A bidirectional vehicle-mounted charger leakage detection device and a production process thereof

Abstract

The application relates to the technical field of electronic components, in particular to a bidirectional vehicle-mounted charger leakage detection device which comprises a bottom plate, a magnetic ring, a leakage current detection winding, a protective shell and a common-mode inductance winding, the magnetic ring is located above the bottom plate, the leakage current detection winding is wound outside the magnetic ring, the protective shell is arranged outside the leakage current detection winding, the pin of the leakage current detection winding penetrates through the protective shell, the common-mode inductance winding is provided with at least two groups, the plurality of groups of common-mode inductance windings are all wound outside the protective shell, the pin of the common-mode inductance penetrates through the bottom plate and is fixed with the bottom plate, the protective shell is used for separating the leakage current detection winding and the common-mode inductance winding, and the working magnetic flux density value of the magnetic ring is smaller than the saturation magnetic density value of the magnetic material selected by the magnetic ring; the application has the advantages of reducing the volume and cost during leakage current detection of the vehicle-mounted charger.

Description

Technical Field

[0001] This application relates to the field of electronic component technology, and in particular to a leakage current detection device for a bidirectional on-board charger and its manufacturing process. Background Technology

[0002] On-board chargers are widely used in high-voltage power battery charging systems for pure electric and hybrid new energy vehicles. Their main function is to rectify, isolate, and convert the AC mains input (single-phase voltage 220VAC, three-phase line voltage 380VAC) into the voltage and current required for battery charging. Bidirectional on-board chargers can not only charge the power battery in the forward direction, but also, when AC power is needed, adjust and invert the battery's electrical energy, transmitting it in the reverse direction to the AC charging port to power the connected equipment.

[0003] In related technologies, because AC loads differ from AC charging piles during reverse discharge, there are no corresponding protection measures. If the electrical equipment experiences leakage current abnormalities, there will be safety risks. To address the risk of leakage current and other abnormalities in electrical equipment, it is usually necessary to detect the leakage current at the AC input terminal of the charger. The conventional detection method uses a current transformer (CT). The input line at the input terminal is connected in common mode and passes through the magnetic ring of the CT. If no leakage current occurs, the currents in the input live wire and neutral wire are equal and cancel each other out, so the induced magnetic flux in the CT magnetic ring is 0, and no leakage current is detected at the secondary output of the CT. Conversely, if leakage current occurs, the currents between the input neutral wire and live wire are not completely equal, and the secondary side of the CT will sense the leakage current, triggering the charger's internal protection circuit, shutting off the reverse output, and providing protection.

[0004] However, while conventional solutions can safely detect abnormal leakage current during reverse output, they also require an additional current transformer (CT). This CT is quite large, especially in high-power applications, which increases the overall system size and cost. Summary of the Invention

[0005] To reduce the size and cost of detecting leakage current in on-board chargers, this application provides a bidirectional on-board charger leakage detection device and its manufacturing process.

[0006] The technical solution adopted in this application for a bidirectional on-board charger leakage detection device and its manufacturing process is as follows:

[0007] on the one hand:

[0008] A bidirectional on-board charger leakage current detection device includes a base plate, a magnetic ring, a leakage current detection winding, a protective shell, and a common-mode inductor winding. The magnetic ring is located above the base plate. The leakage current detection winding is wound around the outside of the magnetic ring. The protective shell is disposed outside the leakage current detection winding. The leads of the leakage current detection winding pass through the protective shell. At least two sets of common-mode inductor windings are provided, and multiple sets of common-mode inductor windings are wound around the outside of the protective shell. The leads of the common-mode inductor pass through the base plate and are fixed to the base plate. The protective shell is used to separate the leakage current detection winding and the common-mode inductor winding. The operating magnetic flux density of the magnetic ring is less than the saturation magnetic flux density of the magnetic material selected for the magnetic ring.

[0009] By adopting the above technical solution, the protective shell is used to separate the leakage current detection winding and the common mode inductor winding, reducing the impact of direct contact between the leakage current detection winding and the common mode inductor winding on the detection of leakage current. The common mode inductor winding and the magnetic ring are combined to form an EMC common mode inductor. In addition, since the working magnetic flux density of the magnetic ring is less than the saturation magnetic flux density of the magnetic material selected for the magnetic ring, the occurrence of magnetic flux saturation of the magnetic ring is reduced. Therefore, the EMC common mode inductor parameters are preserved as much as possible. In this application, the leakage current detection winding and the common mode inductor winding share a single magnetic ring, reducing the necessity of adding a CT and reducing the volume and cost of leakage current detection for the on-board charger.

[0010] Preferably, the protective shell includes a bottom shell and a cover. The bottom shell is open and covers the outside of the magnetic ring. The cover covers the opening of the bottom shell and is fixedly connected to the bottom shell.

[0011] By adopting the above technical solution, a magnetic ring with a leakage current detection winding is placed inside the bottom shell, and then the shell cover is closed on the opening of the bottom shell and the shell cover and the bottom shell are fixed. Finally, the common mode inductor winding is wound on the outside of the protective shell, thereby realizing the separation between the leakage current detection winding and the common mode inductor winding, reducing the mutual interference between the leakage current detection winding and the common mode inductor winding, and making the leakage current detection device have a certain degree of working stability.

[0012] Preferably, the inner wall of the bottom shell is provided with a positioning groove, the surface of the shell cover abuts against the bottom of the positioning groove, and a glue-filled gap is formed between the side wall of the shell cover and the groove wall of the positioning groove.

[0013] By adopting the above technical solution, when the cover is closed at the opening of the bottom shell, the surface of the cover abuts against the bottom of the positioning groove. The positioning groove can play a positioning role in the installation of the cover. Then, glue is filled into the glue filling gap to facilitate the glue fixation between the cover and the bottom shell.

[0014] Preferably, the outer side wall of the shell cover has an inclined surface, which is oriented toward the groove wall of the positioning groove.

[0015] By adopting the above technical solution, the outer side wall of the cover is opened with a slope facing the groove wall of the positioning groove, so as to increase the contact area between the cover and the glue and improve the connection between the cover and the bottom shell.

[0016] Preferably, the base plate has multiple pin holes, some of which are into which pins are inserted. The pins of the leakage current detection winding are wound around the outer wall of the pins, and the pins of the common mode inductor winding are connected to the remaining pin holes one by one.

[0017] By adopting the above technical solution, pinholes are opened on the base plate to facilitate the installation and positioning of the pins of the common mode inductor winding. Since the number of turns of the leakage current detection winding is usually high, the pin structure strength of the leakage current detection winding is generally low. The pins of the leakage current detection winding are wound around the outer wall of the pin so that they can make contact with other components through the pin with higher structural strength to transmit signals.

[0018] Preferably, the number of common mode inductor windings is set to two or more, and the multiple sets of common mode inductor windings are arranged equidistantly in a circle.

[0019] By adopting the above technical solution, the number of common mode inductor windings is set to two or more, which enables the detection device to be adapted to domestic and foreign power grids, such as single-phase, three-phase four-wire or three-phase three-wire input configurations, thereby improving the applicability of the detection device.

[0020] on the other hand:

[0021] A manufacturing process for a bidirectional on-board charger leakage current detection device, used to produce the bidirectional on-board charger leakage current detection device as described above, includes the following steps:

[0022] S1: The leakage current detection winding is wound on the outside of the magnetic ring;

[0023] S2: Place the magnetic ring inside the bottom shell and pass the leads of the leakage current detection winding through the bottom shell. Apply adhesive between the leads of the leakage current detection winding and the bottom shell.

[0024] S3: Apply adhesive to the wall of the positioning groove, then put the cover on the positioning groove and fill the gaps with adhesive.

[0025] S4: Multiple common-mode inductor windings are wound at equal intervals on the outside of the bottom shell;

[0026] S5: Pass the pins of the common mode inductor winding through some of the pin holes on the base plate, and insert the pins into the remaining pin holes. Solder and fix the pins and the pins of the common mode inductor winding to the surface of the base plate.

[0027] S6: Wind the lead of the leakage current detection winding onto the pin, and apply adhesive to fix the pin, common mode inductor winding, common mode inductor winding lead and protective shell to the surface of the base plate.

[0028] By adopting the above technical solution, the leakage current detection winding is wound around the outside of the magnetic ring to form a detection device for detecting the leakage current of a bidirectional on-board charger. At the same time, the magnetic ring is placed inside the bottom shell, and the pins of the leakage current detection winding are passed through the bottom shell. Adhesive is applied between the pins of the leakage current detection winding and the bottom shell to isolate and protect the magnetic ring on which the leakage current detection winding is wound. In addition, by applying adhesive into the positioning groove and the filling gap, the adhesive fixing between the cover and the bottom shell is facilitated.

[0029] Preferably, the welding method used in step S5 is wave soldering.

[0030] By adopting the above technical solutions, the reliability of welding can be improved.

[0031] Preferably, lead-free hot solder is used as the soldering material in step S5.

[0032] By adopting the above technical solution, the amount of waste residue generated after lead-free hot soldering is less than that of ordinary solder, and it has very good anti-oxidation properties.

[0033] Preferably, the thickness of the solder paste used in step S5 is set to 0.15 mm.

[0034] By adopting the above technical solution, the base plate can be fully welded to the pins and the common mode inductor winding.

[0035] In summary, this application includes at least one of the following beneficial technical effects:

[0036] 1. To preserve EMC common mode inductor parameters as much as possible, the leakage current detection winding and common mode inductor winding in this application share a magnetic ring, reducing the need to add a CT and reducing the size and cost of leakage current detection for on-board chargers;

[0037] 2. Place the magnetic ring with the leakage current detection winding inside the bottom shell, then close the shell cover to the opening of the bottom shell and fix the shell cover and the bottom shell. Finally, wind the common mode inductor winding on the outside of the protective shell, thereby realizing the separation between the leakage current detection winding and the common mode inductor winding, reducing the mutual interference between the leakage current detection winding and the common mode inductor winding, so that the leakage current detection device has a certain working stability.

[0038] 3. The outer side wall of the cover is provided with a slope facing the groove wall of the positioning groove to increase the contact area between the cover and the glue, improve the connection between the cover and the bottom shell, and make the leakage detection device have a certain degree of operational stability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the bidirectional on-board charger leakage detection device in the embodiments of this application.

[0040] Figure 2 This is an exploded view of the bidirectional on-board charger leakage detection device in the embodiments of this application.

[0041] Explanation of reference numerals in the attached diagram: 1. Base plate; 11. Pinhole; 12. Pin; 2. Magnetic ring; 3. Leakage current detection winding; 4. Common mode inductor winding; 5. Protective shell; 51. Bottom shell; 511. Leaning opening; 52. Shell cover; 521. Sloping surface. Detailed Implementation

[0042] The following is in conjunction with the appendix Figure 1 and Figure 2 This application will be described in further detail.

[0043] This application discloses a leakage current detection device for a bidirectional on-board charger and its manufacturing process. (Refer to...) Figure 1 and Figure 2 A bidirectional on-board charger leakage current detection device includes a base plate 1, a magnetic ring 2, a leakage current detection winding 3, a common mode inductor winding 4, and a protective shell 5. The base plate 1 serves as the carrier for the magnetic ring 2, the leakage current detection winding 3, the common mode inductor winding 4, and the protective shell 5.

[0044] In addition, the magnetic ring 2 and the leakage current detection winding 3 are combined to form a leakage current detection device for detecting the leakage current of the bidirectional on-board charger. At the same time, the magnetic ring 2 and the common mode inductor winding 4 are combined to form a common mode inductor filter device. In this embodiment, the working principle of the leakage current detection device and the common mode inductor filter device can be referred to the current transformer in conventional technology.

[0045] The detection device in this application is used in a three-phase four-wire mains input. Furthermore, the protective housing 5 separates the leakage current detection winding 3 from the common-mode inductor winding 4, enabling the detection device to perform common-mode filtering and leakage current detection normally.

[0046] Specifically, the magnetic ring 2 is located above the base plate 1. The magnetic ring 2 is circular and made of nanocrystalline material. The specific model of the magnetic ring 2 is T42*32*12. At the same time, the leakage current detection winding 3 is wound on the outer wall of the magnetic ring 2. The number of turns of the leakage current detection winding 3 is 800±8TS. The winding method of the leakage current detection winding 3 is 360 degrees uniform and dense winding. The wire used for the leakage current detection winding 3 is ￠2.0mm.

[0047] Correspondingly, the protective shell 5 is also arranged in a ring shape. The protective shell 5 includes a bottom shell 51 and a cover 52. The bottom shell 51 is open and covers the outside of the magnetic ring 2. The cover 52 covers the opening of the bottom shell 51 and is fixedly connected to the bottom shell 51.

[0048] Furthermore, the inner wall of the bottom shell 51 is provided with a positioning groove (not shown in the figure). The positioning groove is an annular groove that penetrates the surface of the bottom shell 51. The surface of the cover 52 abuts against the bottom of the positioning groove, and a glue-filled gap is formed between the side wall of the cover 52 and the groove wall of the positioning groove. At the same time, the outer side wall of the cover 52 is provided with a bevel 521, which is arranged circumferentially around the cover 52 and faces the groove wall of the positioning groove.

[0049] Specifically, when the cover 52 is placed over the opening of the bottom shell 51, the surface of the cover 52 abuts against the bottom of the positioning groove. The positioning groove positions the cover 52 during installation. Adhesive is then filled into the gaps to facilitate adhesive fixation between the cover 52 and the bottom shell 51. Furthermore, the outer wall of the cover 52 has a bevel 521 facing the groove wall of the positioning groove to increase the contact area between the cover 52 and the adhesive, thereby improving the connection strength between the cover 52 and the bottom shell 51.

[0050] Furthermore, the number of common-mode inductor windings 4 is set to two or more, which allows the detection device to be adapted to domestic and international power grids, such as single-phase, three-phase four-wire, or three-phase three-wire input configurations, thus improving the applicability of the detection device. Similarly, the wire used for the common-mode inductor windings 4 is also ￠2.0mm. In this embodiment, four common-mode inductor windings 4 are set, and the common-mode inductor windings 4 are wound on the surface of the protective shell 5. The number of turns of the common-mode inductor windings 4 is 4Ts. The common-mode inductor windings 4 and the magnetic ring 2 are combined to form a common-mode inductor device.

[0051] It should be noted that, in order to ensure the normal operation of the common-mode inductor device (i.e., EMC common-mode inductor) formed by the combination of the common-mode inductor winding 4 and the magnetic ring 2, the operating magnetic flux density of the magnetic ring 2 needs to be less than the saturation magnetic flux density of the magnetic material selected for the magnetic ring 2. In this embodiment, the number of turns of the leakage current detection winding 3 can be adjusted to adjust the operating magnetic flux density of the magnetic ring 2. The minimum number of turns of the leakage current detection winding 3 can be obtained by the following formula:

[0052] N_min=(Lm*I_leakage) / (B_max*Ae);

[0053] Where N_min is the minimum number of turns of the N1 winding, Lm is the inductance of the N1 winding, I_leakage is the leakage current induced by N1, B_max is the saturation magnetic flux density of the common-mode inductor core, and Ae is the effective cross-sectional area of ​​the common-mode inductor core.

[0054] In addition, the base plate 1 has multiple pin holes 11, and pins 12 are inserted into several of the pin holes 11. The outer wall of the bottom shell 51 has a clearance opening 511. The pins of the leakage current detection winding 3 pass through the clearance opening 511 and are wound around the outer wall of the pins 12. The pins of the common mode inductor winding 4 are connected to the remaining pin holes 11 one by one.

[0055] Specifically, pinholes 11 are provided on the base plate 1 to facilitate the installation and positioning of the pins of the common mode inductor winding 4. Since the number of turns of the leakage current detection winding 3 is usually high, the pin structure strength of the leakage current detection winding 3 is generally low. The pins of the leakage current detection winding 3 are wound around the outer wall of the pin 12 so that they can make contact with other components through the pin 12 with higher structural strength to transmit signals.

[0056] The implementation principle of the bidirectional on-board charger leakage current detection device in this application embodiment is as follows: The protective shell 5 is used to separate the leakage current detection winding 3 and the common mode inductor winding 4, reducing the impact of direct contact between the leakage current detection winding 3 and the common mode inductor winding 4 on the detection of leakage current. The common mode inductor winding 4 and the magnetic ring 2 are combined to form an EMC common mode inductor. In addition, since the working magnetic flux density value of the magnetic ring 2 is less than the saturation magnetic flux density value of the magnetic material selected for the magnetic ring 2, the occurrence of magnetic flux saturation of the magnetic ring 2 is reduced. Therefore, the EMC common mode inductor parameters are preserved as much as possible. In this application, the leakage current detection winding 3 and the common mode inductor winding 4 share a magnetic ring 2, reducing the necessity of adding a CT and reducing the volume and cost of leakage current detection of the on-board charger.

[0057] In addition, this application also discloses a manufacturing process for a bidirectional on-board charger leakage current detection device, specifically including:

[0058] S1: The leakage current detection winding 3 is wound around the outside of the magnetic ring 2;

[0059] S2: Place the magnetic ring 2 inside the bottom shell 51, and pass the pin of the leakage current detection winding 3 out of the bottom shell 51. Apply glue between the pin of the leakage current detection winding 3 and the bottom shell 51.

[0060] S3: Apply adhesive to the wall of the positioning groove, then put the cover 52 on the positioning groove and fill the gaps with adhesive.

[0061] S4: Multiple common-mode inductor windings 4 are wound at equal intervals on the outside of the bottom shell 51;

[0062] S5: Pass the pins of the common mode inductor winding 4 through some of the pin holes 11 on the base plate 1, and insert the pins 12 into the remaining pin holes 11. Solder and fix the pins 12 and the pins of the common mode inductor winding 4 to the surface of the base plate 1.

[0063] S6: The pins of the leakage current detection winding 3 are wound onto pin 12, and pin 12, common mode inductor winding 4, the pins of common mode inductor winding 4 and protective shell 5 are fixed to the surface of base plate 1 with glue.

[0064] Specifically, the leakage current detection winding 3 is wound around the outside of the magnetic ring 2 to form a detection device for detecting the leakage current of the bidirectional on-board charger. At the same time, the magnetic ring 2 is placed inside the bottom shell 51, and the pins of the leakage current detection winding 3 are passed through the bottom shell 51. Adhesive is applied between the pins of the leakage current detection winding 3 and the bottom shell 51 to isolate and protect the magnetic ring 2 on which the leakage current detection winding 3 is wound. In addition, by applying adhesive to the positioning groove and the filling gap, the adhesive fixing between the cover 52 and the bottom shell 51 is facilitated.

[0065] Furthermore, the soldering method used in step S5 is wave soldering to improve the reliability of the soldering. In step S5, lead-free hot solder is used as the soldering material. Lead-free hot solder produces less slag after melting than ordinary solder, and it has excellent oxidation resistance. The thickness of the solder paste used is set to 0.15mm to ensure that the base plate 1 can be completely soldered to the pins 12 and the common-mode inductor winding 4.

[0066] In addition, the operating conditions of the bidirectional on-board charger leakage detection device in this application are as follows: normal ambient temperature: -40~+125℃; ambient humidity: 5%~95%; storage ambient temperature: -40~+100℃.

[0067] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bidirectional on-board charger leakage detection device, characterized in that: It comprises a bottom plate (1), a magnetic ring (2), a leakage current detection winding (3), a protective shell (5) and a common mode inductance winding (4), the magnetic ring (2) is above the bottom plate (1), the leakage current detection winding (3) is wound outside the magnetic ring (2), the protective shell (5) is arranged outside the leakage current detection winding (3), the pin of the leakage current detection winding (3) penetrates the protective shell (5), the common mode inductance winding (4) is provided with at least two groups, and the plurality of common mode inductance windings (4) are wound outside the protective shell (5), the pin of the common mode inductance penetrates the bottom plate (1) and is fixed with the bottom plate (1), the protective shell (5) is used for separating the leakage current detection winding (3) and the common mode inductance winding (4), the working magnetic flux density value of the magnetic ring (2) is less than the saturation magnetic density value of the selected magnetic material of the magnetic ring (2); The material of the magnetic ring (2) is nanocrystalline, and the working magnetic flux density value of the magnetic ring (2) can be adjusted by adjusting the number of turns of the leakage current detection winding (3), and the minimum number of turns of the leakage current detection winding (3) is obtained by the following formula: N_min=(Lm*I_leakage) / (B_max*Ae); Wherein, N_min is the minimum number of turns of N1 winding, Lm is the inductance of N1 winding, I_leakage is the leakage current value induced by N1, B_max is the saturation magnetic density of common mode inductance magnetic core, Ae is the effective cross-sectional area of common mode inductance magnetic core.

2. The leakage detection device of a bidirectional on-board charger according to claim 1, characterized in that: The protective shell (5) comprises a bottom shell (51) and a shell cover (52), the bottom shell (51) is provided with an opening, the bottom shell (51) covers the outside of the magnetic ring (2), and the shell cover (52) covers the opening of the bottom shell (51), and the shell cover (52) is fixedly connected with the bottom shell (51).

3. The leakage detection device of bidirectional on-board charger according to claim 2, characterized in that: The inner wall of the bottom shell (51) is provided with a positioning groove, the surface of the shell cover (52) is abutted with the groove bottom of the positioning groove, and the side wall of the shell cover (52) and the groove wall of the positioning groove form a glue filling gap.

4. The leakage detection device of bidirectional on-board charger according to claim 3, characterized in that: The outer side wall of the shell cover (52) is provided with an inclined surface (521), and the inclined surface (521) is arranged towards the groove wall of the positioning groove.

5. The leakage detection device of bidirectional on-board charger according to claim 1, characterized in that: The bottom plate (1) is provided with a plurality of pin holes (11), and a plurality of pin holes (11) are inserted with pin pins (12), the pin of the leakage current detection winding (3) is wound outside the outer wall of the pin (12), and the pin of the common mode inductance winding (4) is inserted and matched with the remaining pin holes (11) one by one.

6. The leakage detection device of bidirectional on-board charger according to claim 1, wherein: The number of the common mode inductance winding (4) is two or more, and the plurality of common mode inductance windings (4) are arranged at equal intervals in a circle.

7. A production process of a bidirectional on-board charger leakage detection device, for producing the bidirectional on-board charger leakage detection device according to any one of claims 1 to 6, characterized by, It comprises the following steps: S1: winding the leakage current detection winding (3) outside the magnetic ring (2); S2: placing the magnetic ring (2) inside the bottom shell (51), and making the pin of the leakage current detection winding (3) penetrate out of the bottom shell (51), and point gluing between the pin of the leakage current detection winding (3) and the bottom shell (51); S3: point gluing is carried out on the groove wall of the positioning groove, and the shell cover (52) is covered on the positioning groove, and the glue filling gap is filled with glue. S4: A plurality of common mode inductance winding (4) is equidistantly wound outside the bottom shell (51); S5: The pins of the common mode inductance winding (4) are passed through part of the pinholes (11) on the bottom plate (1), while the needle pins (12) are inserted into the remaining pinholes (11), and the needle pins (12) and the pins of the common mode inductance winding (4) are welded and fixed on the surface of the bottom plate (1); S6: The pins of the leakage current detection winding (3) are wound on the needle pins (12), and the needle pins (12), the common mode inductance winding (4), the pins of the common mode inductance winding (4) and the protective shell (5) are glued and fixed on the surface of the bottom plate (1).

8. The production process of a bidirectional vehicle charger leakage detection device according to claim 7, characterized in that: The welding method used in step S5 is wave soldering.

9. The production process of a bidirectional vehicle charger leakage detection device according to claim 8, wherein: The soldering material used in step S5 is lead-free soldering.

10. The production process of a bidirectional vehicle charger leakage detection device according to claim 9, wherein: The thickness of the solder paste used in step S5 is set to 0.15mm.

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