Power generation control method of extended-range automobile in different power generation scenes

Abstract

The invention discloses a power generation control method for an extended-range automobile in different power generation scenes, and the main design concept of the power generation control method is that a driver driving demand scene, a power battery SOC compensation scene, a power battery insufficient power scene, an engine ignition working condition scene, an external demand scene and other scenes are identified; and acquiring the corresponding power generation demand power, and arbitrating to obtain the range extender power generation power according to whether the current vehicle is in the light-off working condition or not. According to the method, various actual power generation scenes are identified, so that the range extender is automatically switched under the constant power and power following power generation working conditions, the SOC balance of the battery is conveniently controlled, the battery is prevented from being overcharged and overdischarged, and oil-electricity intelligent decision can be made by integrating various working conditions. Furthermore, the target torque working condition point of the range extender is obtained through the calculation result of the generated power of the range extender, the range extender is kept to operate in the relatively optimal working curve, and therefore the intelligence and economical efficiency of the range extending vehicle are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of range-extended vehicles, and particularly to a power generation control method for a range-extended vehicle under different power generation scenarios. Background Art

[0002] As an important branch of new energy, a series-connected range-extended electric vehicle (REEV) adds a range extender on the basis of a pure electric vehicle (EV) to increase the cruising range. The range extender couples an engine and a generator and decouples them from the wheels, and uses the engine to operate in the economic working area to save fuel. Due to its advantages such as relatively simple structure and control, good driving smoothness, and low usage cost, the market share of range-extended vehicles is increasing.

[0003] Generally, in the range-extended technology route, the power generation power control is divided into a constant power strategy and a multi-point strategy. The disadvantages of the technical solutions are mainly reflected in that with the change of working conditions, the current of the battery charging and discharging changes greatly, which is likely to cause 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 a range-extended vehicle under different power generation scenarios to solve the aforementioned technical problems.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a power generation control method for a range-extended vehicle under different power generation scenarios, where the power generation scenarios include at least one of the following: driver driving demand scenario, power battery SOC compensation scenario, power battery power shortage scenario, engine starting condition scenario, external demand scenario;

[0007] 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, control the range extender to start and obtain a first power;

[0008] Power battery SOC compensation scenario: When the SOC of the power battery is less than a given SOC threshold, control the range extender to start and obtain a second power for battery charging, where the second power is positively correlated with the SOC deviation and the battery charging ability;

[0009] Power battery power shortage scenario: When the SOC is greater than the second threshold and the vehicle is in pure electric mode, if the driver's demand power is greater than the power battery discharge power, control the range extender to start and obtain a third power as supplementary power;

[0010] Engine starting condition scenario: When the range extender starts for the first time, generate electricity at a preset fourth power;

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

[0012] Based on the power values obtained in different scenarios, make a decision on the power generation of the range extender according to the current working conditions, specifically including:

[0013] If it is determined that the current is in the ignition-on condition, only use the fourth power as the power generation power of the range extender; if it is determined that the current is in the non-ignition-on condition, take the maximum value among the first power, the third power, and the fifth power, and sum the maximum value with the second power and the demand power of the current high-voltage load as the power generation power of the range extender.

[0014] In at least one possible implementation, calculate the first power according to the following formula:

[0015] P 1 =

[0016] where P 1 is the first power, N is the driver torque demand, T is the current driving motor speed, and Eff is the range extender system efficiency.

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

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

[0019] In at least one possible implementation, in the external demand scenario, if the SOC is greater than the third threshold, control the range extender to enter the idle state.

[0020] In at least one possible implementation, after obtaining the power generation power of the range extender, query the power-speed mapping table pre-calibrated based on the economic working curve to determine the target speed of the range extender, and obtain the target torque of the range extender according to the target speed.

[0021] Compared with the prior art, the main design concept of the present invention lies in identifying multiple scenarios such as the driver's driving demand scenario, the power battery SOC compensation scenario, the power battery power shortage scenario, the engine ignition condition scenario, and the external demand scenario, obtaining the corresponding power generation demand, and arbitrating the power generation power of the range extender according to whether the current vehicle is in the ignition condition. By identifying a variety of actual power generation scenarios, the present invention enables the range extender to automatically switch between constant power and power-following power generation conditions, which not only facilitates controlling the battery SOC balance and preventing overcharging and over-discharging of the battery, but also can make intelligent decisions on fuel and electricity by integrating multiple working conditions. Further, the target torque working point of the range extender is obtained using the calculation result of the range extender power generation power, and the range extender is maintained to operate on a relatively optimal working curve, thereby significantly improving the intelligence and economy of the range-extended vehicle. Brief Description of the Drawings

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with the drawings, where:

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

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

[0025] The present invention proposes an embodiment of a power generation control method for a range-extended vehicle in different power generation scenarios. Specifically, it includes: the driver's driving demand scenario, the power battery SOC compensation scenario, the power battery power shortage scenario, the engine ignition condition scenario, and the external demand scenario;

[0026] For the driving scenario, when the power battery SOC is lower than a preset first threshold, or when the SOC is lower than a 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 a first power to meet the driver's driving demand. In this scenario, the driving power generation demand can be obtained as follows, that is, the first power P 1 .

[0027] Specifically, when controlling power generation based on the driver's driving demand, the driver's driving demand power, that is, P 1 The calculation method can be referred to as follows:

[0028] P 1 =

[0029] Among them, P 1 is the driver's driving demand power, N is the driver's torque demand, T is the current driving motor speed, and Eff is the range extender system efficiency.

[0030] For the power battery SOC compensation scenario, when the power battery SOC is lower than a lower level (which can be quantified according to the corresponding set threshold), the range extender is controlled to start and the second power for battery charging is obtained, where the second power is positively correlated with the SOC deviation (target SOC - actual SOC) and the battery charging ability (the battery charging power limit P Chrg - motor recovery power). In actual operation, the SOC compensation power generation power, that is, the second power P 2 .

[0031] Specifically, when performing power generation control based on the power battery SOC compensation, the power generation power P 2 for the range extender to compensate for SOC is positively correlated with the SOC deviation (target SOC - actual SOC) and the battery charging ability (the battery charging power limit P Chrg - motor recovery power), and can be obtained by looking up the following schematic pre-built two-dimensional table:

[0032]

[0033] For the power battery power shortage scenario, when the SOC is greater than the second threshold, the vehicle is in pure electric mode. If at this time the driver's demand power P is greater than the power battery discharge power P dischrg , then the range extender is controlled to start and the third power is obtained as supplementary power.

[0034] Specifically, when performing power generation control based on the power battery power shortage, the partial power supplemented by the range extender, that is, the third power P 3 = P - P Dischrg .

[0035] For the engine ignition condition 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 quickly bring the aftertreatment into working condition, the engine needs to work at a specific operating point for a period of time to rapidly increase the exhaust temperature and activate the catalytic converter to work. At this time, the power generation condition is to generate electricity according to a preset fourth power, that is, a fixed first constant power point P 4 .

[0036] For the external demand scenario, when the range extender is started by external demands (such as warm-up requests, air-conditioning heating, carbon canister desorption, etc.): If the SOC is greater than a preset third threshold, the range extender is controlled to enter the idle state, and the power generation power is 0 at this time; if the SOC is less than the preset third threshold, the range extender is controlled to enter the power generation state and generate power at a preset fifth power, that is, the established second constant power point P 5 。

[0037] Specifically, for the power generation control based on external demands, if there is no such driver-driven power generation demand as mentioned above, power generation is carried out in a fixed-point mode (preset constant value). At this time, power generation is only used to meet external demands, rather than providing power or charging the battery; here is a further expansion. For range-extended vehicles with a relatively small battery capacity of the power battery, fuel is usually the main power source. At this time, the heat source for heating the cockpit can use the engine coolant, and the range extender is started through an external request method to achieve control, so that the PTC device in the cockpit can be cancelled.

[0038] Combined with Figure 1 As shown, since the ignition power generation power has the highest priority, if it is determined that the current is in the ignition working condition, only the fourth power is used as the power generation power of the range extender; if it is determined that the current is in a non-ignition working condition and there are several power generation scenarios, for example, it also includes the required power of a high-voltage load (P 6 ), the following arbitration needs to be performed at this time: Take the maximum value of the first power, the third power, and the fifth power, sum it with the second power and the required power of the current high-voltage load, and use it as the power generation power of the range extender.

[0039] Finally, it can also be supplemented that after obtaining the above-mentioned power generation power of the range extender, the "power - speed" mapping table pre-calibrated based on the economic working curve can be queried to determine the speed of the range extender and calculate the target torque, as shown in the following table:

[0040]

[0041] After obtaining the target speed of the range extender by looking up the table, and then combining 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, that is, the operating power generation working condition point of the range extender is determined.

[0042] In summary, the main design concept of the present invention lies in identifying multiple scenarios such as the driver's driving demand scenario, the power battery SOC compensation scenario, the power battery power shortage scenario, the engine ignition condition scenario, and the external demand scenario, obtaining the corresponding power generation demand, and arbitrating the range extender power generation power according to whether the current vehicle is in the ignition condition. By identifying a variety of actual power generation scenarios, the present invention enables the range extender to automatically switch between constant power and power-following power generation conditions, which not only facilitates controlling the battery SOC balance and preventing overcharging and over-discharging of the battery, but also enables intelligent fuel-electric decision-making considering multiple working conditions. Further, the target torque operating point of the range extender is obtained using the calculation result of the range extender power generation power, and the range extender is maintained to operate on a relatively optimal working curve, thereby significantly improving the intelligence and economy of the range-extended vehicle.

[0043] In the embodiments of the present invention, if there are any expressions of directions, they are based on the relative concepts of the embodiments. In addition, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent the cases of A alone, A and B existing simultaneously, and B alone. Here, A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one of the following" and its similar expressions refer to any combination of these items, including any combination of single items 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 structure, features, and effects of the present invention have been described in detail based on the embodiments shown in the drawings above. However, the above are only the preferred embodiments of the present invention. It should be noted that for the technical features involved in the above embodiments and their preferred modes, those skilled in the art can reasonably combine and match them into multiple equivalent solutions without departing from and without changing the design concept and technical effects of the present invention. Therefore, the present invention is not limited by the scope shown in the drawings. Any changes made in accordance with the concept of the present invention or equivalent embodiments modified into equivalent changes still fall within the spirit covered by the description and the drawings, and should be within the protection scope of the present invention.

Claims

1. A power generation control method for a range-extended vehicle in different power generation scenarios, characterized in that: The power generation scenario includes at least one of the following: a driver driving demand scenario, a power battery SOC compensation scenario, a power battery power shortage scenario, an engine ignition condition scenario, and an external demand scenario; Driving scenario: When the power battery SOC is lower than the preset first threshold, or the SOC is lower than the preset second threshold and the vehicle speed is higher than the corresponding threshold, the range extender is controlled to start and obtain the first power; 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 the second power for battery charging, where the second power is positively correlated with the SOC deviation and the battery charging capacity; Insufficient power battery scenario: When the SOC is greater than the second threshold and the vehicle is in pure electric mode, if the driver's required power is greater than the power battery discharge power, the range extender is controlled to start and obtain the third power as supplementary power; Engine start-up condition scenario: When the range extender is started for the first time, it generates electricity at 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 is controlled to generate electricity according to the preset fifth power; Based on the power values ​​obtained in different scenarios, the range extender power generation is determined according to the current working conditions, including: If it is determined that the current working condition is in the ignition condition, only the fourth power is used as the power generation power of the range extender; if it is determined that the current working condition is in the non-ignition condition, the maximum value of the first power, the third power, and the fifth power is taken, and the maximum value is summed with the second power and the required power of the current high-voltage load as the power generation power of the range extender.

2. The power generation control method of the range-extended vehicle in different power generation scenarios according to claim 1 is characterized in that: The first power is calculated according to the following formula: P1= ， Among them, P1 is the first power, N is the driver's torque demand, T is the current drive motor speed, and Eff is the range extender system efficiency.

3. The power generation control method of the range-extended vehicle in different power generation scenarios according to claim 1 is characterized in that: The SOC deviation=target SOC-actual SOC; the battery charging capacity=battery charging power limit-motor recovery power.

4. The power generation control method of the range-extended vehicle in different power generation scenarios according to claim 1 is characterized in that: The third power=driver required power-power of the power battery discharge.

5. The power generation control method of the range-extended vehicle in different power generation scenarios according to claim 1 is characterized in that: In an external demand scenario, 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 a range-extended vehicle in different power generation scenarios according to any one of claims 1 to 5, characterized in that: After the power generated by the range extender is obtained, the target speed of the range extender is determined by querying a power-speed mapping table pre-calibrated based on an economic working curve, and the target torque of the range extender is obtained according to the target speed.

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