Conversion power supply control method of vehicle-mounted direct current converter and automobile

Abstract

The invention discloses a conversion power supply control method of a vehicle-mounted direct current converter and an automobile. The method comprises the steps that a low-voltage storage battery supplies power to a vehicle-mounted low-voltage load; the vehicle-mounted direct-current converter is used for converting the power battery and then charging the low-voltage storage battery; after the vehicle is started, the electric quantity of a low-voltage storage battery and the power needed by a low-voltage load are collected in real time; the working state of the vehicle-mounted direct-current converter is controlled based on a circuit of a low-voltage storage battery and power required by a low-voltage load, and the low-voltage storage battery is adopted to provide required power consumption for the vehicle-mounted low-voltage load. Low-voltage power supply is carried out through the direct-current storage battery, meanwhile, the high efficiency of low-voltage power supply is improved by controlling the working time of the vehicle-mounted converter, and energy loss in the power supply process is reduced.

Description

Technical Field

[0001] The invention relates to the field of automobile low-voltage power supply control, and in particular to a conversion control method of an efficient on-board direct current converter and an automobile. Background Art

[0002] With the popularity of electric vehicles, their market share is getting higher and higher, and car companies are also starting to accelerate the speed of replacing electric vehicles. The energy form of electric vehicle power systems relies on power battery output. There are technical pain points in the endurance and efficiency of electric vehicles on the market. The higher the working efficiency of the high-voltage system means lower energy consumption and longer driving range. In order to improve the working efficiency of the high-voltage system, higher requirements and challenges are put forward for technical personnel.

[0003] Among them, DCDC conversion efficiency generally has the characteristics of low conversion efficiency in low power output range and high conversion efficiency in high power output range. The physical characteristics of its low power working range often trouble technical personnel.

[0004] The DCDC direct current converter control method of the prior art: the output power of the DCDC is determined by the power consumption of the low-voltage load. The DCDC converts the power battery output to power the low-voltage electrical appliances, and adopts a power following strategy. When the vehicle is only idling or slow charging, and there are no high-power loads such as fans and water pumps, the DCDC output power is in a low-power range and has low efficiency. As the power consumption of the low-voltage load increases, its output power increases accordingly, and the power supply control leads to low efficiency. Summary of the invention

[0005] The object of the present invention is to overcome the deficiencies of the prior art and to provide a conversion control method for a vehicle-mounted DC converter and a vehicle, which provide low-voltage power supply through a DC battery and improve the efficiency of the low-voltage power supply by controlling the working timing of the vehicle-mounted converter to reduce energy loss during the power supply process.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a conversion power supply control method of an on-board DC converter, a low-voltage battery supplies power to an on-board low-voltage load; the on-board DC converter is used to convert the power battery to charge the low-voltage battery; after the vehicle is started, the power of the low-voltage battery and the power required by the low-voltage load are collected in real time; based on the circuit of the low-voltage battery and the power required by the low-voltage load, the working state of the on-board DC converter is controlled, and the low-voltage battery is used to provide the required power consumption for the on-board low-voltage load.

[0007] When it is detected that the power of the low-voltage battery is in a high power state, the output power of the low-voltage battery is between 0 and the threshold P1 to supply power to the low-voltage load; the output power of the low-voltage battery is determined based on the size of the low-voltage load; at this time, the DCDC is controlled to be in a high-voltage standby state.

[0008] The high power state of the low-voltage battery is determined by real-time monitoring of the SOC value of the low-voltage battery, presetting the corresponding SOC interval under the high power state, and determining that the battery is in a high power state when the real-time collected SOC value is within the SOC interval.

[0009] When it is detected that the power of the low-voltage battery is lower than the lower limit of the SOC range, the vehicle controller VCU obtains the real-time SOC value through the power sensor, and the VCU sends a control command to the on-board DC converter to control the on-board DC converter to enter the working state.

[0010] After the on-board DC converter enters the working state, the DCDC is controlled to output high power to charge the low-voltage battery, and the on-board DC converter DCDC works in a high-power state.

[0011] When the on-board DC converter DCDC is working in a high-power state to charge the low-voltage battery, the SOC value of the low-voltage battery is monitored in real time. When the battery voltage reaches the upper limit of the SOC range, the VCU controls the on-board DC converter DCDC to stop outputting power to the low-voltage battery and enters the high-voltage standby state again.

[0012] When it is detected that the power consumption required by the low-voltage load is higher than the power threshold P1, the VCU controls the on-board DC converter to enter the working state. The on-board DC converter DCDC outputs high power to charge the low-voltage battery. The output power range is between P1 and P2, and the output power is determined by the low-voltage load.

[0013] When the on-board DC converter DCDC outputs power to the low-voltage battery in the power range P1-P2, the power consumption required by the low-voltage load is collected in real time. When the power consumption of the low-voltage load is lower than the set threshold P1 and the power level of the low-voltage battery is higher than the lower limit of the SOC interval value, the on-board DC converter DCDC is controlled to enter the standby state again, stop outputting power, and the low-voltage battery provides energy to the low-voltage load.

[0014] A car comprises an on-board DC converter, the on-board DC converter is connected to a low-voltage battery, and the conversion power supply control method of the on-board DC converter is used to control the on-board DC converter to supply power to the low-voltage battery.

[0015] The advantages of the present invention are: low-voltage power supply is provided by a DC battery, and the efficiency of low-voltage power supply is improved by controlling the working time of the vehicle-mounted converter, thereby reducing energy loss during the power supply process. Through a flexible and controllable control strategy, the DCDC is always operated in a high-efficiency area, effectively improving system efficiency, reducing vehicle energy consumption, and improving endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0017] Figure 1 This is a power supply control principle diagram of the low-voltage battery of the present invention when the SOC is in a high power state;

[0018] Figure 2 This is a power supply control principle diagram of the low-voltage battery SOC of the present invention when it is in a low-power state;

[0019] Figure 3 This is a power supply control principle diagram of the present invention when the low-voltage load is in a high power consumption state;

[0020] Figure 4 This is a relationship diagram between the DCDC power and the low-voltage battery SOC of the present invention. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0022] This embodiment provides an efficient DC converter control method, the core control idea of ​​which is that the DC converter is always in a high-efficiency state, and the low-voltage power supply uses a low-voltage battery to provide external reports, and the DC converter is controlled to participate in the control when necessary to achieve high-efficiency operation, avoiding the waste of energy due to low efficiency, and can improve the energy utilization rate of the vehicle and improve the endurance. In this solution, the DC converter is represented by DCDC, and the specific solution is as follows:

[0023] like Figure 1-4 As shown, a conversion power supply control method of an on-vehicle DC converter mainly solves the low working efficiency of DCDC, realizes high-efficiency operation of DCDC and realizes power supply to low-voltage loads. The solution is: a low-voltage battery is used to power the on-vehicle low-voltage load; the on-vehicle DC converter is used to charge the low-voltage battery after converting the power battery; that is, the low-voltage battery is connected to each low-voltage load; the output end of DCDC is connected to the low-voltage battery, and the input end is connected to the power battery; the control end of DCDC is connected to VCU; VCU is used to control the startup state and output power of DCDC; DCDC is used to charge the low-voltage battery after converting the power battery.

[0024] After the vehicle is started, the low-voltage battery is controlled to supply power to the low-voltage load, and the power of the low-voltage battery and the power required by the low-voltage load are collected in real time; the working state of the on-board DC converter is controlled based on the circuit of the low-voltage battery and the power required by the low-voltage load, and the low-voltage battery is used to provide the required power consumption for the on-board low-voltage load.

[0025] When it is detected that the power of the low-voltage battery is in a high power state, it means that the power of the low-voltage battery is sufficient to meet the needs of the low-voltage load, wherein the output power of the low-voltage battery fluctuates between 0 and the threshold value P1 and supplies power to the low-voltage load; the output power of the low-voltage battery is determined based on the size of the low-voltage load, that is, the low-voltage battery is controlled to output the corresponding power between 0 and P1 according to the power required by the low-voltage load. At this time, DCDC does not participate in the control, and the DCDC is controlled to be in a high-voltage standby state.

[0026] The high power state of the low-voltage battery is determined by real-time monitoring of the SOC value of the low-voltage battery, and pre-setting the corresponding SOC interval under the high power state. When the real-time collected SOC value is in the SOC interval, it is judged to be in a high power state. The SOC interval includes a lower limit value and an upper limit value, namely soc1 and soc2. When the power is between soc1-soc2, it is considered to be a high power area, where soc1 and soc2 can be set according to actual calibration.

[0027] When it is detected that the power of the low-voltage battery is lower than the lower limit of the SOC range, the vehicle controller VCU obtains the real-time SOC value through the power sensor, and the VCU sends the control command to the on-board DC converter to control the on-board DC converter to enter the working state. After the on-board DC converter enters the working state, the DCDC is controlled to output high power to charge the low-voltage battery, and the on-board DC converter DCDC works in a high-power state. Since DCDC has high-power and low-power ranges, its efficiency is also high in the high-power range, thereby avoiding the waste of low-power energy. In this solution, the working range after the DCDC is started is always in a high-power state, and it will not work in a low-power state, thereby avoiding the low efficiency of DCDC.

[0028] When the on-board DC converter DCDC is working in a high-power state to charge the low-voltage battery, in order to shut down the high-power operation of DCDC in time, the SOC value of the low-voltage battery is monitored in real time. When the battery voltage reaches the upper limit of the SOC range, the VCU controls the on-board DC converter DCDC to stop outputting power to the low-voltage battery and enter the high-voltage standby state again. When the power required by the low-voltage load is reduced to below the P1 value, it means that the low-voltage battery can supply the required power alone, and if the power is in the high-power range (greater than soc1), the DCDC can stop working at this time, thereby reducing unnecessary working states.

[0029] When it is detected that the power consumption required by the low-voltage load is higher than the power threshold P1, the VCU controls the on-board DC converter to enter the working state, and the on-board DC converter DCDC outputs high power to charge the low-voltage battery. Its output power range is between P1-P2, and the output power is determined by the low-voltage load. When the on-board DC converter DCDC outputs to the low-voltage battery according to the power range P1-P2, the power consumption required by the low-voltage load is collected in real time. When the power consumption of the low-voltage load is lower than the set threshold P1, and the power of the low-voltage battery is higher than the lower limit of the SOC interval value, the on-board DC converter DCDC is controlled to enter the standby state again, stop outputting power, and the low-voltage battery provides energy to the low-voltage load. Since the power provided by the low-voltage battery alone is between 0-P1, if the power required by the low-voltage load is greater than P1, the DCDC is immediately turned on and works in the high-power range. DCDC supplies power to the low-voltage battery. Since the DCDC and the battery are connected in parallel during charging, it is equivalent to DCDC + battery providing power to the outside together. At this time, according to the actual power demand of the low-voltage load, the DCDC is in a high-power operating state to charge the battery while providing charging power to the low-voltage load. At the same time, since the DCDC is still in a high-power operating state, it still has high efficiency.

[0030] Through the above control strategy, when the low-voltage load is powered, the DCDC works in a high-power state regardless of the state, and its working efficiency is always high, and it will not work in a low-power, low-efficiency state, thereby solving the defect of low efficiency caused by directly using DCDC to power the low-voltage load in the prior art.

[0031] An efficient DC converter control method in this embodiment has the key point that it is different from the traditional solution in that it does not distinguish between the power of the low-voltage load and the DCDC works at all times; this patent proposes to avoid the low-power and low-efficiency working area of ​​the DCDC, and timely control the high-power output of the DCDC by monitoring and identifying the SOC of the low-voltage battery or the power consumption of the low-voltage load, so that the DCDC works in the high-efficiency range, effectively improving the system efficiency and improving the energy consumption of the whole vehicle.

[0032] This embodiment proposes a new scheme of a highly efficient DC converter control method. Under the premise of not increasing the cost of the whole vehicle and the number of parts, the power sensor is used to identify the SOC threshold of the low-voltage battery at all times to determine whether to make the DCDC enter the working state for external output. If the SOC threshold is higher than the set value, the low-voltage battery provides energy output for the low-voltage load, avoiding the low-power output interval of the DCDC. When the SOC is lower than the set threshold, the power sensor feeds back to the VCU and controls the DCDC to output high power to charge the low-voltage battery. After charging to the set threshold, the DCDC exits standby and repeats the cycle. The DCDC also identifies the power consumption of the low-voltage load by itself and feeds back to the VCU in real time. When the load power is greater than the set threshold, the VCU controls the DCDC to enter the working state and output high power and high efficiency.

[0033] like Figure 1-4 As shown, this embodiment proposes a flexible DCDC control strategy. When the 12V low-voltage battery is fully charged and the SOC is in a higher range of soc1-soc2 (the low-voltage battery SOC is monitored by a power sensor), the energy required for the low-voltage load of the vehicle comes from the low-voltage battery. The output power of the low-voltage battery is between 0-P1, and the output power is determined by the size of the low-voltage load. At this time, the DCDC is in a high-voltage standby state and does not consume energy. Figure 1 shown.

[0034] 2); until the power of the low-voltage battery is lower than the set threshold soc1, the power sensor sends the soc power signal to the VCU, and the VCU sends the control command to the DCDC to put it into working state, and the power battery outputs high power to the DCDC to charge the low-voltage battery. The charging output power is between P1-P2. After charging to the low-voltage battery soc set threshold 2, the DCDC stops outputting power to the low-voltage battery and enters the standby state again. The power battery stops outputting power to the DCDC; (such as Figure 2 )

[0035] When the power consumption of low-voltage loads such as fans, water pumps, car lights, large screens, etc. is higher than the set threshold value P1 (P1 is monitored by DCDC), VCU controls DCDC to enter the working state, and DCDC outputs high power to the low-voltage battery. The output range is between P1-P2 (P2 is the power upper limit of the low-voltage load). The output power is determined by the low-voltage load, and the low-voltage battery provides energy for the low-voltage load; when the power consumption of the low-voltage load is lower than the set threshold value P1, and the power is higher than soc1, DCDC enters the standby state again, stops outputting power, and the low-voltage battery provides energy to the low-voltage load, such as Figure 3 shown.

[0036] The innovation of the technical solution of this embodiment lies in the control method of DCDC, which cleverly avoids its low-power and low-efficiency working range, but instead uses 12V low-voltage batteries to provide power to low-voltage loads. When the battery SOC is lower than the set threshold, DCDC is controlled to work in the high-power and high-efficiency range; it also lies in the dynamic monitoring of the power consumption of low-voltage loads. When the power consumption of low-voltage loads is higher than the set threshold, DCDC works with high power and high efficiency; when the power consumption of low-voltage loads is lower than the set threshold, DCDC stops output and enters standby mode. Different from the traditional control strategy, without increasing the cost of system components, the flexible and controllable control strategy allows DCDC to always work in the high-efficiency area, effectively improving system efficiency, reducing vehicle energy consumption, and improving endurance.

[0037] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for controlling power supply conversion of a vehicle-mounted DC converter, characterized in that: The low-voltage battery supplies power to the on-board low-voltage load; the on-board DC converter is used to convert the power battery to charge the low-voltage battery; after the vehicle is started, the power of the low-voltage battery and the power required by the low-voltage load are collected in real time; the working state of the on-board DC converter is controlled based on the circuit of the low-voltage battery and the power required by the low-voltage load, and the low-voltage battery is used to provide the required power consumption for the on-board low-voltage load.

2. The method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 1, characterized in that: When it is detected that the power of the low-voltage battery is in a high power state, the output power of the low-voltage battery is between 0 and the threshold P1 to supply power to the low-voltage load; the output power of the low-voltage battery is determined based on the size of the low-voltage load; at this time, the DCDC is controlled to be in a high-voltage standby state.

3. The method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 2, characterized in that: The high power state of the low-voltage battery is determined by real-time monitoring of the SOC value of the low-voltage battery, presetting the corresponding SOC interval under the high power state, and determining that the battery is in a high power state when the real-time collected SOC value is within the SOC interval.

4. The method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 3, characterized in that: When it is detected that the power of the low-voltage battery is lower than the lower limit of the SOC range, the vehicle controller VCU obtains the real-time SOC value through the power sensor, and the VCU sends a control command to the on-board DC converter to control the on-board DC converter to enter the working state.

5. The method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 4, characterized in that: After the on-board DC converter enters the working state, the DCDC is controlled to output high power to charge the low-voltage battery, and the on-board DC converter DCDC works in a high-power state.

6. A method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 4 or 5, characterized in that: When the on-board DC converter DCDC is working in a high-power state to charge the low-voltage battery, the SOC value of the low-voltage battery is monitored in real time. When the battery voltage reaches the upper limit of the SOC range, the VCU controls the on-board DC converter DCDC to stop outputting power to the low-voltage battery and enters the high-voltage standby state again.

7. A method for controlling power supply conversion of a vehicle-mounted DC converter according to any one of claims 1 to 5, characterized in that: When it is detected that the power consumption required by the low-voltage load is higher than the power threshold P1, the VCU controls the on-board DC converter to enter the working state. The on-board DC converter DCDC outputs high power to charge the low-voltage battery. The output power range is between P1 and P2, and the output power is determined by the low-voltage load.

8. The method for controlling power supply conversion of a vehicle-mounted DC converter according to claim 7, characterized in that: When the on-board DC converter DCDC outputs power to the low-voltage battery in the power range P1-P2, the power consumption required by the low-voltage load is collected in real time. When the power consumption of the low-voltage load is lower than the set threshold P1 and the power level of the low-voltage battery is higher than the lower limit of the SOC interval value, the on-board DC converter DCDC is controlled to enter the standby state again, stop outputting power, and the low-voltage battery provides energy to the low-voltage load.

9. A car, characterized in that: The automobile comprises an on-board DC converter, which is connected to a low-voltage battery. The on-board DC converter is controlled to supply power to the low-voltage battery by using the conversion power supply control method of the on-board DC converter as described in any one of claims 1 to 8.

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