CN113844249B

CN113844249B - Hybrid power system, hybrid power vehicle, control method of hybrid power vehicle and vehicle control unit

Info

Publication number: CN113844249B
Application number: CN202110251139.3A
Authority: CN
Inventors: 王春生; 王吉全; 许伯良; 陈志乐; 孟范杰
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2021-03-08
Filing date: 2021-03-08
Publication date: 2022-07-15
Anticipated expiration: 2041-03-08
Also published as: CN113844249A

Abstract

The invention discloses a hybrid power system, a hybrid power vehicle, a control method of the hybrid power vehicle and a vehicle control unit, wherein the system comprises: an engine; a drive motor; a generator; a power battery; the controller is configured to determine a power protection target SOC of the hybrid vehicle when a power protection function of the hybrid vehicle is started, acquire the SOC of the power battery, control the hybrid vehicle to enter a first series mode when a difference value between the power protection target SOC and the SOC of the power battery is larger than a first preset value, drive the generator to generate power through the engine, and continuously charge the power battery while supplying power to the driving motor. Therefore, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the user on managing the whole vehicle energy is improved.

Description

Hybrid power system, hybrid power vehicle, control method of hybrid power vehicle and vehicle control unit

Technical Field

The invention relates to the technical field of vehicles, in particular to a hybrid power system, a hybrid power vehicle, a control method of the hybrid power vehicle and a vehicle control unit.

Background

With the development and popularization of the dual-mode vehicle, more functions specific to the dual-mode vehicle are released, wherein one typical representative function is the operation of a State of Charge (SOC) balance point, namely the interaction function of the user target demand electric quantity and the vehicle. If the health state of the vehicle is simply represented by the SOC, in general, the higher the SOC is, the healthier the vehicle is, and the vehicle is reflected in the aspects of fast power response (fast reaction), strong continuous power (strong endurance), higher smoothness (fine movement) and the like, and the dual-mode vehicle brings a more general experience to users.

However, most current energy management designs for plug-in hybrid vehicles are based on the overall vehicle economy, and when the destination is likely to be reached, the SOC is consumed to a lower level, which contradicts the user's greater demand for power at the destination.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, a first object of the present invention is to provide a hybrid power system, which can meet the requirements of users on energy management from two dimensions, interact not only with the target power-conserving electric quantity, but also with the speed of reaching the target electric quantity, and improve the control experience of users in managing the energy of the entire vehicle.

A second object of the invention is to propose a hybrid vehicle.

A third object of the invention is to propose a control method of a hybrid vehicle.

A fourth object of the invention is to propose a computer-readable storage medium.

The fifth purpose of the invention is to provide a vehicle control unit.

In order to achieve the above object, an embodiment of the first aspect of the present invention provides a hybrid system, including: the engine is used for selectively outputting power to the wheel end; the driving motor is used for outputting power to the wheel end; the generator is connected with the engine to generate electricity under the driving of the engine; the power battery is used for supplying power to the driving motor and charging according to alternating current output by the generator or the driving motor; the controller is configured to determine a power protection target SOC of the hybrid vehicle when a power protection function of the hybrid vehicle is started, acquire the SOC of the power battery, and control the hybrid vehicle to enter a first series mode when a difference value between the power protection target SOC and the SOC of the power battery is larger than a first preset value, drive the generator through the engine to generate power, and continuously charge the power battery while supplying power to the driving motor.

According to the hybrid power system provided by the embodiment of the invention, when the power protection function of the hybrid power vehicle is started, the power protection target SOC of the hybrid power vehicle is determined, the SOC of the power battery is obtained, and when the difference value between the power protection target SOC and the SOC of the power battery is larger than the first preset value, the hybrid power vehicle is controlled to enter the first series mode, the engine drives the generator to generate electricity, and the power battery is continuously charged while the driving motor is supplied with electricity. Therefore, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of managing the whole vehicle energy by the user is improved.

In order to achieve the above object, an embodiment of a second aspect of the present invention provides a hybrid vehicle including the hybrid system described above.

According to the hybrid power vehicle provided by the embodiment of the invention, the requirements of users on energy management can be met from two dimensions through the hybrid power system, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of users on managing the energy of the whole vehicle is improved.

In order to achieve the above object, a third aspect of the present invention provides a control method for a hybrid vehicle, the hybrid vehicle including an engine for selectively outputting power to wheel ends, a driving motor for outputting power to the wheel ends, a generator connected to the engine for generating electricity under the driving of the engine, and a power battery for supplying power to the driving motor and charging the generator or the driving motor according to an alternating current output from the generator, the control method including: determining a power protection target SOC of the hybrid vehicle when a power protection function of the hybrid vehicle is started, and acquiring the SOC of a power battery; and when the difference value between the power-saving target SOC and the SOC of the power battery is larger than a first preset value, the hybrid vehicle is controlled to enter a first series mode, the generator is driven by the engine to generate power, and the power battery is continuously charged while the driving motor is supplied with power.

According to the control method of the hybrid vehicle, when the power protection function of the hybrid vehicle is started, the power protection target SOC of the hybrid vehicle is determined, the SOC of the power battery is obtained, when the difference value between the power protection target SOC and the SOC of the power battery is larger than the first preset value, the hybrid vehicle is controlled to enter the first series mode, the generator is driven by the engine to generate electricity, and the power battery is continuously charged while the driving motor is powered. Therefore, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the user on managing the whole vehicle energy is improved.

To achieve the above object, a fourth aspect embodiment of the invention proposes a computer-readable storage medium on which a control program of a hybrid vehicle is stored, the control program of the hybrid vehicle realizing the foregoing control method of the hybrid vehicle when executed by a processor.

According to the computer-readable storage medium of the embodiment of the invention, through the control method of the hybrid electric vehicle, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the user on managing the energy of the whole vehicle is improved.

In order to achieve the above object, a fifth aspect of the present invention provides a vehicle control unit, which includes a memory, a processor, and a control program of a hybrid vehicle stored in the memory and capable of running on the processor, wherein when the processor executes the control program of the hybrid vehicle, the control method of the hybrid vehicle is implemented.

According to the vehicle control unit provided by the embodiment of the invention, through the control method of the hybrid vehicle, the requirement of a user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the user on managing the vehicle energy is improved.

Additional aspects and advantages of the invention 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 invention.

Drawings

FIG. 1a is a schematic illustration of a hybrid powertrain system according to a first embodiment of the present invention;

FIG. 1b is a schematic illustration of a hybrid powertrain system according to a second embodiment of the present invention;

FIG. 2 is a schematic diagram of a series power generation economic line according to one embodiment of the present invention;

FIG. 3 is a schematic diagram of series-connected generator speed limit according to one embodiment of the present invention;

FIG. 4 is a schematic of a series power generation constant power according to one embodiment of the present invention;

FIG. 5 is a schematic diagram of charging power of a power battery according to an embodiment of the invention;

FIGS. 6A-6B are schematic diagrams of mode switching according to one embodiment of the present invention;

FIG. 7 is a schematic illustration of an engine direct drive economy line according to one embodiment of the invention;

fig. 8 is a control flowchart of the hybrid system according to the first embodiment of the invention;

fig. 9 is a schematic configuration diagram of a hybrid system according to a third embodiment of the invention;

fig. 10 is a schematic diagram of a hybrid vehicle according to an embodiment of the invention;

fig. 11 is a flowchart of a control method of a hybrid vehicle according to an embodiment of the invention;

fig. 12 is a schematic diagram of a vehicle control unit according to an embodiment of the invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, 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 accompanying drawings are illustrative and intended to explain the present invention and should not be construed as limiting the present invention.

The hybrid system, the hybrid vehicle, the control method thereof, and the vehicle control unit according to the embodiments of the present invention will be described below with reference to the drawings.

Fig. 1a is a schematic configuration diagram of a hybrid system according to an embodiment of the present invention. Referring to fig. 1a, the hybrid system may include: the system comprises an engine 10, a driving motor 20, a generator 30, a power battery 40 and a controller 50.

The engine 10 is configured to selectively output power to the wheel end. The driving motor 20 is used for outputting power to the wheel end. The generator 30 is connected to the engine 10 to generate electricity by the engine 10. The power battery 40 is used to supply power to the driving motor 20 and to be charged according to the alternating current output from the generator 30 or the driving motor 20. The controller 50 is configured to determine a power conservation target SOC of the hybrid vehicle when a power conservation function of the hybrid vehicle is on, and acquire the SOC of the power battery 40, and control the hybrid vehicle to enter a first series mode when a difference between the power conservation target SOC and the SOC of the power battery 40 is greater than a first preset value, drive the generator 30 by the engine 10 to generate electricity, and continuously charge the power battery 40 while supplying power to the driving motor 20.

Specifically, the engine 10 may be an atkinson cycle engine, a clutch C1 is disposed between the engine 10 and the wheel end, and the controller 50 controls the connection and disconnection of the engine 10 and the wheel end by controlling the separation and connection of the clutch C1, so that the engine 10 can selectively output power to the wheel end, which may realize that the engine 10 directly drives, i.e., directly outputs power from the engine 10 to the wheel end. For example, when the controller 50 controls the clutch C1 to be disengaged, the engine 10 is disconnected from the wheel end, and the engine 10 does not directly output power to the wheel end, whereas when the controller 50 controls the clutch C1 to be engaged, the engine 10 is connected to the wheel end, and the engine 10 directly outputs power to the wheel end, so that the direct drive of the engine 10 is realized. Compared with the traditional pure extended range type hybrid electric vehicle, the structure has an engine direct-drive path, so that the energy conversion loss caused by the fact that the traditional pure extended range type hybrid electric vehicle is short of the engine direct-drive path and the engine is only capable of generating power through the generator and then providing the power to the driving motor to drive even if the engine is very efficient (the rotating speed and the torque of the engine are both efficient), and the energy conversion loss is further caused by the fact that the power battery can frequently work in a charging and discharging state, and the economical efficiency of the whole vehicle is effectively improved.

The driving motor 20 can be a flat wire motor, a stator winding of the flat wire motor adopts a rectangular coil, the slot filling rate of a stator slot is improved, the size of the motor is reduced, the power density of the motor is greatly improved, the driving motor 20 is directly connected with a wheel end through a gear, and the controller 50 controls the driving motor 20 to work to output power to the wheel end. Optionally, the motor shafts of the driving motor 20 and the generator 30 are arranged in parallel, and compared with other arrangement modes, such as coaxial arrangement of the driving motor 20 and the generator 30, the parallel arrangement mode of the embodiment has low requirement on the design of the motor, so that the high-power generator is easier to arrange and has low cost.

The generator 30 may be a flat wire motor, the generator 30 is connected between the clutch C1 and the engine 10, the generator 30 is directly connected to the engine 10 through a gear, the controller 50 may drive the generator 30 to generate electricity by controlling the engine 10 to work, and the generated electricity may be controlled by the controller 50 to charge the power battery 40 or supply power to the driving motor 20.

Alternatively, as shown with reference to FIG. 1a, the hybrid powertrain may also include a transmission 70 and a final drive 80. Referring to fig. 1b, the transmission 70 may further include gears Z1, Z2, Z3, and Z4, wherein a central shaft of the gear Z1 is connected to one end of the clutch C1, the gear Z1 is engaged with the gear Z2, the gear Z2 is engaged with the gear Z3, a central shaft of the gear Z3 is connected to the driving motor 20, a central shaft of the gear Z2 is connected to a central shaft of the gear Z4, and the gear Z4 is engaged with a main reduction gear of the main reduction gear 80. Of course, the transmission 70 may take other configurations as well, and is not limited thereto.

The power battery 40 may be a blade battery, the power battery 40 is electrically connected to the driving motor 20 and the generator 30, respectively, and under the control of the controller 50, the power battery 40 may supply power to the driving motor 20, or convert the ac power output by the generator 30 or the driving motor 20 into dc power and then charge the power battery 40, that is, the power battery 40 may be charged by the generator 30 or the driving motor 20.

The controller 50 is connected to the engine 10, the driving motor 20, the generator 30, the power battery 40 and the clutch C1, and the controller 50 can send control signals to the engine 10, the driving motor 20, the generator 30, the power battery 40 and the clutch C1 to control the engine 10, the driving motor 20, the generator 30, the power battery 40 and the clutch C1.

The controller 50 determines whether the power conservation function of the hybrid vehicle is turned on, for example, a power conservation function key such as SAVE key is provided on the vehicle, and when a user has a power conservation requirement (for example, the user has a clear target power conservation requirement which may be used for supplying power to the hybrid vehicle as a mobile energy storage power station after the hybrid vehicle arrives at a destination, etc.), the key can be pressed, and then the controller 50 determines that the power conservation function of the hybrid vehicle is turned on; for another example, the vehicle may automatically determine whether to start the power conservation function according to actual conditions (e.g., determine a congestion condition with a predictable long distance ahead through a map or navigation information, ensure that the vehicle travels in an EV mode on a congested road section ahead, etc.). That is, the power conservation function can be started manually or automatically.

When the power conservation function of the hybrid vehicle is turned on, which indicates that the SOC of the power battery needs to be quickly adjusted to the power conservation target SOC, that is, there is a demand for quick power generation, the controller 50 determines the power conservation target SOC of the hybrid vehicle. The power-saving target SOC may be set by a user according to actual requirements, or may be determined by the vehicle according to actual conditions, for example, the vehicle is provided with a power-saving electric quantity setting port, through which the user may set a target power-saving electric quantity, and the controller 50 may determine the power-saving target SOC of the hybrid vehicle according to the target power-saving electric quantity set by the user; for another example, the vehicle may adjust the SOC balance point according to actual conditions and the like, where the SOC balance point is the power conservation target SOC, and exemplarily, when the vehicle determines a congestion condition with a predictable long distance ahead through a map or navigation information, to ensure that the vehicle travels in an EV mode on a congested road section ahead, and the like, the SOC balance point may be increased at this time, and the power conservation target SOC is the increased SOC balance point. Therefore, interaction of the target power conservation capacity is realized.

After determining the power conservation target SOC of the hybrid vehicle, the controller 50 obtains the SOC of the power battery 40, and determines whether a difference between the power conservation target SOC and the SOC of the power battery 40 is greater than a first preset value (for example, 10%), if so, it indicates that a difference between the SOC of the power battery 40 and the power conservation target SOC is large, at this time, the controller 50 controls the hybrid vehicle to enter a first series mode, which is also called a full-operating-condition series mode, in which the controller 50 controls the engine 10 to drive the generator 30 to generate electricity, and the generated electricity supplies electricity to the driving motor 20 to provide a required driving demand on one hand, and continuously charges the power battery 40 on the other hand, so that the SOC of the power battery 40 can rapidly reach the power conservation target SOC to meet the power conservation demand of a user.

It should be noted that, in the first series mode, the engine 10 always charges the power battery 40, the power battery 40 is only charged but not discharged, and the parallel mode is not entered at this time, because the power generation torque is limited by the external characteristic line of the engine 10 in parallel, the output torque of the engine when the engine works on the economy line is small, and the purpose of rapid power supplement cannot be achieved, and the series mode and the parallel mode are frequently switched, the loss is large, and the power conservation of the power battery is not facilitated, so when the difference between the SOC of the power battery 40 and the power conservation target SOC is large, the purpose of rapid power conservation can be achieved by controlling the hybrid vehicle to be in the first series mode.

Therefore, when the power preservation function of the hybrid electric vehicle is started, the power preservation target SOC of the hybrid electric vehicle is determined, the SOC of the power battery is obtained, the hybrid electric vehicle is controlled to enter a first series mode when the difference value between the power preservation target SOC and the SOC of the power battery is larger than a first preset value, the generator is driven by the engine to generate electricity, the power battery is continuously charged when the driving motor is powered, the requirements of a user on energy management can be met from two dimensions, not only can the target power preservation electric quantity interact, but also the speed of reaching the target electric quantity can interact, and the control experience of managing the whole vehicle energy by the user is improved.

In some embodiments of the present invention, when the hybrid vehicle is operated in the first series mode, the controller 50 is further configured to control the engine 10 to operate at the second economy line, and determine the second series generating restriction power based on the second economy line and the second rotation speed restriction curve of the engine 10, and determine the second constant power generating power based on the second constant power generating curve of the engine 10, and acquire the charging power of the power cell 40 and the drive demand power of the hybrid vehicle, and determine the series generating power of the engine 10 based on the second series generating restriction power, the second constant power generating power, the charging power of the power cell 40, and the drive demand power of the hybrid vehicle.

Further, the controller 50 is further configured to determine the sum of the charging power of the power cell 40 and the drive demand power of the hybrid vehicle, and determine a first larger value between the sum of the charging power of the power cell 40 and the drive demand power of the hybrid vehicle and the second constant-power generated power; and taking the smaller value between the first larger value and the second series power generation limiting power as the series power generation power of the engine.

The rotation speed limit curve is the maximum rotation speed curve that the engine 10 can allow in the entire vehicle speed range when NVH (Noise, Vibration, Harshness) is satisfied. The series power generation limit power refers to the maximum output power that is allowed in the full vehicle speed range when the engine 10 is operating on the economy line (the first economy line or the second economy line) and the NVH is satisfied. The constant power generation curve is a power curve in which the engine 10 drives the generator 30 to generate power constantly under the premise of comprehensively considering the driving power demand and the economic demand at each vehicle speed. The constant power generation power refers to the constant power generation power of the generator 30 that meets the requirements of various vehicle speeds. The series generated power refers to the generated power of the engine 10 driving the generator 30 in the series mode.

It should be noted that the economy line in the series mode of the engine 10 may include a plurality of economy lines, and in the example shown in fig. 2, two economy lines may be included, which are a first economy line and a second economy line, respectively, the first economy line and the second economy line are respectively an operation curve with the best efficiency and the second best efficiency in the full speed range of the engine 10, and the output torque of the engine 10 operating in the second economy line at the same speed is equal to or greater than the output torque of the engine 10 operating in the first economy line. The number of the speed limiting curves of the engine 10 may include a plurality of curves, and taking fig. 3 as an example, two curves may be included, which are a first speed limiting curve and a second speed limiting curve, respectively, and the speed corresponding to the first speed limiting curve of the engine 10 is less than or equal to the speed corresponding to the second speed limiting curve of the engine 10 at the same speed. The constant power generation curve of the engine 10 may include a plurality of curves, for example, as shown in fig. 4, two curves may be included, which are a first constant power generation curve and a second constant power generation curve, respectively, and the constant power generation corresponding to the first constant power generation curve of the engine 10 is smaller than the constant power generation corresponding to the second constant power generation curve of the engine 10 at the same vehicle speed.

Specifically, when the hybrid vehicle operates in the first series mode, the controller 50 controls the engine 10 to operate on the second economy line shown in fig. 2, and obtains the second series electric power generation limiting power P1_ C according to the second economy line and the second rotation speed limiting curve of the engine 10 shown in fig. 3, specifically, the rotation speed of the engine 10 may be determined from the second rotation speed limiting curve in fig. 3 according to the vehicle speed of the hybrid vehicle, the output torque of the engine may be determined from the second economy line in fig. 2 according to the rotation speed, and the second series electric power generation limiting power P1_ C of the engine 10 may be determined according to the rotation speed and the torque. Meanwhile, the second constant-power electrical generation power P2_ C is determined from the second constant-power electrical generation curve of the engine 10 shown in fig. 4, and specifically, the second constant-power electrical generation power P2_ C may be determined from the second constant-power electrical generation curve shown in fig. 4 according to the vehicle speed of the hybrid vehicle. Meanwhile, the driving required power P3 of the hybrid vehicle at this time is calculated according to the conditions of the accelerator and the vehicle speed, and the charging power P4 of the power battery 40 is obtained, specifically, the charging power P4 of the power battery 40 can be determined from the power generation curve of the power battery 40 shown in fig. 5 according to the vehicle speed of the hybrid vehicle (it should be noted that, as shown in fig. 5, the charging power of the power battery 40 is in an ascending trend along with the increase of the vehicle speed, so as to meet the charging speed of the power battery at a high speed as much as possible, and ensure the energy requirement of the power battery at the high speed). Finally, the series generated power of the engine 10, i.e., the series generated power min [ P1_ C, max (P2_ C, P3+ P4) ], is determined according to the second series generated limiting power P1_ C, the second constant power generated power P2_ C, the charging power P4 of the power battery 40 and the driving required power P3 of the hybrid vehicle, that is, to achieve the purpose of power conservation, the power of the series generated power first needs to satisfy P3, and the additional generated power, i.e., the charging power P4 of the power battery 40 is added, and when the power of P3+ P4 is smaller than the power of P2_ C, the constant power generation of P2_ C is performed to supplement the power while being limited to the series generated limiting power P1_ C. Therefore, the power of series power generation is higher, and the power-preserving capability of the whole vehicle is strong.

In some embodiments of the present invention, when the difference between the power conservation target SOC and the SOC of the power battery is greater than the second preset value and equal to or less than the first preset value, the controller 50 is further configured to acquire the vehicle speed and the wheel-end demand torque of the hybrid vehicle, and determine a first wheel-end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel-end torque threshold value at which the hybrid vehicle exits the parallel mode according to the SOC of the power battery 40 and the vehicle speed. When the vehicle speed is greater than or equal to a preset vehicle speed threshold value, and the wheel end required torque is greater than or equal to a first wheel end torque threshold value and less than or equal to a second wheel end torque threshold value, controlling the hybrid vehicle to enter a first parallel mode; and controlling the hybrid vehicle to enter a second series mode when the vehicle speed is less than a preset vehicle speed threshold, or when the vehicle speed is greater than or equal to the preset vehicle speed threshold and the wheel end required torque is less than a first wheel end torque threshold, or when the vehicle speed is greater than or equal to the preset vehicle speed threshold and the wheel end required torque is greater than a second wheel end torque threshold.

In some embodiments of the present invention, when the hybrid vehicle is operated in the second series mode, the controller 50 is further configured to control the engine 10 to operate in the second economy line, and determine the second series generated limiting power based on the second economy line and the second rotation speed limiting curve of the engine 10, and determine the second constant power generated power based on the second constant power generated curve of the engine 10, and obtain the drive demand power of the hybrid vehicle, wherein a second larger value between the drive demand power of the hybrid vehicle and the second constant power generated power is determined, and a smaller value between the second larger value and the second series generated limiting power is taken as the series generated power of the engine 10.

In some embodiments of the present invention, when the hybrid vehicle is operated in the first parallel mode, the controller 50 is further configured to control the engine 10 to operate in the second direct drive economy line if the wheel-end demand torque is equal to or less than a difference between the output torque when the engine 10 is operated in the first direct drive economy line and the first torque threshold value, so that the engine 10 charges the power battery 40 with the output surplus torque through the drive motor 20; if the wheel end required torque is larger than the difference between the output torque when the engine 10 works on the first direct-drive economy line and the first torque threshold value and is smaller than the difference between the output torque when the engine 10 works on the second direct-drive economy line and the second torque threshold value, controlling the engine 10 to work on the economy line in the last state; if the wheel end required torque is larger than or equal to the difference between the output torque when the engine 10 works on the second direct-drive economy line and the second torque threshold value, controlling the engine 10 to work on the third direct-drive economy line so that the engine 10 can charge the power battery 40 with the output redundant torque through the driving motor 20; the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is basically superposed with the outer characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

It should be noted that the operating region of the engine 10 includes an economy zone in which the engine is capable of operating at all times with high efficiency, and the economy zone may include a plurality of direct drive economy lines, with the engine operating specifically on the direct drive economy lines of the economy zone. Taking fig. 7 as an example, three direct-drive economic lines may be included, which are a first direct-drive economic line, a second direct-drive economic line and a third direct-drive economic line, respectively, where the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is substantially coincident with an external characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

Specifically, when the difference between the power conservation target SOC and the SOC of the power battery is greater than a second predetermined value (e.g., 5%) and less than or equal to a first predetermined value (e.g., 10%), it indicates that there is a certain difference between the SOC of the power battery 40 and the power conservation target SOC, and at this time, the controller 50 obtains the vehicle speed and the wheel end required torque of the hybrid vehicle, and determines, according to the SOC of the power battery 40 and the vehicle speed, a first wheel end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode by means of a table lookup, as shown in fig. 6B, where the first wheel end torque threshold value T1_ C is smaller than the output torque T4_ C when the engine 10 operates on the third direct-drive economy line, and the second wheel end torque threshold value T2_ C is equal to the output torque T4_ C when the engine 10 operates on the third direct-drive economy line (it can be understood that, when the SOC of the power battery 40 has a certain difference from the power conservation target SOC of the power battery, it is desirable to generate as much power as possible without making the overall vehicle economy too low, so the first and second wheel-end torque thresholds T1_ C and T2_ C may be determined with reference to the output torque T4_ C of the engine 10 operating in the third direct-drive economy line). As shown in fig. 6B, when the vehicle speed is equal to or higher than the preset vehicle speed threshold value, and the wheel end required torque is equal to or higher than the first wheel end torque threshold value T1_ C and equal to or lower than the second wheel end torque threshold value T2_ C, the hybrid vehicle is controlled to enter the first parallel mode; and when the vehicle speed is less than a preset vehicle speed threshold value, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is less than a first wheel end torque threshold value T1_ C, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is greater than a second wheel end torque threshold value T2_ C, controlling the hybrid vehicle to enter a second series mode. That is, when the difference between the power conservation target SOC and the SOC of the power battery is greater than the second preset value and equal to or less than the first preset value, the hybrid vehicle is prohibited from entering the EV mode, and is operated in the first parallel mode or the second series mode.

When the hybrid vehicle is operated in the second series mode, the controller 50 controls the engine 10 to operate on the second economy line shown in fig. 2, and determines a second series electric power generation limiting power P1_ C from the second economy line and the second rotation speed limiting curve of the engine 10 shown in fig. 3, and at the same time determines a second constant power electric power generation power P2_ C from the second constant power electric power generation curve of the engine 10 shown in fig. 4, and obtains a driving required power P3 of the hybrid vehicle, and finally determines the series electric power generation power of the engine 10, i.e., the series electric power generation power is min [ P1_ C, max (P2_ C, P3) ] from the second series electric power generation limiting power P1_ C, the second constant power electric power generation power P2_ C, and the driving required power P3 of the hybrid vehicle, that is to achieve the electric power conservation purpose, the series electric power generation power first needs to satisfy P3, when P3 is less than P2_ C, then P2_ C constant power generation is performed for power compensation while being limited by the series generation limit power P1_ C. Therefore, the power limit of the series power generation is widened to a certain extent, the constant power of the series power generation is higher, and the power-preserving capability of the whole vehicle is strong. It should be noted that in the second series mode, the power battery 40 is not operated, and the power battery 40 can be charged if the engine 10 has excess energy, and only in response to wheel-end demand if there is no excess energy.

When the hybrid vehicle is operated in the first parallel mode, if the wheel-end required torque is less than or equal to the difference between the output torque T4_ a (obtainable by table lookup) when the engine 10 is operated in the first direct-drive economy line shown in fig. 7 and the first torque threshold, the engine 10 is controlled to operate in the second direct-drive economy line so that the engine 10 charges the power battery 40 with the output surplus torque through the driving motor 20, that is, to meet the power generation requirement, the engine 10 may be operated in the second direct-drive economy line in advance instead of continuing to operate in the first direct-drive economy line, so that the surplus torque may be used for parallel power generation by the driving generator 30 or the driving motor 20, thereby facilitating rapid power conservation, wherein the power generation power of the driving motor 20 is higher than the power generation power of the generator 30, and the idle loss of the driving motor 20 is greater than the idle loss of the generator 30, therefore, the driving motor 20 is preferably used for generating power to achieve the purpose of fast power supplement. If the wheel-end required torque is greater than the difference between the output torque T4_ a when the engine 10 operates in the first direct-drive economy line shown in fig. 7 and the first torque threshold value and is less than the difference between the output torque T4_ B (obtainable by table lookup) when the engine 10 operates in the second direct-drive economy line and the second torque threshold value, the engine 10 is controlled to operate with the economy line in the last state, so that frequent switching of the operating line of the engine 10 can be avoided. If the wheel end demand torque is equal to or greater than the difference between the output torque T4_ B when the engine 10 is operating in the second direct drive economy line and the second torque threshold, the engine 10 is controlled to operate in the third direct-drive economy line so that the engine 10 charges the power battery 40 with the surplus torque output by the driving motor 20, that is, to meet the power generation requirement, the engine 10 can be operated in the third direct-drive economy line in advance, rather than continuing to operate in the second direct drive economy line, so that the excess torque can be used for parallel power generation by driving either the generator 30 or the motor 20, thereby facilitating rapid power conservation, the generated power of the driving motor 20 is higher than the generated power of the driving generator 30, and the idle loss of the driving motor 20 is greater than the idle loss of the generator 30, so the driving motor 20 is preferably used to generate power to achieve the purpose of fast power compensation. Therefore, the high-torque economical switching condition is advanced during parallel power generation, and the working time and probability of parallel high-torque are increased, so that the power retention capacity during parallel power generation in the first parallel mode is improved.

It should be noted that when the direct drive torque allocated to the engine 10 is smaller than the output torque of the economic line when the engine 10 operates in the economic zone, it is indicated that the direct drive non-high-efficiency zone of the engine 10 is entered, and at this time, the parallel mode exits, as shown in fig. 7, and when the direct drive torque allocated to the engine 10 is smaller than the output torque corresponding to the direct drive exit line, the parallel mode exits, so as to ensure that the engine is in the high-efficiency zone when the engine is in the operating state.

In some embodiments of the present invention, when the difference between the power conservation target SOC and the SOC of the power battery is greater than a third preset value and equal to or less than a second preset value, the controller 50 is further configured to obtain a vehicle speed and a wheel end demand torque of the hybrid vehicle, and determine a first wheel end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode according to the SOC of the power battery 40 and the vehicle speed when the vehicle speed is greater than or equal to a preset vehicle speed threshold value, wherein the hybrid vehicle is controlled to enter the second parallel mode when the wheel end demand torque is greater than or equal to the first wheel end torque threshold value and equal to or less than the second wheel end torque threshold value; controlling the hybrid vehicle to enter the EV mode when the wheel end required torque is smaller than a first wheel end torque threshold value; when the wheel end required torque is larger than a second wheel end torque threshold value, controlling the hybrid vehicle to enter a third series mode; and the third preset value is smaller than the second preset value, and the second preset value is smaller than the first preset value.

In some embodiments of the invention, when the vehicle speed is less than the preset vehicle speed threshold, the controller 50 is further configured to determine a third wheel end torque threshold at which the hybrid vehicle enters the series mode according to the SOC of the power battery 40 and the vehicle speed, wherein when the wheel end required torque is equal to or greater than the third wheel end torque threshold, the hybrid vehicle is controlled to enter the third series mode; and controlling the hybrid vehicle to enter the EV mode when the wheel end required torque is smaller than the third wheel end torque threshold value.

In some embodiments of the present invention, when the hybrid vehicle operates in the third series mode, the controller 50 is further configured to control the engine 10 to operate at the first economy line, and determine the first series generation limiting power from the first economy line and the first rotation speed limiting curve of the engine 10, and determine the first constant-power generation power from the first constant-power generation curve of the engine 10, and obtain the drive demand power of the hybrid vehicle, wherein a third value between the drive demand power of the hybrid vehicle and the first constant-power generation power is determined, and a smaller value between a third larger value and the first series generation limiting power is taken as the series generation power of the engine 10; the first economy line and the second economy line are the operating curves with the best efficiency and the second best efficiency in the full speed range of the engine 10, and the output torque of the engine 10 operating in the second economy line is equal to or greater than the output torque of the engine 10 operating in the first economy line at the same speed.

In some embodiments of the present invention, when the hybrid vehicle is operated in the second parallel mode, the controller 50 is further configured to control the engine 10 to operate in the second direct drive economy line if the wheel-end demand torque is equal to or less than a difference between the output torque when the engine 10 is operated in the first direct drive economy line and the third torque threshold value, so that the engine 10 charges the power battery 40 with the output surplus torque through the drive motor 20 or the generator 30; if the wheel end required torque is larger than the difference between the output torque of the engine 10 when the engine 10 works on the first direct-drive economic line and the third torque threshold value and is smaller than the difference between the output torque of the engine 10 when the engine 10 works on the second direct-drive economic line and the fourth torque threshold value, controlling the engine 10 to work on the corresponding direct-drive economic line according to the requirement of the engine 10; if the wheel end required torque is larger than or equal to the difference between the output torque of the engine working in the second direct-drive economy line and the fourth torque threshold value, controlling the engine 10 to work in the third direct-drive economy line, so that the engine 10 can charge the power battery 40 with the output redundant torque through the driving motor 20; the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is basically overlapped with an external characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

Specifically, when the difference between the power conservation target SOC and the SOC of the power battery is greater than a third preset value (e.g., -5%) and less than or equal to a second preset value (e.g., 5%), which indicates that the SOC of the power battery 40 is relatively close to the power conservation target SOC, the controller 50 obtains the vehicle speed and the wheel end required torque of the hybrid vehicle, and determines a first wheel end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode by looking up a table according to the SOC of the power battery 40 and the vehicle speed when the vehicle speed is greater than or equal to a preset vehicle speed threshold value, as shown in fig. 6A, the first wheel end torque threshold value T1_ a is smaller than the output torque T4_ B when the engine 10 operates in the second direct drive economy line, the second wheel end torque threshold value T2_ a is larger than the output torque T4_ B when the engine 10 operates in the second economy line (as can be understood, when the SOC of the power battery 40 is close to the power conservation target SOC, the economy is improved as much as possible while ensuring power generation, and therefore the first wheel end torque threshold value T1_ a and the second wheel end torque threshold value T2_ a may be determined with reference to the output torque T4_ B when the engine 10 operates in the second direct drive economy line. Also, as shown in fig. 6A, when the wheel end required torque is equal to or greater than the first wheel end torque threshold value T1_ a and equal to or less than the second wheel end torque threshold value T2_ a, the hybrid vehicle is controlled to enter the second parallel mode; controlling the hybrid vehicle to enter the EV mode when the wheel end required torque is smaller than a first wheel end torque threshold value T1_ A; when the wheel end required torque is greater than the second wheel end torque threshold T2_ a, the hybrid vehicle is controlled to enter the third series mode. When the vehicle speed is less than the preset vehicle speed threshold, the controller 50 determines a third wheel end torque threshold T3_ a of the hybrid vehicle entering the series mode through a table lookup according to the SOC of the power battery 40 and the vehicle speed, and controls the hybrid vehicle to enter the third series mode when the wheel end required torque is greater than or equal to the third wheel end torque threshold T3_ a, as shown in fig. 6A; and when the wheel end required torque is smaller than a third wheel end torque threshold value T3_ A, controlling the hybrid vehicle to enter the EV mode.

That is to say, when the vehicle speed is less than the preset vehicle speed threshold, the actual working mode is only the EV mode and the third series mode, the third wheel end torque threshold entering the third series mode is determined according to the SOC and the vehicle speed condition, if the wheel end required torque is less than the third wheel end torque threshold, the EV mode is entered, otherwise, the third series mode is entered. When the vehicle speed is greater than or equal to a preset vehicle speed threshold value, the actual working modes comprise an EV mode, a third series mode and a second parallel mode, a first wheel end torque threshold value entering the second parallel mode and a second wheel end torque threshold value exiting the parallel mode are judged according to the SOC and the vehicle speed condition, and if the wheel end required torque is smaller than the first wheel end torque threshold value, the EV mode is entered; if the wheel end required torque is larger than the second wheel end torque threshold value, entering a third series mode; and if the first wheel end torque threshold is smaller than or equal to the wheel end required torque and smaller than or equal to the second wheel end torque threshold, entering a second parallel mode. And in the second parallel mode state, if the wheel end required torque is larger than the output torque T4_ B of the engine working on the second direct-drive economic line, the engine works in the parallel power-assisted state, otherwise, the engine works in the parallel power generation state.

When the hybrid vehicle is operating in the EV mode, all of the wheel-end required torque is provided by the drive motor 20 driven by the power battery 40.

When the hybrid vehicle is operated in the third series mode, the controller 50 controls the engine 10 to operate at the first economy line shown in fig. 2, and determines a first series electric power generation limiting power P1_ a from the first economy line and the first rotation speed limiting curve of the engine 10 shown in fig. 3, and at the same time determines a first constant electric power generation power P2_ a from the first constant electric power generation curve of the engine 10 shown in fig. 4, and obtains a drive required power P3 of the hybrid vehicle, and finally determines a series electric power generation power of the engine 10 from the first series electric power generation limiting power P1_ a, the first constant electric power generation power P2_ a, and the drive required power P3 of the hybrid vehicle, that is, the series electric power generation power is set to min [ P1_ a, max (P2_ a, P3) ], that is, for the purpose of power conservation, the series electric power first needs to satisfy P3, when P3 is less than P2_ a, then P2_ a constant power generation is performed for power compensation while being limited by the series generated limit power P1_ a. Therefore, the power limitation of series power generation is relaxed to a certain extent, the constant power of the series power generation is higher, and the power-preserving capability of the whole vehicle is strong.

When the hybrid vehicle is operated in the second parallel mode, if the wheel-end required torque is less than or equal to the difference between the output torque T4_ a when the engine 10 is operated in the first direct-drive economic line and a third torque threshold (the third torque threshold is less than the first torque threshold), controlling the engine 10 to operate in the second direct-drive economic line, so that the engine 10 charges the power battery 40 with the output redundant torque through the driving motor 20 or the generator 30, that is, to meet the power generation requirement, the engine 10 can be operated in the second direct-drive economic line in advance, and the redundant torque is used for parallel power generation through the driving generator 30 or the driving motor 20; if the wheel-end required torque is greater than the difference between the output torque T4_ a and the third torque threshold when the engine 10 operates on the first direct-drive economic line and is less than the difference between the output torque T4_ B and the fourth torque threshold (the fourth torque threshold is less than the second torque threshold) when the engine 10 operates on the second direct-drive economic line, controlling the engine 10 to operate on the corresponding direct-drive economic line according to the requirement of the engine 10, for example, controlling the engine 10 to operate on the economic line in the previous state, so that frequent switching of the operating line of the engine 10 can be avoided; if the wheel end required torque is larger than or equal to the difference between the output torque T4_ B when the engine works in the second direct-drive economic line and the fourth torque threshold value, the engine 10 is controlled to work in the third direct-drive economic line, so that the engine 10 can charge the power battery 40 with the output redundant torque through the driving motor 20, namely, in order to meet the power generation requirement, the engine 10 can be operated in the third direct-drive economic line in advance, and the redundant torque is used for carrying out parallel power generation through the driving generator 30 or the driving motor 20. Therefore, the condition of high torque economy switching is advanced during parallel power generation, and the working time and probability of parallel high torque are increased, so that the power retention capacity during parallel power generation is improved.

In some embodiments of the present invention, the controller 50 is further configured to obtain driving parameters of the hybrid vehicle when a difference between the power-saving target SOC and the SOC of the power battery is less than or equal to a third preset value, and control the engine 10, the driving motor 20 and the generator 30 according to the driving parameters to operate the engine 10 in an economy zone by performing charge and discharge control on the power battery 40, and select an operation mode with the lowest equivalent as a current operation mode of the hybrid vehicle by comparing equivalent fuel consumptions of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel end required torque, the SOC of the power battery 40 and a vehicle speed of the hybrid vehicle.

In some embodiments of the present invention, the controller 50 is further configured to, when the power conservation function of the hybrid vehicle is not turned on, obtain driving parameters of the hybrid vehicle, and control the engine 10, the driving motor 20 and the generator 30 according to the driving parameters, so as to operate the engine 10 in an economic region by performing charge and discharge control on the power battery 40, and select an operating mode with the lowest equivalent fuel consumption as the current operating mode of the hybrid vehicle by comparing equivalent fuel consumptions of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel end demand torque, an SOC of the power battery and a vehicle speed of the hybrid vehicle.

That is, when the difference between the power conservation target SOC and the SOC of the power battery 40 is equal to or less than the first preset value or when the power conservation function of the hybrid vehicle is not turned on, it indicates that there is no demand for rapid power generation, and at this time, energy management is performed in accordance with the vehicle priority economy.

Specifically, the controller 50 obtains driving parameters of the hybrid vehicle, where the driving parameters may include at least one of a wheel end required torque, an SOC of the power battery 40, and a vehicle speed of the hybrid vehicle, and the controller 50 controls the engine 10, the driving motor 20, and the generator 30 according to the driving parameters to control charging and discharging of the power battery 40, so that the engine 10 operates in an economic area, and selects an operating mode with the lowest equivalent oil consumption as a current operating mode of the hybrid vehicle by comparing equivalent oil consumptions of the hybrid vehicle in a series mode, a parallel mode, and an EV mode. It should be noted that, when performing the equivalent fuel consumption comparison, the comparison is based on the comparison when the engine 10 operates in the economy zone, for example, the engine 10 operates in the economy zone at 25kW, but in combination with the driving parameters such as the wheel end demand torque, there is a possibility that the fuel consumption in the parallel mode is lower than the fuel consumption in the series mode and also lower than the fuel consumption in the EV mode, and at this time, the hybrid vehicle is controlled to operate in the parallel mode, and if the fuel consumption in the EV mode is lower than the fuel consumption in the parallel mode and also lower than the fuel consumption in the series mode, the hybrid vehicle is controlled to operate in the EV mode. The equivalent fuel consumption is the sum of the oil consumed by the engine 10 itself and the electrically equivalent oil consumed by the power battery 40, wherein the electric quantity consumed by the power battery 40 can be converted into oil according to an empirical value to obtain the electrically equivalent oil consumed by the power battery 40, the electrically equivalent oil consumed by the power battery 40 is a negative value when the power battery 40 is charged, and the electrically equivalent oil consumed by the power battery 40 is a positive value when the power battery 40 is discharged. That is to say, the controller 50 may comprehensively determine driving parameters of the hybrid vehicle, such as the wheel end required torque, the SOC of the power battery 40, the vehicle speed of the hybrid vehicle, and the equivalent fuel consumption of the hybrid vehicle in different operating modes, so that the hybrid vehicle is in the operating mode with the lowest equivalent fuel consumption under the condition of meeting the power requirement and NVH, and the hybrid vehicle has higher economy.

As a specific example, the controller 50 may be configured to control the hybrid vehicle according to the control logic shown in fig. 8, and may specifically include the following steps:

and step S101, whether the power protection function is started or not. If so, step S102 is performed, otherwise step S103 is performed.

Step S102, acquiring a power-maintaining target SOC and the SOC (current actual SOC) of the power battery.

And S103, controlling the whole vehicle according to an economic strategy without power protection requirements.

And step S104, whether the power-maintaining target SOC-SOC of the power battery is less than or equal to a third preset value is true. If yes, the process returns to step S103, otherwise, step S105 is executed.

And S105, judging whether the power retention target SOC-the SOC of the power battery is less than or equal to a second preset value. If so, step S106 is executed, otherwise, step S115 is executed.

Step S106, it is determined whether the hybrid vehicle is operated in the series mode according to fig. 6A. If so, step S107 is performed, otherwise step S108 is performed.

Step S107, the hybrid vehicle is controlled to operate in the third series mode, in which the engine is controlled to operate on the first direct-drive economy line, and the series generated power is min [ P1_ a, max (P2_ a, P3) ].

Step S108, it is determined whether the hybrid vehicle is operated in the parallel mode according to fig. 6A. If so, step S110 is performed, otherwise step S109 is performed.

In step S109, the hybrid vehicle is controlled to operate in the EV mode.

In step S110, T is not greater than T4_ a — Δ T3, that is, the wheel-end required torque T is not greater than the difference between the output torque T4_ a and the third torque threshold Δ T3 when the engine 10 operates in the first direct-drive economy line. If so, step S111 is performed, otherwise step S112 is performed.

And step S111, controlling the engine to work on a second direct-drive economic line, wherein the working torque is T4_ B.

And S112, judging whether T is more than or equal to T4_ B-delta T4, namely the wheel end required torque T is more than or equal to the difference between the output torque T4_ B and the fourth torque threshold delta T4 when the engine 10 works with the second direct-drive economy line. If so, step S113 is performed, otherwise step S114 is performed.

And step S113, controlling the engine to work in a third direct-drive economy line, wherein the working torque is T4_ C.

Step S114, the last state is maintained.

And S115, judging whether the power keeping target SOC-the SOC of the power battery is less than or equal to a first preset value. If so, step S117 is performed, otherwise step S116 is performed.

And step S116, controlling the hybrid vehicle to work in the first series mode, wherein the engine is controlled to work in the second direct-drive economic line, and the series power generation power is min [ P1_ C, max (P2_ C, P3+ P4) ].

Step S117 determines whether the hybrid vehicle is operated in the parallel mode according to fig. 6B. If so, step S119 is performed, otherwise step S118 is performed.

And step S118, controlling the hybrid vehicle to work in a second series mode, wherein the engine is controlled to work in a second direct-drive economic line, and the series power generation power is min [ P1_ C, max (P2_ C, P3) ].

And step S119, whether T is less than or equal to T4_ A-delta T1 is true, namely the wheel end required torque T is less than or equal to the difference between the output torque T4_ A and the first torque threshold delta T1 when the engine works in the first direct-drive economic line. If so, step S120 is performed, otherwise step S121 is performed.

And step S120, controlling the engine to work in a second direct-drive economic line, wherein the working torque is T4_ B.

In step S121, T ≧ T4_ B- Δ T2 is true, i.e., the wheel-end required torque T is greater than or equal to the difference between the output torque T4_ B when the engine 10 operates in the second direct-drive economy line and the second torque threshold Δ T2. If so, step S122 is performed, otherwise step S123 is performed.

And S122, controlling the engine to work in a third direct-drive economic line, wherein the working torque is T4_ C.

Step S123, the previous state is maintained.

Therefore, when the power protection requirement exists, the power generation speed is preferentially considered, the power is generated to the target electric quantity at a higher speed, and when the power protection requirement does not exist, the economy of the whole vehicle is preferentially considered, and the power is generated to the target electric quantity with the optimal efficiency as soon as possible.

In some embodiments of the present invention, the aforementioned hybrid power system further includes a dual electronic control module 60, where the dual electronic control module 60 is respectively connected to the driving motor 20 and the generator 30, and the dual electronic control module 60 supplies power to the driving motor 20 according to the ac power output by the generator; the power battery 40 is connected with the dual electronic control module 60, the power battery 40 supplies power to the driving motor 20 through the dual electronic control module 60, or is charged according to the alternating current output by the generator 30 or the driving motor 20 through the dual electronic control module 60, the dual electronic control module 60 comprises a first inverter 61, a second inverter 62 and a DC/DC63, the alternating current terminal of the first inverter 61 is connected to the driving motor 20, the direct current terminal of the first inverter 61 is respectively connected with the direct current terminal of the second inverter 62 and the first direct current terminal of the DC/DC63, the alternating current terminal of the second inverter 62 is connected to the generator 30, and the second direct current terminal of the DC/DC63 is connected to the power battery 40.

The operation of the dual electric control module 60 when the hybrid vehicle is in different operation modes will be described with reference to fig. 9. Specifically, when the power output between the engine 10 and the wheel end is cut off and the generator 10 is driven to generate electricity, the hybrid vehicle enters a series mode in which the alternating current output from the generator 30 is converted into direct current by the second inverter 62 and the direct current is converted into alternating current by the first inverter 61 and supplied to the driving motor 20, so that the driving motor 20 performs a driving operation; or the alternating current output by the generator 30 is converted into direct current by the second inverter 62 and converted into alternating current by the first inverter 61 to be supplied to the driving motor 20, and the direct current output by the power battery 40 is converted into alternating current by the first inverter 61 after being converted by the DC/DC63 to be supplied to the driving motor 20, so that the driving motor 20 can be driven; or the alternating current output by the generator 30 is converted into direct current by the second inverter 62, and the direct current is converted into alternating current by the first inverter 61 and is supplied to the driving motor 20, so that the driving motor 20 performs driving operation, and the direct current is converted by the DC/DC63 and is charged to the power battery 40.

When the engine 10 and the generator 30 are not operated and the power battery 40 supplies power to the driving motor 20, the hybrid vehicle enters an EV mode in which direct current output from the power battery 40 is converted into alternating current by the first inverter 61 to be supplied to the driving motor 20 after passing through the DC/DC63, so that the driving motor 20 performs a driving operation.

When the engine 10 is in power coupling with the wheel end, the generator 30 idles, and the engine 10 drives the driving motor 20 to generate power, the hybrid vehicle enters a parallel power generation mode, alternating current output by the driving motor 20 is converted into direct current through the first inverter 61, and the direct current is converted through the DC/DC to charge the power battery 40; alternatively, when the engine 10 is power-coupled to the wheel end and the driving motor 20 is idling, and the engine 10 drives the generator 30 to generate power, the hybrid vehicle enters a parallel power generation mode, and ac power output from the generator 30 is converted into DC power by the second inverter 62, and the DC power is converted by the DC/DC converter to charge the power battery 40. When the engine 10 is power-coupled to the wheel ends, the generator 30 is idling, and the power battery 40 supplies power to the driving motor 20, the hybrid vehicle enters a parallel boost mode in which the direct current output from the power battery 40 is converted by the DC/DC63 and then converted into alternating current by the first inverter 61 to be supplied to the driving motor 20, so that the driving motor 20 performs driving operation, and simultaneously the engine 10 outputs power to the wheel ends so as to participate in driving operation. Therefore, the hybrid electric vehicle can work in different modes through the double electric control modules.

According to the hybrid power system provided by the embodiment of the invention, when the power protection function of the hybrid power vehicle is started, the power protection target SOC of the hybrid power vehicle is determined, the SOC of the power battery is obtained, and when the difference value between the power protection target SOC and the SOC of the power battery is greater than the first preset value, the hybrid power vehicle is controlled to enter the first series mode, the engine drives the generator to generate power, and the power battery is continuously charged while the driving motor is supplied with power. Therefore, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of managing the whole vehicle energy by the user is improved.

Fig. 10 is a schematic structural diagram of a hybrid vehicle according to an embodiment of the present invention, and referring to fig. 10, the hybrid vehicle 1000 includes the hybrid system 100 described above.

According to the hybrid power vehicle disclosed by the embodiment of the invention, the requirements of users on energy management can be met from two dimensions through the hybrid power system, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the users on managing the energy of the whole vehicle is improved.

Fig. 11 is a flowchart of a control method of a hybrid vehicle according to an embodiment of the invention. As shown in fig. 1a, the hybrid vehicle includes an engine for selectively outputting power to a wheel end, a driving motor for outputting power to the wheel end, a generator connected to the engine for generating power under the driving of the engine, and a power battery for supplying power to the driving motor and charging according to ac power output from the generator or the driving motor.

Referring to fig. 11, the control method of the hybrid vehicle includes:

step S201, when the power protection function of the hybrid vehicle is started, the power protection target SOC of the hybrid vehicle is determined, and the SOC of the power battery is obtained.

And S202, when the difference value between the power-saving target SOC and the SOC of the power battery is larger than a first preset value, controlling the hybrid vehicle to enter a first series mode, driving a generator to generate power through an engine, and continuously charging the power battery while supplying power to a driving motor.

In some embodiments of the present invention, when the hybrid vehicle is operated in the first series mode, the engine is controlled to operate in the second economy line, and the second series generated limiting power is determined based on the second economy line and the second rotation speed limiting curve of the engine, and the second constant power generated power is determined based on the second constant power generating curve of the engine, and the charging power of the power battery and the driving demand power of the hybrid vehicle are acquired, and the series generated power of the engine is determined based on the second series generated limiting power, the second constant power generated power, the charging power of the power battery, and the driving demand power of the hybrid vehicle.

In some embodiments of the present invention, determining the series generated power of the engine from the second series generated limit power, the second constant-power generated power, the charging power of the power battery, and the driving demand power of the hybrid vehicle includes: determining the sum of the charging power of the power battery and the driving demand power of the hybrid vehicle, and determining a first larger value between the sum of the charging power of the power battery and the driving demand power of the hybrid vehicle and the second constant power generation power; and taking the smaller value between the first larger value and the second series power generation limiting power as the series power generation power of the engine.

In some embodiments of the invention, when the difference between the power-saving target SOC and the SOC of the power battery is greater than a second preset value and less than or equal to a first preset value, the vehicle speed and the wheel end required torque of the hybrid vehicle are also obtained, and a first wheel end torque threshold value when the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value when the hybrid vehicle exits the parallel mode are determined according to the SOC of the power battery and the vehicle speed, wherein when the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is greater than or equal to the first wheel end torque threshold value and less than or equal to the second wheel end torque threshold value, the hybrid vehicle is controlled to enter the first parallel mode; and when the vehicle speed is less than a preset vehicle speed threshold value, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is less than a first wheel end torque threshold value, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is greater than a second wheel end torque threshold value, controlling the hybrid vehicle to enter a second series mode.

In some embodiments of the present invention, when the hybrid vehicle operates in the second series mode, the engine is controlled to operate at the second economy line, and the second series generated limiting power is determined based on the second economy line and the second rotational speed limiting curve of the engine, and the second constant power generated power is determined based on the second constant power generated curve of the engine, and the driving demand power of the hybrid vehicle is obtained, wherein a second larger value between the driving demand power of the hybrid vehicle and the second constant power generated power is determined, and a smaller value between the second larger value and the second series generated limiting power is taken as the series generated power of the engine.

In some embodiments of the present invention, when the hybrid vehicle is operated in the first parallel mode, if the wheel-end demand torque is less than or equal to a difference between an output torque when the engine is operated in the first direct-drive economy line and a first torque threshold value, the engine is controlled to operate in the second direct-drive economy line so that the engine charges the power battery with an output surplus torque through the driving motor; if the wheel end required torque is larger than the difference between the output torque of the engine when the engine works in the first direct-drive economic line and the first torque threshold value and is smaller than the difference between the output torque of the engine when the engine works in the second direct-drive economic line and the second torque threshold value, controlling the engine to work in the economic line in the last state; if the wheel end required torque is larger than or equal to the difference between the output torque of the engine working in the second direct-drive economic line and the second torque threshold value, controlling the engine to work in the third direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor; the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is basically superposed with the outer characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

In some embodiments of the invention, when the difference between the power-saving target SOC and the SOC of the power battery is greater than a third preset value and less than or equal to a second preset value, the vehicle speed and the wheel end required torque of the hybrid vehicle are also obtained, and when the vehicle speed is greater than or equal to a preset vehicle speed threshold, a first wheel end torque threshold for the hybrid vehicle to enter the parallel mode and a second wheel end torque threshold for the hybrid vehicle to exit the parallel mode are determined according to the SOC of the power battery and the vehicle speed, wherein when the wheel end required torque is greater than or equal to the first wheel end torque threshold and less than or equal to the second wheel end torque threshold, the hybrid vehicle is controlled to enter the second parallel mode; when the wheel end required torque is smaller than a first wheel end torque threshold value, controlling the hybrid vehicle to enter an EV mode; when the wheel end required torque is larger than a second wheel end torque threshold value, controlling the hybrid vehicle to enter a third series mode; and the third preset value is smaller than the second preset value, and the second preset value is smaller than the first preset value.

In some embodiments of the invention, when the vehicle speed is less than the preset vehicle speed threshold, a third wheel end torque threshold value of the hybrid vehicle entering the series mode is further determined according to the SOC of the power battery and the vehicle speed, wherein when the wheel end required torque is greater than or equal to the third wheel end torque threshold value, the hybrid vehicle is controlled to enter the third series mode; and controlling the hybrid vehicle to enter the EV mode when the wheel end required torque is smaller than the third wheel end torque threshold value.

In some embodiments of the present invention, when the hybrid vehicle is operated in the third series mode, the engine is controlled to operate at the first economy line, and the first series generated limiting power is determined from the first economy line and the first rotation speed limiting curve of the engine, and the first constant power generated power is determined from the first constant power generated curve of the engine, and the driving demand power of the hybrid vehicle is obtained, wherein a third larger value between the driving demand power of the hybrid vehicle and the first constant power generated power is determined, and a smaller value between the third larger value and the first series generated limiting power is taken as the series generated power of the engine; and the first economy line and the second economy line are working curves with best efficiency and second best efficiency in the full rotating speed range of the engine, and the output torque of the engine working in the second economy line under the same rotating speed is more than or equal to the output torque of the engine working in the first economy line.

In some embodiments of the present invention, when the hybrid vehicle operates in the second parallel mode, if the wheel-end required torque is less than or equal to a difference between an output torque when the engine operates in the first direct-drive economy line and a third torque threshold value, the engine is controlled to operate in the second direct-drive economy line so that the engine charges the power battery with an output surplus torque through the driving motor or the generator; if the wheel end required torque is larger than the difference between the output torque of the engine working in the first direct-drive economic line and the third torque threshold value and smaller than the difference between the output torque of the engine working in the second direct-drive economic line and the fourth torque threshold value, controlling the engine to work in the corresponding direct-drive economic line according to the requirement of the engine; if the wheel end required torque is larger than or equal to the difference between the output torque of the engine working in the second direct-drive economic line and the fourth torque threshold value, controlling the engine to work in the third direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor; the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is basically superposed with the outer characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

In some embodiments of the invention, when the power conservation function of the hybrid vehicle is not started, driving parameters of the hybrid vehicle are further obtained, the engine, the driving motor and the generator are controlled according to the driving parameters, so that the engine works in an economic area by performing charge and discharge control on the power battery, and an operating mode with the lowest equivalent oil consumption is selected as a current operating mode of the hybrid vehicle by comparing the equivalent oil consumption of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel end demand torque, an SOC of the power battery and a vehicle speed of the hybrid vehicle.

In some embodiments of the invention, when the difference between the power conservation target SOC and the SOC of the power battery is less than or equal to a third preset value, driving parameters of the hybrid vehicle are further obtained, the engine, the driving motor and the generator are controlled according to the driving parameters, so that the engine operates in an economic area by performing charge-discharge control on the power battery, and an operating mode with the lowest equivalent oil consumption is selected as the current operating mode of the hybrid vehicle by comparing the equivalent oil consumption of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel end required torque, the SOC of the power battery and a vehicle speed of the hybrid vehicle.

It should be noted that, for the description of the control method of the hybrid vehicle in the present application, please refer to the description of the hybrid system in the present application, and detailed description thereof is omitted here.

According to the control method of the hybrid vehicle, when the power protection function of the hybrid vehicle is started, the power protection target SOC of the hybrid vehicle is determined, the SOC of the power battery is obtained, when the difference value between the power protection target SOC and the SOC of the power battery is larger than the first preset value, the hybrid vehicle is controlled to enter the first series mode, the engine drives the generator to generate power, and the power battery is continuously charged while the driving motor is powered. Therefore, the requirements of the user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of managing the whole vehicle energy by the user is improved.

In some embodiments, there is also provided a computer-readable storage medium having stored thereon a control program of a hybrid vehicle, which when executed by a processor, implements the foregoing control method of the hybrid vehicle.

According to the computer-readable storage medium of the embodiment of the invention, through the control method of the hybrid vehicle, the requirements of a user on energy management can be met from two dimensions, the target power-saving electric quantity can be interacted, the speed of reaching the target electric quantity can be interacted, and the control experience of the user on managing the energy of the whole vehicle is improved.

Fig. 12 is a schematic structural diagram of a vehicle control unit according to an embodiment of the present invention, and referring to fig. 12, the vehicle control unit 2000 includes a memory 2100, a processor 2200, and a control program of a hybrid vehicle stored in the memory 2100 and operable on the processor, and when the processor 2200 executes the control program of the hybrid vehicle, the control method of the hybrid vehicle is implemented.

It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as 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 more 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). Further, 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 invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following technologies, which are well 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.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like 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 invention. In this specification, the schematic representations of the terms used above do not necessarily 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 more embodiments or examples.

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 to implicitly indicate 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 invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being permanently connected, detachably connected, or integral; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A hybrid powertrain system, comprising:

an engine to selectively output power to a wheel end;

a drive motor to output power to the wheel end;

the generator is connected with the engine to generate electricity under the driving of the engine;

the power battery is used for supplying power to the driving motor and charging according to the alternating current output by the generator or the driving motor;

the controller is configured to determine a power protection target SOC of the hybrid vehicle when a power protection function of the hybrid vehicle is started, acquire the SOC of the power battery, control the hybrid vehicle to enter a first series mode when a difference value between the power protection target SOC and the SOC of the power battery is larger than a first preset value, drive the generator to generate power through the engine, and continuously charge the power battery while supplying power to the driving motor.

2. The hybrid system according to claim 1, wherein when the hybrid vehicle operates in the first series mode, the controller is further configured to control the engine to operate at a second economy line, and determine a second series generated limiting power based on the second economy line and a second rotational speed limiting curve of the engine, and determine a second constant power generated power based on a second constant power generated curve of the engine, and obtain the charging power of the power battery and the drive required power of the hybrid vehicle, and determine the series generated power of the engine based on the second series generated limiting power, the second constant power generated power, the charging power of the power battery, and the drive required power of the hybrid vehicle.

3. The hybrid system of claim 2, wherein the controller is further configured to,

determining a first larger value between the sum of the charging power of the power battery and the driving demand power of the hybrid vehicle and the second constant-power generated power;

and taking the smaller value between the first larger value and the second series power generation limiting power as the series power generation power of the engine.

4. The hybrid system according to any one of claims 1 to 3, wherein when the difference between the power conservation target SOC and the SOC of the power battery is greater than a second preset value and less than or equal to a first preset value, the controller is further configured to acquire a vehicle speed and a wheel end demand torque of the hybrid vehicle, and determine a first wheel end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode, based on the SOC of the power battery and the vehicle speed,

when the vehicle speed is greater than or equal to a preset vehicle speed threshold value, and the wheel end required torque is greater than or equal to a first wheel end torque threshold value and less than or equal to a second wheel end torque threshold value, controlling the hybrid vehicle to enter a first parallel mode;

and when the vehicle speed is less than a preset vehicle speed threshold value, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is less than a first wheel end torque threshold value, or the vehicle speed is greater than or equal to the preset vehicle speed threshold value and the wheel end required torque is greater than a second wheel end torque threshold value, controlling the hybrid vehicle to enter a second series mode.

5. The hybrid system according to claim 4, wherein when the hybrid vehicle operates in the second series mode, the controller is further configured to control the engine to operate at a second economy line, and determine a second series generated limiting power based on the second economy line and a second rotational speed limiting curve of the engine, and determine a second constant power generated power based on a second constant power generated curve of the engine, and obtain the drive demand power of the hybrid vehicle, wherein,

determining a second larger value between the drive required power of the hybrid vehicle and the second constant-power generated power, and regarding a smaller value between the second larger value and the second series generated limiting power as the series generated power of the engine.

6. The hybrid system of claim 4, wherein when the hybrid vehicle is operating in a first parallel mode, the controller is further configured to,

if the wheel end required torque is smaller than or equal to the difference between the output torque of the engine working in the first direct-drive economic line and the first torque threshold value, controlling the engine to work in the second direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor;

if the wheel end required torque is larger than the difference between the output torque of the engine when the engine works in the first direct-drive economic line and the first torque threshold value and is smaller than the difference between the output torque of the engine when the engine works in the second direct-drive economic line and the second torque threshold value, controlling the engine to work in the economic line in the last state;

if the wheel end required torque is larger than or equal to the difference between the output torque of the engine working in a second direct-drive economic line and a second torque threshold value, controlling the engine to work in a third direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor;

the first direct-drive economic line is an optimal economic line in a parallel mode, the third direct-drive economic line is basically superposed with the external characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

7. The hybrid system according to any one of claims 1 to 3, wherein when the difference between the power conservation target SOC and the SOC of the power battery is greater than a third preset value and less than or equal to a second preset value, the controller is further configured to acquire a vehicle speed and a wheel end demand torque of the hybrid vehicle, and determine a first wheel end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode, based on the SOC of the power battery and the vehicle speed when the vehicle speed is greater than or equal to a preset vehicle speed threshold value, wherein,

when the wheel end required torque is larger than or equal to a first wheel end torque threshold value and smaller than or equal to a second wheel end torque threshold value, controlling the hybrid vehicle to enter a second parallel mode;

controlling the hybrid vehicle to enter an EV mode when the wheel end required torque is less than a first wheel end torque threshold;

controlling the hybrid vehicle to enter a third series mode when the wheel end torque demand is greater than a second wheel end torque threshold;

and the third preset value is smaller than the second preset value, and the second preset value is smaller than the first preset value.

8. The hybrid system of claim 7, wherein, when the vehicle speed is less than a preset vehicle speed threshold, the controller is further configured to determine a third wheel end torque threshold at which the hybrid vehicle enters series mode based on the SOC of the power battery and the vehicle speed, wherein,

controlling the hybrid vehicle to enter a third series mode when the wheel end required torque is greater than or equal to a third wheel end torque threshold;

and controlling the hybrid vehicle to enter the EV mode when the wheel end required torque is smaller than a third wheel end torque threshold value.

9. The hybrid system according to claim 7, wherein when the hybrid vehicle operates in a third series mode, the controller is further configured to control the engine to operate at a first economy line, and determine a first series power generation limiting power from the first economy line and a first rotation speed limiting curve of the engine, and determine a first constant power generation power from a first constant power generation curve of the engine, and obtain a drive demand power of the hybrid vehicle, wherein,

determining a third larger value between the drive required power of the hybrid vehicle and the first constant-power generated power, and regarding a smaller value between the third larger value and the first series generated limiting power as the series generated power of the engine;

and the first economy line and the second economy line are working curves with best efficiency and second best efficiency in the full rotating speed range of the engine, and the output torque of the engine working in the second economy line is larger than or equal to the output torque of the engine working in the first economy line under the same rotating speed.

10. The hybrid system of claim 7, wherein when the hybrid vehicle is operating in a second parallel mode, the controller is further configured to,

if the wheel end required torque is smaller than or equal to the difference between the output torque when the engine works on the first direct-drive economic line and a third torque threshold value, controlling the engine to work on a second direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor or the generator;

if the wheel end required torque is larger than the difference between the output torque of the engine when the engine works on a first direct-drive economic line and a third torque threshold value and is smaller than the difference between the output torque of the engine when the engine works on a second direct-drive economic line and a fourth torque threshold value, controlling the engine to work on the corresponding direct-drive economic line according to the requirement of the engine;

if the wheel end required torque is larger than or equal to the difference between the output torque of the engine working in the second direct-drive economic line and the fourth torque threshold value, controlling the engine to work in the third direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor;

the first direct-drive economic line is an optimal economic line of a parallel mode, the third direct-drive economic line is basically overlapped with an external characteristic line of the engine, and the second direct-drive economic line is located between the first direct-drive economic line and the third direct-drive economic line.

11. The hybrid system of claim 7, wherein the controller is further configured to, acquiring driving parameters of the hybrid vehicle when the difference value between the power conservation target SOC and the SOC of the power battery is less than or equal to a third preset value, and controls the engine, the driving motor and the generator according to the driving parameters, so that the engine works in an economic area by carrying out charge and discharge control on the power battery, and by comparing the equivalent oil consumption of the hybrid vehicle in the series mode, the parallel mode and the EV mode, selecting the working mode with the lowest equivalent fuel consumption as the current working mode of the hybrid vehicle, wherein the running parameter includes at least one of a wheel end demand torque, an SOC of the power battery, and a vehicle speed of the hybrid vehicle.

12. The hybrid system according to claim 1, wherein the controller is further configured to obtain driving parameters of the hybrid vehicle when a power conservation function of the hybrid vehicle is not turned on, control the engine, the driving motor and the generator according to the driving parameters, so as to enable the engine to operate in an economic zone by performing charge-discharge control on the power battery, and select an operating mode with the lowest equivalent fuel consumption as the current operating mode of the hybrid vehicle by comparing equivalent fuel consumption of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel-end required torque, an SOC of the power battery and a vehicle speed of the hybrid vehicle.

13. The hybrid power system of claim 1, further comprising a dual electronic control module, wherein the dual electronic control module is respectively connected to the driving motor and the generator, and the dual electronic control module supplies power to the driving motor according to the alternating current output by the generator;

the power battery is connected with the double electric control module, the power battery supplies power to the driving motor through the double electric control module, or the double electric control module charges according to alternating current output by the generator or the driving motor, the double electric control module comprises a first inverter, a second inverter and a DC/DC, an alternating current end of the first inverter is connected to the driving motor, a direct current end of the first inverter is respectively connected with a direct current end of the second inverter and a first direct current end of the DC/DC, an alternating current end of the second inverter is connected to the generator, and a second direct current end of the DC/DC is connected to the power battery.

14. A hybrid vehicle characterized by comprising the hybrid system according to any one of claims 1 to 13.

15. A control method of a hybrid vehicle, the hybrid vehicle including an engine for selectively outputting power to a wheel end, a driving motor for outputting power to the wheel end, a generator connected to the engine for generating electricity under the drive of the engine, and a power battery for supplying power to the driving motor and charging according to an alternating current output from the generator or the driving motor, the control method comprising:

determining a power protection target SOC of a hybrid vehicle when a power protection function of the hybrid vehicle is started, and acquiring the SOC of a power battery;

and when the difference value between the power-maintaining target SOC and the SOC of the power battery is larger than a first preset value, controlling the hybrid vehicle to enter a first series mode, driving the generator to generate power through the engine, and continuously charging the power battery while supplying power to the driving motor.

16. The control method of a hybrid vehicle according to claim 15, characterized in that when the hybrid vehicle is operating in the first series mode, the engine is controlled to operate at a second economy line, and a second series power generation limiting power is determined from the second economy line and a second rotational speed limiting curve of the engine, and a second constant power generation power is determined from a second constant power generation curve of the engine, and the charging power of the power battery and the drive demand power of the hybrid vehicle are acquired, and the series power generation power of the engine is determined from the second series power generation limiting power, the second constant power generation power, the charging power of the power battery, and the drive demand power of the hybrid vehicle.

17. The control method of the hybrid vehicle according to claim 16, wherein determining the series generated power of the engine based on the second series generated limiting power, the second constant-power generated power, the charging power of the power battery, and the drive required power of the hybrid vehicle includes:

18. The control method of a hybrid vehicle according to any one of claims 15-17, characterized in that when the difference between the power conservation target SOC and the SOC of the power battery is greater than a second preset value and equal to or less than a first preset value, a vehicle speed and a wheel end demand torque of the hybrid vehicle are also acquired, and a first wheel end torque threshold value at which the hybrid vehicle enters a parallel mode and a second wheel end torque threshold value at which the hybrid vehicle exits the parallel mode are determined based on the SOC of the power battery and the vehicle speed, wherein,

19. The control method of a hybrid vehicle according to claim 18, characterized in that when the hybrid vehicle is operated in a second series mode, the engine is controlled to operate at a second economy line, and a second series power generation limiting power is determined based on the second economy line and a second rotation speed limiting curve of the engine, and a second constant power generation power is determined based on a second constant power generation curve of the engine, and a drive request power for the hybrid vehicle is obtained, wherein,

a second larger value between the drive required power of the hybrid vehicle and the second constant-power generated power is determined, and a smaller value between the second larger value and the second series generated limiting power is taken as the series generated power of the engine.

20. The control method of a hybrid vehicle according to claim 18, characterized in that, when the hybrid vehicle is operating in a first parallel mode,

if the wheel end required torque is smaller than or equal to the difference between the output torque when the engine works in the first direct-drive economic line and the first torque threshold value, controlling the engine to work in the second direct-drive economic line so that the engine can charge the power battery with the output redundant torque through the driving motor;

21. The control method of a hybrid vehicle according to any one of claims 15 to 17, characterized in that when a difference between the power conservation target SOC and the SOC of the power battery is greater than a third preset value and equal to or less than a second preset value, a vehicle speed and a wheel-end required torque of the hybrid vehicle are also acquired, and when the vehicle speed is equal to or greater than a preset vehicle speed threshold value, a first wheel-end torque threshold value at which the hybrid vehicle enters the parallel mode and a second wheel-end torque threshold value at which the hybrid vehicle exits the parallel mode are determined based on the SOC of the power battery and the vehicle speed, wherein,

controlling the hybrid vehicle to enter an EV mode when the wheel-end torque demand is less than a first wheel-end torque threshold;

22. The control method of a hybrid vehicle according to claim 21, characterized in that a third wheel end torque threshold value at which the hybrid vehicle enters a series mode is determined also in accordance with the SOC of the power battery and the vehicle speed when the vehicle speed is less than a preset vehicle speed threshold value, wherein,

when the wheel end required torque is larger than or equal to a third wheel end torque threshold value, controlling the hybrid vehicle to enter a third series mode;

controlling the hybrid vehicle to enter an EV mode when the wheel end required torque is less than a third wheel end torque threshold.

23. The control method of a hybrid vehicle according to claim 21, characterized in that when the hybrid vehicle is operated in a third series mode, the engine is controlled to operate at a first economy line, and a first series electric power generation limiting power is determined based on the first economy line and a first rotation speed limiting curve of the engine, and a first constant power electric power generation power is determined based on a first constant power electric power generation curve of the engine, and a drive demand power of the hybrid vehicle is obtained, wherein,

24. The control method of a hybrid vehicle according to claim 21, characterized in that when the hybrid vehicle is operated in a second parallel mode,

if the wheel end required torque is larger than the difference between the output torque of the engine when the engine works in a first direct-drive economic line and a third torque threshold value and is smaller than the difference between the output torque of the engine when the engine works in a second direct-drive economic line and a fourth torque threshold value, controlling the engine to work in the corresponding direct-drive economic line according to the requirement of the engine;

25. The control method of the hybrid vehicle according to claim 15, wherein when the power conservation function of the hybrid vehicle is not started, driving parameters of the hybrid vehicle are further acquired, the engine, the driving motor and the generator are controlled according to the driving parameters, so that the engine operates in an economic zone by performing charge and discharge control on the power battery, and an operating mode with the lowest equivalent fuel consumption is selected as a current operating mode of the hybrid vehicle by comparing equivalent fuel consumption of the hybrid vehicle in a series mode, a parallel mode and an EV mode, wherein the driving parameters include at least one of a wheel end required torque, an SOC of the power battery and a vehicle speed of the hybrid vehicle.

26. The control method of a hybrid vehicle according to claim 21, when the difference value between the power-maintaining target SOC and the SOC of the power battery is smaller than or equal to a third preset value, driving parameters of the hybrid vehicle are also acquired, and controls the engine, the driving motor and the generator according to the driving parameters, so that the engine works in an economic area by controlling the charging and discharging of the power battery, and by comparing the equivalent oil consumption of the hybrid vehicle in the series mode, the parallel mode and the EV mode, selecting the working mode with the lowest equivalent fuel consumption as the current working mode of the hybrid vehicle, wherein the running parameter includes at least one of a wheel end demand torque, an SOC of the power battery, and a vehicle speed of the hybrid vehicle.

27. A computer-readable storage medium, characterized in that a control program of a hybrid vehicle is stored thereon, which when executed by a processor implements the control method of the hybrid vehicle according to any one of claims 15 to 26.

28. A vehicle control unit comprising a memory, a processor and a control program for a hybrid vehicle stored on the memory and executable on the processor, the processor implementing the control method for a hybrid vehicle as claimed in any one of claims 15 to 26 when executing the control program for a hybrid vehicle.