12V / 48V DCDC converter for vehicle

Abstract

The invention discloses a 12V / 48V DCDC converter for a vehicle, and belongs to the technical field of automobile electric appliance control. Comprising a main DCDC loop and a uDCDC loop which are connected in parallel. The main DCDC loop is a bidirectional Buck-Boost circuit, and the main DCDC loop is a bidirectional Buck- The uDCDC loop comprises a Buck power circuit and an ORing circuit which are connected in series with each other; the Buck power circuit and the ORing circuit are connected with the positive electrode of the super capacitor module, and the negative electrode of the super capacitor module is grounded to form a pre-charging loop. The system is provided with a high-power main DCDC and a low-power uDCDC, so that a 12V battery of the whole vehicle can be omitted, meanwhile, the uDCDC is combined with the super capacitor module, the constant-current voltage limiting function is achieved, and when a 12V load end is short-circuited, the super capacitor module releases short-circuit current, fuses a short-circuit loop fuse and protects 12V main node voltage within a normal working required range.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile electrical appliance control, and in particular to a 12V / 48V DCDC converter for automobiles. Background Art

[0002] With the development of electronic and electrical technology and the higher requirements of modern automobiles for environmental protection and efficiency, in recent years, 48V power supply systems have been gradually promoted by vehicle manufacturers, especially in electric vehicles. Compared with 12V power supply systems, the current of 48V power supply systems is 1 / 4 of the original under the same power, which can greatly reduce heat loss and wiring harness costs. At the same time, it can participate in energy recovery more effectively and reduce vehicle energy consumption.

[0003] The current 48V power supply system mainly appears in the following forms:

[0004] 1. Configure a 48V system. The low-voltage system is mainly powered by 12V, and only some high-power loads are powered by 48V. Usually, a high-power high-voltage to 12V DCDC, 12V battery, 48V battery, and 12V to 48V DCDC are configured. The typical architecture is as follows: Figure 1 shown.

[0005] 2. Configure a 48V system. The low-voltage system power supply is equally important with 12V and 48V. Usually, high-voltage to 12V DCDC and high-voltage to 48V DCDC are configured, 12V battery, 48V battery, and the typical architecture is as follows: Figure 2 shown.

[0006] 3. Configure a 48V system. The low-voltage system is powered by 48V, and the original 12V common load is retained. Usually, a high-power 48V DCDC, a 48V battery, a 48V to 12V DCDC, and a 12V battery are configured. The typical architecture is as follows: Figure 3 shown.

[0007] It can be seen that although the number of 48V loads on cars is gradually increasing, and more and more high-power loads choose to use 48V power supply, the 12V system is difficult to be completely replaced due to its huge industrial chain and cost advantages. For a long time, 12V and 48V systems will coexist in the car. However, if there are both 48V and 12V batteries in the car, the cost is also increased invisibly. At the same time, in the current system, when the load is short-circuited, the main circuit voltage will drop instantly, lower than the normal working voltage range, causing undervoltage faults in other ECU controllers on the main network.

[0008] Therefore, in order to meet the requirements of future automotive low-voltage power supply systems and simplify the system as much as possible to save costs, an automotive 12V / 48V DCDC converter is urgently needed to replace the 12V power supply system. Summary of the invention

[0009] In view of the defects of the prior art, the present invention provides a vehicle-use 12V / 48V DCDC converter for converting a 48V power supply into a 12V power supply. At the same time, when a short circuit occurs at the 12V load end, the 12V main node voltage can be protected within the normal working requirement range.

[0010] In order to achieve the above object, the present invention provides a 12V / 48V DCDC converter for a vehicle, comprising:

[0011] The main DCDC loop and uDCDC loop are connected in parallel with each other;

[0012] The main DCDC loop is a bidirectional Buck-Boost circuit;

[0013] The uDCDC loop includes a Buck power circuit and an ORing circuit connected in series; the Buck power circuit and the ORing circuit are connected to the positive electrode of the supercapacitor module, and the negative electrode of the supercapacitor module is grounded to form a pre-charging loop.

[0014] Furthermore, the bidirectional Buck-Boost circuit, Buck power circuit, ORing circuit and static circuit switch are all controlled by the MCU.

[0015] Furthermore, the supercapacitor module is in the form of 1 in parallel and 5 in series, and the rated voltage is 13.5V.

[0016] Furthermore, a static circuit switch is connected in series in the main DCDC loop, which is used to close the main DCDC loop when the vehicle is powered off, and is controlled by the MCU.

[0017] The present invention also provides a vehicle low-voltage power supply system, based on the vehicle bidirectional 12V / 48V DCDC converter as described above, including a 48V DCDC converter, a bidirectional 12V / 48VDCDC converter and a 48V lithium battery;

[0018] One side of the 48V DCDC converter is connected to the positive electrode of the high-voltage component of the vehicle, and the other side is connected to the 48V lithium battery, the bidirectional 12V / 48V DCDC converter and the 48V electrical load to convert the high-voltage electric energy into 48V electric energy;

[0019] The bidirectional 12V / 48V DCDC converter converts 48V electric energy output by a 48V DCDC converter or a 48V lithium battery into 12V electric energy, and outputs it to a 12V electrical load.

[0020] Beneficial effects of the present invention:

[0021] The DCDC of the present invention comprises a high-power main DCDC and a low-power uDCDC. When the vehicle is powered on, the main DCDC supplies power to the 12V system. When the vehicle is powered off, the uDCDC supplies power to the 12V system, so that the 12V battery of the vehicle can be eliminated.

[0022] At the same time, uDCDC is combined with a supercapacitor module and has a constant current and voltage limiting function, which can charge the supercapacitor module from 0 volts to the rated voltage. When a short circuit occurs at the 12V load end, the supercapacitor module releases the short-circuit current, blows the short-circuit circuit fuse, and protects the 12V main node voltage within the normal working requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of the existing 48V power supply system (method one).

[0024] Figure 2 This is a structural diagram of the existing 48V power supply system (method two).

[0025] Figure 3 This is a structural diagram of the existing 48V power supply system (method three).

[0026] Figure 4 This is a schematic diagram of the structure of a 12V / 48V DCDC converter for a vehicle according to an embodiment of the present invention.

[0027] Figure 5 This is a structural diagram of an example 1 of a 12V / 48V DCDC converter for a vehicle according to an embodiment of the present invention.

[0028] Figure 6 The figure is a schematic diagram of the structure of the low-voltage power supply system of a whole vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further explained below in conjunction with the accompanying drawings and embodiments.

[0030] like Figure 4 As shown, an embodiment of the present invention provides a bidirectional 12V / 48V DCDC converter for a vehicle, comprising: a main DCDC circuit (high power circuit) and a uDCDC circuit (low power circuit) connected in parallel, and a super capacitor module is also carried on the uDCDC circuit. After using the DCDC, the 12V main battery can be removed from the vehicle, and the problem of bus voltage drop when the 12V load side is short-circuited can be solved.

[0031] The main DCDC loop is a bidirectional Buck-Boost circuit that can provide stable and efficient power conversion between 48V and 12V. In order to further reduce system losses, a static circuit switch can be connected in series in the main DCDC loop to close the main DCDC loop when the vehicle is powered off.

[0032] The uDCDC circuit is used to convert 48V voltage into 12V voltage. The uDCDC rated power is small. When the vehicle is powered off, most of the ECUs on the vehicle enter the sleep mode, and the required power consumption is low. If the main DCDC is allowed to maintain operation, it often cannot operate in the DCDC high efficiency area. The uDCDC circuit includes a Buck power circuit and an ORing circuit connected in series. The positive electrode of the supercapacitor module is connected between the Buck power circuit and the ORing circuit, and the negative electrode of the supercapacitor module is grounded to form a pre-charge circuit. Among them, the ORing circuit can reduce energy loss and provide comprehensive protection functions. It has the advantages of low power consumption, high current carrying capacity, reverse polarity protection, reverse current blocking and load dump protection. The ORing circuit can quickly detect the voltage difference between the power supply and the load, and respond quickly when the voltage difference drops to the set threshold, limiting the duration and size of the reverse current. The supercapacitor module is typically configured as 1 in parallel and 5 in series, with a rated voltage of 13.5V. The supercapacitor has a small internal resistance, large charging and discharging power, a wide operating temperature range, and a long life, making it very suitable for use as a backup power supply. Its maximum discharge current exceeds 1000A, which can well provide the required power for transient high-power loads and support the voltage of the vehicle power supply network within the required range. On the 12V side, when a branch short-circuit occurs, the supercapacitor can provide transient high current and keep the voltage on the main line greater than the minimum required voltage for the load ECU to work before the branch fuse blows.

[0033] The bidirectional Buck-Boost circuit, Buck power circuit, ORing circuit and static circuit switch are all controlled by the MCU.

[0034] The specific working process of the bidirectional 12V / 48V DCDC converter is as follows: when the vehicle is powered on, the main DCDC circuit supplies power to the 12V electrical load, and can reversely absorb the energy feedback from the 12V end; when the vehicle is powered off, the uDCDC circuit supplies power to the 12V electrical load. The uDCDC circuit has a constant current and voltage limiting function, and can charge the supercapacitor module from 0 volts to the rated voltage. When a short circuit occurs at the 12V load end, the supercapacitor module on the low-power circuit releases the short-circuit current, blows the short-circuit circuit fuse, and protects the 12V main node voltage within the required range.

[0035] In the embodiment of the present invention, the bidirectional Buck-Boost circuit and the Buck power circuit are not specifically limited. The current general circuits can be configured in the 12V / 48V DCDC converter. One of the schematic diagrams is shown in FIG. Figure 5 shown.

[0036] like Figure 6As shown, an embodiment of the present invention further provides a vehicle low-voltage power supply system, including a 48V DCDC converter, a bidirectional 12V / 48V DCDC converter and a 48V lithium battery.

[0037] One side of the 48V DCDC converter is connected to the positive pole of the high-voltage components of the vehicle, and the other side is connected to the 48V lithium battery, the bidirectional 12V / 48V DCDC converter and the 48V electrical load, converting the high-voltage electrical energy into 48V electrical energy and outputting it to the 48V lithium battery, the bidirectional 12V / 48V DCDC converter and the 48V electrical load; the bidirectional 12V / 48V DCDC converter converts the 48V electrical energy output by the 48V DCDC converter or the 48V lithium battery into 12V electrical energy, and outputs it to the 12V electrical load. The system can complete the power supply of the 48V electrical load and 12V electrical load of the whole vehicle.

[0038] Among them, 48V DCDC is any current converter that supports converting high voltage power into 48V power.

[0039] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to these embodiments without departing from the present invention and its essence. Therefore, the scope of protection of the present invention is limited by the appended claims.

Claims

1. A bidirectional 12V / 48V DCDC converter for a vehicle, characterized in that: include: The main DCDC loop and uDCDC loop are connected in parallel with each other; The main DCDC loop is a bidirectional Buck-Boost circuit; The uDCDC loop includes a Buck power circuit and an ORing circuit connected in series; the Buck power circuit and the ORing circuit are connected to the positive electrode of the supercapacitor module, and the negative electrode of the supercapacitor module is grounded to form a pre-charging loop.

2. The vehicle bidirectional 12V / 48V DCDC converter according to claim 1, characterized in that: The bidirectional Buck-Boost circuit, Buck power circuit, ORing circuit and static circuit switch are all controlled by MCU.

3. The vehicle bidirectional 12V / 48V DCDC converter according to claim 1, characterized in that: The supercapacitor module adopts the form of 1 in parallel and 5 in series, and the rated voltage is 13.5V.

4. The vehicle bidirectional 12V / 48V DCDC converter according to claim 1, characterized in that: A static circuit switch is also connected in series in the main DCDC loop, which is used to close the main DCDC loop when the vehicle is powered off and is controlled by the MCU.

5. A vehicle low-voltage power supply system, based on the vehicle bidirectional 12V / 48V DCDC converter according to any one of claims 1 to 4, characterized in that: Including 48V DCDC converter, bidirectional 12V / 48V DCDC converter and 48V lithium battery; One side of the 48V DCDC converter is connected to the positive electrode of the high-voltage component of the vehicle, and the other side is connected to the 48V lithium battery, the bidirectional 12V / 48V DCDC converter and the 48V electrical load to convert the high-voltage electric energy into 48V electric energy; The bidirectional 12V / 48V DCDC converter converts 48V electric energy output by a 48V DCDC converter or a 48V lithium battery into 12V electric energy, and outputs it to a 12V electrical load.

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