High-frequency filter for silicon carbide controller and design method thereof

Abstract

The invention provides a high-frequency filter for a silicon carbide controller and a design method of the high-frequency filter, the high-frequency filter comprises a large runway type magnetic ring, a small runway type magnetic ring, an X capacitor, a Y capacitor and an integrated filter structure for loading the filter elements, and the miniaturization of the filter is realized. The design method specifically comprises the following steps: calculating the frequency of an interference source and a conducted interference voltage transfer gain upper limit; determining an initial topological structure and an optimization sequence; initializing the element value of each element of the filter circuit; carrying out element value iterative optimization by a genetic algorithm; modifying a contemporary optimal element individual; judging whether the element composition can be optimized or not; changing the sequence or topological structure of filtering elements; and calculating whether each element meets the optimal filter scheme of the constraint condition. The invention aims to solve the problem that the traditional filter design is difficult to effectively deal with high-frequency electromagnetic interference caused by a silicon carbide controller for a new energy vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility (EMC), and in particular 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 electromagnetic interference (EMI) problem of the whole vehicle has become the focus of attention in the industry. New energy vehicles are mainly powered by electric drive systems, which are usually composed of power batteries, motor controllers, motors, high-voltage cables and connectors. Among them, the motor controller is considered to be the main source of electromagnetic interference in the electric drive system. The power module of the motor controller will generate rapidly changing voltage and current during operation. These changes form interference sources through parasitic capacitance and parasitic inductance, generating strong electromagnetic interference. These interferences will 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 interference generated by the motor controller is not effectively filtered, it will inevitably affect the stability of the vehicle system and reduce its electromagnetic compatibility (EMC). In order to ensure the safety of the vehicle, new energy vehicle manufacturers have put forward higher EMC standards for electric drive systems, especially for silicon carbide (SiC) controllers, whose higher operating frequency and power density require the system to meet more stringent EMC test standards. Although SiC devices have significant advantages in improving system efficiency, they also increase the complexity and intensity of electromagnetic interference. Therefore, traditional filter design has been difficult to effectively deal with the high-frequency electromagnetic interference problem caused by silicon carbide controllers for new energy vehicles. In response to this problem, there is an urgent need to design an efficient, high-frequency filter suitable for silicon carbide controllers to meet the EMC test requirements of electric drive systems, thereby meeting the electromagnetic compatibility requirements of new energy vehicles.

[0004] In view of this, this application is filed. 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-mentioned problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions: 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, wherein the first copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring to be connected to the positive pole of an external power line, the second copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring to be connected to the negative pole of the external power line, a spacing space is provided between the large magnetic ring and the small magnetic ring, the isolation plastic sheet is arranged in the spacing space, the X capacitor is arranged on the isolation plastic sheet, and the Y capacitor is arranged on the small magnetic ring; 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 electrode lines.

[0007] The present invention also provides a design method for a high-frequency filter for a silicon carbide controller, which comprises: Calculate the interference frequency range and the upper limit of the conducted interference voltage transfer gain of the high-frequency filter for the silicon carbide controller as described in any one of the above items; Calculating the component parameters of the high-frequency filter for the silicon carbide controller according to the upper limit of the conducted interference voltage transfer gain, wherein 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; Using a genetic algorithm GA to optimize component parameters of the high-frequency filter for the silicon carbide controller; The insertion loss constraint is calculated based on the optimized component parameters, the optimal filtering scheme is determined, and a high-frequency filter for the silicon carbide controller is designed.

[0008] 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 filter elements, thereby realizing the miniaturization of the filter. The high-frequency filter solves the problem that traditional filter designs are difficult to effectively deal with the high-frequency electromagnetic interference caused by the silicon carbide controller for new energy vehicles.

[0009] The design method includes calculating the frequency of the interference source (silicon carbide controller) and the upper limit of the conducted interference voltage transfer gain; determining the initial topology and optimization order; initializing the element values ​​of each component of the filter circuit; iteratively optimizing the element values ​​using genetic algorithms; modifying the optimal element individuals of the current era; judging whether the element composition can be optimized; changing the filter element order or topology; and calculating whether each element meets the constraints for the optimal filter solution. This method takes the minimum size of the filter circuit as the optimization design goal, takes the minimum insertion loss and transmission efficiency as the design constraints, and 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It 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; Figure 2 is a top view of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention; Figure 3 is a bottom view of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention; Figure 4 It 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; Figure 5 It 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; Figure 6 Schematic diagram of a racetrack-shaped magnetic core used in a high-frequency filter for a silicon carbide controller provided in an embodiment of the present invention; Figure 7 It is a flow chart of a design method of a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention; Figure 8 The inductance and impedance values ​​of the amorphous nanocrystalline racetrack-shaped magnetic ring selected for the high-frequency filter of the silicon carbide controller at various frequencies; Fig. 9 A comparison chart of the interference voltage after the high-frequency filter of the silicon carbide controller is loaded into the controller circuit and the national standard GB / T 18387-2017; Fig.10 A comparison chart of the interference voltage after the high-frequency filter for the silicon carbide controller is loaded into the controller circuit and the interference voltage after the filter is loaded, the conventional filter is loaded, and the national standard GB / T 18387-2017; Fig.11 It is a copper busbar parameter diagram of a design method for a high-frequency filter for a silicon carbide controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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.

[0012] refer to 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 bar 31 and a second copper bar 32, wherein the first copper bar 31 passes through the ring bodies of the small magnetic ring 1 and the large magnetic ring 2 to be connected to the positive pole of the external power line, the second copper bar 32 passes through the ring bodies of the small magnetic ring 1 and the large magnetic ring 2 to be connected to the negative pole of the external power line, a spacing space is provided between the small magnetic ring 1 and the large magnetic ring 2, the isolation plastic sheet 6 is arranged in the spacing 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; The first pin of the X capacitor 4 is connected to the first copper bar 31, the second pin of the X capacitor 4 is connected to the second copper bar 32, the first end of the Y capacitor 5 is connected to the first copper bar 31 and the second copper bar 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 lines.

[0013] Preferably, the small magnetic ring 1 and the large magnetic ring 2 are both made of high magnetic performance materials.

[0014] 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 bars. The small magnetic ring 1 and the large magnetic ring 2 are respectively connected to the two groups of copper bars for connecting the positive and negative poles of the power 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 a spacing space between the large and small magnetic rings, and a protruding plastic sheet is arranged in the space to separate the positive and negative poles, weaken the magnetic field coupling, and enhance the electromagnetic compatibility; the X capacitor 4 is fixed on a 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 to the copper bar through the grounding hole.

[0015] The plastic sheet is designed with a small platform for fixing the X capacitor 4, and the pins of the X capacitor 4 are respectively connected to the copper busbars of the positive and negative electrodes, which optimizes the stability of the electrical connection. One end of the Y capacitor 5 is connected to the copper busbar, and the other end is grounded through the grounding hole to reduce leakage current and improve electromagnetic compatibility. Among them, the large and small magnetic rings are made of amorphous nanocrystalline materials, which have high magnetic permeability and low loss characteristics, and effectively suppress the high-frequency common-mode current generated during the operation of the silicon carbide controller.

[0016] 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, which are used to connect the positive and negative poles of the power line respectively. They have high magnetic permeability and can effectively suppress high-frequency common-mode interference. A spacing space is provided between the two magnetic rings, and a protruding plastic sheet is built in to separate the positive and negative poles, weaken the magnetic field coupling between the two, and enhance electromagnetic compatibility; at the same time, the plastic sheet can be used as a support when the filter is assembled with the X capacitor 4. The large magnetic ring 2 passes through two groups of copper bars in the ring, which are respectively connected to the positive and negative poles of the power line, and can effectively suppress high-frequency common-mode interference. The material is a nanocrystalline material with high magnetic permeability, which is suitable for high-frequency working environment. The small magnetic ring 1 is made of a nanocrystalline material with high magnetic permeability, which is suitable for high-frequency working environment. It is suitable for common-mode current suppression under high-frequency operation. And a protruding plastic sheet is provided in the spacing space between the large and small magnetic rings to separate the positive and negative poles, reduce magnetic field coupling, and improve the electromagnetic compatibility of the system. The small platform above the plastic sheet is used to fix the X capacitor.

[0017] See also Figures 7 to 11 A second embodiment of the present invention provides a method for designing a high-frequency filter for a silicon carbide controller, which includes: Calculate the interference frequency range and the upper limit of the conducted interference voltage transfer gain of the high-frequency filter for the silicon carbide controller as described in any one of the above items; Calculating the component parameters of the high-frequency filter for the silicon carbide controller according to the upper limit of the conducted interference voltage transfer gain, wherein the component parameters include a small magnetic ring 1, a large magnetic ring 2, an X capacitor 4, a Y capacitor 5, a first copper bar 31 and a second copper bar 32; Component parameters of the high frequency filter used in the silicon carbide controller using a genetic algorithm GA; The insertion loss constraint is calculated based on the optimized component parameters, the optimal filtering scheme is determined, and a high-frequency filter for the silicon carbide controller is designed.

[0018] 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 conducted interference voltage transfer gain; 2. determining the initial topology and optimization order; 3. initializing the element values ​​of each component of the filter circuit; 4. performing iterative optimization of the element values ​​using a genetic algorithm; 5. modifying the contemporary optimal element individual; 6. determining whether the element composition can be optimized; 7. changing the filter element order or topology; 8. calculating whether each element meets the constraints; 9. determining the optimal filter solution.

[0019] In simple terms, the interference frequency range and the upper limit of the conducted interference voltage transfer gain of the silicon carbide controller are calculated; the initial topology and component layout of the filter are determined; the component parameters are iteratively optimized using a genetic algorithm, including the configuration of large magnetic rings, small magnetic rings, X capacitors, and Y capacitors; the optimization results are corrected, the component sequence and topology are adjusted, and each component is calculated to see whether it meets the insertion loss and electromagnetic compatibility constraints; the insertion loss is calculated to determine the best filter design. The optimization process takes into account the source impedance and load impedance, avoids the resonance of the filter, and ensures that the electromagnetic compatibility performance meets the requirements. By optimizing the filter volume, reducing the number of components and space occupancy, the miniaturized design of the filter is achieved, which is suitable for the high-frequency working environment of the silicon carbide controller.

[0020] Preferably, the interference frequency range and the upper limit of the conducted interference voltage transfer gain of the high-frequency filter for the silicon carbide controller are calculated as follows: According to the formula: Calculate the upper limit of the conducted interference voltage transfer gain, where Tranemi is the upper limit of the conducted interference voltage transfer gain, Stabilize network voltage for line impedance, is the conducted interference equivalent voltage.

[0021] In this embodiment, the filter cascade matrix is ​​defined as: , calculate the upper limit of the system conducted interference transfer gain , calculate the upper limit of the conducted interference voltage transfer gain according to the above formula to ensure that the conducted interference of the system is lower than the limit specified by the EMC standard.

[0022] Preferably, the initial parameters of the components of the high-frequency filter for the silicon carbide controller are calculated according to the upper limit of the conducted interference voltage transfer gain, 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 Lmin(f) and the minimum number of inductors Lmin(i) are calculated from the upper limit of the conducted interference voltage transfer gain at each frequency.

[0023] Preferably, the initial parameters of the components of the high-frequency filter for the silicon carbide controller are calculated according to the upper limit of the conducted interference voltage transfer gain, and specifically: Define the filter volume as: ,where i represents the number of magnetic rings, i ≥ Lmin(i), 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; Assuming the width of the copper bar is B and the thickness is A, calculate the thickness c of 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 a distance E between the first copper bar and the second copper bar; Define the relationship between the volume of the magnetic ring and the inductance. The inductance value of the magnetic ring is expressed as: , where L is the inductance of the magnetic ring coil, F is the cross-section of the magnetic ring, and l is the average length of the magnetic circuit of the magnetic ring. is the relative magnetic permeability of the magnetic ring, which is a function of the frequency f. ; The formula and Substituting into the inductance expression of the magnetic ring, we get , , where D is the height of the runway magnetic ring, H is the thickness of the runway magnetic ring, R is the inner diameter of the runway magnetic ring surface, R1 is the outer diameter of the runway magnetic ring surface, and G is the straight length of the runway magnetic ring; According to the formula Calculate the volume of a single magnetic ring.

[0024] Preferably, the size requirements of the first copper bar and the second copper bar are: .

[0025] In this embodiment, the minimum number of magnetic rings, X capacitors, and Y capacitors required and the size of the magnetic ring are calculated according to the upper limit of the conducted interference voltage transfer gain. Specifically: First, the filter volume is defined: , i, j, k are the number of magnetic rings, X capacitors, and Y capacitors, , , They represent the volumes of the magnetic ring, X capacitor, and Y capacitor respectively.

[0026] See also Fig.11 , Secondly, design the copper busbar: According to the current level, the minimum cross-sectional area S of the copper busbar is determined by the electrical manual; Assuming that the width of the copper busbar is B and the thickness is A, the thickness c of the epoxy resin sprayed on the copper busbar surface is determined according to the following formula, , U is the operating voltage of the filter (V); determine the distance E between the two copper bars; the size of the copper bar meets the requirements: .

[0027] Finally, the relationship between the volume of the magnetic ring and the inductance is defined. The inductance value of the magnetic ring can be expressed as: , L is the inductance of the magnetic ring coil (H), F is the cross-sectional area of ​​the magnetic ring (cm2), L is the average length of the magnetic ring (cm), and μ is the relative magnetic permeability of the magnetic ring, which is a function of the frequency f.

[0028] Will , Substitution ,get: ;so, .

[0029] In summary, the volume of the magnetic ring can be calculated using the formula: .

[0030] Preferably, a genetic algorithm GA is used to optimize the component parameters of the high-frequency filter for the silicon carbide controller, specifically: For the cascade network composed of the mth and (m+1)th elements in the filter circuit of the high-frequency filter, the calculation formula of its transmission matrix is: , where the filter cascade matrix is ​​defined as: , N1, N2, N3, N4 are specific parameters in the transmission matrix; The mathematical expression of matrix M is defined as: , where det(N) is the value of the determinant of matrix N; The constraints on each element in the matrix M are: , using this as a preset constraint to iteratively optimize the filter topology; Use genetic algorithm to iteratively evolve the topology of magnetic ring, X capacitor and Y capacitor; When it is determined 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, the component is removed from the filter; When it is determined that the transmission parameter of the two elements connected in parallel or in series is less than a preset value for the transmission parameter matrix of the entire filter, the two elements are connected in parallel or in series; Under the preset constraints, according to the formula Compare the volumes before and after the calculation components are removed and connected in series; like , then continue topology optimization according to the results of the latest iteration; like , and the next calculation is performed based on the result of the previous iteration.

[0031] In this embodiment, a GA algorithm is used to optimize the filter topology, order, and element values.

[0032] The transmission parameter matrix of the EMI filter is the key, which determines the performance of the filter circuit and the impact on the contact current and leakage current. This matrix is ​​obtained by multiplying the transmission matrix of each unit in the filter circuit. For the cascade network composed of the mth and (m+1)th elements in the filter circuit, its transmission matrix is ​​calculated as follows: .

[0033] After defining the number of magnetic rings and the volume of each magnetic ring, the number of X capacitors and Y capacitors that meet the requirements, use genetic algorithms to iteratively evolve the topological structure of magnetic rings, X capacitors, and Y capacitors. If the transmission parameter matrix of an element has little effect on the transmission parameter matrix of the entire filter, then the contribution of this element to suppressing interference is very small and can be removed from the filter; if the transmission parameters of two elements connected in parallel or in series have little effect on the transmission parameter matrix of the entire filter, then the two elements can be considered to be connected in parallel or in series. Under the condition of satisfying the existing constraints, according to By comparing the volumes before and after the computing elements are removed and connected in series, the volume of the filter can be further reduced, thus achieving miniaturization of the filter.

[0034] Define the matrix M as: , let each element in M ​​satisfy the following constraints: .

[0035] Preferably, the insertion loss constraint is calculated based on the optimized component parameters, specifically: The insertion loss of the filter is constrained, and the insertion loss of the filter is estimated using the T parameter. The T parameter matrix of the series inductor and parallel capacitor is: , where ZLi is the inductive impedance and ZCj is the capacitive impedance; Calculate the impedance of the magnetic ring using the formula: ; Calculate the impedance of the capacitor using the formula: , where L C is the equivalent parasitic inductance of the capacitor, R C is the equivalent parasitic capacitance of the capacitor; The T parameter matrix of the filter is obtained as: , where T Li is the T parameter matrix corresponding to the inductance in the circuit, T Ci is the T parameter matrix corresponding to the capacitor; The insertion loss of the filter is calculated as: , where Z S is the system source impedance, Z L is the system load impedance; Using the formula Calculate the target insertion loss of the filter to verify whether it meets the requirements, where: is the target insertion loss of the filter, is the conduction interference voltage amplitude of the silicon carbide controller, is the limit value required by the standard, ; Insertion loss Split into CM insertion loss and DM insertion loss , and each constraint is expressed by the formula and Combined into a nonlinear constraint , judging whether the preset constraint conditions are met, wherein 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, , get the optimal filter solution; If not, continue to use the genetic algorithm GA to optimize the filter parameter components.

[0036] In this embodiment, the insertion loss constraint calculation is performed, and after the above conditions are met, the filter insertion loss constraint is: Use T parameters to estimate the insertion loss of the filter: The T parameter matrix of series inductance and shunt capacitance is as follows: , Z Li and Z Cj are the inductive and capacitive impedances respectively. The impedance of the magnetic ring can be calculated by the following formula: ; The impedance of the capacitor can be calculated as follows: , L C and R C are the equivalent parasitic inductance and equivalent parasitic capacitance of the capacitor respectively.

[0037] The T parameter matrix of the filter is: , then the insertion loss of the filter is calculated as: Z S is the system source impedance, Z L is the system load impedance.

[0038] Adoption To calculate the target insertion loss of the filter and verify whether it meets the requirements. : Target insertion loss of the filter; : The conduction interference voltage amplitude of the silicon carbide controller; : The limit value required by the standard. The requirements are: .

[0039] Insertion Constraint Loss Calculation: When implementing the filter optimization design algorithm, the insertion loss Split into CM insertion loss and DM insertion loss , each constraint is expressed by Japanese style Combined into a nonlinear constraint Φ. When the constraint condition is not met, Φ>0, when the constraint condition is met, Φ = 0; where b1 and b2 are the criteria for whether the CM insertion loss and DM insertion loss meet the constraint condition. 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.

[0040] Finally, an integrated filter is designed according to the optimal filtering scheme of the output, and the optimal filtering topology scheme is determined according to the filter design method of the silicon carbide controller, and the selected magnetic core, X capacitor, and Y capacitor are confirmed, and the filter structure is designed to further realize the miniaturization of the filter.

[0041] 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, which are used to assemble the runway-shaped magnetic core, and are sealed by glue filling after assembly to ensure that the magnetic core is firmly installed, while improving its vibration resistance and environmental tolerance, and enhancing the reliability of long-term use. 2. Two copper bars run through the two magnetic cores, respectively connecting the positive and negative poles to achieve efficient current conduction. The design of the copper bar ensures that the filter has excellent conductivity when handling high currents, while reducing energy loss and improving the overall working efficiency of the system. 3. A protruding isolation plastic sheet is set between the large and small magnetic rings to effectively separate the positive and negative poles and reduce the magnetic field coupling between the two. 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 connected to the copper bars of the positive and negative poles, respectively, which optimizes the installation position of the capacitor, simplifies the assembly process, and improves the stability of the electrical connection. 5. Grounding holes are opened on the outside of the two copper bars. One end of the Y capacitor is connected to the copper bar on the corresponding side, and the other end is grounded through the grounding hole. This grounding design not only effectively reduces the leakage current, but also further improves the electromagnetic compatibility performance of the filter and ensures the safety of system operation. 6. Screw holes are opened at the four corners of the filter to fix the filter body. This design ensures that the filter can be firmly installed in various application environments, effectively resists vibration and mechanical stress, and extends the service life of the equipment.

[0042] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A high-frequency filter for a silicon carbide controller, characterized in that: include: 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 to be connected to the positive pole of the external power line, the second copper bar passes through the ring bodies of the large magnetic ring and the small magnetic ring to be connected to the negative pole of the external power line, a spacing space is provided between the large magnetic ring and the small magnetic ring, the isolation plastic sheet is arranged in the spacing space, the X capacitor is arranged on the isolation plastic sheet, and the Y capacitor is arranged on the small magnetic ring; 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 electrode lines.

2. A high-frequency filter for a silicon carbide controller according to claim 1, characterized in that: The large magnetic ring and the small magnetic ring are both made of high magnetic performance materials.

3. A design method for a high-frequency filter for a silicon carbide controller, characterized in that: include: Calculate the interference frequency range and the upper limit of the conducted interference voltage transfer gain of the high-frequency filter for the silicon carbide controller as described in any one of claims 1 to 2; Calculating initial parameters of components of the high-frequency filter for the silicon carbide controller according to the upper limit of the conducted interference voltage transfer gain; Using a genetic algorithm GA to optimize component parameters of the high-frequency filter for the silicon carbide controller; The insertion loss constraint is calculated based on the optimized component parameters, the optimal filtering scheme is determined, and a high-frequency filter for the silicon carbide controller is designed.

4. The method for designing a high-frequency filter for a silicon carbide controller according to claim 3, characterized in that: The interference frequency range and the upper limit of the conducted interference voltage transfer gain of the high-frequency filter used in the silicon carbide controller are calculated as follows: According to the formula: Calculate the upper limit of the conducted interference voltage transfer gain, where Tranemi is the upper limit of the conducted interference voltage transfer gain, Stabilize network voltage for line impedance, is the conducted interference equivalent voltage.

5. The method for designing a high-frequency filter for a silicon carbide controller according to claim 4, characterized in that: The initial parameters of the components of the high-frequency filter for the silicon carbide controller are calculated according to the upper limit of the conducted interference voltage transfer gain, 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 Lmin(f) and the minimum inductance number Lmin(i) are calculated from the upper limit of the interference voltage transfer gain at each frequency.

6. The method for designing a high-frequency filter for a silicon carbide controller according to claim 5, characterized in that: The initial parameters of the components of the high-frequency filter for the silicon carbide controller are calculated according to the upper limit of the conducted interference voltage transfer gain, which is specifically: Define the filter volume as: , where i represents the number of magnetic rings, i ≥ Lmin(i), 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; Assuming the width of the copper bar is B and the thickness is A, calculate the thickness c of 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 a distance E between the first copper bar and the second copper bar; Define the relationship between the volume of the magnetic ring and the inductance. The inductance value of the magnetic ring is expressed as: , where L is the inductance of the magnetic ring coil, F is the cross-section of the magnetic ring, and l is the average length of the magnetic circuit of the magnetic ring. is the relative magnetic permeability of the magnetic ring, which is a function of the frequency f. ; The formula and Substituting into the inductance expression of the magnetic ring, we get , , where D is the height of the runway magnetic ring, H is the thickness of the runway magnetic ring, R is the inner diameter of the runway magnetic ring surface, R1 is the outer diameter of the runway magnetic ring surface, and G is the straight length of the runway magnetic ring; According to the formula Calculate the volume of a single magnetic ring.

7. The method for designing a high-frequency filter for a silicon carbide controller according to claim 6, characterized in that: The size requirements of the first copper bar and the second copper bar are: .

8. The method for designing a high-frequency filter for a silicon carbide controller according to claim 6, characterized in that: The component parameters of the high-frequency filter for the silicon carbide controller are optimized using a genetic algorithm GA, specifically: For the cascade network composed of the mth and (m+1)th elements in the filter circuit of the high-frequency filter, the calculation formula of its transmission matrix is: , where the filter cascade matrix is ​​defined as: , N1, N2, N3, N4 are specific parameters in the transmission matrix; The mathematical expression of matrix M is defined as: , where det(N) is the value of the determinant of matrix N; The constraints on each element in the matrix M are: , using this as a preset constraint to iteratively optimize the filter topology; Use genetic algorithm to iteratively evolve the topology of magnetic ring, X capacitor and Y capacitor; When it is determined 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, the component is removed from the filter; When it is determined that the transmission parameters of the two elements connected in parallel or in series have an influence on the transmission parameter matrix of the entire filter that is less than a preset value, the two elements are connected in parallel or in series; Under the preset constraints, according to the formula Compare the volumes before and after the calculation components are removed and connected in series; like , then continue topology optimization according to the results of the latest iteration; like , and the next calculation is performed based on the result of the previous iteration.

9. The method for designing a high-frequency filter for a silicon carbide controller according to claim 6, characterized in that: The insertion loss constraints are calculated based on the optimized component parameters, specifically: The insertion loss of the filter is constrained, and the insertion loss of the filter is estimated using the T parameter. The T parameter matrix of the series inductor and parallel capacitor is: , where ZLi is the inductive impedance and ZCj is the capacitive impedance; Calculate the impedance of the magnetic ring using the formula: ; Calculate the impedance of the capacitor using the formula: , where L C is the equivalent parasitic inductance of the capacitor, R C is the equivalent parasitic capacitance of the capacitor; The T parameter matrix of the filter is obtained as: , where T li is the T parameter matrix corresponding to the inductance in the circuit, T ci is the T parameter matrix corresponding to the capacitor; The insertion loss of the filter is calculated as: , where Z S is the system source impedance, Z L is the system load impedance; Using the formula Calculate the target insertion loss of the filter to verify whether it meets the requirements, where: is the target insertion loss of the filter, is the conduction interference voltage amplitude of the silicon carbide controller, is the limit value required by the standard, ; Insertion loss Split into CM insertion loss and DM insertion loss , and each constraint is expressed by the formula and Combined into a nonlinear constraint , judging whether the preset constraint conditions are met, wherein 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, , get the optimal filter solution; If not, continue to use the genetic algorithm GA to optimize the filter parameter components.

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