CN110962616B - Vehicle composite energy system integrating hydraulic power and battery and control method thereof - Google Patents

Vehicle composite energy system integrating hydraulic power and battery and control method thereof Download PDF

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CN110962616B
CN110962616B CN201911323295.5A CN201911323295A CN110962616B CN 110962616 B CN110962616 B CN 110962616B CN 201911323295 A CN201911323295 A CN 201911323295A CN 110962616 B CN110962616 B CN 110962616B
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motor
hydraulic
braking
vehicle
energy
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CN110962616A (en
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傅兵
朱泰平
孟步敏
刘金刚
王伟达
胡余良
刘杰
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Xiangtan University
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Xiangtan University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L7/00—Electrodynamic brake systems for vehicles in general
    • B60L7/10—Dynamic electric regenerative braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B60L15/2009—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed for braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B60L15/2054—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed by controlling transmissions or clutches
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention provides a vehicle composite energy system integrating hydraulic power and a battery and a control method thereofThe system comprises an electro-hydraulic control module, a bidirectional hydraulic motor, a speed reducing mechanism, a clutch, a driving motor, a speed reducer, a battery, a motor controller, a battery management system, a brake power-assisted control unit and a CAN bus; an output shaft of the bidirectional hydraulic motor is connected with one end of a rotor of the driving motor through a speed reducing mechanism and a clutch, and the other end of the rotor of the driving motor is connected with a wheel through a speed reducer; the bidirectional hydraulic motor control port is electrically connected with the electro-hydraulic control module, and the bidirectional hydraulic motor, the electro-hydraulic control module, the clutch, the battery management system and the brake power-assisting control unit are connected in parallel on the CAN bus. The invention can be used in the batterySOCAnd the braking energy recovery is implemented under the working conditions that the value is higher than the highest charging threshold and the rotating speed of the driving system is lower than the lowest power generation threshold rotating speed of the motor, the working condition range of the braking energy recovery is expanded, and the braking energy recovery proportion is improved.

Description

Vehicle composite energy system integrating hydraulic power and battery and control method thereof
Technical Field
The invention belongs to the technical field of new energy automobiles, and particularly relates to a vehicle composite energy system integrating hydraulic power and a battery and a control method thereof.
Background
The pure electric automobile technology is developed rapidly and becomes the development direction of the traditional automobile. The energy-saving main contribution point of the pure electric vehicle compared with the traditional fuel vehicle is that the braking energy recovery can be realized through the motor, and the energy-saving effect of the electric vehicle depends on the braking energy recovery efficiency of the vehicle under the circulating working condition to a great extent. The existing pure electric vehicle takes a battery as an energy storage device, and when a driver brakes, a whole vehicle control system controls a driving motor to be switched into a power generation mode to provide braking torque so as to realize braking energy recovery.
However, in the existing energy storage system of the electric vehicle, the recovery efficiency of the braking energy is limited by the rotation speed of the motor and the SOC state of the battery, so that the recovery efficiency of the energy is not high. On one hand, the driving motor has a power generation rotating speed threshold value, when the rotating speed of the motor is lower than a certain threshold value during braking, the counter electromotive force (induced electromotive force) of the motor is too low, the self energy consumption is larger than the recovered energy, the power generation mode needs to be exited, and at the moment, the kinetic energy of the vehicle can be consumed only through mechanical friction braking. On the other hand, when the SOC of the battery is in the high value range, the battery is overcharged due to further charging, which may reduce the life of the battery pack or damage the battery pack, so that the new energy vehicle energy management system is provided with a chargeable SOC limit value, and when the SOC is higher than the limit value, the implementation of the braking energy recovery is prohibited. The above limitation results in low braking energy recovery ratio of the electric vehicle under the circulation working condition, and the improvement of the energy-saving effect of the whole vehicle is limited. Therefore, how to increase the braking energy recovery ratio becomes one of the urgent technical bottlenecks to be solved in the process of improving the economy of the electric vehicle.
Disclosure of Invention
In order to solve the technical problems, the invention provides a hydraulic and battery integrated vehicle composite energy system and a control method thereof, which can effectively improve the braking energy recovery efficiency of an electric vehicle, enlarge the working condition range of the electric vehicle for implementing the braking energy recovery, improve the braking energy recovery ratio and improve the energy-saving effect of the electric vehicle.
The technical scheme adopted by the invention is as follows: a vehicle composite energy system integrating hydraulic power and a battery comprises a vehicle control unit, a hydraulic energy accumulator, an electro-hydraulic control module, a bidirectional hydraulic motor, a speed reducing mechanism, a clutch, a driving motor, a battery, a motor controller, a battery management system, a braking power-assisted control unit and a CAN bus;
an output shaft of the bidirectional hydraulic motor is connected with one end of a rotor of the driving motor through a speed reducing mechanism and a clutch, and the other end of the rotor of the driving motor is connected with a wheel through a speed reducer; two oil inlets of the bidirectional hydraulic motor are respectively connected with the oil tank and the hydraulic energy accumulator, an oil inlet of the hydraulic energy accumulator is connected with an oil outlet of the electro-hydraulic control module, and an oil inlet of the electro-hydraulic control module is connected with an oil outlet of the bidirectional hydraulic motor; the control port of the bidirectional hydraulic motor is electrically connected with the electro-hydraulic control module;
the driving motor is electrically connected with the motor controller, the wheel is provided with a mechanical braking mechanism, and the mechanical braking mechanism is electrically connected with the brake power-assisted control unit; the battery is electrically connected with the battery management system; the electro-hydraulic control module, the clutch, the motor controller, the battery management system and the braking power-assisted control unit are connected in parallel on a CAN bus, and the CAN bus is electrically connected with the whole vehicle controller.
The control method of the vehicle composite energy system integrating the hydraulic power and the battery is characterized in that: when a driver steps on an accelerator pedal, the vehicle enters a driving mode; calculating the required power P of a driver by the mass of the whole automobile, the speed, the windward area of the automobile, the rotational inertia of a flywheel, the rotational inertia of wheels, the opening degree of an accelerator pedal and the opening degree change rate of the accelerator pedal; the vehicle control unit calculates the energy storage state E of the hydraulic energy storage according to the real-time pressure of the hydraulic energy storage, the gas volume corresponding to the lowest pressure and the gas polytropic exponentc(ii) a The vehicle control unit passes through the energy storage state E of the hydraulic energy storage devicecCalculating the output driving power P of the bidirectional hydraulic motor according to the energy supply cycle time of the bidirectional hydraulic motor, the efficiency of the speed reducing mechanism and the efficiency of the speed reducerhyd(ii) a According to the current motor rotating speed on the CAN bus, the output driving power P of the driving motor is obtained by combining the transmission ratio and the transmission efficiency through the motor rotating speed-torque MAP stored in the vehicle control unitmo(ii) a The vehicle control unit is according to hydraulic pressure accumulator energy storage state EcPower required by driver P, output driving power P of bidirectional hydraulic motorhydOutput drive power P of drive motormoSelecting and controlling a driving mode;
when a driver steps on a brake pedal, the vehicle enters a brake energy recovery mode; the vehicle brake power-assisted control unit calculates the target brake force F of the driver on the axle where the driving motor and the bidirectional hydraulic motor are positioned through the opening of a brake pedal, the distance from a front axle to the mass center, the axle distance of the automobile and the mass of the whole automobile on a CAN bust(ii) a The vehicle control unit controls the gas volume and the gas polytropic exponent corresponding to the real-time pressure and the lowest pressure of the hydraulic energy storage deviceCalculating the energy storage state E of the hydraulic energy accumulatorc(ii) a The vehicle control unit passes through the energy storage state E of the hydraulic energy storage devicecCalculating the braking force F provided by the bidirectional hydraulic motor according to the energy supply cycle time of the bidirectional hydraulic motor, the center speed of the tire, the efficiency of the speed reducing mechanism and the efficiency of the speed reducerbf(ii) a According to the current motor rotating speed data on the CAN bus, the motor rotating speed-torque MAP stored in the vehicle control unit is combined with the transmission ratio, the reducer efficiency and the tire radius to obtain the braking force F provided by the driving motormf(ii) a The vehicle control unit brakes F according to the target brake force of the drivertBraking force F provided by bidirectional hydraulic motorbfThe driving motor can provide braking force FmfAnd the energy storage state E of the hydraulic energy storage devicecThe braking energy recovery mode is selected and controlled.
In the control method of the hybrid energy system of the vehicle integrating hydraulic power and the battery, the specific method for selecting and controlling the driving mode is as follows:
if the energy E of the hydraulic accumulatorcLess than the minimum energy EminNamely the hydraulic energy accumulator does not store energy; at the moment, the vehicle control unit controls the clutch to be disconnected and starts the driving motor, and the vehicle control unit controls the vehicle composite energy system integrating hydraulic power and the battery to be driven in an electric driving mode;
if the energy E of the hydraulic accumulatorcNot less than the minimum energy EminWhen the hydraulic energy accumulator stores energy, the hydraulic energy accumulator stores energy; if the power P required by the driver is not more than the output driving power P of the bidirectional hydraulic motorhydThe vehicle controller controls the clutch to be combined, controls the bidirectional hydraulic motor to be switched into a motor mode, and controls the vehicle composite energy system integrating hydraulic power and the battery to be driven in a hydraulic driving mode;
if the energy E of the hydraulic accumulator 2cNot less than the minimum energy EminWhen the hydraulic energy accumulator 2 stores energy; further, if the driver demand power P is larger than the output driving power P of the bidirectional hydraulic motor 3hydThe vehicle control unit controls the clutch 6 to be combined and controls the bidirectional hydraulic motor 3 to be switched into the motor mode, and meanwhile, the vehicle control unit controls the bidirectional hydraulic motor 3 to be switched into the motor modeControlling the driving motor 7 to start, and enabling the sum of the power of the driving motor 7 and the output driving power of the bidirectional hydraulic motor 3 to be equal to the power required by the driver, namely P is equal to Phyd+PmoAnd the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to perform hybrid driving by adopting hydraulic power and electric power.
In the control method of the vehicle composite energy system integrating hydraulic power and the battery, the specific method for selecting and controlling the braking energy recovery mode is as follows:
after the vehicle enters a braking energy recovery mode, if the rotating speed n of the driving motor is less than the lowest power generation threshold rotating speed n of the motor in an axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the braking force F provided by the bidirectional hydraulic motorbfNot less than target braking force F required for the axletWhen the vehicle is in a braking mode, the vehicle controller controls the clutch to be combined and controls the bidirectional hydraulic motor to be switched into an oil pump mode, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and a battery to enter the bidirectional hydraulic motor braking mode;
in the axle connected with the driving motor and the bidirectional hydraulic motor together, if the rotating speed n of the driving motor is less than the minimum power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the braking force F provided by the bidirectional hydraulic motorbfLess than the target braking force F required for the axletWhen the vehicle is in a hydraulic braking mode, the vehicle controller controls the clutch to be combined and controls the bidirectional hydraulic motor to be switched to an oil pump mode, the bidirectional hydraulic motor provides a part of braking force, and the rest required braking force is provided by a vehicle mechanical braking system;
if the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd drives the motor stationCapable of providing braking force FmfWhen the braking force is not less than the target braking force required by the axle, the bidirectional hydraulic motor cannot provide the braking force, and the vehicle control unit controls the clutch to be separated; at the moment, the braking force is provided by the driving motor independently, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a motor independent braking mode;
if the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd the braking force F provided by the driving motormfLess than the target braking force F required for the axletWhen the vehicle is in a driving state, the vehicle controller controls the clutch to be disengaged; the driving motor works in a braking mode to provide a part of braking force and the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+FmmAnd the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a braking mode combining motor braking and mechanical braking.
If the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the sum F of the braking forces provided by the driving motor and the bidirectional hydraulic motormf+FbfNot less than target braking force F required for the axletAnd the vehicle controller controls the vehicle composite energy system integrating hydraulic power and a battery to enter a braking mode combining bidirectional hydraulic motor braking and motor braking.
In the axle connected with the electric motor and the bidirectional hydraulic motor in a driving way, if the rotating speed n of the driving electric motor is not less than the minimum power generation threshold rotating speed n of the electric motorminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the sum F of the braking forces provided by the driving motor and the bidirectional hydraulic motormf+FbfLess than the target braking force F required for the axletWhen the vehicle controller controls the clutch to be combined, the bidirectional hydraulic motor is controlled to be switched into the oil pump mode, the driving motor works in the braking mode, the two motors provide part of braking force, and the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+Fbf+FmmAnd the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a braking mode combining motor braking, bidirectional hydraulic motor braking and mechanical braking.
In the axle connected with the driving motor and the bidirectional hydraulic motor together, if the rotating speed n of the driving motor is less than the lowest generating threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd at the moment, the driving motor and the hydraulic energy accumulator can not recover energy, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a pure mechanical braking mode.
In the control method of the vehicle composite energy system integrating the hydraulic power and the battery, a relation curve between target braking force and braking pedal feedback force is obtained in advance through tests and stored in a vehicle controller, a vehicle enters a braking energy recovery mode, when a bidirectional hydraulic motor or a driving motor brakes alone, the relation curve between the target braking force and the braking pedal feedback force is inquired to obtain the target pedal feedback force required by the braking system, a braking assistance ratio is adjusted in real time through a braking assistance control unit, an actual pedal feedback force is measured in real time through a force sensor arranged at a braking pedal, and the braking assistance ratio is adjusted through closed-loop feedback of the braking assistance control unit, so that the feedback force obtained at the pedal position of a driver is consistent with the target feedback force during mechanical braking, and a stable braking process is obtained.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the invention, the braking energy recovery can be implemented under the working conditions that the SOC of the battery is higher than the chargeable threshold and the rotating speed of the driving system is lower than the rotating speed of the motor capable of generating power threshold, the working condition range of the braking energy recovery is enlarged, the braking energy recovery proportion is improved, the unit mileage power consumption of the electric automobile is reduced, and the whole automobile economy is improved;
(2) the invention improves the total driving power of the automobile, and particularly, compared with the electric automobile using a single driving source, the electric automobile matched with the system has better dynamic property when the automobile is started under heavy load.
(3) The invention can generate the pedal feedback force consistent with the traditional fuel vehicle and improve the driveability of the electric vehicle.
Drawings
Fig. 1 is a schematic diagram of the hybrid vehicle propulsion and energy recovery system of the present invention incorporating both hydraulic and electric power.
Fig. 2 is a block diagram illustrating the selection and control of the driving mode in the hybrid driving and energy recovery system for a vehicle integrating hydraulic power and electric power according to the present invention.
FIG. 3 is a block diagram illustrating the selection and control of the braking energy recovery mode in the hybrid propulsion and energy recovery system of the integrated hydraulic and electric vehicle of the present invention.
FIG. 4 is a block diagram of a brake pedal force simulation method in the hybrid propulsion and energy recovery system of the integrated hydraulic and electric vehicle of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
The invention discloses a hydraulic and battery integrated vehicle composite energy system, which comprises a hydraulic energy accumulator 2, an electro-hydraulic control module 1, a bidirectional hydraulic motor 3, a speed reducing mechanism 5, a clutch 6, a driving motor 7, a battery 13, a motor controller 14, a battery management system 12, a braking power-assisted control unit 11, a CAN bus 15 and a vehicle control unit 16;
an output shaft of the bidirectional hydraulic motor 3 is connected with one end of a rotor of a driving motor 7 through a speed reducing mechanism 5 and a clutch 6, and the other end of the rotor of the driving motor 7 is connected with a wheel 9 through a speed reducer 8. Two oil inlets of the bidirectional hydraulic motor 3 are respectively connected with the oil tank 4 and the hydraulic energy accumulator 2, an oil inlet of the hydraulic energy accumulator 2 is connected with an oil outlet of the electro-hydraulic control module 1, and an oil inlet of the electro-hydraulic control module 1 is connected with an oil outlet of the bidirectional hydraulic motor 3; and a control port of the bidirectional hydraulic motor 3 is electrically connected with the electro-hydraulic control module 1.
The driving motor 7 is electrically connected with the motor controller 14, the wheel 9 is provided with a mechanical braking mechanism 10, and the mechanical braking mechanism 10 is electrically connected with the brake power-assisted control unit 11; the battery 13 is electrically connected to the battery management system 12. The electro-hydraulic control module 1, the clutch 6, the motor controller 14, the battery management system 12 and the braking assistance control unit 11 are connected in parallel on a CAN bus 15, and the CAN bus 15 is electrically connected with the vehicle control unit 16.
The electro-hydraulic control module 1: the system is used for executing the working mode switching of the bidirectional hydraulic motor 3, the working state detection of the hydraulic energy accumulator 2 and the safety failure protection, sending the working parameters of the hydraulic energy accumulator 2 and the bidirectional hydraulic motor 3 to the vehicle control unit 16, and receiving and executing the command of the vehicle control unit 16.
The hydraulic energy accumulator 2: the space for storing hydraulic oil absorbs hydraulic energy through the built-in elastic element.
Bidirectional hydraulic motor 3: the system is used for driving the whole vehicle to run and recovering energy and is provided with a motor mode and a hydraulic pump mode. When the whole vehicle is driven to run, the vehicle works in a motor working mode, and hydraulic energy in the hydraulic energy accumulator 2 is converted into mechanical energy. When energy is recovered, the two-way hydraulic motor works in a hydraulic pump mode, and when the two-way hydraulic motor 3 is returned to the hydraulic accumulator 2, braking torque is provided.
The speed reduction mechanism 5: when the bidirectional hydraulic motor 3 works in the motor mode, the bidirectional hydraulic motor 3 is decelerated; when the bidirectional hydraulic motor 3 works in the hydraulic pump mode, the speed of the driving motor 7 is increased.
The driving motor 7: the system is used for consuming electric energy to drive the vehicle to run or recovering mechanical energy of the vehicle through power generation.
Brake assist control unit 11: the method is used for adjusting the brake boosting ratio, detecting and sending booster working parameters to the vehicle control unit 16, and receiving and executing commands of the vehicle control unit 16.
The battery management system 12: and the controller is used for detecting and sending the operating parameters of the battery 13 to the vehicle controller 16, and receiving and executing the command of the vehicle controller 16 according to the operating mode and the operating state of the battery 13.
The motor controller 14: the controller is used for controlling the running state of the driving motor 7, detecting and sending motor working parameters to the vehicle control unit 16, and receiving and executing commands of the vehicle control unit 16. A battery 13: for storing or releasing electrical energy.
CAN bus 15: the signal transmission among the control units is realized.
The vehicle control unit 16: the system is used for acquiring state parameters and signals of the electro-hydraulic control module 1, the battery management system 12, the motor controller and the brake power-assisted control unit 11 and outputting control parameters to the electro-hydraulic control module 1, the battery management system 12, the motor controller and the brake power-assisted control unit 11 according to a built-in control strategy.
The invention discloses a control method of a vehicle driving and energy recovery system integrating hydraulic power and electric power, which specifically comprises the following operations:
in the running process of the vehicle, the vehicle control unit 16 calculates the required power P of the vehicle and the target braking force F of the driver in real time according to the signals on the CAN bus 15tEnergy state of the accumulator EcOutput drive power P of the bidirectional hydraulic motor 3hydAnd the driving and braking energy recovery mode control is implemented according to the set decision logic by combining the battery energy state SOC on the CAN bus and the motor rotating speed n. The calculation method of each parameter is as follows:
calculating the required power P of the vehicle: when the vehicle is running straight, the running resistance includes rolling resistance of the ground to the tire, air resistance, road slope resistance, and acceleration resistance. The driving force required by the vehicle needs to be balanced with the running resistance so as to drive the vehicle to run. Vehicle required driving force FtrThe calculation method is as follows: ftr＝Ff+Fw+Fi+Fj(ii) a In the formula: ffTo rolling resistance, FwAs air resistance, FiAs slope resistance, FjFor acceleration resistance. The vehicle required power P calculation method is as follows: p ═ Ftru; in the formula: u is the center velocity of the car tire.
Driver target braking force FtAnd (3) calculating: the vehicle in the embodiment is a front-drive vehicle, the driving motor 7 and the bidirectional hydraulic motor 3 are positioned on a front axle, the front axle recovers braking energy, and the braking force of the front axle and the braking force of the rear axle should be reasonably distributed in the braking process of the vehicle to prevent the front wheel from locking before the rear wheel, so that the slip rates of the front wheel and the rear wheel can be controlled to be close to the optimal slip rate as far as possible. In the embodiment, an ideal braking force distribution strategy is adopted, so that the braking force of the front axle and the rear axle is close to an ideal I curve as far as possible on the premise of ensuring the braking efficiency, and the brake system has good braking comfort. When the braking strength is less than or equal to the ground adhesion coefficient, the target braking strength z of the vehicle can be calculated through the opening degree of a brake pedal to obtain:
z＝Ax2+Bx
in the formula, x is a brake pedal opening degree signal, and A and B are coefficients related to the brake pedal opening degree.
The braking forces of the front and rear wheel axles of the vehicle are calculated by the following formula:
Figure GDA0002362269480000061
Figure GDA0002362269480000062
in the formula, FtFor front wheel braking force, FhIs the rear wheel braking force, m is the total vehicle mass, ltDistance of front axle to center of mass,/tIs the distance from the rear axle to the center of mass, l is the wheelbase, hgIs the vehicle centroid height and z is the target brake intensity.
Energy state E of hydraulic accumulator 2cAnd (3) calculating: the hydraulic accumulator 2 used in the invention is a gasbag type hydraulic accumulator. The energy conversion and transmission of the air bag type hydraulic energy accumulator are completed through a thermodynamic process. Current energy storage state E of hydraulic energy accumulatorcCan be solved through gas volume, gaseous polytropic exponent and the gas constant meter when accumulator minimum pressure, the real-time pressure of accumulator, corresponding pressure, the computational formula is as follows:
Figure GDA0002362269480000063
in the formula, V0For energy storage corresponds to p0Gas pressure of VtEnergy storage device correspondence ptPressure of gas of p0For the lowest working pressure of the accumulator, ptThe real-time working pressure of the energy accumulator is shown, n is a gas polytropic exponent, and 1.1 is taken.
Output drive power P of the bidirectional hydraulic motor 3hydAnd (3) calculating: it is assumed here that the period of the energizing cycle of the bidirectional hydraulic motor 3 is t and the energy per cycle transferred from the accumulator to the bidirectional hydraulic motor 3 is EsThe calculation formula of the output power which can be provided by the energy storage device for the bidirectional hydraulic motor 3 is as follows:
Figure GDA0002362269480000071
in the formula etar1For efficiency of the reduction mechanism, ηr2For retarder efficiency.
Braking force F provided by bidirectional hydraulic motorbfAnd (3) calculating:
Figure GDA0002362269480000072
wherein u is the tire center speed.
As shown in fig. 1 to 4, a control method of a hybrid energy system of a vehicle integrating hydraulic power and a battery is disclosed, in which when a driver depresses an accelerator pedal, the vehicle enters a driving mode. The vehicle controller 16 calculates the driver demand power P according to the vehicle mass, the vehicle speed, the windward area of the vehicle, the flywheel rotational inertia, the wheel rotational inertia, the accelerator pedal opening degree, and the accelerator pedal opening degree change rate. The vehicle control unit 16 calculates the energy storage state E of the hydraulic energy storage device 2 according to the real-time pressure, the lowest pressure, the gas volume corresponding to the real-time pressure, and the gas polytropic exponent of the hydraulic energy storage device 2c(ii) a The vehicle control unit 16 stores energy through hydraulic pressureEnergy storage state E of device 2cCalculating the output driving power P of the bidirectional hydraulic motor 3 according to the energy supply cycle time of the bidirectional hydraulic motor 3, the efficiency of the speed reducing mechanism 5 and the efficiency of the speed reducer 8hyd(ii) a The vehicle control unit 16 calculates the output driving power P of the driving motor 7 according to the motor speed on the CAN bus 15, the motor speed-torque MAP stored in the vehicle control unit 16, and the reducer efficiencymo(ii) a The vehicle control unit 16 stores energy according to the energy storage state E of the hydraulic energy storage 2cDriver demand power P, output drive power P of the bidirectional hydraulic motor 3hydOutput drive power P of drive motor 7moSelection and control of the drive mode are performed. The selection and operation method of each driving mode is as follows:
if the hydraulic accumulator 2 is charged with energy EcLess than the minimum energy EminI.e. the hydraulic accumulator 2 is not charged. At the moment, the vehicle control unit 16 controls the clutch 6 to be disconnected, the driving motor 7 is started, and the vehicle control unit 16 controls the vehicle composite energy system integrating hydraulic power and the battery to be driven in an electric driving mode.
If the hydraulic accumulator 2 is charged with energy EcNot less than the minimum energy EminWhen the hydraulic energy accumulator 2 stores energy; if the driver demand power P is not greater than the output driving power P of the bidirectional hydraulic motor 3hydAnd then the vehicle control unit 16 controls the clutch 6 to be combined, the bidirectional hydraulic motor 3 is switched to a motor mode, and the vehicle control unit 16 controls the vehicle composite energy system integrating hydraulic power and a battery to be driven in a hydraulic driving mode.
If the hydraulic accumulator 2 is charged with energy EcNot less than the minimum energy EminWhen the hydraulic energy accumulator 2 stores energy; if the driver demand power P is larger than the output driving power P of the bidirectional hydraulic motor 3hydThe vehicle control unit 16 controls the clutch 6 to be engaged, controls the bidirectional hydraulic motor 3 to be switched to the motor mode, and controls the driving motor 7 to be started at the same time, so that the sum of the power of the driving motor 7 and the output driving power of the bidirectional hydraulic motor 3 is equal to the power required by the driver, namely P is Phyd+PmoVehicle composite energy system integrating hydraulic power and battery controlled by vehicle controller 16The system adopts hydraulic power and electric power for hybrid driving.
As shown in fig. 1 and 3, when the driver depresses the brake pedal during the running of the vehicle, the vehicle enters a braking energy recovery mode. The vehicle brake power-assisted control unit 11 calculates the target brake force F of the driver on the axle where the driving motor 7 and the bidirectional hydraulic motor 3 are positioned through the brake pedal opening degree signal, the brake cylinder pressure, the vehicle speed, the whole vehicle mass, the vehicle brake disc parameters, the adhesion coefficient, the wheel slip rate, the wheel radius, the center speed of the vehicle tyre and the brake force distribution curves of the front wheel and the rear wheel of the vehicle on the CAN bus 15t(ii) a Calculating the energy storage state E of the hydraulic energy storage device 2 according to the real-time pressure, the lowest pressure, the corresponding gas volume and the gas polytropic exponential parameter of the hydraulic energy storage device 2c(ii) a The vehicle control unit 16 passes through the energy storage state E of the hydraulic energy storage devicecCalculating the braking force F provided by the bidirectional hydraulic motor according to the energy supply cycle time of the bidirectional hydraulic motor, the center speed of the tire, the efficiency of the speed reducing mechanism and the efficiency of the speed reducerbf(ii) a According to the current motor rotating speed data on the CAN bus 15, the motor rotating speed-torque MAP stored in the vehicle control unit 16 is combined with the transmission ratio, the reducer efficiency and the tire radius to obtain the braking force F provided by the driving motor 7mf. The vehicle control unit 16 controls the braking force F according to the target driver braking forcetThe bidirectional hydraulic motor 3 can provide braking force FbfThe driving motor 7 can provide braking force FmfAnd the energy storage state E of the hydraulic energy storage 2cThe braking energy recovery mode is selected and controlled. The selection and operation method of each braking energy recovery mode is as follows:
as shown in fig. 1 and 3, after the vehicle enters the braking energy recovery mode, the vehicle controller 16 collects data through the CAN bus 15 to select the braking energy recovery mode:
if the rotating speed n of the driving motor 7 is less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cLess than maximum energy EmaxAnd the bidirectional hydraulic motor 3 can provide a braking force FbfNot less than target braking force F required for the axletThe vehicle control unit 16 controls the clutch 6 to be combined, andthe bidirectional hydraulic motor 3 is controlled to be switched to an oil pump mode, the braking force of the vehicle is independently provided by the bidirectional hydraulic motor 3, and the vehicle control unit 16 controls the vehicle composite energy system integrating hydraulic power and a battery to enter the bidirectional hydraulic motor braking mode.
If the rotating speed n of the driving motor 7 is less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cLess than maximum energy EmaxAnd the bidirectional hydraulic motor 3 can provide a braking force FbfLess than the target braking force F required for the axletWhen the vehicle controller 16 controls the clutch 6 to be combined, the bidirectional hydraulic motor 3 is controlled to be switched to an oil pump mode, the bidirectional hydraulic motor 3 provides a part of braking force, the rest required braking force is provided by a vehicle mechanical braking system, and the vehicle controller 16 controls the vehicle composite energy system integrating hydraulic power and a battery to enter a braking mode combining bidirectional hydraulic motor braking and mechanical braking.
If the rotating speed n of the driving motor 7 is not less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cEqual to the highest energy EmaxAnd the driving motor 7 can provide a braking force FmfNot less than target braking force F required for the axletIn time, the bidirectional hydraulic motor 3 cannot provide braking force, and the vehicle control unit 16 controls the clutch 6 to be disengaged. At the moment, the axle braking force is provided by the driving motor 7 alone, and the vehicle control unit 16 controls the vehicle composite energy system integrating hydraulic power and the battery to enter a motor alone braking mode.
If the rotating speed n of the driving motor 7 is not less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cEqual to the highest energy EmaxAnd the braking force F provided by the driving motor 7mfLess than the target braking force F required for the axletIn time, the bidirectional hydraulic motor 3 cannot provide braking force, and the vehicle control unit 16 controls the clutch 6 to be disengaged. The driving motor 7 works in a braking mode at the moment, a part of braking force is provided, and the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+FmmVehicle controller 16 controls vehicle integrating hydraulic power and batteryThe hybrid energy system enters a braking mode combining motor braking and mechanical braking.
If the rotating speed n of the driving motor 7 is not less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cLess than maximum energy EmaxAnd the sum F of the braking forces which can be provided by the drive motor 7 and the bidirectional hydraulic motor 3mf+FbfNot less than target braking force F required for the axletDuring the process, the vehicle control unit 16 controls the clutch 6 to be combined, controls the bidirectional hydraulic motor 3 to be switched to an oil pump mode, provides the braking force of the axle by the driving motor 7 and the bidirectional hydraulic motor 3 together, and controls the vehicle composite energy system integrating hydraulic power and the battery to enter a braking mode combining bidirectional hydraulic motor braking and motor braking by the vehicle control unit 16.
If the rotating speed n of the driving motor 7 is not less than the lowest power generation threshold rotating speed n of the driving motorminEnergy storage state E of the hydraulic energy store 2cLess than maximum energy EmaxAnd the sum F of the braking forces which can be provided by the drive motor 7 and the bidirectional hydraulic motor 3mf+FbfLess than the target braking force F required for the axletDuring the operation, the vehicle control unit 16 controls the clutch 6 to be combined, controls the bidirectional hydraulic motor 3 to be switched to an oil pump mode, drives the motor 7 to work in a braking mode, provides a part of braking force, and provides the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+Fbf+FmmThe vehicle controller 16 controls the vehicle hybrid energy system integrating hydraulic power and battery to enter a braking mode combining motor braking, bidirectional hydraulic motor braking and mechanical braking.
If the rotating speed n of the driving motor 7 is less than the lowest power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy store 2cEqual to the highest energy EmaxAt the moment, the motor and the hydraulic system can not recover energy, the vehicle controller 16 controls the vehicle composite energy system integrating hydraulic power and the battery to enter a pure mechanical braking mode, and the braking force F of the axle is at the momenttIs provided entirely by the mechanical brake mechanism 10 to meet brake safety requirements.
As shown in fig. 1 and 4, a relationship curve between the target braking force and the brake pedal feedback force is obtained in advance through a test method and stored in the vehicle controller 16. When a vehicle enters a braking energy recovery mode and a bidirectional hydraulic motor and a motor are independently braked, a target pedal feedback force required to be provided by a braking system is obtained by inquiring a relation curve between a target braking force and a braking pedal feedback force on line, a braking assistance ratio is adjusted in real time through a braking assistance control unit 11, an actual pedal feedback force is measured in real time through a force sensor arranged at a braking pedal, the braking assistance ratio is adjusted through a closed-loop feedback of the braking assistance control unit 11, so that the feedback force acquired by the pedal position of a driver is consistent with the target feedback force during mechanical braking, a stable braking process is acquired, and meanwhile, the driver acquires a good braking feeling.

Claims (3)

1. A control method of a vehicle composite energy system integrating hydraulic power and a battery comprises a vehicle control unit, a hydraulic energy accumulator, an electro-hydraulic control module, a bidirectional hydraulic motor, a speed reducing mechanism, a clutch, a driving motor, a speed reducer, a battery, a motor controller, a battery management system, a brake power-assisted control unit and a CAN bus;
an output shaft of the bidirectional hydraulic motor is connected with one end of a rotor of the driving motor through a speed reducing mechanism and a clutch, and the other end of the rotor of the driving motor is connected with a wheel through a speed reducer; two oil inlets of the bidirectional hydraulic motor are respectively connected with the oil tank and the hydraulic energy accumulator, an oil inlet of the hydraulic energy accumulator is connected with an oil outlet of the electro-hydraulic control module, and an oil inlet of the electro-hydraulic control module is connected with an oil outlet of the bidirectional hydraulic motor; the control port of the bidirectional hydraulic motor is electrically connected with the electro-hydraulic control module;
the driving motor is electrically connected with the motor controller, the wheel is provided with a mechanical braking mechanism, and the mechanical braking mechanism is electrically connected with the brake power-assisted control unit; the battery is electrically connected with the battery management system; the electro-hydraulic control module, the clutch, the motor controller, the battery management system and the brake power-assisted control unit are connected in parallel on a CAN bus, and the CAN bus is electrically connected with the whole vehicle controller;
when a driver steps on an accelerator pedal, the vehicle enters a driving mode; the whole vehicle controller calculates the power P required by the driver according to the mass, the speed, the windward area, the flywheel rotational inertia, the wheel rotational inertia, the opening degree of an accelerator pedal and the opening degree change rate of the accelerator pedal of the whole vehicle; the vehicle control unit calculates the energy storage state E of the hydraulic energy storage according to the real-time pressure, the lowest pressure, the gas volume corresponding to the real-time pressure and the gas polytropic exponentc(ii) a The vehicle control unit passes through the energy storage state E of the hydraulic energy storage devicecCalculating the output driving power P of the bidirectional hydraulic motor according to the energy supply cycle time of the bidirectional hydraulic motor, the efficiency of the speed reducing mechanism and the efficiency of the speed reducerhyd(ii) a The vehicle control unit calculates the output driving power P of the driving motor according to the motor speed on the CAN bus by combining the motor speed-torque MAP stored in the vehicle control unit and the efficiency of the speed reducermo(ii) a The vehicle control unit is according to hydraulic pressure accumulator energy storage state EcPower required by driver P, output driving power P of bidirectional hydraulic motorhydOutput drive power P of drive motormoSelecting and controlling a driving mode;
when a driver steps on a brake pedal, the vehicle enters a brake energy recovery mode; the vehicle brake power-assisted control unit calculates the target brake force F of the driver on the axle where the driving motor and the bidirectional hydraulic motor are positioned through the opening degree signal of the brake pedal on the CAN bus, the distance from the front axle to the mass center, the automobile axle distance and the whole automobile masst(ii) a Calculating the energy storage state E of the hydraulic energy storage according to the real-time pressure of the hydraulic energy storage, the gas volume corresponding to the lowest pressure and the gas polytropic exponentc(ii) a The vehicle control unit passes through the energy storage state E of the hydraulic energy storage devicecCalculating the braking force F provided by the bidirectional hydraulic motor according to the energy supply cycle time of the bidirectional hydraulic motor, the center speed of the tire, the efficiency of the speed reducing mechanism and the efficiency of the speed reducerbf(ii) a According to the current motor rotating speed signal on the CAN bus, the braking which CAN be provided by the driving motor is obtained through the motor rotating speed-torque MAP stored in the vehicle control unit and by combining the transmission ratio, the reducer efficiency and the tire radiusForce Fmf(ii) a The vehicle control unit brakes F according to the target brake force of the drivertThe braking force F provided by the bidirectional hydraulic motorbfThe driving motor can provide braking force FmfAnd the energy storage state E of the hydraulic energy storage devicecSelecting and controlling a braking energy recovery mode;
the specific method for selecting and controlling the braking energy recovery mode comprises the following steps:
after the vehicle enters a braking energy recovery mode, if the rotating speed n of the driving motor is less than the lowest power generation threshold rotating speed n of the motor in an axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the bidirectional hydraulic motor can provide braking force FbfNot less than target braking force F required for the axletWhen the vehicle is in a braking mode, the vehicle controller controls the clutch to be combined and controls the bidirectional hydraulic motor to be switched into an oil pump mode, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and a battery to enter the bidirectional hydraulic motor braking mode;
in the axle connected with the driving motor and the bidirectional hydraulic motor together, if the rotating speed n of the driving motor is less than the minimum power generation threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy storecLess than maximum energy EminAnd the bidirectional hydraulic motor can provide braking force FbfLess than the target braking force F required for the axletWhen the vehicle is in a hydraulic braking mode, the vehicle controller controls the clutch to be combined and controls the bidirectional hydraulic motor to be switched to an oil pump mode, the bidirectional hydraulic motor provides a part of braking force, and the rest required braking force is provided by a vehicle mechanical braking system;
if the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd the driving motor can provide braking force FmfNot less than the target braking force required for the axle,the bidirectional hydraulic motor cannot provide braking force, and the whole vehicle controller controls the clutch to be separated; at the moment, the braking force is provided by the driving motor independently, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a motor independent braking mode;
if the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd the braking force F provided by the driving motormfLess than the target braking force F required for the axletWhen the vehicle is in a driving state, the vehicle controller controls the clutch to be disengaged; the driving motor works in a braking mode to provide a part of braking force and the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+FmmThe vehicle controller controls a vehicle composite energy system integrating hydraulic power and a battery to enter a braking mode combining motor braking and mechanical braking;
if the rotating speed n of the driving motor is not less than the minimum power generation threshold rotating speed n of the motor in the axle connected with the driving motor and the bidirectional hydraulic motor togetherminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the sum F of the braking forces provided by the driving motor and the bidirectional hydraulic motormf+FbfNot less than target braking force F required for the axletWhen the vehicle is in a braking mode, the vehicle controller controls the clutch to be combined and controls the bidirectional hydraulic motor to be switched into an oil pump mode, the braking force of the axle is provided by the driving motor and the bidirectional hydraulic motor together, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter the braking mode combining the braking of the bidirectional hydraulic motor and the braking of the motor;
in the axle connected with the electric motor and the bidirectional hydraulic motor in a driving way, if the rotating speed n of the driving electric motor is not less than the minimum power generation threshold rotating speed n of the electric motorminEnergy storage state E of the hydraulic energy storecLess than maximum energy EmaxAnd the sum F of the braking forces provided by the driving motor and the bidirectional hydraulic motormf+FbfLess than the target braking force F required for the axletWhen the vehicle controller controls the clutch to be combined, the bidirectional hydraulic motor is controlled to be switched into the oil pump mode, the driving motor works in the braking mode, the two motors provide part of braking force, and the rest required braking force FmmProvided by a mechanical braking system of the vehicle, i.e. Ft＝Fmf+Fbf+FmmThe vehicle controller controls a vehicle composite energy system integrating hydraulic power and a battery to enter a braking mode combining motor braking, bidirectional hydraulic motor braking and mechanical braking;
in the axle connected with the driving motor and the bidirectional hydraulic motor together, if the rotating speed n of the driving motor is less than the lowest generating threshold rotating speed n of the motorminEnergy storage state E of the hydraulic energy storecEqual to the highest energy EmaxAnd at the moment, the driving motor and the hydraulic energy accumulator can not recover energy, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to enter a pure mechanical braking mode.
2. The control method of the hybrid energy system of the vehicle integrating hydraulic power and the battery according to claim 1, wherein the specific method for selecting and controlling the driving mode is as follows:
if the energy E of the hydraulic accumulatorcLess than the minimum energy EminAt the moment, the vehicle controller controls the clutch to be disconnected and starts the driving motor, and the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to be driven in an electric driving mode;
if the energy E of the hydraulic accumulatorcNot less than the minimum energy Emin(ii) a If the power P required by the driver is not more than the output driving power P of the bidirectional hydraulic motorhydThe vehicle controller controls the clutch to be combined, controls the bidirectional hydraulic motor to be switched into a motor mode, and controls the vehicle composite energy system integrating hydraulic power and the battery to be driven in a hydraulic driving mode;
if the energy E of the hydraulic accumulatorcNot less than the minimum energy EminAt this time, if the driver demand power P is greater than the bidirectional powerOutput drive power P of hydraulic motorhydAnd the vehicle control unit controls the clutch to be combined, controls the bidirectional hydraulic motor to be switched into a motor mode, and simultaneously controls the driving motor to start, so that the sum of the power of the driving motor and the output driving power of the bidirectional hydraulic motor is equal to the power required by the driver, namely P is Phyd+PmoAnd the vehicle controller controls the vehicle composite energy system integrating hydraulic power and the battery to perform hybrid driving by adopting hydraulic power and electric power.
3. The control method of the hybrid energy system of the vehicle integrating hydraulic power and a battery according to claim 1, characterized in that: the method comprises the steps of obtaining a relation curve between target braking force and brake pedal feedback force in advance through tests, storing the relation curve in a vehicle controller, enabling a vehicle to enter a braking energy recovery mode, obtaining the target pedal feedback force required by a braking system by inquiring the relation curve between the target braking force and the brake pedal feedback force when a bidirectional hydraulic motor or a driving motor brakes alone, adjusting the braking assistance ratio in real time through a braking assistance control unit, measuring actual pedal feedback force in real time through a force sensor arranged at a brake pedal, adjusting the braking assistance ratio through closed-loop feedback of the braking assistance control unit, and enabling the feedback force obtained at the pedal position of a driver to be consistent with the target feedback force during mechanical braking so as to obtain a stable braking process.
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