CN-122009136-A - Dynamic adjustment method and system for power generation efficiency under low-temperature working condition of hybrid vehicle

CN122009136ACN 122009136 ACN122009136 ACN 122009136ACN-122009136-A

Abstract

The invention relates to the technical field of new energy automobile energy management, in particular to a dynamic adjustment method and a dynamic adjustment system for power generation efficiency under a low-temperature working condition of a hybrid vehicle. The method fully utilizes the characteristic of sufficient heat dissipation capacity in a low-temperature environment, and converts surplus mechanical energy into heat dissipation instead of electric energy by dynamically adjusting the power generation efficiency of the motor, so that the electric power of an input battery is quickly reduced on the premise of not changing the output torque of the shaft end of the generator, the risk of sudden drop of driving power is effectively avoided, and meanwhile, the average efficiency loss caused by continuous reservation is avoided.

Inventors

ZHAO YA
ZHU HAO
YAO YULIANG
HUANG KECHENG

Assignees

奇瑞汽车股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (10)

1. The dynamic adjustment method for the power generation efficiency of the hybrid vehicle under the low-temperature working condition is characterized by comprising the following steps of: step one, acquiring vehicle running state parameters in real time, wherein the vehicle running state parameters at least comprise maximum allowable battery charging power Current power generation of generator Driving power Battery temperature And drive motor temperature ; Step two, based on the battery temperature Judging whether the working condition is in a low temperature condition or not; Step three, the controller calculates the real-time charging margin difference value The calculation formula is as follows: under the low-temperature working condition, according to the difference value of the charging power margin And driving power variation trend, dynamically determining target power generation efficiency Wherein the target power generation efficiency Lower than the current optimal power generation efficiency And the target power generation efficiency With the charging power margin difference Is reduced by the reduction of the drive power or the increase of the drive power decrease trend; Step four, controlling the power generation motor to achieve the target power generation efficiency By adjusting the motor Shaft current And Shaft current On the premise of maintaining the change rate of the mechanical torque of the output shaft within a preset range, the internal loss of the motor is increased, and the excessive mechanical energy is converted into heat energy, so that the actual output electric power meets the constraint condition ; Step five, monitoring the temperature of the driving motor And dynamically adjusting the target power generation efficiency according to the temperature constraint Lower limit of (2).
2. The method of claim 1, wherein the step of determining whether the battery is in a low temperature condition based on the battery temperature comprises: First, the battery temperature is set And preset low temperature threshold Comparing; Second, when When the low-temperature efficiency adjustment mode is judged to be entered; Finally, when When the conventional power reservation control strategy is executed.
3. The method of claim 1, wherein the step of dynamically determining the target power generation efficiency comprises: Firstly, according to the charging power margin difference value And (3) carrying out risk classification: First, when When the base target efficiency is ; Second, when In the time-course of which the first and second contact surfaces, By at least one of Linear interpolation is determined between the preset intermediate efficiency value and the preset intermediate efficiency value; Third step, when In the time-course of which the first and second contact surfaces, ; Second, according to the rate of change of the driving power Trend compensation is performed when When it is, according to the formula ; Further reducing target efficiency, wherein Is the calibration coefficient.
4. The method of claim 1, wherein the adjusting the motor Shaft current The step of distributing the proportion of the shaft current comprises the following steps: first, the electromagnetic torque is maintained to be output On the premise that the change rate is within a preset range, the change rate is increased towards the weak magnetic direction Shaft current Absolute value of (2); second, adjust correspondingly Shaft current To compensate for Influence of shaft current variation on torque; Finally, the stator current amplitude is made Increase copper loss due to increase in size The power generation efficiency is reduced.
5. The method of claim 1, wherein the step of dynamically adjusting the target lower power generation efficiency limit in accordance with the temperature constraint comprises: first, a lower efficiency limit is calculated from the current motor temperature: , Wherein the method comprises the steps of For the purpose of the calibration coefficient, And The lower limit and the upper limit of the temperature are respectively; secondly, the target power generation efficiency is limited to not lower than the lower efficiency limit: 。
6. the method as recited in claim 1, further comprising: When the battery heating system requests heating and is in a very low temperature working condition And when the target power generation efficiency is further reduced, the extra heat generated by the generator is directionally transmitted to the battery pack through the cooling liquid loop for battery preheating.
7. The utility model provides a mix dynamic adjustment system of motor vehicle low temperature operating mode generating efficiency which characterized in that includes: the state acquisition module is used for acquiring the maximum allowable charging power of the battery in real time Current power generation of generator Driving power Battery temperature And drive motor temperature ; The working condition judging module is used for judging the temperature of the battery Judging whether to enter a low-temperature efficiency adjustment mode; an efficiency decision module for determining a difference value according to the charging power margin in the low temperature efficiency adjustment mode And driving power variation trend, dynamically determining target power generation efficiency Wherein the target power generation efficiency Less than optimal power generation efficiency ; A motor control module for controlling the motor by adjusting the motor Shaft current And Shaft current Controlling the power generation motor to achieve the target power generation efficiency The operation is carried out, and the surplus mechanical energy is converted into heat energy on the premise of maintaining the change rate of the mechanical torque within a preset range; a thermal management coordination module for monitoring the temperature of the driving motor And dynamically adjusting the target power generation efficiency Lower limit of (2).
8. The system of claim 7, wherein the efficiency decision module comprises: a risk assessment unit for calculating a risk of the battery according to the charging power margin difference Performing risk classification and determining base target efficiency ; Trend compensation unit for compensating for the change rate of the driving power For the basic target efficiency Performing dynamic correction; a thermal restraint unit for controlling the temperature of the driving motor Calculating a lower efficiency limit and limiting the target power generation efficiency Not lower than the lower limit.
9. The system of claim 7, wherein the motor control module is a permanent magnet synchronous generator controller that is adjusted by a vector control algorithm Shaft current And Shaft current And operating the motor at a working point corresponding to the target efficiency.
10. A vehicle controller comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, implements the method of any one of claims 1 to 6.

Description

Dynamic adjustment method and system for power generation efficiency under low-temperature working condition of hybrid vehicle Technical Field The invention relates to the technical field of new energy automobile energy management, in particular to a dynamic adjustment method and a dynamic adjustment system for power generation efficiency under a low-temperature working condition of a hybrid vehicle. Background During operation of the hybrid vehicle, the engine drives the generator to generate electrical energy, a portion of which is used to drive the motor and a portion of which is used to charge the battery. The charging capability of the battery is significantly affected by temperature, and the maximum charging power acceptable by the battery is greatly reduced in a low-temperature environment in winter, so that lithium precipitation is prevented, safety is ensured, and the service life of the battery is prolonged. The decrease in maximum allowable battery charge power during low temperature conditions may result in the generated power of the engine easily approaching or exceeding this limit even at conventional levels. When the drive power drops rapidly, there is a risk of power imbalance in the system due to engine power response lag, which may trigger engine protection or cause battery overcharge. The prior art generally adopts a reservation strategy based on a power difference, namely, when the generated power is close to the maximum allowable charging power of a battery, the power set value of the generator is actively reduced, and a part of buffering capacity is reserved. However, in a low-temperature scenario, the maximum allowable charging power of the battery is low, and the power generation efficiency is seriously lost due to continuous reservation, so that the engine works in a low-efficiency interval more, and the oil consumption is increased. On the other hand, in a low-temperature environment, the capacity of the vehicle cooling system is relatively sufficient, and the motor and the electric control system have larger heat bearing allowance. The prior art fails to effectively utilize this feature to solve the above contradiction. Therefore, an optimization control strategy for low-temperature working conditions is needed to maximize the power generation efficiency on the premise of ensuring the safety of the system. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a dynamic adjustment method and a dynamic adjustment system for the power generation efficiency of a hybrid vehicle under a low-temperature working condition. The method fully utilizes the characteristic of sufficient heat dissipation capacity in a low-temperature environment, and converts surplus mechanical energy into heat dissipation instead of electric energy by dynamically adjusting the power generation efficiency of the motor, so that the electric power of an input battery is quickly reduced on the premise of not changing the output torque of the shaft end of the generator, the risk of sudden drop of driving power is effectively avoided, and meanwhile, the average efficiency loss caused by continuous reservation is avoided. In order to achieve the above purpose, the invention adopts the following technical scheme: a dynamic adjustment method for the power generation efficiency of a hybrid vehicle under a low-temperature working condition comprises the following steps: step one, acquiring vehicle running state parameters in real time, wherein the vehicle running state parameters at least comprise maximum allowable battery charging power Current power generation of generatorDriving powerBattery temperatureAnd drive motor temperature; Step two, based on the battery temperatureJudging whether the working condition is in a low temperature condition or not; Step three, under the low-temperature working condition, according to the difference value of the charging power margin And driving power variation trend, dynamically determining target power generation efficiencyWherein the target power generation efficiencyLower than the current optimal power generation efficiencyAnd the target power generation efficiencyWith the charging power margin differenceIs reduced by the reduction of the drive power or the increase of the drive power decrease trend; Step four, controlling the power generation motor to achieve the target power generation efficiency By adjusting the motorShaft currentAndShaft currentOn the premise of maintaining the change rate of the mechanical torque of the output shaft within a preset range, the internal loss of the motor is increased, and the excessive mechanical energy is converted into heat energy, so that the actual output electric power meets the constraint condition; Step five, monitoring the temperature of the driving motorAnd dynamically adjusting the target power generation efficiency according to the temperature constraintLower limit of (2). Preferably, the st