A parallel hybrid tractor motor parameter matching method

Abstract

The application provides a motor parameter matching method for a parallel hybrid tractor, which establishes a functional relationship between brake recovery energy and peak torque under a specific working condition for a hybrid power system, matches motor parameters from the perspective of overall vehicle benefits, establishes a quantitative relationship between benefits and peak torque, and thus can quantitatively calculate optimal motor parameters. peak ; b calculates a peak torque T peak and a peak power P peak lower limit according to vehicle power requirements; c selects a common working condition of the tractor, calculates a relationship between motor recovery energy Ebrk and motor peak power and peak torque: E brk =f(P peak ,T peak ); d establishes a functional relationship between motor peak power and peak torque: P peak =f(T peak ); and e obtains a relationship between motor recovery energy and peak torque by combining c and d.

Description

Technical Field

[0001] This invention relates to the technical field of motor parameter matching, specifically to a method for matching motor parameters in a parallel hybrid tractor. Background Technology

[0002] Tractor trucks, as the main vehicle type for high-speed transportation, consume a large amount of fuel. Reducing the energy consumption of tractor trucks is of great significance. Currently, a relatively effective energy-saving method is to use a hybrid power system. Depending on the location of the electric motor, hybrid power systems can be divided into P0, P1, P2, P3, P4, PS, and other configurations. The most suitable configuration for tractor trucks is the P2 configuration, also known as the parallel hybrid power system (see...). Figure 1 However, how to match the motor parameters so that the hybrid system can meet the performance requirements of the whole vehicle, reduce energy consumption, and not increase the cost too much is the key issue in the development and application of hybrid tractor vehicles. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for matching motor parameters in a parallel hybrid tractor. For hybrid power systems, it establishes a functional relationship between regenerative braking energy and peak torque under specific operating conditions, matching motor parameters from the perspective of overall vehicle benefits. This establishes a quantitative relationship between benefits and peak torque, thereby enabling the quantitative calculation of optimal motor parameters.

[0004] A method for matching motor parameters of a parallel hybrid tractor, characterized by comprising the following steps:

[0005] a. Calculate the peak torque T based on the configuration constraints. peak Upper limit;

[0006] b. Calculate the peak torque T based on the vehicle's power requirements. peak and peak power P peak Lower limit;

[0007] c. Select the commonly used operating conditions of the tractor, and calculate the motor's recovered energy Ebrk and peak power, peak value...

[0008] Torque Relationship: E brk =f(P peak ,T peak );

[0009] d. Establish the functional relationship between the peak power and peak torque of the tractor motor:

[0010] P peak =f(T) peak )

[0011] By combining e with c and d, we can obtain the relationship between the motor's recovered energy and peak torque:

[0012] f fits the above relationship within the boundary range calculated in steps a and b, establishing a function E of the motor's recovered energy and peak torque. brk (T peak );

[0013] The electric motor recovers energy and converts it into mechanical energy, replacing the engine's output. Therefore, the reduction in fuel consumption per 100 kilometers due to energy recovery is approximately...

[0014] Δfuel=E brk (T peak )η br η cha η dis η dr b e / ρ fuel

[0015] In the formula, η br η cha η dis η dr b e ρ fuel In order, they are: motor system braking efficiency, battery charging efficiency, battery discharging efficiency, motor system drive efficiency, engine specific energy consumption, and fuel density;

[0016] h is given the driving range S and fuel price p when evaluating the overall vehicle profitability. fuel The cost reduction ΔC resulting from energy recovery fuel for:

[0017]

[0018] i. Establish a functional relationship between the increased system cost and the peak torque of the motor: C add =f(T) peak );

[0019] After integrating steps h and i, the overall benefit of the vehicle is ΔC. fuel -C add Treating this as a function of the motor's peak torque, we can find the extreme points of the function to obtain the optimal motor peak torque. Combining this with step d, we can further obtain the optimal motor peak power.

[0020] Its further features are:

[0021] In step a, the motor torque should not exceed the maximum input torque limit of the gearbox, i.e.

[0022] T peak ≤T gb_max ;

[0023] In the formula, Tpeak T represents the peak torque of the motor, in Nm. gd_max This is the maximum input torque limit for the transmission.

[0024] In step b, the peak torque and power of the motor should meet the requirements of the vehicle to start and accelerate to the minimum stable speed on flat roads and common slopes.

[0025] The motor torque and power required to start on a slope with gradient α are:

[0026]

[0027] P peak ≥T peak N min / 9550

[0028] In the formula,

[0029] F0, F1, and F2 are the constant, linear, and quadratic terms of the driving resistance coefficient, respectively.

[0030] V min Minimum stable vehicle speed, in km / h;

[0031] M represents the vehicle mass, r wh The radius of the wheel is in meters (m).

[0032] i0 is the main reduction ratio, i g1 η is the first gear ratio of the gearbox, and η is the transmission efficiency.

[0033] P peak Peak power of the motor, in kW;

[0034] N min The minimum engine speed at which power can be stably output, measured in rpm.

[0035] In step c, the relationship between the motor's recovered energy Ebrk and the motor's peak power and peak torque is calculated. This relationship is summarized in a coordinate graph and ultimately obtained by constructing a function: E brk =f(P peak ,T peak ).

[0036] In step e, combining the data from steps c and d, a coordinate graph showing the relationship between the motor's recovered energy and peak torque is obtained and the relationship is established. Then, step f optimizes the range value, obtains a coordinate graph within the range value, and then fits it to establish a function E for the motor's recovered energy and peak torque. brk (T peak ).

[0037] By employing this invention, a functional relationship between regenerative braking energy and peak torque under specific operating conditions is established for hybrid power systems. Motor parameter matching is performed from the perspective of overall vehicle benefits, establishing a quantitative relationship between benefits and peak torque. This allows for the quantitative calculation of optimal motor parameters, enabling relatively quick and accurate calculation of the optimal peak torque and peak power of the motor for a parallel hybrid tractor. This provides guidance for the selection and design of hybrid tractors and has application value in promoting the industrialization of hybrid tractors. Attached Figure Description

[0038] Figure 1 This is a simplified schematic diagram of a parallel hybrid power configuration;

[0039] Figure 2 This is a schematic diagram of the CHTC-TT operating condition speed in a specific embodiment of the present invention;

[0040] Figure 3 For the present invention Figure 2 The relationship between recovered energy and peak torque and peak power under the operating conditions;

[0041] Figure 4 for Figure 2 The coordinate relationship between recovered energy and recovered torque under the operating conditions;

[0042] Figure 5 for Figure 2 The relationship graph of the fitting function under the working conditions. Detailed Implementation

[0043] A method for matching motor parameters of a parallel hybrid tractor, the parameters of which in a specific embodiment are shown in Table 1, and the driving resistance coefficient of the tractor are shown in Table 2:

[0044]

[0045]

[0046] Table 1

[0047]

[0048] Table 2

[0049] In a specific embodiment, the minimum speed at which the engine can stably output power is 800 rpm, and the tractor commonly uses a 4% gradient.

[0050] The specific implementation steps are as follows:

[0051] a. Calculate the peak torque T based on the configuration constraints. peak Upper limit;

[0052] b. Calculate the peak torque T based on the vehicle's power requirements. peak and peak power P peak Lower limit; obtained by combining steps a and b

[0053]

[0054] c Under CHTC-TT operating conditions (see...) Figure 2 The relationship between the recovered energy Ebrk of the motor and the peak power and peak torque of the motor is calculated and summarized in a coordinate graph. Figure 3 Ultimately, E is obtained through the construction function. brk =f(P peak ,T peak );

[0055] d. Considering the gearbox shift point is 1300 rpm, the commonly used range of motor speed is 1100-1300 rpm.

[0056] Taking an approximate average of 1200 rpm, the relationship between the motor's peak power and peak torque is as follows:

[0057] P peak ≈T peak / 7.96

[0058] Combining steps c and d, we obtain the coordinate graph showing the relationship between the motor's recovered energy and peak torque. Figure 4 :

[0059] f. Fit the above relationship within the boundary range calculated in steps a and b, and obtain the fitted coordinate relationship graph (see figure). Figure 5 Establish a function E for the motor's energy recovery and peak torque. brk (T peak );

[0060] The electric motor recovers energy and converts it into mechanical energy, replacing the engine's output. Therefore, the reduction in fuel consumption per 100 kilometers due to energy recovery is approximately...

[0061] Δfuel=E brk (T peak )η br η cha η dis η dr b e / ρ fuel

[0062] In the formula, η br η cha η dis η dr b e ρ fuelIn order, they are: motor system braking efficiency, battery charging efficiency, battery discharging efficiency, motor system drive efficiency, engine specific energy consumption, and fuel density;

[0063] h is given the driving range S and fuel price p when evaluating the overall vehicle profitability. fuel The cost reduction ΔC resulting from energy recovery fuel for:

[0064]

[0065] i. Establish a functional relationship between the increased system cost and the peak torque of the motor: C add =f(T) peak Including motor cost, motor controller cost, and battery cost, the functional relationship between cost and peak torque is as follows:

[0066]

[0067] The parameters in the formula for the whole vehicle are shown in Table 3:

[0068]

[0069]

[0070] Table 3

[0071] The overall revenue of the vehicle is calculated by combining (h) and (i), with the total revenue being ΔC. fuel -C add Treating this as a function of the motor's peak torque, we can find the extreme points of the function to obtain the optimal motor peak torque; combined with step d, we can obtain the optimal motor peak power, T. peak =1402.6 Nm.

[0072] This study establishes a functional relationship between regenerative braking energy and peak torque under specific operating conditions for hybrid power systems. By matching motor parameters from the perspective of overall vehicle benefits, a quantitative relationship between benefits and peak torque is established. This allows for the quantitative calculation of optimal motor parameters, enabling relatively quick and accurate calculation of the optimal peak torque and peak power of the motor for parallel hybrid tractor vehicles. This provides guidance for the selection and design of hybrid tractor vehicles and has application value in promoting the industrialization of hybrid tractor vehicles.

[0073] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0074] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method of matching parameters of an electric machine of a parallel hybrid tractor, characterized in that, It comprises the following steps: a depending on the configuration constraint, calculating the peak torque upper limit; b Peak torque is calculated according to the power demand of the whole vehicle and peak power Lower limit; c Select the common working condition of the tractor, calculate the relationship between the motor recovery energy Ebrk and the peak power and peak torque of the motor: ; d. Establishing the function relation of the peak power and peak torque of the tractor motor: e. Combining c and d, obtaining the relation of the motor energy recovery and peak torque: fThe above relationship is fitted within the boundary range calculated in steps a, b to establish a function of motor recovered energy and peak torque ; g. The motor energy recovery is finally converted into mechanical energy to replace the engine output, so the reduction of fuel consumption per 100 kilometers brought by the energy recovery is approximately In the formula, In order, motor system braking efficiency, battery charging efficiency, battery discharging efficiency, motor system driving efficiency, engine specific energy consumption, fuel density; h the driving distance at the time of evaluating the overall benefit of the vehicle and the fuel price the use cost reduction by the recovered energy is ； i The function relationship between the cost of the system and the peak torque of the motor: ; jComprehensive step h, i, the overall vehicle comprehensive income is The optimal motor peak torque is obtained by taking it as a function of the motor peak torque and solving the extreme point of the function. In combination with step d, the optimal motor peak power is further obtained.

2. The method of claim 1, wherein: In step a, the motor torque should not exceed the maximum input torque limit of the gearbox, i.e. ; wherein Tpeak is the peak torque of the electric machine in Nm; T gd_max Tmax is the maximum input torque limit of the gearbox.

3. The method of claim 1, wherein: In step b, the peak torque and power of the motor should meet the demand of the vehicle starting, accelerating and reaching the minimum stable speed on the flat road and the commonly used slope; The motor torque and power required to start on a ramp with a slope of 1: 10 is: In the formula, , , are constant term, linear term and quadratic term of the driving resistance coefficient, respectively; Minimum stable vehicle speed, in km / h; for the total vehicle mass, for the wheel radius in meters; is the main reduction ratio, is the gear 1 speed ratio of the gearbox, is the transmission efficiency; Ppk = peak power of motor, in kW; The minimum engine speed in rpm at which the engine is able to deliver stable power.

4. The method of matching parameters of an electric machine of a parallel hybrid tractor vehicle according to claim 3, characterized in that: In step c, the relationship between the motor recovered energy Ebrk and the peak power and peak torque of the motor is calculated, which is summarized in the form of a coordinate graph, and finally a function is constructed to obtain: .

5. The method of matching parameters of an electric machine of a parallel hybrid tractor vehicle according to claim 4, characterized in that: In step e, the data in steps c and d are combined to obtain a coordinate graph of the relationship between the motor energy recovery and the peak torque, a relationship is established, and then the range value is optimized through step f to obtain a coordinate relationship graph within the range value, and then fitting is performed to establish a function of the motor energy recovery and the peak torque .

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