阅读说明：本技术 电驱动系统的降功率方法、装置、电驱动系统及车辆 (Power reduction method and device for electric drive system, electric drive system and vehicle ) 是由 李庆国 陈士刚 杭孟荀 刘琳 姚学松 张�杰 沙文瀚 刘靓 于 2021-01-25 设计创作，主要内容包括：本申请公开了一种电驱动系统的降功率方法、装置、电驱动系统及车辆,其中,方法包括：检测直流母线侧的实际电池电压；基于实际电池电压查询电压-输出功率间的关系表,得到电驱动系统的实际最大输出功率；根据实际最大输出功率计算与初始最大输出功率间的降值,并根据降值修改初始最大输出功率,确定当前最大输出功率。由此,解决了相关技术中不能发挥出驱动系统的最佳性能,造成了资源的浪费的问题,在降功率区间采用线性差值的方法进行降功率,实现在电池电压全范围段的精确控制,能够最大利用电驱动系统功率,大大提高电驱系统性能和整车动力性。(The application discloses a power reduction method and device of an electric drive system, the electric drive system and a vehicle, wherein the method comprises the following steps: detecting the actual battery voltage on the direct current bus side; inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; and calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power. Therefore, the problem that the best performance of a driving system cannot be exerted and resource waste is caused in the related technology is solved, power is reduced by adopting a linear difference method in a power reduction interval, accurate control in the full range of the battery voltage is realized, the power of an electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic performance of the whole vehicle are greatly improved.)

1. A method of derating an electric drive system, comprising the steps of:

detecting the actual battery voltage on the direct current bus side;

inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; and

and calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power.

2. The method of claim 1, further comprising:

the method comprises the steps of obtaining the current opening degree of an accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling a driving motor to output the target torque based on the torque instruction.

3. The method of claim 2, wherein generating a current torque command based on the current opening and the current maximum output power comprises:

acquiring the current rotating speed of the driving motor;

calculating to obtain a target torque according to the current rotating speed and the current maximum output power;

generating the current torque command according to the target torque.

4. The method of claim 3, wherein the target torque is calculated by the formula:

wherein P is the current maximum output power, T is the target torque, and n is the current rotational speed of the drive motor.

5. A power reduction device for an electric drive system, comprising:

the detection module is used for detecting the actual battery voltage on the direct current bus side;

the acquisition module is used for inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; and

and the power reducing module is used for calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value and determining the current maximum output power.

6. The apparatus of claim 5, further comprising:

and the control module is used for acquiring the current opening degree of an accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling a driving motor to output the target torque based on the torque instruction.

7. The apparatus of claim 6, wherein the control module comprises:

the acquisition unit is used for acquiring the current rotating speed of the driving motor;

the calculating unit is used for calculating to obtain a target torque according to the current rotating speed and the current maximum output power;

a generating unit configured to generate the current torque command according to the target torque.

8. The apparatus of claim 3, wherein the target torque is calculated by the formula:

wherein P is the current maximum output power, T is the target torque, and n is the current rotational speed of the drive motor.

9. An electric drive system, comprising: method for power reduction of an electric drive system according to any of claims 5-8.

10. A vehicle, characterized by comprising: the electric drive system of claim 9.

Technical Field

The application relates to the technical field of vehicles, in particular to a power reduction method and device for an electric drive system, the electric drive system and a vehicle.

Background

The new energy automobile is fast accelerated all the time, and the market reservation quantity is continuously increased. At present, an energy storage structure for a new energy automobile is mainly a power battery, the voltage of the battery can also change due to the difference of the electric quantity of the power battery, and the output power of an electric drive system is directly related to the voltage of a direct current bus, and the voltage of the vehicle is gradually reduced due to the reduction of the electric quantity of the whole vehicle in the driving process, so that the relation of the output power of the electric drive system corresponding to different voltages needs to be considered.

In the related art, the full-power operating voltage and the reduced-power operating voltage point of the electric drive system are generally determined according to the operating voltage range of the power battery, and then the output power in the whole reduced-power voltage operating area is taken as the maximum output power according to the peak power multiplied by a fixed coefficient (less than 1).

However, this method has a problem that the optimal performance of the driving system cannot be achieved, which causes a waste of resources and is in urgent need to be solved.

Content of application

The application provides a power reduction method and device of an electric drive system, the electric drive system and a vehicle, and aims to solve the problem that the best performance of the drive system cannot be exerted and resource waste is caused in the related technology.

An embodiment of the first aspect of the present application provides a power reduction method for an electric drive system, including the following steps:

detecting the actual battery voltage on the direct current bus side;

inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; and

and calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power.

Optionally, the power reduction method of the electric drive system further includes:

the method comprises the steps of obtaining the current opening degree of an accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling a driving motor to output the target torque based on the torque instruction.

Optionally, the generating a current torque command based on the current opening degree and the current maximum output power comprises:

acquiring the current rotating speed of the driving motor;

calculating to obtain a target torque according to the current rotating speed and the current maximum output power;

generating the current torque command according to the target torque.

Alternatively, the target torque is calculated by the following formula:

wherein P is the current maximum output power, T is the target torque, and n is the current rotational speed of the drive motor.

An embodiment of a second aspect of the present application provides a power reduction device of an electric drive system, including:

the detection module is used for detecting the actual battery voltage on the direct current bus side;

the acquisition module is used for inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; and

and the power reducing module is used for calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value and determining the current maximum output power.

Optionally, the power reducing device of the electric drive system further includes:

and the control module is used for acquiring the current opening degree of an accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling a driving motor to output the target torque based on the torque instruction.

Optionally, the control module includes:

the acquisition unit is used for acquiring the current rotating speed of the driving motor;

the calculating unit is used for calculating to obtain a target torque according to the current rotating speed and the current maximum output power;

a generating unit configured to generate the current torque command according to the target torque.

Alternatively, the target torque is calculated by the following formula:

wherein P is the current maximum output power, T is the target torque, and n is the current rotational speed of the drive motor.

Embodiments of a third aspect of the present application provide an electric drive system, which includes the power reduction device of the electric drive system.

An embodiment of a fourth aspect of the present application provides a vehicle comprising the electric drive system described above.

Thereby, the actual battery voltage on the dc bus side can be detected; inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; the method comprises the steps of calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power, so that the problem that the optimal performance of a driving system cannot be exerted and resources are wasted in the related art is solved, the power is reduced by adopting a linear difference method in a power reduction interval, the accurate control in the full range of the voltage of a battery is realized, the power of an electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic property of the whole vehicle are greatly improved.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart illustrating a power reduction method for an electric drive system according to an embodiment of the present disclosure;

FIG. 2 is an exemplary graph of an external characteristic of an electric drive system at different voltages according to one embodiment of the present application;

FIG. 3 is an exemplary graph of an external characteristic of an electric drive system at different voltages in accordance with another embodiment of the present application;

FIG. 4 is a flow chart of a power derating method of an electric drive system according to one embodiment of the present application;

FIG. 5 is a block diagram illustration of a power reduction device of an electric drive system according to an embodiment of the present application;

FIG. 6 is a block diagram illustration of an electric drive system according to an embodiment of the present application;

FIG. 7 is a block diagram illustration of a vehicle according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

The following describes a power reduction method and device of an electric drive system, the electric drive system and a vehicle according to an embodiment of the present application with reference to the drawings. In order to solve the problem that the related art mentioned in the background art center cannot exert the optimal performance of the driving system and cause the waste of resources, the application provides a power reduction method of an electric driving system, wherein the actual battery voltage on the direct current bus side can be detected; inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; the method comprises the steps of calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power, so that the problem that the optimal performance of a driving system cannot be exerted and resources are wasted in the related art is solved, the power is reduced by adopting a linear difference method in a power reduction interval, the accurate control in the full range of the voltage of a battery is realized, the power of an electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic property of the whole vehicle are greatly improved.

Specifically, fig. 1 is a schematic flow chart of a power reducing method of an electric drive system according to an embodiment of the present disclosure.

As shown in fig. 1, the power reduction method of the electric drive system includes the steps of:

in step S101, the actual battery voltage on the dc bus side is detected.

It can be understood that after the key of the driver is powered on, the relay is closed, the high voltage is applied to the whole vehicle, and the actual battery voltage on the direct current bus side can be detected by the driving motor controller in the embodiment of the application.

It should be noted that the above-mentioned manner for detecting the actual battery voltage at the dc bus side is only exemplary, and is not meant to limit the present invention, and a person skilled in the art may select an appropriate method to detect the actual battery voltage at the dc bus side according to actual situations, and details are not described herein to avoid redundancy.

In step S102, the actual maximum output power of the electric drive system is obtained by looking up the relationship table between voltage and output power based on the actual battery voltage.

It can be understood that the highest battery voltage on the dc bus side is assumed to be U₁Reduced power voltage value of U₂Minimum operating voltage of U₃Then determine U by bench test of the electric drive system₁、U₂、U₃Do a large output power, generally U₁And U₂Maximum peak power is the same, U₂、U₃And determining the maximum output power through a difference algorithm.

Specifically, as shown in fig. 2 and 3, fig. 2 and 3 are schematic diagrams of output power of the electric drive system at different voltages, where a is a line 1, B is a line 2, C is a line 3, D is a line 4, the lines 1 and 3 are torque curves, the lines 2 and 4 are power curves, and the main steps are as follows:

(1) testing an external characteristic curve above the full-power working voltage on the electric drive system rack;

(2) testing an external characteristic curve of a lowest working voltage point on a bench of the electric drive system;

(3) the external characteristic between the full power minimum voltage point and the minimum voltage point is obtained by a linear difference method.

In this embodiment of the present application, after the actual battery voltage on the dc bus side is obtained in step S101, the actual maximum output power of the electric drive system CAN be obtained by querying the voltage-output power relationship table, and the actual maximum output power is fed back to the vehicle Controller through a CAN (Controller Area Network) Network.

In step S103, a reduction value between the actual maximum output power and the initial maximum output power is calculated, the initial maximum output power is modified according to the reduction value, and the current maximum output power is determined.

It can be understood that, under the working condition of the whole vehicle, the voltage of the power battery is constantly changing, and therefore, the current maximum output power of the power battery also changes at any time, and according to the embodiment of the present application, the reduction value between the actual maximum output power and the initial maximum output power can be obtained according to the actual maximum output power and the initial maximum output power obtained in step S102, and the reduction value can be obtained by a linear interpolation method, so that the current maximum output power can be determined according to the reduction value.

Further, in some embodiments, the power reduction method of the electric drive system further includes: the method comprises the steps of obtaining the current opening degree of an accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling a driving motor to output a target torque based on the torque instruction.

It should be understood that the vehicle control unit according to the embodiment of the present application may determine the current maximum output power of the driving motor controller according to the accelerator request of the driver, the current opening degree of the accelerator pedal, and the current maximum output power fed back by the driving motor controller, and transmit the driving motor controller through the CAN network, so as to generate the current torque command according to the current maximum output power.

Wherein, in some embodiments, generating the current torque command based on the current opening and the current maximum output power comprises: acquiring the current rotating speed of a driving motor; calculating to obtain a target torque according to the current rotating speed and the current maximum output power; a current torque command is generated based on the target torque.

Alternatively, in some embodiments, the target torque is calculated by the following equation:

wherein, P is the current maximum output power, T is the target torque, and n is the current rotating speed of the driving motor.

It is understood that after generating the current torque command according to the target torque, the vehicle control unit may send the current torque command, and the electric drive system responds to the current torque command of the vehicle control unit, so that the driving motor controller controls the driving motor torque output through vector control.

In order to further understand the power reduction method of the electric drive system according to the embodiment of the present application, the following detailed description is provided with reference to fig. 4.

As shown in fig. 4, the power reduction method of the electric drive system includes the steps of:

s401, the key of the driver is powered on.

S402, the driving motor controller detects an actual battery voltage on the dc bus side.

And S403, the driving motor feeds back the maximum output power through the CAN network according to the actual battery voltage on the side of the direct current bus.

S404, the vehicle control unit requests the motor controller to output a target torque through the CAN network.

And S405, controlling the driving motor to output the target torque by the driving motor controller through controlling the three-phase current.

Therefore, in the running process of the electric automobile, the vehicle control unit communicates with the driving motor controller through the CAN network, and the driving motor controller controls the torque of the driving motor through controlling the current so as to achieve the running purposes of accelerating and decelerating of a driver and the like. The torque is controlled through a formula in the whole vehicle control processCalculating n is the rotating speed of the motor; the driving motor controller feeds back the maximum output power of the electric driving system in real time through the CAN signal, the whole vehicle controller requests torque within the range of the maximum output power, and the driving motor controller executes the torque request.

According to the power reduction method of the electric drive system, provided by the embodiment of the application, the actual battery voltage on the direct current bus side can be detected; inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; the method comprises the steps of calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power, so that the problem that the optimal performance of a driving system cannot be exerted and resources are wasted in the related art is solved, the power is reduced by adopting a linear difference method in a power reduction interval, the accurate control in the full range of the voltage of a battery is realized, the power of an electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic property of the whole vehicle are greatly improved.

Next, a power reduction device of an electric drive system proposed according to an embodiment of the present application is described with reference to the drawings.

FIG. 5 is a block schematic diagram of a power reduction device of an electric drive system of an embodiment of the present application.

As shown in fig. 5, the power reduction device 10 of the electric drive system includes: a detection module 100, an acquisition module 200, and a power down module 300.

The detection module 100 is configured to detect an actual battery voltage at a dc bus side;

the obtaining module 200 is configured to query a relation table between voltage and output power based on an actual battery voltage to obtain an actual maximum output power of the electric drive system; and

the power reduction module 300 is configured to calculate a reduction value between the actual maximum output power and the initial maximum output power, modify the initial maximum output power according to the reduction value, and determine the current maximum output power.

Optionally, in some embodiments, the power reducing device 10 of the electric drive system further includes:

and the control module is used for acquiring the current opening degree of the accelerator pedal, generating a current torque instruction based on the current opening degree and the current maximum output power, and controlling the driving motor to output the target torque based on the torque instruction.

Optionally, in some embodiments, the control module comprises:

the acquisition unit is used for acquiring the current rotating speed of the driving motor;

the calculating unit is used for calculating to obtain a target torque according to the current rotating speed and the current maximum output power;

and the generating unit is used for generating a current torque instruction according to the target torque.

Alternatively, in some embodiments, the target torque is calculated by the following equation:

wherein, P is the current maximum output power, T is the target torque, and n is the current rotating speed of the driving motor.

It should be noted that the foregoing explanation of the embodiment of the power reduction method of the electric drive system is also applicable to the power reduction device of the electric drive system of this embodiment, and details are not repeated here.

According to the power reduction device of the electric drive system provided by the embodiment of the application, the actual battery voltage on the direct current bus side can be detected; inquiring a relation table between voltage and output power based on the actual battery voltage to obtain the actual maximum output power of the electric drive system; the method comprises the steps of calculating a reduction value between the actual maximum output power and the initial maximum output power according to the actual maximum output power, modifying the initial maximum output power according to the reduction value, and determining the current maximum output power, so that the problem that the optimal performance of a driving system cannot be exerted and resources are wasted in the related art is solved, the power is reduced by adopting a linear difference method in a power reduction interval, the accurate control in the full range of the voltage of a battery is realized, the power of an electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic property of the whole vehicle are greatly improved.

As shown in fig. 6, the embodiment of the present application further provides an electric drive system 20, where the electric drive system 20 includes the power reduction device 10 of the electric drive system.

According to the electric drive system provided by the embodiment of the application, the problem that the best performance of the drive system cannot be exerted and resources are wasted in the related technology is solved through the power reducing device of the electric drive system, the power is reduced by adopting a linear difference method in a power reducing interval, the accurate control in the full range of the voltage of the battery is realized, the power of the electric drive system can be utilized to the maximum, and the performance of the electric drive system and the dynamic performance of the whole vehicle are greatly improved.

As shown in fig. 7, the embodiment of the present application further provides a vehicle 30, where the vehicle 30 includes the electric drive system 20 described above.

According to the vehicle provided by the embodiment of the application, the problem that the optimal performance of the driving system cannot be exerted and resources are wasted in the related technology is solved through the electric driving system, the power is reduced by adopting a linear difference method in a power reduction interval, the accurate control in the full range of the voltage of the battery is realized, the power of the electric driving system can be utilized to the maximum, and the performance of the electric driving system and the dynamic property of the whole vehicle are greatly improved.

In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "N" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more N executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of implementing the embodiments of the present application.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or N wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.