Vehicle low-voltage power supply system and vehicle

Abstract

The utility model discloses a vehicle low-voltage power supply system and a vehicle, the vehicle low-voltage power supply system comprises a vehicle-mounted charger, a switch circuit and a first DCDC conversion circuit, the vehicle-mounted charger comprises a PFC circuit and a second DCDC conversion circuit, and the PFC circuit comprises a PFC inductor and a rectification circuit; wherein when the switching circuit is in the first state, the alternating current power supply charges the high-voltage power battery through the vehicle-mounted charger; and when the switching circuit is in a second state, the high-voltage power battery supplies power to the low-voltage battery sequentially through the second DCDC conversion circuit, the rectifying circuit and the first DCDC conversion circuit. According to the system provided by the utility model, under the condition that the high-low voltage conversion DCDC driver is damaged, the vehicle-mounted charger is temporarily called and combined with the first DCDC conversion circuit, so that the low-voltage power supply function can be recovered, and the safety of the vehicle is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicles, and in particular to a vehicle low-voltage power supply system and a vehicle. Background Art

[0002] The high-voltage system of new energy electric vehicles consists of a variety of high-voltage components, including the electric drive, onboard charger, direct current to direct current (DCDC) converter, electric air conditioner, heater, and power battery pack. In various usage scenarios, failure of a high-voltage component can often lead to reduced comfort and performance, loss of functionality, and even safety incidents. Therefore, it is necessary to address the failure degradation of high-voltage components to achieve high availability of vehicle functionality and performance, ultimately achieving safety objectives.

[0003] In related technologies, since the high-to-low voltage conversion DCDC works for a long time in scenarios such as parking and driving, it is often prone to failure, resulting in the loss of low-voltage power supply function and the inability of the car to drive normally, affecting the safety of the vehicle. Utility Model Content

[0004] The present invention aims to at least partially resolve one of the technical problems in the related art. To this end, the first object of the present invention is to provide a vehicle low-voltage power supply system. In the event of a damage to the high-to-low voltage conversion DCDC driver, the low-voltage power supply function can be restored by temporarily activating an onboard charger and combining it with a first DCDC conversion circuit, thereby ensuring vehicle safety. In the event of a normal high-to-low voltage conversion DCDC driver, the vehicle can be driven in a driving scenario by activating the onboard charger and combining it with the first DCDC conversion circuit to form a high-to-low voltage conversion backup DCDC, thereby providing a dual DCDC power supply and improving the reliability and efficiency of the low-voltage power supply.

[0005] The second object of the present invention is to provide a vehicle.

[0006] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a vehicle low-voltage power supply system, comprising: an on-board charger, a switching circuit, and a first DCDC conversion circuit, wherein the on-board charger includes a PFC (Power Factor Correction Circuit) circuit and a second DCDC conversion circuit, the PFC circuit includes a PFC inductor and a rectifier circuit, and one end of the PFC inductor is suitable for connecting to an AC power supply; the switching circuit is respectively connected to the other end of the PFC inductor, the rectifier circuit, and the first DCDC conversion circuit, and the first DCDC conversion circuit is also connected to a low-voltage battery; the second DCDC conversion circuit is respectively connected to the rectifier circuit and a high-voltage power battery; wherein, when the switching circuit is in a first state, the AC power supply charges the high-voltage power battery through the on-board charger; when the switching circuit is in a second state, the high-voltage power battery supplies power to the low-voltage battery through the second DCDC conversion circuit, the rectifier circuit, and the first DCDC conversion circuit in sequence.

[0007] According to the vehicle low-voltage power supply system of the present utility model, when the switch circuit is in the first state, the AC power supply charges the high-voltage power battery through the on-board charger. When the switch circuit is in the second state, the high-voltage power battery supplies power to the low-voltage battery through the second DCDC conversion circuit, the rectifier circuit, and the first DCDC conversion circuit. As a result, if the high-low voltage conversion DCDC driver is damaged, the system can restore the low-voltage power supply function by temporarily using the on-board charger and combining it with the first DCDC conversion circuit, thereby ensuring vehicle safety. If the vehicle's high-low voltage conversion DCDC driver is normal, the on-board charger can be used in driving scenarios by combining it with the first DCDC conversion circuit to form a high-low voltage conversion backup DCDC, thereby creating a dual DCDC power supply, improving the reliability and efficiency of the low-voltage power supply.

[0008] In addition, the vehicle low-voltage power supply system according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present utility model, the rectifier circuit includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube. The first end of the first switching tube is connected to the second end of the second switching tube and is connected to the switching circuit as the first end of the PFC circuit. The first end of the third switching tube is connected to the second end of the fourth switching tube and is connected to the switching circuit as the second end of the PFC circuit. The second end of the first switching tube is connected to the second end of the third switching tube and is connected to the second DC-DC converter circuit as the third end of the PFC circuit. The first end of the second switching tube is connected to the first end of the fourth switching tube and is connected to the second DC-DC converter circuit as the fourth end of the PFC circuit.

[0010] According to one embodiment of the present utility model, the switching circuit includes a first switch, a second switch, a third switch and a fourth switch, one end of the first switch is connected to the other end of the PFC inductor, the other end of the first switch is connected to the first end of the rectifier circuit, one end of the second switch is suitable for connecting to the AC power supply, the other end of the second switch is connected to the second end of the rectifier circuit, one end of the third switch is connected to the other end of the first switch, the other end of the third switch is connected to the first end of the first DCDC converter circuit, one end of the fourth switch is connected to the other end of the second switch, and the other end of the fourth switch is connected to the second end of the first DCDC converter circuit.

[0011] According to one embodiment of the present utility model, the first DCDC conversion circuit includes: a first inductor, one end of the first inductor is connected to the other end of the third switch; a first capacitor, one end of the first capacitor is connected to the other end of the fourth switch; a first transformer, one end of the primary winding of the first transformer is connected to the other end of the first inductor, and the other end of the primary winding of the first transformer is connected to the other end of the first capacitor; a first diode and a second diode, the cathode of the first diode is connected to one end of the secondary winding of the first transformer, the cathode of the second diode is connected to the other end of the secondary winding of the first transformer, the anode of the first diode and the anode of the second diode are both connected to the negative pole of the low-voltage battery, and the center tap of the secondary winding of the first transformer is connected to the positive pole of the low-voltage battery.

[0012] According to one embodiment of the present invention, the first DCDC conversion circuit further includes: a second capacitor, one end of the second capacitor is connected to the center tap of the secondary winding of the first transformer, and the other end of the second capacitor is connected to the anode of the first diode and the anode of the second diode.

[0013] According to an embodiment of the present invention, the PFC circuit further includes: a third capacitor, one end of the third capacitor is connected to the third end of the rectifier circuit, and the other end of the third capacitor is connected to the fourth end of the rectifier circuit.

[0014] According to one embodiment of the present invention, the second DCDC conversion circuit is an LLC (Inductor-Inductor-Capacitor) resonant circuit or a CLLC (Capacitor-Inductor-Capacitor-Inductor) resonant circuit.

[0015] According to one embodiment of the present utility model, the above-mentioned system further includes: a third DCDC conversion circuit, wherein the third DCDC conversion circuit is connected to the high-voltage power battery and the low-voltage battery respectively, wherein when the switching circuit is in the third state, the high-voltage power battery supplies power to the low-voltage battery through the third DCDC conversion circuit.

[0016] According to one embodiment of the present invention, the third DCDC conversion circuit is an LLC resonant circuit or a CLLC resonant circuit.

[0017] To achieve the above-mentioned objectives, a second embodiment of the present invention provides a vehicle, comprising the above-mentioned vehicle low-voltage power supply system.

[0018] According to the vehicle of the embodiment of the present utility model, through the above-mentioned vehicle low-voltage power supply system, when the high-low voltage conversion DCDC driver is damaged, the low-voltage power supply function can be restored by temporarily calling the on-board charger and combining it with the first DCDC conversion circuit, thereby ensuring the safety of the vehicle; when the high-low voltage conversion DCDC driver of the vehicle is normal, in the driving scenario, the on-board charger is called and combined with the first DCDC conversion circuit to form a high-low voltage conversion backup DCDC, which can form a dual DCDC power supply, thereby improving the reliability and power of the low-voltage power supply.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a block diagram of a low-voltage power supply system for a vehicle according to an embodiment of the present invention;

[0021] Figure 2 1 is a topological diagram of a low-voltage power supply system for a vehicle according to an embodiment of the present invention;

[0022] Figure 3 1 is a block diagram of a low-voltage power supply system for a vehicle according to an embodiment of the present invention;

[0023] Figure 4 It is a block diagram of a vehicle according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0024] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] The vehicle low-voltage power supply system and the vehicle proposed in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0026] Figure 1 Schematic diagram of a low-voltage power supply system for a vehicle according to an embodiment of the present invention.

[0027] like Figure 1 As shown, a low-voltage power supply system 1000 for a vehicle according to an embodiment of the present invention includes: an on-board charger 100, a switching circuit 200, and a first DC-DC converter circuit 300. The on-board charger 100 includes a PFC circuit 110 and a second DC-DC converter circuit 120. The PFC circuit 110 includes a PFC inductor L and a rectifier circuit 111. One end of the PFC inductor L is suitable for connecting to an AC power source. The switching circuit 200 is respectively connected to the other end of the PFC inductor L, the rectifier circuit 111, and the first DC-DC converter circuit 300. The first DC-DC converter circuit 300 is also connected to a low-voltage battery. The second DC-DC converter circuit 120 is respectively connected to the rectifier circuit 111 and the high-voltage power battery. When the switching circuit 200 is in a first state, the AC power source charges the high-voltage power battery through the on-board charger 100. When the switching circuit 200 is in a second state, the high-voltage power battery supplies power to the low-voltage battery through the second DC-DC converter circuit 120, the rectifier circuit 111, and the first DC-DC converter circuit 300.

[0028] Specifically, when the power battery is charging, the switching circuit 200 is in the first state, the AC power supply is connected to the rectifier circuit 111 through the PFC inductor L, and the rectifier circuit 111 is not connected to the first DCDC conversion circuit 300. The rectifier circuit 111 can convert the voltage provided by the AC power supply into a DC voltage and improve the power factor through the PFC inductor L to provide a stable DC power supply for the subsequent second DCDC conversion circuit 120. The second DCDC conversion circuit 120 can convert the DC voltage output by the rectifier circuit 111 into a voltage and current level suitable for charging the power battery to charge the power battery.

[0029] When the vehicle's high-to-low voltage DC / DC converter fails, the switch circuit 200 enters the second state. The rectifier circuit 111 connects to the first DC / DC converter circuit 300 and disconnects from the PFC inductor L. The power battery outputs DC power to the second DC / DC converter circuit 120. The second DC / DC converter circuit 120 converts the DC power provided by the power battery into DC power with voltage and current levels suitable for the operation of the rectifier circuit 111 and outputs it to the rectifier circuit 111. The rectifier circuit 111 operates in a PWM (Pulse Width Modulation) mode to drive the first DC / DC converter circuit 300. The first DC / DC converter circuit 300 converts the power provided by the rectifier circuit 111 into a voltage suitable for powering the low-voltage battery and outputs it to the low-voltage battery. Therefore, if the high-to-low voltage DC / DC converter fails, the low-voltage power supply function can be restored by temporarily using the onboard charger 100 in conjunction with the first DC / CDC converter circuit 300.

[0030] When the vehicle's high- and low-voltage conversion DCDC driver is normal, in a driving scenario, by calling the on-board charger 100 and combining it with the first DCDC conversion circuit 300 to form a high- and low-voltage conversion backup DCDC, a dual DCDC power supply can be formed, thereby improving the reliability and power of the low-voltage power supply.

[0031] According to one embodiment of the present invention, Figure 2As shown, the rectifier circuit 111 includes a first switching transistor M1, a second switching transistor M2, a third switching transistor M3, and a fourth switching transistor M4. The first end of the first switching transistor M1 is connected to the second end of the second switching transistor M2 and is connected to the switching circuit 200 as the first end of the PFC circuit 110. The first end of the third switching transistor M3 is connected to the second end of the fourth switching transistor M4 and is connected to the switching circuit 200 as the second end of the PFC circuit 110. The second end of the first switching transistor M1 is connected to the second end of the third switching transistor M3 and is connected to the second DC-DC converter circuit 120 as the third end of the PFC circuit 110. The first end of the second switching transistor M2 is connected to the first end of the fourth switching transistor M4 and is connected to the second DC-DC converter circuit 120 as the fourth end of the PFC circuit 110.

[0032] Specifically, if Figure 2 As shown, the second DCDC conversion circuit 120 includes a primary switching circuit 200, a voltage conversion circuit and a secondary switching circuit 200. The primary switching circuit 200 is respectively connected to the rectifier circuit 111 and the primary side of the voltage conversion circuit, and the secondary switching circuit 200 is respectively connected to the secondary side of the voltage conversion circuit and the power battery. The primary switching circuit 200 includes switching transistors M7, M8, M9, and M10; the secondary switching circuit 200 includes switching transistors M11, M12, M13, and M14; and the voltage conversion circuit includes: a first resonant inductor L2, a first resonant capacitor C4, a second transformer T2, a second resonant inductor L3, and a second resonant capacitor C5. The first resonant inductor L2 is connected in series between the first output terminal of the primary switching circuit 200 and one end of the primary winding of the second transformer T2; the first resonant capacitor C4 is connected in series between the second output terminal of the primary switching circuit 200 and the other end of the primary winding of the second transformer T2; the second resonant inductor L3 is connected in series between the first input terminal of the secondary switching circuit 200 and one end of the secondary winding of the second transformer T2; and the second resonant capacitor C5 is connected in series between the second input terminal of the secondary switching circuit 200 and one end of the secondary winding of the second transformer T2.

[0033] According to one embodiment of the present invention, Figure 2 As shown, the switching circuit 200 includes a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4. One end of the first switch S1 is connected to the other end of the PFC inductor L, and the other end of the first switch S1 is connected to the first end of the rectifier circuit 111. One end of the second switch S2 is suitable for connecting to an AC power supply, and the other end of the second switch S2 is connected to the second end of the rectifier circuit 111. One end of the third switch S3 is connected to the other end of the first switch S1, and the other end of the third switch S3 is connected to the first end of the first DCDC converter circuit 300. One end of the fourth switch S4 is connected to the other end of the second switch S2, and the other end of the fourth switch S4 is connected to the second end of the first DCDC converter circuit 300.

[0034] Specifically, when the power battery is charged, the switch circuit 200 is in the first state, the first switch S1 and the second switch S2 are closed, the third switch S3 and the fourth switch S4 are open, the AC power supply is connected to the rectifier circuit 111 through the PFC inductor L, and the rectifier circuit 111 is not connected to the first DCDC conversion circuit 300. The first switch tube M1, the second switch tube M2, the third switch tube M3 and the fourth switch tube M4 in the rectifier circuit 111 can perform ACDC conversion on the voltage provided by the AC power supply, and convert the input AC power into DC power. The power factor is improved through the PFC inductor L, and DC power is output to the second DCDC conversion circuit. The input and output currents are regulated by adjusting the switching frequency of the switching tubes M7-M10 of the primary switching circuit 200. The electric energy is transmitted to the secondary switching circuit 200 through the first resonant inductor L2, the first resonant capacitor C4, the second transformer T2, the second resonant inductor L3 and the second resonant capacitor C5. The switching tubes M11-M14 of the secondary switching circuit 200 are output rectifier tubes, which perform rectification and filter the current through the capacitor C6 to charge the power battery.

[0035] When the high-low voltage conversion DCDC driver of the vehicle fails, the switch circuit 200 is in the second state, the third switch S3 and the fourth switch S4 are closed, the first switch S1 and the second switch S2 are disconnected, the rectifier circuit 111 is connected to the first DCDC conversion circuit 300, and is disconnected from the PFC inductor L. The power battery outputs DC power to the second DCDC conversion circuit 120, and the output current is regulated by adjusting the switching frequency of the switch tubes M11-M14 of the secondary side switch circuit 200. The second resonant inductor L3, the second resonant capacitor C5, the second transformer T2, the first resonant inductor L2 and the first resonant capacitor C6 are connected. C4 transfers the electrical energy to the primary switching circuit 200. The switching tubes M7-M10 of the primary switching circuit 200 act as rectifier output tubes to perform rectification, converting the electrical energy into direct current with voltage and current levels suitable for the operation of the rectifier circuit 111 and outputting it to the rectifier circuit 111. The first switching tube M1, the second switching tube M2, the third switching tube M3, and the fourth switching tube M4 in the rectifier circuit 111 operate in a PWM state to drive the first DCDC conversion circuit 300. The first DCDC conversion circuit 300 converts the electrical energy provided by the rectifier circuit 111 into a voltage suitable for powering the low-voltage battery, and outputs it to the low-voltage battery to power the low-voltage battery.

[0036] According to one embodiment of the present invention, Figure 2As shown, the first DCDC conversion circuit 300 includes: a first inductor L1, a first capacitor C1, a first transformer T1, a first diode D1 and a second diode D2, one end of the first inductor L1 is connected to the other end of the third switch S3; one end of the first capacitor C1 is connected to the other end of the fourth switch S4; one end of the primary winding of the first transformer T1 is connected to the other end of the first inductor L1, and the other end of the primary winding of the first transformer T1 is connected to the other end of the first capacitor C1; the cathode of the first diode D1 is connected to one end of the secondary winding of the first transformer T1, the cathode of the second diode D2 is connected to the other end of the secondary winding of the first transformer T1, the anode of the first diode D1 and the anode of the second diode D2 are both connected to the negative electrode of the low-voltage battery, and the center tap of the secondary winding of the first transformer T1 is connected to the positive electrode of the low-voltage battery.

[0037] According to one embodiment of the present invention, Figure 2 As shown, the first DCDC conversion circuit 300 further includes: a second capacitor C2, one end of the second capacitor C2 is connected to the center tap of the secondary winding of the first transformer T1, and the other end of the second capacitor C2 is connected to the anode of the first diode D1 and the anode of the second diode D2.

[0038] Specifically, when the vehicle's high-low voltage conversion DCDC driver fails, the switch circuit 200 is in the second state, the third switch S3 and the fourth switch S4 are closed, the first switch S1 and the second switch S2 are disconnected, the rectifier circuit 111 is connected to the first DCDC conversion circuit 300, and disconnected from the PFC inductor L, the power battery outputs DC power to the second DCDC conversion circuit 120, and the output current is regulated by adjusting the switching frequency of the switch tubes M11-M14 of the secondary side switch circuit 200. The electric energy is transferred to the primary side switch circuit 200 through the second resonant inductor L3, the second resonant capacitor C5, the second transformer T2, the first resonant inductor L2 and the first resonant capacitor C4. The switch tubes M7-M10 of the side switch circuit 200 act as rectifier output tubes for rectification, converting the DC power into a voltage and current level suitable for the operation of the rectifier circuit 111 and outputting it to the rectifier circuit 111. The first switch tube M1, the second switch tube M2, the third switch tube M3 and the fourth switch tube M4 in the rectifier circuit 111 operate in the PWM state to drive the first transformer T1, transforming and reducing the voltage provided by the rectifier circuit 111, and performing reverse voltage protection and synchronous rectification through the first diode D1 and the second diode D2, converting it into a voltage suitable for powering the low-voltage battery, and then filtering it through the second capacitor C2 to remove the noise in the voltage before outputting it to the low-voltage battery to power the low-voltage battery.

[0039] According to one embodiment of the present invention, Figure 2As shown, the PFC circuit 110 further includes: a third capacitor C3 , one end of the third capacitor C3 is connected to the third end of the rectifier circuit 111 , and the other end of the third capacitor C3 is connected to the fourth end of the rectifier circuit 111 .

[0040] Specifically, the third capacitor C3 can smooth the rectified pulsed DC voltage, reduce voltage fluctuation and ripple, provide a stable DC voltage for the second DCDC conversion circuit 120, and reduce the harmonic components in the current and the reactive power, thereby improving the power factor of the PFC circuit 110.

[0041] According to an embodiment of the present invention, the second DCDC conversion circuit 120 is an LLC resonant circuit or a CLLC resonant circuit. Figure 2 The second DCDC conversion circuit 120 in the CLLC resonant circuit. It should be understood that replacing the CLLC resonant circuit in 2 with an LLC resonant circuit can also achieve Figure 2 The functions that can be achieved by the second DCDC conversion circuit 120 in FIG.

[0042] According to one embodiment of the present invention, Figure 3 As shown, the above-mentioned system 1000 further includes: a third DCDC conversion circuit 400, which is connected to the high-voltage power battery and the low-voltage battery respectively. When the switch circuit 200 is in the third state, the high-voltage power battery supplies power to the low-voltage battery through the third DCDC conversion circuit 400.

[0043] Specifically, when there is no abnormality in the vehicle's high-low voltage conversion DCDC driver (i.e., the third DCDC conversion circuit 400), the switching circuit 200 is in the third state, the rectifier circuit 111 is not connected to the first DCDC conversion circuit 300, and is disconnected from the PFC inductor L. The high-voltage power battery outputs high-voltage direct current to the third DCDC conversion circuit 400. The third DCDC conversion circuit 400 can convert the high-voltage direct current into a voltage and current level suitable for charging the power battery to charge the power battery.

[0044] According to one embodiment of the present invention, the third DCDC conversion circuit 400 is an LLC resonant circuit or a CLLC resonant circuit. The structure and working principle of the third DCDC conversion circuit 400 are the same as those of the second DCDC conversion circuit 120. The specific structure and working principle of the third DCDC conversion circuit 400 can be referred to. Figure 2 The description of the specific structure and working principle of the second DCDC conversion circuit 120 in the corresponding embodiment will not be repeated here.

[0045] In summary, according to the vehicle low-voltage power supply system of the embodiment of the utility model, when the switch circuit is in the first state, the AC power supply charges the high-voltage power battery through the on-board charger; when the switch circuit is in the second state, the high-voltage power battery supplies power to the low-voltage battery through the second DCDC conversion circuit, the rectifier circuit, and the first DCDC conversion circuit. As a result, if the high-low voltage conversion DCDC driver is damaged, the system can restore the low-voltage power supply function by temporarily calling the on-board charger and combining it with the first DCDC conversion circuit, thereby ensuring the safety of the vehicle. If the vehicle's high-low voltage conversion DCDC driver is normal, in driving scenarios, the on-board charger is called and combined with the first DCDC conversion circuit to form a high-low voltage conversion backup DCDC, which can form a dual DCDC power supply, improving the reliability and efficiency of the low-voltage power supply.

[0046] Corresponding to the above embodiment, the present utility model also provides a vehicle.

[0047] Figure 4 It is a block diagram of a vehicle according to an embodiment of the present utility model.

[0048] like Figure 4 As shown, the vehicle 200 according to the embodiment of the present invention includes the above-mentioned vehicle low-voltage power supply system 100 .

[0049] According to the vehicle of the embodiment of the present utility model, through the above-mentioned vehicle low-voltage power supply system, when the high-low voltage conversion DCDC driver is damaged, the low-voltage power supply function can be restored by temporarily calling the on-board charger and combining it with the first DCDC conversion circuit, thereby ensuring the safety of the vehicle; when the high-low voltage conversion DCDC driver of the vehicle is normal, in the driving scenario, the on-board charger is called and combined with the first DCDC conversion circuit to form a high-low voltage conversion backup DCDC, which can form a dual DCDC power supply, thereby improving the reliability and power of the low-voltage power supply.

[0050] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0051] It should be understood that the various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0052] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0054] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0055] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A vehicle low-voltage power supply system, characterized in that: include: An on-board charger, a switching circuit and a first DCDC conversion circuit, wherein the on-board charger includes a PFC circuit and a second DCDC conversion circuit. The PFC circuit includes a PFC inductor and a rectifier circuit, and one end of the PFC inductor is suitable for connecting to an AC power supply; The switching circuit is respectively connected to the other end of the PFC inductor, the rectifier circuit and the first DCDC conversion circuit, and the first DCDC conversion circuit is also connected to a low-voltage battery; The second DCDC conversion circuit is connected to the rectifier circuit and the high-voltage power battery; Specifically, when the switching circuit is in a first state, the AC power supply charges the high-voltage power battery through the on-board charger; when the switching circuit is in a second state, the high-voltage power battery supplies power to the low-voltage battery through the second DCDC conversion circuit, the rectifier circuit, and the first DCDC conversion circuit in sequence.

2. The system according to claim 1, wherein: The rectifier circuit includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube. The first end of the first switching tube is connected to the second end of the second switching tube and is connected to the switching circuit as the first end of the PFC circuit. The first end of the third switching tube is connected to the second end of the fourth switching tube and is connected to the switching circuit as the second end of the PFC circuit. The second end of the first switching tube is connected to the second end of the third switching tube and is connected to the second DC-DC converter circuit as the third end of the PFC circuit. The first end of the second switching tube is connected to the first end of the fourth switching tube and is connected to the second DC-DC converter circuit as the fourth end of the PFC circuit.

3. The system according to claim 2, characterized in that The switching circuit includes a first switch, a second switch, a third switch, and a fourth switch. One end of the first switch is connected to the other end of the PFC inductor, and the other end of the first switch is connected to the first end of the rectifier circuit. One end of the second switch is suitable for connecting to the AC power supply, and the other end of the second switch is connected to the second end of the rectifier circuit. One end of the third switch is connected to the other end of the first switch, and the other end of the third switch is connected to the first end of the first DCDC converter circuit. One end of the fourth switch is connected to the other end of the second switch, and the other end of the fourth switch is connected to the second end of the first DCDC converter circuit.

4. The system according to claim 3, characterized in that The first DCDC conversion circuit includes: a first inductor, one end of the first inductor being connected to the other end of the third switch; a first capacitor, one end of the first capacitor being connected to the other end of the fourth switch; a first transformer, wherein one end of a primary winding of the first transformer is connected to the other end of the first inductor, and the other end of the primary winding of the first transformer is connected to the other end of the first capacitor; a first diode and a second diode, the cathode of the first diode is connected to one end of the secondary winding of the first transformer, the cathode of the second diode is connected to the other end of the secondary winding of the first transformer, the anode of the first diode and the anode of the second diode are both connected to the negative electrode of the low-voltage battery, and the center tap of the secondary winding of the first transformer is connected to the positive electrode of the low-voltage battery.

5. The system according to claim 4, characterized in that The first DCDC conversion circuit further includes: A second capacitor, one end of the second capacitor is connected to the center tap of the secondary winding of the first transformer, and the other end of the second capacitor is connected to the anode of the first diode and the anode of the second diode.

6. The system according to claim 2, wherein: The PFC circuit further includes: A third capacitor, one end of the third capacitor is connected to the third end of the rectifier circuit, and the other end of the third capacitor is connected to the fourth end of the rectifier circuit.

7. The system according to claim 1, wherein: The second DCDC conversion circuit is an LLC resonant circuit or a CLLC resonant circuit.

8. The system according to any one of claims 1 to 7, characterized in that: Also includes: a third DCDC conversion circuit, wherein the third DCDC conversion circuit is connected to the high-voltage power battery and the low-voltage battery respectively, wherein when the switch circuit is in the third state, the high-voltage power battery supplies power to the low-voltage battery through the third DCDC conversion circuit.

9. The system according to claim 8, characterized in that The third DCDC conversion circuit is an LLC resonant circuit or a CLLC resonant circuit.

10. A vehicle, characterized in that: The vehicle low-voltage power supply system comprises the vehicle low-voltage power supply system according to any one of claims 1-9.

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