Test method, master control system, test device and test system of common mode inductor

Abstract

This application provides a testing method, main control system, testing device, and testing system for common-mode inductors. By short-circuiting the first terminals of coils with different phase numbers, the distribution patterns of differential-mode current are simulated, thus covering various operating scenarios. Subsequently, the reference inductance measured by the testing instrument is obtained when the DC source output current is zero. With the reference current meeting preset requirements, the operating inductance measured by the testing instrument is obtained when the DC source output current is the operating differential-mode current. By controlling the DC source output differential-mode current and combining it with the inductance measurement of the testing instrument, the attenuation rate of the common-mode inductance is calculated. This overcomes the limitations of existing technologies for static single-phase testing, enabling a comprehensive evaluation of the common-mode inductance attenuation characteristics under real differential-mode current conditions.

Description

Technical Field

[0001] This application relates to the field of inductance measurement, and more particularly to a test method, main control system, test device and test system for common mode inductors. Background Technology

[0002] In new energy vehicles, the common-mode inductor is a core component for improving the product's EMC (Electromagnetic Compatibility). The performance of the common-mode inductor directly affects the stability of the equipment in complex electromagnetic environments.

[0003] Testing common-mode inductance is crucial for verifying whether a common-mode inductor can maintain its performance. However, existing testing methods only measure the inductance of a single phase under static conditions, lacking testing under dynamic differential-mode current, and therefore cannot comprehensively evaluate its performance stability in actual operation. Summary of the Invention

[0004] The common-mode inductor testing method, main control system, testing device, and testing system provided in this application are used to achieve a comprehensive evaluation of the common-mode inductance attenuation characteristics of a common-mode inductor under real differential-mode current conditions.

[0005] In a first aspect, embodiments of this application provide a method for testing a common-mode inductor, wherein the first ends of at least two phase coils forming a target differential-mode current in the common-mode inductor are short-circuited, a DC source is connected to the second ends of the at least two phase coils, and a testing instrument is connected to the two ends of at least one phase coil. The method includes:

[0006] The reference inductance measured by the test instrument when the DC source output current is zero;

[0007] When the reference inductance meets the preset requirements, the working inductance measured by the test instrument is obtained when the DC source output current is the working differential mode current.

[0008] Based on the reference inductance and the operating inductance, the inductance decay rate of the common-mode inductor under the operating differential-mode current is determined, and the inductance decay rate is used to characterize the performance of the common-mode inductor.

[0009] Optionally, the reference sensitivity and the operating sensitivity include sensitivity at multiple test frequencies;

[0010] The step of determining the inductance attenuation rate of the common-mode inductor under the operating differential-mode current based on the reference inductance and the operating inductance includes:

[0011] Based on the reference sensitivity and operating sensitivity at each test frequency, determine the sensitivity attenuation rate at each test frequency.

[0012] Optionally, the method further includes:

[0013] When the inductance attenuation rate is less than a preset attenuation rate threshold, it is determined that the performance of the common mode inductor is in a stable state.

[0014] When the inductance attenuation rate is greater than or equal to the preset attenuation rate threshold, it is determined that the performance of the common-mode inductor is in an unstable state.

[0015] Optionally, the method further includes:

[0016] In response to user-inputted test commands, determine the current test status;

[0017] Based on the test conditions, determine the range of output current variation of the DC source;

[0018] The operating differential mode current is determined based on the current variation range.

[0019] Secondly, this application provides a main control system, including: a memory and a processor;

[0020] The memory stores computer-executed instructions;

[0021] The processor executes computer execution instructions stored in the memory, causing the processor to perform the method described in the first aspect.

[0022] Thirdly, this application provides a common-mode inductor testing device, including the main control system, DC source, and testing instruments described in the second aspect;

[0023] The main control system is connected to the DC power source and the test instrument;

[0024] The DC source is connected to the second ends of at least two phase coils of the common-mode inductor, the test instrument is connected to the two ends of at least one phase coil of the common-mode inductor, and the first ends of at least two phase coils of the common-mode inductor that form the target differential-mode current are short-circuited.

[0025] Optionally, the testing apparatus for the common-mode inductor further includes:

[0026] An AC power source is provided, which is connected to the main control system, the testing instrument, and the DC power source, respectively.

[0027] An AC / DC isolation circuit is installed between the test instrument and the DC source to isolate AC signals and DC signals.

[0028] Optionally, the testing apparatus for the common-mode inductor further includes:

[0029] An AC / DC isolation circuit is installed between the test instrument and the DC source to isolate AC signals and DC signals.

[0030] Optionally, the DC source includes at least two DC source slaves;

[0031] And / or, the testing instrument includes an LCR meter.

[0032] Fourthly, this application provides a common-mode inductor testing system, including the common-mode inductor testing device described in the third aspect, and a test fixture;

[0033] The test fixture is used to hold the common-mode inductor and short-circuit the first ends of at least two phase coils that form the target differential-mode current in the common-mode inductor according to the test conditions.

[0034] Fifthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method described in the first aspect.

[0035] In a sixth aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0036] The common-mode inductor testing method, main control system, common-mode inductor testing device, and testing system provided in this application simulate the differential-mode current distribution pattern by short-circuiting the first terminals of coils with different phase numbers, thereby covering various working scenarios. Subsequently, the reference inductance measured by the testing instrument is obtained when the DC source output current is zero; and the operating inductance measured by the testing instrument is obtained when the DC source output current is the operating differential-mode current, provided the reference current meets preset requirements. By controlling the DC source output differential-mode current and combining it with the inductance measurement of the testing instrument, the attenuation rate of the common-mode inductance is calculated, thereby overcoming the limitations of existing technologies for static single-phase testing and achieving a comprehensive evaluation of the common-mode inductance attenuation characteristics under real differential-mode current conditions. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0038] Figure 1 This is a schematic diagram of a sensitivity test;

[0039] Figure 2 This is a schematic diagram of another sensitivity test;

[0040] Figure 3A schematic diagram of the common-mode inductor provided in this application;

[0041] Figure 4 Schematic diagram of the common mode inductor and device provided in this application Figure 1 ;

[0042] Figure 5 Schematic diagram of the common mode inductor and device provided in this application Figure 2 ;

[0043] Figure 6 Schematic diagram of the common mode inductor and device provided in this application Figure 3 ;

[0044] Figure 7 Schematic diagram of the common mode inductor and device provided in this application Figure 4 ;

[0045] Figure 8 Schematic diagram of the common mode inductor and device provided in this application Figure 5 ;

[0046] Figure 9 A flowchart illustrating the testing method for the common-mode inductor provided in this application;

[0047] Figure 10 A schematic diagram of the structure of the test device for the common-mode inductor provided in this application;

[0048] Figure 11 This is a schematic diagram of the main control system for the common mode inductor provided in this application;

[0049] Figure 12 Schematic diagram of the structure of the common-mode inductor testing device provided in this application Figure 1 ;

[0050] Figure 13 Schematic diagram of the structure of the common-mode inductor testing device provided in this application Figure 2 ;

[0051] Figure 14 A schematic diagram of the test system provided in this application.

[0052] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0053] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0054] In new energy vehicles, the common-mode inductor is a core component for improving the product's EMC (Electromagnetic Compatibility). The performance of the common-mode inductor directly affects the stability of the equipment in complex electromagnetic environments.

[0055] The core function of a common-mode inductor is to suppress common-mode interference. The suppression of common-mode interference by a common-mode inductor depends on impedance isolation. The larger the common-mode impedance, the stronger the attenuation effect on common-mode noise. Conversely, if the common-mode impedance is insufficient, the attenuation effect on common-mode noise is weaker.

[0056] Common-mode inductance is the core parameter that determines common-mode impedance. Therefore, testing the common-mode inductance is crucial for verifying whether the common-mode inductor can maintain its performance. However, in actual operating conditions, the common-mode inductor is affected by large differential-mode currents, causing its common-mode inductance to decay nonlinearly. This decay characteristic further affects the noise suppression capability of the filter.

[0057] Therefore, it is necessary to accurately test the common-mode inductance of the common-mode inductor under different differential-mode current modes to ensure its consistency in practical applications.

[0058] Existing common-mode inductance testing methods involve measuring the common-mode inductance of a single-phase inductor using an LCR meter (also known as an inductor-capacitor-resistance tester). Figure 1 and Figure 2 As shown, the tester connected the test port of the LCR meter to a single-phase winding of the common-mode inductor and directly measured its inductance value by applying an AC signal.

[0059] However, this test scheme is a single-phase inductance measurement under static conditions, lacking testing under dynamic differential current, and cannot fully evaluate its performance stability in actual operation.

[0060] To address this, this application proposes a testing method for common-mode inductors. By short-circuiting the first terminals of coils with different phase numbers, the distribution patterns of differential-mode current (e.g., 2-phase, 3-phase, 4-phase) are simulated, thus covering various operating scenarios. Subsequently, by controlling the differential-mode current output from a DC source and combining it with inductance measurements from testing instruments, the attenuation rate of the common-mode inductance is calculated. This overcomes the limitations of existing technologies for static single-phase testing, enabling a comprehensive evaluation of the common-mode inductance attenuation characteristics under real differential-mode current conditions.

[0061] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0062] To facilitate understanding of the solution in this application, some of the terms used in this application will be explained first:

[0063] A common-mode inductor is an inductor with two in-phase windings. Its core function is to suppress common-mode interference and allow differential-mode useful current.

[0064] Differential mode current refers to the current flowing in opposite directions, equal in magnitude, and 180° out of phase in a pair of differential conductors (such as the positive and negative terminals of a power line, the positive and negative terminals of a signal line, or the live / neutral wire of the power grid). It is the useful current for the normal operation of a circuit.

[0065] Differential mode inductance refers to the ability of a common mode inductor to impede differential mode current. Numerically, it is equal to the inductance generated by the winding when the differential mode inductor passes through.

[0066] Common mode inductance refers to the ability of a common mode inductor to impede common mode current. Numerically, it is equal to the total inductance of the magnetic fields generated by the two windings when the common mode current passes through.

[0067] Next, the coil connection method for generating the target differential mode current in the common mode inductor, and the connection method between the device and the coil are explained:

[0068] In a common-mode inductor, the first terminals of at least two phase coils that generate the target differential-mode current are short-circuited, a DC source is connected to the second terminals of the at least two phase coils, and a test instrument is connected to both ends of at least one phase coil. Based on this, the distribution pattern of differential-mode current can be simulated, covering a variety of operating scenarios.

[0069] For example, the first end and the second end are opposite sides, such as the first end being the same name end and the second end being the opposite name end; or the first end being the opposite name end and the second end being the same name end.

[0070] For example, a 4-phase common-mode inductor includes four coils: A, B, C, and D.

[0071] When operating in 2-phase mode, there may be three operating differential mode current states: diagonal differential mode current, adjacent differential mode current, and relative differential mode current. The 2-phase operating differential mode current is formed by shorting one side of the same-name terminal of the 2-phase coil corresponding to the operating differential mode current state, and connecting the DC source to the other side of the same-name terminal (opposite-name terminal) of the 2-phase coil.

[0072] like Figure 3 and Figure 4 As shown, the diagonal differential current refers to the current where the same-named terminals of phase A and phase B are shorted, and the DC source is connected to the opposite-named terminals of phase A and phase B; for example... Figure 3 and Figure 5 As shown, the relative position differential current refers to the current where the same-named terminals of phase A and phase C are shorted, and the DC source is connected to the opposite-named terminals of phase A and phase C; for example... Figure 3 and Figure 6 As shown, the differential current between adjacent positions refers to the side where the same-name terminals of phase A and phase N are shorted, and the side where the DC source is connected to the opposite-name terminals of phase A and phase N.

[0073] When operating in 3-phase mode, the 3-phase differential mode current can be generated by shorting the same-name terminals of the 3-phase coils corresponding to the differential mode current state, and connecting the DC source to the opposite-name terminals of the 3-phase coils. For example, shorting the same-name terminals of phase A, phase B, and phase C, and connecting the DC source to the opposite-name terminals of phase A, phase B, and phase C, as shown. Figure 7 As shown; short-circuit the same-name terminals of phase A, phase C, and phase N coils, and connect the DC device to the opposite-name terminals of phase A, phase C, and phase N coils; short-circuit the same-name terminals of phase B, phase C, and phase N coils, and connect the DC source to the opposite-name terminals of phase B, phase C, and phase N coils.

[0074] When operating in 4-phase mode, the 4-phase differential mode current can be generated by shorting one side of the same-name terminals of the 4-phase coils corresponding to the differential mode current state, and connecting the DC source to the opposite-name terminals of the 4-phase coils, such as... Figure 8 As shown.

[0075] Similarly, for other multiphase (three-phase, five-phase, etc.) common-mode inductors, the above short-circuiting method can be used as a reference, and will not be repeated here.

[0076] It should be noted that in practical power electronic circuits such as on-board OBCs and on-board DC-DC converters, differential-mode current is usually a composite current consisting of DC and AC components. The DC component is the main body of the differential-mode current and plays a core role in power transmission; the AC component is additional noise and ripple superimposed on the DC component, and is a non-core parasitic component.

[0077] Therefore, the aforementioned differential mode current can be understood as the DC component of the differential mode current.

[0078] After establishing the differential-mode current, an LCR meter is used to test the common-mode inductance under this current. The AC measurement signal from the LCR meter and the bias current from the DC source need to be superimposed and injected into the common-mode inductor under test. Specifically, the positive terminal (L+) of the LCR meter and the positive terminal (DC+) of the DC source are connected to the same-name terminal of phase A coil; the negative terminal (LCR-) of the LCR meter is connected to the opposite-name terminal of phase A coil. Simultaneously, the negative terminal (DC-) of the DC source is connected to the same-name terminal of phase B coil. With this connection, the LCR meter outputs a high-frequency AC test signal and measures the inductance, while the DC source injects DC current to simulate the actual differential-mode operating bias. Only through their combined action can the common-mode inductance under a specified DC bias be measured.

[0079] Next, the test method for the common-mode inductor provided in this application will be described:

[0080] Figure 9 A flowchart illustrating the testing method for the common-mode inductor provided in this application is shown below. Figure 9 As shown, the first ends of at least two phase coils that form the target differential mode current in the common-mode inductor are short-circuited, a DC source is connected to the second ends of the at least two phase coils, and a test instrument is connected to both ends of at least one phase coil. The common-mode inductor test method provided in this application embodiment includes:

[0081] S101. Obtain the reference inductance measured by the test instrument when the DC source output current is zero.

[0082] For example, the target differential mode current may include two-phase differential mode current, three-phase differential mode current, etc., and the specific current can be determined according to the actual situation of the common mode inductor.

[0083] A DC source is a power supply that injects a DC bias current into the common-mode inductor under test. It is used to simulate the DC or low-frequency differential-mode operating current flowing through the winding of the common-mode inductor in a real circuit (such as the input stage of a switching power supply). This current will establish a DC magnetic field bias in the magnetic core.

[0084] The output current of a DC source is zero, meaning there is no DC current output at its output terminals, representing a reference or initial state. In this state, the core of the common-mode inductor is not affected by any DC magnetization force and is in an unbiased, pristine magnetic state.

[0085] Test instruments refer to instruments used to measure inductance, such as LCR meters (inductance, capacitance, and resistance meters). An LCR meter injects a high-frequency, low-amplitude AC test signal into the inductor under test and accurately measures its voltage, current, and phase relationship, thereby calculating parameters such as impedance and inductance at that frequency.

[0086] The reference inductance is the value of a common-mode inductor measured by a test instrument under specific conditions where the DC bias current is zero. The reference inductance represents the inherent characteristics of a common-mode inductor when there is no operating current, and serves as a reference point for evaluating performance variations. All subsequent operating inductance measurements under different DC bias currents will be compared to the reference inductance.

[0087] For example, with the first ends of at least two phase coils forming the target differential mode current in the common-mode inductor short-circuited, a DC source connected to the second ends of the at least two phase coils, and a test instrument connected to both ends of at least one phase coil, the DC source is controlled to output zero current; when the DC source outputs zero current, the test instrument is controlled to measure the corresponding reference inductance. Accordingly, the reference inductance measured by the test instrument when the DC source output current is zero can be obtained.

[0088] S102. Under the condition that the reference inductance meets the preset requirements, obtain the working inductance measured by the test instrument when the DC source output current is the working differential mode current.

[0089] For example, the preset requirements refer to the explicit specifications in the product specifications or testing standards regarding the inductance range and tolerances that the common-mode inductor should possess under unbiased conditions. Only after confirming that the inductor's basic performance (i.e., zero-bias inductance, or reference inductance) is qualified is it necessary to continue testing its performance under bias. If the reference inductance itself does not meet the standard, the common-mode inductor is already unqualified.

[0090] Operating differential mode current refers to the steady-state DC current or low-frequency differential mode current that is expected to flow through the winding of a common mode inductor in its target application circuit (such as the input filter network of a certain type of switching power supply). It is a key test condition for simulating real operating conditions. The output current of the DC source is precisely set to this specified value and injected into the winding of the common mode inductor.

[0091] Operating inductance refers to the inductance of a common-mode inductor measured by a test instrument under the condition of applying a specified differential-mode current as a DC bias. The inductance measured at this time is essentially the inductance corresponding to the incremental permeability of the magnetic core at a specific DC bias point, reflecting the inductor's actual ability to suppress high-frequency noise (common-mode interference) under operating conditions.

[0092] For example, when the reference inductance meets preset requirements, the DC source can be controlled to output the operating differential mode current; when the DC source outputs the operating differential mode current, the testing instrument can be controlled to measure the corresponding operating inductance. Accordingly, the operating inductance measured by the testing instrument when the DC source output current is the operating differential mode current can be obtained.

[0093] Optionally, in response to a test command input by the user, the current test condition is determined; based on the test condition, the range of output current variation of the DC source is determined; and based on the range of output current variation of the DC source, the operating differential current is determined.

[0094] A test command is a command or request issued by a user (operator, engineer, or host computer software) to initiate a specific test. It can be a button click on a software interface, a command-line instruction, or a configuration file containing test parameters. This test command is not only a trigger signal to start the test, but also implicitly or explicitly includes the goal and conditions of this test, such as testing type A electrical components, performing a high-temperature full-load test, or conducting an acceptance test according to preset standards.

[0095] The current test condition is a set of parameters parsed or mapped from the test command, defining the specific environment and conditions of this test. It may include information about the device under test (DUT), test standards / specifications, environmental conditions, and test type. DUT information includes inductor model, rated current, and application scenario; test standards / specifications include which industry standard, internal control standard, or customer-specific requirement is followed; environmental conditions include whether testing is required at specific temperatures and humidity levels; and test types include R&D verification, full production inspection, and incoming material sampling inspection. The test condition acts as an intermediary layer connecting user intent with specific equipment parameters, transforming abstract commands into engineering-definable test conditions.

[0096] The output current range of a DC source refers to the range of current that the source needs to output and scan from its minimum to its maximum value to complete the test. For example, if the test condition is a rated current test, the range could be [0A, rated current]; if the test condition is a saturation current curve test, the range could be [0A, 120% of the expected saturation current]; if the test condition is a stress test verifying three times the rated current, the range could be [0A, 3 times the rated current]. The output current range defines the stress intensity boundary of the test, ensuring that the DC source is set within the correct and safe range, preparing for the next step of selecting specific test points.

[0097] S103. Based on the reference inductance and the operating inductance, determine the inductance decay rate of the common-mode inductor under the operating differential-mode current. The inductance decay rate is used to characterize the performance of the common-mode inductor.

[0098] Inductance decay rate refers to the degree to which the inductance value of a common-mode inductor decreases relative to the reference inductance at zero bias after a working differential-mode current (DC bias) is applied. It is usually expressed as a percentage.

[0099] The formula for calculating the inductance decay rate is: [(Reference Inductance - Operating Inductance) / Reference Inductance] × 100%. The inductance decay rate quantifies the impact of DC bias on the inductor core performance. A smaller decay rate indicates lower core saturation when the common-mode inductor is subjected to operating current, resulting in more stable noise suppression capability (inductance). Accordingly, the performance of a common-mode inductor can be characterized based on the inductance decay rate.

[0100] For example, when the DC source output current is zero, the test instrument can measure the inductance at multiple test frequencies; when the DC source output current is the operating differential mode current, the test instrument can also measure the inductance at multiple test frequencies. Accordingly, both the reference inductance and the operating inductance can include inductance at multiple test frequencies.

[0101] Optionally, both the reference inductance and the operating inductance can include inductance at multiple test frequencies. The inductance attenuation rate at each test frequency can then be determined based on the reference inductance and the operating inductance at each test frequency. Here, the test frequency refers to the frequency of the sinusoidal AC signal generated by the test instrument and applied to the inductor under test to measure its inductance parameters.

[0102] Since the inductance of a common-mode inductor varies with frequency—for example, as the frequency increases, the inductance naturally decreases due to factors such as core losses and parasitic capacitance—and further attenuates across the entire frequency band after applying a DC bias, multiple test frequencies covering the target operating frequency band of the inductor are selected to comprehensively and reliably evaluate the inductance attenuation rate, thereby accurately determining the performance of the common-mode inductor.

[0103] Optionally, when the inductance attenuation rate is less than a preset attenuation rate threshold, the performance of the common-mode inductor is determined to be in a stable state, meeting the consistency requirements; when the inductance attenuation rate is greater than or equal to the preset attenuation rate threshold, the performance of the common-mode inductor is determined to be in an unstable state, failing to meet the consistency requirements. This transforms the consistency of the common-mode inductor from an abstract concept into a manufacturing attribute that can be rapidly and accurately verified on the production line. It not only ensures the performance stability of individual inductors but also guarantees a high degree of consistency in the performance of thousands of products through rigorous process control.

[0104] Accordingly, after determining the inductance attenuation rate at multiple test frequencies, it is possible to determine whether the performance of the common-mode inductor is in a stable state based on the inductance attenuation rate at multiple test frequencies. For example, if the inductance attenuation rate at most (e.g., more than 80%) or all test frequencies is less than a preset attenuation rate threshold, it is determined that the performance of the common-mode inductor is in a stable state.

[0105] In other examples, after determining the inductance decay rate of multiple common-mode inductors, the inductance decay rates of the multiple common-mode inductors can be compared. If they are consistent or nearly consistent, the common-mode inductors are determined to meet the consistency requirements.

[0106] To facilitate understanding of the solution in this application, the following detailed steps will be provided for analysis and explanation:

[0107] The current test condition is determined based on the test command input by the user, and the range of output current variation of the DC source is controlled according to the test condition.

[0108] When the DC source output current is 0A, the LCR meter detects the inductance L1, L2, ..., Ln of the common mode inductor at different test frequencies;

[0109] Determine whether the inductance values ​​L1, L2, ..., Ln meet the corresponding preset threshold requirements;

[0110] If satisfied, then when the output current of the DC device is the working differential mode current (determined according to the variation range of the DC source confirmed above), the inductance L1', L2', ..., Ln' of the common mode inductor detected by the LCR meter at different test frequencies;

[0111] Calculate the common-mode inductance attenuation rate of the common-mode inductor under the working differential-mode current at each corresponding test frequency based on the inductances L1, L2, ..., Ln and L1', L2', ..., Ln'.

[0112] Attenuation rate = (1 - L1' / L2) × 100%;

[0113] Determine whether the common-mode inductance attenuation rate under the working differential-mode current is less than the preset attenuation rate threshold at each test frequency.

[0114] If the preset attenuation rate threshold is met, then the consistency requirement is met.

[0115] The common-mode inductor testing method provided in this application simulates the differential-mode current distribution pattern by short-circuiting the first terminal of coils with different phase numbers, thereby covering various operating scenarios. Subsequently, by controlling the differential-mode current output of the DC source and combining it with the inductance measurement of the testing instrument, the attenuation rate of the common-mode inductance is calculated. This overcomes the limitations of existing technologies for static single-phase testing and enables a comprehensive evaluation of the common-mode inductance attenuation characteristics under real differential-mode current conditions.

[0116] Figure 10 A schematic diagram of the structure of the common-mode inductor testing device provided in this application is shown below. Figure 10As shown, the first ends of at least two phase coils that form the target differential mode current in the common-mode inductor are short-circuited, a DC source is connected to the second ends of at least two phase coils, and a test instrument is connected to both ends of at least one phase coil. The common-mode inductor test apparatus 10 provided in this embodiment includes:

[0117] The first processing module 11 is used to obtain the reference inductance measured by the test instrument when the DC source output current is zero.

[0118] The second processing module 12 is used to obtain the working inductance measured by the test instrument when the DC source output current is the working differential mode current, provided that the reference inductance meets the preset requirements.

[0119] The third processing module 13 is used to determine the inductance decay rate of the common-mode inductor under the operating differential-mode current based on the reference inductance and the operating inductance. The inductance decay rate is used to characterize the performance of the common-mode inductor.

[0120] In one possible implementation, the reference sensitivity and the operating sensitivity include the sensitivity at multiple test frequencies; the third processing module 13 is specifically used to determine the sensitivity attenuation rate at each test frequency based on the reference sensitivity and the operating sensitivity at each test frequency.

[0121] In one possible implementation, the third processing module 13 is further configured to determine that the performance of the common-mode inductor is in a stable state when the inductance attenuation rate is less than a preset attenuation rate threshold; and to determine that the performance of the common-mode inductor is in an unstable state when the inductance attenuation rate is greater than or equal to the preset attenuation rate threshold.

[0122] In one possible implementation, the third processing module 13 is further configured to, in response to a test command input by the user, determine the current test condition; determine the range of output current variation of the DC source based on the test condition; and determine the operating differential current based on the range of current variation.

[0123] The common-mode inductor testing device provided in this embodiment can execute the method provided in the above-described method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0124] Figure 11 A schematic diagram of the main control system provided in this application. Figure 11 As shown, the main control system 204 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the main control system 204 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus.

[0125] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0126] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0127] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0128] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0129] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0130] Figure 12 A schematic diagram of the structure of the common-mode inductor testing device provided in this application is shown below. Figure 12 As shown, the common-mode inductor testing apparatus 20 provided in this embodiment includes...

[0131] The aforementioned main control system 204, DC power supply 201, and testing instrument 202;

[0132] The main control system 204 is connected to the DC power source 201 and the test instrument 202;

[0133] DC source 201 is connected to the second ends of at least two phase coils of common mode inductor, test instrument 202 is connected to the two ends of at least one phase coil of common mode inductor, and the first ends of at least two phase coils of common mode inductor that form the target differential mode current are short-circuited.

[0134] The common-mode inductor testing device in this application embodiment can efficiently perform full offline inspection of common-mode inductors, quickly and accurately assess whether the common-mode inductance value under the working differential-mode current meets the requirements, thereby improving the consistency of the common-mode inductor under the working differential-mode current.

[0135] For example, the positive terminal of DC source 201 is connected to the same-name terminal of the first coil of the common-mode inductor, and the negative terminal of DC source 201 is connected to the same-name terminal of at least one other coil (a coil other than the first coil) of the common-mode inductor, for outputting a DC signal; the positive and negative terminals of test instrument 202 are respectively connected to the same-name terminal and the opposite-name terminal of the first coil, for providing an AC excitation signal; the sampling terminal of test instrument 202 is also connected to the same-name terminal and the opposite-name terminal of the first coil, for measuring the common-mode inductance of the common-mode inductor when the opposite-name terminal of the coil corresponding to the differential-mode operating current is short-circuited. By short-circuiting one side of the opposite-name terminal of the coil corresponding to the operating differential-mode current state, and connecting the DC source to the same-name terminal of the coil, an operating differential-mode current can be formed when DC source 201 provides a DC signal and test instrument 202 provides an AC signal, and then the common-mode inductance under the differential-mode current can be measured by test instrument 202.

[0136] In a multi-coil inductor (such as a common-mode inductor with multiple windings), the magnetic flux generated by each coil is superimposed and enhanced in the core when current flows into the same-coil terminals. Conversely, once the same-coil terminals of a coil are determined, the other end of that coil becomes the opposite-coil terminal. If current flows into the same-coil terminal of one coil and into the opposite-coil terminal of another coil, the magnetic flux generated by the two coils will cancel each other out.

[0137] For example, taking a four-phase differential mode inductor as an example, the four coils of the four-phase differential mode inductor are respectively called the first coil (also called the first phase inductor), the second coil (also called the second phase inductor), the third coil (also called the third phase inductor) and the fourth coil (also called the fourth phase inductor).

[0138] When the four-phase differential-mode inductor operates with two-phase differential-mode current, the positive terminal of DC source 201 is connected to the same-name terminal of the first coil, and the negative terminal of DC source 201 is connected to the same-name terminal of the second coil. The positive terminal of test instrument 202 is connected to the same-name terminal of the first coil, and the negative terminal of test instrument 202 is connected to the opposite-name terminal of the first coil. The sampling terminals of test instrument 202 include a first sampling terminal and a second sampling terminal. The first sampling terminal is connected to the same-name terminal of the first coil, and the second sampling terminal is connected to the opposite-name terminal of the first coil. Test instrument 202 can also measure the common-mode inductance of the common-mode inductor when operating with two-phase differential-mode current, with the opposite-name terminals of the first and second coils short-circuited.

[0139] When the four-phase differential-mode inductor operates with three-phase differential-mode current, the positive terminal of DC source 201 is connected to the same-name terminal of the first coil, and the negative terminal of DC source 201 is connected to the same-name terminals of the second and third coils. The positive terminal of test instrument 202 is connected to the same-name terminal of the first coil, and the negative terminal of test instrument 202 is connected to the opposite-name terminal of the first coil. The first sampling terminal of test instrument 202 is connected to the same-name terminal of the first coil, and the second sampling terminal is connected to the opposite-name terminal of the first coil. Test instrument 202 can also measure the common-mode inductance of the common-mode inductor operating with three-phase differential-mode current when the opposite-name terminals of the first, second, and third coils are short-circuited.

[0140] When the four-phase differential-mode inductor operates with four-phase differential-mode current, the positive terminal of DC source 201 is connected to the same-name terminal of the first coil, and the negative terminal of DC source 201 is connected to the same-name terminals of the second, third, and fourth coils. The positive terminal of test instrument 202 is connected to the same-name terminal of the first coil, and the negative terminal of test instrument 202 is connected to the opposite-name terminal of the first coil. The first sampling terminal of test instrument 202 is connected to the same-name terminal of the first coil, and the second sampling terminal is connected to the opposite-name terminal of the first coil. Test instrument 202 can also measure the common-mode inductance of the common-mode inductor operating with four-phase differential-mode current when the opposite-name terminals of the first, second, third, and fourth coils are short-circuited.

[0141] It should be noted that differential mode inductors can be two-phase, three-phase, four-phase, or multi-phase.

[0142] Optional, such as Figure 13 As shown, the testing device 20 for testing common-mode inductors also includes an AC source 206 and an AC / DC isolation circuit 203. The AC source 206 is connected to the main control system 204, the DC source 201, and the AC source 206, and is used to provide AC power to the main control system 204, the DC source 201, and the AC source 206. The DC source 201 can convert the AC power provided by the AC source 206 into DC power and supply it to the common-mode inductor. The AC / DC isolation circuit 203 is set between the testing instrument 202 and the DC source 201 to isolate AC and DC signals. The overlap of AC and DC signals will cause the common-mode inductance obtained by the testing instrument 202 under the differential-mode current to not meet the accuracy requirements. Therefore, when testing the common-mode inductance under the differential-mode current, the AC / DC isolation circuit 203 is set between the testing instrument and the DC source to improve the testing accuracy.

[0143] For example, the AC / DC isolation circuit 203 includes an isolation circuit consisting of an inductor and a capacitor.

[0144] Optionally, the DC source 201 includes at least two DC source slaves. Multiple DC source slaves can be used in parallel, and their output currents can be superimposed to easily obtain a large current that cannot be provided by a single device, in order to simulate the real working conditions of certain high-power common-mode inductors (such as those used for three-phase motor drives and high-power server power supplies).

[0145] For example, the DC source may also include a DC source slave.

[0146] Optionally, the test instrument 202 may include an LCR meter, which can accurately measure the parameters of passive components such as inductors, capacitors, and resistors. By applying an AC test signal of known frequency and amplitude and accurately measuring the vector voltage and current across the device under test, the impedance and its components can be directly calculated.

[0147] For example, test instrument 202 may also include an impedance analyzer, as well as other devices capable of measuring impedance.

[0148] For example, such as Figure 12 As shown, the common-mode inductor testing device 20 also includes a display device 205, which is connected to the main control system 203 and used to display test parameters and / or test results. The display device 205 provides users with an intuitive and user-friendly interface for parameter setting and result observation, thus constructing a high-performance common-mode inductor testing system integrating automatic control, precise measurement, data analysis, and result presentation.

[0149] This application also provides a testing system, such as Figure 14 As shown, the test apparatus 20 and test fixture 10 for the common mode inductor described above are included.

[0150] The test fixture 10 is used to hold the common-mode inductor and short-circuit the first ends of at least two phase coils of the common-mode inductor that form the target differential-mode current, according to the test conditions.

[0151] For example, the testing system may also include barcode scanners, workbenches, etc., to improve testing efficiency and ease of operation.

[0152] The testing system provided in this application not only develops dedicated test fixtures to improve testing efficiency, but also efficiently performs full inspection of common-mode inductors after production, quickly and accurately assesses whether the common-mode inductance value under operating differential-mode current meets the requirements, thereby improving the consistency of common-mode inductors under operating differential-mode current.

[0153] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0154] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0155] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0156] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0157] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0158] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0159] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0160] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0161] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0162] Finally, it should be noted that other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and alterations may be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method of testing a common mode inductance, characterized by, The first end of at least two phase coils in the common mode inductor forming a target differential mode current is short-circuited, a DC source is connected to the second end of the at least two phase coils, and a test instrument is connected to the two ends of at least one phase coil, and the method comprises: obtaining a reference inductance measured by the test instrument when the DC source output current is zero current; in the case that the reference inductance meets the preset requirement, obtaining a working inductance measured by the test instrument when the DC source output current is a working differential mode current; determining an inductance attenuation rate of the common mode inductor under the working differential mode current according to the reference inductance and the working inductance, and the inductance attenuation rate is used to represent the performance of the common mode inductor.

2. The method of claim 1, wherein, The reference inductance and the working inductance comprise inductances under multiple test frequencies. The method further comprises: in the case that the inductance attenuation rate is less than a preset attenuation rate threshold, determining that the performance of the common mode inductor is in a stable state; 3. The method of claim 1, wherein, in the case that the inductance attenuation rate is greater than or equal to the preset attenuation rate threshold, determining that the performance of the common mode inductor is in a non-stable state. The method further comprises: in response to a test instruction input by a user, determining a current test working condition; 4. The method according to any one of claims 1 to 3, characterized in that, determining an output current variation range of the DC source according to the test working condition; determining the working differential mode current according to the current variation range. comprise: a memory and a processor; 5. A master system characterized by comprising: the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory, so that the processor executes the method according to any one of claims 1-4. comprise the master control system, the DC source and the test instrument according to claim 5; the master control system is connected to the DC source and the test instrument; 6. A test device for common mode inductance, characterized by the DC source is connected to the second end of at least two phase coils of the common mode inductor, the test instrument is connected to the two ends of at least one phase coil of the common mode inductor, and the first end of at least two phase coils forming a target differential mode current in the common mode inductor is short-circuited. The test device of the common mode inductor further comprises: an AC source, which is respectively connected to the master control system, the test instrument and the DC source; 7. The test device for common mode inductance according to claim 6, characterized in that an AC-DC isolation circuit, which is arranged between the test instrument and the DC source and is used to isolate AC signals and DC signals. The DC source comprises at least two DC source slaves; and / or, the test instrument comprises an LCR meter.

8. The test device for common mode inductance according to claim 7, characterized in that, The test device of the common mode inductor according to any one of claims 6-8 and a test fixture are comprised; the test fixture is used to clamp the common mode inductor and short-circuit the first end of at least two phase coils forming a target differential mode current in the common mode inductor according to a test working condition.

9. A test system for common mode inductance, characterized by The computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by the processor to implement the method according to any one of claims 1-4. ​ 10. A computer-readable storage medium, characterized in that, ​

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