A series hybrid power system for intelligent tractor and control method thereof

Abstract

The present invention discloses a series hybrid power system for an intelligent tractor and a control method thereof, comprising a diesel engine, a generator, a traction motor, a transmission, a PTO motor, a central transmission, a power battery and a DC / AC converter, wherein the output end of the diesel engine is mechanically connected to the input end of the generator, the output end of the generator is electrically connected to the input ends of the traction motor, the power battery and the PTO motor respectively, and the output end of the power battery is electrically connected to the input ends of the traction motor and the PTO motor respectively through a DC / AC converter. The present invention can determine the operating mode of the tractor according to the expected vehicle speed provided by the intelligent driving system, and provides different power supply modes under different operating modes, thereby improving the problems of poor emission performance and insufficient power of the tractor.

Description

Technical Field

[0001] The invention relates to a tractor, and in particular to a series hybrid power system for an intelligent tractor and a control method thereof. Background Art

[0002] As one of the important equipment of agricultural machinery, tractors are widely used in industrial and agricultural production and life. However, traditional tractors have problems such as high fuel consumption, single energy structure, and poor emission performance, which are not conducive to achieving the goals of energy saving, environmental protection, and high efficiency. In addition, since crude oil is a non-renewable resource and has low short-term supply elasticity, the oil price continues to rise, and the cost of using tractors is getting higher and higher. Based on the above background, the present invention hopes to design a series hybrid power system for intelligent tractors, which can achieve energy saving and emission reduction of tractors and reduce the cost of using tractors. Summary of the invention

[0003] The purpose of the present invention is to provide a series hybrid power system for an intelligent tractor and a control method thereof, which can not only achieve energy conservation and emission reduction of the tractor and reduce the use cost of the tractor, but also provide different power supply methods in different operating modes to meet the corresponding operating power requirements, solve the problem of insufficient power, and effectively solve the problems in the background technology.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a series hybrid power system for an intelligent tractor, comprising a diesel engine 1, a generator 2, a traction motor 3, a transmission 4, a PTO motor 5, a central transmission device 6, a power battery 10 and a DC / AC converter 16, wherein the output end of the diesel engine 1 and the input end of the generator 2 are mechanically connected so that the two constitute a diesel engine-generator set, the output end of the generator 2 is electrically connected to the input ends of the traction motor 3, the power battery 10 and the PTO motor 5, respectively, the output end of the power battery 10 is electrically connected to the input ends of the DC / AC converter 16 and the DC / DC converter 15, respectively, the output end of the DC / AC converter 16 is electrically connected to the input ends of the traction motor 3 and the PTO motor 5, the output end of the traction motor 3 is mechanically connected to the input end of the transmission 4, the output end of the transmission 4 is mechanically connected to the input end of the central transmission device 6 installed on the rear wheel axle, and the output end of the central transmission device 6 is mechanically connected to the rear wheel 7.

[0005] The intelligent tractor adopting the aforementioned series hybrid power system includes an intelligent driving system, which includes a low-voltage battery 11, a binocular camera 12, a laser radar 13, an industrial computer 14 and a DC / DC converter 15. The output end of the DC / DC converter 15 is electrically connected to the input end of the low-voltage battery 11, and the output end of the low-voltage battery 11 is electrically connected to the binocular camera 12, the laser radar 13, the electric steering power pump 9, the industrial computer 14, and the vehicle controller 8 respectively. The binocular camera 12 is connected to the industrial computer 14 through a CAN bus, the laser radar 13 is connected to the industrial computer 14 through Ethernet, and the industrial computer 14 and the vehicle controller 8 communicate data through UDP communication.

[0006] The intelligent tractor adopting the aforementioned series hybrid power system also includes a CAN bus communication system, that is, the vehicle controller 8 is connected to the diesel engine 1, the generator 2, the traction motor 3, the PTO motor 5, the electric steering power pump 9, the power battery 10, the low-voltage battery 11, the DC / DC converter 15, and the DC / AC converter 16 through the CAN bus.

[0007] A control method for a series hybrid power system for an intelligent tractor comprises the following steps:

[0008] S1: The intelligent driving system calculates the expected vehicle speed v and transmits the expected vehicle speed information to the vehicle controller 8;

[0009] S2: The vehicle controller 8 obtains the expected vehicle speed v and determines the working mode according to the expected vehicle speed v;

[0010] (1) If v>10 km / h, it is determined to be in transport operation mode. In this mode, the traction motor 3 operates alone. The vehicle controller 8 obtains the required power P of the traction motor 3. t , the real-time power consumption P of the low-voltage battery 11 l-bat , the SOC value of the power battery 10, the rated power P of the power battery 10 h-bat and the rated power P of the diesel engine-generator set e-g Then, perform the following power supply method:

[0011] When SOC>SOC low When P h-bat ≥P t +P l-bat , the power battery 10 supplies power to the traction motor 3; if P h-bat <P t +P l-bat , the vehicle controller controls the diesel engine-generator set to start, and the power battery 10 and the diesel engine-generator set jointly supply power to the traction motor 3;

[0012] When SOC≤SOClow When the power battery 10 stops supplying power to the traction motor 3, the vehicle controller controls the diesel generator set to start; if the diesel generator set supplies power to the traction motor 3 and the power battery 10; if the vehicle controller adjusts the overall machine demand power by reducing the vehicle speed, so that to ensure the normal driving of the tractor, where η is the charge and discharge efficiency of the power battery 10.

[0013] (2) If 0.5 < v < 10 km / h, it is determined as the rotary tillage operation mode. In this mode, the traction motor 3 and the PTO motor 5 operate together. The vehicle controller obtains the demand power P of the traction motor 3 t , the demand power P of the PTO motor 5 p , the actual consumption power P of the low-voltage battery 11 l-bat , the SOC value of the power battery 10, the rated power P of the power battery 10 h-bat and the rated power P of the diesel generator set e-g and then executes the following power supply method:

[0014] When SOC > SOC low , if P h-bat ≥ P t + P p + P l-bat , the power battery 10 supplies power to the traction motor 3 and the PTO motor 5; if P h-bat < P t + P p + P l-bat , the vehicle controller controls the diesel generator set to start, the power battery 10 supplies power to the PTO motor 5, and the diesel generator set supplies power to the traction motor 3;

[0015] When SOC ≤ SOC low , the power battery 10 stops supplying power to the traction motor 3 and the PTO motor 5, and the vehicle controller controls the diesel generator set to start; if the diesel generator set supplies power to the traction motor 3, the PTO motor 5 and the power battery 10; if the vehicle controller adjusts the overall machine demand power by reducing the vehicle speed, so that to ensure the normal driving of the tractor.

[0016] The beneficial effects of the present invention are as follows: the series hybrid power system for the intelligent tractor utilizes the expected vehicle speed provided by the intelligent driving system to divide the tractor into different operating modes, and provides different power supply methods in different operating modes, which not only improves the power but also reduces the use cost of the tractor; the diesel engine is only used for power generation, so it is smaller than the diesel engine of the traditional tractor, which reduces fuel consumption and can further reduce the use quality of the whole machine; the present invention is provided with two power sources, a diesel engine-generator set and a power battery, which improves the endurance of the tractor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic diagram of the topological structure of an intelligent tractor adopting a series hybrid power system of the present invention.

[0018] Figure 2 The figure is a schematic diagram of the overall flow of a control method for a series hybrid power system of the present invention.

[0019] [Reference Signs]

[0020] 1. Diesel engine, 2. Generator, 3. Traction motor, 4. Transmission, 5. PTO motor, 6. Central transmission, 7. Rear wheel, 8. Vehicle controller, 9. Electric power steering pump, 10. Power battery, 11. Low-voltage battery, 12. Binocular camera, 13. LiDAR, 14. Industrial computer, 15. DC / DC converter, 16. DC / AC converter. DETAILED DESCRIPTION

[0021] The technical solution proposed by the present invention is further described below in conjunction with the accompanying drawings.

[0022] Please refer to 1, which is a schematic diagram of the topological structure of an intelligent tractor in this embodiment. The intelligent tractor adopts the series hybrid power system proposed in the present invention, which includes: a diesel engine 1, a generator 2, a traction motor 3, a transmission 4, a PTO motor 5, a central transmission device 6, a power battery 10 and a DC / AC converter 16; the output end of the diesel engine 1 is mechanically connected to the input end of the generator 2, and the diesel engine is used as a prime mover to drive the generator to generate electricity, and the two together constitute a diesel engine-generator set; the output end of the generator 2 is electrically connected to the input ends of the traction motor 3, the power battery 10 and the PTO motor 5 respectively, the output end of the power battery 10 is electrically connected to the input ends of the DC / AC converter 16 and the DC / DC converter 15 respectively, the output end of the DC / AC converter 16 is electrically connected to the input ends of the traction motor 3 and the PTO motor 5 respectively, the output end of the traction motor 3 is mechanically connected to the input end of the transmission 4, the output end of the transmission 4 is mechanically connected to the input end of the central transmission device 6 installed on the rear wheel shaft, and the output end of the central transmission device 6 is mechanically connected to the rear wheel 7.

[0023] exist Figure 1 Based on the series hybrid system shown, the diesel engine 1 drives the generator 2 to generate electricity; the generator 2 supplies power to the traction motor 3, the power battery 10 and the PTO motor 5 respectively; the power battery 10 supplies power to the traction motor 3 and the PTO motor 5 respectively through the DC / AC converter 16, and the power battery 10 supplies power to the low-voltage battery 11 through the DC / DC converter 15.

[0024] See also Figure 1 In this embodiment, an intelligent tractor also includes an intelligent driving system, which includes: a low-voltage battery 11, a binocular camera 12, a laser radar 13 and an industrial computer 14; the output end of the DC / DC converter 15 is electrically connected to the input end of the low-voltage battery 11, and the output end of the low-voltage battery 11 is electrically connected to the binocular camera 12, the laser radar 13, the electric steering power pump 9, the industrial computer 14, and the vehicle controller 8 to supply power to the binocular camera, the laser radar, the electric steering power pump, the industrial computer, and the vehicle controller respectively. The binocular camera 12 is connected to the industrial computer 14 through a CAN bus, the laser radar 13 is connected to the industrial computer 14 through Ethernet (i.e., Ethernet), and the industrial computer 14 and the vehicle controller 5 communicate data through UDP communication.

[0025] See also Figure 1In this embodiment, an intelligent tractor further includes a CAN bus communication system, that is, the vehicle controller 8 is connected to the diesel engine 1, the generator 2, the traction motor 3, the PTO motor 5, the electric steering pump 9, the power battery 10, the low-voltage battery 11, the DC / DC converter 15 and the DC / AC converter 16 through the CAN bus for data information transmission.

[0026] See also Figure 2 ,exist Figure 1 Based on the series hybrid power system shown in the figure, the present invention also proposes a series hybrid power system control method for an intelligent tractor, comprising the following steps:

[0027] S1: The intelligent driving system calculates the expected vehicle speed v and transmits the expected vehicle speed information to the vehicle controller 8;

[0028] The binocular camera 12 collects image data information of the working environment and transmits the image data information to the industrial computer 14; the laser radar 13 collects point cloud data information of the working environment and transmits the point cloud data information to the industrial computer 14; the industrial computer 14 analyzes the point cloud data information and the image data information, and uses the motion planning algorithm to obtain the expected vehicle speed v.

[0029] S2: The vehicle controller 8 obtains the expected vehicle speed v and determines the working mode according to the expected vehicle speed v;

[0030] If v>10km / h, it is determined to be in transport operation mode, in which the traction motor 3 operates alone; the vehicle controller 8 calculates the required power P of the traction motor 3 according to the following formula t : v is the expected vehicle speed, is the acceleration, f is the rolling resistance coefficient, m is the mass of the tractor, g is the acceleration of gravity, α is the slope angle, C D is the tractor drag coefficient, A is the tractor frontal area, δ is the tractor mass conversion coefficient, η tm is the mechanical efficiency of the tractor transmission system; the vehicle controller reads the voltage U and current I transmitted from the power battery 10 to the low-voltage battery 11 in real time through the CAN bus, and the vehicle controller 8 calculates the real-time power consumption P of the low-voltage battery 11 according to the following formula l-bat :P l-bat =UI; At the same time, the vehicle controller 8 obtains the rated power P of the power battery 10 h-bat and the rated power P of the diesel engine-generator set e-g and obtain the SOC value of the power battery 10 through the CAN bus.

[0031] The vehicle controller 8 analyzes all the above data information (including the required power of the traction motor, the real-time power consumption of the low-voltage battery, the rated power of the power battery, the rated power of the diesel engine-generator set, and the SOC value of the power battery), and executes the following power supply methods:

[0032] When SOC > SOC low (SOC low is the SOC value of 20% of the fully charged state of the power battery), if P h-bat ≥ P t + P l-bat , the power battery 10 supplies power to the traction motor 3; if P h-bat < P t + P l-bat , the vehicle controller controls the diesel engine-generator set to start, and the power battery 10 and the diesel engine-generator set jointly supply power to the traction motor 3;

[0033] When SOC ≤ SOC low , the power battery 10 stops supplying power to the traction motor 3, and the vehicle controller controls the diesel engine-generator set to start; if the diesel engine-generator set supplies power to the traction motor 3 and the power battery 10; if the vehicle controller adjusts the overall machine required power by reducing the vehicle speed, so that to ensure the normal driving of the tractor, where η is the charge and discharge efficiency of the power battery 10.

[0034] If 0.5 < v < 10 km / h, it is determined as the rotary tillage operation mode. In this mode, the traction motor 3 and the PTO motor 5 operate together; the vehicle controller 8 calculates the required power P t of the traction motor 3 and the required power P p of the PTO motor 5 according to the following formula: v is the desired vehicle speed, is the acceleration, f is the rolling resistance coefficient, m is the operating mass of the tractor, g is the acceleration due to gravity, α is the slope angle, C D is the wind resistance coefficient of the tractor, A is the frontal area of the tractor, δ is the mass conversion coefficient of the tractor, η tm is the mechanical efficiency of the tractor driveline; P c is the power consumption for soil cutting, P th is the power consumption for soil throwing, P a is the power consumption for the forward movement of the rotary tiller, P re is the power consumption for overcoming the horizontal soil reaction force, η pmThe vehicle controller reads the voltage U and current I transmitted from the power battery 10 to the low-voltage battery 11 in real time through the CAN bus. The vehicle controller 8 calculates the real-time power consumption P of the low-voltage battery 11 according to the following formula: l-bat :P l-bat =UI. At the same time, the vehicle controller 8 obtains the rated power P of the power battery 10 h-bat and the rated power P of the diesel engine-generator set e-g and obtain the SOC value of the power battery 10 through the CAN bus.

[0035] After analyzing all the above data information (including the required power of the traction motor, the required power of the PTO motor, the real-time power consumption of the low-voltage battery, the rated power of the power battery, the rated power of the diesel engine-generator set, and the SOC value of the power battery), the vehicle controller 8 executes the following power supply mode:

[0036] When SOC>SOC low When P h-bat ≥P t +P p +P l-bat , the power battery 10 supplies power to the traction motor 3 and the PTO motor 5; if P h-bat <P t +P p +P l-bat , the vehicle controller controls the diesel engine-generator set to start, the power battery 10 supplies power to the PTO motor 5, and the diesel engine-generator set supplies power to the traction motor 3;

[0037] When SOC≤SOC low When the power battery 10 stops supplying power to the traction motor 3 and the PTO motor 5, the vehicle controller controls the diesel engine-generator set to start; if The diesel engine-generator set supplies power to the traction motor 3, the PTO motor 5 and the power battery 10; if The vehicle controller adjusts the power demand of the whole machine by reducing the vehicle speed. To ensure the normal driving of the tractor, where η is the charging and discharging efficiency of the power battery 10.

[0038] The parts not described in detail in this invention are prior art.

[0039] The above is only a preferred embodiment of the present invention and is not any form of limitation to the present invention. Although the present invention is described in detail with reference to the preferred embodiment, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A control method for a series hybrid power system for an intelligent tractor, characterized in that The following steps are involved: S1: The intelligent driving system calculates the expected vehicle speed v and transmits the expected vehicle speed information to the vehicle controller; S2: The vehicle controller obtains the expected vehicle speed v and determines the working mode according to the expected vehicle speed v: (1) If v>10 km / h, it is determined to be in transport operation mode. In this mode, the traction motor operates alone, and the vehicle controller obtains the required power P of the traction motor. t , Real-time power consumption of low-voltage battery P l-bat , SOC value of the power battery, rated power P of the power battery h-bat and the rated power P of the diesel engine-generator set e-g Then, perform the following power supply method: When SOC>SOC low When P h-bat ≥P t +P l-bat , the power battery supplies power to the traction motor; if P h-bat <P t +P l-bat , the vehicle controller controls the diesel engine-generator set to start, and the power battery and the diesel engine-generator set jointly supply power to the traction motor; When SOC≤SOC low When the power battery stops supplying power to the traction motor, the vehicle controller controls the diesel engine-generator set to start; if The diesel engine-generator set supplies power to the traction motor and power battery; if The vehicle controller adjusts the power demand of the whole machine by reducing the vehicle speed. To ensure the normal driving of the tractor, where η is the charging and discharging efficiency of the power battery; (2) If 0.5 < v < 10 km / h, it is determined as the rotary tillage operation mode. In this mode, the traction motor and the PTO motor operate together, and the vehicle controller obtains the required power P of the traction motor t , the required power P of the PTO motor p , the real-time consumption power P of the low-voltage battery l-bat , the SOC value of the power battery, the rated power P of the power battery h-bat and the rated power P of the diesel generator set e-g After that, the following power supply method is executed: When SOC>SOC low When P h-bat ≥P t +P p +P l-bat , the power battery supplies power to the traction motor and PTO motor; if P h-bat <P t +P p +P l-bat , the vehicle controller controls the diesel engine-generator set to start, the power battery supplies power to the PTO motor, and the diesel engine-generator set supplies power to the traction motor; When SOC≤SOC low When the power battery stops supplying power to the traction motor and PTO motor, the vehicle controller controls the diesel engine-generator set to start; if The diesel engine-generator set supplies power to the traction motor, PTO motor and power battery; if The vehicle controller adjusts the power demand of the whole machine by reducing the vehicle speed. To ensure the normal driving of the tractor, where η is the charging and discharging efficiency of the power battery; The control method is implemented based on a series hybrid power system for an intelligent tractor, the series hybrid power system comprising a diesel engine (1), a generator (2), a traction motor (3), a PTO motor (5), a power battery (10) and a DC / AC converter (16), the output end of the diesel engine (1) and the input end of the generator (2) being mechanically connected so that the two form a diesel engine-generator set, the output end of the generator (2) being electrically connected to the input ends of the traction motor (3), the power battery (10) and the PTO motor (5) respectively, the output end of the power battery (10) being electrically connected to the input ends of the DC / AC converter (16) and the DC / DC converter (15) respectively, and the output end of the DC / AC converter (16) being electrically connected to the input ends of the traction motor (3) and the PTO motor (5) respectively.

2. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that The specific process of step S1 is: the binocular camera collects image data information of the working environment and transmits the image data information to the industrial computer; the laser radar collects point cloud data information of the working environment and transmits the point cloud data information to the industrial computer; the industrial computer analyzes the point cloud data information and image data information, and uses the motion planning algorithm to obtain the expected vehicle speed v.

3. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that In step S2, the required power P of the traction motor in the transport operation mode is t The calculation formula is: v is the expected vehicle speed, is the acceleration, f is the rolling resistance coefficient, m is the mass of the tractor, g is the acceleration of gravity, α is the slope angle, C D is the tractor drag coefficient, A is the tractor frontal area, δ is the tractor mass conversion coefficient, η tm is the mechanical efficiency of the tractor drive train.

4. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that In step S2, the required power P of the traction motor in the rotary tillage operation mode is t The calculation formula is: v is the expected vehicle speed, is the acceleration, f is the rolling resistance coefficient, m is the mass of the tractor, g is the acceleration of gravity, α is the slope angle, C D is the tractor drag coefficient, A is the tractor frontal area, δ is the tractor mass conversion coefficient, η tm is the mechanical efficiency of the tractor drive train; Required power P of the PTO motor p The calculation formula is: P c is the power consumption of soil cutting, P th is the power consumption of soil throwing, P a is the forward power consumption of the rotary tiller, P re The power consumption to overcome the horizontal reaction force of the soil, η pm It is the mechanical transmission efficiency of the rotary tiller.

5. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that In step S2, the real-time power consumption of the low-voltage battery P l-bat The calculation formula is: l-bat =UI, U and I are the voltage and current transmitted from the power battery to the low-voltage battery, respectively, which are read in real time by the vehicle controller through the CAN bus.

6. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that The output end of the traction motor (3) is mechanically connected to the input end of the transmission (4), the output end of the transmission (4) is mechanically connected to the input end of the central transmission device (6), and the output end of the central transmission device (6) is mechanically connected to the rear wheel (7).

7. A control method for a series hybrid power system for an intelligent tractor according to claim 1, characterized in that The intelligent tractor adopting the series hybrid power system also includes an intelligent driving system, which includes a low-voltage battery (11), a binocular camera (12), a laser radar (13), an industrial computer (14) and a DC / DC converter (15). The output end of the DC / DC converter (15) is electrically connected to the input end of the low-voltage battery (11), and the output end of the low-voltage battery (11) is electrically connected to the vehicle controller (8), the electric power steering pump (9), the binocular camera (12), the laser radar (13), and the industrial computer (14). The eye camera (12) is connected to the industrial computer (14) via a CAN bus, the laser radar (13) is connected to the industrial computer (14) via Ethernet, the industrial computer (14) and the vehicle controller (8) perform data communication via UDP communication, and the vehicle controller (8) is connected to the diesel engine (1), the generator (2), the traction motor (3), the PTO motor (5), the electric steering pump (9), the power battery (10), the low-voltage battery (11), the DC / DC converter (15), and the DC / AC converter (16) via the CAN bus.

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