A solid rotor induction motor rotor parameter correction calculation method

Abstract

The application discloses a kind of solid rotor induction motor rotor parameter correction calculation methods, suitable for various capacity smooth solid rotor induction motor.First, according to the characteristics of solid rotor induction motor, the correction coefficient of axial end effect, skin effect, saturation effect and hysteresis effect is given.Then, based on the two-dimensional electromagnetic field theory, the analytical relationship of excitation branch parameters is obtained.Finally, according to the electromagnetic characteristics of solid rotor ferromagnetic material, the analytical relationship of rotor parameters is given respectively, and the method provides a new theoretical method for the design of solid rotor induction motor.

Description

Technical Field

[0001] This invention relates to the field of motor design and analysis, and in particular to a method for calculating the correction coefficients and parameters of the unique electromagnetic phenomena of a solid rotor induction motor. Background Technology

[0002] Solid rotor induction motors can frequently start under heavy loads and operate in braking mode for extended periods, making them suitable for torque motors and power equipment. Compared to permanent magnet motors and squirrel-cage motors, solid rotor induction motors offer advantages such as simple structure, low cost, high mechanical strength, corrosion resistance, and high reliability, making them widely used in medium- and high-speed motor applications. Obtaining accurate parameters for solid rotor induction motors through theoretical analysis facilitates rapid prototyping of the motor based on the torque curve required for the application.

[0003] Existing parameter calculations often utilize theoretical calculation methods for rotating induction motors to obtain the excitation resistance R in the T-type equivalent circuit of the induction motor. o Magnetizing Reactance X o Parameters such as rotor leakage inductance X2 and rotor resistance R2, etc. Figure 1 As shown, although the above method can obtain the approximate parameters of the motor, it does not take into account the influence of rotor magnetic saturation, skin effect, hysteresis effect and axial end effect unique to solid rotor induction motors on the parameters. Summary of the Invention

[0004] The purpose of this invention is to provide a method for calculating and correcting rotor parameters of a solid rotor induction motor.

[0005] The first step is to derive the correction coefficients for the rotor impedance parameters based on two-dimensional electromagnetic field theory. The resistance correction coefficient K is then considered after taking saturation effects into account. rs Reactance correction factor K xs They are respectively:

[0006]

[0007]

[0008] in:

[0009]

[0010] In equations (1) to (3) above, Δ k denoted as the theoretical penetration depth, i.e., the depth at which the electromagnetic wave decays to zero when magnetic saturation is considered; n is the order of the magnetization curve of the rotor ferromagnetic material when expressed as a higher-order parabola; μ2 is the absolute permeability of the rotor surface; s is the slip; ω1 is the angular frequency of the power supply; π is pi; τ is the stator pole pitch; σ2 is the conductivity of the rotor material; and Δ is the penetration depth of the rotor material.

[0011] Resistance correction factor K considering hysteresis effect rh and reactance correction factor K xh They are respectively:

[0012]

[0013]

[0014] in:

[0015]

[0016] In equations (4) to (6) above, X 2e Rotor reactance considering saturation and skin effects; R 2e The rotor resistance is calculated considering saturation and skin effects; φ is the hysteresis loss angle of the rotor material.

[0017] Correction factor K considering skin effect s for:

[0018]

[0019] Where D2 is the outer diameter of the rotor core; Δ is the penetration depth of the rotor material, which is defined in equation (3).

[0020] Correction factor K considering axial end effect e for:

[0021]

[0022] Where g is the electromagnetic air gap length; L e The effective length of the rotor; μ r denoted as the relative permeability of the rotor material; a is defined in equation (3).

[0023] Neglecting excitation losses, i.e., R o =0, excitation impedance Z o It can be approximated as:

[0024]

[0025] Where D1 is the stator inner diameter; K c K is the Cartesian coefficient; N1 is the number of turns in series per phase of the stator winding; w1 is the fundamental winding coefficient of the stator winding; j is the imaginary symbol; a is defined in equation (3).

[0026] The second step, in a solid rotor induction motor, after considering the effects of saturation, skin effect, hysteresis, and axial end effect, yields the equivalent values ​​of the rotor resistance R2 and reactance X2 on the stator side:

[0027]

[0028]

[0029] Where m is the number of phases of the stator winding.

[0030] This invention has the following advantages: Addressing the problem that classic methods for calculating rotor parameters of cage-type induction motors do not consider the unique rotor magnetic saturation, skin effect, hysteresis effect, and axial end effect in solid rotor induction motors, this method, based on two-dimensional electromagnetic field theory, derives correction coefficients and excitation reactance that take into account the above effects, thus avoiding calculation errors caused by the unique electromagnetic effects in solid rotor induction motors. Attached Figure Description

[0031] Figure 1 T-type equivalent circuit of induction motor. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0033] like Figure 1 As shown, the T-type equivalent circuit of the induction motor used in this invention includes: the stator resistor R1 and the stator leakage reactance X1 are connected in series and then connected to two parallel branches, namely the excitation branch and the secondary branch; the excitation branch is connected to the excitation resistor R. o and excitation reactance X o It is configured in series, with the rotor branch consisting of the rotor resistance R2 / s and the rotor reactance X2 connected in series.

[0034] This invention provides a method for calculating and correcting rotor parameters of a solid rotor induction motor. It includes the following steps:

[0035] The first step is to derive the correction coefficients for the rotor impedance parameters based on two-dimensional electromagnetic field theory. The resistance correction coefficient K is then considered after taking saturation effects into account. rs Reactance correction factor K xs They are respectively:

[0036]

[0037]

[0038] in:

[0039]

[0040] In equations (1) to (3) above, Δ k denoted as the theoretical penetration depth, i.e., the depth at which the electromagnetic wave decays to zero when magnetic saturation is considered; n is the order of the magnetization curve of the rotor ferromagnetic material when expressed as a higher-order parabola; μ2 is the absolute permeability of the rotor surface; s is the slip; ω1 is the angular frequency of the power supply; π is pi; τ is the stator pole pitch; σ2 is the conductivity of the rotor material; and Δ is the penetration depth of the rotor material.

[0041] Resistance correction factor K considering hysteresis effect rh and reactance correction factor K xh They are respectively:

[0042]

[0043]

[0044] in:

[0045]

[0046] In equations (4) to (6) above, X 2e Rotor reactance considering saturation and skin effects; R 2e The rotor resistance is calculated considering saturation and skin effects; φ is the hysteresis loss angle of the rotor material.

[0047] Correction factor K considering skin effect s for:

[0048]

[0049] Where D2 is the outer diameter of the rotor core; Δ is the penetration depth of the rotor material, which is defined in equation (3).

[0050] Correction factor K considering axial end effect e for:

[0051]

[0052] Where g is the electromagnetic air gap length; L e The effective length of the rotor; μ r denoted as the relative permeability of the rotor material; a is defined in equation (3).

[0053] Neglecting excitation losses, i.e., R o =0, excitation impedance Z o It can be approximated as:

[0054]

[0055] Where D1 is the stator inner diameter; Kc K is the Cartesian coefficient; N1 is the number of turns in series per phase of the stator winding; w1 is the fundamental winding coefficient of the stator winding; j is the imaginary symbol; a is defined in equation (3).

[0056] The second step, in a solid rotor induction motor, after considering the effects of saturation, skin effect, hysteresis, and axial end effect, yields the equivalent values ​​of the rotor resistance R2 and reactance X2 on the stator side:

[0057]

[0058]

[0059] Where m is the number of phases of the stator winding.

[0060] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes will be obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A method for calculating and correcting rotor parameters of a solid rotor induction motor, characterized in that, The first step is to derive the correction coefficients for the rotor impedance parameters based on two-dimensional electromagnetic field theory. These correction coefficients include the resistance correction coefficient K, which considers the saturation effect. rs Reactance correction factor K xs The resistance correction factor K considering the hysteresis effect rh and reactance correction factor K xh Considering the skin effect, the correction factor K s Correction factor K considering axial end effect e ; The second step is to calculate the rotor resistance R2 and reactance X2 referred to the stator side in the solid rotor induction motor after considering the above correction coefficients for saturation effect, skin effect, hysteresis effect and axial end effect. In the first step, the resistance correction factor K is considered after taking into account the saturation effect. rs Reactance correction factor K xs They are respectively: （1） （2） in: （3） In equations (1) to (3) above, Δ k Δ is the theoretical penetration depth, which is the depth at which the electromagnetic wave decays to zero when magnetic saturation is considered; n is the order of the magnetization curve of the rotor ferromagnetic material when expressed as a high-order parabola; μ2 is the absolute permeability of the rotor surface; s is the slip; ω1 is the power supply angular frequency; π is pi; τ is the stator pole pitch; σ2 is the conductivity of the rotor material; Δ is the penetration depth of the rotor material. Resistance correction factor K considering hysteresis effect rh and reactance correction factor K xh They are respectively: （4） （5） in: （6） In equations (4) to (6) above, X 2e Rotor reactance considering saturation and skin effects; R 2e The rotor resistance is calculated considering saturation and skin effects; ϕ is the hysteresis loss angle of the rotor material. Correction factor K considering skin effect s for: （7） Where D2 is the outer diameter of the rotor core; Δ is the penetration depth of the rotor material, which has been defined in equation (3); Correction factor K considering axial end effect e for: （8） Where g is the electromagnetic air gap length; L e μ is the effective length of the rotor. r Let be the relative permeability of the rotor material; a is defined in equation (3); Neglecting excitation losses, i.e., R o =0, excitation impedance Z o It can be approximated as: （9） Where D1 is the stator inner diameter; K c K is the Cartesian coefficient; N1 is the number of turns in series per phase of the stator winding; w1 is the fundamental winding coefficient of the stator winding; j is the imaginary symbol; a is defined in equation (3); μ0 is the vacuum permeability; m is the number of phases of the stator winding.

2. The method for correcting and calculating rotor parameters of a solid rotor induction motor according to claim 1, characterized in that, In the second step, the rotor resistance R2 and reactance X2 referred to the stator side are calculated as follows: （10） （11）。

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