CN210970706U

CN210970706U - Electric automobile and vehicle-mounted charger thereof

Info

Publication number: CN210970706U
Application number: CN201921426984.4U
Authority: CN
Inventors: 张信; 石雷; 韩冰; 哈米德; 陈明文
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-08-28
Filing date: 2019-08-28
Publication date: 2020-07-10
Anticipated expiration: 2029-08-28

Abstract

The utility model discloses an electric automobile and on-vehicle machine that charges thereof, wherein, on-vehicle machine that charges includes: the alternating current end of the PFC circuit is connected with a power grid; the direct current end of the DC/AC conversion circuit is connected with the direct current end of the PFC circuit; the transformer comprises a primary coil, a first secondary coil and a second secondary coil, wherein the primary coil is connected with the alternating current end of the DC/AC conversion circuit; the alternating current end of the first AC/DC conversion circuit is connected with the first auxiliary coil, and the direct current end of the first AC/DC conversion circuit is connected with the power battery; and the alternating current end of the second AC/DC conversion circuit is connected with the second secondary side coil, and the direct current end of the second AC/DC change circuit is connected with the low-voltage storage battery. The vehicle-mounted charger reduces the use of parts, thereby reducing the cost of the parts, reducing the volume of the parts and lightening the weight of the parts.

Description

Electric automobile and vehicle-mounted charger thereof

Technical Field

The utility model relates to the technical field of automobiles, especially, relate to an electric automobile and on-vehicle machine that charges thereof.

Background

With the development of new energy vehicles, the requirements of the OBC (On-board charger) and the On-board DC (direct current) On cost, volume, weight and the like are higher and higher, and the discrete OBC and the On-board DC cannot meet the development requirements of the new energy vehicles. At present, two-in-one scheme products for integrating OBC and vehicle-mounted DC exist in the market, but most schemes only realize integration through simple electrical connection of a bus, and the integration level is low.

SUMMERY OF THE UTILITY MODEL

The present invention aims at solving at least one of the technical problems in the related art to a certain extent. Therefore, an object of the utility model is to provide an electric automobile's on-vehicle machine that charges to reduce the use of spare part, reduce the cost of the on-vehicle machine that charges, reduce the volume of the on-vehicle machine that charges, alleviate the weight of the on-vehicle machine that charges.

In order to achieve the above object, the utility model discloses the first aspect provides an electric automobile's on-vehicle machine that charges, electric automobile includes power battery and low voltage battery, the on-vehicle machine that charges includes: a PFC (Power factor correction) circuit, wherein an AC end of the PFC circuit is connected with a Power grid; the direct current end of the DC/AC conversion circuit is connected with the direct current end of the PFC circuit; the transformer comprises a primary coil, a first secondary coil and a second secondary coil, and the primary coil is connected with the alternating current end of the DC/AC conversion circuit; the alternating current end of the first AC/DC conversion circuit is connected with the first secondary coil, and the direct current end of the first AC/DC conversion circuit is connected with the power battery; and the alternating current end of the second AC/DC conversion circuit is connected with the second secondary side coil, and the direct current end of the second AC/DC conversion circuit is connected with the low-voltage storage battery.

The utility model discloses an on-vehicle machine that charges through a transformer and a DC AC converting circuit, can realize giving power battery and low voltage battery with the energy transmission of electric wire netting to and through foretell transformer and two AC converting circuit, can realize that power battery supplies power for the low voltage battery, from this, the use of spare part has been reduced, thereby the cost of on-vehicle machine that charges has been reduced, the volume of on-vehicle machine that charges has been reduced, the on-vehicle machine weight that charges has alleviateed.

In order to achieve the above object, the utility model discloses the second aspect provides an electric automobile, electric automobile includes foretell electric automobile's on-vehicle machine that charges.

The utility model discloses electric automobile adopts foretell on-vehicle machine that charges, through a transformer and a DC AC converting circuit, can realize giving power battery and low voltage battery with the energy transmission of electric wire netting to and through foretell transformer and two AC DC converting circuit, can realize that power battery supplies power for low voltage battery, from this, has reduced the use of spare part, makes on-vehicle machine that charges's cost reduction, volume reduction, weight reduction.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a block diagram of a vehicle-mounted charger of an electric vehicle according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a first example of the vehicle-mounted charger of the present invention;

fig. 3 is a schematic diagram of energy transmission in the vehicle-mounted charger according to the first example of the present invention;

fig. 4 is a schematic diagram of energy transmission in a vehicle-mounted charger according to a second example of the present invention;

fig. 5 is a schematic diagram of energy transmission in a third example of the vehicle-mounted charger of the present invention;

fig. 6 is a schematic diagram of energy transmission in a fourth example of the vehicle-mounted charger of the present invention;

fig. 7 is a schematic structural diagram of a vehicle-mounted charger according to a second example of the present invention;

fig. 8 is a schematic structural diagram of a third example of the vehicle-mounted charger of the present invention;

fig. 9 is a block diagram of an electric vehicle according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

The electric automobile and the vehicle-mounted charger thereof according to the embodiment of the present invention are described below with reference to the drawings.

Fig. 1 is a block diagram of a vehicle-mounted charger of an electric vehicle according to an embodiment of the present invention.

In this embodiment, the electric vehicle comprises a power battery P-battery and a low-voltage battery L-battery as shown in fig. 1, and the vehicle-mounted charger comprises a PFC circuit 10, a DC/AC conversion circuit 20, a transformer 30, a first AC/DC conversion circuit 40 and a second AC/DC conversion circuit 50.

Referring to fig. 1, an AC terminal of a PFC circuit 10 is connected to a power grid, a DC terminal of a DC/AC conversion circuit 20 is connected to a DC terminal of the PFC circuit 10, a transformer 30 includes a primary winding Np1, a first secondary winding Ns1 and a second secondary winding Ns2, the primary winding Np1 is connected to the AC terminal of the DC/AC conversion circuit 20, the AC terminal of the first AC/DC conversion circuit 40 is connected to the first secondary winding Ns1, the DC terminal of the first AC/DC conversion circuit 40 is connected to a power battery P-battery, the AC terminal of the second AC/DC conversion circuit 50 is connected to the second secondary winding Ns2, and the DC terminal of the second AC/DC conversion circuit 50 is connected to a low-voltage battery L-battery (e.g., a 12V battery).

Specifically, referring to fig. 1, the present invention relates to a vehicle-mounted charger, which employs transformer magnetic integration (i.e. one or more magnetic devices are structurally integrated together, e.g. share a magnetic core) technology, shares primary coil input of the transformer, and outputs two secondary coils, wherein one secondary coil (i.e. the first secondary coil Ns1) output is connected to the power battery P-battery through the first AC/DC conversion circuit 40 on the power battery P-battery side, and the other secondary coil (i.e. the second secondary coil Ns2) output is connected to the low-voltage battery L-battery through the second AC/DC conversion circuit 50 on the low-voltage battery L-battery side, and the OBC shares the DC/AC conversion circuit with the vehicle-mounted DC.

As an example, as shown in fig. 2, the PFC circuit 10 includes a first capacitor C1, a first inductor L, a first arm 11 and a second arm 12, one end of the first capacitor C1 is connected to a live wire of a power grid, the other end of the first capacitor C1 is connected to a neutral wire of the power grid, one end of the first inductor L is connected to one end of a first capacitor C1 and the live wire of the power grid, respectively, a midpoint of the first arm 11 is connected to the other end of the first inductor L, the first arm 11 includes a first switch Q1 and a second switch Q2 connected in series, a midpoint of the second arm 12 is connected to the other end of the first capacitor C1 and the neutral wire of the power grid, respectively, and the second arm 12 is connected in parallel to the first arm 11 to form a first current collection end and a second current collection end, the first current collection end is connected to a first port of a DC/AC conversion circuit 20, the second arm 12 is connected to a second current collection port of the DC/AC conversion circuit 20, the second arm 3 includes a second switch Q25 connected in series and a fourth switch Q25 connected in series.

Referring to fig. 2, the vehicle-mounted charger further includes: a second capacitor C2 and a second capacitor C2 are connected between the PFC circuit 10 and the DC/AC conversion circuit 20, one end of the second capacitor C2 is connected to the first bus terminal, and the other end of the second capacitor C2 is connected to the second bus terminal. The second capacitor C2 functions as a dc bus capacitor and filters the dc power output by the PFC circuit 10.

Referring to fig. 2, the DC/AC conversion circuit 20 includes: third leg 21 and fourth leg 22. The middle point of the third bridge arm 21 is connected with one end of the primary coil Np1, and the third bridge arm 21 comprises a fifth switching tube Q5 and a sixth switching tube Q6 which are connected in series; the midpoint of the fourth bridge arm 22 is connected to the other end of the primary coil Np1, the fourth bridge arm 22 is connected to the third bridge arm 21 in parallel to form a third junction end and a fourth junction end, the third junction end is connected to the first port of the dc end of the PFC circuit 10, the fourth junction end is connected to the second port of the dc end of the PFC circuit 10, and the fourth bridge arm 22 includes a seventh switching tube Q7 and an eighth switching tube Q8 connected in series to each other.

Referring to fig. 2, the first AC/DC conversion circuit 40 includes: fifth leg 41, sixth leg 42, and third capacitor C3. The middle point of the fifth bridge arm 41 is connected with one end of the first secondary coil Ns1, and the fifth bridge arm 42 comprises a ninth switching tube Q9 and a tenth switching tube Q10 which are connected in series; the middle point of the sixth bridge arm 42 is connected with the other end of the first minor edge coil Ns1, the sixth bridge arm 42 is connected with the fifth bridge arm 41 in parallel to form a fifth junction end and a sixth junction end, the fifth junction end is connected with the first pole of the power battery P-battery, the sixth junction end is connected with the second pole of the power battery P-battery and grounded, and the sixth bridge arm comprises an eleventh switching tube and a twelfth switching tube which are connected in series; one end of the third capacitor C3 is connected to the fifth bus terminal and the first pole of the power battery P-battery, and the other end of the third capacitor C3 is connected to the sixth bus terminal and the second pole of the power battery P-battery, and is grounded.

The first pole of the power battery P-battery can be a positive pole, and the second pole of the power battery P-battery is a negative pole.

Referring to fig. 2, the second AC/DC conversion circuit 50 includes a thirteenth switching tube Q13, a fourteenth switching tube Q14, a second inductor L, a third inductor L and a fourth capacitor C4, a drain of the thirteenth switching tube Q13 is connected to one end of a second sub-boundary coil Ns2, a source of the thirteenth switching tube Q13 is connected to a second pole of the low-voltage battery 13-battery and grounded, a source of the fourteenth switching tube Q13 is connected to the source of the thirteenth switching tube Q13 and the second pole of the low-voltage battery 13 1-battery respectively and grounded, a drain of the fourteenth switching tube Q13 is connected to the other end of the second sub-boundary coil Ns 13, one end of a second inductor 13 is connected to the drain of the thirteenth switching tube Q13 and one end of the second sub-boundary coil Ns 13 respectively, the other end of the second inductor 3632 is connected to the first pole of the low-voltage battery 364-battery 13 and the drain of the fourteenth switching tube Q72, and the drain of the second inductor Q13 are connected to the second sub-gate of the second sub-boundary coil Ns 13, the drain of the second inductor Q13 and the drain of the second sub-switch 13 are connected to the drain of the second sub-switch 13, the second terminal of the second inductor Q13 and the drain of the second sub-gate of the second sub-switch 13, the second sub-switch 13 are connected to the second terminal of the second sub-gate of the second inductor Q13, the second sub-gate of the second sub-switch 13, the second sub-gate of the second inductor 13.

The first pole of the low-voltage battery L-battery can be a positive pole, and the second pole of the low-voltage battery L-battery can be a negative pole.

The second AC/DC conversion circuit 50 employs a current doubling circuit, so that no center tap is provided on the secondary side of the transformer 30, thereby reducing the design difficulty of the transformer 30. meanwhile, two filter inductors (i.e. the second inductor L and the third inductor L) are provided in the current doubling circuit, which is beneficial to the heat dissipation design of the filter inductors, and improves the power efficiency.

Referring to fig. 2, the vehicle-mounted charger further includes a fourth inductor L4 and a fifth capacitor C5., wherein one end of the fourth inductor L4 is connected to the midpoint of the third leg 21, the other end of the fourth inductor L4 is connected to one end of the primary coil Np1, one end of the fifth capacitor C5 is connected to the midpoint of the fourth leg 22, and the other end of the fifth capacitor C5 is connected to the other end of the primary coil Np1, and the fourth inductor L4, the fifth capacitor C5 and the primary coil Np1 are connected in series to form a resonant circuit.

The working principle of the vehicle-mounted charger according to the embodiment of the present invention is described below with reference to fig. 3 to 6:

the vehicle-mounted charger works in a first mode, namely a power grid charges a low-voltage storage battery L-battery, before a power battery P-battery is charged, the power grid firstly charges the low-voltage storage battery L-battery when the SOC (State of Charge) value of the low-voltage storage battery L-battery is lower than a first set value, after the power battery P-battery is charged, the SOC value of the low-voltage storage battery L-battery is judged, when the SOC value of the low-voltage storage battery L-battery is lower than a second set value, the low-voltage storage battery L-battery is charged until the SOC value is 100%, and the charging of a whole vehicle is judged to be finished, in the first mode, referring to fig. 3, the energy on the side of the power grid charges the low-voltage storage battery through a PFC circuit 10, a DC/AC conversion circuit 20, a fourth inductor L4, a primary coil Np1, a fifth capacitor C5, a second secondary coil 2 of a transformer 30 and a second AC/DC conversion circuit Ns/DC conversion circuit 6350-battery L on the side of the low-battery L-battery.

The values of the first set value and the second set value can be the same or different.

After the SOC value of the low-voltage storage battery L-battery is judged to be larger than a third set value, referring to fig. 4, the energy on the grid side charges the power battery P-battery through a PFC circuit 10, a DC/AC conversion circuit 20, a fourth inductor L4, a primary coil Np1 of a transformer 30, a fifth capacitor C5, a first secondary coil Ns1 of the transformer 30 and a first AC/DC circuit 40 on the power battery P-battery side.

The third set value is larger than the first set value and the second set value.

Referring to fig. 5, the energy of the power battery P-battery sequentially passes through the first AC/DC circuit 40 at the power battery P-battery side, the first secondary coil Ns1 of the transformer 30, the primary coil Np1 of the transformer 30, the fourth inductor L4, the fifth capacitor C5, the DC/AC conversion circuit 20 and the PFC circuit 10 to discharge outside the vehicle, such as 220V/50 Hz.

The vehicle-mounted charger works in a fourth mode, wherein the power battery P-basic discharges to a low-voltage load and a low-voltage storage battery L-basic, and when the low-voltage load is started or the electric quantity of the low-voltage storage battery L-basic is lower than a fourth set value, the power battery P-basic needs to discharge to the low-voltage load and the low-voltage storage battery L-basic, in the fourth mode, referring to fig. 6, the energy of the power battery P-basic discharges to the low-voltage load and the low-voltage storage battery L-basic through a first AC/DC conversion circuit 40 at the side of the power battery P-basic, a first secondary coil Ns1 of a transformer 30, a second secondary coil Ns2 of the transformer 30 and a second AC/DC conversion circuit 50 at the side of a storage battery L-basic.

The fourth setting value may be greater than or equal to the first setting value.

As an example, as shown in fig. 7, the second AC/DC conversion circuit 50 further includes a fifteenth switch Q15, a drain of the fifteenth switch Q15 is respectively connected to the other end of the second inductor L2, one end of the third inductor L3, one end of the fourth capacitor C4, and the second pole of the low-voltage battery L-battery, and a source of the fifteenth switch Q15 is respectively connected to the source of the thirteenth switch Q13, the source of the fourteenth switch Q14, the other end of the fourth capacitor C4, and the second pole of the low-voltage battery L-battery, and is grounded.

In this example, the second inductor L2, the fifteenth switch Q15 and its corresponding freewheeling diode constitute a BOOST circuit, which conditions the voltage of the second AC/DC conversion circuit 50 on the low-voltage battery L-battery side for voltage stabilization.

As an example, as shown in fig. 8, the second AC/DC conversion circuit 50 further includes a sixteenth switch Q16, a drain of the sixteenth switch Q16 is respectively connected to the other end of the fourth capacitor C4 and the second pole of the low-voltage battery L-battery, and in parallel, a source of the sixteenth switch Q16 is respectively connected to a source of the thirteenth switch Q13 and a source of the fourteenth switch Q14.

In this example, the output voltage of the low-voltage battery L-battery can be modulated by the newly added sixteenth switching tube Q16, if the voltage of the low-voltage battery L-battery is not required to be controlled during the operation of the system, the sixteenth switching tube Q16 is kept in a normally open state, and if the voltage of the low-voltage battery L-battery is required to be controlled during the operation of the system, the sixteenth switching tube Q16 operates in a PWM modulation state.

It should be noted that each of the switch tubes may be a MOS (Metal-Oxide-Semiconductor field effect Transistor) tube or an IGBT (Insulated Gate Bipolar Transistor), and referring to fig. 2 to 8, each of the switch tubes is connected in parallel with a freewheeling diode, and the above operation modes of the vehicle-mounted charger are realized by controlling the on or off of the switch tube.

The utility model discloses electric automobile's on-vehicle machine that charges, adopt transformer magnetism integrated technology, with OBC and on-vehicle DC's isolation transformer integrated design, reduce a transformer in the physical structure, OBC and on-vehicle DC share the primary transform circuit of transformer and EMC filter circuit simultaneously, the cost of spare part has been reduced, the volume of spare part has been reduced, the weight of spare part has been lightened, additionally, low voltage battery L-battery output side adopts current doubling circuit, it takes a percentage to make the transformer secondary limit not have the center, the design degree of difficulty of transformer has been reduced, and simultaneously, set up two filter inductance in the current doubling circuit, be favorable to filter inductance's heat dissipation design, power efficiency has been promoted.

As shown in fig. 9, the electric vehicle 1000 includes the vehicle-mounted charger 100 of the electric vehicle of the above embodiment.

The utility model discloses electric automobile adopts the on-vehicle machine that charges of electric automobile of above-mentioned embodiment, and the spare part that uses is few, and spare part is with low costs, and spare part is small, light in weight, and the design degree of difficulty of transformer is low, and power efficiency is high.

In addition, other structures and functions of the electric vehicle according to the embodiment of the present invention are known to those skilled in the art, and are not described herein for reducing redundancy.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.

Claims

1. The utility model provides an electric automobile's on-vehicle machine that charges, electric automobile includes power battery and low-voltage battery, its characterized in that, on-vehicle machine that charges includes:

the alternating current end of the PFC circuit is connected with a power grid;

the direct current end of the DC/AC conversion circuit is connected with the direct current end of the PFC circuit;

the transformer comprises a primary coil, a first secondary coil and a second secondary coil, and the primary coil is connected with the alternating current end of the DC/AC conversion circuit;

the alternating current end of the first AC/DC conversion circuit is connected with the first secondary coil, and the direct current end of the first AC/DC conversion circuit is connected with the power battery;

and the alternating current end of the second AC/DC conversion circuit is connected with the second secondary side coil, and the direct current end of the second AC/DC conversion circuit is connected with the low-voltage storage battery.

2. The vehicle-mounted charger of the electric vehicle according to claim 1, wherein the PFC circuit comprises:

one end of the first capacitor is connected with a live wire of the power grid, and the other end of the first capacitor is connected with a zero line of the power grid;

one end of the first inductor is respectively connected with one end of the first capacitor and a live wire of the power grid;

the middle point of the first bridge arm is connected with the other end of the first inductor, and the first bridge arm comprises a first switching tube and a second switching tube which are connected in series;

and the midpoint of the second bridge arm is respectively connected with the other end of the first capacitor and a zero line of the power grid, the second bridge arm and the first bridge arm are connected in parallel to form a first bus end and a second bus end, the first bus end is connected with a first port of a direct current end of the DC/AC conversion circuit, the second bus end is connected with a second port of the direct current end of the DC/AC conversion circuit and is grounded, and the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series.

3. The vehicle-mounted charger according to claim 2, further comprising:

and the second capacitor is connected between the PFC circuit and the DC/AC conversion circuit, one end of the second capacitor is connected with the first bus bar end, and the other end of the second capacitor is connected with the second bus bar end.

4. The vehicle-mounted charger according to claim 1, wherein the DC/AC conversion circuit comprises:

the middle point of the third bridge arm is connected with one end of the primary coil, and the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the middle point of the fourth bridge arm is connected with the other end of the primary coil, the fourth bridge arm and the third bridge arm are connected in parallel to form a third bus end and a fourth bus end, the third bus end is connected with a first port of a direct current end of the PFC circuit, the fourth bus end is connected with a second port of the direct current end of the PFC circuit and is grounded, and the fourth bridge arm comprises a seventh switch tube and an eighth switch tube which are connected in series.

5. The vehicle-mounted charger according to claim 1, wherein the first AC/DC conversion circuit comprises:

the middle point of the fifth bridge arm is connected with one end of the first secondary coil, and the fifth bridge arm comprises a ninth switching tube and a tenth switching tube which are connected in series;

the middle point of the sixth bridge arm is connected with the other end of the first secondary coil, the sixth bridge arm and the fifth bridge arm are connected in parallel to form a fifth junction end and a sixth junction end, the fifth junction end is connected with the first pole of the power battery, the sixth junction end is connected with the second pole of the power battery and is grounded, and the sixth bridge arm comprises an eleventh switching tube and a twelfth switching tube which are connected in series;

and one end of the third capacitor is connected with the fifth bus end and the first pole of the power battery respectively, and the other end of the third capacitor is connected with the sixth bus end and the second pole of the power battery respectively and grounded.

6. The vehicle-mounted charger according to claim 1, wherein the second AC/DC conversion circuit comprises:

a thirteenth switching tube, a drain of which is connected to one end of the second secondary winding, and a source of which is connected to the second pole of the low-voltage battery and grounded;

a fourteenth switching tube, a source of which is connected to the source of the thirteenth switching tube and the second pole of the low-voltage battery, respectively, and is grounded, and a drain of which is connected to the other end of the second secondary winding;

one end of the second inductor is connected with the drain electrode of the thirteenth switching tube and one end of the second secondary side coil respectively, and the other end of the second inductor is connected with the first pole of the low-voltage storage battery;

one end of the third inductor is connected with the other end of the second inductor and the first pole of the low-voltage storage battery respectively, and the other end of the third inductor is connected with the drain electrode of the fourteenth switching tube;

and one end of the fourth capacitor is connected with the other end of the second inductor, one end of the third inductor and the first pole of the low-voltage storage battery respectively, and the other end of the fourth capacitor is connected with the source electrode of the thirteenth switch tube, the source electrode of the fourteenth switch tube and the second pole of the low-voltage storage battery respectively and grounded.

7. The vehicle-mounted charger according to claim 6, wherein the second AC/DC conversion circuit further comprises:

a fifteenth switch tube, a drain of which is connected to the other end of the second inductor, one end of the third inductor, one end of the fourth capacitor, and the second pole of the low-voltage battery, respectively, and a source of which is connected to the source of the thirteenth switch tube, the source of the fourteenth switch tube, the other end of the fourth capacitor, and the second pole of the low-voltage battery, and is grounded, respectively.

8. The vehicle-mounted charger according to claim 6, wherein the second AC/DC conversion circuit further comprises:

and a drain of the sixteenth switching tube is connected to the other end of the fourth capacitor and the second pole of the low-voltage battery, respectively, and is grounded, and a source of the sixteenth switching tube is connected to the source of the thirteenth switching tube and the source of the fourteenth switching tube, respectively.

9. The vehicle-mounted charger according to claim 4, further comprising:

one end of the fourth inductor is connected with the midpoint of the third bridge arm, and the other end of the fourth inductor is connected with one end of the primary coil;

and one end of the fifth capacitor is connected with the midpoint of the fourth bridge arm, and the other end of the fifth capacitor is connected with the other end of the primary coil.

10. An electric vehicle, characterized in that it comprises an on-board charger for electric vehicles according to any one of claims 1 to 9.