CN112572191B

CN112572191B - Vehicle-mounted charging system and vehicle with same

Info

Publication number: CN112572191B
Application number: CN201910935319.6A
Authority: CN
Inventors: 许兴发; 吴昊; 刘宇; 杨柳
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2022-03-15
Anticipated expiration: 2039-09-29
Also published as: CN112572191A

Abstract

The invention discloses a vehicle-mounted charging system and a vehicle with the same, wherein the vehicle-mounted charging system comprises a first resonant circuit module, a second resonant circuit module, a direct current conversion circuit module and a control module, wherein the first resonant circuit module is used for converting an electric signal in a first half period of power supply; the second resonance circuit module carries out conversion processing on the electric signal of the second half period of power supply; the first resonant circuit module and the second resonant circuit module multiplex a second conversion unit, and the direct current conversion circuit module performs direct current-direct current conversion on the input electric signal; the control module controls the first resonant circuit module to be gated when the power is supplied for a first half period, controls the first resonant circuit module according to the timing signal of the first half period of the power supply, controls the second resonant circuit module to be gated when the power is supplied for a second half period, and controls the second resonant circuit module according to the timing signal of the second half period of the power supply. The system and the vehicle adopt a design without electrolytic capacitors, so that the cost can be reduced, and the stability can be improved.

Description

Vehicle-mounted charging system and vehicle with same

Technical Field

The invention relates to the technical field of vehicles, in particular to a vehicle-mounted charging system and a vehicle with the same.

Background

Fig. 1 is a circuit diagram of a vehicle charging system in the related art, which is connected to a power grid at one end and a battery pack at the other end, and includes a Part1 'and a Part 2' two-stage circuit. When the battery is charged in the forward direction, Part 1' realizes alternating current-direct current conversion and power factor correction, and outputs direct current voltage. Part 2' is a dc-dc converter that outputs the appropriate voltage to charge the battery pack. For the system, in order to provide stable input direct-current voltage for the later stage Part2 ', a large-capacity electrolytic capacitor C1 ' is needed between Part1 ' and Part2 ', so that the volume and the cost of the system are increased, and the electrolytic capacitor C1 ' has the problems of service life and shock resistance and is unfavorable for the reliability of the system.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide an onboard charging system that does not require a large-capacity electrolytic capacitor, reduces the system size, reduces the cost, and improves the system stability.

The invention further provides a vehicle adopting the vehicle-mounted charging system.

In order to solve the above problem, an in-vehicle charging system according to an embodiment of a first aspect of the present invention includes: the first resonant circuit module is used for converting an electric signal of a first half cycle of power supply, and comprises a first conversion unit, a first transformer and a second conversion unit, wherein the first conversion unit comprises a first switching tube and a second switching tube, a first end of the first switching tube is connected with a first end of the electric unit, a second end of the first switching tube is connected with a first end of the second switching tube, the first transformer comprises a first coil and a second coil, the first coil is connected with the first conversion unit, and a first end of the second coil is connected with the second conversion unit; the second resonant circuit module is used for converting an electric signal of a second half period of power supply, and comprises a third conversion unit, a second transformer and the second conversion unit, wherein the third conversion unit comprises a third switching tube and a fourth switching tube, a first end of the third switching tube is connected with a second end of the electric unit, a second end of the third switching tube is connected with a first end of the fourth switching tube, a second end of the fourth switching tube is connected with a second end of the second switching tube, the second transformer comprises a third coil and a fourth coil, the third coil is connected with the third conversion unit, a first end of the fourth coil is connected with a second end of the second coil, and a second end of the fourth coil is connected with the second conversion unit; the direct current conversion circuit module is respectively connected with the second conversion unit and the battery pack and is used for performing direct current-direct current conversion on an input electric signal; and the control module is used for controlling the third switching tube and the fourth switching tube to be kept conductive during a first half period of power supply and controlling the first resonant circuit module according to a timing signal of the first half period of power supply, or controlling the first switching tube and the second switching tube to be kept conductive during a second half period of power supply and controlling the second resonant circuit module according to a timing signal of the second half period of power supply.

According to the vehicle-mounted charging system provided by the embodiment of the invention, the control module controls the gating of the first resonant circuit module and the second resonant circuit module according to the power supply periodic signal by arranging the two resonant circuits, so that the signal output to the conversion circuit module by the resonant circuit module is a steamed bread wave, therefore, the system does not need a large-capacity electrolytic capacitor for filtering, adopts a non-electrolytic capacitor design, only needs a small-capacity capacitor, reduces the cost and the volume of the electrolytic capacitor part, improves the reliability and the service life of the system, and the serial conduction of the self switch tube in the resonance circuit is used for gating, a gating circuit module is not needed, in addition, the two-path resonant circuit multiplexes the second conversion unit, so that fewer circuit devices can be adopted, the cost is reduced, and the direct current conversion circuit module is arranged at the rear, so that the charging voltage range is widened, and the charging efficiency is improved.

In order to solve the above problem, a vehicle according to an embodiment of a second aspect of the present invention includes a battery pack and the vehicle-mounted charging system.

According to the vehicle provided by the embodiment of the invention, the vehicle-mounted charging system provided by the embodiment of the invention is adopted, so that the cost can be reduced, the reliability is improved, the shock resistance is improved, and the charging efficiency is improved.

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

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a circuit diagram of a bidirectional vehicle-mounted charger in the related art;

FIG. 2 is a functional block diagram of an in-vehicle charging system according to one embodiment of the present invention;

FIG. 3 is a waveform diagram of an input-output electrical signal of a resonant circuit according to an embodiment of the present invention;

FIG. 4 is a functional block diagram of an in-vehicle charging system according to one embodiment of the present invention;

fig. 5 is a circuit diagram of an in-vehicle charging system according to an embodiment of the invention;

fig. 6 is a circuit diagram of an in-vehicle charging system according to another embodiment of the invention;

fig. 7 is a circuit diagram of an in-vehicle charging system according to an embodiment of the invention;

fig. 8 is a circuit diagram of an in-vehicle charging system according to another embodiment of the invention;

FIG. 9 is a block diagram of a vehicle according to one embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

An in-vehicle charging system according to an embodiment of the invention is described below with reference to fig. 2 to 8.

Fig. 2 is a block diagram of an in-vehicle charging system according to an embodiment of the present invention, and as shown in fig. 2, the in-vehicle charging system 100 of the embodiment of the present invention includes a first resonant circuit module 10, a second resonant circuit module 20, a dc conversion circuit module 30, and a control module 40.

The first resonant circuit module 10 is configured to perform conversion processing on an electrical signal of a first half cycle of power supply, and the first resonant circuit module 10 includes a first conversion unit 11, a first transformer T1, and a second conversion unit 12, where in an embodiment, the first conversion unit 11 may be configured to perform conversion between an alternating current first half cycle signal and an alternating current, the second conversion unit 12 may implement conversion between an alternating current and a direct current, and the first transformer T1 plays roles of signal isolation and transmission. The first switching unit 11 includes a first switching tube Q1 and a second switching tube Q2, a first end of the first switching tube Q1 is connected to a first end of the electric unit 50, and a second end of the first switching tube Q1 is connected to a first end of the second switching tube Q2. The first transformer T1 includes a first coil W1 and a second coil W2, the first coil W1 is connected to the first converting unit 11, and a first end of the second coil W2 is connected to the second converting unit 12.

The second resonant circuit module 20 is used for performing conversion processing on the electrical signal of the second half period of the power supply, and the second resonant circuit module 20 includes a third conversion unit 21, a second transformer T2, and a fourth conversion unit 22, wherein in an embodiment, the third conversion unit 21 may be used for performing conversion between the signal of the second half period of the alternating current and the alternating current, the fourth conversion unit 22 may perform conversion between the alternating current and the direct current, and the second transformer T2 plays a role in signal isolation and transmission. The third conversion unit 21 includes a third switching tube Q3 and a fourth switching tube Q4, a first end of the third switching tube Q3 is connected to a second end of the electric unit 50, a second end of the third switching tube Q3 is connected to a first end of the fourth switching tube Q4, and a second end of the fourth switching tube Q4 is connected to a second end of the second switching tube Q2. The second transformer T2 includes a third coil W3 and a fourth coil W4, the third coil W3 being connected to the third conversion unit 21, a first end of the fourth coil W4 being connected to a second end of the second coil W2, and a second end of the fourth coil W4 being connected to the second conversion unit 12.

That is, the first resonant circuit module 10 and the second resonant circuit module 20 multiplex the second converting unit 12, so that fewer circuit devices can be adopted, and the cost can be reduced. In an embodiment, the electrical unit 50 may include an electrical grid, a consumer, and the like. In some embodiments, the ac-dc conversion may include dc to ac or ac to dc conversion.

The dc conversion circuit module 30 is used for performing dc-dc conversion on the input electrical signal, for example, reducing a dc voltage or boosting a dc voltage. In some embodiments, the dc conversion circuit module 30 may employ a BOOST circuit. The dc conversion circuit module 30 is connected to the second conversion unit 12 and the battery pack 60, respectively.

The control module 50 is configured to control the third switching transistor Q3 and the fourth switching transistor Q4 to remain conductive during a first half period of power supply to gate the first resonant circuit module 10 and control the first resonant circuit module 10 according to a timing signal during the first half period of power supply, or control the first switching transistor Q1 and the second switching transistor Q2 to remain conductive during a second half period of power supply to gate the second resonant circuit module 20 and control the second resonant circuit module 20 according to a timing signal during the second half period of power supply.

Specifically, when charging is performed, the electrical unit 50 may be a power grid, and the control module 40 detects cycle information of the alternating current output by the power grid, and controls the third switching tube Q3 and the fourth switching tube Q4 to remain conductive during a first half cycle, for example, a positive half cycle, of power supply, where the first end of the first resonant circuit module 10 is connected to the first end of the power grid, and the second end of the first resonant circuit module 10 is connected to the second end of the power grid, that is, the first resonant circuit module 10 is gated. The power grid outputs electric energy to the first conversion unit 11 of the first resonant circuit module 10, the first conversion unit 11 converts the electric signal of the positive half cycle of the power grid into alternating current voltage, the alternating current voltage is isolated by the first transformer T1 and then transmitted to the second conversion unit 12, the second conversion unit 12 rectifies the input electric signal, converts the alternating current signal into direct current and outputs the direct current to the direct current conversion circuit module 30, the direct current conversion circuit module 30 converts the input direct current into direct current voltage required by the battery pack 60, and the charging of the battery pack 60 by the electric signal of the positive half cycle of the power grid is realized.

Similarly, when the control module 50 detects a second half-cycle, for example, a negative half-cycle, of the power supply, the first switching tube Q1 and the second switching tube Q2 are controlled to remain conductive, and the first end of the second resonant circuit module 20 is connected to the second end of the power grid, and the second end of the second resonant circuit module 20 is connected to the first end of the power grid, that is, the second resonant circuit module 20 is gated. The power grid supplies power to the second resonant circuit module 20, that is, the second resonant circuit module 20 is gated when the power grid outputs a negative half cycle, the third conversion unit 21 of the second resonant circuit module 20 converts the electric signal of the negative half cycle of the power grid into an alternating current voltage and transmits the alternating current voltage to the second conversion unit 12 through the second transformer T2, the second conversion unit 12 converts the alternating current into a direct current and outputs the direct current to the direct current conversion circuit module 30, and the direct current conversion circuit module 30 converts the input direct current into a direct current voltage required by the battery pack 60 to charge the battery pack 60.

As shown in fig. 3, the electrical signal provided by the power grid 50 is as shown in (a) of fig. 3, during the positive half-cycle, the control module 40 controls the first end and the second end of the second resonant circuit module 20 to be conducted in series to gate the first resonant circuit module 10, the electrical signal input to the first resonant circuit module 10 is as shown in (b) of fig. 3, and the electrical signal output by the first resonant circuit module 10 is as shown in (d) of fig. 3. And, during the negative half cycle, the control module 50 controls the first end and the second end of the first resonant circuit module 20 to be connected in series and conducted, so as to gate the second resonant circuit module 20, the input electrical signal of the second resonant circuit module 20 is shown in (c) of fig. 3, and the second resonant circuit module 20 converts the electrical signal into a pulsating direct current signal, the output electrical signal of the second resonant circuit module 20 is shown in (e) of fig. 3, the waveform of the electrical signal provided to the direct current conversion circuit module 30 is shown in (f) of fig. 3, that is, the input electrical signal provided to the direct current conversion circuit module 30 is a steamed bread wave, so that filtering by using an electrolytic capacitor with a large capacity is not required, filtering by using a capacitor unit with a small capacity is required, and cost and system volume are reduced.

In addition, in the embodiment of the present application, the gating circuit may be omitted, and the control module 40 controls the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, and the fourth switching tube Q4 according to the power supply period signal to gate the resonant circuit, so that circuit devices may be saved, and the cost may be reduced.

According to the vehicle-mounted charging system 100 of the embodiment of the invention, by arranging two resonant circuits of the first resonant circuit module 10 and the second resonant circuit module 20, during the first half period of power supply, the control module 40 controls the switching tube in the second resonant circuit module 20 to be conducted in series, so that the first end and the second end of the switching tube are conducted in series, namely, the first resonant circuit module 10 is gated, and during the second half period of power supply, the control module 40 controls the first end and the second end of the first resonant circuit module 10 to be conducted in series, namely, the second resonant circuit module 20 is gated, so that the input electric signal provided by the resonant circuit module to the dc conversion circuit module 30 is a steamed bread wave, thereby filtering can be performed by using a small-capacity capacitor device, a large-capacity electrolytic capacitor is not required, the volume and cost of the system can be reduced, a non-electrolytic capacitor design is adopted, and the service life of the electrolytic capacitor is not required to be considered, The anti-seismic problem is favorable for providing the stability of the charging system, the first resonant circuit module 10 and the second resonant circuit module 20 multiplex the second conversion unit 12, fewer circuit devices can be adopted, the cost is reduced, and the gating of two resonant circuits can be realized without arranging a special gating circuit module, so that the cost is reduced.

In some embodiments, for the vehicle-mounted charging system provided with the gating circuit module in the related art, gating is realized by independently controlling the switching tube in the gating circuit module, so that a large conduction loss is generated, and therefore, the system provided by the embodiment of the invention is improved on the basis.

As shown in fig. 4, the vehicle-mounted charging system 100 according to the embodiment of the invention may further include a gating circuit module 70, wherein the gating circuit module 70 includes a fifth switching tube Q5 and a sixth switching tube Q6. A first end of a fifth switching tube Q5 is connected to the first end of the electric unit 50, a second end of the fifth switching tube Q5 is connected to the second end of the second switching tube Q2 and the second end of the fourth switching tube Q4, respectively, a first end of a sixth switching tube Q6 is connected to the second end of the electric unit 50, and a second end of a sixth switching tube Q6 is connected to the second end of the second switching tube Q2 and the second end of the fourth switching tube Q4, respectively. The control module 40 is further configured to control the fifth switching tube Q5 to turn off and the sixth switching tube Q6 to turn on during a first half period of power supply, or control the fifth switching tube Q5 to turn on and the sixth switching tube Q6 to turn off during a second half period of power supply.

Specifically, referring to fig. 4, for example, when the positive half-cycle signal of the power grid occurs, the control module 40 controls the third switching tube Q3 and the fourth switching tube Q4 to remain on, and controls the fifth switching tube Q5 to turn off, and controls the sixth switching tube Q6 to turn on, that is, the third switching tube Q3 and the fourth switching tube Q4 are connected in series and then connected in parallel with the sixth switching tube Q6, so that the second end of the first resonant circuit module 10 can be connected to the power grid, and the first resonant circuit module 10 is gated, compared with the case of controlling the sixth switching tube or the fifth switching tube to be on separately (specifically, the resistance of the sixth switching tube is greater than the resistance of the sixth switching tube connected in parallel to the third switching tube and the fourth switching tube after series connection), so as to reduce conduction loss. Similarly, during the negative half cycle of the power grid, the control module 40 controls the first switching tube Q1 and the second switching tube Q2 to remain on, controls the fifth switching tube Q5 to be on, and controls the sixth switching tube Q6 to be off, so that the second end of the second resonant circuit module 20 is connected with the first end of the power grid, and the gating of the second resonant circuit module 20 is realized, thereby reducing the conduction loss.

The circuit structure of each module according to the embodiment of the present invention is further described below with reference to the drawings.

In some embodiments, fig. 5 is a circuit diagram of an onboard charging system in accordance with an embodiment of the present invention, wherein the electrical unit 50 is an electrical grid. In an embodiment, as shown in fig. 5, the first resonant circuit module 10 and the second resonant circuit module 20 may employ a symmetrical half-bridge LLC resonant circuit to implement isolation and voltage regulation, and perform ac-dc conversion on the input electrical signal.

As shown in fig. 5, the first conversion unit 11 includes a first capacitor C1, a first switch tube Q1, a second switch tube Q2, a second capacitor C2, and a third capacitor C3, and the second conversion unit 12 includes a seventh switch tube Q7, an eighth switch tube Q8, a ninth switch tube Q9, and a tenth switch tube Q10.

A first terminal of the first capacitor C1 is connected to the first terminal of the electric unit 50, and a second terminal of the first capacitor C1 is connected to the second terminal of the second switch Q2. The first capacitor C1 may filter the input electrical signal of the first resonant circuit module 10 to reduce electrical signal interference.

A first end of a first switch tube Q1 is connected to a first end of a first capacitor C1 and a first end of the electrical unit 50, a control end of the first switch tube Q1 is connected to the control module 40, a second end of the first switch tube Q1 is connected to a first end of a second switch tube Q2, a second end of the second switch tube Q2 is connected to a second end of a first capacitor C1 and a second end of a fourth switch tube Q4, a control end of the second switch tube Q2 is connected to the control module 40, and a first node O1 is provided between the second end of the first switch tube Q1 and the first end of the second switch tube Q2. A first terminal of the second capacitor C2 is connected to a first terminal of a third capacitor C3, a second terminal of the third capacitor C3 is connected to a second terminal of the second switch Q2, and a second node O2 is located between the second terminal of the second capacitor C2 and the first terminal of the third capacitor C3.

A first terminal of a first winding W1 of the first transformer T1 is connected to a first node O1 through a first inductor L1, and a second terminal of the first winding W1 is connected to a second node O2.

A first end of the seventh switching tube Q7 is connected to the first end of the dc conversion circuit module 30, a control end of the seventh switching tube Q7 is connected to the control module 50, a second end of the seventh switching tube Q7 is connected to the first end of the eighth switching tube Q8, a second end of the eighth switching tube Q8 is connected to the second end of the dc conversion circuit module 30, a control end of the eighth switching tube Q8 is connected to the control module 40, a third node O3 is located between the second end of the seventh switching tube Q7 and the first end of the eighth switching tube Q8, and the third node O3 is connected to the first end of the second coil W2 through the second inductor L2. A first end of the ninth switching tube Q9 is connected to the first end of the seventh switching tube Q7 and the first end of the dc conversion circuit module 30, a second end of the ninth switching tube Q9 is connected to the first end of the tenth switching tube Q10, a control end of the ninth switching tube Q9 is connected to the control module 40, a second end of the tenth switching tube Q10 is connected to the first end of the eighth switching tube Q8 and the second end of the dc conversion circuit module 30, a fourth node O4 is located between the second end of the ninth switching tube Q9 and the first end of the tenth switching tube Q10, and the fourth node O4 is connected to the second end of the fourth winding W4. In the charging mode, the seventh switch tube Q7, the eighth switch tube Q8, the ninth switch tube Q9 and the tenth switch tube Q10 may form a rectifying circuit structure, and in the discharging mode, the seventh switch tube Q7, the eighth switch tube Q8, the ninth switch tube Q9 and the tenth switch tube Q10 may form an inverter circuit structure.

As shown in fig. 5, the third converting unit 21 includes a fourth capacitor C4, a third switching tube Q3, a fourth switching tube Q4, a fifth capacitor C5, and a sixth capacitor C6.

A first terminal of the fourth capacitor C4 is connected to the second terminal of the electrical unit 50, and a second terminal of the fourth capacitor C4 is connected to the second terminal of the second switch Q2 and the second terminal of the fourth switch Q4, respectively.

A first terminal of a third switching tube Q3 is connected to a first terminal of a fourth capacitor C4, a control terminal of the third switching tube Q3 is connected to the control module 50, a second terminal of the third switching tube Q3 is connected to a first terminal of a fourth switching tube Q4, a second terminal of the fourth switching tube Q4 is connected to a second terminal of the fourth capacitor C4, a control terminal of the fourth switching tube Q4 is connected to the control module 40, and a fifth node O5 is provided between the second terminal of the third switching tube Q3 and the first terminal of the fourth switching tube Q4.

A first terminal of the fifth capacitor C5 is connected to the first terminal of the third switching transistor Q3, a second terminal of the fifth capacitor C5 is connected to the first terminal of the sixth capacitor C6, a second terminal of the sixth capacitor C6 is connected to the second terminal of the fourth switching transistor Q4, and a sixth node O6 is located between the second terminal of the fifth capacitor C5 and the first terminal of the sixth capacitor C6.

A first terminal of a third coil T3 of the second transformer T2 is connected to a fifth node O5 through a third inductor L3, a second terminal of the third coil W3 is connected to a sixth node O6, a first terminal of a fourth coil W4 of the second transformer T2 is connected to a second terminal of the second coil W2 through a seventh capacitor C7, and a second terminal of the fourth coil W4 is connected to a fourth node O4

Fig. 5 is a circuit diagram of an in-vehicle charging system without a gating circuit module according to an embodiment of the present invention, as shown in fig. 6, which is a circuit diagram of an in-vehicle charging system including a gating circuit module according to an embodiment of the present invention, wherein, as described above, the gating circuit module 70 includes the fifth switching tube Q5 and the sixth switching tube Q6, and the control module 40 controls the gating circuit module 70 and the switching tubes that are conducted in series according to the power supply cycle signal, so as to implement the gating of the resonant circuit. As shown in fig. 6, other circuit modules, such as the first resonant circuit module 10, the second resonant circuit module 20, and the dc conversion circuit module 30, have the same circuit structure as that in fig. 5, and reference may be made to the description in fig. 5, which is not repeated herein.

Specifically, referring to fig. 5, when the battery pack 60 is charged, during the first half cycle of power supply, when the grid voltage is in the positive half cycle, the control module 40 controls the third switching tube Q3 and the fourth switching tube Q4 to remain on, or, as shown in fig. 6, controls the third switching tube Q3, the fourth switching tube Q4 and the sixth switching tube Q6 to remain on, and controls the fifth switching tube Q5 to turn off, the first resonant circuit module 10 is turned on; the grid voltage is applied to the first capacitor C1, the control module 40 turns on or off the first switch tube Q1 and the second switch tube Q2 at a fixed frequency and a fixed duty cycle, and the second capacitor C2 and the third capacitor C3 are charged or discharged, so that an alternating voltage is formed between a midpoint of the first switch tube Q1 and the second switch tube Q2, namely a first node O1, and a midpoint of the second capacitor C2 and the third capacitor C3, namely a second node O2. After the alternating current signal is isolated by the first transformer T1, the alternating current signal is transmitted to a rectifying circuit composed of a seventh switching tube Q7, an eighth switching tube Q8, a ninth switching tube Q9 and a tenth switching tube Q10, and by controlling on/off of the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9 and the tenth switching tube Q10, the alternating current voltage between a midpoint of the seventh switching tube Q7 and the eighth switching tube Q8, i.e., a third node O3, and a midpoint of the ninth switching tube Q9 and the tenth switching tube Q10, i.e., a fourth node O4, is converted into a direct current voltage output, i.e., a voltage provided to the direct current conversion circuit module 30, so that alternating current-direct current conversion of the positive signal of the power grid is realized.

Similarly, as shown in fig. 5, during the second half period of the power supply, for example, when the grid voltage is a negative half period, the control module 40 controls the first switching tube Q1 and the second switching tube Q2 to be kept conductive, or, as shown in fig. 6, the control module 40 controls the first switching tube Q1 and the second switching tube Q2, and the fifth switching tube Q5 to be kept conductive, and controls the sixth switching tube Q6 to be turned off, the second resonant circuit module 20 is enabled, and the first resonant circuit module 10 is not operated; the grid voltage is applied to the fourth capacitor C4, and the control module 40 controls the third switch tube Q3 and the fourth switch tube Q4 to be turned on or off at a fixed frequency and a fixed duty ratio, and charges or discharges the fifth capacitor C5 and the sixth capacitor C6, so that an alternating voltage is formed between a midpoint of the third switch tube Q3 and the fourth switch tube Q4, i.e., the fifth node O5, and a midpoint of the fifth capacitor C5 and the sixth capacitor C6, i.e., the sixth node O6. After the alternating current signal is isolated by the second transformer T2, the alternating current signal is transmitted to a rectification circuit composed of a seventh switching tube Q7, an eighth switching tube Q8, a ninth switching tube Q9 and a tenth switching tube Q10, the control module 40 controls the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9 and the tenth switching tube Q10 to be turned on or off, and converts the alternating current voltage between the midpoint of the seventh switching tube Q7 and the eighth switching tube Q8, i.e., the third node O3, and the midpoint of the ninth switching tube Q9 and the tenth switching tube Q10, i.e., the fourth node O4, into a direct current voltage to be output, so as to realize the alternating current-direct current conversion of the negative half-cycle electrical signal of the power grid.

As shown in fig. 5 or fig. 6, the dc conversion circuit module 30 includes an eighth capacitor C8, an eleventh switch Q10, a twelfth switch Q12, and a ninth capacitor C9.

In the embodiment of the present invention, the control module 40 gates the resonant circuit according to the power supply period signal, so that the electrical signal input to the dc conversion circuit module 30 is an steamed bread wave, and therefore, a large-capacity electrolytic capacitor is not needed for filtering, and the eighth capacitor C8 may be a small-capacity capacitor device, such as a thin-film capacitor. A first end of the eighth capacitor C8 is connected to the first end of the seventh switch Q7, the first end of the fourth capacitor C4, the first end of the ninth switch Q9, and the first end of the ninth capacitor C9, respectively, and a second end of the eighth capacitor C8 is connected to the second end of the eighth switch Q8, the second end of the fifth capacitor C5, the second end of the tenth switch Q10, and the second end of the tenth capacitor C10, respectively.

A first end of an eleventh switch tube Q11 is connected to the first end of the battery pack 60, a control end of an eleventh switch tube Q11 is connected to the control module 40, a second end of the eleventh switch tube Q11 is connected to the first end of a twelfth switch tube Q12, a control end of the eleventh switch tube Q11 is connected to the control module 40, a second end of a twelfth switch tube Q12 is connected to the second end of the eighth capacitor C8 and the second end of the battery pack 60, a control end of the twelfth switch tube Q12 is connected to the control module 40, a ninth node O9 is provided between the second end of the eleventh switch tube Q11 and the first end of the twelfth switch tube Q12, and the ninth node O9 is connected to the first end of the eighth capacitor C8 through a fifth inductor L4; a first end of the ninth capacitor C9 is connected to the first end of the eleventh switch transistor Q11 and the first end of the battery pack 60, respectively, a second end of the ninth capacitor C9 is connected to the second end of the twelfth switch transistor Q12 and the second end of the battery pack 60, respectively, and the ninth capacitor C9 plays a role in filtering.

In the present embodiment, the dc conversion circuit module 30 is disposed in the rear, so that the charging voltage or the charging power output to the battery pack 60 can be adjusted by controlling the duty ratio of the dc conversion circuit module 30, thereby not only widening the voltage range of the adaptive battery pack, but also shortening the charging time of the battery and the charging efficiency of the battery pack 60, and realizing power factor correction.

The dc conversion circuit module 30 regulates the input dc voltage to supply to the battery pack 60. Specifically, when the twelfth switching tube Q12 is turned on, the current of the fourth inductor L4 increases, and as shown in fig. 5 or 6, the current flows in a → L4 → Q12 → B; the twelfth switching tube Q12 is turned off, the current of the fourth inductor L4 decreases, and the current flows in a → L4 → Q11 → battery pack → B as shown in fig. 5 or 6. The twelfth switching tube Q12 is controlled by the control module 40 to switch on and off at a high frequency, so that the current waveform of the fourth inductor L4 tracks the voltage of the eighth capacitor C8, thereby achieving power factor correction, and the current amplitude of the fourth inductor L4 depends on the charging power.

The voltage of the eighth capacitor C8 is proportional to the absolute value of the grid voltage, and the voltage waveform output by the first resonant circuit module 10 and the second resonant circuit module 20 is the steamed bread wave, so that a large-capacity electrolytic capacitor is not needed for filtering, and the eighth capacitor C8 can be a small-capacity capacitor, such as a film capacitor, thereby reducing the cost and the system volume.

Based on the circuit structure of the vehicle-mounted charging system 100 shown in fig. 5 and 6, the vehicle-mounted charging system can also operate in a discharging mode, that is, the battery pack 60 is discharged, and the specific process includes that the battery pack 60 outputs an electrical signal, the dc conversion is performed through the dc conversion circuit module 30, and further the ac electrical signal is output through the gating of the first resonant circuit module 10 and the second resonant circuit module 20 to supply power to the electric device, which includes the following specific processes.

When the vehicle-mounted charging system 100 works in the discharging mode, the battery pack 60 discharges and outputs direct current, the direct current conversion circuit module 30 performs direct current-direct current conversion to realize the voltage regulation function, and the control module 40 gates the first resonance circuit module 10 or the second resonance circuit module 20 according to the power supply period signal to output power frequency alternating current to supply power to the electric equipment or feed back the power frequency alternating current to the power grid.

Referring to fig. 5 or 6, specifically, the switching timing of the dc conversion circuit module 30 is: when the eleventh switch tube Q11 is turned on, the current of the fourth inductor L4 rises, and the battery pack 60 transfers energy to the rear-stage circuit; when the eleventh switch Q11 is turned off, the current of the fourth inductor L4 drops, and then flows through the twelfth switch Q12, and energy is transferred to the subsequent stage. The control module 40 regulates the output voltage, i.e., the voltage across the eighth capacitor C8, by controlling the eleventh switch Q11 to turn on and off, and the voltage amplitude depends on the switching duty cycle of the eleventh switch Q11 and the voltage of the battery pack 60.

For the first resonant circuit module 10 and the second resonant circuit module 20, the first resonant circuit module 10 is gated on outputting a positive half cycle of the alternating current. Specifically, the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9 and the tenth switching tube Q10 are controlled to be turned on or off at a fixed frequency and a fixed duty ratio, and an alternating voltage is formed between a midpoint of the seventh switching tube Q7 and the eighth switching tube Q8, i.e., the third node O3, and a midpoint of the ninth switching tube Q9 and the tenth switching tube Q10, i.e., the fourth node O4. After the isolation of the first transformer T1, the first switch tube Q1, the second switch tube Q2, the second capacitor C2 and the third capacitor C3 realize a rectification function, and through the on or off of the first switch tube Q1 and the second switch tube Q2 and the charging or discharging of the second capacitor C2 and the third capacitor C3, the alternating-current voltage between the midpoint of the first switch tube Q1 and the second switch tube Q2, namely the first node O1, and the midpoint of the second capacitor C2 and the third capacitor C3, namely the second node O2, is converted into a positive half-cycle part of the power-frequency alternating current, namely voltages at two ends of the first capacitor C1, so that the positive half-cycle part output of the power-frequency alternating current is realized.

Similarly, when the system outputs a negative half cycle of the alternating current, the second resonant circuit module 20 is gated to control the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9 and the tenth switching tube Q10 to be turned on or off at a fixed frequency and a fixed duty ratio, and an alternating voltage is formed between a midpoint of the seventh switching tube Q7 and the eighth switching tube Q8, i.e., the third node O3, and a midpoint of the ninth switching tube Q9 and the tenth switching tube Q10, i.e., the fourth node O4. After the transformation and isolation of the second transformer T2, the alternating current signal is transmitted to a rectifying circuit composed of a third switching tube Q3, a fourth switching tube Q4, a fifth capacitor C5 and a sixth capacitor C6, and the alternating current voltage between the midpoint of the third switching tube Q3 and the fourth switching tube Q4, i.e., the fifth node O5, and the midpoint of the fifth capacitor C5 and the sixth capacitor C6, i.e., the sixth node O6, is converted into the negative half-cycle of the power frequency alternating current, i.e., the voltage at both ends of the fourth capacitor C4, by the conduction or the disconnection of the third switching tube Q3 and the fourth switching tube Q4, and the charging or the discharging of the fifth capacitor C5 and the sixth capacitor C6, so as to realize the negative half-cycle output of the power frequency alternating current.

The bidirectional charging circuit structure of the vehicle-mounted charging system 100 of the embodiment of the present invention is described above, and in some embodiments, the vehicle-mounted charging system 100 of the embodiment of the present invention further includes a unidirectional charging circuit structure.

Fig. 7 is a circuit diagram of an in-vehicle charging system according to an embodiment of the present invention, and fig. 8 is a circuit diagram of an in-vehicle charging system according to another embodiment of the present invention, in which the gate circuit module 70 is not included in fig. 7, the gate circuit module 70 is included in fig. 8, and other circuit configurations are the same, and an in-vehicle charging system 100 according to an embodiment of the present invention will be described below with reference to fig. 7 and 8.

As shown in fig. 7 or 8, the first conversion unit 11 includes a tenth capacitor C10, a first switch Q1, a second switch Q2, an eleventh capacitor C11, and a twelfth capacitor C12, and the second conversion unit 12 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

A first terminal of the tenth capacitor C10 is connected to the first terminal of the electrical unit 50, for example, the grid, and a second terminal of the tenth capacitor C10 is connected to the second terminal of the second switch tube Q2. The tenth capacitor C10 is used to filter the electrical signal from the grid input to reduce interference.

A first end of a first switching tube Q1 is connected to a first end of the electric unit 50 and a first end of a tenth capacitor C10, respectively, a control end of the first switching tube Q1 is connected to the control module 40, a second end of the first switching tube Q1 is connected to a first end of a second switching tube Q2, a second end of the second switching tube Q2 is connected to a second end of the tenth capacitor C10 and a second end of the fourth switching tube Q4, respectively, a control end of the second switching tube Q2 is connected to the control module 40, and an eighth node O8 is provided between the second end of the first switching tube Q1 and the first end of the second switching tube Q2; a first end of an eleventh capacitor C11 is connected to a first end of a tenth capacitor C10 and a first end of a first switch tube Q1, respectively, a second end of the eleventh capacitor C11 is connected to a first end of a twelfth capacitor C12, a second end of the twelfth capacitor C12 is connected to a second end of the tenth capacitor C10 and a second end of the second switch tube Q12, respectively, and a ninth node O9 is provided between the second end of the eleventh capacitor C11 and the first end of the twelfth capacitor C12.

A first terminal of the first coil W1 of the first transformer T1 is connected to the eighth node O8 through the fifth inductor L5, and a second terminal of the first coil W1 is connected to the ninth node O9. The first transformer T1 realizes transformation and isolation.

A first terminal of the first diode D1 is connected to a first terminal of the dc conversion circuit module 30, a second terminal of the first diode D1 is connected to a first terminal of the second diode D2, a second terminal of the second diode D2 is connected to a second terminal of the dc conversion circuit module 20, a tenth node O10 is provided between the second terminal of the first diode D1 and the first terminal of the second diode D2, and the tenth node O10 is connected to the first terminal of the second coil W2. A first terminal of the third diode D3 is connected to the first terminal of the first diode D1 and the first terminal of the dc conversion circuit module 30, respectively, a second terminal of the third diode D3 is connected to the first terminal of the fourth diode D4, a second terminal of the fourth diode D4 is connected to the second terminal of the second diode D2 and the second terminal of the dc conversion circuit module 30, respectively, an eleventh node O11 is provided between the second terminal of the third diode D3 and the first terminal of the fourth diode D4, and the eleventh node O11 is connected to the second terminal of the fourth coil W4. The first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 form a rectifying circuit.

As shown in fig. 7 or 8, the third conversion unit 21 includes a thirteenth capacitor C13, a third switch tube Q3, a fourth switch tube Q4, a fourteenth capacitor C14, and a fifteenth capacitor C15.

Wherein a first terminal of the thirteenth capacitor C13 is connected to the second terminal of the electrical unit 50, such as the power grid, the first terminal of the third switch tube Q3, and a second terminal of the thirteenth capacitor C13 is connected to the second terminal of the fourth switch tube Q4. The thirteenth capacitor C13 is used to filter the electric signal inputted from the power grid to reduce interference.

A first terminal of a third switching tube Q3 is connected to a first terminal of a thirteenth capacitor C13, a control terminal of the third switching tube Q3 is connected to the control module 40, a second terminal of the third switching tube Q3 is connected to a first terminal of a fourth switching tube Q4, a second terminal of the fourth switching tube Q4 is connected to a second terminal of the thirteenth capacitor C13, a control terminal of the fourth switching tube Q14 is connected to the control module 40, and a twelfth node O12 is provided between the second terminal of the third switching tube Q13 and the first terminal of the fourth switching tube Q14.

A first terminal of the fourteenth capacitor C14 is connected to the first terminal of the third switch transistor Q3, a second terminal of the fourteenth capacitor C14 is connected to the first terminal of the fifteenth capacitor C15, a second terminal of the fifteenth capacitor C15 is connected to the second terminal of the fourth switch transistor Q4, and a thirteenth node O13 is located between the second terminal of the fourteenth capacitor C14 and the first terminal of the fifteenth capacitor C15.

A first terminal of a third coil W3 of the second transformer T2 is connected to a twelfth node O12 through a sixth inductor L6, a second terminal of the third coil W3 is connected to a thirteenth node O15, a first terminal of a fourth coil W4 is connected to a second terminal of the second coil W2, and a second terminal of the fourth coil W4 is connected to an eleventh node O11.

Specifically, as shown in fig. 7, when the battery pack 60 is charged, during the first half cycle of power supply, for example, when the grid voltage is a positive half cycle, the control module 40 controls the third switching tube Q3 and the fourth switching tube Q4 to remain on, or, as shown in fig. 8, controls the third switching tube Q3, the fourth switching tube Q4, and the sixth switching tube Q6 to be on, and controls the fifth switching tube Q5 to be off, so as to gate the first resonant circuit module 10 and disable the second resonant circuit module 20. The grid voltage is applied to the tenth capacitor C10, the control module 40 controls the first switching tube Q1 and the second switching tube Q2 to be switched on or off at a fixed frequency and a fixed duty ratio, and the eleventh capacitor C11 and the twelfth capacitor C12 are charged or discharged, so that an alternating voltage is formed between the midpoint of the first switching tube Q1 and the second switching tube Q2, namely the eighth node O8, the midpoint of the eleventh capacitor C11 and the twelfth capacitor C12, namely the ninth node O9. After being isolated by the first transformer T1, the ac signal is provided to a rectifying circuit composed of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4, and the ac voltage is rectified to form a dc voltage, that is, a voltage provided to both ends of the sixteenth capacitor C16 of the dc conversion circuit module 30, thereby implementing ac-dc conversion.

Similarly, as shown in fig. 7, when the battery pack 60 is charged, the control module 40 controls the first switching tube Q1 and the second switching tube Q2 to remain on during a second half period of power supply, for example, when the grid voltage is a negative half period, or as shown in fig. 8, controls the first switching tube Q1, the second switching tube Q2 and the fifth switching tube Q5 to be on, controls the sixth switching tube Q6 to be off, controls the second resonant circuit module 20 to be turned on, and does not operate the first resonant circuit module 10. Specifically, the grid voltage is applied to the thirteenth capacitor C13, and the control module 40 controls the third switch tube Q3 and the fourth switch tube Q4 to be turned on or off at a fixed frequency and a fixed duty ratio, and charges or discharges the fourteenth capacitor C14 and the fifteenth capacitor C15, so that an alternating voltage is formed between a midpoint of the third switch tube Q3 and the fourth switch tube Q4, i.e., the twelfth node O12, and a midpoint of the fourteenth capacitor C14 and the fifteenth capacitor C15, i.e., the thirteenth node O13. After being isolated by the second transformer T2, the ac signal is provided to a subsequent rectifier circuit composed of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4, and the rectifier circuit rectifies the input ac voltage into a dc voltage to realize ac-dc conversion.

As shown in fig. 7 or fig. 8, the dc conversion circuit module 30 includes a sixteenth capacitor C16, a fifth diode D5, a thirteenth switch Q15, and a seventeenth capacitor C17.

A first end of the sixteenth capacitor C16 is connected to the first end of the first diode D1 and the first end of the third diode D3, respectively, and a second end of the sixteenth capacitor C16 is connected to the second end of the second diode D2 and the second end of the fourth diode D4, respectively. The sixteenth capacitor C16 is used to filter the input electrical signal.

A first end of a fifth diode D5 is connected to the first end of the battery pack 60, a second end of the fifth diode D5 is connected to the first end of a thirteenth switching tube Q13, a second end of the thirteenth switching tube Q15 is connected to the second end of a sixteenth capacitor C16 and the second end of the battery pack 60, respectively, a control end of the thirteenth switching tube Q15 is connected to the control module 40, a fourteenth node O14 is provided between the second end of the fifth diode D5 and the first end of the thirteenth switching tube Q15, and the fourteenth node Q14 is connected to the first end of the sixteenth capacitor C16 through a seventh inductor L7.

The seventeenth capacitor C17 is used for filtering the electrical signal transmitted to the battery pack 60, a first end of the seventeenth capacitor C17 is connected to the first end of the fifth diode D5 and the first end of the battery pack 60, and a second end of the seventeenth capacitor C17 is connected to the second end of the thirteenth switch tube Q13 and the second end of the battery pack 60.

The voltage of the sixteenth capacitor C16 is proportional to the absolute value of the grid voltage, and the voltage waveform output by the first resonant circuit module 10 and the second resonant circuit module 20 is the voltage wave, so that a large-capacity electrolytic capacitor is not needed for filtering, and a small-capacity capacitor, such as a film capacitor, can be selected as the sixteenth capacitor C16.

The dc conversion circuit module 30 regulates the input dc voltage to supply to the battery pack 60. Specifically, when the thirteenth switching tube Q13 is turned on, the current of the seventh inductor L7 increases, and as shown in fig. 7 or fig. 8, the current flows in a → L7 → Q13 → B; when the thirteenth switching tube Q13 is turned off, the current of the seventh inductor L7 decreases, and the current flows in a → L7 → D5 → battery pack → B as shown in fig. 7 or 8. The thirteenth switch tube Q13 is controlled by the control module 40 to switch on and off at a high frequency, so that the current waveform of the seventh inductor L7 tracks the voltage of the sixteenth capacitor C16, thereby achieving power factor correction, and the current amplitude of the eighth inductor L8 depends on the charging power.

In the embodiment of the present invention, the switching tube may be a MOS tube or a triode or other suitable switching device.

In addition, for the Part of Part 2' in fig. 1, which is an LLC topology, when the output voltage range is wide, the switching frequency deviates from the resonant frequency more, resulting in low charging efficiency. The vehicle-mounted charging system 100 of the embodiment of the invention can adjust the duty ratio of the operation of the dc conversion circuit module 30 at the rear stage through the control module 40 to control the charging power, and the adaptable battery voltage range is wider.

In summary, in the vehicle-mounted charging system 100 according to the embodiment of the present invention, the control module 40 controls the two ends of the resonant circuit to be connected in series and conducted according to the power supply cycle signal to gate the first resonant circuit module 10 or the second resonant circuit module 20, so that the signal output by the resonant circuit module to the dc conversion circuit module is a steamed bread wave, and therefore, a large-capacity electrolytic capacitor is not needed for filtering, and therefore, the system adopts a design without an electrolytic capacitor, and only a small-capacity capacitor, such as a thin-film capacitor, is needed, so that the cost and the volume of the electrolytic capacitor portion are reduced, and the reliability and the service life of the product are improved. Even if the gating circuit module 70 is arranged, the conduction loss can be reduced by controlling the series-parallel connection conduction of the switching tubes; and the first resonant circuit module 10 and the second resonant circuit module 20 multiplex the second converting unit 12, fewer circuit devices can be adopted, the cost is reduced, and a larger battery voltage range can be adapted through the adjustment of the working duty ratio of the direct current converting circuit module 30.

Based on the on-vehicle charging system of the above embodiment, a vehicle according to an embodiment of the second aspect of the invention is described below with reference to the drawings.

FIG. 9 is a block diagram of a vehicle according to one embodiment of the present invention. As shown in fig. 9, a vehicle 1000 according to an embodiment of the present invention includes a battery pack 60 and the vehicle-mounted charging system 100 according to the above embodiment, wherein the composition of the vehicle-mounted charging system 100 may refer to the description of the above embodiment, and of course, the vehicle 1000 further includes other systems such as a transmission system, a power system, a steering system, and the like, which are not listed here.

According to the vehicle 1000 of the embodiment of the invention, by adopting the vehicle-mounted charging system 100 of the above embodiment, the cost can be reduced, the reliability can be improved, and the expansion of the charging voltage range and the improvement of the charging power can be facilitated.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like 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.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An in-vehicle charging system, characterized by comprising:

the first resonant circuit module is used for converting an electric signal of a first half cycle of power supply, and comprises a first conversion unit, a first transformer and a second conversion unit, wherein the first conversion unit comprises a first switching tube and a second switching tube, a first end of the first switching tube is connected with a first end of the electric unit, a second end of the first switching tube is connected with a first end of the second switching tube, the first transformer comprises a first coil and a second coil, the first coil is connected with the first conversion unit, and a first end of the second coil is connected with the second conversion unit;

the second resonant circuit module is used for converting an electric signal of a second half period of power supply, and comprises a third conversion unit, a second transformer and the second conversion unit, wherein the third conversion unit comprises a third switching tube and a fourth switching tube, a first end of the third switching tube is connected with a second end of the electric unit, a second end of the third switching tube is connected with a first end of the fourth switching tube, a second end of the fourth switching tube is connected with a second end of the second switching tube, the second transformer comprises a third coil and a fourth coil, the third coil is connected with the third conversion unit, a first end of the fourth coil is connected with a second end of the second coil, and a second end of the fourth coil is connected with the second conversion unit;

the direct current conversion circuit module is respectively connected with the second conversion unit and the battery pack and is used for performing direct current-direct current conversion on an input electric signal;

and the control module is used for controlling the third switching tube and the fourth switching tube to be kept conductive during a first half period of power supply and controlling the first resonant circuit module according to a timing signal of the first half period of power supply, or controlling the first switching tube and the second switching tube to be kept conductive during a second half period of power supply and controlling the second resonant circuit module according to a timing signal of the second half period of power supply.

2. The vehicle-mounted charging system according to claim 1, further comprising:

the gating circuit module comprises a fifth switching tube and a sixth switching tube, wherein the first end of the fifth switching tube is connected with the first end of the electric unit, the second end of the fifth switching tube is respectively connected with the second end of the second switching tube and the second end of the fourth switching tube, the first end of the sixth switching tube is connected with the second end of the electric unit, and the second end of the sixth switching tube is respectively connected with the second end of the second switching tube and the second end of the fourth switching tube;

the control module is further configured to control the fifth switching tube to be turned off, control the sixth switching tube, the third switching tube and the fourth switching tube to be turned on, and control the first resonant circuit module according to a timing signal of the first half cycle of power supply when the first half cycle of power supply is performed; or, when the power is supplied for the second half period, the sixth switching tube is controlled to be turned off, the fifth switching tube, the first switching tube and the second switching tube are controlled to be turned on, and the second resonant circuit module is controlled according to the timing signal of the second half period of the power supply.

3. The vehicle-mounted charging system according to claim 1 or 2,

the first conversion unit further comprises a first capacitor, a second capacitor and a third capacitor, wherein a first end of the first capacitor is connected with a first end of the electric unit, a second end of the first capacitor is connected with a second end of the second switch tube, a first end of the second capacitor is connected with a first end of the first switch tube, a second end of the second capacitor is connected with a first end of the third capacitor, a second end of the third capacitor is connected with a second end of the second switch tube, a first node is arranged between the first end of the first switch tube and the second end of the second switch tube, and a second node is arranged between the second end of the second capacitor and the first end of the third capacitor;

a first end of the first coil is connected with the first node through a first inductor, and a second end of the first coil is connected with the second node;

the second conversion unit comprises a seventh switching tube, an eighth switching tube, a ninth switching tube and a tenth switching tube, wherein the first end of the seventh switching tube is connected with the first end of the dc conversion circuit module, the second end of the seventh switching tube is connected with the first end of the eighth switching tube, the control end of the seventh switching tube is connected with the control module, the second end of the eighth switching tube is connected with the second end of the dc conversion circuit module, the control end of the eighth switching tube is connected with the control module, a third node is arranged between the second end of the seventh switching tube and the first end of the eighth switching tube, the third node is connected with the first end of the second coil through a second inductor, and the first end of the ninth switching tube is connected with the first end of the seventh switching tube and the first end of the dc conversion circuit module, the second end of the ninth switching tube is connected with the first end of the tenth switching tube, the control end of the ninth switching tube is connected with the control module, the second end of the tenth switching tube is connected with the second end of the eighth switching tube and the second end of the direct current conversion circuit module, and a fourth node is arranged between the second end of the ninth switching tube and the first end of the tenth switching tube.

4. The vehicle-mounted charging system according to claim 3,

the third conversion unit further comprises a fourth capacitor, a fifth capacitor and a sixth capacitor, wherein a first end of the fourth capacitor is connected with a second end of the electric unit, a second end of the fourth capacitor is respectively connected with a second end of the second switching tube and a second end of the fourth switching tube, a first end of the fifth capacitor is connected with a first end of the third switching tube, a second end of the fifth capacitor is connected with a first end of the sixth capacitor, a second end of the sixth capacitor is connected with a second end of the fourth switching tube, a fifth node is arranged between the second end of the third switching tube and the first end of the fourth switching tube, and a sixth node is arranged between the second end of the fifth capacitor and the first end of the sixth capacitor;

the first end of the third coil is connected with the fifth node through a third inductor, the second end of the third coil is connected with the sixth node, the first end of the fourth coil is connected with the second end of the second coil through a seventh capacitor, and the second end of the fourth coil is connected with the fourth node.

5. The vehicle-mounted charging system according to claim 4, wherein the direct-current conversion circuit module includes:

a first end of the eighth capacitor is connected with a first end of the seventh switching tube and a first end of the ninth switching tube respectively, and a second end of the eighth capacitor is connected with a second end of the eighth switching tube and a second end of the tenth switching tube respectively;

a first end of the eleventh switch tube is connected with a first end of the battery pack, a second end of the eleventh switch tube is connected with a first end of the twelfth switch tube, a control end of the eleventh switch tube is connected with the control module, a second end of the twelfth switch tube is respectively connected with a second end of the eighth capacitor and a second end of the battery pack, a control end of the twelfth switch tube is connected with the control module, a seventh node is arranged between the second end of the eleventh switch tube and the first end of the twelfth switch tube, and the seventh node is connected with the first end of the eighth capacitor through a fourth inductor;

and a first end of the ninth capacitor is connected with the first end of the eleventh switch tube and the first end of the battery pack respectively, and a second end of the ninth capacitor is connected with the second end of the twelfth switch tube and the second end of the battery pack respectively.

6. The vehicle-mounted charging system according to claim 1 or 2,

the first conversion unit further comprises a tenth capacitor, an eleventh capacitor and a twelfth capacitor, wherein a first end of the tenth capacitor is connected with the first end of the electrical unit, a second end of the tenth capacitor is connected with the second end of the second switching tube, a first end of the eleventh capacitor is connected with the first end of the first switching tube, a second end of the eleventh capacitor is connected with the first end of the twelfth capacitor, a second end of the twelfth capacitor is connected with the second end of the second switching tube, an eighth node is arranged between the second end of the first switching tube and the first end of the second switching tube, and a ninth node is arranged between the second end of the eleventh capacitor and the first end of the twelfth capacitor;

the first end of the first coil is connected with the eighth node through a fifth inductor, and the second end of the first coil is connected with the ninth node;

the second conversion unit comprises a first diode, a second diode, a third diode and a fourth diode, wherein the first end of the first diode is connected with the first end of the direct current conversion circuit module, the second end of the first diode is connected with the first end of the second diode, the second end of the second diode is connected with the second end of the direct current conversion circuit module, a tenth node is arranged between the second end of the first diode and the first end of the second diode, the tenth node is connected with the first end of the second coil, the first end of the third diode is respectively connected with the first end of the first diode and the first end of the direct current conversion circuit module, the second end of the third diode is connected with the first end of the fourth diode, and the second end of the fourth diode is respectively connected with the second end of the second diode, the first end of the second diode, the second diode and the second end of the second diode, And the second end of the direct current conversion circuit module is connected, and an eleventh node is arranged between the second end of the third diode and the first end of the fourth diode.

7. The vehicle-mounted charging system according to claim 6,

the third conversion unit further comprises a thirteenth capacitor, a fourteenth capacitor and a fifteenth capacitor, wherein a first end of the thirteenth capacitor is connected to the second end of the electrical unit and the first end of the third switching tube, a second end of the thirteenth capacitor is connected to the second end of the fourth switching tube, a first end of the fourteenth capacitor is connected to the first end of the third switching tube, a second end of the fourteenth capacitor is connected to the first end of the fifteenth capacitor, a second end of the fifteenth capacitor is connected to the second end of the fourth switching tube, a twelfth node is arranged between the second end of the third switching tube and the first end of the fourth switching tube, and a thirteenth node is arranged between the second end of the fourteenth capacitor and the first end of the fifteenth capacitor;

the first end of the third coil is connected with the twelfth node through a sixth inductor, the second end of the third coil is connected with the thirteenth node, the first end of the fourth coil is connected with the second end of the second coil, and the second end of the fourth coil is connected with the eleventh node.

8. The vehicle-mounted charging system according to claim 7, wherein the direct-current conversion circuit module includes:

a sixteenth capacitor, a first end of the sixteenth capacitor is connected to the first end of the first diode and the first end of the third diode, respectively, and a second end of the sixteenth capacitor is connected to the second end of the second diode and the second end of the fourth diode, respectively;

the first end of the fifth diode is connected with the first end of the battery pack, the second end of the fifth diode is connected with the first end of the thirteenth switching tube, the second end of the thirteenth switching tube is respectively connected with the second end of the sixteenth capacitor and the second end of the battery pack, the control end of the thirteenth switching tube is connected with the control module, a fourteenth node is arranged between the second end of the fifth diode and the first end of the thirteenth switching tube, and the fourteenth node is connected with the first end of the sixteenth capacitor through a seventh inductor.

9. The vehicle charging system of claim 8, wherein the dc conversion circuit module further comprises:

and a seventeenth capacitor, wherein a first end of the seventeenth capacitor is connected with the first end of the fifth diode and the first end of the battery pack, and a second end of the seventeenth capacitor is connected with the second end of the thirteenth switching tube and the second end of the battery pack.

10. A vehicle characterized by comprising a battery pack and the on-vehicle charging system according to any one of claims 1 to 9.