Brushless electro-magnetic synchronous motor system optimization design method based on magnetic coupling resonance

Abstract

The invention relates to the field of motors, in particular to a brushless electro-magnetic synchronous motor system optimization method based on magnetic coupling resonance. The invention provides a brushless electro-magnetic synchronous motor system optimization method based on magnetic coupling resonance. The brushless electro-magnetic synchronous motor system optimization method is used for improving the performance of a brushless electro-magnetic synchronous motor system. From the geometric structure and electromagnetic angle of the brushless electro-magnetic synchronous motor system, a design model of the 8-D brushless electro-magnetic synchronous motor system is established, and an optimization algorithm is adopted to optimize the 8-D design model. And aiming at the optimization result, taking the ratio of the mutual inductance variable quantity delta M to the distance variable quantity delta D as an optimization result evaluation condition. According to the method provided by the invention, verification is carried out on a model machine, and the system performance of the brushless electro-magnetic synchronous motor with magnetic coupling resonance is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of motors, and particularly to an optimization method for a brushless electrically excited synchronous motor system based on magnetic coupling resonance. Background Art

[0002] The brushless electrically excited synchronous motor does not require rare earth materials and has a low cost. In addition, the air-gap magnetic field of the brushless electrically excited synchronous motor is controllable, and it has the advantages of high power factor and adjustable power factor. However, the brushless electrically excited motor requires contact excitation structures such as brushes and slip rings to obtain current to establish an excitation magnetic field, and problems such as mechanical wear and electric sparks will be generated by the contact structure, which limits its application in special scenarios.

[0003] The use of magnetic coupling resonance wireless power transmission can eliminate contact excitation structures such as brushes and slip rings. Magnetic coupling resonance wireless power transmission utilizes the principle of resonance coupling to make the transmitting-end circuit and the receiving-end circuit have the same resonance frequency, and the brushless electrically excited synchronous motor serves as the load of the magnetic coupling resonance device. However, the transmission performance of the magnetic coupling resonance device is easily affected by factors such as the coupling coefficient, resonance frequency matching, external interference, and load size. For example, the offset of the coils at the transmitting end and the receiving end will cause a decrease in the coupling coefficient, and the design error of the inductor and capacitor will cause a mismatch in the resonance frequency, and the mismatch between the magnetic coupling resonance device and the brushless electrically excited synchronous motor.

[0004] In the process of coupling the magnetic coupling resonance device and the brushless electrically excited synchronous motor, the optimal design of a single component (such as the optimal design of the magnetic coupling resonance device and the optimal design of the brushless electrically excited synchronous motor) cannot fundamentally achieve the best performance of the brushless electrically excited synchronous motor system. How to optimize the design of the magnetic coupling resonance wireless power transmission device and the brushless electrically excited synchronous motor from the perspective of the brushless electrically excited synchronous motor system and improve the performance of the brushless electrically excited synchronous motor system requires further research. Summary of the Invention

[0005] In order to improve the performance of the magnetic coupling resonance brushless electrically excited synchronous motor system, the present invention optimizes the design from the geometric structure and electromagnetic angle of the magnetic coupling resonance brushless electrically excited synchronous motor. The present invention provides the following technical solutions:

[0006] An optimization method for a brushless electrically excited synchronous motor system based on magnetic coupling resonance, comprising the following steps:

[0007] Step 1: Establish a brushless electrically excited synchronous motor system based on magnetic coupling resonance. The brushless electrically excited synchronous motor system based on magnetic coupling resonance includes a magnetic coupling resonance device and a brushless electrically excited synchronous motor. The magnetic coupling resonance device includes a DC power supply Us, an inverter circuit, a resonance circuit, a transmitting coil, a receiving coil, and a rectifier circuit. The receiving coil and the rectifier circuit are installed on the rotating shaft of the brushless electrically excited synchronous motor. The brushless electrically excited synchronous motor includes a stator, a stator winding, a rotor, a rotor excitation winding, and a rotating shaft.

[0008] The resistance of the transmitting side of the magnetic coupling resonance device is R1, the resistance of the receiving side is R2, and the resonance frequency is ω.

[0009] The resistance of the rotor excitation winding is R L 。

[0010] Step 2: Establish an optimization parameter model for the 3-D magnetic coupling resonance device

[0011] The sizes of the transmitting coil and the receiving coil are the same.

[0012] The maximum outer radius of the coil is denoted as R c1 , the axial number of turns of the coil is N1, the radial number of turns is N2, the coil uses Litz wire with a diameter of D Litz , and the air gap interval between the Litz wires is Δ gap 。The minimum inner radius of the coil is denoted as R c2 , and can be calculated as:

[0013] R c2 =R c1 -N 1* D Litz (1)

[0014] The distance between any two points in the transmitting end coil and the receiving end coil is denoted as:

[0015]

[0016] The self-inductances of the transmitting coil and the receiving coil are denoted as L1 and L2, and the mutual inductance is denoted as M.

[0017] The optimization parameters of the magnetic coupling resonance device are R c1 、N1、N2.

[0018] Step 3: The power transmitted from the transmitting coil to the receiving coil is:

[0019]

[0020] The mutual inductance M between the transmitting coil and the receiving coil and the optimization parameters of the magnetic coupling resonance device are R c1 、N1、N2, and the calculation relationship is:

[0021]

[0022] Step 4: Establish an optimization parameter model for the 5-D electric excitation synchronous motor

[0023] The number of poles of the motor is p, and the circumferential angle θ occupied by each pole r= 360 / p, the number of slots is Z, and the circumferential angle occupied by each slot is θ s = 360 / Z.

[0024] The outer radius of the stator is R so , the outer radius of the rotor is R ro , the axial length is L Axial , the number of turns of the stator winding is N s , the number of turns of the rotor exciting winding is N r , the other dimensions of the stator and rotor are represented by the dimensionless ratios k si , k sy , k st , k so , k ri , k ry , k rt .

[0025] The inner diameter of the stator is:

[0026] R si = k si R so (6)

[0027] The thickness of the stator yoke is:

[0028]

[0029] The width of the stator tooth is:

[0030] W st = R si sin(k st θ s ) (8)

[0031] The stator slot opening is:

[0032]

[0033] The inner radius of the rotor is:

[0034] R ri = k ri R ro (10)

[0035] The depth of the rotor slot is:

[0036]

[0037] The thickness of the rotor yoke is:

[0038]

[0039] The width of the rotor tooth is:

[0040]

[0041] The width of the rotor pole shoe is:

[0042]

[0043] The optimized parameters of the electric excitation synchronous motor are R so , R ro , L Axial , N s , N r

[0044] Step Five: The output power of the magnetic coupling resonant brushless electric excitation synchronous motor system is:

[0045]

[0046] where n is the motor speed and T m is the torque.

[0047] The efficiency of the magnetic coupling resonant brushless electric excitation synchronous motor system is:

[0048]

[0049] Step Six: Determine the range of the optimized parameters and set the optimization goal of the brushless electric excitation synchronous motor system as the efficiency η sys and the power P sys .

[0050] Step Seven: Adopt the sampling method to extract n combinations of 8-D parameters, solve the results of the n parameter combinations, and establish an 8-D brushless electric excitation synchronous motor system surrogate model according to the solution results:

[0051]

[0052] Step Eight: Adopt the optimization algorithm to optimize the magnetic coupling resonant brushless electric excitation synchronous motor system and obtain the Pareto front.

[0053] Step Nine: For the Pareto optimization result in Step Seven, use the ratio of the mutual inductance change ΔM to the distance change ΔD as the condition for evaluating the final optimization result. The smaller the ratio, the higher the stability of the energy transmission between the transmitting coil and the receiving coil.

[0054] Step Ten: Obtain the final result.

[0055] The present invention conducts an optimized design on the brushless electric excitation synchronous motor system from the geometric structure and electromagnetic angle of the magnetic coupling resonant brushless electric excitation synchronous motor, which not only improves the output power and efficiency of the magnetic coupling resonant brushless electric excitation synchronous motor system, but also improves the transmission stability of the magnetic coupling device. Description of the Drawings

[0056] Figure 1 Flow chart of the optimization method for a brushless electrically excited synchronous motor system with magnetic coupling resonance

[0057] Figure 2 Schematic diagram of the structures of the transmitting coil and the receiving coil of the magnetic coupling device

[0058] Figure 3 Schematic diagram of the geometric structure of the motor stator

[0059] Figure 4 Schematic diagram of the geometric structure of the motor rotor

[0060] Figure 5 Schematic diagram of the coil structure before optimization

[0061] Figure 6 Schematic diagram of the coil structure after optimization

[0062] Figure 7 Schematic diagram of the Pareto optimization result

[0063] Figure 8 Schematic diagram of the ratio of ΔM to ΔD for different optimization results

[0064] Figure 9 Schematic diagram of the change in the output power of the system before and after optimization with respect to the distance between the transmitting coil and the receiving coil

[0065] Figure 10 Schematic diagram of the change in the system efficiency before and after optimization with respect to the distance between the transmitting coil and the receiving coil Detailed Implementation Manner

[0066] The present invention will be described in detail below with reference to specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0067] During the coupling process of the magnetic coupling resonance device and the electrically excited synchronous motor, the optimization design of a single component (such as the optimization design of the magnetic coupling resonance device or the optimization design of the electrically excited synchronous motor) cannot fundamentally achieve the best performance of the brushless electrically excited synchronous motor system. Refer to Figure 1As shown, an optimization method for a brushless electric-excitation synchronous motor system based on magnetic coupling resonance mainly includes establishing an optimization parameter model of a 3-D magnetic coupling device, establishing an optimization parameter model of a 5-D electric-excitation synchronous motor, determining the optimization parameter range and optimization objective, establishing an 8-D surrogate model of the brushless electric-excitation synchronous motor system, carrying out optimization using an optimization algorithm, and taking the ratio of the mutual inductance change ΔM to the distance change ΔD as the evaluation condition of the optimization result.

[0068] The sizes of the transmitting coil and the receiving coil are the same. The maximum outer radius of the coil is denoted as R c1 , and the minimum inner radius is denoted as R c2 . The axial number of turns of the coil is N1, and the radial number of turns is N2. The coil uses Litz wire with a diameter of D Litz . The air-gap interval between the Litz wires is Δ gap . The distance between any two points in the transmitting coil and the receiving coil is The self-inductances L1, L2 and M of the transmitting coil and the receiving coil. The optimization parameters of the magnetic coupling resonance device are R c1 , N1, N2.

[0069] The mutual inductance M between the transmitting coil and the receiving coil is:

[0070]

[0071] The power transmitted from the transmitting coil to the receiving coil is:

[0072]

[0073] The number of poles of the motor is p = 4, and the circumferential angle θ r occupied by each pole = 360 / p. The number of slots is Z = 18, and the circumferential angle θ s occupied by each slot = 360 / Z. The outer radius of the stator is R so , the outer radius of the rotor is R ro , the axial length is L Axial , the number of turns of the stator winding is N s , and the number of turns of the field winding is N r . The other dimensions of the stator and rotor are represented by the dimensionless ratios k si , k sy , k st , k so , k ri , k ry , k rt .

[0074] The inner diameter of the stator R si = k si R so , the thickness of the stator yoke The width of the stator tooth Wst = R si sin(k st θ s ), the stator slot opening The inner radius of the rotor R ri = k ri R ro , the rotor slot depth The thickness of the rotor yoke The width of the rotor tooth The width of the rotor pole shoe The optimized parameters of the electric excitation synchronous motor are that the outer radius of the stator is R so , the outer radius of the rotor is R ro , the axial length is L Axial , the number of turns of the stator winding is N s , the number of turns of the excitation winding is N r .

[0075] The output power of the magnetically coupled resonant brushless electric excitation synchronous motor system is:

[0076]

[0077] The efficiency of the magnetically coupled resonant brushless electric excitation synchronous motor system is:

[0078]

[0079] Table 1 Parameter ranges of each parameter of the 8-D design model of the brushless electric excitation synchronous motor system

[0080]

[0081] Using the Latin hypercube sampling method, 2000 combinations of 8-D parameters are extracted, and the results of 2000 parameter combinations are solved. According to the solution results, an 8-D brushless electric excitation synchronous motor system surrogate model is established.

[0082] Using the multi-objective genetic algorithm, the 8-D brushless electric excitation synchronous motor system surrogate model is optimized to obtain the Pareto optimization result. According to the optimization result, points 1-4 are selected, and the ratio of the mutual inductance change ΔM to the distance change ΔD is proposed as the condition for selecting the final optimization result. Figure 8 and Figure 9 are the comparisons of the efficiency and output power of the brushless electric excitation synchronous motor system before and after optimization. With the change of the distance between the transmitting coil and the receiving coil, the system efficiency and output power after optimization are effectively improved, and it has better output performance.

[0083] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Accordingly, it should be understood that numerous modifications may be made to the exemplary embodiments, and other arrangements may be devised, without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a separate embodiment may be used in other described embodiments.

Claims

1. A method for optimizing a brushless electrically excited synchronous motor system based on magnetic coupling resonance, characterized in that: Step 1: Establish a magnetically coupled resonant brushless electrically excited synchronous motor system, the magnetically coupled resonant brushless electrically excited synchronous motor system includes a magnetically coupled resonant device and an electrically excited synchronous motor, the magnetically coupled resonant device includes a DC power supply Us, an inverter circuit, a resonant circuit, a transmitting coil, a receiving coil, and a rectifier circuit, the receiving coil and the rectifier circuit are installed on the rotating shaft of the electrically excited synchronous motor, and the electrically excited synchronous motor includes a stator, a stator winding, a rotor, a rotor excitation winding, and a rotating shaft; The resistance of the transmitting side of the magnetic coupling resonance device is R1, the resistance of the receiving side is R2, and the resonance frequency is ω; The rotor excitation winding resistance is R L ; Step 2: Establishing the Optimized Parameter Model of 3-D Magnetic Coupled Resonance Device The transmitting coil and receiving coil are of the same size; The maximum outer radius of the coil is denoted by R c1 The axial number of turns of the coil is N1, the radial number of turns is N2, and the diameter of the coil is D Litz Litz lines, the air gap between the Litz lines is Δ gap , the minimum inner radius of the coil is denoted by R c2 , can be calculated as: R c2 =R c1 -N 1* D Litz (1) The distance between any two points in the transmitting coil and the receiving coil is recorded as: The self-inductance of the transmitting coil and the receiving coil are denoted as L1 and L2, and the mutual inductance is denoted as M The optimized parameters of the magnetic coupling resonance device are R c1 , N1, N2; Step 3: The power transmitted from the transmitting coil to the receiving coil is: The mutual inductance M of the transmitting coil and the receiving coil and the optimized parameter of the magnetic coupling resonance device are R c1 The calculation relationship between N1 and N2 is: Step 4: Establish 5-D electrically excited synchronous motor optimization parameter model The number of motor poles is p, and the circular angle occupied by each pole is θ r =360 / p, the number of slots is Z, and the circumferential angle occupied by each slot is θ s =360 / Z; The outer radius of the stator is R so , the outer radius of the rotor is R ro , axial length is L Axial , the number of stator winding turns is N s , the number of turns of the rotor excitation winding is N r , the other dimensions of the stator and rotor are given by the dimensionless ratio k si , k sy , k st , k so , k ri , k ry , k rt express; The inner diameter of the stator is: R si =k si R so (6) The thickness of the stator yoke is: The width of the stator teeth is: W st =R si sin(k st i s ) (8) The stator slot openings are: The inner radius of the rotor is: R ri =k ri R ro (10) The rotor slot depth is: The thickness of the rotor yoke is: The width of the rotor teeth is: The rotor pole shoe width is: The optimized parameters of the electrically excited synchronous motor are R so , R ro , L Axial 、N s 、N r Step 5: The output power of the magnetically coupled resonant brushless electrically excited synchronous motor system is: Where n is the motor speed, T m is the torque; The efficiency of the magnetically coupled resonant brushless electrically excited synchronous motor system is: Step 6: Determine the range of optimization parameters and determine the optimization target of the brushless electric excitation synchronous motor system as efficiency η sys and power P sys ; Step 7: Use the sampling method to extract n combinations of 8-D parameters, solve the results of n parameter combinations, and establish the 8-D brushless electric excitation synchronous motor system proxy model based on the solution results: Step 8: Use the optimization algorithm to optimize the magnetically coupled resonant brushless electrically excited synchronous motor system and obtain the Pareto frontier; Step 9: For the Pareto optimization result of step 7, the ratio of the mutual inductance change ΔM to the distance change ΔD is used as the condition for selecting the final optimization result. The smaller the ratio, the higher the stability of energy transmission between the transmitting coil and the receiving coil.

2. The method for optimizing a brushless electrically excited synchronous motor system based on magnetic coupling resonance according to claim 1, characterized in that The optimized parameters of the magnetic coupling resonance device are the outer radius of the coil, the axial number of turns of the coil, and the radial number of turns of the coil; the optimized parameters of the motor are the outer radius of the stator, the outer radius of the rotor, the axial length, the number of turns of the stator winding, and the number of turns of the excitation winding. The remaining parameters of the motor are expressed by dimensionless proportions.

3. The method for optimizing a brushless electrically excited synchronous motor system based on magnetic coupling resonance according to claim 1, characterized in that The power transmitted from the transmitting coil to the receiving coil is: The output power of the magnetically coupled resonant brushless electrically excited synchronous motor system is: The efficiency of the magnetically coupled resonant brushless electrically excited synchronous motor system is:

4. A method for optimizing a brushless electrically excited synchronous motor system based on magnetic coupling resonance according to claim 1, characterized in that The sampling method is used to extract n combinations of 8-D parameters, and the results of the n parameter combinations are solved. According to the solution results, the 8-D brushless electric excitation synchronous motor system proxy model is established:

5. The method for optimizing a brushless electrically excited synchronous motor system based on magnetic coupling resonance according to claim 1, characterized in that The ratio of the mutual inductance change ΔM to the distance change ΔD is used as the condition for selecting the final optimization result.

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