Method for calculating radial force of switched reluctance motor in multi-type air gap eccentric state

Abstract

The invention belongs to the technical field of motors, and discloses a method for calculating the radial force of a switched reluctance motor in a multi-type air gap eccentric state, and the method comprises the following steps: S1, building an inductance parameter sample set of a hub switched reluctance motor in an air gap eccentric state; s2, establishing a nonlinear model of the hub switch reluctance motor in an air gap eccentric state; s3, establishing a radial force calculation model of the hub switched reluctance motor in an air gap eccentric state; and S4, verifying the effectiveness of the radial force calculation model under the air gap eccentric state of the switched reluctance motor by the established radial force measurement rack. According to the method for calculating the radial force of the switched reluctance motor in the multi-type air gap eccentric state, the change characteristics of the radial force of the switched reluctance motor with different structure parameters in the multi-type air gap eccentric state are fully considered, and the radial force of the switched reluctance motor with different structure parameters in the air gap eccentric state can be accurately calculated; and the simulation time of the three-dimensional finite element model of the switched reluctance motor is reduced.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity conditions. Background Art

[0002] In recent years, the switched reluctance motor, as one of the ideal drive motor types for wheel hub motor driven electric vehicles, has the advantages of wide speed regulation range, high reliability and low cost, and has received extensive attention in the field of electric vehicle drive motors. However, in actual driving, due to road excitation, radial loads cause air gap eccentricity in the switched reluctance motor, resulting in unbalanced radial force that triggers vertical vibration of the wheel hub drive motor, affecting the vehicle's ride comfort. In the existing switched reluctance motor radial force calculation method, only the radial force under normal operation of the switched reluctance motor is calculated, ignoring the radial force change of the switched reluctance motor under the action of air gap eccentricity. At the same time, the analytical calculation of radial force under air gap eccentricity is considered, and the research is mostly focused on the radial force problem of a single winding under radial air gap eccentricity, and the influence of air gap eccentricity on the radial force of other winding phases is not fully considered. The analytical calculation of radial force involving multiple types of air gap eccentricity such as tilt is relatively rare.

[0003] Therefore, a radial force calculation method considering various air gap eccentricity states of the hub switched reluctance motor is constructed, the radial force variation of the switched reluctance motor is analyzed through simulation, and a theoretical basis is provided for the eccentricity failure of the hub switched reluctance motor, which is of great significance for promoting the further application of the switched reluctance motor. Summary of the invention

[0004] The purpose of the present invention is to provide a method for calculating the radial force of a switched reluctance motor under multiple types of air gap eccentricity states, which fully considers the changing characteristics of the radial force of the switched reluctance motor with different structural parameters under multiple air gap eccentricity states, can accurately calculate the radial force of the switched reluctance motor with different structural parameters under the air gap eccentricity state, and reduces the simulation time of the three-dimensional finite element model of the switched reluctance motor.

[0005] To achieve the above object, the present invention provides a method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity conditions, comprising the following steps:

[0006] S1, establishing a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state;

[0007] S2, establish a nonlinear model of the hub switched reluctance motor under the condition of air gap eccentricity;

[0008] S3, establishing a radial force calculation model for the hub switched reluctance motor under air gap eccentricity;

[0009] S4. The established radial force measurement bench verifies the validity of the radial force calculation model of the switched reluctance motor under the air gap eccentricity state.

[0010] Preferably, in step S1, a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state is obtained, and the specific process is as follows:

[0011] S11. For a switched reluctance motor with given structural parameters, use finite element software to calculate the phase inductance parameters of the switched reluctance motor winding under different currents and different rotor positions;

[0012] S12, obtaining a sample set of inductance parameters of the hub switched reluctance motor under air gap eccentricity by simulating and calculating winding phase inductance parameters under different radial air gap eccentricities;

[0013] The winding phase inductance parameter sample set includes winding phase inductances of different currents and three special rotor positions.

[0014] Preferably, in step S2, a nonlinear model of the hub switched reluctance motor under the air gap eccentricity state is established, including an electromagnetic coupling equation, a mechanical drive equation and a circuit drive equation; the specific process is as follows:

[0015] S221, the electromagnetic coupling equation of the switched reluctance motor is as follows:

[0016]

[0017] Among them, N r is the number of rotor salient poles; θ is the rotor position angle; i is the winding phase current; L n are the coefficients of the Fourier series; is the phase angle of the nth harmonic component; a n is the pole-to-pole inductance L a The fitting coefficient of the polynomial; b n is the pole-to-pole half-slot inductance L m Polynomial fitting coefficients, L u is the pole-to-slot inductance;

[0018] Pole-to-pole inductance L a , pole-to-pole half-slot inductance L m , Pole-to-slot inductance L u The Fourier series coefficients of are as follows:

[0019]

[0020] When the rotor position is at the pole-to-slot position, the pole-to-pole inductance value L a , pole-to-pole half-slot inductance L m It can be expressed as:

[0021]

[0022] Where N is i n The number of items;

[0023] The phase voltage balance equation of each winding of S222 and SRM and the phase current excitation equation of the single winding driven by the switched reluctance motor circuit together constitute the switched reluctance motor circuit driving equation;

[0024] The phase voltage balance equation of each winding of SRM is as follows:

[0025]

[0026] S222, the switched reluctance motor circuit drives a single winding phase current excitation equation as shown below:

[0027]

[0028] Among them, U k is the applied voltage of the k-phase winding of the motor; R k is the resistance of the k-phase winding of the motor; i k is the k-phase winding current of the motor; e k is the induced electromotive force of the k-phase winding of the motor; ψ k is the flux linkage of the k-phase winding of the motor; L k is the inductance of the k-th phase winding of the motor; k is the phase sequence of the switched reluctance motor;

[0029] S23, the mechanical drive equation of the switched reluctance motor is as follows:

[0030]

[0031] Among them, T e is the magnetostatic torque of the single-phase winding, F r is the radial force of the single-phase winding; W m is the magnetic energy of a single winding phase, obtained by partial differentiation of the winding phase flux ψ(θ,i) current.

[0032] Preferably, the winding phase flux and the winding phase torque are calculated according to the above electromagnetic coupling equation and mechanical drive equation, and the specific process is as follows:

[0033] S241. Calculate the winding phase flux by performing partial current differentiation on the winding phase inductance, as shown below:

[0034]

[0035] Where, ψ is the motor winding flux; c n =a n -1 / n is the inductance L a Polynomial fitting coefficients after partial differentiation of current; d n =bn -1 / n is the inductance L m Polynomial fitting coefficients after partial differentiation of current;

[0036] S242. Calculate the winding phase torque by the winding phase flux, as shown below:

[0037]

[0038] Among them, W m is the magnetic energy of a single winding phase.

[0039] Preferably, in step S3, a radial force calculation model is established when the hub switched reluctance motor has an eccentric air gap. The specific process is as follows:

[0040] S31, judging the air gap eccentricity fault type of the switched reluctance motor, the air gap eccentricity type of the switched reluctance motor;

[0041] S32, solving and calculating the air gap length under different air gap eccentricity types;

[0042] S33, based on the nonlinear model of the wheel hub switched reluctance motor under the air gap eccentricity state, solving the calculation result according to the air gap length, obtaining the radial force calculation model of the wheel hub switched reluctance motor under the air gap eccentricity state;

[0043] S34. Based on the nonlinear model of the hub switched reluctance motor under the air gap eccentricity state, according to the radial force calculation model of the hub switched reluctance motor under the air gap eccentricity state, the inductance, current and rotor position are output to the radial force calculation model, and the radial force calculation result under the air gap eccentricity is output under the action of current, inductance and rotor position to obtain the radial force change under the operating condition of the hub switched reluctance motor.

[0044] Preferably, in step S32, the air gap length under different air gap eccentricity types is solved and calculated, which specifically includes the following steps:

[0045] S321. Solve the radial air gap lengths of different winding phases as follows:

[0046]

[0047] B=L g ±(Vg)

[0048]

[0049] Where Δg is the air gap eccentricity of the switched reluctance motor, L g is the initial air gap length;

[0050] S322, solve the air gap length in the tilted air gap eccentric state, as shown below:

[0051]

[0052] Wherein, edge E is the distance from the boundary of the motor stator salient pole to the center of the switched reluctance motor; edge F is the distance between the point after the tilted air gap is eccentric and the initial point when there is no tilted air gap eccentricity; ω is the angle between edge E and the surface of the stator salient pole; ρ is the angle between the point after the tilted air gap is eccentric and the surface of the stator salient pole at the initial position; Δg AC is the length of the air gap eccentricity between winding phase A and winding phase B; Δ(H g -2cos(ρ)F) is the axial length of the motor corresponding to each air gap; I LgAC is the air gap length between the stator and the rotor in the state of inclined air gap eccentricity; α is the inclination angle between winding phase A and winding phase C and winding phase B; H g is the axial length of the switched reluctance motor; D s is the outer diameter of the motor stator;

[0053] S323. In order to quantify the relative displacement offset of the air gap between the stator and the rotor, the radial air gap eccentricity relative eccentricity ε is defined as follows:

[0054] ε=(Vg / L g )×100%.

[0055] Preferably, in step S33, the specific process of establishing the radial force calculation model under the air gap eccentricity state of the hub switched reluctance motor is as follows:

[0056] S331. The static magnetotorque and radial force of the kth phase under the air gap eccentricity state can be expressed as:

[0057]

[0058] Among them, L g is the initial air gap length; e n N r c n / 2;e 0 is 0; e 1 N r (c 1 -L u ) / 2; f n N r d n -e n ;f 0 is 0; f 1 N r (2d 1 -c 1 -L u ) / 2;

[0059] S332, radial force equation of switched reluctance motor under radial air gap eccentricity state, as shown below:

[0060]

[0061] S333, the radial force equation of the switched reluctance motor under the tilted air gap eccentric state is as follows:

[0062]

[0063] Preferably, in step S4, in the radial air gap eccentric state, the unbalanced torque in the radial eccentric state is as follows:

[0064]

[0065] Under the inclined air gap eccentric state, the unbalanced moment under the inclined eccentric state is as follows:

[0066] T u =T u(1) +T u(2)

[0067] T u(1) =∫ Hg |F r(1) -F r(u) |ds=∫ l |f r(1) -f r(u) |ds

[0068] T u(2) =∫ Hg |F r(2) -F r(m) |ds=∫ l |f r(2) -f r(m) |ds

[0069] Among them, F r(1) 、F r(2) f is the radial force at one end of the motor stator salient pole under the tilted air gap eccentricity state; r(1) 、f r(2) F is the radial force measurement result under the tilted air gap eccentricity state; r(u) and F r(m) is the radial force at one end of the motor stator salient pole in the state of no air gap eccentricity; f r(u) 、f r(m) is the radial force measurement result under the eccentric state without air gap; l is the distance between the two pressure points, which is 135mm.

[0070] Therefore, the present invention adopts the above-mentioned method for calculating the radial force of the switched reluctance motor under multiple types of air gap eccentricity states, establishes a nonlinear model of the switched reluctance motor under the air gap eccentricity state based on the virtual displacement principle, provides a dynamic model for studying the dynamic analysis of the hub motor drive vehicle system, and fully considers the changing characteristics of the radial force of the switched reluctance motor with different structural parameters under multiple air gap eccentricity states; only using the radial air gap eccentricity inductance data can accurately calculate the radial force of the switched reluctance motor with different structural parameters under the air gap eccentricity state, reducing the simulation time of the three-dimensional finite element model of the switched reluctance motor; the present invention calculates the radial force at different positions of the motor circumference according to the air gap length change and the winding phase inductance parameter sample set, and verifies the validity of the radial force calculation result through a radial force measurement bench.

[0071] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a flow chart of radial force calculation in the switched reluctance motor of the present invention under the condition of air gap eccentricity;

[0073] Figure 2 1 is a winding phase flux linkage diagram of the switched reluctance motor of the present invention in the air gap eccentric state; wherein, (a) is the winding phase eccentric inductance; (b) is the winding phase eccentric flux linkage;

[0074] Figure 3 1 is a schematic diagram of the air gap eccentricity of the hub switched reluctance motor of the present invention; wherein (a) is a normal state; (b) is a radial air gap eccentricity; (c) is an inclined air gap eccentricity;

[0075] Figure 4 The calculation principle and distribution diagram of the inclined air gap of the present invention are shown in FIG. 1 , wherein (a) is the calculation principle of the inclined air gap; (b) is the axial air gap distribution;

[0076] Figure 5 It is a schematic diagram of the air gap solution of winding A and winding phase C under the inclined air gap eccentricity state of the present invention;

[0077] Figure 6 Schematic diagram of a multi-type air gap eccentric radial force measurement rig of the present invention;

[0078] Figure 7 1 is a comparison diagram of the radial air gap eccentricity and the radial force measured by the method of the present invention; wherein (a) is the winding A phase; (b) is the winding B phase; (c) is the winding C phase; (d) is the winding D phase;

[0079] Figure 8 It is a comparison diagram of the tilted air gap eccentricity of the method of the present invention and the unbalanced radial moment measured in the test. DETAILED DESCRIPTION

[0080] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0081] like Figure 1 As shown, the present invention provides a method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states, comprising the following steps:

[0082] S1, establishing a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state;

[0083] S2, establish a nonlinear model of the hub switched reluctance motor under the condition of air gap eccentricity;

[0084] S3, establishing a radial force calculation model for the hub switched reluctance motor under air gap eccentricity;

[0085] S4. The established radial force measurement bench verifies the validity of the radial force calculation model of the switched reluctance motor under the air gap eccentricity state.

[0086] Example

[0087] S1. Obtain a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state.

[0088] S11. For a switched reluctance motor with given structural parameters, the finite element software is used to calculate the phase inductance parameters of the switched reluctance motor winding under different currents and different rotor positions.

[0089] S12. By simulating and calculating the winding phase inductance parameters under different radial air gap eccentricities, a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state is obtained.

[0090] Among them, the winding phase inductance parameter sample set mainly consists of winding phase inductances of different currents and three special rotor positions.

[0091] S2. Establish a nonlinear model of the hub switched reluctance motor under the air gap eccentricity state.

[0092] S21. Based on the obtained sample set of winding phase inductance parameters of the hub switched reluctance motor under the air gap eccentricity state, the Fourier series method is used to fit the sample set of winding phase inductance parameters of the switched reluctance motor based on the virtual displacement principle and the electromechanical energy conversion principle. The inductance of the three special rotor positions of the switched reluctance motor is mainly fitted, and the rotor positions are 0°, 15° and 30° respectively, and the current excitation source is 0-20A.

[0093] S22. At the same time, according to the winding phase inductance parameter sample set, the winding phase flux sample set and the winding phase torque sample set are derived, and a nonlinear model of the hub switched reluctance motor under the air gap eccentricity state is established, wherein the model mainly includes electromagnetic coupling equations, mechanical drive equations and circuit drive equations.

[0094] S221, the electromagnetic coupling equation of the switched reluctance motor is as follows:

[0095]

[0096] Among them, N r is the number of rotor salient poles; θ is the rotor position angle; i is the winding phase current; L n are the coefficients of the Fourier series; is the phase angle of the nth harmonic component; a n is the pole-to-pole inductance L a The fitting coefficient of the polynomial; b n is the pole-to-pole half-slot inductance L m Polynomial fitting coefficients, L u is the pole-to-slot inductance;

[0097] Pole-to-pole inductance L a , pole-to-pole half-slot inductance L m , Pole-to-slot inductance L u The Fourier series coefficients of are as follows:

[0098]

[0099] When the rotor position is at the pole-to-slot position, the pole-to-pole inductance value L a , pole-to-pole half-slot inductance L m It can be expressed as:

[0100]

[0101]

[0102] Where N is i n The number of items.

[0103] The phase voltage balance equations of each winding of S222 and SRM and the phase current excitation equation of the single winding driven by the switched reluctance motor circuit together constitute the switched reluctance motor circuit driving equation.

[0104] The phase voltage balance equation of each winding of SRM is as follows:

[0105]

[0106] The switched reluctance motor circuit drives a single winding phase current excitation equation as shown below:

[0107]

[0108] Among them, U k is the applied voltage of the k-phase winding of the motor; R k is the resistance of the k-phase winding of the motor; i kis the k-phase winding current of the motor; e k is the induced electromotive force of the k-phase winding of the motor; ψ k is the flux linkage of the k-phase winding of the motor; L k is the inductance of the k-th phase winding of the motor; k is the phase sequence of the switched reluctance motor.

[0109] S23, the mechanical drive equation of the switched reluctance motor is as follows:

[0110]

[0111] Among them, T e is the magnetostatic torque of the single-phase winding, F r is the radial force of the single-phase winding; W m is the magnetic energy of a single winding phase, obtained by partial differentiation of the winding phase flux ψ(θ,i) current.

[0112] S24. Calculate the winding phase flux and winding phase torque according to the above electromagnetic coupling equation and mechanical drive equation.

[0113] S241. Calculate the winding phase flux by performing partial current differentiation on the winding phase inductance, as shown below:

[0114]

[0115] Where, ψ is the motor winding flux; c n =a n -1 / n is the inductance L a Polynomial fitting coefficients after partial differentiation of current; d n =b n -1 / n is the inductance L m The polynomial fitting coefficients are obtained after partial differentiation of the current. Figure 2 As shown, the winding phase inductance and winding phase flux characteristic diagram under the air gap eccentricity state obtained according to the above method.

[0116] S242. Calculate the winding phase torque by the winding phase flux, as shown below:

[0117]

[0118] Among them, W m is the magnetic energy of a single winding phase.

[0119] S3. Establish a radial force calculation model for the hub switched reluctance motor under the air gap eccentricity state.

[0120] S31, judging the type of the air gap eccentricity fault of the switched reluctance motor, the type of the air gap eccentricity of the switched reluctance motor, such as Figure 3 shown.

[0121] S32. Calculate and solve the air gap length under different air gap eccentricity types.

[0122] S321. According to the circumferential angle distribution of the salient pole center of each stator winding phase about the Y axis, the radial air gap lengths of different winding phases are solved by using different radial air gap eccentricity lengths at the B phase position, as shown below:

[0123]

[0124] B=L g ±(Vg)

[0125]

[0126] Where Δg is the air gap eccentricity of the switched reluctance motor, L g is the initial air gap length.

[0127] S322, such as Figure 4 Hehe Figure 5 As shown in the figure, under the condition of tilted air gap eccentricity, the salient pole of winding phase B is also set to rotate tilted about the X-axis. At this moment, the D-phase rotor salient pole and stator salient pole perpendicular to phase B only rotate around the X-axis, which causes their air gap to change very little. Winding phase A and winding phase C have the same tilt angle α as winding phase B. Solve the air gap length under the state of tilted air gap eccentricity as shown below:

[0128]

[0129] Wherein, edge E is the distance from the boundary of the motor stator salient pole to the center of the switched reluctance motor; edge F is the distance between the point after the tilted air gap is eccentric and the initial point when there is no tilted air gap eccentricity; ω is the angle between edge E and the surface of the stator salient pole; ρ is the angle between the point after the tilted air gap is eccentric and the surface of the stator salient pole at the initial position; Δg AC is the length of the air gap eccentricity between winding phase A and winding phase B; Δ(H g -2cos(ρ)F) is the axial length of the motor corresponding to each air gap; I LgAC H is the air gap length between the stator and the rotor in the state of inclined air gap eccentricity; g is the axial length of the switched reluctance motor; D s is the outer diameter of the motor stator.

[0130] S323. In order to better quantify the relative displacement offset of the air gap between the stator and the rotor, the radial air gap eccentricity relative eccentricity ε is defined as follows:

[0131] ε=(Vg / L g )×100%

[0132] S33. Based on the nonlinear model of the hub switched reluctance motor under the air gap eccentricity state, the radial force calculation model of the hub switched reluctance motor under the air gap eccentricity state is obtained according to the calculation result of the air gap length.

[0133] S331. The static magnetotorque and radial force of the kth phase under the air gap eccentricity state can be expressed as:

[0134]

[0135] Among them, L g is the initial air gap length; e n N r c n / 2;e 0 is 0; e 1 N r (c 1 -L u ) / 2; f n N r d n -e n ;f 0 is 0; f 1 N r (2d 1 -c 1 -L u ) / 2.

[0136] S332, radial force equation of switched reluctance motor under radial air gap eccentricity state, as shown below:

[0137]

[0138] S333, the radial force equation of the switched reluctance motor under the tilted air gap eccentric state is as follows:

[0139]

[0140] S34. Based on the nonlinear model of the hub switched reluctance motor under the air gap eccentricity state, according to the radial force calculation model of the hub switched reluctance motor under the air gap eccentricity state, the inductance, current and rotor position are output to the radial force calculation model, and the radial force calculation result under the air gap eccentricity is output under the action of current, inductance and rotor position to obtain the radial force change under the operating condition of the hub switched reluctance motor.

[0141] S4. The established radial force measurement bench verifies the validity of the radial force calculation model of the switched reluctance motor under the air gap eccentricity state.

[0142] S41, such as Figure 6The schematic diagram of the multi-type air gap eccentricity radial force measurement bench shown in the figure completes the movement of radial air gap eccentricity and tilted air gap eccentricity of the switched reluctance motor by adjusting the bolts between the stator and rotor of the switched reluctance motor; and the radial force measurement of different winding phases of the switched reluctance motor is completed by adjusting the rotor rotation.

[0143] S42, in the radial air gap eccentric state, the unbalanced torque in the radial eccentric state is as follows:

[0144] T u =∫ l |F e -F 0 |ds=∫ h |F ue -F u0 |ds=∫ h |f e -f 0 |ds

[0145] The calculation method of the present invention is compared with the radial force measurement results of various types of air-gap eccentric switched reluctance motors. Figure 7 As shown in the results, it can be seen that the radial force test measurement results are in good agreement with the numerical analytical calculation results, which proves the accuracy of the radial force calculation results.

[0146] S43. In the state of tilted air gap eccentricity, the radial force of the switched reluctance motor will be output in the form of unbalanced radial torque. The unbalanced torque in the state of tilted eccentricity is as follows:

[0147] T u =T u(1) +T u(2)

[0148] T u(1) =∫ Hg |F r(1) -F r(u) |ds=∫ l |f r(1) -f r(u) |ds

[0149] T u(2) =∫ Hg |F r(2) -F r(m) |ds=∫ l |f r(2) -f r(m) |ds

[0150] Among them, F r(1) 、F r(2) f is the radial force at one end of the motor stator salient pole under the tilted air gap eccentricity state; r(1) 、f r(2)F is the radial force measurement result under the tilted air gap eccentricity state; r(u) and F r(m) is the radial force at one end of the motor stator salient pole in the state of no air gap eccentricity; f r(u) 、f r(m) is the radial force measurement result under the eccentric state without air gap; l is the distance between the two pressure points, which is 135mm.

[0151] The calculation method of the present invention is compared with the radial force measurement results of various types of air-gap eccentric switched reluctance motors. Figure 8 shown.

[0152] Therefore, the present invention adopts the above-mentioned method for calculating the radial force of the switched reluctance motor under multiple types of air gap eccentricity states, establishes a nonlinear model of the switched reluctance motor under the air gap eccentricity state based on the virtual displacement principle, provides a dynamic model for studying the dynamic analysis of the hub motor drive vehicle system, and fully considers the changing characteristics of the radial force of the switched reluctance motor with different structural parameters under multiple air gap eccentricity states; only using the radial air gap eccentricity inductance data can accurately calculate the radial force of the switched reluctance motor with different structural parameters under the air gap eccentricity state, reducing the simulation time of the three-dimensional finite element model of the switched reluctance motor; the present invention calculates the radial force at different positions of the motor circumference according to the air gap length change and the winding phase inductance parameter sample set, and verifies the validity of the radial force calculation result through a radial force measurement bench.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states, characterized in that: The following steps are involved: S1, establishing a sample set of inductance parameters of the hub switched reluctance motor under the air gap eccentricity state; S2, establish a nonlinear model of the hub switched reluctance motor under the condition of air gap eccentricity; S3, establishing a radial force calculation model for the hub switched reluctance motor under air gap eccentricity; S4. The established radial force measurement bench verifies the validity of the radial force calculation model of the switched reluctance motor under the air gap eccentricity state.

2. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 1, characterized in that: In step S1, the inductance parameter sample set of the hub switched reluctance motor under the air gap eccentricity state is obtained, and the specific process is as follows: S11. For a switched reluctance motor with given structural parameters, use finite element software to calculate the phase inductance parameters of the switched reluctance motor winding under different currents and different rotor positions; S12, obtaining a sample set of inductance parameters of the hub switched reluctance motor under air gap eccentricity by simulating and calculating winding phase inductance parameters under different radial air gap eccentricities; The winding phase inductance parameter sample set includes winding phase inductances of different currents and three special rotor positions.

3. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 1, characterized in that: In step S2, a nonlinear model of the hub switched reluctance motor under the air gap eccentricity state is established, including electromagnetic coupling equations, mechanical drive equations and circuit drive equations; the specific process is as follows: S221, the electromagnetic coupling equation of the switched reluctance motor is as follows: Among them, N r is the number of rotor salient poles; θ is the rotor position angle; i is the winding phase current; L n are the coefficients of the Fourier series; is the phase angle of the nth harmonic component; a n is the pole-to-pole inductance L a The fitting coefficient of the polynomial; b n is the pole-to-pole half-slot inductance L m Polynomial fitting coefficients, L u is the pole-to-slot inductance; Pole-to-pole inductance L a , pole-to-pole half-slot inductance L m , Pole-to-slot inductance L u The Fourier series coefficients of are as follows: When the rotor position is at the pole-to-slot position, the pole-to-pole inductance value L a , pole-to-pole half-slot inductance L m It can be expressed as: Where N is i n The number of items; The phase voltage balance equation of each winding of S222 and SRM and the phase current excitation equation of the single winding driven by the switched reluctance motor circuit together constitute the switched reluctance motor circuit driving equation; The phase voltage balance equation of each winding of SRM is as follows: S222, the switched reluctance motor circuit drives a single winding phase current excitation equation as shown below: Among them, U k is the applied voltage of the k-phase winding of the motor; R k is the resistance of the k-phase winding of the motor; i k is the k-phase winding current of the motor; e k is the induced electromotive force of the k-phase winding of the motor; ψ k is the flux linkage of the k-phase winding of the motor; L k is the inductance of the k-th phase winding of the motor; k is the phase sequence of the switched reluctance motor; S23, the mechanical drive equation of the switched reluctance motor is as follows: Among them, T e is the magnetostatic torque of the single-phase winding, F r is the radial force of the single-phase winding; W m is the magnetic energy of a single winding phase, obtained by partial differentiation of the winding phase flux ψ(θ,i) current.

4. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 3 is characterized in that: According to the above electromagnetic coupling equation and mechanical drive equation, the winding phase flux and winding phase torque are calculated. The specific process is as follows: S241. Calculate the winding phase flux by performing partial current differentiation on the winding phase inductance, as shown below: Where, ψ is the motor winding flux; c n =a n -1 / n is the inductance L a Polynomial fitting coefficients after partial differentiation of current; d n =b n -1 / n is the inductance L m Polynomial fitting coefficients after partial differentiation of current; S242. Calculate the winding phase torque by the winding phase flux, as shown below: Among them, W m is the magnetic energy of a single winding phase.

5. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 1, characterized in that: In step S3, a radial force calculation model is established when the hub switched reluctance motor has an eccentric air gap. The specific process is as follows: S31, judging the air gap eccentricity fault type of the switched reluctance motor, the air gap eccentricity type of the switched reluctance motor; S32, solving and calculating the air gap length under different air gap eccentricity types; S33, based on the nonlinear model of the wheel hub switched reluctance motor under the air gap eccentricity state, solving the calculation result according to the air gap length, obtaining the radial force calculation model of the wheel hub switched reluctance motor under the air gap eccentricity state; S34. Based on the nonlinear model of the hub switched reluctance motor under the air gap eccentricity state, according to the radial force calculation model of the hub switched reluctance motor under the air gap eccentricity state, the inductance, current and rotor position are output to the radial force calculation model, and the radial force calculation result under the air gap eccentricity is output under the action of current, inductance and rotor position to obtain the radial force change under the operating condition of the hub switched reluctance motor.

6. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 5, characterized in that: In step S32, the air gap length under different air gap eccentricity types is solved and calculated, which specifically includes the following steps: S321. Solve the radial air gap lengths of different winding phases as follows: B=L g ±(Vg) Where Δg is the air gap eccentricity of the switched reluctance motor, L g is the initial air gap length; S322, solve the air gap length in the tilted air gap eccentric state, as shown below: Wherein, edge E is the distance from the boundary of the motor stator salient pole to the center of the switched reluctance motor; edge F is the distance between the point after the tilted air gap is eccentric and the initial point when there is no tilted air gap eccentricity; ω is the angle between edge E and the surface of the stator salient pole; ρ is the angle between the point after the tilted air gap is eccentric and the surface of the stator salient pole at the initial position; Δg AC is the length of the air gap eccentricity between winding phase A and winding phase B; Δ(H g -2cos(ρ)F) is the axial length of the motor corresponding to each air gap; I LgAC is the air gap length between the stator and the rotor in the state of inclined air gap eccentricity; α is the inclination angle between winding phase A and winding phase C and winding phase B; H g is the axial length of the switched reluctance motor; D s is the outer diameter of the motor stator; S323. In order to quantify the relative displacement offset of the air gap between the stator and the rotor, the radial air gap eccentricity relative eccentricity ε is defined as follows: ε=(Vg / L g )×100%。 7. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 5, characterized in that: In step S33, the specific process of establishing the radial force calculation model under the air gap eccentricity state of the hub switched reluctance motor is as follows: S331. The static magnetotorque and radial force of the kth phase under the air gap eccentricity state can be expressed as: Among them, L g is the initial air gap length; e n N r c n / 2; e0 is 0; e1 is N r (c1-L u ) / 2; f n N r d n -e n ; f0 is 0; f1 is N r (2d1-c1-L u ) / 2; S332, radial force equation of switched reluctance motor under radial air gap eccentricity state, as shown below: S333, the radial force equation of the switched reluctance motor under the tilted air gap eccentric state is as follows:

8. The method for calculating radial force of a switched reluctance motor under multiple types of air gap eccentricity states according to claim 1, characterized in that: In step S4, in the radial air gap eccentric state, the unbalanced torque in the radial eccentric state is as follows: T u =∫ l |F e -F0|ds=∫ h |F ue -F u0 |ds=∫ h |f e -f0|ds Under the inclined air gap eccentric state, the unbalanced moment under the inclined eccentric state is as follows: T u =T u(1) +T u(2) T u(1) =∫ Hg |F r(1) -F r(u) |ds=∫ l |f r(1) -f r(u) |ds T u(2) =∫ Hg |F r(2) -F r(m) |ds=∫ l |f r(2) -f r(m) |ds Among them, F r(1) 、F r(2) f is the radial force at one end of the motor stator salient pole under the tilted air gap eccentricity state; r(1) 、f r(2) F is the radial force measurement result under the tilted air gap eccentricity state; r(u) and F r(m) is the radial force at one end of the motor stator salient pole in the state of no air gap eccentricity; f r(u) 、f r(m) is the radial force measurement result under the eccentric state without air gap; l is the distance between the two pressure points, which is 135mm.

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