A fast optimization method for the wire diameter and number of parallel windings of high-speed motor stator windings

Abstract

The invention discloses a fast optimization method for the wire diameter and the number of parallel windings of a high-speed motor stator winding, including: finite element modeling, stratifying the stator slots radially, and using the finite element method to calculate the magnetic flux density data of each layer; inputting the basic parameters of the motor and the magnetic flux density curve in the slot; setting the optimization interval and step size of the wire diameter and the number of parallel windings; obtaining the slot filling rate in the optimization interval; calculating the DC loss, eddy current loss and AC loss of the stator winding; taking the scheme with the minimum AC loss of the stator winding as the initial optimization scheme; on the basis of the initial optimization scheme, selecting similar wire gauges and the number of parallel windings to generate candidate schemes with slot filling rates that meet the requirements; using the finite element method to calculate the DC loss, eddy current loss and AC loss of the stator winding; using the thermal network method to calculate the stator and rotor temperature rise; selecting the scheme with the lowest winding AC loss and stator and rotor temperature rise as the combination scheme of the winding wire diameter and the number of parallel windings. The invention has a short optimization design cycle, and the result is close to the theoretical optimum, which greatly improves the optimization speed.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-high speed motor design, and particularly relates to a rapid optimization design method for the wire diameter and the number of parallel windings of a high-speed motor stator winding. Background Art

[0002] Fuel Cell Compressor (FCC) is the most important component in the fuel cell system. It mostly uses ultra-high speed permanent magnet motor as the driving unit. The high speed of the motor can effectively improve the power density and volume density of the air compressor. It can also provide higher pressure and larger flow at the same time with the centrifugal compressor pump head, which can greatly improve the power density and efficiency of the fuel cell system, greatly reduce the size and cost of the fuel cell system, and improve the water balance. However, the eddy current loss of the winding of the high-speed permanent magnet motor during ultra-high speed operation is much greater than that of the conventional motor, resulting in increased eddy current loss of the motor winding, reduced efficiency, and serious heating of the motor. In order to reduce the eddy current loss of the winding caused by the skin effect and proximity effect of the conductor, the stator winding of the high-speed permanent magnet motor is mostly used with a smaller copper wire diameter and a larger number of parallel windings. How to choose the best wire diameter and number of parallel windings is an important issue that cannot be ignored in the design of ultra-high-speed motors.

[0003] Currently, the commonly used stator winding and parallel winding number design methods in high-speed motor design in the industry include empirical formula method and finite element scanning method.

[0004] The design steps of the empirical formula method are as follows:

[0005] S1: In order to make the bare copper wire diameter of the enameled wire smaller than the penetration depth of the skin effect in the conductor, the maximum wire diameter requirement is calculated using formula (1) [1-2];

[0006]

[0007] Among them, r is the bare copper wire radius of the conductor; ω is the current frequency in the conductor; μ is the magnetic permeability of the conductor; σ is the electrical conductivity of the conductor;

[0008] S2: Check the wire gauge standard and select 2 to 4 commonly used wire diameter specifications according to the maximum wire diameter requirements;

[0009] S3: Using the slot fill rate calculation formula (2), with a certain slot fill rate as the upper limit (80% for general motors), select the maximum number of parallel windings for the 2 to 4 commonly used wire diameter specifications, and obtain matching solutions for the 2 to 4 wire diameters and the number of parallel windings;

[0010]

[0011] Among them, α is the stator slot filling rate, d wireA is the outer diameter of the enameled wire, n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot;

[0012] S4: Comprehensively consider the motor electrical density, slot fill rate, winding processability and cost, and select the appropriate wire diameter and parallel winding number matching solution.

[0013] The above empirical formula method directly ignores the eddy current loss of the stator winding caused by the skin effect and the proximity effect, and is widely used in the design process of low-speed motors. However, the eddy current loss of the stator winding of high-speed motors cannot be ignored, so it is not suitable for the design process of high-speed motors.

[0014] The design steps of the finite element scanning method are as follows:

[0015] Step 1: Finite element modeling, and setting the optimization interval and optimization step length for the number of windings and wire diameter;

[0016] Step 2: Use the slot fill rate formula to find candidate solutions that meet the slot fill rate requirements within the optimization interval;

[0017] Step 3: Use the finite element method to scan and calculate the stator winding DC loss, eddy current loss and AC loss of each candidate solution one by one;

[0018] Step 4: Use the thermal network method to scan and calculate the stator and rotor temperature rise of each candidate solution one by one;

[0019] Step 5: Consider the appropriate wire gauge, stator winding AC loss and stator and rotor temperature rise, and select the appropriate stator winding wire diameter and number of parallel windings.

[0020] The calculation results of the above-mentioned finite element scanning method are relatively accurate, but it requires huge computing resources and optimization design time, which greatly prolongs the development cycle of the motor and has a slow optimization speed.

[0021] Therefore, in the current high-speed motor design, it is urgent to develop a fast and effective method to optimize the stator winding wire diameter and the number of parallel windings. Summary of the invention

[0022] In view of the problems existing in the prior art, the present invention provides a rapid optimization method for the wire diameter and the number of parallel windings of a high-speed motor stator winding. After using the rapid optimization method, the optimization calculation cycle is short, which can greatly reduce the design cycle of the product: the finite element scanning method requires a large amount of computing resources and takes at least 5 to 8 days to obtain the optimal solution, while the rapid optimization design method can obtain the optimal solution within 5 to 8 hours, shortening the design cycle by more than 20 times; it is more suitable for the optimization design application of high-speed motors: compared with the empirical formula method, the optimal solution obtained by this method has better performance in terms of motor efficiency, motor temperature rise, wire package size, stator winding component weight and reliability; the optimization result is close to the theoretical optimum, and the optimization accuracy meets the engineering requirements: considering factors such as motor efficiency and motor temperature rise, the preliminary optimization solution can obtain motor performance that is almost the same as the theoretical optimal solution, and the performance difference between them can be ignored. On the basis of the preliminary optimization solution, the finite element method is used for further local optimization, and a winding solution that is exactly the same as the theoretical optimum can be obtained; the loss model of the optimization algorithm is simple, which is convenient for modifying other motor parameters to optimize and reduce the AC loss of the stator winding.

[0023] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0024] A method for rapidly optimizing the wire diameter and the number of parallel windings of a high-speed motor stator winding is provided, the method comprising the following steps:

[0025] Step 1: Finite element modeling, divide the stator slots into 10 to 20 layers in the radial direction, and use the finite element method to calculate the magnetic flux density data of each layer in the stator slots;

[0026] Step 2: Input the basic parameters of the motor and the magnetic flux density curve in the slot into the calculation program;

[0027] Step 3: Set the optimization interval and step size of wire diameter and number of parallel windings;

[0028] Step 4: Calculate the slot fullness rate in the optimization interval;

[0029] Step 5: Calculate the stator winding DC loss, eddy current loss and AC loss of the above solution;

[0030] Step 6: Take the solution with the smallest AC loss of the stator winding as the initial optimization solution;

[0031] Step 7: Based on the initial optimization scheme, select 2 to 4 groups of similar wire gauges and 2 to 4 groups of similar numbers of parallel windings to generate candidate schemes that meet the slot filling rate requirements;

[0032] Step 8: Use the finite element method to calculate the stator winding DC loss, eddy current loss and AC loss of the above scheme respectively;

[0033] Stpe9: Calculate the stator and rotor temperature rise of the above scheme using the thermal network method;

[0034] Step 10: Select the solution with the lowest stator winding AC loss and stator and rotor temperature rise as the combination of stator winding wire diameter and number of parallel windings.

[0035] In order to solve the technical problem, the further technical solution adopted by the present invention is:

[0036] Furthermore, in Step 4, the calculation formula for the slot fill rate is as follows:

[0037]

[0038] Among them, α is the stator slot filling rate; d wire A is the outer diameter of the enameled wire; n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot.

[0039] Furthermore, in Step 5, the calculation formulas for stator winding DC loss, eddy current loss, and AC loss are as follows:

[0040] P ac =P dc +P eddy ;

[0041]

[0042]

[0043]

[0044]

[0045]

[0046] Among them, P dc is the stator winding DC loss, P eddy is the stator winding eddy current loss, P ac is the AC loss of the stator winding, N is the number of conductors per slot, a is the number of stator windings, l is the effective length of the conductor in the slot, l turn is the conductor full turn length, ρ is the conductor resistivity, h is the slot equivalent height, p is the number of motor poles, N rpm is the motor speed, ω is the angular frequency of the current in the conductor, d is the conductor diameter, B i is the magnetic field density of the i-th layer in the slot, n is the number of conductor distribution layers, d gap is the gap between conductors in the slot, R dc is the DC phase resistance of the stator winding, I rmsis the effective value of the stator winding phase current, b is the number of parallel branches, d is wire is the outer diameter of the enameled wire.

[0047] Furthermore, in Step 3, the optimal interval and step size of the wire diameter are set to 0.3-1.5 mm and 0.01-0.1 mm, respectively, and the optimal interval and step size of the number of windings are set to 1-50 and 1, respectively.

[0048] The beneficial effects of the present invention are:

[0049] 1. The optimization calculation cycle of the present invention is short, which can greatly reduce the design cycle of the product: the finite element scanning method requires a large amount of computing resources and takes at least 5 to 8 days to obtain the optimal solution, while the rapid optimization design method can obtain the optimal solution within 5 to 8 hours, shortening the design cycle by more than 20 times, greatly improving the optimization speed;

[0050] 2. The present invention is more suitable for the optimization design application of high-speed motors: compared with the empirical formula method, the optimal solution obtained by this method has better performance in terms of motor efficiency, motor temperature rise, coil size, stator winding assembly weight and reliability;

[0051] 3. The optimization result of the present invention is close to the theoretical optimum, and the optimization accuracy meets the engineering requirements: considering factors such as motor efficiency and motor temperature rise, the preliminary optimization scheme can obtain motor performance that is almost the same as the theoretical optimum scheme, and the performance difference between them can be ignored. On the basis of the preliminary optimization scheme, the finite element method is used for further local optimization, and a winding scheme that is exactly the same as the theoretical optimum can be obtained;

[0052] 4. The loss model of the optimization algorithm of the present invention is simple, and it is convenient to modify other parameters of the motor to optimize and reduce the AC loss of the stator winding.

[0053] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of a method for rapidly optimizing the wire diameter and the number of parallel windings of a high-speed motor stator winding according to the present invention;

[0055] Figure 2 Schematic diagram of slot filling rate for different wire diameters and parallel winding numbers in an embodiment of the present invention;

[0056] Figure 3 Schematic diagram of eddy current loss of windings with different wire diameters and numbers of parallel windings in an embodiment of the present invention;

[0057] Figure 4 Schematic diagram of DC loss of windings with different wire diameters and numbers of parallel windings in an embodiment of the present invention;

[0058] Figure 5 Schematic diagram of AC loss of windings with different wire diameters and numbers of parallel windings in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following is a specific embodiment of the present invention, and those skilled in the art can easily understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented in other different ways, that is, different modifications and changes can be made without departing from the scope disclosed by the present invention.

[0060] Embodiment 1:

[0061] A fast optimization method for the wire diameter and number of parallel windings of high-speed motor stator windings, such as Figure 1 As shown, the fast optimization method includes the following steps:

[0062] Step 1: Finite element modeling, divide the stator slots into 10 to 20 layers in the radial direction, and use the finite element method to calculate the magnetic flux density data of each layer in the stator slots;

[0063] Step 2: Input the basic parameters of the motor and the magnetic flux density curve in the slot into the calculation program;

[0064] Step 3: Set the optimal range and step size of the wire diameter and the number of parallel windings. The optimal range and step size of the wire diameter are set to 0.3-1.5 mm and 0.01-0.1 mm respectively, and the optimal range and step size of the number of parallel windings are set to 1-50 and 1 respectively.

[0065] Step 4: Calculate the slot full rate in the optimization interval. The calculation formula of the slot full rate is as follows:

[0066]

[0067] Among them, α is the stator slot filling rate; d wire A is the outer diameter of the enameled wire; n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot;

[0068] Step 5: Calculate the DC loss, eddy current loss and AC loss of the stator winding of the above scheme. The calculation formulas for the DC loss, eddy current loss and AC loss of the stator winding are as follows:

[0069] P ac =P dc +P eddy ;

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] Among them, P dc is the stator winding DC loss, P eddy is the stator winding eddy current loss, P ac is the AC loss of the stator winding, N is the number of conductors per slot, a is the number of stator windings, l is the effective length of the conductor in the slot, l turn is the conductor full turn length, ρ is the conductor resistivity, h is the slot equivalent height, p is the number of motor poles, N rpm is the motor speed, ω is the angular frequency of the current in the conductor, d is the conductor diameter, B i is the magnetic field density of the i-th layer in the slot, n is the number of conductor distribution layers, d gap is the gap between conductors in the slot, R dc is the DC phase resistance of the stator winding, I rms is the effective value of the stator winding phase current, b is the number of parallel branches, d is wire is the outer diameter of the enameled wire;

[0076] Step 6: Take the solution with the smallest AC loss of the stator winding as the initial optimization solution;

[0077] Step 7: Based on the initial optimization scheme, select 2 to 4 groups of similar wire gauges and 2 to 4 groups of similar numbers of parallel windings to generate candidate schemes that meet the slot filling rate requirements;

[0078] Step 8: Use the finite element method to calculate the stator winding DC loss, eddy current loss and AC loss of the above scheme respectively;

[0079] Step 9: Use the thermal network method to calculate the stator and rotor temperature rise of the above scheme;

[0080] Step 10: Select the solution with the lowest stator winding AC loss and stator and rotor temperature rise as the combination of stator winding wire diameter and number of parallel windings.

[0081] Embodiment 2:

[0082] Taking a high-speed motor of a fuel cell air compressor with a peak speed of 100,000 rpm and a rated power of 35 kW as an example, the basic parameters of the motor are shown in Table 1, and the calculation conditions are shown in Table 2. The fast optimization method of the present invention is used to optimize the stator winding wire diameter and the number of parallel windings of this high-speed motor. In order to reduce the skin effect, the wire diameter should not be too large, but it is subject to the limitations of the manufacturing process and the wire diameter should not be too small. Considering both, the optimization interval and step size of the wire diameter setting are 0.5-1 mm and 0.01 mm, respectively, and the optimization interval and step size of the number of parallel windings are 5-30 and 1, respectively. That is, the full solution is shown in Table 3.

[0083] Table 1: Basic parameters of motor

[0084] name symbol Numeric unit Motor speed <![CDATA[N rpm ]]> 90000 rpm Phase current effective value <![CDATA[I rms ]]> 87 Arms Motor pole pairs p 1 - Number of conductors per slot N 8 - Number of parallel branches b 2 - Conductor full turn length <![CDATA[l turn ]]> 0.3828 m Effective length of conductor in slot l 0.06 m Gap between conductors in slot <![CDATA[d gap ]]> 0.05 mm Slot equivalent high h 15 mm Stator slot effective area <![CDATA[A n ]]> 80.1 mm^2 Conductor resistivity (25℃) ρ 1.68E-08 Ω*m

[0085] Table 2: Calculation conditions

[0086]

[0087] Table 3: Full solution

[0088]

[0089] Using formula (1), the above solutions are screened according to the slot filling rate ≤ 80%, and the slot filling rate of the candidate solutions is obtained, as follows: Figure 2 As shown,

[0090]

[0091] Among them, α is the stator slot filling rate; d wire A is the outer diameter of the enameled wire; n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot.

[0092] Using theoretical calculation formulas (2) to (4), the winding eddy current loss of each candidate solution is obtained, such as Figure 3 As shown,

[0093]

[0094]

[0095]

[0096] Among them, P eddy is the eddy current loss of the stator winding, N is the number of conductors per slot, a is the number of stator windings, l is the effective length of the conductor in the slot, ρ is the conductor resistivity, h is the equivalent slot height, p is the number of motor pole pairs, N rpm is the motor speed, ω is the angular frequency of the current in the conductor, d is the conductor diameter, B iis the magnetic field density of the i-th layer in the slot, n is the number of conductor distribution layers, d gap is the gap between conductors in the slot, d wire is the outer diameter of the enameled wire.

[0097] Using theoretical calculation formulas (5) and (6), the DC loss of the windings of each candidate solution is obtained, as follows: Figure 4 As shown,

[0098]

[0099]

[0100] Among them, P dc is the DC loss of the stator winding, N is the number of conductors per slot, a is the number of stator windings, l is the effective length of the conductor in the slot, ρ is the conductor resistivity, l turn is the conductor full turn length, R dc is the DC phase resistance of the stator winding, I rms is the effective value of the stator winding phase current, and b is the number of parallel branches.

[0101] Using the theoretical calculation formula (3), the winding AC loss of each candidate solution is obtained. The optimal initial solution with the minimum winding AC loss is the stator winding solution with a bare copper wire diameter of 0.75 mm, 10 windings, and a slot fill rate of 65.6%, as shown in Figure 5 As shown,

[0102] P ac =P dc +P eddy (7)

[0103] Among them, P ac is the stator winding AC loss, P dc is the stator winding DC loss, P eddy is the eddy current loss of the stator winding.

[0104] The reference wire gauge standard GB6109-2008 was consulted, and on the basis of the optimal solution, 0.71mm, 0.75mm, and 0.8mm bare copper wire diameter solutions were developed, and 9 candidate solutions with matching and winding numbers of 9, 10, and 11 were found. Since the slot fill rate of the solution with a wire diameter of 0.8mm and a winding number of 11 was 81%, which exceeded the requirement of 80%, there were finally 8 candidate solutions, as shown in Table 4.

[0105] Table 4: Candidate solutions

[0106]

[0107] The finite element method is used to scan and calculate the stator winding AC losses of the above 8 candidate solutions. The loss values ​​are shown in Table 5.

[0108] Table 5: Stator winding AC losses of candidate solutions

[0109]

[0110] The maximum stable temperatures of the stator windings and rotor permanent magnets of the eight candidate solutions are scanned and calculated using the thermal network method. The stable temperatures are shown in Table 6.

[0111] Table 6: Maximum stable temperature of stator winding and magnetic steel of candidate solutions

[0112]

[0113] The optimal winding scheme is to select the solution with the minimum stator winding AC loss and the minimum temperature rise of the motor stator and rotor, that is, the winding scheme with an enameled wire diameter of 0.789, a bare copper wire diameter of 0.71, a winding number of 11, and a slot fill rate of 64.5%.

[0114] Embodiment 3:

[0115] Taking the high-speed motor of a fuel cell air compressor with a peak speed of 100,000 rpm and a rated power of 35 kW as an example, the basic parameters of the motor are shown in Table 7, and the calculation conditions are shown in Table 8. The optimal solutions of the stator winding wire diameter and the number of parallel windings are calculated using the empirical formula method, the finite element scanning method, and the method of the present invention, respectively. The optimization speeds of the three methods are compared, and then the advantages and disadvantages of the optimal solutions obtained by each method in terms of motor loss, motor temperature rise, wire package size, stator winding weight, manufacturing process, etc. are compared.

[0116] The optimization process of the empirical formula method is as follows:

[0117] In order to make the bare copper wire diameter of the enameled wire smaller than the penetration depth of the skin effect in the conductor, the maximum wire diameter requirement is calculated using formula (8) to be r≤1.68mm.

[0118]

[0119] Among them, r is the bare copper wire radius of the conductor; ω is the current frequency in the conductor; μ is the magnetic permeability of the conductor; σ is the electrical conductivity of the conductor;

[0120] According to the wire gauge standard GB6109-2008, the commonly used wire diameters of 1.4mm, 1.5mm, and 1.6mm are selected according to the maximum wire diameter requirements. For these wire diameters, the appropriate number of parallel windings is selected to maximize the slot fill rate without exceeding 80%. Three feasible solutions are obtained, as shown in Table 7. Since the 1.6mm wire diameter solution has the highest slot fill rate, the solution with an enameled wire outer diameter of 1.67mm, a wire diameter of 1.6mm, a parallel winding number of 3, and a slot fill rate of 78.9% is selected as the optimal solution A.

[0121] Table 7: Feasible solutions of empirical formula method

[0122]

[0123] The optimization process of the finite element scanning method is as follows:

[0124] In order to reduce the skin effect, the wire diameter should not be too large, but it should not be too small due to the limitation of the manufacturing process. Taking both into consideration, the optimal range and step size of the wire diameter setting are 0.5-1mm and 0.01mm respectively, and the optimal range and step size of the winding number setting are 5-30 and 1 respectively. The whole scheme is shown in Table 8.

[0125] Table 8: Full solution

[0126]

[0127] Using formula (1), the above solutions are screened according to the slot full rate ≤ 80%, and the candidate full solutions are obtained as follows: Figure 2 As shown,

[0128]

[0129] Among them, α is the stator slot filling rate, d wire A is the outer diameter of the enameled wire, n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot.

[0130] The finite element method is used to scan and calculate the stator winding AC loss and stator and rotor temperature rise of each candidate solution one by one, and the optimal stator winding solution is obtained as follows:

[0131] Solution B: The outer diameter of the enameled wire is 0.789mm, the diameter of the bare copper wire is 0.71mm, the number of windings is 11, and the slot fill rate is 64.5%. This solution is the same as the optimal solution obtained by the fast optimization method.

[0132] In order to better evaluate the accuracy of the rapid optimization method, the initial optimal solution of the rapid optimization method is compared as Solution C, that is, Solution C is a stator winding solution with an outer diameter of 0.834 for the enameled wire, a diameter of 0.75 mm for the bare copper wire, 10 windings, and a slot fill rate of 65.6%.

[0133] The motor loss and motor efficiency of the combination of wire diameter and parallel winding number obtained by the three optimization methods are shown in Table 9. From this data, it can be concluded that:

[0134] a. The difference in wire diameter and number of parallel windings mainly affects the DC loss and eddy current loss of the winding, but has almost no effect on other losses;

[0135] b. The winding AC loss of Scheme A is about 108W higher than that of Scheme B, and the efficiency is correspondingly about 0.29% lower;

[0136] c. The winding AC loss of Scheme C is about 4W higher than that of Scheme B, which has almost negligible impact on the total loss and efficiency of the motor.

[0137] Table 9: Comparison of motor loss and motor efficiency

[0138]

[0139]

[0140] The temperature rise of the motor stator and rotor for the combination of wire diameter and parallel winding number obtained by the three optimization methods is shown in Table 10. From this data, it can be concluded that:

[0141] a. The difference in wire diameter and number of parallel windings will mainly affect the stable temperature rise of the stator winding, while the effect on the temperature rise of other components is small and even negligible;

[0142] b. The maximum temperature and average temperature of the stator winding of Scheme A are 16°C and 7.7°C higher than those of Scheme B, respectively;

[0143] c. The maximum temperature and average temperature of the stator winding of Scheme C are 0.8℃ and 0℃ higher than those of Scheme B, respectively, which has almost negligible impact on the motor.

[0144] Table 10: Comparison of motor stator and rotor temperature rise

[0145]

[0146]

[0147] The motor stator winding weight, total coil height and whole machine power density of the three optimization methods for the combination of wire diameter and parallel winding number are shown in Table 11. From this data, it can be concluded that:

[0148] a. The weight of the stator winding assembly of Scheme A is 0.235kg and 0.219kg higher than that of Scheme B and Scheme C, respectively;

[0149] b. The stator winding coil height of Scheme A is 5mm higher than that of Schemes B and C;

[0150] c. The air compressor power density of Scheme A is 0.05Kw / kg and 0.04Kw / kg lower than that of Scheme B and Scheme C respectively;

[0151] d. The stator winding assembly weight, coil height and total success rate density of the air compressor of Scheme B and Scheme C are basically the same.

[0152] Table 11: Comparison of motor stator winding weight, total coil height and overall power density

[0153]

[0154]

[0155] The above descriptions are merely embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structures made using the contents of the specification and drawings of the present invention, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for rapidly optimizing the wire diameter and the number of parallel windings of a high-speed motor stator winding, characterized in that: The rapid optimization method comprises the following steps: Step 1: Finite element modeling, divide the stator slots into 10 to 20 layers in the radial direction, and use the finite element method to calculate the magnetic flux density data of each layer in the stator slots; Step 2: Input the basic parameters of the motor and the magnetic flux density curve in the slot into the calculation program; Step 3: Set the optimization interval and step size of wire diameter and number of parallel windings; Step 4: Calculate the slot fullness rate in the optimization interval; Step 5: Calculate the stator winding DC loss, eddy current loss and AC loss of the above solution; Step 6: Take the solution with the smallest AC loss of the stator winding as the initial optimization solution; Step 7: Based on the initial optimization scheme, select 2 to 4 groups of similar wire gauges and 2 to 4 groups of similar numbers of parallel windings to generate candidate schemes that meet the slot filling rate requirements; Step 8: Use the finite element method to calculate the stator winding DC loss, eddy current loss and AC loss of the above scheme respectively; Stpe9: Calculate the stator and rotor temperature rise of the above scheme using the thermal network method; Step 10: Select the solution with the lowest stator winding AC loss and stator and rotor temperature rise as the combination solution of stator winding wire diameter and parallel winding number; In Step 5, the calculation formulas for stator winding DC loss, eddy current loss, and AC loss are as follows: P ac =P dc +P eddy ; Among them, P dc is the stator winding DC loss, P eddy is the stator winding eddy current loss, P ac is the AC loss of the stator winding, N is the number of conductors per slot, a is the number of stator windings, l is the effective length of the conductor in the slot, l turn is the conductor full turn length, ρ is the conductor resistivity, h is the slot equivalent height, p is the number of motor poles, N rpm is the motor speed, ω is the angular frequency of the current in the conductor, d is the conductor diameter, B i is the magnetic field density of the i-th layer in the slot, n is the number of conductor distribution layers, d gap is the gap between conductors in the slot, R dc is the DC phase resistance of the stator winding, I rms is the effective value of the stator winding phase current, b is the number of parallel branches, d is wire is the outer diameter of the enameled wire.

2. The method for rapidly optimizing the wire diameter and the number of parallel windings of a high-speed motor stator winding according to claim 1 is characterized in that: In Step 4, the calculation formula for the slot fill rate is as follows: Among them, α is the stator slot filling rate; d wire A is the outer diameter of the enameled wire; n is the effective slot area of ​​the stator, a is the number of stator windings, and N is the number of conductors per slot.

3. The method for rapidly optimizing the wire diameter and the number of parallel windings of a high-speed motor stator winding according to claim 1, characterized in that: In Step 3, the optimal interval and step size of the wire diameter are set to 0.3-1.5 mm and 0.01-0.1 mm, respectively, and the optimal interval and step size of the number of windings are set to 1-50 and 1, respectively.

Images