A High-Frequency Filter for a Silicon Carbide Controller and Its Design Method

Abstract

The present invention provides a high-frequency filter for a silicon carbide controller and a design method thereof. The high-frequency filter includes a large and a small racetrack-shaped magnetic ring, X capacitors, Y capacitors, and an integrated filter structure for loading the above-mentioned filtering elements, so as to realize the miniaturization of the filter. The design method specifically includes calculating the frequency of the interference source and the upper limit of the conduction interference voltage transfer gain; determining the initial topology and the optimization sequence; initializing the element values of the filter circuit; performing iterative optimization of the element values by a genetic algorithm; modifying the contemporary optimal element individuals; judging whether the element composition can be optimized; changing the order or topology of the filtering elements; calculating whether each element meets the constraint conditions to obtain the best filter solution. The aim is to solve the problem that the traditional filter design is difficult to effectively cope with the high-frequency electromagnetic interference brought by the silicon carbide controller for new energy vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility (EMC), and particularly relates to a high-frequency filter for a silicon carbide controller and a design method thereof. Background Art

[0002] With the rapid development of new energy vehicles, the problem of vehicle electromagnetic interference (EMI) has become the focus of attention in the industry. New energy vehicles mainly rely on the electric drive system to provide power, and this system usually consists of a power battery, a motor controller, a motor, high-voltage cables, and connectors. Among them, the motor controller is considered to be the main electromagnetic interference source in the electric drive system. During the operation of the power module of the motor controller, rapidly changing voltages and currents are generated. These changes form interference sources through parasitic capacitances and inductances, generating strong electromagnetic interference. These interferences not only affect the normal driving of new energy vehicles but may also spread to the outside through conduction or radiation paths, interfering with surrounding electrical equipment.

[0003] If the transient voltage and current interferences generated by the motor controller fail to be effectively filtered, they will inevitably affect the stability of the vehicle system and reduce its electromagnetic compatibility (EMC). To ensure the safety of the vehicle, new energy vehicle manufacturers have put forward higher EMC standards for the electric drive system. Especially for silicon carbide (SiC) controllers, their higher operating frequencies and power densities require the system to meet more stringent EMC test standards. Although SiC devices have significant advantages in improving system efficiency, they also exacerbate the complexity and intensity of electromagnetic interference. Therefore, traditional filter designs are difficult to effectively address the high-frequency electromagnetic interference problems brought by SiC controllers for new energy vehicles. In view of this problem, there is an urgent need to design an efficient, high-frequency filter suitable for SiC controllers to meet the EMC test requirements of the electric drive system, thereby meeting the electromagnetic compatibility requirements of new energy vehicles.

[0004] In view of this, the present application is proposed. Summary of the Invention

[0005] The present invention provides a high-frequency filter for a silicon carbide controller and a design method thereof, which can at least partially improve the above problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-frequency filter for a silicon carbide controller, comprising: a large magnetic ring, a small magnetic ring, an X capacitor, a Y capacitor, an isolation plastic sheet, and a first copper bar and a second copper bar. Among them, the first copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring and is connected to the positive pole of an external power supply line, and the second copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring and is connected to the negative pole of the external power supply line. An interval space is provided between the large magnetic ring and the small magnetic ring, the isolation plastic sheet is arranged in the interval space, the X capacitor is arranged on the isolation plastic sheet, and the Y capacitor is arranged on the small magnetic ring;

[0008] Among them, the first pin of the X capacitor is connected to the first copper bar, the second pin of the X capacitor is connected to the second copper bar, the first end of the Y capacitor is connected to the first copper bar and the second copper bar, the second end of the Y capacitor is grounded, and the isolation plastic sheet is configured to separate the positive and negative wires.

[0009] The present invention also provides a design method for a high-frequency filter for a silicon carbide controller, which includes:

[0010] Calculating the interference frequency range and the upper limit of the conduction interference voltage transfer gain of the high-frequency filter for the silicon carbide controller as described in any one of the above;

[0011] Calculating the component parameters of the high-frequency filter for the silicon carbide controller according to the upper limit of the conduction interference voltage transfer gain, where the component parameters include a large magnetic ring, a small magnetic ring, an X capacitor, a Y capacitor, a first copper bar and a second copper bar;

[0012] Using the genetic algorithm GA to optimize the component parameters of the high-frequency filter for the silicon carbide controller;

[0013] Calculating the insertion loss constraint according to the optimized component parameters, determining the best filtering scheme, and designing a high-frequency filter for the silicon carbide controller.

[0014] In summary, the high-frequency filter for the silicon carbide controller includes a large and a small amorphous nanocrystalline magnetic ring, an X capacitor, a Y capacitor, and an integrated filter structure for loading the above-mentioned filtering components, realizing the miniaturization of the filter. This high-frequency filter solves the problem that the traditional filter design is difficult to effectively cope with the high-frequency electromagnetic interference brought by the silicon carbide controller for new energy vehicles.

[0015] Its design method includes calculating the frequency of the interference source (silicon carbide controller) and the upper limit of the conduction interference voltage transfer gain; determining the initial topology and optimization sequence; initializing the element values of the filter circuit; performing iterative optimization of the element values using the genetic algorithm; modifying the contemporary optimal element individuals; determining whether the element composition can be optimized; changing the filter element order or topology; and calculating whether each element meets the constraints to obtain the best filter solution. This method takes the minimum size of the filter circuit as the optimization design goal, and the minimum insertion loss and transmission efficiency as the design constraints, automatically selects the optimal topology and component parameters of the filter according to the source impedance and load impedance, avoiding the filter resonance phenomenon and over-design problems caused by not considering the source impedance. Description of the Drawings

[0016] Figure 1 is a schematic diagram of the overall structure of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0017] Figure 2 is a top view of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0018] Figure 3 is a bottom view of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of the positive and negative copper bars of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0020] Figure 5 is a schematic diagram of the assembled magnetic core, X capacitor, and Y capacitor frame structure of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0021] Figure 6 is a schematic diagram of the used racetrack-shaped magnetic core of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0022] Figure 7 is a schematic flowchart of the design method of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention;

[0023] Figure 8 are the inductance magnitudes and impedance values of the amorphous nanocrystalline racetrack-shaped magnetic ring selected for the high-frequency filter for the silicon carbide controller at various frequencies;

[0024] Figure 9 is a comparison diagram of the interference voltage after the high-frequency filter for the silicon carbide controller is loaded into the controller circuit and the national standard GB / T 18387-2017;

[0025] Figure 10The comparison chart of the interference voltage after the high-frequency filter for the silicon carbide controller is loaded into the controller circuit, the filter without loading, the conventional filter, and the national standard GB / T 18387-2017;

[0026] Figure 11 It is the copper busbar parameter diagram of a design method of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention. Specific embodiments

[0027] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Reference Figures 1 to 6 As shown, the first embodiment of the present invention discloses a high-frequency filter for a silicon carbide controller, which includes: a small magnetic ring 1, a large magnetic ring 2, an X capacitor 4, a Y capacitor 5, an isolation plastic sheet 6, and a first copper busbar 31 and a second copper busbar 32. Among them, the first copper busbar 31 passes through the ring bodies of the small magnetic ring 1 and the large magnetic ring 2 and is connected to the positive pole of the external power supply line, and the second copper busbar 32 passes through the ring bodies of the small magnetic ring 1 and the large magnetic ring 2 and is connected to the negative pole of the external power supply line. An interval space is provided between the small magnetic ring 1 and the large magnetic ring 2, the isolation plastic sheet 6 is arranged in the interval space, the X capacitor 4 is arranged on the isolation plastic sheet 6, and the Y capacitor 5 is arranged on the large magnetic ring 2;

[0029] Among them, the first pin of the X capacitor 4 is connected to the first copper busbar 31, the second pin of the X capacitor 4 is connected to the second copper busbar 32, the first end of the Y capacitor 5 is connected to the first copper busbar 31 and the second copper busbar 32, the second end of the Y capacitor 5 is grounded, and the isolation plastic sheet 6 is configured to separate the positive and negative wires.

[0030] Preferably, both the small magnetic ring 1 and the large magnetic ring 2 are made of high magnetic performance materials.

[0031] Specifically, in this embodiment, the high-frequency filter for the silicon carbide controller includes a large and a small amorphous nanocrystalline magnetic ring, an X capacitor 4, a Y capacitor 5, and two groups of copper busbars. The small magnetic ring 1 and the large magnetic ring 2 are respectively connected to the two groups of copper busbars for connecting the positive and negative poles of the power supply line. The magnetic ring material is an amorphous nanocrystalline material with high magnetic permeability, which is suitable for suppressing high-frequency common-mode interference; there is an interval space between the large and small magnetic rings, and a protruding plastic sheet is arranged in this space for separating the positive and negative wires, weakening the magnetic field coupling, and enhancing the electromagnetic compatibility; the X capacitor 4 is fixed on the small platform of the plastic sheet, and the two pins are respectively connected to suppress differential-mode interference, and the Y capacitor 5 is grounded through the grounding hole to the copper busbar.

[0032] A small platform for fixing the X-capacitor 4 is designed on the plastic sheet. The pins of the X-capacitor 4 are respectively connected to the copper bars of the positive and negative electrodes, optimizing the stability of the electrical connection. One end of the Y-capacitor 5 is connected to the copper bar, and the other end is grounded through the grounding hole, reducing the leakage current and improving the electromagnetic compatibility. Among them, the large and small magnetic rings are made of amorphous nanocrystalline materials, with high magnetic permeability and low loss characteristics, effectively suppressing the high-frequency common-mode current generated during the operation of the silicon carbide controller.

[0033] In this embodiment, the high-frequency filter for the silicon carbide controller is composed of filter magnetic rings of different sizes, two groups of copper bars, an isolation plastic sheet 6, and a filter circuit. The large and small magnetic rings pass through the two groups of copper bars and are respectively used to connect the positive and negative electrodes of the power line. They have high magnetic permeability and can effectively suppress high-frequency common-mode interference. There is a spaced space between the two magnetic rings, with a protruding plastic sheet built-in, used to separate the positive and negative wires, weakening the magnetic field coupling between them and enhancing the electromagnetic compatibility; at the same time, the plastic sheet can be used as a support when the filter assembles the X-capacitor 4. The large magnetic ring 2, through which two groups of copper bars pass and are respectively connected to the positive and negative electrodes of the power line, can effectively suppress high-frequency common-mode interference. The material is a nanocrystalline material with high magnetic permeability, suitable for high-frequency working environments. The small magnetic ring 1, with a material of nanocrystalline material with high magnetic permeability, is suitable for high-frequency working environments. It is applicable to the suppression of common-mode current under high-frequency operation. And a protruding plastic sheet is arranged in the spaced space between the large and small magnetic rings to separate the positive and negative wires, reducing the magnetic field coupling and improving the electromagnetic compatibility of the system. The small platform above the plastic sheet is used for fixing the X-capacitor.

[0034] Please refer to Figures 7 to 11 , the second embodiment of the present invention provides a design method for a high-frequency filter for a silicon carbide controller, which includes:

[0035] Calculate the interference frequency range and the upper limit of the conduction interference voltage transfer gain of the high-frequency filter for the silicon carbide controller as described in any one of the above;

[0036] Calculate the component parameters of the high-frequency filter for the silicon carbide controller according to the upper limit of the conduction interference voltage transfer gain, where the component parameters include the small magnetic ring 1, the large magnetic ring 2, the X-capacitor 4, the Y-capacitor 5, the first copper bar 31, and the second copper bar 32;

[0037] Use the genetic algorithm GA for the component parameters of the high-frequency filter for the silicon carbide controller;

[0038] Calculate the insertion loss constraint according to the optimized component parameters, determine the best filtering scheme, and design the high-frequency filter for the silicon carbide controller.

[0039] In this embodiment, the specific steps of the design method include: 1. calculating the frequency of the interference source (silicon carbide controller) and the upper limit of the conduction interference voltage transfer gain; 2. determining the initial topology and the optimization sequence; 3. initializing the element values of the filter circuit; 4. performing iterative optimization of the element values by genetic algorithm; 5. modifying the contemporary optimal element individuals; 6. judging whether the element composition can be optimized; 7. changing the filter element order or topology; 8. calculating whether each element meets the constraint conditions; 9. determining the optimal filter scheme.

[0040] Briefly speaking, it is to calculate the interference frequency range of the silicon carbide controller and the upper limit of the conduction interference voltage transfer gain; determine the initial topology and component layout of the filter; use genetic algorithm to iteratively optimize the component parameters, including the configuration of large magnetic rings, small magnetic rings, X capacitors and Y capacitors; correct the optimization results, adjust the element order and topology, and calculate whether each element meets the insertion loss and electromagnetic compatibility constraints; determine the optimal filter design scheme by calculating the insertion loss. Among them, the optimization process considers the source impedance and the load impedance, avoids the filter resonance phenomenon, and ensures that the electromagnetic compatibility performance meets the requirements. By optimizing the filter volume, reducing the number of components and the space occupation, the miniaturized design of the filter is realized, which is suitable for the high-frequency working environment of the silicon carbide controller.

[0041] Preferably, calculating the interference frequency range and the upper limit of the conduction interference voltage transfer gain of the high-frequency filter for the silicon carbide controller specifically includes:

[0042] According to the formula: calculate the upper limit of the conduction interference voltage transfer gain, where Tranemi is the upper limit of the conduction interference voltage transfer gain, is the line impedance stabilization network voltage, is the conduction interference equivalent voltage.

[0043] In this embodiment, calculate the upper limit of the system conduction interference transfer gain , and calculate the upper limit of the conduction interference voltage transfer gain according to the above formula to ensure that the system conduction interference is lower than the limit specified by the EMC standard.

[0044] Preferably, calculating the initial parameters of the components of the high-frequency filter for the silicon carbide controller according to the upper limit of the conduction interference voltage transfer gain specifically includes:

[0045] Assume that the capacitance values are equal, the total capacitance is equal to the maximum value determined by the maximum leakage current, and calculate the minimum inductance value and the minimum number of inductors Lmin(i) from the upper limit of the conduction interference voltage transfer gain at each frequency.

[0046] Preferably, calculating the initial parameters of the components of the high-frequency filter for the silicon carbide controller according to the upper limit of the conduction interference voltage transfer gain is specifically as follows:

[0047] Define the filter volume as: , where i represents the number of magnetic cores, i≥Lmin(i), Lmin(i) is the minimum number of inductors, j is the number of X capacitors, k is the number of Y capacitors, j, k≥0, is the volume of the magnetic core, is the volume of the X capacitor, is the volume of the Y capacitor;

[0048] Determine the minimum cross-sectional area S of the first copper bar and the second copper bar according to the current level;

[0049] Assume the width of the copper bar is B and the thickness is A, and calculate the thickness c of the epoxy resin sprayed on the surface of the copper bar according to the formula c = U / 2000, where U is the working voltage of the filter;

[0050] Determine the distance E between the first copper bar and the second copper bar;

[0051] Define the relationship between the volume of the magnetic core and the inductance value. The inductance value of the magnetic core is expressed as: , where L is the inductance of the magnetic core coil, F is the cross-section of the magnetic core, l is the average length of the magnetic path of the magnetic core, is the relative permeability of the magnetic core, is a function of the frequency f, , is the minimum inductance value;;

[0052] Substitute the formulas and into the inductance value expression of the magnetic core to obtain , , where D is the height of the racetrack magnetic core, H is the thickness of the racetrack magnetic core, R is the inner diameter of the curved surface of the racetrack magnetic core, R1 is the outer diameter of the curved surface of the racetrack magnetic core, and G is the straight length of the racetrack magnetic core;

[0053] According to the formula calculate the volume of a single magnetic core.

[0054] Preferably, the dimensional requirements for the first copper bar and the second copper bar are: .

[0055] In this embodiment, calculate the required minimum number of magnetic cores, X capacitors, Y capacitors and the magnetic core size according to the upper limit of the conduction interference voltage transfer gain. Specifically:

[0056] First, define the filter volume: , i, j, and k are the numbers of magnetic rings, X capacitors, and Y capacitors, and 、 represent the volumes of the magnetic ring, X capacitor, and Y capacitor respectively.

[0057] Please refer to Figure 11 . Secondly, conduct the copper busbar design: According to the current rating, the minimum cross-sectional area S of the copper busbar is determined by the electrical manual; assuming the width of the copper busbar is B and the thickness is A, determine the thickness c of the epoxy resin sprayed on the surface of the copper busbar according to the following formula, , where U is the operating voltage (V) of the filter; determine the distance E between two copper busbars; the copper busbar dimensions meet the requirements: .

[0058] Finally, define the relationship between the volume of the magnetic ring and the inductance value. The inductance value of the magnetic ring can be expressed as: , where L is the inductance (H) of the magnetic ring coil, F is the cross-sectional area (cm²) of the magnetic ring, L is the average length (cm) of the magnetic ring, and μ is the relative permeability of the magnetic ring, is a function of the frequency f.

[0059] Substitute , into , and obtain: ; therefore, .

[0060] In summary, the volume of the magnetic ring can be calculated using the formula: .

[0061] Preferably, use the genetic algorithm GA to optimize the component parameters of the high-frequency filter for the silicon carbide controller, specifically:

[0062] For the cascade network formed by the mth and (m + 1)th elements in the filter circuit of the high-frequency filter, the calculation formula for its transmission matrix is: , where N1, N2, N3, and N4 are specific parameters in the transmission matrix;

[0063] Define the mathematical expression of matrix M as: , where det(N) is the value of the determinant of matrix N;

[0064] The constraint conditions for each element in matrix M are: , and use this as the preset constraint condition to perform iterative optimization on the filter topology structure;

[0065] Use the genetic algorithm to perform iterative evolution on the topology structures of the magnetic ring, X capacitor, and Y capacitor;

[0066] When it is determined that the transmission parameter matrix of a component has an impact on the transmission parameter matrix of the entire filter that is less than a preset value, the component is removed from the filter;

[0067] When it is determined that the transmission parameters of two components in parallel or in series are less than a preset value for the transmission parameter matrix of the entire filter, the two components are connected in parallel or in series;

[0068] Under the condition of meeting the preset constraint conditions, according to the formula Compare and calculate the volume of the component before and after removal, parallel connection, and series connection;

[0069] If , then continue with topology optimization according to the result of the latest iteration;

[0070] If , perform the next calculation according to the result of the previous iteration.

[0071] In this embodiment, the GA algorithm is used to optimize the filter topology, order, and element values.

[0072] The transmission parameter matrix of the EMI filter is crucial, which determines the performance of the filtering circuit and its impact on the touch current and leakage current. This matrix is obtained by multiplying the transmission matrices of each unit in the filtering circuit. For the cascade network formed by the m-th and (m + 1)-th elements in the filtering circuit, its transmission matrix is calculated as follows: .

[0073] After defining the number of magnetic rings that meet the requirements and the volume of each magnetic ring, as well as the number of X capacitors and Y capacitors according to the requirements, the genetic algorithm is used to iteratively evolve the topology of the magnetic rings, X capacitors, and Y capacitors. If the transmission parameter matrix of a component has little impact on the transmission parameter matrix of the entire filter, then the contribution of this component to suppressing interference is small and it can be removed from the filter; if the transmission parameters of two components in parallel or in series have little impact on the transmission parameter matrix of the entire filter, then the two components can be considered to be connected in parallel or in series. Under the condition of meeting the existing constraints, according to Compare and calculate the volume of the component before and after removal, parallel connection, and series connection to further reduce the volume of the filter and achieve miniaturization of the filter.

[0074] Define the matrix M as: , and make each element in M satisfy the following constraints: .

[0075] Preferably, calculate the insertion loss constraint according to the optimized component parameters, specifically:

[0076] Apply the insertion loss constraint to the filter, estimate the insertion loss of the filter using the T-parameters, and the T-parameter matrices of the series inductor and the parallel capacitor are: , where ZLi is the inductance impedance and ZCj is the capacitance impedance;

[0077] Calculate the impedance of the magnetic ring. The calculation formula is: ;

[0078] Calculate the impedance of the capacitor. The calculation formula is: , where L is the equivalent parasitic inductance of the capacitor, and R C is the equivalent parasitic capacitance of the capacitor;

[0079] Obtain the T-parameter matrix of the filter as: , where T Li is the T-parameter matrix corresponding to the inductor in the circuit, and T Ci is the T-parameter matrix corresponding to the capacitor;

[0080] The calculation formula for the insertion loss of the filter is: , where Z S is the system source impedance, and Z L is the system load impedance;

[0081] Use the formula to calculate the target insertion loss of the filter and verify whether the requirement is met. Among them, is the target insertion loss of the filter, is the amplitude of the conducted interference voltage of the silicon carbide controller, is the limit value required by the standard, ;

[0082] Split the insertion loss into the CM insertion loss and the DM insertion loss , and combine each constraint into a non-linear constraint through the formulas and , and determine whether the preset constraint conditions are met. Among them, b1 is the criterion for whether the CM insertion loss meets the constraint conditions, and b2 is the criterion for whether the DM insertion loss meets the constraint conditions;

[0083] If so, , obtain the optimal filter scheme;

[0084] If not, continue to optimize the filter parameter components using the genetic algorithm GA.

[0085] In this embodiment, for the calculation of the insertion loss constraint, after satisfying the above conditions, the insertion loss constraint of the filter is:

[0086] Estimate the insertion loss of the filter using the T-parameters: The T-parameter matrices of the series inductor and the parallel capacitor are as follows: , Z Li and Z Cj are the inductance and capacitance impedances respectively. The impedance of the magnetic core can be calculated by the following formula: ; The impedance of the capacitor can be calculated by the following formula: , L C and R C are the equivalent parasitic inductance and equivalent parasitic capacitance of the capacitor respectively.

[0087] The T-parameter matrix of the filter is: , then the calculation method of the insertion loss of the filter is: Z S is the system source impedance, and Z L is the system load impedance.

[0088] Adopt formula to calculate the target insertion loss of the filter and verify whether the requirements are met. : The target insertion loss of the filter; : The amplitude of the conducted interference voltage of the silicon carbide controller; : The limit value required by the standard. The requirement is: .

[0089] Insertion constraint loss calculation: When implementing the filter optimization design algorithm, the insertion loss is split into the CM insertion loss and the DM insertion loss , and each constraint is combined into a non-linear constraint Φ through formula and formula . When the constraint conditions are not met, Φ > 0, and when the constraint conditions are met, Φ = 0; where, b1 and b2 are the criteria for whether the CM insertion loss and the DM insertion loss meet the constraint conditions respectively. Since the insertion loss is a function of frequency, when comparing, m frequency points are selected within the frequency range as needed, and the insertion losses at these frequency points are compared and calculated.

[0090] Finally, design the integrated filter according to the output optimal filter solution. According to the optimal filter topology solution determined by the filter design method for the silicon carbide controller described above, confirm the selected magnetic core, X capacitor, and Y capacitor, design the filter structure, and further realize the miniaturization of the filter.

[0091] In summary, compared with the existing filters, the high-frequency filter for the silicon carbide controller has the following characteristics: 1. Special grooves are designed at both ends of the filter. The grooves are used to assemble the racetrack-shaped magnetic core, and after the assembly is completed, it is sealed by potting to ensure the stable installation of the magnetic core, while improving its anti-vibration and environmental tolerance capabilities and enhancing the reliability of long-term use. 2. Two copper bars penetrate through two magnetic cores and are respectively connected to the positive and negative wires to achieve efficient current conduction. The design of the copper bars ensures that the filter has excellent conductivity when dealing with high currents, while reducing energy loss and improving the overall working efficiency of the system. 3. An isolating plastic sheet with protrusions is arranged between the large and small magnetic rings to effectively separate the positive and negative wires and reduce the magnetic field coupling between them. This design significantly enhances the electromagnetic compatibility (EMC) of the system and ensures the effect of suppressing electromagnetic interference (EMI) in a high-frequency working environment. 4. A small platform is designed above the plastic sheet, which is specifically used to fix the X capacitor. The pins of the two X capacitors are respectively connected to the copper bars of the positive and negative poles, optimizing the installation position of the capacitor, simplifying the assembly process, and improving the stability of the electrical connection. 5. Grounding holes are opened on the outer sides of the two copper bars. One end pin of the Y capacitor is connected to the copper bar on the corresponding side, and the other end is grounded through the grounding hole. Such a grounding design not only effectively reduces the leakage current but also further improves the electromagnetic compatibility performance of the filter, ensuring the safety of system operation. 6. Screw holes are opened at the four corners of the filter for fixing the filter body. This design ensures that the filter can be firmly installed in various application environments, effectively resisting vibration and mechanical stress, and extending the service life of the equipment.

[0092] The above is the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A high-frequency filter for a silicon carbide controller, characterized in that, Comprising: A large magnetic ring, a small magnetic ring, an X capacitor, a Y capacitor, an isolation plastic sheet, and a first copper bar and a second copper bar. Wherein, the first copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring and is connected to the positive pole of an external power supply line, and the second copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring and is connected to the negative pole of the external power supply line. An interval space is provided between the large magnetic ring and the small magnetic ring, the isolation plastic sheet is disposed in the interval space, the X capacitor is disposed on the isolation plastic sheet, and the Y capacitor is disposed on the small magnetic ring; Wherein, a first pin of the X capacitor is connected to the first copper bar, a second pin of the X capacitor is connected to the second copper bar, a first end of the Y capacitor is connected to the first copper bar and the second copper bar, a second end of the Y capacitor is grounded, and the isolation plastic sheet is configured to separate positive and negative wires; The initial parameters of the components of the high-frequency filter for a silicon carbide controller are calculated based on the upper limit of the transfer gain of the conducted interference voltage, specifically: Define the filter volume as: , where i represents the number of magnetic rings, i ≥ Lmin(i), Lmin(i) is the minimum number of inductors, j is the number of X capacitors, k is the number of Y capacitors, j, k ≥ 0, is the volume of the magnetic ring, is the volume of the X capacitor, is the volume of the Y capacitor; Determine the minimum cross-sectional area S of the first copper bar and the second copper bar according to the current level; Assume the width of the copper bar is B and the thickness is A, and calculate the thickness c of the epoxy resin sprayed on the copper bar surface according to the formula c = U / 2000, where U is the operating voltage of the filter; Determine the distance E between the first copper bar and the second copper bar; Define the relationship between the toroid volume and the inductance value. The inductance value of the toroid is expressed as: , where L is the inductance of the toroid coil, F is the cross-sectional area of the toroid, l is the average length of the toroid magnetic path, is the relative magnetic permeability of the toroid, is a function of the frequency f, , is the minimum inductance value; Substitute the formulas and into the expression of the inductance value of the magnetic ring, and we get , , where D is the height of the racetrack magnetic ring, H is the thickness of the racetrack magnetic ring, R is the inner diameter of the curved surface of the racetrack magnetic ring, R1 is the outer diameter of the curved surface of the racetrack magnetic ring, and G is the straight length of the racetrack magnetic ring; According to the formula the volume of a single magnetic ring is calculated; Use the genetic algorithm GA to optimize the component parameters of the high-frequency filter for a silicon carbide controller, specifically: For the cascade network formed by the m-th and (m + 1)-th elements in the filter circuit of the high-frequency filter, the calculation formula for its transmission matrix is: , where N1, N2, N3, and N4 are specific parameters in the transmission matrix; The mathematical expression for defining matrix M is: , where det(N) is the value of the determinant of matrix N; The constraint conditions for each element in matrix M are as follows: Using this as the preset constraint condition, the filter topology is iteratively optimized; Use the genetic algorithm to perform topological structure iterative evolution on the magnetic ring, X capacitor, and Y capacitor; When it is judged that the influence of the transmission parameter matrix of a component on the transmission parameter matrix of the entire filter is less than a preset value, remove it from the filter; When it is judged that the influence of the transmission parameters after two components are connected in parallel or in series on the transmission parameter matrix of the entire filter is less than a preset value, connect the two components in parallel or in series; Under the condition of meeting the preset constraints, according to the formula Compare and calculate the volume of the component before and after removal, parallel connection, and series connection; If , continue the topology optimization according to the results of the latest iteration; If , perform the next calculation based on the result of the previous iteration.

2. The high-frequency filter for a silicon carbide controller according to claim 1, wherein Both the large magnetic ring and the small magnetic ring are made of high magnetic performance materials.

3. A design method for a high-frequency filter used in a silicon carbide controller, characterized in that, Comprising: Calculate the interference frequency range and the upper limit of the transfer gain of the conducted interference voltage of the high-frequency filter for a silicon carbide controller according to any one of claims 1 to 2; Calculate the initial parameters of the components of the high-frequency filter for a silicon carbide controller according to the upper limit of the transfer gain of the conducted interference voltage; Use the genetic algorithm GA to optimize the component parameters of the high-frequency filter for a silicon carbide controller; Calculate the insertion loss constraint according to the optimized component parameters, determine the optimal filtering scheme, and design a high-frequency filter for a silicon carbide controller.

4. The design method of a high-frequency filter for a silicon carbide controller according to claim 3, wherein, Calculate the interference frequency range and the upper limit of the transfer gain of the conducted interference voltage of the high-frequency filter for a silicon carbide controller as described above, specifically: According to the formula: Calculate the upper limit of the conducted interference voltage transfer gain. Among them, Tranemi is the upper limit of the conducted interference voltage transfer gain, is the line impedance stabilization network voltage, is the conducted interference equivalent voltage.

5. The design method of a high-frequency filter for a silicon carbide controller according to claim 4, characterized in that, Calculate the initial parameters of the components of the high-frequency filter for a silicon carbide controller according to the upper limit of the transfer gain of the conducted interference voltage, specifically: Assuming that the capacitance values are equal, the total capacitance is equal to the maximum value determined by the maximum leakage current, and the minimum inductance value is calculated from the upper limit of the transfer gain of the interference voltage at each frequency. and the minimum number of inductors Lmin(i).

6. The design method of a high-frequency filter for a silicon carbide controller according to claim 3, characterized in that, The dimensional requirements for the first copper bar and the second copper bar are as follows: .

7. A design method of a high-frequency filter for a silicon carbide controller according to claim 3, characterized in that, Calculate the insertion loss constraint according to the optimized component parameters, specifically: Insertion loss constraints are imposed on the filter, and the insertion loss of the filter is estimated using the T-parameters. The T-parameter matrices of the series inductor and the parallel capacitor are as follows: , where Z Li is the inductor impedance and Z Cj is the capacitor impedance; Calculate the impedance of the magnetic core, and the calculation formula is: ; Calculate the impedance of the capacitor, and the calculation formula is: , where L C is the equivalent parasitic inductance of the capacitor, and R C is the equivalent parasitic capacitance of the capacitor; The T-parameter matrix of the filter is obtained as follows: , where T li is the T-parameter matrix corresponding to the inductor in the circuit, and T ci is the T-parameter matrix corresponding to the capacitor; The calculation formula for the insertion loss of the filter is as follows: , where Z S is the system source impedance, and Z L is the system load impedance; Use the formula to calculate the target insertion loss of the filter and verify whether the requirements are met. Among them, is the target insertion loss of the filter, is the amplitude of the conducted interference voltage of the silicon carbide controller, is the limit value required by the standard, ; Split the insertion loss into the CM insertion loss and the DM insertion loss , and combine each constraint through the formulas and into a non - linear constraint , and determine whether the preset constraint conditions are met. Among them, b1 is the criterion for whether the CM insertion loss meets the constraint conditions, and b2 is the criterion for whether the DM insertion loss meets the constraint conditions; If so, the optimal filter solution is obtained; If not, continue to use the genetic algorithm GA to further optimize the filter parameter components.

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