Intelligent charging control method for new energy automobile

Abstract

The invention discloses an intelligent charging control method for a new energy automobile. The intelligent charging control method comprises the following steps that S10, a key is off, and high voltage is turned off; step S20, judging whether intelligent power supply is triggered or not, if so, triggering the intelligent power supply after the travelling crane is powered off, and then performing the step S30, and if not, repeating the judgment; s30, judging whether the SOC of the high-voltage battery is lower than a threshold value or not, if not, executing the step S40, and if yes, executing the step S70; and S40, after delaying for 3 minutes, controlling the whole vehicle to be in high voltage again to charge the low-voltage storage battery. The low-voltage storage battery is ensured to be fed or have a feeding trend even if the whole vehicle runs under the extreme working condition, meanwhile, the whole vehicle is also perfectly ensured not to lie down due to the feeding of the low-voltage storage battery even under the extreme working condition, the capability and the function robustness of the product in dealing with the extreme working condition are improved, the economic loss of a user is avoided, and the user experience is improved. And the vehicle use experience of the user is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicles, and in particular, relates to an intelligent power replenishment control method for new energy vehicles. Background Art

[0002] New energy vehicles are equipped with high-voltage power batteries to power the high-voltage components of the vehicle, and the controllers of each component run on a low-voltage platform, because conventional control system chips all run on low-voltage systems. In addition to the three-electric system, other control systems of new energy vehicles also generally continue to use the control system of fuel vehicles, which means that the components all work on a low-voltage platform. New energy vehicles usually do not have engines. Even if hybrid models are equipped with engines, they will not be equipped with small generators that are not advantageous in terms of efficiency, reliability, and size. New energy vehicles use DC-DC converters (hereinafter referred to as "DCDC") that convert high-voltage DC to low-voltage DC to ensure the load power balance on the low-voltage side and ensure the normal operation of low-voltage loads, especially controllers.

[0003] The DCDC output capacity is usually matched and selected according to the low-voltage load conditions. If the actual maximum output capacity of the DCDC matched with the whole vehicle cannot fully cover the low-voltage power consumption under the most extreme working conditions, then the battery on the low-voltage side will actually discharge gradually, thereby consuming the battery energy, resulting in the risk of power feeding of the low-voltage battery. In the actual design and development of the whole vehicle, all the most extreme working conditions are usually not taken into account due to the hardware cost of the whole vehicle, so the state of the whole vehicle under extreme working conditions cannot be strongly guaranteed.

[0004] New energy vehicles usually have an intelligent charging function. Conventional intelligent charging functions are based on periodic timed wake-up. After the VCU wakes up, it controls the high voltage to close to replenish the low-voltage battery. The problem is that when the vehicle is running under extreme working conditions, the actual low-voltage battery has already shown a trend of power decline or feeding. At this time, if you still wait for a period of time after the periodic wake-up of the intelligent charging before turning on the high voltage to replenish the low-voltage battery, the static power consumption of each controller after sleep will cause the power and voltage of the low-voltage battery to further decrease. When the low-voltage battery voltage is lower than the threshold, each controller, especially the core controller of the three-electric system, will not be able to work normally, and the vehicle will completely lose the ability to turn on high voltage. The energy on the high-voltage side will also not be able to flow to the low-voltage side. At this time, the vehicle will completely break down. Summary of the invention

[0005] The present invention provides a new energy vehicle intelligent power replenishment control method, which solves the problems raised in the above background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a new energy vehicle intelligent power replenishment control method, comprising the following steps: Step S10, key off, high voltage; Step S20, determining whether the intelligent charging is triggered, if so, triggering the intelligent charging after the vehicle is powered off, and then proceeding to step S30, if not, repeating the determination; Step S30, determining whether the high-voltage battery SOC is lower than a threshold value, if not, proceeding to step S40, if yes, proceeding to step S70; Step S40, after a delay of 3 minutes, the vehicle is controlled to be powered up again with high voltage to replenish the low voltage battery; Step S50, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S60, otherwise repeat the determination; Step S60, VCU controls to exit the trigger-type intelligent power replenishment control; Step S70, the VCU controls and starts the APU to supplement the high-voltage battery and supply power to the high-voltage accessories, and supplements the low-voltage battery through the DCDC.

[0007] Preferably, the control logic for determining whether to trigger intelligent power replenishment in step S20 is as follows: Step S21, determine whether the vehicle has exited the driving ready state and has lowered the high voltage. If yes, proceed to the next step. If no, repeat the determination. Step S22, determining whether the door lock state sent by the vehicle body controller is locked, if yes, proceed to the next step, if no, repeat the determination; Step S23, determining whether the low-voltage battery voltage at the high-voltage moment is lower than a threshold value, and the voltage difference at the initial power-on moment is higher than the threshold value, if so, proceed to the next step, if not, repeat the determination; Step S24, determine whether the vehicle is not plugged in for charging, and whether the battery discharge capacity is higher than a threshold value. If so, trigger the intelligent charging after the vehicle is powered off. If not, repeat the determination.

[0008] Preferably, the step S70 further includes the following steps: Step S71, VCU issues a low-power generation instruction to APU; Step S72, the APU performs power generation according to the VCU instruction; Step S73, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S74, otherwise repeat the determination; Step S74, the VCU controls the APU to shut down, and does not exit the triggered intelligent power replenishment control.

[0009] The beneficial effects of adopting the above technical solution are: The present invention designs an intelligent power replenishment control strategy that integrates periodic and triggered monitoring, and covers the capability boundary of the hardware itself through the control strategy at the software level, thereby ensuring that even if the low-voltage battery is fed or has a feeding trend after the whole vehicle is running under extreme working conditions, the software can also use the control algorithm to avoid the whole vehicle breaking down due to further power consumption of the low-voltage battery, that is, it does not increase the cost of the whole vehicle. At the same time, it also perfectly ensures that even under extreme working conditions, the whole vehicle will not break down due to the feeding of the low-voltage battery, thereby improving the product's ability to cope with extreme working conditions and functional robustness, avoiding economic losses for users, and ensuring users' vehicle experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is the overall control strategy flow chart provided by the present invention; Figure 2 It is a flow chart of trigger-type intelligent power replenishment enable judgment. DETAILED DESCRIPTION

[0011] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation. Example 1

[0012] Specifically, Figure 1 As shown, a new energy vehicle intelligent power replenishment control method includes the following steps: Step S10, key off, high voltage; Step S20, determining whether the intelligent charging is triggered, if so, triggering the intelligent charging after the vehicle is powered off, and then proceeding to step S30, if not, repeating the determination; Step S30, determining whether the high-voltage battery SOC is lower than a threshold value, if not, proceeding to step S40, if yes, proceeding to step S70; Step S40, after a delay of 3 minutes, the vehicle is controlled to be powered up again with high voltage to replenish the low voltage battery; Step S50, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S60, otherwise repeat the determination; Step S60, VCU controls to exit the trigger-type intelligent power replenishment control; Step S70, the VCU controls and starts the APU to supplement the high-voltage battery and supply power to the high-voltage accessories, and supplements the low-voltage battery through the DCDC.

[0013] It should be noted that when the VCU determines that the trigger-type intelligent power replenishment conditions are met after the vehicle is powered off, the VCU will control the vehicle to wake up and issue a high-voltage command to the BMS to perform a high-voltage closing action. When the high-voltage system is closed normally, an enable command is issued to the DCDC, and the DCDC starts to output a constant voltage to replenish the low-voltage battery. In detail, for step S30, if the high-voltage battery power is extremely low when the vehicle is powered off, and the SOC is lower than the threshold, for the extended-range electric vehicle, in order to ensure that the low-voltage battery power of the vehicle will not be further attenuated due to long-term storage, thereby causing the vehicle controller and other components to fail to work normally, and then causing the risk of the vehicle being unable to normally supply high voltage, thereby causing the vehicle to break down, then after the trigger-type intelligent power replenishment enabling condition is judged to be established, the VCU will control the start of the APU to replenish power for the high-voltage battery and supply power to the high-voltage accessories, and replenish power for the low-voltage battery through the DCDC. When the low-voltage battery voltage is higher than the threshold, the VCU will control the APU to shut down, and the vehicle will enter the periodic awakening intelligent power replenishment monitoring from high-voltage sleep; In addition, regarding the APU control startup described above, since the higher the engine speed, the louder the noise, and the greater the APU power generation, the more fuel is consumed, in order to take into account the vehicle's economy and environmental friendliness, the APU required power generation issued by the VCU should be kept at a low power (such as 2kW) to ensure that the APU generates less noise during operation and consumes as little fuel as possible. This not only ensures timely charging of the low-voltage battery to avoid vehicle breakdown, but also ensures the user's economy and environmental friendliness.

[0014] The step S70 further includes the following steps: Step S71, VCU issues a low-power generation instruction to APU; Step S72, the APU performs power generation according to the VCU instruction; Step S73, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S74, otherwise repeat the determination; Step S74, the VCU controls the APU to shut down, but does not exit the trigger-type intelligent power replenishment control. ; It should be noted that, for step S50 and step S73, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery. When the power of the low-voltage battery is less than 20%, if the whole vehicle is in the ON gear and not in high voltage, if more low-voltage electrical appliances are turned on, the low-voltage load may cause the low-voltage battery to drop instantly. At this time, the low-voltage battery voltage will be lower than 11V. At this time, each controller including the VCU has gradually begun to fail to work normally. Therefore, in order to ensure that the whole vehicle can normally operate at high voltage, the low-voltage side is supplemented with power from the high-voltage side. It is necessary to ensure that the voltage of the low-voltage battery is not lower than 11V, so that the power of the low-voltage battery can be guaranteed to be higher than 20%, thereby ensuring that the whole vehicle can cope with the risk of sudden power drop caused by the high low-voltage load power consumption in extreme working conditions, and each control unit can work normally, ensuring that the high-voltage side is closed normally, thereby activating the energy state of the high and low voltage sides.

[0015] In this embodiment, if all low-voltage loads are in operation, when the low-voltage load is higher than the DCDC output capacity, the power consumption of the low-voltage load will cause the battery power to begin to decrease. In order to improve the power preservation capability of the low-voltage battery and prevent the static power consumption of each control unit after the low-voltage battery power is lower than the threshold, causing the low-voltage battery power to further decrease, thereby causing the risk of the entire vehicle breaking down, the VCU detects the low-voltage battery voltage when the high voltage is lowered. If the conditions are met, it directly starts to replenish the low-voltage battery, rather than the traditional intelligent replenishment function that starts the timed wake-up detection after the VCU has been dormant for a period of time, and then performs relevant control. Example 2

[0016] Specifically, Figure 2 As shown, the control logic for determining whether to trigger intelligent power replenishment in step S20 is as follows: Step S21, determine whether the vehicle has exited the driving ready state and has lowered the high voltage. If yes, proceed to the next step. If no, repeat the determination. It should be noted that the vehicle has exited the driving ready state and lowered the high voltage in order to determine that the high voltage of the vehicle has been disconnected. When the high voltage is disconnected, the DCDC has stopped outputting power to the low-voltage battery on the low-voltage side. Step S22, determining whether the door lock state sent by the vehicle body controller is locked, if yes, proceed to the next step, if no, repeat the determination; It should be noted that the door lock status sent by the body controller is locked in order to determine that the driver has the subjective intention to leave the vehicle and has locked the vehicle to leave. This can ensure the driver's safety and prevent people from performing some operations in the vehicle or without the subjective intention to leave the vehicle, which may cause high-voltage safety risks. Step S23, determining whether the low-voltage battery voltage at the high-voltage moment is lower than a threshold value, and the voltage difference at the initial power-on moment is higher than the threshold value, if so, proceed to the next step, if not, repeat the determination; It should be noted that when the low-voltage battery voltage is lower than the threshold at the time of high-voltage, it is to determine that the low-voltage battery has indeed experienced a decrease in power and the voltage is lower than the safe voltage value. Only then will it be further considered whether to trigger the intelligent power replenishment; In addition, the voltage difference at the initial moment of power-on is higher than the threshold in order to identify whether the low-voltage battery itself has experienced capacity attenuation due to long-term use, rather than excessive power consumption on the low-voltage side load, which causes the DCDC output power to be unable to cover the low-voltage power consumption, thereby causing the battery power to drop. This avoids the ineffective intelligent power replenishment due to problems with the low-voltage battery itself. Under this working condition, the VCU will normally report a low-voltage battery voltage fault and send a low-voltage battery voltage status alarm signal to the instrument. The instrument parses the low-voltage battery voltage alarm signal sent by the VCU and drives the low-voltage battery voltage alarm light to remind the driver that the low-voltage battery voltage is abnormal and needs to be checked and processed. Step S24, determine whether the vehicle is not plugged in for charging, and whether the battery discharge capacity is higher than the threshold. If so, trigger the intelligent charging after the vehicle is powered off. If not, repeat the determination. It should be noted that when the vehicle is plugged in for charging, the high-voltage system is closed, and the DCDC will perform voltage conversion normally, converting the high-voltage side voltage into low voltage to replenish the low-voltage battery, so there is no need to trigger the intelligent charging to replenish the low-voltage battery at this time; In addition, the battery discharge capacity is higher than the threshold. The VCU judges the battery discharge capacity to prevent the battery from being over-discharged due to the DCDC still outputting after the high voltage is applied when the battery is not allowed to discharge. Therefore, when the battery is not allowed to discharge, the high voltage closing should be prohibited to allow the battery to discharge to avoid over-discharge of the battery. In this embodiment, after the VCU determines that the above conditions are met, it triggers the intelligent power replenishment after the vehicle is powered off. After a delay of 3 minutes, it controls the entire vehicle to be powered on again with high voltage to replenish the low-voltage battery.

[0017] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A new energy vehicle intelligent power replenishment control method, characterized in that: The following steps are involved: Step S10, key off, high voltage; Step S20, determining whether the intelligent charging is triggered, if so, triggering the intelligent charging after the vehicle is powered off, and then proceeding to step S30, if not, repeating the determination; Step S30, determining whether the high-voltage battery SOC is lower than a threshold value, if not, proceeding to step S40, if yes, proceeding to step S70; Step S40, after a delay of 3 minutes, the vehicle is controlled to be powered up again with high voltage to replenish the low voltage battery; Step S50, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S60, otherwise repeat the determination; Step S60, VCU controls to exit the trigger-type intelligent power replenishment control; Step S70, the VCU controls and starts the APU to supplement the high-voltage battery and supply power to the high-voltage accessories, and supplements the low-voltage battery through the DCDC.

2. According to claim 1, a new energy vehicle intelligent power replenishment control method is characterized in that: The control logic for determining whether to trigger intelligent power replenishment in step S20 is as follows: Step S21, determine whether the vehicle has exited the driving ready state and has lowered the high voltage. If yes, proceed to the next step. If no, repeat the determination. Step S22, determining whether the door lock state sent by the vehicle body controller is locked, if yes, proceed to the next step, if no, repeat the determination; Step S23, determining whether the low-voltage battery voltage at the high-voltage moment is lower than a threshold value, and the voltage difference at the initial power-on moment is higher than the threshold value, if so, proceed to the next step, if not, repeat the determination; Step S24, determine whether the vehicle is not plugged in for charging, and whether the battery discharge capacity is higher than a threshold value. If so, trigger the intelligent charging after the vehicle is powered off. If not, repeat the determination.

3. The intelligent power replenishment control method for new energy vehicles according to claim 1 is characterized in that: The step S70 further includes the following steps: Step S71, VCU issues a low-power generation instruction to APU; Step S72, the APU performs power generation according to the VCU instruction; Step S73, the VCU will look up the table to determine the actual power of the low-voltage battery based on the OCV curve of the low-voltage battery at different temperatures and the voltage of the battery, and determine whether the voltage of the low-voltage battery is higher than the threshold. If so, proceed to step S74, otherwise repeat the determination; Step S74, the VCU controls the APU to shut down, and does not exit the triggered intelligent power replenishment control.

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