support capacitor to be tested through a DC power supply, and controlling the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases in a certain step, including:

[0070] Applying a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measuring a first self-healing number of times by using an ultrasonic probe;

[0071] applying a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measuring a second self-healing number by using an ultrasonic probe;

[0072] If the number of self-healing events during this period is less than the predetermined number, the voltage is slowly increased until the predetermined number of self-healing events occur from the start of the test, and the voltage value at this time is recorded, or until the voltage reaches the predetermined voltage. If the number of self-healing events that occur is still less than the predetermined number when the voltage reaches the predetermined voltage, and the test time exceeds the second predetermined time, the test ends.

[0073] Therefore, a DC power supply is used to apply a DC voltage of a certain step between the terminals of the DC support capacitor for charging, so as to measure the self-healing energy of the DC support capacitor under test conditions and judge the quality of the self-healing performance. This solves the problem that the current method of detecting the self-healing performance of the DC support capacitor by applying voltage to detect current has poor sensitivity and can only detect whether the capacitor element has the self-healing ability, but cannot judge the quality of the self-healing performance.

[0074] According to another aspect of the present invention, a system 400 for testing the self-healing performance of a DC support capacitor is provided. Figure 4 As shown, the system 400 includes:

[0075] Determine a test system module 410, for determining a test system for testing the self-healing performance of the DC support capacitor;

[0076] The capacitor charging module 420 is used to charge the terminals of the DC support capacitor to be tested through a DC power supply based on the test system, and control the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step;

[0077] The capacitor monitoring module 430 is used to monitor whether the DC support capacitor to be tested is self-healing by using an ultrasonic probe during each voltage step time;

[0078] The capacitor discharging module 440 is used to discharge the voltage between the terminals of the DC support capacitor to be tested through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

[0079] Optionally, determine the test system modules, including:

[0080] The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device;

[0081] The trigger value correction submodule is used to correct the trigger value of the ultrasonic partial discharge measurement device before the test.

[0082] Optionally, it also includes:

[0083] The heating oven module is used to place the DC support capacitor to be tested in an oven for heating until the entire body temperature reaches a predetermined temperature.

[0084] Optionally, it also includes:

[0085] The trigger value correction module is used to increase the trigger value of the ultrasonic partial discharge measurement device so that the ultrasonic partial discharge measurement device does not detect the trigger signal when no pressure is applied.

[0086] Optionally, a capacitor charging module,

[0087] A first self-healing times measuring submodule, configured to apply a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measure a first self-healing times by means of an ultrasonic probe;

[0088] A submodule for measuring a second self-healing number is used to apply a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measure a second self-healing number through an ultrasonic probe;

[0089] The voltage value recording submodule is used to slowly increase the voltage until the predetermined number of self-healings occur from the start of the test, and record the voltage value at this time, or until the voltage reaches the predetermined voltage. If the number of self-healings that occur during this period is less than the predetermined number, and the test time exceeds the second predetermined time, the test ends.

[0090] A system 400 for testing the self-healing performance of a DC support capacitor according to an embodiment of the present invention corresponds to a method 100 for testing the self-healing performance of a DC support capacitor according to another embodiment of the present invention, and will not be described in detail herein.

[0091] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0092] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0093] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0095] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0096] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for testing the self-healing performance of a DC support capacitor, characterized in that: include: Determine the test system for testing the self-healing performance of DC support capacitors; Based on the test system, the DC support capacitor terminals to be tested are charged by a DC power supply, and the charging current is controlled so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step; During each voltage step time, an ultrasonic probe is used to monitor whether the DC support capacitor to be tested is self-healing; The terminals of the DC support capacitor to be tested are discharged through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

2. The method according to claim 1, characterized in that The test system for testing the self-healing performance of DC support capacitors includes: The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device; Calibrate the trigger value of the ultrasonic partial discharge measurement device before the test.

3. The method according to claim 2, characterized in that Also includes: The DC support capacitor to be tested is placed in an oven and heated until the entire body temperature reaches a predetermined temperature.

4. The method according to claim 3, characterized in that Also includes: The trigger value of the ultrasonic partial discharge measuring device is increased so that the ultrasonic partial discharge measuring device does not detect a trigger signal when no pressure is applied.

5. The method according to claim 4, characterized in that Based on the test system, the DC support capacitor terminals to be tested are charged by a DC power supply, and the charging current is controlled so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step, including: Applying a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measuring a first self-healing number of times by using an ultrasonic probe; applying a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measuring a second self-healing number by using an ultrasonic probe; If the number of self-healing events during this period is less than the predetermined number, the voltage is slowly increased until the predetermined number of self-healing events occur from the start of the test, and the voltage value at this time is recorded, or until the voltage reaches the predetermined voltage. If the number of self-healing events that occur is still less than the predetermined number when the voltage reaches the predetermined voltage, and the test time exceeds the second predetermined time, the test ends.

6. A test system for the self-healing performance of a DC support capacitor, characterized in that: include: Determine the test system module, which is used to determine the test system for testing the self-healing performance of the DC support capacitor; A capacitor charging module is used to charge the terminals of the DC support capacitor to be tested through a DC power supply based on the test system, and control the charging current so that the DC voltage between the terminals of the DC support capacitor to be tested increases according to a certain step; A capacitor monitoring module is used to monitor whether the DC support capacitor to be tested has self-healed by using an ultrasonic probe during each voltage step time; The capacitor discharge module is used to discharge the terminals of the DC support capacitor to be tested through the energy dissipation resistor, so that the voltage between the terminals of the DC support capacitor drops to zero.

7. The system according to claim 6, characterized in that Determine the test system modules, including: The test system includes a DC power supply, a power electronic rectifier device, a protective resistor, a DC support capacitor to be tested, an ultrasonic probe, a discharge resistor, a grounding device, and an ultrasonic partial discharge measuring device; The trigger value correction submodule is used to correct the trigger value of the ultrasonic partial discharge measurement device before the test.

8. The system according to claim 7, characterized in that Also includes: The heating oven module is used to place the DC support capacitor to be tested in an oven for heating until the entire body temperature reaches a predetermined temperature.

9. The system according to claim 8, characterized in that Also includes: The trigger value correction module is used to increase the trigger value of the ultrasonic partial discharge measurement device so that the ultrasonic partial discharge measurement device does not detect the trigger signal when no pressure is applied.

10. The system according to claim 6, characterized in that Capacitor charging module, A first self-healing times measuring submodule, configured to apply a DC voltage of a first rated DC voltage between the terminals of the DC support capacitor to be tested for a first predetermined time, and measure a first self-healing times by means of an ultrasonic probe; A submodule for measuring a second self-healing number is used to apply a DC voltage of a second rated DC voltage between the terminals of the DC support capacitor to be tested for a second predetermined time, and measure a second self-healing number through an ultrasonic probe; The voltage value recording submodule is used to slowly increase the voltage until the predetermined number of self-healings occur from the start of the test, and record the voltage value at this time, or until the voltage reaches the predetermined voltage. If the number of self-healings that occur during this period is less than the predetermined number, and the test time exceeds the second predetermined time, the test ends.

Images