Axial magnetic flux hybrid excitation starter generator for range extender

Abstract

The invention discloses an axial magnetic flux hybrid excitation starter generator for a range extender, and belongs to the technical field of new energy automobile electric appliances. The starter generator comprises a rotor disc, a first stator disc, a second stator disc, a shell assembly and a power transmission unit, the rotor disc is located between the first stator disc and the second stator disc, the shell unit wraps the rotor disc, the first stator disc and the second stator disc, and the rotor disc and an engine assembly are connected through the power transmission unit. A first air gap is formed between the first stator disc and the rotor disc, a second air gap is formed between the second stator disc and the rotor disc, and the permanent magnet and the electro-magnetic field form a resultant magnetic field in the two air gaps. Two functions of starting and power generation can be realized, a starter and a generator are integrated, the integration level is high, the power density is high, the magnetic field adjustment range is wide, the advantages of small axial size and compact structure of an axial motor can be effectively utilized, and the advantage of convenience in adjustment of an air-gap magnetic field of a hybrid excitation motor is also effectively exerted.

Description

Technical Field

[0001] The present invention relates to an axial flux hybrid excitation starting generator for a range extender, belonging to the technical field of new energy vehicle electrical appliances. Background Art

[0002] The widespread use of automobiles has exacerbated the consumption of oil resources. At the same time, due to the harmful gases emitted by the operation of engines, an increasingly serious pollution problem has been caused. New energy vehicles have become the main development direction of the current automotive industry. However, due to the technical problems of power batteries being difficult to break through in a short time, pure electric vehicles have disadvantages such as short lifespan, large size, long charging time, and short driving range. Therefore, hybrid electric vehicles are currently the most industrialized and market-oriented new energy vehicle development models. Among them, extended-range electric vehicles (EREV) combine the advantages of traditional internal combustion engines and electric motors, providing higher fuel efficiency and lower emissions. Compared with pure electric vehicles, the addition of a range extender greatly reduces the number of power batteries used and solves the problem of short driving range of pure electric vehicles.

[0003] An extended-range electric vehicle adds an auxiliary power generation device - a range extender on the basis of a pure electric vehicle. As the core component of the range extender, the starting generator mainly has two forms: an electric excitation starting generator and a permanent magnet starting generator. The electric excitation starting generator has the disadvantages of large excitation loss and low output efficiency; the permanent magnet starting generator has the disadvantages of difficult output voltage stability and complex control system. Therefore, a hybrid excitation starting generator that jointly provides a magnetic field by a permanent magnet magnetic potential source and an electric excitation magnetic potential source is an important development direction for the starting generator of the range extender.

[0004] Currently, the starting generator for the range extender mainly uses a radial flux motor. The axial size of this type of motor is relatively large. Since the axial size of the range extender compartment is small, the performance of the motor is restricted. However, the axial flux motor has the characteristics of compact structure, flat and ultra-thin, small volume, light weight, and high power density, and is more suitable for use in the starting generator of the range extender.

[0005] In the aspect of axial flux hybrid excitation motors, the existing related applications mainly include the invention patent application with the application number 201310301385.0: a double-stator disc-type hybrid excitation motor. The hybrid excitation motor of this application includes two stators, permanent magnets, three-phase concentrated armature windings, single-phase concentrated excitation windings, and a rotor. The hybrid excitation motor of this application adopts a double-stator disc-type structure, has the advantages of a hybrid excitation motor, and has a simple structure and is suitable for high-speed operation. In addition, the invention patent application with the application number 202010365668.1: a double-stator single-rotor axial magnetic field hybrid excitation synchronous motor. This motor includes two stator discs, a rotor disc, a rotating shaft, two bearings, a front end cover housing, a rear end cover housing, and a resolver. The hybrid excitation motor of this application adopts a stator single-rotor structure and has the advantages of a wide magnetic field regulation range, less permanent magnet consumption, small axial dimensions, and high reliability.

[0006] The axial flux hybrid excitation starting generator for a range extender of the present invention combines the advantages of convenient air-gap magnetic field regulation of a hybrid excitation motor and the characteristics of small axial dimensions and simple structure of an axial motor. The rotor is a hybrid excitation axial flux rotor structure, axially located between the first stator disc and the second stator disc, forming a double-stator disc-type structure, and placing the main heat-generating component, the armature winding, on the outside, improving the heat dissipation effect.

[0007] At present, after domestic and foreign searches by the applicant, no structure form has been retrieved where the permanent magnet and electric excitation involved in the axial hybrid excitation starting generator of the present invention are distributed on concentric circles of the rotor disc, and a cylindrical permanent magnet is embedded in the rotor disc and cooperates with a sector-shaped magnetic yoke. Summary of the Invention

[0008] In order to invent an axial hybrid excitation starting generator, realize the flexible regulation function of the air-gap magnetic field of the starting generator, and make it have the advantages of small volume, high efficiency, and high power density, the present invention adopts the following technical solutions.

[0009] An axial flux hybrid excitation starting generator for a range extender includes a rotor disc, a first stator disc, a second stator disc, a housing assembly, and a power transmission unit; the rotor disc, the first stator disc, and the second stator disc are coaxially arranged and coincide with the central axis of the housing assembly and the power transmission unit. The rotor disc is located between the first stator disc and the second stator disc. The rotor disc, the first stator disc, and the second stator disc are placed inside the housing assembly, and the power transmission unit connects the rotor disc to the range extender engine; The rotor disk includes an excitation coil, an excitation coil bracket, an electro-excitation yoke, a first permanent magnet, a second permanent magnet, a first magnetic conduction ring, a second magnetic conduction ring, a first sector-shaped magnetic yoke, a second sector-shaped magnetic yoke, a first fixed disk, and a second fixed disk; the first fixed disk and the second fixed disk are arranged coaxially and in parallel, the excitation coil bracket is located between the first fixed disk and the second fixed disk, the axis of the excitation coil bracket is parallel to the axis of the first fixed disk, the excitation coil brackets are evenly distributed along the circumference of the first fixed disk, the excitation coil is wound around the excitation coil bracket, the electro-excitation yoke passes through the central hole of the excitation coil bracket, and both ends of the electro-excitation yoke are respectively inserted into the axial holes of the first fixed disk and the second fixed disk. The first permanent magnet and the second permanent magnet are respectively embedded into the axial holes evenly distributed along the circumference of the first fixed disk and the second fixed disk. The first magnetic conduction ring is closely attached to the inner surface of the first fixed disk and is simultaneously in contact with one magnetic pole of the first permanent magnet. The second magnetic conduction ring is closely attached to the inner surface of the second fixed disk and is simultaneously in contact with one magnetic pole of the second permanent magnet. The first sector-shaped magnetic yoke and the second sector-shaped magnetic yoke are respectively embedded into the sector-shaped grooves on the outer surfaces of the first fixed disk and the second fixed disk. The inner surface of the first sector-shaped magnetic yoke is in contact with the other magnetic pole of the first permanent magnet and is simultaneously in contact with one end face of the electro-excitation yoke. The inner surface of the second sector-shaped magnetic yoke is in contact with the other magnetic pole of the second permanent magnet and is simultaneously in contact with the other end face of the electro-excitation yoke; The first stator disk is composed of a first armature winding and a first stator core. The first armature winding is wound into a sector shape and embedded into the stator slots of the first stator core; there is a first air gap between the first stator disk and the rotor disk; The second stator disk is composed of a second armature winding and a second stator core. The second armature winding is wound into a sector shape and embedded into the stator slots of the second stator core. There is a second air gap between the second stator disk and the rotor disk; The housing assembly includes a front end cover and a rear end cover. The front end cover and the rear end cover are coaxial. The front end cover is fixed to the first stator disk, the rear end cover is fixed to the second stator disk, and the front end cover and the rear end cover are buckled together; The power transmission unit includes a rotating shaft and a gear. The rotating shaft passes through the central hole of the rotor disk and is fixed together with the rotor disk. There are bearings between the rotating shaft and the first stator disk and the second stator disk to achieve relative movement.

[0010] Further, the number of the excitation coils is N, N is an even number, and the number of turns of each excitation coil is the same. The winding directions of adjacent excitation coils are opposite, and all the excitation coils are connected in series to form a loop.

[0011] Further, the electro-excitation yoke, the first magnetic conduction ring, the second magnetic conduction ring, the first sector-shaped magnetic yoke, and the second sector-shaped magnetic yoke are all made of magnetic conduction materials.

[0012] Further, both the first permanent magnet and the second permanent magnet are cylindrical, axially magnetized. The magnetization directions of adjacent first permanent magnets are opposite, and the magnetization directions of adjacent second permanent magnets are also opposite. The first permanent magnets and the second permanent magnets are evenly distributed on the first fixing disk and the second fixing disk. The magnetization directions of the first permanent magnet and the second permanent magnet at the same normal position are opposite. The number of permanent magnets is equal to the number of exciting coils, and their positions are in the same normal direction of the first fixing disk and the second fixing disk.

[0013] Further, the first fixing disk and the second fixing disk have exactly the same shape and are both made of non-magnetic materials to prevent magnetic leakage of permanent magnets and electric excitation.

[0014] Further, the number of slots of the first stator core and the second stator core is equal, their shapes are the same, and they are evenly distributed along the circumference. The number of slots is 3*N, and the positions of the slots on the first stator core and the slots on the second stator core are on the same normal line.

[0015] Further, the first permanent magnet, the second permanent magnet, and the electric excitation yoke are distributed on the concentric circles of the first fixing disk and the second fixing disk.

[0016] Further, both the first armature winding and the second armature winding adopt a three-phase distributed winding and are star-connected. The leading ends of the corresponding phases are connected together as the output end.

[0017] Both the front end cover and the rear end cover are made of aluminum material to reduce weight and improve the heat dissipation rate.

[0018] Further, the first stator core and the second stator core are respectively fixed to the front end cover and the rear end cover to keep the first stator core and the second stator core fixed.

[0019] Further, both the first stator core and the second stator core are made of silicon steel soft magnetic material and are formed by a rolling process.

[0020] The working principles of the axial-flux hybrid-excitation starting generator for the range extender in the starting state and the generating state are as follows: When the starting generator is in the starting state, no exciting current is applied to the electro-exciting coil, and alternating currents with opposite directions are applied to the first armature winding and the second armature winding. A rotating magnetic field is generated in the first air gap between the first stator disk and the rotor disk and the second air gap between the second stator disk and the rotor disk. The directions of the rotating magnetic fields are the same. Only the permanent magnet magnetic flux exists in the magnetic circuit. The magnetic circuit of the permanent magnet magnetic flux is: N pole of the first permanent magnet → first sector yoke → first air gap → first stator core → first air gap → adjacent first sector yoke → S pole of the adjacent first permanent magnet → N pole of the adjacent first permanent magnet → first magnetic conduction ring → S pole of the first permanent magnet; N pole of the second permanent magnet → second sector magnetic conduction yoke → second air gap → second stator core → second air gap → adjacent second sector yoke → S pole of the adjacent second permanent magnet → N pole of the adjacent second permanent magnet → second magnetic conduction ring → S pole of the second permanent magnet. The electro-exciting magnetic flux generated by the first armature winding is opposite to the permanent magnet magnetic flux generated by the first permanent magnet in the first air gap, and the electro-exciting magnetic flux generated by the second armature winding is opposite to the permanent magnet magnetic flux generated by the second permanent magnet in the second air gap. The first permanent magnet and the second permanent magnet on the rotor disk generate torque under the action of the rotating magnetic field, causing the rotor disk to rotate synchronously with the rotating magnetic fields of the first stator disk and the second stator disk. The rotor disk drives the rotating shaft to rotate, and the rotating shaft drives the engine flywheel to rotate through gear meshing, thereby starting the range extender engine; When the starting generator is in the power generation state, the range extender engine runs, the flywheel meshing gear belt drives the rotating shaft to rotate, thereby driving the rotor disc to rotate. The permanent magnetic flux generated by the first permanent magnet and the second permanent magnet remains constant, and induced electromotive forces are generated in the first armature winding and the second armature winding. On the premise of keeping the power battery charged, according to the change of the load of the electric vehicle, the value of the exciting current in the exciting coil is adjusted, so that the magnitude of the electro-exciting magnetic field changes, resulting in the change of the magnitude of the combined magnetic field of the permanent magnet and the electro-exciting magnetic field in the first air gap and the second air gap, realizing stable output voltage regulation to meet the power demand. When the load power is small, the electric energy generated only by the permanent magnetic field produced by the permanent magnet can meet the requirements. At this time, the exciting coil of the electro-excitation is not energized, and only the permanent magnetic flux generated by the first permanent magnet and the second permanent magnet exists in the magnetic circuit. The magnetic circuit of the permanent magnetic flux generated by the first permanent magnet is: N pole of the first permanent magnet → first sector yoke → first air gap → first stator core → first air gap → adjacent first sector yoke → S pole of adjacent first permanent magnet → N pole of adjacent first permanent magnet → first magnetic conduction ring → S pole of the first permanent magnet; the magnetic circuit of the permanent magnetic flux generated by the second permanent magnet is: N pole of the second permanent magnet → second sector magnetic conduction yoke → second air gap → second stator core → second air gap → adjacent second sector magnetic conduction yoke → S pole of adjacent second permanent magnet → N pole of adjacent second permanent magnet → second magnetic conduction ring → S pole of the second permanent magnet, and the magnetomotive forces generated by adjacent permanent magnets are connected in series; when the power demand increases, the output voltage of the starting generator drops, and an exciting current is passed through the exciting coil. The magnetic flux direction generated by the exciting current is the same as the magnetic flux direction generated by the first permanent magnet in the first air gap and the same as the magnetic flux direction generated by the second permanent magnet in the second air gap. The exciting magnetic flux is composed of two parts: the permanent magnetic flux and the electro-exciting magnetic flux; the permanent magnetic flux generated by the first permanent magnet and the permanent magnetic flux generated by the second permanent magnet are the same as those when only permanent magnet excitation is used; the magnetic circuit of the electro-exciting magnetic flux is: N pole of the electro-exciting magnetic yoke → first sector yoke → first air gap → first stator core → first air gap → first sector yoke → S pole of the electro-exciting magnetic yoke → N pole of the electro-exciting magnetic yoke → second sector yoke → second air gap → second stator core → second air gap → second sector yoke → S pole of the electro-exciting magnetic yoke. The directions of the electro-exciting magnetic field and the permanent magnetic field passing through the first air gap and the second air gap are the same, and the generated combined magnetic flux is enhanced, so that the final combined air gap magnetic flux increases, and the output voltages generated by the first armature winding and the second armature winding increase to meet the power demand.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0022] An axial hybrid-excitation starting generator proposed by the present invention integrates the starting and power generation functions. Compared with the traditional starting and power generation system that uses a starter and an engine to achieve the starting and power generation functions, the number of motors is reduced, the integration degree is higher, and at the same time, the size of the range extender is reduced and the cost is lowered.

[0023] The present invention combines the advantages of permanent magnet motors and electrically excited motors. By adding an electrically excited coil in the rotor disc, the air-gap magnetic field of the motor can be conveniently adjusted by controlling the current of the excitation coil, while retaining the advantage of high power density of the permanent magnet motor and realizing adjustable magnetic field at the same time.

[0024] The present invention combines an axial flux motor and a hybrid excitation motor, greatly reducing the axial dimension of the motor, and is more suitable for the occasions where the axial dimension requirement of the range extender for range-extended electric vehicles is high. Brief Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic diagram of the overall structure of an axial hybrid excitation starting generator.

[0027] Figure 2 It is a schematic diagram of the internal structure of an axial hybrid excitation starting generator.

[0028] Figure 3 It is a schematic diagram of the structure of the rotor disc in the present invention.

[0029] Figure 4 It is a schematic diagram of the structure of the first stator disc in the present invention.

[0030] Figure 5 It is a schematic diagram of the structure of the second stator disc in the present invention.

[0031] Figure 6 It is a permanent magnet magnetic circuit diagram of the present invention.

[0032] Figure 7 It is an electrically excited magnetic circuit diagram of the present invention

[0033] Figure 8 It is a schematic diagram of the field regulation principle of the hybrid excitation starting generator of the present invention.

[0034] Figure 9 [[ID=4)]]It is the terminal voltage curve under different excitation currents of the present invention.

[0035] Figure 10 It is the starting torque curve of the present invention when only permanent magnet excitation is used.

[0036] In the drawings, the list of components represented by each reference numeral is as follows: 1. Rotor disc, 2. First stator disc, 3. Second stator disc, 4. Housing assembly, 5. Power transmission unit; 101. Second sector magnetic yoke, 102. Second permanent magnet, 103. Second fixed disk, 104. Second magnetic conductive ring, 105. Excitation coil, 106. Electrically excited magnetic yoke, 107. First magnetic conductive ring, 108. First permanent magnet, 109. First fixed disk, 110. First sector magnetic yoke, 111. Excitation coil bracket; 201. First stator core, 202. First armature winding; 301. Second stator core, 302. Second armature winding; 401. Front end cover, 402. Rear end cover; 501. Gear, 502. Rotating shaft. Specific embodiments

[0037] The present invention will be further described in detail below with reference to the accompanying drawings.

[0038] Please refer to Figure 1 As shown, an axial flux hybrid excitation starting generator for a range extender according to this embodiment includes a rotor disk (1), a first stator disk (2), a second stator disk (3), a housing assembly (4), and a power transmission unit (5); the rotor disk (1), the first stator disk (2), and the second stator disk are coaxially arranged (3), coinciding with the central axis of the housing assembly (4) and the power transmission unit (5). The rotor disk (1) is located between the first stator disk (2) and the second stator disk (3). The rotor disk (1), the first stator disk (2), and the second stator disk (3) are placed inside the housing assembly (4), and the power transmission unit (5) connects the rotor disk (1) to the range extender engine.

[0039] Please refer to Figure 1 , Figure 2 and Figure 3As shown, the rotor disk (1) includes an exciting coil (105), an exciting coil bracket (111), an electro-exciting yoke (106), a first permanent magnet (108), a second permanent magnet (102), a first magnetic conduction ring (107), a second magnetic conduction ring (104), a first sector-shaped magnetic yoke (110), a second sector-shaped magnetic yoke (101), a first fixing disk (109), and a second fixing disk (103); the first fixing disk (109) and the second fixing disk (103) are arranged coaxially and in parallel. The exciting coil bracket (111) is located between the first fixing disk (109) and the second fixing disk (103). The axis of the exciting coil bracket (111) is parallel to the axis of the first fixing disk (109). The exciting coil brackets (111) are evenly distributed along the circumference of the first fixing disk (109). The exciting coil (105) is wound around the exciting coil bracket (111). The electro-exciting yoke (106) passes through the central hole of the exciting coil bracket (111). The two ends of the electro-exciting yoke (106) are respectively inserted into the axial holes of the first fixing disk (109) and the second fixing disk (103). The first permanent magnet (108) and the second permanent magnet (102) are respectively embedded into the axial holes evenly distributed along the circumference of the first fixing disk (109) and the second fixing disk (103). The first magnetic conduction ring (107) is closely attached to the inner surface of the first fixing disk (109) and is in contact with one magnetic pole of the first permanent magnet (108) at the same time. The second magnetic conduction ring (104) is closely attached to the inner surface of the second fixing disk (103) and is in contact with one magnetic pole of the second permanent magnet (102) at the same time. The first sector-shaped magnetic yoke (110) and the second sector-shaped magnetic yoke (101) are respectively embedded into the sector-shaped grooves on the outer surfaces of the first fixing disk (109) and the second fixing disk (103). The inner surface of the first sector-shaped magnetic yoke (110) is in contact with the other magnetic pole of the first permanent magnet and is in contact with one end face of the electro-exciting yoke (106) at the same time. The inner surface of the second sector-shaped magnetic yoke (101) is in contact with the other magnetic pole of the second permanent magnet (102) and is in contact with the other end face of the electro-exciting yoke (106) at the same time.

[0040] Please refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, the first stator disk (2) is composed of a first armature winding (202) and a first stator core (201). The first armature winding (202) is wound into a sector shape and embedded into the stator slots of the first stator core (201); there is a first air gap between the first stator disk (2) and the rotor disk (1).

[0041] Please refer to Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the second stator disk (3) is composed of a second armature winding (302) and a second stator core (301). The second armature winding (302) is wound into a sector shape and embedded in the stator slots of the second stator core (301). There is a second air gap between the second stator disk (3) and the rotor disk (1).

[0042] Please refer to Figure 1 and Figure 2 As shown, the housing assembly (4) includes a front end cover (401) and a rear end cover (402). The front end cover (401) and the rear end cover (402) are coaxial. The front end cover (401) is fixed to the first stator disk, and the rear end cover (402) is fixed to the second stator disk (402). The front end cover (401) and the rear end cover (402) are buckled together.

[0043] Please refer to Figure 1 and Figure 2 As shown, the power transmission unit (5) includes a rotating shaft (502) and a gear (501). The rotating shaft (502) passes through the central hole of the rotor disk (1) and is fixed to the rotor disk (1). There are bearings between the rotating shaft (502) and the first stator disk (2) and the second stator disk (3) to achieve relative movement.

[0044] Among them, the number of the exciting coils (105) is 12, and the number of turns of each exciting coil (105) is the same. The winding directions of adjacent exciting coils (105) are opposite, and all the exciting coils (105) are connected in series to form a circuit.

[0045] Among them, the electro-magnetic yoke (106), the first magnetic conducting ring (107), the second magnetic conducting ring (104), the first sector-shaped magnetic conducting yoke (110), and the second sector-shaped magnetic conducting yoke (101) are all made of ferromagnetic magnetic conducting materials.

[0046] Please refer to Figure 3 As shown, the first permanent magnet (108) and the second permanent magnet (102) are both cylindrical and axially magnetized. The magnetization directions of adjacent first permanent magnets (108) are opposite, and the magnetization directions of adjacent second permanent magnets (102) are also opposite. The first permanent magnets (108) and the second permanent magnets (102) are evenly distributed on the first fixing disk (109) and the second fixing disk (103) respectively. The magnetization directions of the first permanent magnet (108) and the second permanent magnet (102) at the same normal position are opposite. The number of the first permanent magnets (108) and the second permanent magnets (102) is equal to the number of the exciting coils (105), and their positions are in the same normal direction of the first fixing disk (109) and the second fixing disk (103).

[0047] Among them, the first fixing disk (109) and the second fixing disk (103) have exactly the same shape and are both made of copper non-magnetic conducting materials to prevent magnetic leakage between the permanent magnet and the electro-magnetic excitation.

[0048] Among them, the number of slots of the first stator core (201) and the second stator core (301) is equal, the shapes are the same, and they are evenly distributed along the circumference. The number of slots is 36 for both. The positions of the slots on the first stator core (201) and the slots on the second stator core (301) are on the same normal line.

[0049] Among them, the first permanent magnet (108), the second permanent magnet (102), and the electro-excited yoke (106) are distributed on the concentric circles of the first fixing disk (109).

[0050] Among them, both the first armature winding (202) and the second armature winding (203) adopt a three-phase distributed winding and are star-connected. The leading ends of the corresponding phases are connected together as the output terminals.

[0051] Among them, both the front end cover (401) and the rear end cover (402) are made of aluminum material to reduce weight and improve the heat dissipation rate.

[0052] Among them, the first stator core (201) and the second stator core (202) are respectively fixed to the front end cover (401) and the rear end cover (402) to keep the first stator core (201) and the second stator core (202) fixed.

[0051] Among them, both the first stator core (201) and the second stator core (202) are made of silicon steel soft magnetic material by a rolling process.

[0053] Please refer to Figure 6 、 Figure 7 and Figure 8 as shown. The working principles of the starting state and the generating state of the axial-flux hybrid-excitation starting generator for the range extender are as follows: When the starting generator is in the starting state, no exciting current is applied to the electric exciting coil (105), alternating currents with opposite directions are applied to the first armature winding (202) and the second armature winding (302), a rotating magnetic field is generated in the first air gap between the first stator disk (2) and the rotor disk (1) and the second air gap between the second stator disk (3) and the rotor disk (1), the directions of the rotating magnetic fields are the same, and there is only permanent magnetic flux in the magnetic circuit. The magnetic circuit of the permanent magnetic flux is: N pole of the first permanent magnet (108) → first sector yoke (110) → first air gap → first stator iron core (201) → first air gap → adjacent first sector yoke (110) → S pole of the adjacent first permanent magnet (108) → N pole of the adjacent first permanent magnet (108) → first magnetic conduction ring (107) → S pole of the first permanent magnet (108); N pole of the second permanent magnet (102) → second sector magnetic conduction yoke (101) → second air gap → second stator iron core (301) → second air gap → adjacent second sector magnetic conduction yoke (101) → S pole of the adjacent second permanent magnet (102) → N pole of the adjacent second permanent magnet (102) → second magnetic conduction ring (104) → S pole of the second permanent magnet (102). The electric exciting magnetic flux generated by the first armature winding (202) is opposite to the direction of the permanent magnetic flux generated by the first permanent magnet (108) in the first air gap, and the electric exciting magnetic flux generated by the second armature winding (302) is opposite to the direction of the permanent magnetic flux generated by the second permanent magnet (102) in the second air gap. The first permanent magnet (108) and the second permanent magnet (102) on the rotor disk (1) generate torque under the action of the rotating magnetic field, so that the rotor disk (1) rotates synchronously with the rotating magnetic fields of the first stator disk (2) and the second stator disk (3). The rotor disk (1) drives the rotating shaft (502) to rotate, and the rotating shaft (502) drives the engine flywheel to rotate through the gear (501), thereby starting the range extender engine; When the starting generator is in the power generation state, the range extender engine runs, and the flywheel meshing gear (501) drives the through-shaft (502) to rotate, thereby driving the rotor disc (1) to rotate. The permanent magnetic flux generated by the first permanent magnet (108) and the second permanent magnet (102) remains constant, inducing electromotive forces in the first armature winding (202) and the second armature winding (302). On the premise of keeping the power battery charged, according to the change of the load of the electric vehicle, the value of the exciting current in the exciting coil (105) is adjusted, so that the magnitude of the electro-exciting magnetic field changes, resulting in the change of the magnitude of the combined magnetic field of the permanent magnet and the electro-exciting magnetic field in the first air gap and the second air gap, realizing stable output voltage regulation to meet the power demand. When the load power is small, the electric energy generated only by the permanent magnetic field produced by the permanent magnet can meet the requirements. At this time, the exciting coil (105) of the electro-excitation is not energized, and only the permanent magnetic flux generated by the first permanent magnet (108) and the second permanent magnet (102) exists in the magnetic circuit. The magnetic circuit of the permanent magnetic flux generated by the first permanent magnet is: N pole of the first permanent magnet (108) → first sector yoke (110) → first air gap → first stator core (201) → first air gap → adjacent first sector yoke (110) → S pole of the adjacent first permanent magnet (108) → N pole of the adjacent first permanent magnet (108) → first magnetic conduction ring (107) → S pole of the first permanent magnet (108); The magnetic circuit of the permanent magnetic flux generated by the second permanent magnet is: N pole of the second permanent magnet (102) → second sector magnetic conduction yoke (101) → second air gap → second stator core (301) → second air gap → adjacent second sector magnetic conduction yoke (101) → S pole of the adjacent second permanent magnet (102) → N pole of the adjacent second permanent magnet (102) → second magnetic conduction ring (104) → S pole of the second permanent magnet (102), and the magnetomotive forces generated by adjacent permanent magnets are in series; When the power demand increases, the output voltage of the starting generator drops, and an exciting current is passed through the exciting coil (105). The direction of the magnetic flux generated by the exciting current is the same as the direction of the magnetic flux generated by the first permanent magnet (108) in the first air gap and the same as the direction of the magnetic flux generated by the second permanent magnet (102) in the second air gap. The exciting magnetic flux is composed of two parts: permanent magnetic flux and electro-exciting magnetic flux; The permanent magnetic flux generated by the first permanent magnet (108) and the permanent magnetic flux generated by the second permanent magnet (102) are the same as those when only permanent magnet excitation is used; The magnetic circuit of the electro-exciting magnetic flux is: N pole of the electro-exciting yoke (106) → first sector yoke (110) → first air gap → first stator core (201) → first air gap → first sector yoke (110) → S pole of the electro-exciting yoke (106) → N pole of the electro-exciting yoke (106) → second sector yoke (102) → second air gap → second stator core (301) → second air gap → second sector yoke (102) → S pole of the electro-exciting yoke (106).The directions of the electric excitation magnetic field and the permanent magnet magnetic field passing through the first air gap and the second air gap are the same, and the generated resultant magnetic flux is enhanced, so that the final resultant air gap magnetic flux increases, and the output voltages generated by the first armature winding (202) and the second armature winding (302) are increased to meet the power demand.

[0054] Please refer to Figure 9 As shown, when the excitation current gradually increases from 0 A to 2 A, the no-load terminal voltage waveforms of phase A of the first armature winding (202) and the second armature winding (302) are significantly improved. Moreover, when the excitation current is 0 A, the no-load terminal voltage is 68 V and the voltage can still be output. When the excitation current is 2 A, the no-load terminal voltage is 118 V. It can be seen that the present invention fully utilizes the high-power density advantage of the permanent magnet motor and also has the voltage regulation characteristic of the electric excitation motor.

[0055] Please refer to Figure 10 As shown, in the starting state, relying only on permanent magnet excitation, the maximum starting torque reaches 15.1 N·m, and the average torque is 14.2 N·m, which can meet the starting requirement of 14 N·m of the range extender engine. No excitation current is required, greatly reducing the excitation consumption.

[0056] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An axial flux hybrid-excitation starting generator for a range extender, characterized in that: It includes a rotor disc (1), a first stator disc (2), a second stator disc (3), a housing assembly (4), and a power transmission unit (5); the rotor disc (1), the first stator disc (2), and the second stator disc (3) are coaxially arranged and coincide with the central axis of the housing assembly (4) and the power transmission unit (5). The rotor disc (1) is located between the first stator disc (2) and the second stator disc (3). The rotor disc (1), the first stator disc (2), and the second stator disc (3) are placed inside the housing assembly (4), and the power transmission unit (5) connects the rotor disc (1) to the range extender engine; The rotor disc (1) includes an exciting coil (105), an exciting coil bracket (111), an electro-exciting yoke (106), a first permanent magnet (108), a second permanent magnet (102), a first magnetic conduction ring (107), a second magnetic conduction ring (104), a first sector yoke (110), a second sector yoke (101), a first fixing disc (109), and a second fixing disc (103); the first fixing disc (109) and the second fixing disc (103) are arranged coaxially and parallelly. The exciting coil bracket (111) is located between the first fixing disc (109) and the second fixing disc (103). The axis of the exciting coil bracket (111) is parallel to the axis of the first fixing disc (109). The exciting coil brackets (111) are evenly distributed along the circumference of the first fixing disc (109). The exciting coil (105) is wound around the exciting coil bracket (111). The electro-exciting yoke (106) passes through the central hole of the exciting coil bracket (111). The two ends of the electro-exciting yoke (106) are respectively inserted into the axial holes of the first fixing disc (109) and the second fixing disc (103). The first permanent magnet (108) and the second permanent magnet (102) are respectively embedded into the axially distributed holes evenly along the circumference of the first fixing disc (109) and the second fixing disc (103). The first magnetic conduction ring (107) is closely attached to the inner surface of the first fixing disc (109) and is in contact with one magnetic pole of the first permanent magnet (108) at the same time. The second magnetic conduction ring (104) is closely attached to the inner surface of the second fixing disc (103) and is in contact with one magnetic pole of the second permanent magnet (102) at the same time. The first sector yoke (110) and the second sector yoke (101) are respectively embedded into the sector grooves on the outer surfaces of the first fixing disc (109) and the second fixing disc (103). The inner surface of the first sector yoke (110) is in contact with the other magnetic pole of the first permanent magnet and is in contact with one end face of the electro-exciting yoke (106) at the same time. The inner surface of the second sector yoke (101) is in contact with the other magnetic pole of the second permanent magnet (102) and is in contact with the other end face of the electro-exciting yoke (106) at the same time; The first stator disc (2) is composed of a first armature winding (202) and a first stator core (201). The first armature winding (202) is wound into a sector and embedded into the stator slots of the first stator core (201); there is a first air gap between the first stator disc (2) and the rotor disc (1); The second stator disk (3) consists of a second armature winding (302) and a second stator core (301). The second armature winding (302) is wound into a sector shape and embedded in the stator slots of the second stator core (301). A second air gap is provided between the second stator disk (3) and the rotor disk (1). The housing assembly (4) includes a front end cover (401) and a rear end cover (402). The front end cover (401) and the rear end cover (402) are coaxial. The front end cover (401) is fixed to the first stator disk, and the rear end cover (402) is fixed to the second stator disk (402). The front end cover (401) and the rear end cover (402) are buckled together. The power transmission unit (5) includes a rotating shaft (502) and a gear (501). The rotating shaft (502) passes through the central hole of the rotor disk (1) and is fixed to the rotor disk (1). Bearings are provided between the rotating shaft (502) and the first stator disk (2) and the second stator disk (3) to achieve relative movement.

2. The axial-flux hybrid-excitation starting generator for a range extender according to claim 1, wherein: The number of the exciting coils (105) is N, where N is an even number, and the number of turns of each exciting coil (105) is the same. The winding directions of adjacent exciting coils (105) are opposite, and all the exciting coils (105) are connected in series to form a loop.

3. An axial-flux hybrid-excitation starting generator for a range extender, characterized in that: The electric excitation yoke (106), the first magnetic conduction ring (107), the second magnetic conduction ring (104), the first sector magnetic conduction yoke (110) and the second sector magnetic conduction yoke (1101) are all made of magnetic conduction materials.

4. An axial flux hybrid excitation starting generator for a range extender, characterized in that: The first permanent magnet (108) and the second permanent magnet (102) are both cylindrical and axially magnetized. The magnetization directions of adjacent first permanent magnets (108) are opposite, and the magnetization directions of adjacent second permanent magnets (102) are also opposite. The first permanent magnets (108) and the second permanent magnets (102) are evenly distributed on the first fixing disk (109) and the second fixing disk (103) respectively. The magnetization directions of the first permanent magnet (108) and the second permanent magnet (102) at the same normal position are opposite. The numbers of the first permanent magnets (108), the second permanent magnets (102) and the exciting coils (105) are equal, and their positions are in the same normal direction of the first fixing disk (109) and the second fixing disk (103).

5. An axial-flux hybrid-excitation starting generator for a range extender, characterized in that: The first fixing disk (109) and the second fixing disk (103) have exactly the same shape and are both made of non-magnetic materials to prevent magnetic leakage of permanent magnetism and electric excitation.

6. The axial-flux hybrid-excitation starting generator for a range extender according to claim 1, characterized in that: The number of slots of the first stator core (201) and the second stator core (301) is equal, the shapes are the same, and they are evenly distributed along the circumference. The number of slots is 3*N. The positions of the slots on the first stator core (201) and the slots on the second stator core (301) are on the same normal line.

7. An axial-flux hybrid-excitation starting generator for a range extender, characterized in that: The first permanent magnets (108), the second permanent magnets (102) and the electric excitation yoke (106) are distributed on the concentric circles of the first fixing disk (109) and the second fixing disk (103).

8. An axial-flux hybrid-excitation starting generator for a range extender, characterized in that: The working principles of the starting state and the generating state of the axial-flux hybrid-excitation starting generator for the range extender are as follows: When the starting generator is in the starting state, no exciting current is passed through the electric exciting coil (105), alternating currents with opposite directions are passed through the first armature winding (202) and the second armature winding (302), a rotating magnetic field is generated in the first air gap between the first stator disk (2) and the rotor disk (1) and the second air gap between the second stator disk (3) and the rotor disk (1), the directions of the rotating magnetic fields are the same, and there is only permanent magnetic flux in the magnetic circuit. The magnetic circuit of the permanent magnetic flux is: N pole of the first permanent magnet (108) → first sector yoke (110) → first air gap → first stator iron core (201) → first air gap → adjacent first sector yoke (110) → S pole of adjacent first permanent magnet (108) → N pole of adjacent first permanent magnet (108) → first magnetic conduction ring (107) → S pole of first permanent magnet (108); N pole of the second permanent magnet (102) → second sector magnetic conduction yoke (101) → second air gap → second stator iron core (301) → second air gap → adjacent second sector magnetic conduction yoke (101) → S pole of adjacent second permanent magnet (102) → N pole of adjacent second permanent magnet (102) → second magnetic conduction ring (104) → S pole of second permanent magnet (102). The electric exciting magnetic flux generated by the first armature winding (202) is opposite to the direction of the permanent magnetic flux generated by the first permanent magnet (108) in the first air gap, and the electric exciting magnetic flux generated by the second armature winding (302) is opposite to the direction of the permanent magnetic flux generated by the second permanent magnet (102) in the second air gap. The first permanent magnet (108) and the second permanent magnet (102) on the rotor disk (1) generate torque under the action of the rotating magnetic field, causing the rotor disk (1) to rotate synchronously with the rotating magnetic fields of the first stator disk (2) and the second stator disk (3). The rotor disk (1) drives the rotating shaft (502) to rotate, and the rotating shaft (502) drives the engine flywheel to rotate through the gear (501), thereby starting the range extender engine; When the starting generator is in the power generation state, the range extender engine runs, and the flywheel meshing gear (501) drives the through-shaft (502) to rotate, thereby driving the rotor disk (1) to rotate. The permanent magnetic flux generated by the first permanent magnet (108) and the second permanent magnet (102) remains constant, inducing electromotive forces in the first armature winding (202) and the second armature winding (302). On the premise of maintaining the charging of the power battery, according to the change of the load of the electric vehicle, the value of the exciting current in the exciting coil (105) is adjusted, so that the magnitude of the electro-exciting magnetic field changes, resulting in the change of the magnitude of the combined magnetic field of the permanent magnet and the electro-excitation in the first air gap and the second air gap, realizing stable output voltage regulation to meet the power demand. When the load power is small, the electric energy generated by only the permanent magnetic field produced by the permanent magnet can meet the requirements. At this time, the exciting coil (105) of the electro-excitation is not energized, and only the permanent magnetic flux generated by the first permanent magnet (108) and the second permanent magnet (102) exists in the magnetic circuit. The magnetic circuit of the permanent magnetic flux generated by the first permanent magnet is: N pole of the first permanent magnet (108) → first sector yoke (110) → first air gap → first stator core (201) → first air gap → adjacent first sector yoke (110) → S pole of the adjacent first permanent magnet (108) → N pole of the adjacent first permanent magnet (108) → first magnetic conduction ring (107) → S pole of the first permanent magnet (108); The magnetic circuit of the permanent magnetic flux generated by the second permanent magnet is: N pole of the second permanent magnet (102) → second sector magnetic conduction yoke (101) → second air gap → second stator core (301) → second air gap → adjacent second sector magnetic conduction yoke (101) → S pole of the adjacent second permanent magnet (102) → N pole of the adjacent second permanent magnet (102) → second magnetic conduction ring (104) → S pole of the second permanent magnet (102), and the magnetomotive forces generated by adjacent permanent magnets are in series; When the power demand increases, the output voltage of the starting generator drops, and an exciting current is passed through the exciting coil (105). The direction of the magnetic flux generated by the exciting current is the same as the direction of the magnetic flux generated by the first permanent magnet (108) in the first air gap and the same as the direction of the magnetic flux generated by the second permanent magnet (102) in the second air gap. The exciting magnetic flux is composed of two parts: permanent magnetic flux and electro-exciting magnetic flux; The permanent magnetic flux generated by the first permanent magnet (108) and the permanent magnetic flux generated by the second permanent magnet (102) are the same as those when only permanent magnet excitation is used; The magnetic circuit of the electro-exciting magnetic flux is: N pole of the electro-exciting yoke (106) → first sector yoke (110) → first air gap → first stator core (201) → first air gap → first sector yoke (110) → S pole of the electro-exciting yoke (106) → N pole of the electro-exciting yoke (106) → second sector yoke (102) → second air gap → second stator core (301) → second air gap → second sector yoke (102) → S pole of the electro-exciting yoke (106).The directions of the electro-excited magnetic field and the permanent magnetic field passing through the first air gap and the second air gap are the same, and the generated resultant magnetic flux is enhanced, so that the final resultant air-gap magnetic flux increases, and the output voltages generated by the first armature winding (202) and the second armature winding (302) increase to meet the power requirement.

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