Power converter common mode conducted interference black box modeling method and system based on impedance parameter online identification

Abstract

The invention belongs to the field of power electronic electromagnetic compatibility, and discloses a power converter common-mode conducted interference black box modeling method and system based on impedance parameter on-line identification, which realize on-line identification of common-mode impedance parameters by extracting broadband scattering parameters (S parameters) of a power converter common-mode conducted interference path. And in combination with the impedance parameters and current data measured on line, a common-mode conducted emission black box model of the power converter is constructed. According to the invention, the impedance parameter and the current data can be obtained online, and the characterization precision of the black box model on the common-mode conducted interference characteristic of the power converter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic electromagnetic compatibility, and in particular to a black box modeling method and system for common-mode conducted interference of a power converter based on online identification of impedance parameters. Background Art

[0002] With the continuous development of SPWM control technology and the widespread application of new semiconductor materials such as SiC and GaN, power converters have achieved higher switching frequencies, greater power density and lower power losses. However, this also leads to higher voltage changes (dv / dt) and current changes (di / dt). During operation, the conducted interference noise generated by power conversion devices causes electromagnetic interference to sensitive equipment and becomes the main source of electromagnetic interference. By modeling the power converter, not only can the conducted interference emission intensity be predicted, but also the factors affecting the conducted emission can be analyzed, thereby providing effective guidance for electromagnetic compatibility design and protection.

[0003] Existing modeling methods are mainly divided into two categories: physical models and behavioral models. The physical model establishes a high-frequency equivalent circuit model by comprehensively considering factors such as the working mechanism of the device and parasitic parameters under high-frequency conditions, thereby realizing the prediction and analysis of the conducted interference characteristics of the power switching device. However, in large multi-electric systems such as aircraft and ships, parasitic parameters are difficult to extract accurately, making it a huge challenge to establish an accurate circuit model. The behavioral model (black box model) establishes an equivalent model through external measurement data of the power converter. This method is relatively simple and versatile, and is especially suitable for the conducted interference analysis of complex systems.

[0004] In the process of parameter identification, most of the existing black box modeling methods use the device offline or by changing the external load to identify the equivalent impedance parameters. However, the power switching device itself is a nonlinear device, and its equivalent impedance changes with the working conditions. Therefore, the traditional parameter identification method will cause the impedance parameters of the established model to be mismatched with the equivalent interference source, and cannot well reflect the conducted emission characteristics of the power converter. Therefore, it is of engineering significance to realize the black box modeling of the impedance parameters of the power converter online. Summary of the invention

[0005] In order to solve the problem that the impedance parameters of the current conducted emission black box modeling cannot be identified online, resulting in large model errors, the present invention provides a black box modeling method and system for common-mode conducted interference of power converters based on online identification of impedance parameters, which can realize online acquisition of impedance parameters and current data, and improve the characterization accuracy of the black box model for the common-mode conducted interference characteristics of the power converter.

[0006] The present invention discloses a black box modeling method for common mode conducted interference of a power converter based on online identification of impedance parameters, the method comprising:

[0007] By extracting the broadband scattering parameters of the common-mode conduction interference path of the power converter, the common-mode impedance parameters can be identified online.

[0008] Combining the online identified common-mode impedance parameters with the online measured current data, a common-mode conducted emission black box model of the power converter is constructed.

[0009] Preferably, performing online identification of common-mode impedance parameters by extracting broadband scattering parameters of the common-mode conduction interference path of the power converter includes:

[0010] Based on the impedance value Z of the three calibration components and the wire i , i=1,2,3 and the corresponding S11 parameter S i， i=1,2,3, construct three equations, solve the equations, and calculate the three calibration coefficients k required for online identification of impedance parameters. i， i=1,2,3;

[0011] S11 parameter S based on online measurement cm1 With three calibration coefficients k i， i=1,2,3, calculate the online impedance Z of the entire loop loop ;

[0012] Based on the measured S11 parameter S cm2 and three calibration coefficients k i， i=1,2,3, calculate the external impedance Z of the power converter out ;

[0013] Based on the online impedance Z of the entire loop loop and the power converter external impedance Z out , calculate the common-mode equivalent impedance Z of the power converter under typical operating conditions con_CM .

[0014] Preferably, based on the impedance value Z of the three calibration elements and the wire i , i=1,2,3 and the corresponding S11 parameter S i , i=1,2,3, construct three equations, solve the equations, and calculate the three calibration coefficients k required for online identification of impedance parameters i , i=1,2,3 include:

[0015]

[0016] Preferably, based on the online measured S11 parameter S cm1 With three calibration coefficients k i , i=1,2,3, calculate the online impedance Z of the entire loop loop include:

[0017]

[0018] Preferably, based on the measured S11 parameter S cm2 and three calibration coefficients k i , i=1,2,3, calculate the external impedance Z of the power converter out include:

[0019]

[0020] Preferably, based on the online impedance Z of the entire loop loop and the power converter external impedance Z out , calculate the common-mode equivalent impedance Z of the power converter under typical operating conditions con_CM include:

[0021] Z con_CM =Z loop -Z out .

[0022] Preferably, combining the common-mode impedance parameters identified online with the current data measured online to construct a common-mode conducted emission black box model of the power converter includes:

[0023] Measuring the common-mode conducted interference current I of the power supply cable harness of the power converter CM ;

[0024] Based on the common mode conducted interference current I CM The online impedance Z of the entire loop loop , calculate the power converter common mode equivalent interference source E th_CM ;

[0025] Based on the obtained power converter common mode equivalent interference source E th_CM The common-mode equivalent impedance Z of the power converter under typical working conditions con_CM , build its common-mode conducted interference black box model.

[0026] Preferably, based on the common mode conducted interference current I CM The online impedance Z of the entire loop loop , calculate the power converter common mode equivalent interference source E th_CM include:

[0027] E th_CM =Z loop I CM .

[0028] The present invention also provides a black box modeling system for common-mode conducted interference of a power converter based on online identification of impedance parameters, wherein the system is used in any one of the methods described, and comprises: an identification module and a construction module;

[0029] The identification module is used to perform online identification of common mode impedance parameters by extracting broadband scattering parameters of the common mode conduction interference path of the power converter;

[0030] The construction module is used to combine the common-mode impedance parameters identified online with the current data measured online to construct a common-mode conducted emission black box model of the power converter.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention realizes online identification of common-mode impedance parameters by extracting broadband scattering parameters (S parameters) of the common-mode conduction interference path of the power converter, and constructs a common-mode conduction emission black box model of the power converter by combining the impedance parameters with the current data measured online. The present invention can realize online acquisition of impedance parameters and current data, and improve the characterization accuracy of the black box model for the common-mode conduction interference characteristics of the power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 This is a schematic diagram of the S parameter measurement principle of the calibration process of an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the online measurement principle of loop impedance according to an embodiment of the present invention;

[0036] Figure 3 1 is a loop impedance measurement equivalent circuit diagram of an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the external impedance measurement principle of an embodiment of the present invention;

[0038] Figure 5 An equivalent circuit diagram of external impedance measurement according to an embodiment of the present invention;

[0039] Figure 6 This is a common mode current measurement principle diagram of an embodiment of the present invention;

[0040] Figure 7 It is a schematic diagram of an equivalent common-mode conducted interference model of a power converter according to an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of comparison results (amplitude) of measuring RLC elements using an impedance parameter online identification method according to an embodiment of the present invention;

[0042] Fig. 9 A schematic diagram of comparison results (phase) of measuring RLC elements using an impedance parameter online identification method according to an embodiment of the present invention;

[0043] Fig.10 It is a schematic diagram for comparing the effects of the black box modeling method based on online identification of impedance parameters according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0046] First, some technical terms used in the present invention are explained:

[0047] Impedance analyzer: The core function of the impedance analyzer is to measure the change of complex electrical impedance (including amplitude and phase) with the test frequency. Impedance is an important parameter to characterize electronic components, electronic circuits and component materials. By measuring impedance, the electrical characteristics of these devices and materials can be understood. The impedance analyzer has two ports, and the impedance parameters are measured by clamping the measured component between the two ports. The present invention uses the impedance analyzer to measure the impedance parameters of the calibration component and obtain the calibration coefficient for online identification of the impedance parameters.

[0048] Vector network analyzer: mainly used to measure S parameters online, using a current injection probe to connect port1 to measure its S parameters. The S parameter is expressed as the ratio of the output power of the port to the input power, in decibels (dB). The vector network analyzer has two ports, Port1 and Port2. The present invention is connected to Port1 to measure its S11 parameter. S11 characterizes the reflection coefficient of Port1 at different frequencies, and is used to characterize the degree of reflection of the signal input from Port1 at different frequencies at the same port. Using S11 and three calibration coefficients, online measurement of impedance parameters can be achieved.

[0049] Spectrum analyzer: Mainly used to detect the spectrum of current signals. Pass the positive and negative poles of the power line of the power converter through the inner side of the current detection probe, and connect the current detection probe to the RF input port of the spectrum analyzer to measure the common-mode current of the power converter. The equivalent interference source of the power converter can be calculated by using the common-mode current and the impedance parameters measured online.

[0050] A broadband current injection probe is an electronic test device that is mainly used to measure current signals in AC circuits. Its working principle is based on electromagnetic induction and the Hall effect. It induces a voltage signal proportional to the measured current and then amplifies the signal through a signal amplifier for measurement. This probe is very important in the electronics industry because it can help engineers test circuits and troubleshoot problems quickly and accurately. LISN (Line Impedance Stabilization Network) is an important auxiliary device in electromagnetic compatibility testing, used to isolate power supply interference and provide stable test impedance. In EMC testing, LISN is connected between the power supply and the device. Its main functions include: 1 Isolate power supply interference: LISN is designed with filtering components and 50Q impedance to ensure test consistency and allow the power supply to supply normally. 2 Provide stable test impedance: LISN provides a constant impedance for the noise loop, which is 25Ω for common mode. 3 Convert noise current to noise voltage for measurement: LISN isolates high-frequency noise and electromagnetic interference introduced on the power line, simulates the electromagnetic environment faced by the device in actual use, and provides more realistic and reliable results for subsequent electromagnetic compatibility testing.

[0051] A current probe is a device used to measure current by converting the current signal into a voltage signal that the instrument can read and understand. A current probe usually consists of a clip-like sensor and a connection interface that can clamp the current conductor and connect the sensor to the measuring instrument or meter through the connection interface.

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] Embodiment 1

[0054] An embodiment of the present invention provides a black box modeling method for common-mode conducted interference of a power converter based on online identification of impedance parameters, the method comprising:

[0055] By extracting the broadband scattering parameters of the common-mode conduction interference path of the power converter, the common-mode impedance parameters can be identified online.

[0056] Combining the online identified common-mode impedance parameters with the online measured current data, a common-mode conducted emission black box model of the power converter is constructed.

[0057] (1) Online identification of impedance parameters

[0058] 1. Connect the three calibration resistor elements through wires to form a closed loop and pass them through the inner side of the broadband current injection probe. Connect the broadband current injection probe to Port1 of the vector network analyzer and measure the S11 parameter. The measurement principle is as follows: Figure 1 As shown in the figure, the S11 parameter represents the reflection coefficient of Port1. At the same time, the impedance values ​​of the three calibration components and the wires are measured using an impedance analyzer. Based on the impedance values ​​Z of the three calibration components and the wires i (i=1,2,3) and its corresponding S11 parameter S i (i=1,2,3), construct three equations, and by solving the equations, the three calibration coefficients k required for online identification of impedance parameters can be calculated. i (i=1,2,3).

[0059]

[0060] 2. The power supply is connected to the power conversion device through a linear impedance stabilization network (LISN), and the power conversion device is operated under typical conditions. A broadband current injection probe is used to insert into the common mode loop. The broadband current injection probe is connected to the Port1 port of the vector network analyzer to measure the S11 parameter S of the common mode loop online. cm1 , the measurement settings are as follows Figure 2 The corresponding equivalent circuit is shown as Figure 3 As shown. S11 parameter S based on online measurement cm1 With three calibration coefficients k i (i=1,2,3), calculate the online impedance Z of the entire loop loop .

[0061]

[0062] 3. The external impedance of the power converter can be regarded as a linear passive component and can be accurately measured offline. Short-circuit the power converter offline and measure the S11 parameter S of the external common mode loop. cm2 , the measurement principle is as follows Figure 4 The corresponding equivalent circuit is shown as Figure 5 Based on the measured S11 parameter S cm2 and three calibration coefficients k i (i=1,2,3), calculate the external impedance Z of the power converter out .

[0063]

[0064] 4. By subtracting the entire loop impedance from the external impedance, the common-mode equivalent impedance Z of the power converter under typical operating conditions can be calculated. con_CM .

[0065] Z con_CM =Z loop -Z out

[0066] (2) Calculation of equivalent interference sources

[0067] 1. Make the equipment operate under typical working conditions, and clamp the two power lines of the power converter inside the current detection probe. Connect the current detection probe to the spectrum analyzer to measure the common-mode conducted interference current I of the power converter power supply cable harness. CM , the measurement configuration is as follows Figure 6 Based on the current and impedance data measured online, the equivalent interference source E can be calculated. th_CM .

[0068] E th_CM =Z loop I CM

[0069] 2. Based on the obtained power converter common mode equivalent interference source E th_CM And the equivalent impedance Z con_CM , the common-mode conduction interference black box model can be constructed as follows Figure 7 As shown in Figure 2, the model can characterize the common-mode conducted interference characteristics of the power converter. out When the impedance changes, the established black box model can be used to predict and calculate the common-mode conducted interference current I under the external impedance condition. CM_CAL .

[0070] I CM_CAL =E th_CM / (Z con_CM +Z out )

[0071] The technical solution of the present invention uses resistors, inductors, and capacitors to experimentally verify the effectiveness of the impedance parameter identification method. Figure 8 , Fig. 9 By comparing the impedance parameter online identification method proposed in the present invention with the impedance amplitude and phase measured by the impedance analyzer, it can be seen that the method has high accuracy and can achieve effective identification of impedance parameters.

[0072] pass Fig.10 By comparing the predicted values ​​of the common-mode black box model based on online identification of impedance parameters with the actual measured values ​​of the common-mode current under different working conditions, it can be seen that the modeling method proposed in the present invention can better predict the envelope of the common-mode conducted interference current and effectively predict the maximum common-mode conducted interference current of the power converter, thereby characterizing its common-mode conducted emission characteristics.

[0073] It should be noted that the method of the embodiment of the present disclosure can be performed by a single device, such as a computer or a server. The method of the present embodiment can also be applied in a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present disclosure, and the multiple devices will interact with each other to complete the described method.

[0074] It should be noted that some embodiments of the present disclosure are described above. Other embodiments are within the scope of the attached claims. In some cases, it should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention. The actions or steps recorded in the claims can be performed in an order different from that in the above embodiment and still achieve the desired results. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0075] Embodiment 2

[0076] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present invention further provides a black box modeling system for common-mode conducted interference of a power converter based on online identification of impedance parameters, wherein the system is used in any of the above-mentioned methods, and comprises: an identification module and a construction module;

[0077] The identification module is used to perform online identification of common mode impedance parameters by extracting broadband scattering parameters of the common mode conduction interference path of the power converter;

[0078] The construction module is used to combine the common-mode impedance parameters identified online with the current data measured online to construct a common-mode conducted emission black box model of the power converter.

[0079] The system of the above embodiment is used to implement a corresponding black box modeling method of common-mode conducted interference of a power converter based on online identification of impedance parameters in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0080] It should be noted that the above-mentioned power converter common mode conducted interference black box modeling system based on online impedance parameter identification is embodied in the form of functional units. The term "module" here can be implemented in the form of software and / or hardware, and is not specifically limited to this.

[0081] For example, a "module" may be a software program, a hardware circuit, or a combination of the two that implements the above functions. The hardware circuit may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor, or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit, and / or other suitable components that support the described functions.

[0082] The embodiments of the present disclosure are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A black box modeling method for common mode conduction interference of power converter based on online identification of impedance parameters, characterized in that: The method comprises: By extracting the broadband scattering parameters of the common-mode conduction interference path of the power converter, the common-mode impedance parameters can be identified online. Combining the online identified common-mode impedance parameters with the online measured current data, a common-mode conducted emission black box model of the power converter is constructed.

2. The method according to claim 1, characterized in that By extracting the broadband scattering parameters of the common-mode conduction interference path of the power converter, the online identification of common-mode impedance parameters includes: Based on the impedance value Z of the three calibration components and the wire i , i=1,2,3 and the corresponding S11 parameter S i， i=1,2,3, construct three equations, solve the equations, and calculate the three calibration coefficients k required for online identification of impedance parameters. i， i=1,2,3; S11 parameter S based on online measurement cm1 With three calibration coefficients k i， i=1,2,3, calculate the online impedance Z of the entire loop loop ; Based on the measured S11 parameter S cm2 and three calibration coefficients k i， i=1,2,3, calculate the external impedance Z of the power converter out ; Based on the online impedance Z of the entire loop loop and the power converter external impedance Z out , calculate the common-mode equivalent impedance Z of the power converter under typical operating conditions con_CM .

3. The method according to claim 2, characterized in that Based on the impedance value Z of the three calibration components and the wire i , i=1,2,3 and the corresponding S11 parameter S i， i=1,2,3, construct three equations, solve the equations, and calculate the three calibration coefficients k required for online identification of impedance parameters. i， i=1,2,3 includes:

4. The method according to claim 3, characterized in that S11 parameter S based on online measurement cm1 With three calibration coefficients k i , i=1,2,3, calculate the online impedance Z of the entire loop loop include:

5. The method according to claim 4, characterized in that Based on the measured S11 parameter S cm2 and three calibration coefficients k i , i=1,2,3, calculate the external impedance Z of the power converter out include:

6. The method according to claim 5, characterized in that Based on the online impedance Z of the entire loop loop and the power converter external impedance Z out , calculate the common-mode equivalent impedance Z of the power converter under typical operating conditions con_CM include: WITH con_CM =Z loop -WITH out 。 7. The method according to claim 6, characterized in that Combining the common-mode impedance parameters identified online with the current data measured online, the common-mode conducted emission black box model of the power converter is constructed, including: Measuring the common-mode conducted interference current I of the power supply cable harness of the power converter CM ; Based on the common mode conducted interference current I CM The online impedance Z of the entire loop loop , calculate the power converter common mode equivalent interference source E th_CM ; Based on the obtained power converter common mode equivalent interference source E th_CM The common-mode equivalent impedance Z of the power converter under typical working conditions con_CM , build its common-mode conducted interference black box model.

8. The method according to claim 7, characterized in that Based on the common mode conducted interference current I CM The online impedance Z of the entire loop loop , calculate the power converter common mode equivalent interference source E th_CM include: E th_CM =Z loop ·I CM 。 9. A black box modeling system for common mode conducted interference of power converter based on online identification of impedance parameters, the system is used to implement the method according to any one of claims 1 to 8, characterized in that: include: Identify and build modules; The identification module is used to perform online identification of common mode impedance parameters by extracting broadband scattering parameters of the common mode conduction interference path of the power converter; The construction module is used to combine the common-mode impedance parameters identified online with the current data measured online to construct a common-mode conducted emission black box model of the power converter.

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