Super-compact wind power gear box transmission system configuration design method

Abstract

The invention provides an ultra-compact wind power gear box transmission system configuration design method which comprises the following steps: optimizing the volume of a wind power gear box to obtain a theoretical minimum value of the volume; according to the theoretical minimum value of the volume of the wind power gear box, optimizing the transmission ratio and the number of planet gears, and determining the number and the transmission ratio of the planet gears of each gear train when the volume of the wind power gear box is minimum; geometric design is conducted on the gear, and a gear parameter design result is obtained, specifically, basic parameters and an objective function of the geometric dimension of the planetary gear train gear are determined, constraint conditions of planetary gear train gear transmission are set, and according to the basic parameters and the objective function of the geometric dimension of the planetary gear train gear and the constraint conditions of planetary gear train gear transmission, the gear parameter design result is obtained. And optimizing the geometric dimension of the gear by using an improved multi-objective optimization genetic algorithm. The technical problem that in the prior art, design methods for the ultra-compact wind power gear box are deficient can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind power generation technology, in particular to a design method of an ultra-compact wind power gearbox transmission system configuration. BACKGROUND

[0002] In recent years, with the continuous development of large-scale wind turbine unit capacity, the excessive weight of the transmission chain not only raises the material cost and manufacturing cost of the whole machine, but also limits its power generation efficiency and reliability. In order to realize the lightweight of the transmission chain, it is required to design the wind turbine transmission chain into an ultra-compact structure under the premise of meeting the reliability.

[0003] For the wind turbine transmission chain, the gearbox is the core component connecting the main shaft and the generator, so the design optimization of the gearbox configuration is particularly important under the design concept of ultra-compact structure. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a design method of an ultra-compact wind power gearbox transmission system configuration to solve the technical problem of the lack of design methods for ultra-compact wind power gearboxes in the prior art.

[0005] The technical solution adopted by the present application is as follows: In a first aspect, a design method of an ultra-compact wind power gearbox transmission system configuration is provided, comprising the following steps: Optimizing the volume of the wind power gearbox to obtain a theoretical minimum value of the volume; According to the theoretical minimum value of the volume of the wind power gearbox, the transmission ratio and the number of planetary gears are optimized to determine the number of planetary gears and the transmission ratio of each stage gear train when the volume of the wind power gearbox is minimized; Geometrically designing the gears to obtain gear parameter design results, including: determining the basic parameters and objective functions of the geometric dimensions of the planetary gear train, setting the constraint conditions of the planetary gear train transmission, and using an improved multi-objective optimization genetic algorithm to optimize the geometric dimensions of the gears according to the basic parameters and objective functions of the geometric dimensions of the planetary gear train, combined with the constraint conditions of the planetary gear train transmission.

[0006] Further, optimizing the volume of the wind power gearbox to obtain a theoretical minimum value of the volume comprises: Determining the maximum tooth load strength factor; According to the maximum tooth load strength factor, calculating the volume of the sun gear, the volume of the planetary gear, and the volume of the inner ring gear; According to the volume of the sun gear, the volume of the planetary gear, and the volume of the inner ring gear, determining the volume of the wind power gearbox; Setting the boundary constraint conditions for the optimization of the volume of the wind power gearbox; Taking the volume of the wind turbine gearbox as the objective function, according to the boundary constraint condition of the volume optimization of the wind turbine gearbox, the genetic algorithm with the simulated annealing mechanism is used to optimize the volume of the wind turbine gearbox, and the theoretical minimum value of the volume is obtained.

[0007] Further, the maximum tooth load strength factor of the sun gear and the planetary gear is determined according to the tooth surface contact fatigue strength formula.

[0008] Further, the boundary constraint condition of the volume optimization of the wind turbine gearbox includes the lower limit and the upper limit of the gear ratio distribution of each stage of the three-stage planetary gear train, and also includes the upper limit and the lower limit of the number distribution of each stage of the three-stage planetary gear train.

[0009] Further, according to the theoretical minimum value of the volume of the wind turbine gearbox, the gear ratio and the number of planetary gears are optimized, including: under the same speed ratio and torque requirements, the more the number of primary planetary gears, the lighter the weight of the wind turbine gearbox; When the number of secondary planetary gears is 6, the relative volume of the wind turbine gearbox is the smallest.

[0010] Further, the basic parameters of the gear geometry include the number of teeth, the modulus, the pressure angle, the helix angle, the tooth width and the modification coefficient.

[0011] Further, the objective function of the gear geometry includes the total volume of each stage of the planetary gear train in the gear transmission system, the difference of the contact fatigue safety factor of each stage of the planetary gear train, and the difference of the bending fatigue safety factor of each stage of the planetary gear train.

[0012] Further, the constraint conditions of the planetary gear train transmission are set, including: The boundary constraint of the basic parameters of the gear geometry is set; The concentric condition constraint of the planetary gear transmission is set; The abutment condition constraint of the planetary gear transmission is set; The assembly constraint of each stage of the planetary gear train is set; The constraint condition of the meshing angle of the inner and outer meshing pairs in each stage of the planetary gear train is set; The constraint condition of the end face coincidence degree of the inner and outer meshing pairs of the planetary gear train is set; The constraint condition of the tooth width coefficient is set; The constraint condition of the contact fatigue strength safety factor and the bending fatigue strength safety factor of the planetary gear train is set; The constraint condition of the tooth root transition curve interference prevention of the sun gear and the outer meshing pair of the planetary gear, the constraint condition of the tooth root transition curve interference prevention of the inner tooth ring and the planetary gear, the constraint condition of the tooth profile prevention of overlapping interference, and the constraint condition of the modification coefficient limitation are set; The constraint condition of the addendum thickness of the center wheel and the planetary gear is set; The constraint condition of the planetary carrier deformation is set.

[0013] Further, the improved multi-objective optimization genetic algorithm comprises the following steps: According to the sample range specified by the constraint condition, generate the sample data of the standardized Latin hypercube sampling, and establish the initialized population; In the adaptive non-dominated sorting, the feasibility of the individual solution of the population sample is judged by the external point penalty function, and the corresponding constraint violation degree is calculated, the individual comparison criterion is sorted based on the deb, and the non-dominated solution set of different levels is established; According to the objective function of each level of the non-dominated solution set, the crowding degree of the individual of the corresponding level is calculated; The parent population suitable for breeding is generated from the initial population by tournament selection, the parent population is generated by simulated binary crossover and mutation to generate the offspring population, and the offspring population is combined to generate the new population; The adaptive non-dominated sorting and the calculation of the crowding degree are carried out for the new population generated by combination; According to the elite reservation strategy, the first N priority individuals are selected from the sorted new population to form the new population of the next generation; The population evolution algebra is set, when the set value is reached, the optimization process is terminated, otherwise the next optimization iteration is continued.

[0014] In the second aspect, a super-compact wind power gear box transmission system is provided, which is designed by using the configuration design method provided in the first aspect.

[0015] From the above technical solution, the beneficial technical effects of the present application are as follows: The super-compact wind power gear box transmission system configuration design method optimizes the gear box volume, transmission ratio and other parameters, provides the geometric design parameters of the gear box transmission system, realizes the significant reduction of the gear box volume and weight under the premise of ensuring the bearing capacity and reliability, reduces the transportation and installation cost, improves the power density and operation stability, and is especially suitable for space-limited, high-maintenance-cost offshore and large-scale onshore wind turbine BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual proportion.

[0017] Figure 1 It is a schematic diagram of the three-stage planetary gear train configuration in the embodiment of the present application; Figure 2 It is a schematic diagram of the genetic algorithm process with simulated annealing mechanism introduced in the embodiment of the present application; Figure 3 Figure for the influence of the number of primary planetary gears on the volume of the wind turbine gearbox in the embodiment of the present application; Figure 4 Figure for the influence of the number of secondary planetary gears on the volume of the wind turbine gearbox in the embodiment of the present application; Figure 5 Figure for the process of the improved multi-objective optimization genetic algorithm in the embodiment of the present application; Figure 6 Figure for the process of the configuration design method of the gearbox of the ultra-compact wind turbine generator system in the embodiment of the present application. DETAILED DESCRIPTION

[0018] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0019] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by the skilled person in the field to which the present application belongs.

[0020] EMBODIMENT The present embodiment provides a configuration design method of an ultra-compact wind turbine gearbox transmission system, comprising the following steps: S1, optimizing the volume of the wind turbine gearbox to obtain the theoretical minimum value of the volume For the transmission system of the ultra-compact wind turbine generator, it is required that the volume of the gearbox is as small as possible under the premise of meeting the reliability. In the operation process of the wind turbine gearbox, gear fatigue failure is the main failure mode, and among the entire planetary gear system, the sun gear is the most prone to contact fatigue failure. Therefore, in the preliminary conceptual design, the establishment of a suitable mathematical model directly determines the reliability of the wind turbine. Considering the requirements of wind turbine cost and reliability, the number of planetary gears at each level and the distribution of transmission ratio at each level are determined as design variables, the volume of the gearbox is determined as the objective function, and the critical condition and transmission ratio are determined as constraint conditions. The volume of the wind turbine gearbox under different transmission schemes is optimized. In a specific embodiment, a three-stage planetary gear train transmission scheme (hereinafter referred to as 3P transmission scheme) is taken as an example, the gears are all straight tooth involute gears, the gear material is 18CrNiMo7-6, and the tooth width is the same. The configuration of the three-stage planetary gear train transmission system is shown in Figure 1 It should be understood by those skilled in the art that the transmission schemes of two-stage planetary gear train and two-stage planetary gear train plus one-stage parallel shaft train are similar to the three-stage planetary gear train.

[0021] The process of optimizing the volume of the wind turbine gearbox is as follows: 1. Determine the maximum gear load strength factor For high-power wind turbine gearbox transmission system, the sun gear is the most serious part of fatigue pitting, so the maximum tooth load strength factor is determined according to the tooth surface contact fatigue strength formula of the sun gear and the planet gear, and the calculation process is as follows: In the above formula, is the ratio of the number of teeth of the planet gear to the sun gear, is the transmission ratio of the planet gear system, is the number of teeth of the planet gear, is the number of teeth of the sun gear; is the nominal Hertz contact stress, is the node area coefficient, is the elastic coefficient, is the degree of coincidence coefficient, is the helix angle coefficient, is the circumferential force of the sun gear of the planet gear system, is the diameter of the sun gear, is the tooth width of the planet gear system; is the actual contact stress, is the use coefficient, is the dynamic load coefficient, is the tooth load distribution coefficient for tooth surface contact fatigue strength calculation, is the intertooth load distribution coefficient for tooth surface contact fatigue strength calculation; is the contact fatigue limit of the test gear, preferably 1500Mpa, is the minimum safety factor of the contact strength, preferably 1.25. is the life coefficient for tooth surface contact fatigue strength calculation, is the lubricant coefficient, is the speed coefficient, is the roughness coefficient, is the work hardening coefficient, is the size coefficient for tooth surface contact fatigue strength calculation.

[0022] 2. According to the maximum tooth load strength factor, the volume of the sun gear, the volume of the planet gear and the volume of the inner gear ring are calculated, and the volume of the wind turbine gearbox is determined according to the volume of the sun gear, the volume of the planet gear and the volume of the inner gear ring According to formula (5), the volume of the sun gear , the volume of the planet gear , and the volume of the inner gear ring are respectively: In the above formula, is the input torque of the planet carrier, is the ratio of the number of teeth of the planet gear to the number of teeth of the sun gear, which is obtained by formula (1); is the number of planet gears, is the maximum tooth load strength factor, is the meshing uniform load coefficient, which can refer to Table 1 below, is the transmission efficiency factor under different transmission ratios, is the gear volume correction factor under different planetary gear trains.

[0023] Table 1 Meshing uniform load coefficient of wind power planetary gear transmission device According to formulas (6)-(8), the volume of the wind power gear box under the 3P transmission scheme is: In the above formula, is the proportion factor according to the proportion of the gear in the weight of the gear box.

[0024] 3. Setting boundary constraint conditions for optimizing the volume of the wind power gear box In the case where the design variables are the transmission ratio distribution and the planet gear number distribution of the three-stage planetary gear train, the constraint conditions of the wind power gear transmission are as follows: In the above formula, , are the lower limit and the upper limit of the transmission ratio distribution of each stage of the three-stage planetary gear train, respectively, are the upper limit and the lower limit of the number of planet gears of each stage of the three-stage planetary gear train, wherein the limit transmission ratios are shown in Table 2 below: Table 2 Limit transmission ratio requirements under different numbers of planet gears is the number of teeth of the sun gear. 4. Using the genetic algorithm with the introduction of the simulated annealing mechanism to optimize the volume of the wind power gear box as the objective function according to the boundary constraint conditions for optimizing the volume of the wind power gear box

[0025] Considering that the genetic algorithm is prone to fall into a local optimal solution, in this embodiment, the simulated annealing mechanism is introduced into the genetic algorithm, and the specific process is as follows: Figure 2 ​As shown, this method solves combinatorial and nonlinear optimization problems by simulating the physical process of metal being heated to a high temperature and then gradually cooled. It utilizes the characteristics of simulated annealing random search and probabilistic acceptance of the worst solution to randomly perturb the current state of the mutated offspring individuals, generating new solutions. The Metropolis criterion determines whether to accept the new solution, thus escaping the local optima that may be encountered by the genetic algorithm. This increases the diversity of the overall hybrid optimization algorithm's search and also accelerates its convergence speed.

[0026] In this embodiment, the basic algorithm model of the genetic algorithm that incorporates simulated annealing is as follows: In the above formula, The design variables are encoded using binary encoding. To establish the initial sample size for the population, a preferred value of 300 was selected. The fitness value of the objective function for the volume of the wind turbine gearbox is calculated. The set number of population evolution iterations is 600-1000, with the optimal value being 600-1000. These are the selection, crossover, and mutation operators in the genetic algorithm. This is the name of the variable function that simulates the annealing mechanism.

[0027] Through optimization in this step, the theoretical minimum volume of the wind turbine gearbox can be obtained.

[0028] S2. Optimize the transmission ratio and the number of planetary gears based on the theoretical minimum volume of the wind turbine gearbox. Under the same speed ratio and torque requirements, the more planetary gears in the first stage, the lighter the wind turbine gearbox can theoretically be designed. Figure 3 As shown.

[0029] For the second-stage planetary gear train, the volume of the wind turbine gearbox first decreases and then increases with the increase in the number of planetary gears. Its relative volume is minimized when the number of second-stage planetary gears is 6. Figure 4 As shown.

[0030] For the third-stage planetary gear train, the overall volume of the wind turbine gearbox decreases slightly when the number of planetary gears increases. However, once the number of third-stage planetary gears exceeds the critical value under different allocation schemes, the allocation of the number of planetary gears will fail to meet the basic requirements such as critical conditions and transmission ratio conditions, as shown in Table 3. Table 3. Influence of the number of third-stage planetary gears on the volume of wind turbine gearboxes. In summary, in combination with the number of planetary gears of each planetary gear train and the distribution of transmission ratio, the influence law and calculation results of the volume of the three-stage planetary transmission wind turbine gearbox, the number of planetary gears and the transmission ratio of each stage train when the volume of the wind turbine gearbox is the smallest are shown in Table 4 below: Table 4 Optimal design values of the speed ratio and the number of planetary gears of each stage of the wind turbine gearbox S3, geometric design of the gear According to the parameters such as rated power, rated torque, total transmission ratio, in combination with the three-stage planetary transmission configuration scheme, the preliminary transmission ratio and the distribution of the number of planetary gears, the detailed design of the gear macroscopic parameters is performed first to determine the basic design parameters of each gear pair, then the parameters of each transmission shaft are calculated and the selection design of the bearing is carried out to obtain the structure parameters and layout of the detailed three-stage planetary gear system. The specific process is as follows: 1. Determining the basic parameters and objective function of the gear geometric size of the planetary gear train The traditional gear experience design is generally to calculate according to the bending fatigue strength first, and then to check by the contact fatigue strength, the shortcoming of which is that the determination of the design variable parameters is often limited to the design manual and the experience design range, resulting in design redundancy caused by too large safety factor, and the collaborative optimization of volume, cost and safety and reliability cannot be realized.

[0031] In this embodiment, based on the equal strength lightweight design concept, in combination with the strength safety requirement, the basic parameters of the gear geometric size are preliminarily determined , including the normal modulus of each planetary gear train , the number of inner tooth ring teeth , the number of planetary gear teeth , the number of sun gear teeth , the inner tooth ring tooth width , the planetary gear tooth width , the sun gear tooth width , the pressure angle , the spiral angle , the inner tooth ring modification coefficient , the planetary gear modification coefficient , the sun gear modification coefficient , as shown in equation (17), In order to realize the lightweight and high power of the gear transmission system under the premise of ensuring the reliability of the gear transmission system, the total volume of each planetary gear train of the gear transmission system, the difference of the contact fatigue safety factor of each planetary gear train, and the difference of the bending fatigue safety factor of each planetary gear train are selected as the objective function of the gear geometric size, as shown in equations (16)-(18).

[0032] In the above formula, , is the inner ring volume proportion factor, is the contact fatigue safety factor of the inner ring, the planet wheel and the sun wheel, is the bending fatigue safety factor of the inner ring, the planet wheel and the sun wheel.

[0033] 2, set the constraint condition of planetary gear transmission The planetary gear transmission constraint is a basic requirement to ensure reasonable and reliable gear design. In the prior art, when carrying out the forward design of detailed gear parameters, the setting of the constraint condition is not comprehensive enough, resulting in too many debugging times of design checking and large design time cost.

[0034] In order to improve the above shortcomings, in the embodiment, a series of conditions including the upper and lower boundary condition constraints of the basic parameters of the gear geometric size, the design condition constraints of the planetary gear teeth, the planetary carrier structure constraints and the strength constraints are comprehensively considered.

[0035] 2-1, set the boundary constraint of the basic parameters of the gear geometric size The boundary constraint of the basic parameters of the gear geometric size is shown in the following formula (19): In the above formula, , the underlined and overlined respectively represent the lower boundary and the upper boundary of the gear basic parameters.

[0036] 2-2, set the concentric condition constraint of planetary gear transmission For planetary gear transmission, the concentric condition constraint is to ensure that the actual center distance of the inner and outer meshing pairs of the gear under the planetary gear train is kept equal. The concentric constraint condition is shown in formula (20): In the above formula, , represents the actual center distance of the outer meshing pair of the gear under the planetary gear train, represents the actual center distance of the inner meshing pair of the gear under the planetary gear train.

[0037] 2-3, set the abutment condition constraint of planetary gear transmission In order to avoid interference and collision between adjacent planetary gears in the process of planetary gear transmission, a certain gap is set on the corresponding line of the planetary gear tooth top circle in the embodiment, which is generally 0.5 times the gear modulus, that is, the abutment condition constraint is shown in formulas (21) and (22): In the above formula, , Rptis the dedendum radius of the planet gears in each planetary gear train, Dptis the dedendum diameter of the planet gears in each planetary gear train, Dcisthe distance between the centers of two adjacent planet gears in each planetary gear train, Nptis the number of planet gears.

[0038] 2-4, setting the assembly constraints of each planetary gear train In this embodiment, the number of each planetary gear in the initial wind turbine gearbox is greater than 1, so the assembly constraints of each planetary gear train should also be set to evenly distribute the multiple planet gears around the central gear, and the assembly constraint condition is shown in equation (23): In the above equation, , Nstis the number of teeth of the sun gear, Nringis the number of teeth of the ring gear, Nptis the number of planet gears, and is an integer.

[0039] 2-5, setting the constraint conditions of the meshing angles of the inner and outer meshing pairs in each planetary gear train Considering that the changes in the center distance and the pressure angle affect the change in the meshing angle during the meshing of the gear pairs in the planetary gear train, and the size of the meshing angle also causes differences in the contact area and the contact length of the gear tooth surface and the strength of the bearing capacity, the reasonable boundary range of the meshing angle needs to be given to ensure its applicability when designing the basic parameters of the gear, and the constraint condition is shown in equation (24): In the above equation, , is the meshing angle of the outer meshing pair of each planetary gear train, is the meshing angle of the inner meshing pair of each planetary gear train.

[0040] 2-6, setting the constraint conditions of the face contact ratio of the inner and outer meshing pairs of the planetary gear train A face contact ratio greater than 1 is a necessary condition for the normal continuous transmission of each gear in the planetary gear train, and a higher face contact ratio indicates that the number of gear pairs participating in the meshing of the gear is greater, the fluctuation change in the time-varying meshing stiffness curve of the gear is smaller, the impact of the meshing in and out is reduced, and the smoothness and life of the gear transmission are also increased. In view of the special working condition environment of low-speed heavy load of the wind turbine, a larger face contact ratio should be required as much as possible, while considering that a too narrow design boundary will lead to the result being unable to converge, in this embodiment, the constraint condition of the face contact ratio of the inner and outer meshing pairs of the planetary gear train is set, as shown in equation (25): In the above equation, , is the end face coincidence degree of the inner and outer meshing pairs of the planetary gear train.

[0041] 2-7, constraint condition of setting the tooth width coefficient The size of the tooth width coefficient is proportional to the carrying capacity of each gear in the planetary gear stage, but the uneven distribution of the tooth load caused by the too large tooth width coefficient will lead to the excessive concentration of the local stress of the gear, bearing and other components. Therefore, in the present embodiment, the tooth width coefficient is included in the boundary constraint of the gear system parameter design, the influence of the bearing support configuration mode and the working tooth surface hardness on the tooth width coefficient is considered, and the constraint condition of the tooth width coefficient is shown in the following formulas (26) and (27): In the above formula, , is the tooth width coefficient, is the tooth width of the inner gear ring of each planetary gear train, is the diameter of the division circle of the inner gear ring of each planetary gear train.

[0042] 2-8, constraint condition of setting the gear contact fatigue strength safety factor and the bending fatigue strength safety factor of the planetary gear train In order to ensure that the gear box of the large-power wind turbine generator can run to the preset service life for a long time under the complex and variable heavy load working condition environment, the constraint condition of setting the gear contact fatigue strength safety factor and the bending fatigue strength safety factor of the planetary gear train is shown in formula (28) In the above formula, , is the minimum contact fatigue strength safety factor of the gear in each gear train, generally taken as 1.25, is the minimum bending fatigue strength safety factor of the gear in each gear train, generally taken as 1.56.

[0043] 2-9, constraint condition of preventing interference of the tooth root transition curve of the sun gear and the planetary gear outer meshing pair, constraint condition of preventing interference of the tooth root transition curve of the inner gear ring and the planetary gear, constraint condition of preventing overlapping interference of the tooth profile, and constraint condition of limiting the displacement coefficient In order to avoid a series of problems such as the failure of the normal and stable operation of the gear pair, the excessive impact load on the gear caused by the meshing interference of each gear in the planetary gear train, the constraint condition of preventing the interference of the tooth root transition curve of the sun gear and the planetary gear outer meshing pair (corresponding to formulas 29 and 30), the constraint condition of preventing the interference of the tooth root transition curve of the inner gear ring and the planetary gear (corresponding to formulas 31 and 32), the constraint condition of preventing the overlapping interference of the tooth profile (corresponding to formulas 33 and 34), and the constraint condition of limiting the displacement coefficient (corresponding to formulas 29, 30 and 31) are set in the present embodiment; formulas (29)-(35) are as follows: In the above formula, , is the normal addendum coefficient of each gear of each planetary gear train; is the sun gear modification coefficient, is the planetary gear modification coefficient, is the inner ring gear modification coefficient; is the number of teeth of the sun gear, is the number of teeth of the planetary gear, is the number of teeth of the inner ring gear; are the sun gear addendum circle pressure angle, the planetary gear addendum circle pressure angle and the inner ring gear addendum circle pressure angle in each planetary gear train, respectively; is the meshing angle of the outer meshing pair of each planetary gear train, is the meshing angle of the inner meshing pair of each planetary gear train; is the actual meshing center distance corresponding to each planetary gear train, are the number of teeth of the inner ring gear gear shaping cutter, the addendum circle pressure angle and the meshing angle when the inner gear is shaped, respectively; is the geometric angle (planetary gear perspective) calculated by formula (33), which represents the relative position relationship between the planetary gear addendum circle and the inner ring gear dedendum circle, and the unit is rad; is the geometric angle (inner ring gear perspective) calculated by formula (34), which represents the relative position relationship between the inner ring gear addendum circle and the planetary gear dedendum circle, and the unit is rad.

[0044] 2-10, set the addendum thickness constraint condition of the center wheel and the planetary gear The angular modification gear in the planetary gear train is easy to cause insufficient gear addendum strength due to its own excessive modification coefficient, so in the embodiment, the addendum thickness of the center wheel and the planetary gear in the surface hardened wind power gear box is taken as more than 0.4 times the modulus, and the constraint condition is shown in formula (36): In the above formula, , are the addendum circle diameters of the sun gear, the planetary gear and the inner ring gear of each planetary gear train, respectively; is the sun gear modification coefficient, is the planetary gear modification coefficient, is the inner ring gear modification coefficient; are the sun gear addendum circle pressure angle, the planetary gear addendum circle pressure angle and the inner ring gear addendum circle pressure angle in each planetary gear train, respectively; Dti is the tip circle diameter of the ith stage sun gear, Dpi is the tip circle diameter of the ith stage planet gear, Dni is the tip circle diameter of the ith stage ring gear, is the pressure angle at the pitch circle, is the involute function.

[0045] 2-11, Set the planet carrier deformation constraint condition In the process of gear transmission of the composite planetary gear train of the wind turbine gearbox, if the torsional deformation angle of the double-sided plate cage type planet carrier exceeds the reasonable range, it will lead to the occurrence of meshing deviation in the meshing of the inner and outer meshing gear pairs, and serious load deviation will be caused. In this embodiment, the torsional stiffness of the double-sided plate cage type planet carrier is ensured to meet the requirements from the aspects of lightweight design of structural size, the number of planet gears, the tip circle diameter of the planet gears and the outer diameter size of the ring gear will all affect the available space of the connecting column of the double-sided plate cage type planet carrier, thereby changing the deformation amount of the double-sided plate cage type planet carrier. Therefore, the basic size structure of the simplified double-sided plate cage type planet carrier is determined through the number of planet gears and the diameter size of each gear, the corresponding torsional deformation amount of the planet pin shaft is calculated according to the theory of material mechanics, and the corresponding constraint conditions are given as shown in the following formulas (37)-(39), In the above formula, , is the torsional angle of the double-sided plate cage type planet carrier under the second and third stage planetary gear train, is the effective tooth width of the planet gear under the second and third stage planetary gear train, is the shear modulus of the material; is the moment of inertia of the double-sided plate cage type planet carrier under the second and third stage planetary gear train, is the input torque of the second and third stage planetary gear train; is the relative torsional angle of the double-sided plate cage type planet carrier under the rated operating condition of the second and third stage planetary gear train, is the relative torsional deformation amount of the pin shaft of the double-sided plate cage type planet carrier under the rated operating condition of the second and third stage planetary gear train, is the maximum allowable torsional angle requirement of the double-sided plate cage type planet carrier.

[0046] In some embodiments, considering that a relatively narrow transmission ratio interval may lead to divergence or local optimization of the optimization design result, the transmission ratio of each stage planetary gear train is preliminarily determined and is floated up and down by 5%, as shown in formula (40), so as to expand the design space and increase the diversity of solutions, and obtain the optimal parameter design value of the wind turbine gearbox transmission system: In the above formula, , is the initial design value of the transmission ratio of each stage of planetary gear train, is the final design value of the transmission ratio of each stage of planetary gear train.

[0047] 3. According to the basic parameters of the gear geometry of the planetary gear train and the target function, and in combination with the constraint conditions of the planetary gear train transmission, the gear geometry is optimized using the improved multi-objective optimization genetic algorithm The improved multi-objective optimization genetic algorithm provided in the present embodiment adopts a real number coding method for a large number of design parameter variables to reduce the omission of data samples, introduces an elite reservation strategy to accelerate the convergence speed, borrows an external point penalty function to establish a constraint violation penalty mechanism for the population individuals, and then carries out adaptive non-dominated sorting according to the deb individual comparison criterion to better balance the constraint violation degree and the target function, and has good effects on solving this type of constrained multi-objective nonlinear optimization problem. The flow steps of the algorithm include: Step 1: Generate standardized Latin hypercube sampling sample data according to the sample range specified by the constraint condition, and establish an initialized population .

[0048] Step 2: In the adaptive non-dominated sorting, the external point penalty function penalty rule and the deb individual comparison criterion are introduced, the feasibility of the population sample individual solution is judged and the corresponding constraint violation degree is calculated through the external point penalty function formulas (41)-(43), and on this basis, the non-dominated solution set of different levels is sorted and established based on the deb individual comparison criterion, and the basic principle is to divide and judge the dominance relationship between individual solution sets according to the size of the target function of the feasible solution set, the feasibility of the solution set, and the size of the constraint violation degree of the infeasible solution set in descending order of priority.

[0049] In the above formula, is the constraint violation degree of the population sample individual, is the penalty factor Step 3: Calculate the crowding degree of the individual of the corresponding level according to the target function of each level of non-dominated solution set As shown in formula (44), the larger the individual crowding degree, the more conducive to the distribution of population diversity, and naturally the solution set in the corresponding Pareto layer is better.

[0050] In the above formula, are the target values corresponding to the th individual, the th individual and all individuals on the th objective function, respectively.

[0051] Step four: the initial population is selected by tournament selection to produce a parent population suitable for breeding, since the design parameter coding method is real number coding, the parent population is generated by simulated binary crossover and mutation to produce a child population and the child population is combined to produce a new population .

[0052] Step five: the new population produced by combination is evaluated Steps two and three are repeated, that is, self-adaptive non-dominated sorting and calculation of crowding factor are carried out.

[0053] Step six: the sorted new population is evaluated The first N priority individuals are selected according to the elite preservation strategy to form the next generation of new population .

[0054] Step seven: the population evolution generation number is set, when the set value is reached, the optimization process is terminated, otherwise, step four is entered for the next iteration of optimization.

[0055] Based on the above optimization, the three-stage planetary wind turbine gearbox system parameter optimization design results are as follows in Table 5: Table 5 Detailed gear parameter design results The super-compact wind turbine gearbox transmission system configuration design method optimizes the gear box volume, transmission ratio and other parameters, gives the gear box transmission system geometric design parameters, realizes significant reduction of gear box volume and weight under the premise of ensuring bearing capacity and reliability, reduces transportation and installation cost, improves power density and operation stability, and is especially suitable for offshore and large-scale onshore wind turbines with limited space and high maintenance cost.

[0056] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A method of designing a configuration of an ultra-compact wind power gearbox drive system, characterized by, The method comprises the following steps: optimizing the volume of the wind turbine gearbox to obtain a theoretical minimum value of the volume; determining the number of planetary gears and the transmission ratio of each stage of the planetary gear train when the volume of the wind turbine gearbox is minimized according to the theoretical minimum value of the volume of the wind turbine gearbox; geometrically designing the gears to obtain a design result of the gear parameters, including: determining basic parameters and a target function of the geometric dimensions of the gears of the planetary gear train, setting a constraint condition of the gear transmission of the planetary gear train, and optimizing the geometric dimensions of the gears by using an improved multi-objective optimization genetic algorithm according to the basic parameters and the target function of the geometric dimensions of the gears of the planetary gear train in combination with the constraint condition of the gear transmission of the planetary gear train.

2. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, The method for optimizing the volume of the wind turbine gearbox to obtain a theoretical minimum value of the volume comprises the following steps: determining a maximum tooth load strength factor; calculating the volume of the sun gear, the volume of the planetary gears, and the volume of the inner ring gear according to the maximum tooth load strength factor; determining the volume of the wind turbine gearbox according to the volume of the sun gear, the volume of the planetary gears, and the volume of the inner ring gear; setting a boundary constraint condition for the optimization of the volume of the wind turbine gearbox; optimizing the volume of the wind turbine gearbox by using a genetic algorithm with a simulated annealing mechanism according to the boundary constraint condition for the optimization of the volume of the wind turbine gearbox, taking the volume of the wind turbine gearbox as a target function, to obtain the theoretical minimum value of the volume.

3. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 2, wherein, The maximum tooth load strength factor is determined according to a tooth surface contact fatigue strength formula of the sun gear and the planetary gears.

4. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 2, wherein, The boundary constraint condition for the optimization of the volume of the wind turbine gearbox includes lower and upper limits of the transmission ratio distribution of each stage of the three-stage planetary gear train, and also includes upper and lower limits of the number of planetary gears of each stage of the three-stage planetary gear train.

5. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, The method for optimizing the transmission ratio and the number of planetary gears according to the theoretical minimum value of the volume of the wind turbine gearbox comprises the following steps: under the same speed ratio and torque requirements, the more the number of the first-stage planetary gears is, the lighter the weight of the wind turbine gearbox is; 6. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, when the number of the second-stage planetary gears is 6, the relative volume of the wind turbine gearbox is the smallest.

7. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, The basic parameters of the geometric dimensions of the gears include the number of teeth, the modulus, the pressure angle, the helix angle, the tooth width, and the modification coefficient.

8. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, The target function of the geometric dimensions of the gears includes the total sum of the gear volumes of each stage of the planetary gear train, the difference of the contact fatigue safety factors of each stage of the planetary gear train, and the difference of the bending fatigue safety factors of each stage of the planetary gear train. The constraint condition of the gear transmission of the planetary gear train includes the following steps: setting a boundary constraint of the basic parameters of the geometric dimensions of the gears; setting a concentric constraint of the planetary gear transmission; setting an abutment constraint of the planetary gear transmission; setting an assembly constraint of each stage of the planetary gear train; setting a constraint condition of the meshing angle of the inner and outer meshing pairs of each stage of the planetary gear train; setting a constraint condition of the end face coincidence degree of the inner and outer meshing pairs of the planetary gear train; setting a constraint condition of the tooth width coefficient; setting a constraint condition of the contact fatigue strength safety factor and the bending fatigue strength safety factor of the planetary gear train; setting a constraint condition of the tooth root transition curve interference prevention of the sun gear and the outer meshing pair of the planetary gears, a constraint condition of the tooth root transition curve interference prevention of the inner ring gear and the planetary gears, a constraint condition of the tooth profile overlap interference prevention, and a constraint condition of the modification coefficient limitation; setting a constraint condition of the addendum thickness of the center gear and the planetary gears; setting a constraint condition of the deformation of the planet carrier.

9. The method of designing an ultra-compact wind power gearbox transmission system configuration according to claim 1, wherein, The improved multi-objective optimization genetic algorithm comprises the following steps: According to the sample range specified by the constraint condition, generate standardized Latin hypercube sampling sample data, and establish an initialized population; In the adaptive non-dominated sorting, the feasibility of the population sample individual solution is judged by an external point penalty function, and the corresponding constraint violation degree is calculated, the deb individual comparison criterion is sorted based on, and a non-dominated solution set of different levels is established; According to the objective function of each level of the non-dominated solution set, the crowding degree of the individual of the corresponding level is calculated; Through tournament selection, a parent population suitable for breeding is generated from the initial population, the parent population is generated through simulated binary crossover and mutation to generate a child population, and the child population is combined to generate a new population; The adaptive non-dominated sorting and the calculation of the crowding degree are carried out for the new population generated by the combination; According to the elite retention strategy, the first N priority individuals are selected from the sorted new population to form a new population of the next generation; The population evolution generation number is set, and when the set value is reached, the optimization process is terminated, otherwise the next iteration of optimization is continued.

10. An ultra-compact wind power gearbox drive system, characterized in that, The configuration design method is designed by any one of claims 1-9.

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