Hybrid excitation generator with low harmonic content

Abstract

The invention discloses a low-harmonic-content hybrid excitation generator, and belongs to the technical field of hybrid excitation generators. Comprising a generator shell, a front end cover and a rear end cover are arranged on the two end faces, in the vertical direction, of the generator shell respectively, a fan is arranged on the top face of the generator shell, a stator and a rotor are arranged in the generator shell, and the rotor comprises a rotating shaft; the rotating shaft is sequentially sleeved with a permanent magnet rotor, a magnetic isolation lining and a claw pole electro-magnetic rotor from top to bottom, and the permanent magnet rotor is of an asymmetric magnetic pole structure. Through the arrangement of the permanent magnet steel and the magnetic isolation air gap, an asymmetric magnetic pole structure with asymmetric same magnetic poles, asymmetric adjacent magnetic poles and asymmetric outer circle magnetic density of adjacent magnetic pole rotors of the permanent magnet rotor is achieved, the harmonic content of the whole machine is low, the output quality is high, the magnetic adjustment range is large, and the voltage stabilization performance is good.

Description

Technical Field

[0001] The invention relates to the technical field of generator internal structure, in particular to a low harmonic content hybrid excitation generator. Background Art

[0002] At present, the generators used in the range extender of the extended-range hybrid vehicle are mostly pure electric excitation generators and pure permanent magnet generators. Among them, the pure electric excitation generator uses an energized excitation coil to generate a magnetic field, and has good magnetic regulation characteristics, but large excitation losses, low power density, and low efficiency. The pure permanent magnet generator uses permanent magnet steel to generate a magnetic field, and has the advantages of high efficiency, high power density, and high reliability, but the magnetic field of the permanent magnet steel is difficult to adjust, and expensive control components are mostly used to control the output voltage, with a narrow control range and low control accuracy. Therefore, the hybrid excitation generator that uses an excitation coil and permanent magnet steel to jointly generate a magnetic field has both good magnetic regulation characteristics and high power density, and has become the main development direction of generators for range extenders. However, the synthetic magnetic field of the excitation magnetic field and the permanent magnetic field in the conventional hybrid excitation generator is more complex, the magnetic field distribution in the main air gap is uneven, and there are many high-order harmonics, which affect the output voltage quality of the whole machine and urgently need further improvement. Summary of the invention

[0003] The purpose of the present invention is to provide a low harmonic content hybrid excitation generator, which can solve the problems of complex synthetic magnetic field of conventional hybrid excitation generators, high harmonic content caused by uneven magnetic field distribution in the main air gap, and poor output voltage quality.

[0004] To achieve the above-mentioned purpose, the present invention provides a low harmonic content hybrid excitation generator, comprising a generator shell, wherein the two end surfaces of the generator shell in the vertical direction are respectively provided with a front cover and a rear cover, a top surface of the generator shell is provided with a fan, and a stator and a rotor are provided inside the generator shell, wherein the rotor comprises a rotating shaft, and the rotating shaft is sequentially provided with a permanent magnet rotor, a magnetic isolation bushing, and a claw pole electric excitation rotor from top to bottom, and the permanent magnet rotor is provided with an asymmetric magnetic pole structure.

[0005] Preferably, the permanent magnet rotor comprises a rotor core, the rotor core is laminated by a plurality of rotor punchings, a plurality of irregular through slots are provided inside the rotor core, permanent magnet steel and magnetic isolation air gaps are correspondingly provided in the irregular through slots, a plurality of pole shoes are provided on the outer edge of the rotor core, and the pole shoes are fixed to the outer edge of the rotor core by screws;

[0006] A plurality of magnetic force groups are formed by the permanent magnet steel and the magnetic isolation air gap, and a plurality of magnetic poles are formed on the outer edge of the permanent magnet rotor by the magnetic force groups. The number of the magnetic poles is set to an even number, and the N poles and the S poles are set in an alternating manner.

[0007] Preferably, the asymmetric magnetic pole structure is specifically as follows: an asymmetric magnetic pole structure in which the same magnetic pole is asymmetric, adjacent magnetic poles are asymmetric, and adjacent magnetic poles have asymmetric outer magnetic flux density of the rotor. According to the rule of magnetic pole asymmetry, the constraint formula of the magnetic flux of adjacent magnetic poles is as follows:

[0008]

[0009] In the above formula, φ ln is the magnetic flux on the left side of the nth rotor pole, φ fn is the magnetic flux on the right side of the nth rotor pole, φ θn is the magnetic flux within the range of angle θ from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole, φ θ(n+1) is the magnetic flux within the range of angle θ from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole, φ n is the magnetic flux of the nth rotor pole, φ n+1 is the magnetic flux of the n+1th rotor pole;

[0010] The constraint formula of the outer magnetic flux density of adjacent magnetic pole rotors is as follows:

[0011] ||B γn |-|B γ(n+1) ||≤0.3T;

[0012] In the above formula, |B γn | represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole at an angle of γ, |B γ(n+1) | represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole at an angle of γ.

[0013] Preferably, the number of magnetic poles of the rotor is set to eight, and two groups of four identical magnetic force groups are set, and the two groups of four magnetic force groups are arranged in a centrally symmetrical manner. The structures of the four magnetic force groups are as follows:

[0014] Magnetic group 1: The outer side of magnetic group 1 is set as S pole, including five through slots, corresponding to three rectangular permanent magnets and two magnetic isolation air gaps;

[0015] Magnetic group 2: The outer side of magnetic group 2 is set as N pole, with five through slots and a pole shoe, in which four rectangular permanent magnets and two magnetic air gaps are set;

[0016] Magnetic group three: The outer side of magnetic group three is set as S pole, and is provided with six through slots, in which four rectangular permanent magnets and two magnetic isolation air gaps are provided;

[0017] Magnetic group four: The outer side of magnetic group four is set as an N pole, and is provided with eight through slots, in which five permanent magnets and three magnetic isolation air gaps are provided.

[0018] Therefore, the present invention adopts the above-mentioned low harmonic content hybrid excitation generator, which has the following advantages:

[0019] The permanent magnet rotor poles are designed as a structure in which the pole structures of two pairs of N poles and S poles are different from each other, and the pole structures on the left and right sides of the radial center of the four poles are asymmetric. The four poles are arranged alternately to form an asymmetric pole structure in which the same poles are asymmetric and adjacent poles are asymmetric. This asymmetric pole structure can effectively improve the distribution of the rotor magnetic field in the main air gap, weaken the high-order harmonics generated by the stator slots and the non-closed outer surface of the rotor core, and improve the quality of the output voltage of the whole machine.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a side cross-sectional view of a generator in a low harmonic content hybrid excitation generator of the present invention;

[0022] Figure 2 It is a cross-sectional view of a rotor core in a low harmonic content hybrid excitation generator of the present invention;

[0023] Figure numerals: 1, rotating shaft; 2, front end cover; 3, claw-pole electric excitation rotor; 4, magnetic isolation bushing; 5, stator; 6, permanent magnet rotor; 7, rear end cover. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. The specific model specifications need to be selected and determined according to the actual specifications of the device, and the specific selection calculation structure adopts the existing technology in the field, so it will not be described in detail.

[0025] Example

[0026] like Figure 1-Figure 2As shown, the present invention provides a low harmonic content hybrid excitation generator, including a generator shell, two end surfaces of the generator shell in the vertical direction are respectively provided with a front cover 2 and a rear cover 7, a top surface of the generator shell is provided with a fan, the fan is used for heat dissipation of the generator, a stator 5 and a rotor are provided inside the generator shell, the rotor includes a rotating shaft 1, the rotating shaft 1 is sequentially provided with a permanent magnet rotor 6, a magnetic isolation bushing 4, and a claw pole electric excitation rotor 3 from top to bottom, the permanent magnet rotor 6 is provided with an asymmetric magnetic pole structure, and a unique function is achieved through this result;

[0027] The above-mentioned permanent magnet rotor 6 includes a rotor core, which is laminated by a plurality of rotor punchings, a plurality of irregular through slots are provided inside the rotor core, permanent magnet steel and magnetic isolation air gaps are provided in the irregular through slots, and a plurality of pole shoes are provided on the outer edge of the rotor core, which are fixed to the outer edge of the rotor core by screws;

[0028] Several magnetic groups are formed by permanent magnet steel and magnetic isolation air gaps, and several magnetic poles are formed on the outer edge of the permanent magnet rotor through the magnetic groups. The number of magnetic poles is set to an even number, and the N poles and S poles are set in an alternating manner.

[0029] The asymmetric magnetic pole structure of the permanent magnet rotor is as follows: an asymmetric magnetic pole structure with asymmetric same magnetic poles, asymmetric adjacent magnetic poles, and asymmetric magnetic flux density of adjacent magnetic pole rotor outer circles. According to the rule of magnetic pole asymmetry, the constraint formula of the magnetic flux of adjacent magnetic poles is as follows:

[0030]

[0031] In the above formula, φ ln is the magnetic flux on the left side of the nth rotor pole, φ fn is the magnetic flux on the right side of the nth rotor pole, φ θn is the magnetic flux within the range of angle θ from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole, φ θ(n+1) is the magnetic flux within the range of angle θ from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole, φ n is the magnetic flux of the nth rotor pole, φ n+1 is the magnetic flux of the n+1th rotor pole;

[0032] The constraint formula of the outer magnetic flux density of adjacent magnetic pole rotors is as follows:

[0033] ||B γn |-|B γ(n+1) ||≤0.3T;

[0034] In the above formula, |B γn| represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole at an angle of γ, |B γ(n+1) | represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole at an angle of γ.

[0035] In a specific application, the number of magnetic poles on the outer edge of the permanent magnet rotor is set to 8. According to the above constraints, one of the structures is obtained as follows: Figure 2 As shown, the corresponding interior is composed of two sets of four identical magnetic groups, and the two sets of magnetic groups are arranged in a centrally symmetrical manner. The structure of the four magnetic groups is as follows: Figure 2 In the diagram, starting from the S pole at 11 o'clock, the following are arranged clockwise:

[0036] Magnetic group 1: The outer side of magnetic group 1 is set as S pole, including five through slots, corresponding to three rectangular permanent magnets and two magnetic isolation air gaps;

[0037] Magnetic group 2: The outer side of magnetic group 2 is set as N pole, with five through slots and a pole shoe, in which four rectangular permanent magnets and two magnetic air gaps are set;

[0038] Magnetic group three: The outer side of magnetic group three is set as S pole, and is provided with six through slots, in which four rectangular permanent magnets and two magnetic isolation air gaps are provided;

[0039] Magnetic group four: The outer side of magnetic group four is set as an N pole, and is provided with eight through slots, in which five permanent magnets and three magnetic isolation air gaps are provided.

[0040] like Figure 2 As shown, in the eight-pole rotor core of the present embodiment, each set of four magnetic groups occupies a range of 180 degrees, and an eight-pole rotor is obtained in a centrally symmetrical manner. In the above scheme, it can be further expanded in the form of four magnetic groups to form a twelve-pole rotor and a sixteen-pole rotor, etc.

[0041] 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 low harmonic content hybrid excitation generator, characterized in that: It includes a generator shell, wherein the two end surfaces of the generator shell in the vertical direction are respectively provided with a front cover and a rear cover, the top surface of the generator shell is provided with a fan, the interior of the generator shell is provided with a stator and a rotor, the rotor includes a rotating shaft, and the rotating shaft is sequentially provided with a permanent magnet rotor, a magnetic isolation bushing, and a claw pole electric excitation rotor from top to bottom, and the permanent magnet rotor is provided with an asymmetric magnetic pole structure.

2. A low harmonic content hybrid excitation generator according to claim 1, characterized in that: The permanent magnet rotor comprises a rotor core, the rotor core is laminated by a plurality of rotor punchings, a plurality of irregular through slots are provided inside the rotor core, permanent magnet steel and magnetic isolation air gaps are provided in the irregular through slots, and a plurality of pole shoes are provided on the outer edge of the rotor core, and the pole shoes are fixed to the outer edge of the rotor core by screws; A plurality of magnetic force groups are formed by the permanent magnet steel and the magnetic isolation air gap, and a plurality of magnetic poles are formed on the outer edge of the permanent magnet rotor by the magnetic force groups. The number of the magnetic poles is set to an even number, and the N poles and the S poles are set in an alternating manner.

3. A low harmonic content hybrid excitation generator according to claim 2, characterized in that: The asymmetric magnetic pole structure is specifically as follows: an asymmetric magnetic pole structure in which the same magnetic pole is asymmetric, adjacent magnetic poles are asymmetric, and adjacent magnetic poles have asymmetric outer magnetic flux density. According to the rule of magnetic pole asymmetry, the constraint formula of the magnetic flux of adjacent magnetic poles is as follows: In the above formula, φ ln is the magnetic flux on the left side of the nth rotor pole, φ fn is the magnetic flux on the right side of the nth rotor pole, φ θn is the magnetic flux within the range of angle θ from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole, φ θ(n+1) is the magnetic flux within the range of angle θ from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole, φ n is the magnetic flux of the nth rotor pole, φ n+1 is the magnetic flux of the n+1th rotor pole; The constraint formula of the outer magnetic flux density of adjacent magnetic pole rotors is as follows: ||B γn |-|B γ(n+1) ||≤0.3T; In the above formula, |B γn | represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the right side of the nth rotor pole to the magnetic pole dividing line on the right side of the nth rotor pole at an angle of γ, |B γ(n+1) | represents the absolute value of the magnetic flux density at the outer circle of the rotor corresponding to a point within the range from the left side of the n+1th rotor pole to the magnetic pole dividing line on the left side of the n+1th rotor pole at an angle of γ.

4. A low harmonic content hybrid excitation generator according to claim 3, characterized in that: The number of magnetic poles of the rotor is set to eight, and two groups of four identical magnetic force groups are set. The two groups of four magnetic force groups are arranged in a centrally symmetrical manner. The structures of the four magnetic force groups are as follows: Magnetic group 1: The outer side of magnetic group 1 is set as S pole, including five through slots, corresponding to three rectangular permanent magnets and two magnetic isolation air gaps; Magnetic group 2: The outer side of magnetic group 2 is set as N pole, with five through slots and a pole shoe, in which four rectangular permanent magnets and two magnetic air gaps are set; Magnetic group three: The outer side of magnetic group three is set as S pole, and is provided with six through slots, in which four rectangular permanent magnets and two magnetic isolation air gaps are provided; Magnetic group four: The outer side of magnetic group four is set as an N pole, and is provided with eight through slots, in which five permanent magnets and three magnetic isolation air gaps are provided.

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