Electricity generation control method of extended-range vehicle under different electricity generation scenes

Abstract

The application discloses a power generation control method of a range extending vehicle under different power generation scenes, and the main design concept of the application is that, through identification of a driver driving demand scene, a power battery SOC compensation scene, a power battery power deficiency scene, an engine light-off working condition scene, an external demand scene and the like, corresponding power generation demand power is acquired, and the range extender power generation power is arbitrated according to whether the current vehicle is in the light-off working condition. The application realizes automatic switching of the range extender under constant power and power following power generation working conditions through identification of multiple actual power generation scenes, which not only facilitates control of battery SOC balance and prevents overcharging and overdischarging of the battery, but also can comprehensively make oil-electricity intelligent decisions under multiple working conditions. Further, the target torque working condition point of the range extender is acquired by using the range extender power generation power calculation result, the range extender is kept running on a relatively optimal working curve, and therefore the intelligence and economy of the range extending vehicle are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of range-extended vehicle technology, and in particular to a power generation control method for range-extended vehicles under different power generation scenarios. Background Technology

[0002] As an important branch of new energy vehicles, range-extended electric vehicles (REEVs) are based on pure electric vehicles (EVs) by adding a range extender to increase their driving range. The range extender couples the engine and generator and decouples them from the wheels, utilizing the engine's operating range to achieve fuel savings. Due to their relatively simple structure and control, smooth driving, and low operating costs, REEVs are gaining an increasingly larger market share.

[0003] In typical range-extending technology routes, power generation control is divided into constant power strategy and multi-point strategy. The main disadvantage of this technical solution is that the charging and discharging current of the battery varies greatly with the change of operating conditions, which can easily lead to overcharging and over-discharging. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a power generation control method for range-extended vehicles under different power generation scenarios, so as to solve the aforementioned technical problems.

[0005] The technical solution adopted in this invention is as follows:

[0006] This invention provides a power generation control method for range-extended vehicles under different power generation scenarios, wherein the power generation scenarios include at least one of the following: driver driving demand scenario, power battery SOC compensation scenario, power battery insufficient power scenario, engine ignition condition scenario, and external demand scenario.

[0007] Driving scenario: When the SOC of the power battery is lower than the preset first threshold, or when the SOC is lower than the preset second threshold and the vehicle speed is higher than the corresponding set threshold, the range extender is controlled to start and obtain the first power.

[0008] Power battery SOC compensation scenario: When the power battery SOC is less than the predetermined SOC threshold, the range extender is controlled to start and obtain a second power for battery charging, wherein the second power is positively correlated with the SOC deviation and the battery charging capacity.

[0009] Insufficient power battery: When the SOC is greater than the second threshold and the vehicle is in pure electric mode, if the driver's power demand is greater than the power battery discharge power, the range extender will be activated and a third power source will be obtained as supplementary power.

[0010] Engine ignition scenario: When the range extender starts for the first time, it generates electricity according to the preset fourth power.

[0011] External demand scenario: When the range extender is started by external demand, if the SOC is less than the preset third threshold, the range extender will be controlled to generate electricity at the preset fifth power.

[0012] Based on the power values ​​obtained from different scenarios, the range extender's power output is determined according to the current operating conditions, specifically including:

[0013] If it is determined that the current condition is ignition-in operation, then only the fourth power is used as the range extender's power output; if it is determined that the current condition is not ignition-in operation, then the maximum value among the first power, the third power, and the fifth power is taken, and the maximum value is summed with the second power and the current high-voltage load demand power as the range extender's power output.

[0014] In at least one of the possible implementations, the first power is calculated according to the following formula:

[0015] P1=

[0016] Where P1 is the first power, N is the driver's torque requirement, T is the current drive motor speed, and Eff is the range extender system efficiency.

[0017] In at least one of the possible implementations, the SOC deviation = target SOC - actual SOC; the battery charging capacity = battery charging power limit - motor recovery power.

[0018] In at least one of the possible implementations, the third power = driver demand power - power battery discharge power.

[0019] In at least one of the possible implementations, in an external demand scenario, if the SOC is greater than the third threshold, the range extender is controlled to enter an idling state.

[0020] In at least one of the possible implementations, after obtaining the power output of the range extender, the target speed of the range extender is determined by querying a power-speed mapping table pre-calibrated based on the economic operating curve, and the target torque of the range extender is obtained based on the target speed.

[0021] Compared with existing technologies, the main design concept of this invention lies in identifying multiple scenarios, including driver driving demand scenarios, power battery SOC compensation scenarios, power battery insufficient power scenarios, engine ignition conditions, and external demand scenarios, to obtain the corresponding power generation demand. The range extender's power generation capacity is then determined by arbitrating whether the vehicle is currently in an ignition condition. By identifying various actual power generation scenarios, this invention enables the range extender to automatically switch between constant power and power-following power generation conditions. This not only facilitates the control of battery SOC balance and prevents overcharging and over-discharging, but also allows for intelligent decision-making based on multiple operating conditions. Furthermore, the target torque operating point of the range extender is obtained using the calculated power generation capacity, maintaining the range extender operating on a relatively optimal working curve, thereby significantly improving the intelligence and economy of range-extended vehicles. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the range extender power generation arbitration decision provided in an embodiment of the present invention. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] This invention proposes an embodiment of a power generation control method for range-extended vehicles under different power generation scenarios, specifically including: driver driving demand scenario, power battery SOC compensation scenario, power battery insufficient power scenario, engine ignition condition scenario, and external demand scenario.

[0026] For driving scenarios, when the SOC of the power battery is lower than the preset first threshold, or the SOC is lower than the preset second threshold (the second threshold is greater than the first threshold) and the vehicle speed is higher than the corresponding set threshold, the range extender is controlled to start and obtain the first power to meet the driver's driving needs. In this scenario, the driving power generation demand, i.e., the first power P1, can be obtained as follows.

[0027] To elaborate, when controlling power generation based on driver's driving demand, the calculation method for the driver's driving demand power, i.e., P1, can be referenced as follows:

[0028] P1=

[0029] Where P1 is the driver's driving power requirement, N is the driver's torque requirement, T is the current drive motor speed, and Eff is the range extender system efficiency.

[0030] For power battery SOC compensation scenarios, when the power battery SOC is below a relatively low level (which can be quantized according to a corresponding set threshold), the range extender is activated and a second power source is acquired for battery charging. This second power source is calculated based on the SOC deviation (target SOC - actual SOC) and the battery charging capacity (battery charging power limit P). Chrg -The SOC (State of Charge) is positively correlated with the power recovered by the motor. In practice, the SOC compensation power, i.e., the second power P2, can be obtained by looking up a two-dimensional table.

[0031] To elaborate, when power generation control is based on battery SOC compensation, the range extender's power generation P2, which compensates for the SOC, is related to the SOC deviation (target SOC - actual SOC) and the battery charging capacity (battery charging power limit P). Chrg -The power recovered by the motor is positively correlated with the power recovered by the motor, which can be obtained by referring to the following schematic pre-built two-dimensional table:

[0032]

[0033] For scenarios where the power battery power is insufficient, when the SOC is greater than the second threshold, the vehicle is in pure electric mode. If at this time the driver's power demand P is greater than the power battery discharge power P, dischrg In such cases, the range extender is activated and a third power source is acquired as supplementary power.

[0034] To elaborate, when power generation control is based on insufficient battery power, the range extender supplements the power, i.e., the third power P3=PP. Dischrg .

[0035] For the engine ignition scenario, that is, when the range extender starts for the first time, the main goal of the range extender is to generate a large amount of combustion heat. In order to get the aftertreatment into working state as soon as possible, the engine needs to work at a specific operating point for a period of time to quickly increase the exhaust temperature and activate the catalytic converter. At this time, the power generation condition is to generate electricity according to the preset fourth power, that is, the predetermined first constant power point P4.

[0036] For external demand scenarios, when the range extender is started by external demand (such as warm-up requests, air conditioning heating, carbon canister desorption, etc.): if the SOC is greater than the preset third threshold, the range extender is controlled to enter the idle state, at which time the power generation is 0; if the SOC is less than the preset third threshold, the range extender is controlled to enter the power generation state and generate power according to the preset fifth power, that is, the predetermined second constant power point P5.

[0037] To elaborate further, for power generation control based on external demand, if there is no driver-driven power generation demand as mentioned above, power generation will be carried out in a fixed-point mode (preset constant value). In this case, the power generation is only used to meet external demand, rather than to provide power or recharge the battery. To further explain, range-extended vehicles with smaller power battery capacity are usually fuel-powered. In this case, the heat source for heating the cabin can be the engine coolant. The range extender can be started and controlled by external request, thereby eliminating the need for the PTC device in the cabin.

[0038] Combination Figure 1 As shown, since the ignition power generation has the highest priority, if it is determined that the current condition is ignition, only the fourth power is used as the range extender's power generation. However, if it is determined that the current condition is not ignition and there are several power generation scenarios, such as the power demand of the high-voltage load (P6), the following arbitration needs to be performed: take the maximum value of the first power, the third power, and the fifth power, and sum it with the second power and the current high-voltage load's power demand as the range extender's power generation.

[0039] Finally, it can be added that after obtaining the aforementioned range extender's power output, the range extender's speed can be determined and the target torque calculated by consulting a pre-calibrated "power-speed" mapping table based on the economic operating curve, as shown below:

[0040]

[0041] After obtaining the target speed of the range extender from the table, and then combining it with the formula T=P*9550 / N (where T is torque, P is power, and N is speed), the target torque of the range extender can be obtained, which means determining the operating point of the range extender for power generation.

[0042] In summary, the main design concept of this invention lies in identifying multiple scenarios, including driver driving demand scenarios, power battery SOC compensation scenarios, power battery insufficient power scenarios, engine ignition conditions, and external demand scenarios, to obtain the corresponding power generation demand. The range extender's power generation capacity is then determined by arbitrating whether the vehicle is currently in an ignition condition. By identifying various actual power generation scenarios, this invention enables the range extender to automatically switch between constant power and power-following power generation conditions. This not only facilitates the control of battery SOC balance and prevents overcharging and over-discharging, but also allows for intelligent decision-making based on multiple operating conditions. Furthermore, the target torque operating point of the range extender is obtained using the calculated power generation capacity, maintaining the range extender operating on a relatively optimal working curve, thereby significantly improving the intelligence and economy of range-extended vehicles.

[0043] In this invention, when directional terms are mentioned, they are relative concepts based on the embodiments. Furthermore, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0044] The above description of the structure, features, and effects of the present invention is based on the embodiments shown in the figures. However, the above are only preferred embodiments of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched by those skilled in the art to form a variety of equivalent solutions without departing from or changing the design concept and technical effects of the present invention. Therefore, the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A power generation control method for range-extended electric vehicles under different power generation scenarios, characterized in that, The power generation scenarios include at least one of the following: driver driving demand scenario, power battery SOC compensation scenario, power battery insufficient power scenario, engine ignition condition scenario, and external demand scenario. Driving scenario: When the SOC of the power battery is lower than a preset first threshold, or when the SOC is lower than a preset second threshold and the vehicle speed is higher than the corresponding set threshold, the range extender is controlled to start and obtain the first power; wherein the second threshold is greater than the first threshold; Power battery SOC compensation scenario: When the power battery SOC is less than a predetermined SOC threshold, the range extender is activated and a second power is acquired for battery recharging. The second power is positively correlated with the SOC deviation and the battery charging capacity. The battery charging capacity is defined as: battery charging power limit - motor recovery power. Insufficient power battery: When the SOC is greater than the second threshold and the vehicle is in pure electric mode, if the driver's power demand is greater than the power battery discharge power, the range extender will be activated and a third power source will be obtained as supplementary power. Engine ignition scenario: When the range extender starts for the first time, it generates electricity according to the preset fourth power. External demand scenario: When the range extender is started by external demand, if the SOC is less than the preset third threshold, the range extender will be controlled to generate electricity at the preset fifth power. Based on the power values ​​obtained from different scenarios, the range extender's power output is determined according to the current operating conditions, specifically including: If it is determined that the current condition is ignition-in operation, then only the fourth power is used as the range extender's power output; if it is determined that the current condition is not ignition-in operation, then the maximum value among the first power, the third power, and the fifth power is taken, and the maximum value is summed with the second power and the current high-voltage load demand power as the range extender's power output.

2. The power generation control method for range-extended vehicles under different power generation scenarios according to claim 1, characterized in that, Calculate the first power using the following formula: P1= ， Where P1 is the first power, N is the driver's torque requirement, T is the current drive motor speed, and Eff is the range extender system efficiency.

3. The power generation control method for range-extended vehicles under different power generation scenarios according to claim 1, characterized in that, The SOC deviation = target SOC - actual SOC.

4. The power generation control method for range-extended vehicles under different power generation scenarios according to claim 1, characterized in that, The third power is equal to the driver's required power minus the power battery's discharge power.

5. The power generation control method for range-extended vehicles under different power generation scenarios according to claim 1, characterized in that, In external demand scenarios, if the SOC is greater than the third threshold, the range extender is controlled to enter an idle state.

6. The power generation control method for range-extended vehicles under different power generation scenarios according to any one of claims 1 to 5, characterized in that, After obtaining the power output of the range extender, the target speed of the range extender is determined by querying a power-speed mapping table pre-calibrated based on the economic operating curve, and the target torque of the range extender is calculated based on the target speed.

Images