Hybrid power system efficiency optimization control method and system and computer storage medium

Abstract

The embodiment of the invention discloses a hybrid power system efficiency optimization control method and system and a computer storage medium, and the method comprises the steps: calculating the required power of an engine based on the preset theoretical power of a battery and the current required power of an output shaft of a vehicle; engine rotating speeds in a preset range are selected in sequence, and engine torques corresponding to the engine rotating speeds are determined in sequence; engine efficiency is obtained according to the effective fuel consumption rate corresponding to the engine torque, and the rotating speed and torque of the first motor and the second motor are determined according to the engine efficiency; obtaining the first efficiency of the first motor and the second efficiency of the second motor, and calculating the actual power of the battery according to the first efficiency and the second efficiency; calculating system efficiency based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power; and comparing the system efficiency corresponding to the rotating speed of each engine, and determining the optimal value of the system efficiency.

Description

TECHNICAL FIELD

[0001] Embodiments of the present specification relate to the technical field of automobile control, and particularly relate to a hybrid power system efficiency optimization control method and system and a computer storage medium. BACKGROUND

[0002] A hybrid electric vehicle uses an internal combustion engine and a motor as power devices, and through a control strategy, the two power devices are coordinated to reduce fuel consumption, save energy and reduce emissions. According to the power transmission route, hybrid electric vehicles can be divided into series, parallel and power split. For a series-parallel hybrid electric vehicle, a planetary gear train is generally used to realize the decoupling of the engine speed and torque and the wheel speed and torque, so that the engine works in the economic region. Compared with series and parallel hybrid power systems, power split can more flexibly adjust the output power of the engine and the drive motor according to the actual vehicle working condition.

[0003] A hybrid power system includes multiple power sources, and needs to optimize power distribution of the power sources through a power distribution control strategy, so as to obtain better vehicle fuel economy. The core problems to be solved in the development of the control strategy include power distribution between the engine and the battery in the hybrid power mode and determination of the engine operating point. The minimum power loss method, i.e., the system efficiency optimization, in the hybrid power system, since the energy comes from different energy sources and a combined drive system is used for driving, in the energy optimization design process, not only the best operating point of the engine should be considered, but also the system efficiency optimization. Since the input and output elements of the hybrid power system are variable, the difficulty of system efficiency analysis is increased. Based on the system efficiency optimization control model, the hybrid power system is taken as the research object, and the efficiency characteristics of the engine, the battery and the motor are used to find the system efficiency optimization value in the hybrid power mode, and then the power distribution between the engine and the battery and the engine operating point are optimized. SUMMARY

[0004] Therefore, embodiments of the present specification provide a hybrid power system efficiency optimization control method and system and a computer storage medium, which are used to solve the problems that the power control strategy in the prior art cannot achieve global system efficiency optimization and the passive control of the battery power leads to shortened service life.

[0005] Embodiments of the present specification adopt the following technical solutions:

[0006] The present specification provides a hybrid power system efficiency optimization control method, which comprises:

[0007] Based on the preset battery theoretical power and the current output shaft demand power of the vehicle, the engine demand power is calculated;

[0008] select engine speeds in a preset range in sequence, and determine engine torques corresponding to the engine speeds in sequence;

[0009] According to the effective fuel consumption rate corresponding to the engine torque, an engine efficiency is obtained, and the speeds and torques of the first motor and the second motor are determined according to the engine efficiency;

[0010] Based on the speeds and torques of the first motor and the second motor, a first efficiency of the first motor and a second efficiency of the second motor are obtained, so as to calculate a battery actual power according to the first efficiency and the second efficiency;

[0011] Based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, a system efficiency is calculated;

[0012] The system efficiencies corresponding to the engine speeds are compared, and an optimal value of the system efficiency is determined.

[0013] The embodiments of the present specification also provide a hybrid power system efficiency optimization control system, which comprises:

[0014] A first calculation module calculates an engine demand power based on a preset battery theoretical power and a current output shaft demand power of a vehicle;

[0015] A first determination module selects engine speeds in a preset range in sequence, and determines engine torques corresponding to the engine speeds in sequence;

[0016] A second determination module obtains an engine efficiency according to an effective fuel consumption rate corresponding to the engine torque, and determines speeds and torques of a first motor and a second motor according to the engine efficiency;

[0017] An acquisition module obtains a first efficiency of the first motor and a second efficiency of the second motor based on the speeds and torques of the first motor and the second motor, so as to calculate a battery actual power according to the first efficiency and the second efficiency;

[0018] A second calculation module calculates a system efficiency based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power;

[0019] A comparison module compares the system efficiencies corresponding to the engine speeds, and determines an optimal value of the system efficiency.

[0020] The embodiment of the present specification also provides a computer storage medium comprising a program used in combination with an electronic device, the program being executable by a processor to complete the following steps:

[0021] Based on the preset battery theoretical power and the current output shaft demand power of the vehicle, the engine demand power is calculated;

[0022] The engine speed in the preset range is sequentially selected, and the engine torque corresponding to the engine speed is sequentially determined;

[0023] According to the effective fuel consumption rate corresponding to the engine torque obtained, the engine efficiency is obtained, and the speed and torque of the first motor and the second motor are determined according to the engine efficiency;

[0024] Based on the speed and torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, so as to calculate the battery actual power according to the first efficiency and the second efficiency;

[0025] Based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, the system efficiency is calculated;

[0026] The system efficiencies corresponding to the engine speeds are compared, and the optimal value of the system efficiency is determined.

[0027] The above at least one technical solution adopted by the embodiment of the present specification can achieve the following beneficial effects:

[0028] By optimizing from the perspective of energy flow of the entire powertrain rather than a single component, the oil-saving potential of the hybrid power system can be more fully tapped. In addition, by presetting the battery theoretical power, the battery is actively controlled to charge and discharge at a small power, avoiding the battery aging problem caused by high-power charging and discharging, thereby effectively prolonging the service life of the battery. And the engine speed in the preset range is sequentially selected, which is an iterative table lookup method. Compared with a complex global optimization algorithm, the calculation amount is moderate, and it is more suitable for real-time control on a vehicle-grade chip. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings described herein are used to provide further understanding of the embodiments of the present specification and constitute a part of the present specification. The illustrative embodiments of the present specification and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0030] Figure 1 A flowchart of a hybrid power system efficiency optimization control method provided by the embodiment of the present specification is shown;

[0031] Figure 2A structure diagram of a power split type hybrid power system corresponding to a hybrid power system efficiency optimization control method provided by an embodiment of the present specification is shown in FIG. 1.

[0032] Figure 3 A lever diagram in a hybrid mode corresponding to a hybrid power system efficiency optimization control method provided by an embodiment of the present specification is shown in FIG. 2.

[0033] Figure 4 A design flow diagram of a hybrid power system efficiency optimization control model corresponding to a hybrid power system efficiency optimization control method provided by an embodiment of the present specification is shown in FIG. 3.

[0034] Figure 5 A structure diagram of a hybrid power system efficiency optimization control system provided by an embodiment of the present specification is shown in FIG. 4.

[0035] Figure 6 A structure diagram of a computer storage medium corresponding to a hybrid power system efficiency optimization control method provided by an embodiment of the present specification is shown in FIG. 5. DETAILED DESCRIPTION

[0036] In the prior art, a rule-based control model is commonly used in engineering, that is, the power distribution of the engine and the battery and the engine operating point are determined according to the calibration data and the designer's experience with the vehicle speed and the driver's demand torque as inputs. Therefore, the control model is simple and easy to operate, has small calculation amount and good robustness.

[0037] However, the rule-based control model belongs to static control and cannot obtain optimal performance. The rules are completely dependent on the designer's experience, with the highest engine operating efficiency as the core, without considering the energy loss of the electric system, and cannot obtain the highest efficiency of the powertrain system, so the oil-saving potential of the hybrid power system cannot be maximized.

[0038] In addition, for the hybrid power system, energy comes from multiple energy sources. The idea of ignoring the energy loss of the battery and the motor and only considering the engine fuel consumption as the total energy consumption of the system is not comprehensive. When the engine works in the high-efficiency zone, the system efficiency may be low, which is caused by the battery or motor working in the low-efficiency zone.

[0039] In the existing control strategy, the battery power is usually determined passively by the vehicle demand power and the engine power, which may cause the battery to frequently perform high-power charging and discharging. High-power charging and discharging not only reduces the battery efficiency, but also is a key factor inducing battery aging, thereby shortening the service life of the battery.

[0040] Therefore, the embodiment of the present specification provides a hybrid power system efficiency optimization control method, system and computer storage medium. By optimizing from the perspective of energy flow of the entire powertrain rather than a single component, the oil saving potential of the hybrid power system can be fully tapped. In addition, by presetting the battery theoretical power, the battery is actively controlled to charge and discharge at a small power, avoiding the battery aging problem caused by high-power charging and discharging, thereby effectively prolonging the service life of the battery. And the engine speed in the preset range is selected in turn, which is an iterative table lookup method. Compared with a complex global optimization algorithm, the calculation amount is moderate, and it is more suitable for real-time control on a vehicle-grade chip.

[0041] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described below in conjunction with the specific embodiments of the present specification and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present specification, not all embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0042] The technical solutions provided by the embodiments of the present specification will be described in detail below in conjunction with the drawings.

[0043] As shown in the flowchart of the hybrid power system efficiency optimization control method provided by the embodiments of the present specification. Figure 1

[0044] In the embodiments of the present specification, the hybrid power system efficiency optimization control method can specifically include the following steps:

[0045] S101: calculating the engine demand power based on the preset battery theoretical power and the current output shaft demand power of the vehicle;

[0046] S103: selecting the engine speed in the preset range in turn, and determining the engine torque corresponding to the engine speed in turn;

[0047] S105: obtaining the engine efficiency according to the effective fuel consumption rate corresponding to the engine torque, and determining the speed and torque of the first motor and the second motor according to the engine efficiency;

[0048] S107: obtaining the first efficiency of the first motor and the second efficiency of the second motor based on the speed and torque of the first motor and the second motor, to calculate the battery actual power according to the first efficiency and the second efficiency;

[0049] S109: calculating the system efficiency based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency, and the battery actual power;​

[0050] S111: Compare the system efficiencies corresponding to each engine speed to determine the optimal value of the system efficiency.

[0051] In the embodiments of the present application, the battery is actively controlled to charge and discharge at a small power based on the preset battery theoretical power, and the system efficiency is optimized as the target to determine the system efficiency corresponding to each engine speed in the preset range in sequence, and the operating point of the engine and the motor is dynamically optimized by an iterative algorithm, which comprehensively considers the efficiency coupling relationship of the engine, the battery and the motor, can significantly improve the fuel economy of the vehicle under the premise of ensuring the power performance, and effectively prolong the service life of the battery.

[0052] As an application embodiment of the present application, for the step S101, the engine demand power is calculated based on the preset battery theoretical power and the current output shaft demand power of the vehicle, which can specifically include:

[0053] The output shaft demand power is calculated according to the current output shaft speed and the output shaft torque;

[0054] The engine demand power is calculated based on the battery theoretical power and the output shaft demand power.

[0055] In the embodiments of the present application, the vehicle controller (VCU) can continuously collect the output shaft speed and the output shaft torque through sensors, and calculate the output shaft demand power.

[0056] Specifically, the output shaft demand power can be calculated according to the following formula (1):

[0057]

[0058] Wherein, P Out (i,j) is the output shaft demand power, n Out (i) is the output shaft speed, T Out (j) is the output shaft torque, i and j are the arrangement numbers, i = 1 … n, j = 1 … m.

[0059] Further, the engine demand power can be calculated according to the following formula (2):

[0060] P Eng (i,j) = P Out (i,j) + |P BatSet | Formula (2)

[0061] Wherein, P Eng (i,j) is the engine demand power, and P BatSet is the preset battery theoretical power.

[0062] In the embodiments of the present application, the preset battery theoretical power is intended to control the battery to perform low-power charging and discharging.

[0063] As an application embodiment of the present application, for the step S103, engine speeds in a preset range are sequentially selected, and engine torques corresponding to the engine speeds are sequentially determined, which can be calculated according to the following formula (3):

[0064]

[0065] wherein T Eng (i,j,m) is the engine torque, n Eng (m) is the engine speed, m is the arrangement serial number, and m = 1 … n.

[0066] In the embodiments of the present application, the preset range is in the feasible range of the engine speed, different engine speeds in the preset range are iteratively selected, different engine torques corresponding to the different engine speeds are obtained, different parameters can be obtained in the subsequent process, and finally different system efficiencies are calculated. By comparing the system efficiencies, the optimal value of the system efficiency can be selected.

[0067] As an application embodiment of the present application, for the step S105, the engine efficiency is obtained according to the obtained effective fuel consumption rate corresponding to the engine torque, and the speeds and torques of the first motor and the second motor are determined according to the engine efficiency, which can specifically include:

[0068] The effective fuel consumption rate corresponding to the engine torque is obtained by interpolating the universal characteristic table of the engine;

[0069] The engine efficiency is calculated based on the effective fuel consumption rate;

[0070] The speeds and torques of the first motor and the speeds and torques of the second motor are respectively determined according to the engine efficiency.

[0071] In the embodiments of the present application, the universal characteristic table is a numerical table generated by the engine through bench testing in the laboratory to measure the complete data of the engine in the entire working range. The core function of the universal characteristic table is that for any engine working point (i.e. a specific speed and torque combination), the corresponding fuel consumption rate can be found on the table.

[0072] For example, the process of table lookup can be that when the control algorithm determines a target engine working point (speed = 2000 rpm, torque = 150 Nm), the ECU will immediately search for the fuel consumption rate value corresponding to the (2000, 150) coordinate in the preset table.

[0073] During the testing process, it is impossible to obtain data for every possible combination of speed and torque. Tests are always conducted at intervals; for example, the speed may be measured every 100 rpm, and the torque may be measured every 10 Nm.

[0074] In this case, the universal characteristic table may not contain the fuel consumption rate value corresponding to the target engine operating point.

[0075] At this point, interpolation is needed to estimate the fuel consumption rate corresponding to the target engine operating point. Interpolation is a kind of "based guess". Based on the surrounding known data points, mathematical methods (such as linear interpolation and bilinear interpolation) are used to estimate the value of the intermediate point in order to improve accuracy. Estimation is performed between known data points to obtain smooth and continuous data for any operating point.

[0076] Furthermore, the engine efficiency is calculated based on the effective fuel consumption rate, specifically according to the following formulas (4) and (5):

[0077] b e =f(n) Eng T Eng ) Formula (4)

[0078]

[0079] Among them, b e η is the engine's effective fuel consumption rate. Eng For engine efficiency; H u It has the low calorific value of diesel fuel.

[0080] Furthermore, the speed and torque of the first motor and the speed and torque of the second motor are determined according to the engine efficiency, and can be calculated according to the following formulas (6) to (8):

[0081] n E1 =n Eng ·(1-i 01 )+n Out ·i 01 Formula (6)

[0082] n E2 =n Eng ·(1-i 02 )+n Out ·i 02 Formula (7)

[0083]

[0084] Where, n E1n is the rotational speed of the first motor E2 T is the rotational speed of the second motor E1 T is the torque of the first motor E2 i is the torque of the second motor 01 and i 02 are the gear ratios of the first planetary gear set PG1 and the second planetary gear set PG2, respectively; J E1 , J Eng , J E2 are the moments of inertia of the first motor, the engine, and the second motor, respectively; J S1 , J C , J S2 are the moments of inertia of the sun gear S1, the carrier C, the output shaft, and the sun gear S2, respectively; α C and α Out are the angular accelerations of the carrier C and the output shaft, respectively.

[0085] In the embodiments of the present application, the torque of the engine is transmitted to the carrier, and in the steady state, the angular acceleration of each shaft is zero, so the rotational speed n E1 (i,j,m) and the torque T E1 (i,j,m) of the first motor and the rotational speed n E2 (i,j,m) and the torque T E2 (i,j,m) of the second motor can be calculated using the above formulas (6) to (8), respectively.

[0086] As an application embodiment of the present application, for the step S107, based on the rotational speed and torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, which can specifically include:

[0087] Based on the rotational speed and torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained by interpolating the efficiency table of the motor.

[0088] In the embodiments of the present application, the efficiency table of the motor and the universal characteristic table have the same principle, and are both obtained by experiments in advance, and the corresponding motor efficiency can be directly obtained according to the rotational speed and torque of the motor, which will not be described here.

[0089] Specifically, the first efficiency η E1 (i,j,m) of the first motor and the second efficiency η E2 (i,j,m) of the second motor can be obtained according to the following formulas (9) and (10):

[0090] η E1 = f(n E1 , T E1 ) formula (9)

[0091] η E2 = f(n E2 , T E2 ) Formula (10)

[0092] Further, the battery actual power is calculated according to the first efficiency and the second efficiency, and specifically, the calculation can be performed according to the following formula (11):

[0093]

[0094] wherein P BatAct (i,j,m) is the battery actual power, when n E1 ·T E1 > 0, t1 = 1, otherwise, t1 = -1, when n E2 ·T E2 > 0, t2 = 1, otherwise, t2 = -1.

[0095] As an application example of the present specification, for the step S109, the system efficiency is calculated based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, and specifically, the calculation can be performed according to the following formula (12) and formula (13):

[0096] In the driving state,

[0097]

[0098] In the braking state,

[0099] wherein η S is the system efficiency, P Out is the output shaft power, P Eng is the engine power, P Bat > 0 indicates that the battery is discharging, and P Bat < 0 indicates that the battery is charging.

[0100] In the present specification embodiment, since the input and output of the power split type hybrid power system energy are variable, this increases the complexity of the system efficiency analysis. The system contains the engine, the battery and the hybrid transmission, and the mathematical model of the system efficiency is mainly established by analyzing the energy flow direction. In the driving state, when the battery power is greater than zero, the system has two power sources of the engine and the battery; when the battery power is less than zero, the system has only one power source of the engine, and the battery is as a load; in the braking state, the battery is as a load, and the influence of the transmission mechanical efficiency is ignored.

[0101] As an application example of the present specification, for the step S111, the optimal value of the system efficiency is determined by comparing the system efficiencies corresponding to the engine speeds, comprising:

[0102] The optimal value of the system efficiency under the output shaft speed and torque is determined by iterative calculation and a maximum value function.

[0103] Specifically, the calculation can be performed according to the following formula (14):

[0104] η SOpt (i,j) = max{η S (i,j,1), η S (i,j,2),..., η S (i,j,m_max)} formula (14).

[0105] In the embodiment of the present specification, the engine in the hybrid mode is connected to the planet carrier through a clutch, and in order to prolong the service life of the battery, it is actively charged and discharged at a small power, so the preset battery theoretical power P BatSet is set. For a given output shaft speed n Out (i) and torque T Out (j), the engine power is the sum of the absolute value of the output shaft power and the preset power of the battery, and if a given engine speed n Eng (m) is given, the engine torque and the speeds and torques of the two motors can be calculated, and the system efficiency η S is obtained. Within the upper and lower limits of the engine speed corresponding to the output shaft speed, the optimal value of the system efficiency under the output shaft speed and torque can be obtained by iterative calculation and a maximum value function.

[0106] Specifically, the calculation can be performed according to the following formula (15):

[0107] η SOpt (i,j) = maxη S (n Out (i), T Out (j), n Eng (m), P BaSet )

[0108] n EngLowLim ≤ n Eng (m) ≤ n EngUpLim

[0109] n E1Min ≤ n E1 (i,j,m) ≤ n E1Max

[0110] n E2Min ≤ n E2(i,j,m)≤n E2Max

[0111] 0≤|n E1 (i,j,m)-n E2 (i,j,m)|≤6000

[0112] T EngMin ≤T Eng (i,j,m)≤T EngMax

[0113] T E1Min ≤T E1 (i,j,m)≤T E1Max

[0114] T E2Min ≤T E2 (i,j,m)≤T E2Max

[0115] -11≤P BatSet ≤0

[0116] P BatSet ≤P BatAct (i,j,m)≤0 Formula (15)

[0117] Where, η SOpt (i,j) represents the optimal system efficiency; n out n E1 n Eng n E2 These represent the rotational speeds of the output shaft, the first motor E1, the engine, and the second motor E2, respectively; T out T E1 T Eng T E2 These represent the torques of the output shaft, the first motor E1, the engine, and the second motor E2, respectively; P BatSet Preset the battery power for hybrid mode; n EngLowLim and n EngUpLim These are the lower and upper limits of the engine speed corresponding to the output shaft speed, respectively; n E1Min and n E1Max These are the minimum and maximum speeds of the first motor E1, respectively; n E2Min and n E2Max These are the minimum and maximum speeds of the second motor E2, respectively; T EngMin and T EngMax These are the engine's minimum torque and maximum torque, respectively; T E1Min and T E1Max These are the minimum and maximum torques of the first motor E1, respectively; T E2Min and T E2MaxThese are the minimum and maximum torques of the second motor E2, respectively; P BatAct This represents the actual power of the battery.

[0118] The hybrid power system efficiency optimization control method provided in this specification optimizes the energy flow of the entire powertrain rather than individual components, thus fully tapping the fuel-saving potential of the hybrid power system. Furthermore, by pre-setting the theoretical battery power, it actively controls the battery to charge and discharge at low power, avoiding battery aging caused by high-power charging and discharging, thereby effectively extending battery life. The method also employs an iterative lookup table approach, sequentially selecting engine speeds within a preset range. Compared to complex global optimization algorithms, this approach has a moderate computational load and is more suitable for real-time control on automotive-grade chips.

[0119] It should be noted that the above-described specific hybrid power system efficiency optimization control method is merely a specific application embodiment and does not limit the scope of the embodiments in this specification. Other specific embodiments may also be included, which will not be elaborated here.

[0120] Based on the same inventive concept, this specification also provides specific application examples of the above-described hybrid power system efficiency optimization control method.

[0121] like Figure 2 The diagram shown is a structural schematic of a power-split hybrid power system corresponding to a hybrid power system efficiency optimization control method provided in an embodiment of this specification.

[0122] In the embodiments described in this specification, the power-split hybrid power system may specifically include a diesel engine, two electric motors E1 and E2 (capable of simultaneously performing electric and generator functions), a power-split device, a brake B1, and two clutches C0 and C1. The power-split device consists of a negative-ratio planetary gear set PG1 and a positive-ratio planetary gear set PG2. In the power-split hybrid power system, the planet carrier of PG1 is connected to the planet carrier of PG2, and the ring gear of PG1 is connected to the ring gear of PG2. For ease of description, C and R are used to represent the planet carrier and the ring gear, respectively; R is connected to the output shaft; E1 is connected to the sun gear S1 of PG1, and E2 is connected to the sun gear S2 of PG2; the engine is connected to C via C0 and to S2 via C1; B1 locks C.

[0123] For the hybrid working mode, the brake B1 and the clutch C1 are not working, the clutch C0 is combined, and the engine and the planet carrier C are connected. The mode is also the e-CVT mode, and the transmission ratio of the gearbox can be continuously changed. When the system works in the acceleration working condition, the motor E1 provides positive torque to quickly increase the engine speed, and when the system is in the high-speed stable working condition, E1 works in the power generation mode to charge the battery or power the motor E2. In addition, the engine torque and speed are decoupled from the wheel torque and speed by using the double star row, so that the engine works in the optimal economic zone.

[0124] As Figure 3 shown, a lever schematic diagram in the hybrid mode corresponding to the hybrid system efficiency optimization control method provided by the embodiment of the present specification.

[0125] It should be noted that the working points of the engine and the motor are in the respective external characteristic regions; the battery power is within the limited value; only the steady state is considered, so the angular acceleration of each axis on the equivalent lever diagram is zero; the absolute value of the speed difference of the two motors cannot exceed 6000 rpm, otherwise it will cause serious vibration and noise.

[0126] The power split hybrid system provided by the embodiment of the present specification not only can realize stepless change of the speed ratio, but also can control the distribution and use of the system power flow, and has the condition of controlling the system to work at the optimal point. By designing the efficiency optimization control model of the hybrid working mode of the system, the working points of the components in the working mode are operated in the region of the optimal system efficiency, and thus the fuel economy of the whole vehicle can be effectively improved.

[0127] Figure 4 The design process schematic diagram of the hybrid system efficiency optimization control model corresponding to the hybrid mode provided by the embodiment of the present specification.

[0128] In the embodiment of the present specification, first, the vehicle controller (VCU) continuously collects the output shaft speed and torque through the sensor, and calculates the output shaft demand power.

[0129] Then, the control system calls the preset battery theoretical power value, and calculates the engine demand power according to the above formula (2).

[0130] The battery theoretical power value can be a fixed small power value (such as 3kW) set for protecting the battery, or can be dynamically adjusted according to the current state of the battery (SOC), temperature and the like, which is not limited here.

[0131] Then, the core iterative optimization cycle is entered.

[0132] The system traverses all possible engine speeds within the allowed range with a certain step (e.g. 50rpm), and for each engine speed, the following procedures are performed in sequence:

[0133] The engine torque is calculated according to the above formula (3);

[0134] It is verified whether the engine operating point is within its external characteristic torque range, and if not, it is skipped;

[0135] The speeds and torques of the two motors E1 and E2 are calculated according to the planetary gear dynamics relationship (formula 6-8);

[0136] It is verified whether the speeds and torques of the two motors are within the allowed range, and whether the speed difference between the two is less than 6000rpm. If any of the conditions is not met, it is skipped;

[0137] If all constraints are met, the fuel consumption rate is obtained by looking up the engine universal characteristic map, and the engine efficiency is calculated; the efficiencies of the two motors are obtained by looking up the motor efficiency MAP;

[0138] The actual power of the battery is calculated according to formulas 9-11;

[0139] According to the direction of energy flow, the system efficiency at the current operating point is calculated using formula 12 or 13.

[0140] When all engine speed iterations are completed, the system uses the maximum function (e.g. formula 14) to screen out the optimal system efficiency value, and records the corresponding optimal engine speed, optimal engine torque, and optimal motor E1 and E2 torque instructions at this time.

[0141] Finally, the control system sends these optimal operating point instructions to the engine controller (ECU) and motor controller (MCU) to drive the components to operate in coordination, thereby achieving system efficiency optimization and battery power protection under the current working condition.

[0142] The specific implementation process of the embodiments of the present specification can refer to the respective implementation steps corresponding to the above embodiments, which will not be repeated here.

[0143] Based on the same inventive concept, the embodiments of the present specification also provide a hybrid power system efficiency optimization control system. As shown in Figure 5 , it is a structural schematic diagram of a hybrid power system efficiency optimization control system provided by the embodiments of the present specification.

[0144] Among them, the hybrid power system efficiency optimization control system can specifically include:

[0145] The first calculation module 501 calculates the engine demand power based on the preset battery theoretical power and the current output shaft demand power of the vehicle;

[0146] The first determining module 502 sequentially selects engine speeds in a preset range, and sequentially determines engine torques corresponding to the engine speeds;

[0147] The second determining module 503 obtains engine efficiencies according to the effective fuel consumption rates corresponding to the engine torques, and determines the speeds and torques of the first motor and the second motor according to the engine efficiencies;

[0148] The obtaining module 504 obtains the first efficiency of the first motor and the second efficiency of the second motor based on the speeds and torques of the first motor and the second motor, so as to calculate the actual battery power according to the first efficiency and the second efficiency;

[0149] The second calculating module 505 calculates the system efficiency based on the output shaft demand power, the engine demand power, the theoretical battery power, the engine efficiency and the actual battery power;

[0150] The comparing module 506 compares the system efficiencies corresponding to the engine speeds, and determines the optimal value of the system efficiency.

[0151] Based on the system, Figure 5 the embodiments of the present specification also provide some specific embodiments of the system, which are described below.

[0152] Further, the engine demand power is calculated based on the preset theoretical battery power and the current output shaft demand power of the vehicle, and the calculation includes:

[0153] The output shaft demand power is calculated according to the current output shaft speed and the output shaft torque of the vehicle;

[0154] The engine demand power is calculated based on the theoretical battery power and the output shaft demand power.

[0155] Further, the engine demand power is calculated according to the following formula:

[0156] P Eng (i,j)=P Out (i,j)+|P BatSet |

[0157] Wherein, P Eng (i,j) is the engine demand power, P Out (j,j) is the output shaft demand power, and P BatSet is the preset theoretical battery power.

[0158] Further, engine speeds in a preset range are sequentially selected, and engine torques corresponding to the engine speeds are sequentially determined, and the following formula is used for calculation:

[0159]

[0160] wherein, T Eng (i,j,m) is the engine torque, n Eng (m) is the engine speed, m is the arrangement number, m = 1 … n.

[0161] Further, according to the effective fuel consumption rate corresponding to the engine torque obtained, the engine efficiency is obtained, and the speeds and torques of the first motor and the second motor are determined according to the engine efficiency, which can specifically include:

[0162] The effective fuel consumption rate corresponding to the engine torque is obtained through the universal characteristic table interpolation of the engine;

[0163] The engine efficiency is calculated based on the effective fuel consumption rate;

[0164] The speeds and torques of the first motor and the second motor are respectively determined according to the engine efficiency.

[0165] Further, based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, the system efficiency is calculated, and the following formula and formula are used for calculation:

[0166] In the driving state,

[0167]

[0168] In the braking state,

[0169] wherein, η S is the system efficiency, P Out is the output shaft power, P Eng is the engine power, η Eng is the efficiency of the engine, P Bat > 0 indicates that the battery is discharging, P Bat < 0 indicates that the battery is charging.

[0170] Further, the system efficiencies corresponding to the engine speeds are compared to determine the optimal value of the system efficiency, which includes:

[0171] The optimal value of the system efficiency under the output shaft speed and torque is determined through iterative calculation and a maximum value function.

[0172] Further, the optimal value of the system efficiency under the output shaft speed and torque is determined, and is calculated according to the following formula:

[0173] η SOpt (i,j) = maxη S (n Out (i), T Out (j), n Eng (m), P BatSet )

[0174] n EngLowLim ≤ n Eng (m) ≤ n EngUpLim

[0175] n E1Min ≤ n E1 (i,j,m) ≤ n E1Max

[0176] n E2Min ≤ n E2 (i,j,m) ≤ n E2Max

[0177] 0 ≤ |n E1 (i,j,m) - n E2 (i,j,m)| ≤ 6000

[0178] T EngMin ≤ T Eng (i,j,m) ≤ T EngMax

[0179] T E1Min ≤ T E1 (i,j,m) ≤ T E1Max

[0180] T E2Min ≤ T E2 (i,j,m) ≤ T E2Max

[0181] -11 ≤ P BatSet ≤ 0

[0182] P BatSet ≤ P BatAct (i,j,m) ≤ 0

[0183] Wherein, η SOpt (i,j) is the optimal value of the system efficiency; n out , n E1 , n Eng , n E2 are the speeds of the output shaft, the first motor E1, the engine and the second motor E2 respectively; T out , T E1 , TEng , T E2 are the torques of the output shaft, the first motor E1, the engine, and the second motor E2, respectively; P BatSet is the preset power of the battery in the hybrid mode; n EngLowLim and n EngUpLim are the lower and upper limits of the engine speed corresponding to the output shaft speed, respectively; n E1Min and n E1Max are the minimum and maximum speeds of the first motor E1, respectively; n E2Min and n E2Max are the minimum and maximum speeds of the second motor E2, respectively; T EngMin and T EngMax are the minimum and maximum torques of the engine, respectively; T E1Min and T E1Max are the minimum and maximum torques of the first motor E1, respectively; T E2Min and T E2Max are the minimum and maximum torques of the second motor E2, respectively; P BatAct is the actual power of the battery.

[0184] The hybrid power system efficiency optimization control system provided by the embodiments of the present specification can more fully tap the oil-saving potential of the hybrid power system by optimizing from the perspective of the energy flow of the entire powertrain rather than a single component. In addition, by presetting the battery theoretical power, the battery is actively controlled to charge and discharge at a small power, thereby avoiding the battery aging problem caused by large power charging and discharging, and effectively prolonging the service life of the battery. Furthermore, the engine speed in the preset range is selected in sequence, and the iterative table lookup method is adopted. Compared with a complex global optimization algorithm, the calculation amount is moderate, and the real-time control on the automotive-grade chip is more suitable.

[0185] Based on the same inventive concept, the embodiments of the present specification also provide an electronic device including at least one processor and a memory. The memory stores a program and is configured to be executed by the at least one processor to perform the following steps:

[0186] Based on the preset battery theoretical power and the current output shaft demand power of the vehicle, the engine demand power is calculated;

[0187] The engine speed in the preset range is selected in sequence, and the engine torque corresponding to the engine speed is determined in sequence;

[0188] The engine efficiency is obtained according to the effective fuel consumption rate corresponding to the engine torque, and the speeds and torques of the first motor and the second motor are determined according to the engine efficiency;

[0189] Based on the rotation speed and the torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, so as to calculate the battery actual power according to the first efficiency and the second efficiency;

[0190] Based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, the system efficiency is calculated.

[0191] The system efficiencies corresponding to the engine rotation speeds are compared, and the optimal value of the system efficiency is determined.

[0192] The other functions of the processor can also refer to the content described in the above embodiments, which will not be repeated here.

[0193] Based on the same inventive concept, the embodiments of the present specification also provide a computer readable storage medium, comprising a program used in combination with an electronic device, and the program can be executed by a processor to complete the following steps:

[0194] Based on the preset battery theoretical power and the current output shaft demand power of the vehicle, the engine demand power is calculated.

[0195] The engine rotation speeds in a preset range are selected in sequence, and the engine torques corresponding to the engine rotation speeds are determined in sequence.

[0196] According to the effective fuel consumption rate corresponding to the engine torque, the engine efficiency is obtained, and the rotation speed and the torque of the first motor and the second motor are determined according to the engine efficiency.

[0197] Based on the rotation speed and the torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, so as to calculate the battery actual power according to the first efficiency and the second efficiency;

[0198] Based on the output shaft demand power, the engine demand power, the battery theoretical power, the engine efficiency and the battery actual power, the system efficiency is calculated.

[0199] The system efficiencies corresponding to the engine rotation speeds are compared, and the optimal value of the system efficiency is determined.

[0200] The other functions of the processor can also refer to the content described in the above embodiments, which will not be repeated here.

[0201] As shown in Figure 6 The embodiments of the present specification also provide a structural schematic diagram of a computer storage medium.

[0202] The systems, apparatuses, modules, or units disclosed in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0203] For the sake of description, the above apparatuses are described in various units respectively according to functions. Of course, the functions of the units can be implemented in one or more software and / or hardware in the implementation of the present application.

[0204] Those skilled in the art should understand that embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) containing computer-usable program code.

[0205] The present application is described with reference to the flowcharts and / or block diagrams of the methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce the functions described in the flowcharts and / or block diagrams for implementing the flows and / or blocks in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0206] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce the manufactured product including the instruction apparatus, which implements the flows and / or blocks in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0207] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 Figure 1

[0208] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0209] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) about which the processor can execute instructions. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, or other memory technologies, CD-ROM, digital versatile disc (DVD), or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to store information for access by a computing device. In no case does the medium include a transitory signal.

[0210] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EEPROM), flash memory or other memory technologies, compact disc read only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to store information that can be accessed by a computing device. According to the definition herein, computer readable media does not include transitory media such as modulated data signals and carrier waves.

[0211] It should also be noted that the terms "comprising," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0212] ​​The application can be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, and the like, that perform particular tasks or implement particular abstract data types. The application can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules can be located in local and remote computer storage media including memory storage devices.

[0213] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, the system embodiments are described simply because they are basically similar to the method embodiments, and the relevant parts can be referred to the description of the method embodiments.

[0214] The above only describes the embodiments of the application and is not intended to limit the application. The application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application shall be included in the protection scope of the claims of the application.

Claims

1. A hybrid system efficiency optimization control method characterized by, The hybrid power system efficiency optimization control method includes: Calculate the engine power requirement based on the preset theoretical battery power and the current output shaft power requirement of the vehicle. Select engine speeds within a preset range in sequence, and determine the engine torque corresponding to each engine speed in sequence; Based on the effective fuel consumption rate corresponding to the engine torque, the engine efficiency is obtained, and the speed and torque of the first motor and the second motor are determined based on the engine efficiency. Based on the rotational speed and torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, so as to calculate the actual power of the battery according to the first efficiency and the second efficiency; The system efficiency is calculated based on the output shaft power requirement, the engine power requirement, the battery theoretical power, the engine efficiency, and the battery actual power. By comparing the system efficiency corresponding to each of the engine speeds, the optimal value of the system efficiency is determined.

2. The method of claim 1, wherein, Based on the preset theoretical battery power and the vehicle's current output shaft power requirement, the engine power requirement is calculated, including: Calculate the required power of the output shaft based on the vehicle's current output shaft speed and output shaft torque; The engine power requirement is calculated based on the theoretical power of the battery and the power demand of the output shaft.

3. The method as described in claim 2, characterized in that, Calculate the engine's required power using the following formula: P Eng (i,j) = P Out (i,j) + |P BatSet | where P Eng (i,j) is the engine demand power, P Out (i,j) is the output shaft demand power, P BatSet is the preset battery theoretical power.

4. The method as described in claim 1, characterized in that, Select engine speeds within a preset range in sequence, and determine the engine torque corresponding to each engine speed in sequence, and calculate according to the following formula: where T Eng (i,j,m) is the engine torque, n Eng (m) is the engine speed, m is the rank number, m = 1...n.

5. The method as described in claim 4, characterized in that, Based on the obtained effective fuel consumption rate corresponding to the engine torque, the engine efficiency is obtained, and the speed and torque of the first motor and the second motor are determined based on the engine efficiency, including: The effective fuel consumption rate corresponding to the engine torque is obtained by interpolating the universal characteristics of the engine through a lookup table. The engine efficiency is calculated based on the effective fuel consumption rate. The speed and torque of the first motor and the speed and torque of the second motor are determined based on the engine efficiency.

6. The method as described in claim 5, characterized in that, Based on the output shaft power requirement, the engine power requirement, the battery theoretical power, the engine efficiency, and the battery actual power, the system efficiency is calculated according to the following formulas: In driving mode Under braking conditions, where η S is the system efficiency, P Out is the output shaft power, P Eng is the engine power, η Eng is the efficiency of the engine, P Bat > 0 indicates that the battery is discharging, P Bat < 0 indicates that the battery is charging.

7. The method as described in claim 1, characterized in that, Comparing the system efficiency corresponding to each of the engine speeds to determine the optimal value of the system efficiency includes: The optimal system efficiency at the output shaft speed and torque is determined through iterative calculation and a maximum value function.

8. The method as described in claim 7, characterized in that, The optimal system efficiency at the given output shaft speed and torque is determined by calculation using the following formula: η SOpt (i,j) = maxη S (n Out (i), T Out (j), n Eng (m), P BatSet ) n EngLowLim ≤n Eng (m)≤n EngUpLim n E1Min ≤n E1 (i,j,m)≤n E1Max n E2Min ≤n E2 (i,j,m)≤n E2Max 0 ≤ |n E1 (i,j,m)-n E2 (i,j,m)|≤6000 T EngMin ≤T Eng (i,j,m)≤T EngMax T E1Min ≤T E1 (i,j,m)≤T E1Max T E2Min ≤T E2 (i,j,m)≤T E2Max -11≤P BatSet ≤0 P BatSet ≤P BatAct (i,j,m)≤0 η SOpt (i,j) is the optimal value of system efficiency; n out , n E1 , n Eng , n E2 are the rotational speeds of the output shaft, the first motor E1, the engine, and the second motor E2, respectively; T out , T E1 , T Eng , T E2 are the torques of the output shaft, the first motor E1, the engine, and the second motor E2, respectively; P BatSet is the preset power of the battery in the hybrid mode; n ENgLowLim and n ENgUpLim are the lower and upper limits of the engine rotational speed corresponding to the output shaft rotational speed, respectively; n E1Min and n E1Max are the minimum and maximum rotational speeds of the first motor E1, respectively; n E2Min and n E2Max are the minimum and maximum rotational speeds of the second motor E2, respectively; T EngMin and T EngMax are the minimum and maximum torques of the engine, respectively; T E1Min and T E1Max are the minimum and maximum torques of the first motor E1, respectively; T E2Min and T E2Max are the minimum and maximum torques of the second motor E2, respectively; P BatAct is the actual power of the battery.

9. A hybrid power system efficiency optimization control system, characterized in that, The hybrid power system efficiency optimization control system includes: The first calculation module calculates the engine power requirement based on the preset theoretical battery power and the current output shaft power requirement of the vehicle. The first determining module sequentially selects engine speeds within a preset range and sequentially determines the engine torque corresponding to the engine speeds. The second determining module obtains the engine efficiency based on the effective fuel consumption rate corresponding to the engine torque, and determines the speed and torque of the first motor and the second motor based on the engine efficiency. The acquisition module acquires the first efficiency of the first motor and the second efficiency of the second motor based on the rotational speed and torque of the first motor and the second motor, so as to calculate the actual power of the battery based on the first efficiency and the second efficiency; The second calculation module calculates the system efficiency based on the output shaft power requirement, the engine power requirement, the battery theoretical power, the engine efficiency, and the battery actual power. The comparison module compares the system efficiency corresponding to each of the engine speeds to determine the optimal value of the system efficiency.

10. A computer storage medium comprising a program for use in conjunction with an electronic device, the program being executable by a processor to perform the following steps: Calculate the engine power requirement based on the preset theoretical battery power and the current output shaft power requirement of the vehicle. Select engine speeds within a preset range in sequence, and determine the engine torque corresponding to each engine speed in sequence; Based on the effective fuel consumption rate corresponding to the engine torque, the engine efficiency is obtained, and the speed and torque of the first motor and the second motor are determined based on the engine efficiency. Based on the rotational speed and torque of the first motor and the second motor, the first efficiency of the first motor and the second efficiency of the second motor are obtained, so as to calculate the actual power of the battery according to the first efficiency and the second efficiency; The system efficiency is calculated based on the output shaft power requirement, the engine power requirement, the battery theoretical power, the engine efficiency, and the battery actual power. By comparing the system efficiency corresponding to each of the engine speeds, the optimal value of the system efficiency is determined.

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