Rotor assembly, permanent magnet synchronous motor, traction system and vehicle

Abstract

The embodiment of the invention provides a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The rotor assembly comprises a rotor iron core which is provided with a plurality of permanent magnet grooves which are uniformly distributed along the circumferential direction; the permanent magnets are arranged in the permanent magnet grooves; the plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet grooves, and each magnetic conductive block is arranged on one side, close to the rotating shaft, of the corresponding permanent magnet groove along the radial direction; the magnetic conductive block is configured to move between a first position close to the permanent magnet groove and a second position far away from the permanent magnet groove so as to adjust the magnetic field distribution of the rotor assembly.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and more specifically, to a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. Background Art

[0002] With the rapid development of power electronics technology and high-performance rare earth materials, permanent magnet synchronous motors have been widely used due to their high power density and high efficiency. The rotor of a permanent magnet synchronous motor is excited by rare earth permanent magnets. Since the excitation magnetic field cannot be adjusted and is limited by the DC bus voltage and inverter capacity, when the system exceeds the rated power, as the speed increases, the back electromotive force of the stator winding increases. To ensure its efficient operation, the rotor needs to be weakly magnetically controlled (also known as magnetic modulation). The magnetic modulation methods in related technologies include AC pulse magnetic modulation, DC pulse magnetic modulation, and mechanical magnetic modulation.

[0003] The AC pulse magnetic modulation method is to apply a direct-axis charging / demagnetizing pulse current to the stator armature winding to realize the magnetization / demagnetization of the permanent magnet, thereby achieving the purpose of adjusting the air gap magnetic density and widening the operation of the motor.

[0004] The DC pulse magnetic modulation method is to set an additional DC magnetic modulation winding dedicated to magnetic modulation on the stator or rotor of the motor to realize the charging / demagnetization of the permanent magnet. It can also be realized by directly applying magnetic modulation current to the armature winding of the motor.

[0005] Mechanical magnetic adjustment can be achieved by setting multiple slots in the rotor core and setting permanent magnets with the same polarity at both ends of the slots. When the motor speed increases, the permanent magnets that are not fixed will move closer to the air gap under the action of centrifugal force, so that the magnetic resistance of the main pole leakage magnetic circuit is reduced, the leakage magnetic flux is increased, and the magnetic flux passing through the air gap is reduced, so as to achieve the purpose of reducing the air gap magnetic density when the motor is running at high speed.

[0006] Among the above methods, the weakening magnetic current during DC or AC pulse magnetic modulation will lead to higher copper loss, which will reduce the high-speed operation efficiency of the permanent magnet synchronous motor; at the same time, this method also requires the addition of additional components in the circuit part, resulting in increased costs. The existing mechanical magnetic modulation methods are mostly passive adjustments, that is, they cannot actively control their weak magnetic ability; and the weak magnetic ability of this method is limited and cannot achieve the expected effect. Summary of the invention

[0007] The present application mainly provides a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. Various aspects involved in the embodiments of the present application are introduced below.

[0008] In a first aspect, a rotor assembly is provided, comprising: a rotor core having a plurality of permanent magnet slots evenly distributed along the circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being radially arranged on a side of the corresponding permanent magnet slot close to the rotating shaft; the magnetic conductive blocks being configured to move between a first position close to the permanent magnet slots and a second position away from the permanent magnet slots to adjust the magnetic field distribution of the rotor assembly.

[0009] According to the above technical means, by setting a magnetic conductive block corresponding to multiple groups of permanent magnets in the rotor assembly, the position of the magnetic conductive block is adjusted to generate different leakage magnetic fields, thereby achieving the adjustment of the permanent magnetic field, ensuring that the permanent magnet synchronous motor has a wider speed adjustment range, improving the power factor of the permanent magnet motor at high speed, and being able to eliminate or reduce the motor iron loss. When the magnetic conductive block moves to one end close to the permanent magnet, the rotor permanent magnetic field can be gathered in the rotor assembly, which can avoid the motor from generating a large back electromotive force in the slot body when it is reversely dragged, and ensure the safety of the traction system when the stator winding turns are short-circuited.

[0010] In some embodiments, when the magnetic conductive block is located at the first position, one end of the magnetic conductive block close to the permanent magnet slot along the radial direction abuts against the rotor core.

[0011] According to the above technical means, the end face of the magnetic block completely overlaps with the side wall of the rotor core, and there is no gap between the magnetic block and the rotor core; the increase in magnetic resistance caused by the gap can be avoided, ensuring that the permanent magnetic field of the permanent magnet can be more concentrated in the magnetic block.

[0012] In some embodiments, the permanent magnet slot includes a first permanent magnet slot and a second permanent magnet slot symmetrically arranged about the center line of the D axis; the first permanent magnet slot forms a first opening near one end of the rotating shaft and the second permanent magnet slot forms a first opening near one end of the rotating shaft, and the width of the magnetic conductive block along the radial direction perpendicular to the radial direction is not less than the width of the first opening, so that when the magnetic conductive block is located at the first position, the end surface of the magnetic conductive block near one end of the permanent magnet slot can cover the first opening.

[0013] According to the above technical means, when the magnetic conductive block is located at the first position, the material with higher magnetic permeability accounts for a larger proportion in the iron core, which is more conducive to guiding the magnetic field into the magnetic conductive block.

[0014] In some embodiments, the rotor core has a recessed portion that is recessed in a direction close to the permanent magnet slot, the recessed portion is arranged corresponding to the permanent magnet slot, and is located on a side of the permanent magnet slot close to the rotating shaft; the magnetic conductive block has a protrusion at one end close to the permanent magnet slot, the protrusion matches the shape of the recessed portion, and when the magnetic conductive block is located at the first position, the protrusion extends into the recessed portion.

[0015] According to the above technical means, by providing a protrusion extending in the direction of the permanent magnet slot on the magnetic block, when the magnetic block moves to the first position, the permanent magnetic field of the permanent magnet can be more quickly gathered in the magnetic block with smaller magnetic resistance, thereby avoiding the iron core part reaching the saturation state first.

[0016] In some embodiments, the protrusion is an arc-shaped end surface.

[0017] In some embodiments, the protrusion includes a first end face and a second end face arranged in a V-shape, and an angle formed by the first end face and the second end face is oriented toward an end close to the permanent magnet slot.

[0018] According to the above technical means, the protrusion is set to be V-shaped, which has a simple structure and is easy to process.

[0019] In some embodiments, the angle formed by the first end surface and the second end surface is an obtuse angle.

[0020] According to the above technical means, the angle between the first end face and the second end face is set to an obtuse angle, so that the distance that the first end of the magnetic block extends outward in the direction close to the permanent magnet slot will not be too long, thereby avoiding the problem that when the magnetic block is in the second position, the air gap between the magnetic block and the permanent magnet slot will form a magnetic barrier, affecting the distribution of the permanent magnetic field of the rotor assembly, causing the efficiency of the motor to decrease, and other problems.

[0021] In some embodiments, the rotor core has a plurality of slide grooves corresponding to a plurality of permanent magnet slots, each of the slide grooves is arranged radially, the first end of the slide groove along the radial direction is close to the permanent magnet slot, and the second end is spaced apart from the rotating shaft of the rotor assembly, and the magnetic conductive block can slide in the slide groove to move between the first position and the second position; the first end of the slide groove has a recessed area, and the recessed area matches the shape of the protrusion.

[0022] In some embodiments, an arc angle of the first permanent magnet slot and the second permanent magnet slot close to one end of the rotating shaft is less than or equal to an arc angle of the first permanent magnet slot and the second permanent magnet slot away from one end of the rotating shaft.

[0023] According to the above technical means, the rotor structure with V-shaped permanent magnet slots has the advantages of small leakage coefficient, no need for magnetic isolation measures on the rotating shaft, easier to control pole arc coefficient, high mechanical strength of rotor punchings, and not easy deformation of the rotor after installation. It can be used in many fields such as rail transportation and electric vehicles.

[0024] In some embodiments, the first position is located near the first permanent magnet slot and the second permanent magnet slot and close to one end of the rotating shaft.

[0025] According to the above technical means, setting the first position close to the closing end of the V-shaped permanent magnet slot can achieve the effect of deeply adjusting the magnetic field without increasing the rotational inertia of the rotor too much, and can maintain a high mechanical strength.

[0026] In some embodiments, a first magnetic isolation groove and a second magnetic isolation groove are disposed at both ends of the first permanent magnet groove, and a third magnetic isolation groove and a fourth magnetic isolation groove are disposed at both ends of the second permanent magnet groove.

[0027] According to the above technical means, the above-mentioned multiple magnetic isolation grooves can prevent the two magnetic poles of the permanent magnets arranged in the permanent magnet grooves from directly contacting the rotor core.

[0028] In some embodiments, the rotor core also has an internal magnetic bridge arranged corresponding to the permanent magnet slot, and the internal magnetic bridge includes a first internal magnetic bridge and a second internal magnetic bridge. The first internal magnetic bridge is located between the slide slot and the second magnetic isolation slot, and the second internal magnetic bridge is located between the slide slot and the fourth magnetic isolation slot.

[0029] According to the above technical means, the first internal magnetic bridge and the second internal magnetic bridge can optimize the distribution of the permanent magnetic field of the rotor.

[0030] In some embodiments, the rotor core also has an external magnetic bridge arranged corresponding to the permanent magnet slot, and the external magnetic bridge includes a first external magnetic bridge and a second external magnetic bridge. The first external magnetic bridge is located between the first magnetic isolation slot and the outer edge of the rotor assembly, and the second external magnetic bridge is located between the third magnetic isolation slot and the outer edge of the rotor assembly.

[0031] According to the above technical means, the first outer magnetic bridge and the second outer magnetic bridge can increase the structural strength of the rotor core.

[0032] In some embodiments, the first magnetic isolation groove and the third magnetic isolation groove penetrate the rotor core in a radial direction.

[0033] According to the above technical means, setting the first magnetic isolation groove and the third magnetic isolation groove to penetrate the rotor core in the radial direction can reduce the magnetic leakage of the rotor permanent magnet and eliminate the adverse effect of the magnetic bridge on the magnetic field distribution.

[0034] In some embodiments, the rotor assembly further includes a rotor sleeve, which is sleeved on the outer side of the rotor core.

[0035] According to the above technical means, a rotor sleeve is provided on the outside of the rotor core, which can improve the strength of the rotor assembly.

[0036] In some embodiments, the rotor sleeve is made of carbon fiber or non-magnetic alloy material.

[0037] According to the above technical means, the rotor sleeve is made of carbon fiber or non-magnetic and magnetically conductive alloy material, which can meet the strength requirements and will not affect the magnetic field distribution of the rotor assembly.

[0038] In some embodiments, it is characterized in that the rotor assembly also includes a driving mechanism for driving the magnetic conductive block to move.

[0039] In some embodiments, the rotor core includes a core shaft core, a D-axis core and a Q-axis core; wherein the core shaft core is a sleeve close to the axis of the rotor core; the D-axis core is located between the first permanent magnet slot and the second permanent magnet slot; and the Q-axis core is located between two adjacent permanent magnet slots.

[0040] In some embodiments, the core shaft core, the D-axis core and the Q-axis core are integrally formed.

[0041] According to the above technical means, the one-piece molding method is simple in process and can reduce the processing cost of the rotor core.

[0042] In some embodiments, the core shaft core, the D-axis core and the Q-axis core are a combined structure; the D-axis core is made of silicon steel material, amorphous material or nanocrystalline material; the Q-axis core is made of silicon steel material, amorphous material or nanocrystalline material.

[0043] According to the above technical means, the D-axis iron core is made of silicon steel material, amorphous material or nanocrystalline material, which has a small iron loss and can reduce the heat of the rotor core. The Q-axis iron core is made of silicon steel material, amorphous material or nanocrystalline material. The orientation direction of the silicon steel material is axial and has a high magnetic permeability. The nanocrystalline material also has a high magnetic permeability, which can reduce the heat of the rotor assembly while achieving miniaturization and lightweight of the motor.

[0044] In some embodiments, the core shaft core and the Q-axis core are integrally formed, or the Q-axis core and the core shaft core are connected via a dovetail structure.

[0045] According to the above technical means, the core shaft core and the Q-axis core are integrally formed, and can be made of the same material, which can reduce the processing steps. The Q-axis core and the core shaft core are connected by a dovetail structure, which can greatly improve the utilization rate of materials and save manufacturing costs.

[0046] In the second aspect, a permanent magnet synchronous motor is provided, comprising a rotor assembly and a stator assembly, wherein the rotor assembly is the rotor assembly described in the first aspect. In the third aspect, a permanent magnet synchronous motor is provided, which is applied to a power system of an urban rail transit vehicle, wherein the vehicle power system comprises a plurality of permanent magnet synchronous motors for providing power to the vehicle, wherein the permanent magnet synchronous motor comprises a rotor assembly and a stator assembly, wherein the rotor assembly comprises: a rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; a permanent magnet disposed in the permanent magnet slot; a plurality of magnetic conductive blocks disposed corresponding to the plurality of permanent magnet slots, wherein each magnetic conductive block is disposed radially on a side of the corresponding permanent magnet slot close to the rotating shaft; the magnetic conductive blocks are configured as follows: when the vehicle is in an idling condition, the magnetic conductive blocks are located at a first position close to the permanent magnet slots to reduce the iron loss of the permanent magnet synchronous motor in the idling condition; when the vehicle is in a traction condition, the magnetic conductive blocks are located at a second position away from the permanent magnet slots to increase the air gap magnetic field strength between the rotor assembly and the stator assembly.

[0047] In some embodiments, the magnetic block is also configured as follows: when the speed of the vehicle is greater than a first speed threshold, the magnetic block moves between the first position and the second position to adjust the magnetic field distribution of the rotor assembly and increase the speed regulation range of the permanent magnet synchronous motor; wherein the first speed threshold is related to the rated speed of the permanent magnet synchronous motor.

[0048] In a fourth aspect, a power system is provided, which is applied to an urban rail transit vehicle and is used to provide power for the vehicle. The power system includes the permanent magnet synchronous motor as described in the third aspect.

[0049] In a fifth aspect, an urban rail transit vehicle is provided, wherein the vehicle comprises the permanent magnet synchronous motor as described in the third aspect or the power system as described in the fourth aspect.

[0050] In a sixth aspect, a permanent magnet synchronous traction motor is provided, which is applied to the traction system of a locomotive, and is characterized in that the permanent magnet synchronous traction motor includes a rotor assembly and a stator assembly, and the rotor assembly includes: a rotor core, having a plurality of permanent magnet slots evenly distributed along the circumferential direction; permanent magnets, arranged in the permanent magnet slots; a plurality of magnetic conductive blocks, arranged corresponding to the plurality of permanent magnet slots, and each of the magnetic conductive blocks is radially arranged on a side of the corresponding permanent magnet slot close to the rotating shaft; the magnetic conductive blocks are configured to: according to the running speed of the locomotive, move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot, and adjust the magnetic field distribution of the rotor assembly so that the permanent magnet synchronous traction motor outputs constant power when driving the locomotive to operate within its running speed range.

[0051] In some embodiments, the magnetic block is also configured as follows: when the speed of the locomotive is greater than a first speed, the magnetic block is located at or close to the first position to reduce the air gap magnetic field strength of the rotor assembly and increase the speed of the permanent magnet synchronous traction motor, and the first speed is related to the rated speed of the permanent magnet synchronous traction motor.

[0052] In a seventh aspect, a traction system is provided for use in a locomotive, wherein the traction system comprises the permanent magnet synchronous traction motor as described in the sixth aspect.

[0053] In an eighth aspect, a locomotive is provided, comprising the permanent magnet synchronous traction motor as described in the sixth aspect or the traction system as described in the seventh aspect.

[0054] In a ninth aspect, a power system is provided for use in a train, the power system comprising a plurality of permanent magnet synchronous motors for driving the train, each of the permanent magnet synchronous motors comprising a rotor assembly and a stator assembly; the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being radially arranged on a side of the corresponding permanent magnet slot close to the rotating shaft, the magnetic conductive blocks being used to switch between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; the power system is configured to: in the event of a turn-to-turn short circuit fault in a target permanent magnet synchronous motor among the plurality of permanent magnet synchronous motors, switch the magnetic conductive block in the target permanent magnet synchronous motor to the first position to short-circuit the main magnetic flux of the target permanent magnet synchronous motor, so that the target permanent magnet synchronous motor is out of service.

[0055] In a tenth aspect, a train is provided, comprising a power system as described in the ninth aspect.

[0056] In the eleventh aspect, a permanent magnet synchronous motor is provided, which is applied to mobile equipment, wherein the permanent magnet synchronous motor includes a stator assembly and a rotor assembly, wherein the rotor assembly includes: a rotor core having a plurality of permanent magnet slots evenly distributed along the circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being radially arranged on a side of the corresponding permanent magnet slot close to the rotating shaft, the magnetic conductive blocks being used to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; the magnetic conductive blocks are configured to move to or close to the first position when the speed of the mobile equipment is greater than the first speed to improve the efficiency of the permanent magnet synchronous motor under high-speed conditions.

[0057] In a twelfth aspect, a mobile equipment is provided, comprising the permanent magnet synchronous motor as described in the eleventh aspect.

[0058] In the thirteenth aspect, a permanent magnet synchronous motor is provided, comprising a stator assembly and a rotor assembly, wherein the rotor assembly comprises: a rotor core having a plurality of permanent magnet slots evenly distributed in the circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being radially arranged on a side of the corresponding permanent magnet slot close to the rotating shaft, the magnetic conductive blocks being used to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; the magnetic conductive blocks are also configured to move from the second position to the direction close to the first position to reduce the back electromotive force of the stator assembly when the back electromotive force of the stator assembly increases.

[0059] In a fourteenth aspect, a vehicle is provided, comprising a permanent magnet synchronous motor as described in the thirteenth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic diagram of the structure of a rotor assembly provided in one embodiment of the present application;

[0061] Figure 2 for Figure 1 The simulation results of magnetic field distribution of the rotor assembly in ;

[0062] Figure 3 A schematic structural diagram of a rotor assembly provided in another embodiment of the present application;

[0063] Figure 4 for Figure 3 The simulation results of magnetic field distribution of the rotor assembly in ;

[0064] Figure 5 A schematic diagram of a fixed magnetic bridge in a rotor core provided in an embodiment of the present application;

[0065] Figure 6 A schematic diagram of a fixed magnetic bridge in a rotor core provided by another embodiment of the present application;

[0066] Figure 7 It is a structural schematic diagram of a rotor assembly in the related art;

[0067] Figure 8 for Figure 7 The simulation results of magnetic field distribution of the rotor assembly in ;

[0068] Fig. 9 A schematic diagram of the structure of a rotor core provided in one embodiment of the present application. DETAILED DESCRIPTION

[0069] The embodiments of the present application provide a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The technical solution of the present application is further specifically described below through the embodiments and in combination with the accompanying drawings. In the specification, the same or similar figure numbers indicate the same or similar parts. The following description of the implementation mode of the present application with reference to the accompanying drawings is intended to explain the overall concept of the present application and should not be construed as a limitation on the present application.

[0070] Before introducing the technical solution provided by the embodiments of the present application, the permanent magnet synchronous motor in the related art and the existing problems thereof are described in detail.

[0071] The permanent magnet synchronous motor (PMSM) is mainly composed of a stator assembly, a rotor assembly, a motor housing, etc. The stator assembly includes a stator core and a stator winding wound thereon. When a three-phase current is passed through the stator winding, a rotating magnetic field is generated. The rotating magnetic field interacts with the permanent magnetic field excited by the permanent magnet in the rotor assembly to provide torque for the rotor assembly.

[0072] Permanent magnet motors have a series of advantages such as small size, low weight, and high power density. They can output large torque at low speeds and have excellent low-speed performance. At the same time, my country is rich in rare earth mineral resources, and the manufacturing cost of permanent magnet synchronous motors is low. This makes permanent magnet synchronous motors widely used in electric vehicles, high-speed railways, urban rail transit, aerospace, and industrial production.

[0073] However, permanent magnet synchronous motors also face some practical problems in engineering applications, which are explained in detail below.

[0074] The air gap magnetic field of the permanent magnet synchronous motor is difficult to adjust, resulting in a narrow constant power area and limited width operation. In order to solve this problem, magnetic field weakening control (also known as magnetic field adjustment) can be used to increase the speed.

[0075] The motor magnetic adjustment methods in the related art include AC pulse magnetic adjustment, DC pulse magnetic adjustment and mechanical magnetic adjustment.

[0076] Among them, the AC pulse magnetization method is to apply a direct-axis charging / demagnetizing pulse current to the stator armature winding to realize the magnetization / demagnetization of the permanent magnet, thereby achieving the purpose of adjusting the air gap magnetic density and widening the operation of the motor.

[0077] The DC pulse magnetic modulation method is to set an additional DC magnetic modulation winding dedicated to magnetic modulation on the stator or rotor of the motor to realize the charging / demagnetization of the permanent magnet, or to directly use the motor armature winding to apply the magnetic modulation current.

[0078] The mechanical magnetic adjustment method is to change the magnetic field distribution of the main magnetic circuit of the motor by adding a mechanical mechanism in the stator or rotor, so as to adjust the air gap magnetic density of the motor. The mechanical structure can be, for example, a plurality of slots in the rotor core, and permanent magnets with the same polarity are arranged at both ends of the slots; when the motor speed increases, the permanent magnets that are not fixed will move closer to the air gap under the action of centrifugal force, so that the magnetic resistance of the main magnetic pole leakage magnetic circuit is reduced, the leakage magnetic flux is increased, and the magnetic flux passing through the air gap is reduced, so as to achieve the purpose of reducing the air gap magnetic density when the motor runs at high speed.

[0079] Among the various methods mentioned above, the weakening magnetic current during DC or AC pulse magnetic modulation will lead to higher copper loss, which will reduce the high-speed operation efficiency of the permanent magnet synchronous motor; at the same time, this method also requires the addition of additional components in the circuit part, resulting in increased costs. The existing mechanical magnetic modulation methods are mostly passive adjustments, that is, they cannot actively control their weak magnetic ability, and the weak magnetic ability of this method is limited, and it cannot achieve the expected effect.

[0080] In addition, in some special scenarios, such as for rail transit vehicles such as high-speed railways, when the train has a motor failure or is towed, the motor works in the reverse towing condition. At this time, the three-phase winding of the motor stator is not energized and the rotor is idling under the action of external force. In this case, the winding coil continuously cuts the permanent magnetic field, generating a large induced electromotive force, resulting in a huge circulating current in the winding coil. On the one hand, this current will cause the winding to heat up or even catch fire. On the other hand, the large short-circuit current will generate a pulsating magnetic field, which will interact with the rotor's permanent magnetic field to cause the rotor to vibrate, directly endangering the vehicle's operating safety. At this time, if the permanent magnetic flux of the rotor can be adjusted to 0 or close to 0, there will be no induced electromotive force in the three-phase winding coil, thereby ensuring driving safety.

[0081] Therefore, how to more deeply adjust the permanent magnet magnetic field of the rotor of the permanent magnet synchronous motor has become an urgent problem to be solved.

[0082] In view of the above problems, the embodiments of the present application provide a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The technical solution of the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0083] Figure 1 is a schematic structural diagram of a rotor assembly 10 provided in an embodiment of the present application. The rotor assembly 10 includes a rotor core 11 , permanent magnets 12 and magnetic conductive blocks 13 .

[0084] The rotor core 11 has a plurality of permanent magnet slots 111 evenly distributed along the circumferential direction.

[0085] The circumferential direction mentioned in the embodiment of the present application refers to the circumferential direction surrounding the axial direction of the rotor core 11, and the axial direction refers to the direction where the central axis of the rotor core 11 is located.

[0086] The permanent magnet 12 is disposed in the permanent magnet slot 111 .

[0087] The permanent magnets mentioned in the embodiments of the present application refer to magnets that can maintain magnetism for a long time, such as natural magnets (ferromagnetic ore) and artificial magnets (such as iron-nickel-cobalt magnets, neodymium-iron-boron magnets, and samarium-cobalt magnets, etc.).

[0088] The magnetic conductive blocks 13 are arranged corresponding to the permanent magnet slots 111 , and each magnetic conductive block 13 is arranged radially on a side of the corresponding permanent magnet slot 111 close to the rotating shaft.

[0089] The magnetic conductive block 13 is configured to move between a first position close to the permanent magnet slots 111 and a second position away from the permanent magnet slots 111 to adjust the magnetic field distribution of the rotor assembly 10 .

[0090] According to the principle of minimum magnetic resistance, the magnetic field will be distributed along the direction with smaller magnetic resistance, and the magnetic resistance of the magnetic conductive block 13 is much smaller than that of air. Therefore, in the rotor assembly 10, the magnetic flux lines of the permanent magnetic field generated by the permanent magnet 12 will preferentially pass through the magnetic conductive block; when the position of the magnetic conductive block 13 changes, the magnetic field distribution in the rotor assembly 10 changes accordingly.

[0091] More specifically, when the magnetic conductive block 13 is located at the first position close to the permanent magnet slot 111, the permanent magnetic field of the rotor will gather toward the position of the magnetic conductive block 13; in other words, when the magnetic conductive block is located at the first position close to the permanent magnet slot 111, the permanent magnetic field of the rotor does not pass through the air gap of the rotor assembly; in other words, when the magnetic conductive block is located at the first position close to the permanent magnet slot 111, the air gap magnetic field of the rotor assembly is 0.

[0092] When the magnetic block 13 is located at the second position away from the permanent magnet slot 111, an air gap is formed between the magnetic block 13 and the rotor core 11, and the magnetic resistance at this position is relatively large. The permanent magnetic field of the permanent magnet 12 will preferentially pass through the rotor core with smaller magnetic resistance, and at this time, the magnetic field strength of the air gap magnetic field of the rotor assembly 10 is relatively large.

[0093] In some embodiments, the magnetic conductive block 13 is made of a material with high saturation magnetic induction intensity. The material with high saturation magnetic induction intensity may be, for example, 1J22 alloy, whose saturation magnetic induction intensity can reach 2.4T or above, which is much greater than the saturation magnetic induction intensity of air and silicon steel sheets. The magnetic conductive block made of a material with high saturation magnetic induction intensity can achieve the maximum adjustment requirement for the magnetic flux of the rotor assembly at the minimum size.

[0094] In some embodiments, when the magnetic conductive block 13 is located at the first position, one end of the magnetic conductive block 13 close to the permanent magnet slot 111 along the radial direction abuts against the rotor core 11 .

[0095] That is to say, in the above state, the end face of the magnetic block 13 completely overlaps with the side wall of the rotor core 11, and there is no gap between the magnetic block 13 and the rotor core 11; if there is a gap, the magnetic resistance here will be larger, and it cannot be ensured that the permanent magnetic field of the permanent magnet can be more concentrated in the magnetic block.

[0096] In some embodiments, Figure 1 and 3 As shown, the permanent magnet slots 111 include a first permanent magnet slot 1111 and a second permanent magnet slot 1112. The first permanent magnet slot 1111 and the second permanent magnet slot 1112 are symmetrically arranged about the center line of the D axis. The plurality of first permanent magnet slots 1111 and second permanent magnet slots 1112 in the rotor assembly 10 are arranged alternately and radially.

[0097] The first permanent magnet slot 1111 and the second permanent magnet slot 1112 form a first opening near one end of the rotating shaft, and the width of the magnetic conductive block 13 along the radial direction perpendicular to the radial direction is not less than the width of the first opening, so that the end surface of the magnetic conductive block 13 near one end of the permanent magnet slot 111 can completely cover the first opening. In this way, when the magnetic conductive block 13 is located in the first position, the material with higher magnetic permeability accounts for a larger proportion in the iron core, which is more conducive to guiding the magnetic field into the magnetic conductive block 13.

[0098] In some embodiments, the rotor core 11 has a recessed portion 112 that is recessed toward the permanent magnet slot 111 . The recessed portion 112 is arranged corresponding to the permanent magnet slot 111 and is located on a side of the permanent magnet slot 111 close to the shaft.

[0099] Correspondingly, one end of the magnetic conductive block 13 close to the permanent magnet slot 111 has a protrusion, which matches the shape of the recessed portion 112 . When the magnetic conductive block 13 is located at the first position, the protrusion extends into the recessed portion 112 .

[0100] By providing a protrusion extending toward the permanent magnet slot on the magnetic conductive block 13, when the magnetic conductive block moves to the first position, the permanent magnetic field of the permanent magnet can be more quickly gathered in the magnetic conductive block with smaller magnetic resistance, thereby avoiding the iron core part from reaching saturation first.

[0101] In some embodiments, Figure 1 As shown, the first end of the magnetic conductive block 13 has a first end face 131 and a second end face 132, and the first end face 131 and the second end face 132 form an angle, and the angle is toward the end close to the permanent magnet slot 111. In other words, the first end face 131 and the second end face 132 form a protrusion of the magnetic conductive block 13. The protrusion is set to a V shape, which has a simple structure and is easy to process.

[0102] It should be noted that the distance that the first end of the magnetic conductive block 13 extends outward in the direction close to the permanent magnet slot 111 should not be too long. Figure 1 When the angle between the first end face 131 and the second end face 132 shown in the figure is small, since the recessed portion 112 matches the shape of the magnetic block 13, an air gap will be formed in the permanent magnet slot 111. When the magnetic block 13 is located in the second position, the air gap will form a magnetic barrier, affecting the distribution of the permanent magnetic field of the rotor assembly, resulting in problems such as reduced efficiency of the motor.

[0103] Therefore, in the embodiment of the present application, the angle between the first end face 131 and the second end face 132 is an obtuse angle.

[0104] Of course, the shape of the protrusion is not limited to Figure 1 The form may also be an arc, a rectangle, a polygon (such as a trapezoid), etc.

[0105] In some embodiments, the rotor core 11 has a plurality of slide slots 113 corresponding to the plurality of permanent magnet slots 111. Each slide slot 113 is arranged radially, and a first end of each slide slot 113 in the radial direction is close to the permanent magnet slot 111, and a second end is arranged spaced from the rotating shaft of the rotor assembly 10. The magnetic conductive block 13 can move in the slide slot 113 to move between the first position and the second position.

[0106] It should be understood that the radial direction here can be understood as a direction perpendicular to the aforementioned axial direction.

[0107] The first end of the slide slot 113 has a recessed area 1131 , and the recessed area 1131 matches the shape of the protruding portion of the magnetic conductive block 13 . In other words, the recessed area 1131 forms the recessed portion 112 .

[0108] Of course, the shape of the first end of the slide groove 113 is not limited to Figure 1 In the form of, under the premise that the shape of the magnetic conductive block 13 can match it, the first end of the slide groove 113 can also be an arc shape, a rectangle, a polygon (such as a trapezoid), etc.

[0109] Combine the following Figure 1-Figure 4 The technical solution is further described. Figure 1 The plurality of magnetic conductive blocks 13 shown in FIG. 1 are all located at a second position away from the permanent magnet slots. The distribution of the magnetic field at this time is as follows: Figure 2 As shown; Figure 3 The multiple magnetic blocks in the system are all located at the first position close to the permanent magnet slot. The magnetic field distribution at this time is as follows: Figure 4 shown.

[0110] It should be noted that, for ease of understanding, Figure 2 and Figure 4 Only a partial area of ​​the rotor assembly 10 and the corresponding stator assembly is shown. Figure 2 and Figure 4 In the figure, the closer the color is to orange, the higher the magnetic field strength is, and the closer to blue, the lower the magnetic field strength is.

[0111] When the magnetic block 13 is located at Figure 1 In the second position shown in Figure 2 It can be seen that the magnetic field strength in the air gap between the magnetic conductive block 13 and the rotor core is close to 0, the magnetic flux lines of the permanent magnetic field of the permanent magnet are mostly directed outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly, especially at the end of the core of the stator assembly.

[0112] When the magnetic block 13 is located at Figure 3 When the first position is shown in Figure 4 It can be seen that the magnetic flux lines of the permanent magnetic field of the permanent magnet mostly extend toward the position of the magnetic guide block 13, that is, the permanent magnetic field gathers toward the side away from the air gap, the magnetic field strength at the position of the magnetic guide block is the largest, and the magnetic field strength in the air gap is 0.

[0113] It is understandable that in Figure 1-Figure 4 Only the magnetic field distribution when the magnetic block 13 is at the first position and the second position is shown. In practical applications, the magnetic block 13 can be set at any position between the first position and the second position according to the needs of specific scenarios. When the magnetic block 13 is at different positions, the rotor assembly can present air gap magnetic fields of different strengths.

[0114] According to the above technical solution provided in the embodiment of the present application, by setting a magnetic conductive block corresponding to multiple groups of permanent magnets in the rotor assembly, the position of the magnetic conductive block is adjusted to generate different leakage magnetic fields, thereby achieving the adjustment of the permanent magnetic field, ensuring that the permanent magnet synchronous motor has a wider speed adjustment range, improving the power factor of the permanent magnet motor at high speed, and being able to eliminate or reduce the iron loss of the motor. When the magnetic conductive block moves to one end close to the permanent magnet, the rotor permanent magnetic field can be gathered in the rotor assembly, which can avoid the motor from generating a large circulating current when it is reversely dragged, and ensure the safety of the traction system when the stator winding turns are short-circuited.

[0115] When it is applied to the permanent magnet traction system of railway trains, by adjusting the position of the magnetic block, the magnetic field can be completely cut off from the air gap, so that the motor will not induce potential in the stator winding to generate circulating current in the case of inter-turn short circuit fault, ensuring the fault-oriented safety of the permanent magnet traction motor; when the vehicle is inert, the iron loss of the motor can also be avoided by eliminating the magnetic field; when the vehicle is running at high speed, the position of the magnetic block can be adjusted to adjust the leakage magnetic flux at the magnetic block to achieve the purpose of adjusting the main magnetic field, increase the speed regulation range of the motor, and make the motor have a higher power factor and efficiency under high-speed conditions. This technical solution can fully address the pain points faced by the permanent magnet traction system, solve its safety problems while improving efficiency, and is of great significance to the safe operation of the next generation of permanent magnet traction systems.

[0116] In some embodiments, Figure 1 and 3 As shown, the arc angle of the first permanent magnet slot 1111 and the second permanent magnet slot 1112 close to the rotating shaft end is less than or equal to the arc angle away from the rotating shaft end. In other words, the first permanent magnet slot 1111 and the second permanent magnet slot 1112 in the same permanent magnet slot 111 are arranged in a roughly V shape.

[0117] It should be noted that the first permanent magnet slot 1111 and the second permanent magnet slot 1112 are not connected to each other at one end close to the rotating shaft. The rotor structure with the V-shaped permanent magnet slot has the advantages of small magnetic leakage coefficient, no need to adopt magnetic isolation measures on the rotating shaft, easy control of pole arc coefficient, high mechanical strength of rotor punching, and rotor not easy to deform after installation, and can be applied to multiple fields such as rail transportation and electric vehicles.

[0118] In some embodiments, the first position is located at one end of the first permanent magnet slot 1111 and the second permanent magnet slot 1112 close to the shaft. In other words, the first end of the slide slot 113 is close to the closing end of the V-shaped permanent magnet slot. This can not only achieve the effect of deeply adjusting the magnetic field, but also will not increase the moment of inertia of the rotor too much, and can maintain a high mechanical strength.

[0119] In some embodiments, Figure 5 and Figure 6 As shown, a first magnetic isolation groove 1111a and a second magnetic isolation groove 1111b are provided at both ends of the first permanent magnet slot 1111, and a third magnetic isolation groove 1112a and a fourth magnetic isolation groove 1112b are provided at both ends of the second permanent magnet slot 1112. The function of the above-mentioned multiple magnetic isolation grooves is to prevent the two magnetic poles of the permanent magnets arranged in the permanent magnet slots from directly contacting the rotor core.

[0120] In some embodiments, the second magnetic isolation groove 1111b and the fourth magnetic isolation groove 1112b are connected to the slide groove 113. In this case, the structure of the rotor assembly can be seen in FIG. Figure 1 and Figure 3 .

[0121] In some embodiments, Figure 5 and Figure 6 As shown, the rotor core 11 also has an external magnetic bridge 114 arranged corresponding to the permanent magnet slot 111. More specifically, the external magnetic bridge 114 includes a first external magnetic bridge 114a and a second external magnetic bridge 114b. The first external magnetic bridge 114a is arranged between the first magnetic isolation slot 1111a and the outer edge of the rotor assembly 10, and the second external magnetic bridge 114b is located between the third magnetic isolation slot 1112a and the outer edge of the rotor assembly 10. It should be noted that Figure 5 and Figure 6 The situations where the magnetic conductive blocks 13 are located at two ends of the sliding slot 113 are respectively shown.

[0122] In some embodiments, continue to refer to Figure 5 and Figure 6 The rotor core 11 is also provided with an internal magnetic bridge 115 corresponding to the permanent magnet slot 111. More specifically, the internal magnetic bridge 115 includes a first internal magnetic bridge 115a and a second internal magnetic bridge 115b. The first internal magnetic bridge 115a is located between the slide slot 113 and the second magnetic isolation slot 1111b, and the second internal magnetic bridge 115b is located between the slide slot 113 and the fourth magnetic isolation slot 1112b.

[0123] The first external magnetic bridge 114a and the second external magnetic bridge 114b are provided to increase the structural strength of the rotor core 11. However, the existence of the external magnetic bridges will cause magnetic leakage of the rotor permanent magnets, which will increase the consumption of the permanent magnets.

[0124] The following is an explanation based on a pair of ratios: Figure 7 and Figure 8 Shown is a simulation diagram of a rotor assembly and its magnetic field distribution in the related art.

[0125] like Figure 7As shown, the rotor assembly 30 is provided with a first permanent magnet slot 31a and a second permanent magnet slot 31b, and the first magnetic isolation slot 32a and the second magnetic isolation slot 32b are respectively provided at both ends of the first permanent magnet slot 31a, and the third magnetic isolation slot 33a and the fourth magnetic isolation slot 33b are respectively provided at both ends of the second permanent magnet slot 31b. There are first external magnetic bridges 34a and second external magnetic bridges 34b between the first magnetic isolation slot 32a and the third magnetic isolation slot 33a and the edge of the rotor assembly. The rotor assembly 30 is also provided with a magnetic isolation hole 35, and a first internal magnetic bridge 36a and a second internal magnetic bridge 36b respectively provided between the magnetic isolation hole 35 and the second magnetic isolation slot 32b and the fourth magnetic isolation slot 33b.

[0126] from Figure 8 It can be seen from the simulation results that the permanent magnet first saturates the outer magnetic bridge 35 and the inner magnetic bridge 36. The magnetic field intensity is larger near the magnetic bridge, while some permanent magnets do not participate in the establishment of the main magnetic flux and are invalid parts.

[0127] In view of the above problems, in order to eliminate the adverse effects of the magnetic bridge on the magnetic field distribution, in some embodiments, the first magnetic isolation groove 1111a and the third magnetic isolation groove 1112a penetrate the rotor core 11 in the radial direction; that is, in this embodiment, there is no external magnetic bridge on the rotor core 11, and the structure of the rotor assembly can be referred to as Figure 1 and Figure 3 .

[0128] In the above-mentioned embodiment, since the permanent magnet slots 111 are connected to the outer edge of the rotor core 11 through the magnetic isolation slots, the rotor core and the permanent magnets will be subjected to a large centrifugal force when the rotor assembly 10 rotates at a high speed.

[0129] Therefore, in order to ensure the structural strength of the rotor assembly 10, in some embodiments, as shown in FIG. Figure 1 and Figure 3 As shown, the rotor assembly 10 is further provided with a rotor sleeve 15 which is sleeved on the outer side of the rotor core 11 to improve the strength of the rotor assembly.

[0130] In some embodiments, the rotor sheath 15 is made of carbon fiber or non-magnetic alloy material, which can meet the strength requirements and will not affect the magnetic field distribution of the rotor assembly. By reducing the external magnetic bridge, the air gap width can be increased, which is also conducive to reducing the leakage magnetic flux on the side of the magnetic conductive block.

[0131] In some embodiments, Fig. 9 As shown, the rotor core 11 includes a core shaft core 11a, a D-axis core 11b and a Q-axis core 11c. The core shaft core 11a is a sleeve close to the axis of the rotor core 11, the D-axis core 11b is located between the first permanent magnet slot 1111 and the second permanent magnet slot 1112, and the Q-axis core 11c is located between two adjacent permanent magnet slots 111.

[0132] It should be noted that Fig. 9 The dotted lines in FIG. 1 are for the purpose of facilitating the description and understanding of the various parts of the rotor core 11 , and do not mean that the core axis core 11 a , the D axis core 11 b and the Q axis core 11 c are separated from each other.

[0133] In some embodiments, the core shaft core 11a, the D-axis core 11b and the Q-axis core 11c are integrally formed. The integral forming method is simple in process and can reduce the processing cost of the rotor core.

[0134] In some embodiments, the mandrel core 11 a , the D-axis core 11 b , and the Q-axis core 11 c are a combined structure, which may be made of different materials.

[0135] The D-axis core 11 b is made of silicon steel material, amorphous material or nanocrystalline material. Such materials have low iron loss and can reduce the heat generation of the rotor core.

[0136] The Q-axis core 11c is made of silicon steel material, amorphous material or nanocrystalline material. The silicon steel material is oriented in the axial direction and has a high magnetic permeability; the nanocrystalline material also has a high magnetic permeability, which can reduce the heating of the rotor assembly while realizing the miniaturization and lightness of the motor.

[0137] In some embodiments, the core shaft core 11a and the Q-axis core 11c are integrally formed and can be made of the same material, which can reduce the number of processing steps.

[0138] In some embodiments, the core shaft core 11a and the Q-axis core 11c can be connected by a dovetail structure; specifically, the core shaft core 11a is a sleeve structure, and a plurality of dovetail grooves are distributed axially on its outer surface; a dovetail-shaped protrusion is provided at one end of the Q-axis core 11c close to the core shaft core 11a, which is inserted into the dovetail groove of the core shaft core 11a to combine the Q-axis core 11c and the core shaft core 11a. Compared with the method of integrally forming the core shaft and the Q-axis core, this technical solution can significantly improve the utilization rate of materials and save manufacturing costs.

[0139] In some embodiments, the rotor assembly 10 further includes a driving mechanism to drive the magnetic conductive block 13 to move in the slide slot 113 .

[0140] An embodiment of the present application provides a permanent magnet synchronous motor, including a rotor assembly and a stator assembly, wherein the rotor assembly is the rotor assembly described in any of the above embodiments.

[0141] The permanent magnet synchronous motor can be applied in various fields such as aviation, national defense, industrial and agricultural production and daily life. Specifically, the motor can be applied to industrial drive devices, automation equipment, fans, pumps, compressors, machine tools, robots, and vehicles.

[0142] The vehicles may include land vehicles, air vehicles, water vehicles, industrial equipment, agricultural equipment or recreational equipment, etc.

[0143] Exemplarily, the water transportation vehicle may be a hovercraft, a motorboat, a motorboat, a fishing boat, a cruise ship, a sailboat, a yacht or other vessel.

[0144] The air transportation means may be an airplane, and the land transportation means may be a vehicle.

[0145] In some embodiments, the vehicle is a transportation vehicle. Exemplarily, the vehicle is one of a commercial vehicle, a passenger car, a motorcycle, a flying car, and a train.

[0146] In some embodiments, the vehicle is an industrial vehicle or an engineering vehicle. Exemplarily, the vehicle is one of a forklift, a trailer, a tractor, an excavator, a bulldozer, and a crane.

[0147] In some embodiments, the vehicle may be an electric vehicle or a fuel vehicle, wherein the vehicle is exemplarily one of a pure electric vehicle / battery electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV) and a plug-in hybrid electric vehicle (PHEV).

[0148] In some embodiments, the vehicle may also be agricultural equipment (such as a lawn mower, a harvester, etc.), amusement equipment, a toy vehicle, etc.

[0149] In some embodiments, the vehicle may also be a high-speed railway train, an EMU train, an urban rail transit vehicle, etc.

[0150] The embodiments of the present application also provide a permanent magnet synchronous motor, a power system and an urban rail transit vehicle.

[0151] The total energy consumption of urban rail transit systems can be divided into station operation energy consumption and train operation energy consumption. Among them, station operation energy consumption includes the energy consumption of station lighting, air conditioning and elevators, etc. The energy consumption value of this part is relatively fixed and accounts for a small proportion of the overall energy consumption; vehicle energy consumption is mainly traction energy consumption during train operation. As an important link in the traction system that undertakes energy conversion, improving the efficiency of traction motors under various working conditions is an important measure to reduce train energy consumption.

[0152] The distance between stations in urban rail systems is usually short, and the operation process of vehicles between two stations includes three sections: acceleration-coasting-deceleration. When leaving the station, the vehicle accelerates from a standstill to the maximum speed, after which the vehicle coasts for a distance and starts braking until it stops when approaching the next station. Alternatively, when the interval distance is long, the vehicle may experience a second acceleration section and a second coasting section after the coasting section, that is, a second acceleration after coasting. In other words, the power system of this type of vehicle needs to be started and stopped frequently, and there are many coasting conditions.

[0153] From the perspective of urban rail vehicles' demand for traction electric drive systems, in order to improve operating efficiency, urban rail transit vehicles need to have the largest possible acceleration / deceleration within the acceleration and braking range, which requires a larger torque during the starting and braking stages.

[0154] At present, urban rail transit vehicles widely use asynchronous induction motors as their drive motors. Among them, the asynchronous induction motor provides an excitation magnetic field by the rotor winding, and generates a rotating magnetic field when a three-phase current is passed through the stator winding. The rotating magnetic field interacts with the excitation magnetic field of the rotor winding to provide torque for the rotor. In the above process, there will be a large loss in the process of forming the excitation magnetic field in the rotor winding.

[0155] The permanent magnet synchronous motor uses permanent magnets for excitation, and its rotor magnetic field is completely generated by permanent magnet materials. There is no additional energy consumption in the process of generating the excitation magnetic field. When it is applied to urban rail transit vehicles, it can greatly reduce the loss of the motor.

[0156] However, there will be a long idling interval during the operation of urban rail transit vehicles, during which the rotor will idle due to the inertia of the vehicle. For asynchronous motors, as long as the excitation current of the stator and rotor is disconnected, the stator and rotor magnetic fields will disappear, thereby disconnecting the coupling between the stator and the rotor; while for permanent magnet synchronous motors, during the idling of the rotor, the permanent magnetic field of the rotor does not disappear, and the magnetic field will couple with the stator core, causing excessive iron loss in the stator core, thereby affecting the performance of the motor, which is not conducive to reducing the energy consumption of the entire power system.

[0157] The permanent magnet synchronous motor provided in the embodiment of the present application is applied to the power system of an urban rail transit vehicle and is dedicated to solving the problem of poor energy saving effect of an urban rail transit vehicle due to high iron loss under light load or no-load conditions.

[0158] The urban rail transit vehicles mentioned here may include subway trains, light rail trains, monorail trains, trams, etc.

[0159] The permanent magnet synchronous motor comprises a rotor assembly and a stator assembly. The structure of the rotor assembly can be seen in Figure 1 The rotor assembly 11 includes a rotor core 11, a permanent magnet 12 and a magnetic conductive block 13. The specific structure of the rotor assembly 11 has been described in detail above and will not be repeated here.

[0160] In the embodiment of the present application, the magnetic conductive block 13 is configured as follows: when the vehicle is in the coasting condition, the magnetic conductive block 13 is located at the first position close to the permanent magnet slot 111 to reduce the iron loss of the permanent magnet synchronous motor 1 in the coasting condition.

[0161] According to the principle of minimum magnetic resistance, the magnetic field will be distributed along the direction of smaller magnetic resistance. When the magnetic conductive block 13 is located at the first position close to the permanent magnet slot 111, since its magnetic resistance is much smaller than that of the air, the rotor permanent magnet magnetic field will preferentially pass through the magnetic conductive block 13, causing the magnetic field to gather in the magnetic conductive block 13, which will reduce the air gap magnetic field strength of the rotor assembly 10.

[0162] When the permanent magnetic field of the rotor assembly 10 is reduced, when the motor is towed, the coupling effect between the rotor assembly 10 and the stator assembly 20 is weakened, thereby reducing the iron loss of the motor.

[0163] The magnetic block 13 in the embodiment of the present application is also configured as follows: when the vehicle is in traction mode, the magnetic block 13 is located at a second position away from the permanent magnet slot 111. In this case, an air gap is formed between the magnetic block 13 and the rotor core 11, and the magnetic resistance at this position is relatively large. The permanent magnetic field of the permanent magnet 12 will preferentially pass through the rotor core 11 with relatively small magnetic resistance, and the air gap magnetic field strength of the rotor assembly 10 can be increased at this time. The magnetic coupling between the rotor permanent magnetic field and the stator winding magnetic field is relatively strong, so that the permanent magnet synchronous motor can output a relatively large torque, thereby ensuring the traction performance of the motor.

[0164] When the magnetic block 13 is located at Figure 1 In the second position shown in Figure 2It can be seen that the magnetic field strength in the air gap between the magnetic conductive block 13 and the rotor core 11 is close to 0, the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 are mostly directed outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly 10, especially at the end of the core of the stator assembly 20. At this time, a strong coupling is generated between the three-phase winding magnetic field and the rotor permanent magnetic field, so that the rotor assembly 10 can output a larger power, and the motor has a better traction performance.

[0165] When the magnetic block 13 is located at Figure 3 When the first position is shown in Figure 4 It can be seen that the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the position of the magnetic guide block 13, that is, the permanent magnetic field gathers to the side away from the air gap, the magnetic field strength at the position where the magnetic guide block 13 is located is the largest, and the magnetic field strength in the air gap is 0. When the motor is dragged to make the rotor assembly rotate freely, since the air gap magnetic field strength is small at this time, the interaction between it and the stator core 20 is weakened, thereby reducing the iron loss of the motor.

[0166] That is to say, according to the above technical solution provided in the embodiment of the present application, by setting an adjustable magnetic block in the permanent magnet synchronous motor rotor assembly, the position of the magnetic block is adjusted according to the operating conditions of the urban rail transit vehicle, so that the motor iron loss can be reduced and energy can be saved under the vehicle idling condition; at the same time, the traction performance of the motor can be ensured under the traction condition.

[0167] For existing permanent magnet synchronous motors, the air gap magnetic field strength is determined by the permanent magnets in the rotor assembly, and its adjustment is relatively difficult, which results in a narrow constant power range. Especially at high speeds, the efficiency of the motor will be significantly reduced. When applied to urban rail transit vehicles, the traction performance will be significantly reduced at high traction speeds.

[0168] Therefore, in some embodiments of the present application, the magnetic block 13 is also configured as follows: when the speed of the vehicle is greater than a first speed threshold, the magnetic block 13 moves between the first position and the second position to adjust the magnetic field distribution of the rotor assembly 10 and increase the speed regulation range of the permanent magnet synchronous motor 1.

[0169] In the previous article Figure 1-Figure 4 Only the magnetic field distribution of the magnetic block 13 at the first position and the second position, which are two extreme positions, is shown, which correspond to the minimum magnetic field and the maximum magnetic field, respectively. When the magnetic block 13 is set at any position between the first position and the second position, the rotor assembly 10 can present air gap magnetic fields of different intensities.

[0170] The first speed threshold may be the vehicle speed when the permanent magnet synchronous motor runs at the rated speed, for example, 60 km / h, 80 km / h or 100 km / h, etc. The embodiment of the present application does not specifically limit this, and may be determined by the specific parameters of the drive and transmission mechanism of the vehicle's traction system.

[0171] When the speed of the vehicle exceeds the first speed threshold, the permanent magnet synchronous motor will exceed the constant power range, resulting in a decrease in traction performance. In this case, the position of the magnetic conductive block 13 can be adjusted, for example, by moving it from the second position to a direction close to the first position, changing the magnetic field distribution of the rotor assembly 10 to achieve the purpose of magnetic field weakening and speed expansion.

[0172] In some embodiments, when adjusting the position of the magnetic conductive block, the specific position of the magnetic conductive block can be determined according to the speed of the vehicle. For example, it can be determined according to the difference between the current speed of the vehicle and the first speed threshold, the larger the difference is, the farther the magnetic conductive block is from the second position, and vice versa, the smaller the difference is, the closer the magnetic conductive block is to the second position.

[0173] According to this technical solution, a movable magnetic conductive block is used to achieve weak magnetic speed expansion in a high-speed scenario, which can avoid the problems of increased cost and energy consumption caused by the technical solution of applying a demagnetization current to perform weak magnetic speed expansion in the related art.

[0174] The present application also provides a power system for urban rail transit vehicles, which is used to provide power for urban rail transit vehicles. The power system is also called an electric transmission system for urban rail transit vehicles, and the power system includes a permanent magnet synchronous motor as described in any of the above embodiments.

[0175] The present application also provides an urban rail transit vehicle, comprising a permanent magnet synchronous motor or a power system as described in any of the above embodiments. The urban rail transit vehicle may be a subway train, a light rail train, a monorail train, a tram, etc.

[0176] The embodiment of the present application also provides a permanent magnet synchronous traction motor, a traction system and a locomotive, which are used to solve the technical problems faced by the permanent magnet traction technology in the locomotive field.

[0177] Locomotives are important tools for railway transportation, used to pull or push railway vehicles, and their traction mass can usually reach several times or dozens of times their own. The technical solution provided in the embodiment of the present application is mainly applied to the traction locomotives of freight trains. For freight trains, the first issue to be considered is heavy load, that is, the maximum traction force (continuous traction force) needs to be exerted, and on this basis, the locomotive can be ensured to pass the ramp at a higher speed (i.e. continuous speed). The maximum speed of the locomotive is a manifestation of its rapid transportation capability, which must also be guaranteed.

[0178] According to the different power units, locomotives can be divided into diesel locomotives and electric locomotives.

[0179] Internal combustion locomotives usually use internal combustion engines such as diesel engines as their power source. The operation of the internal combustion engine drives the generator, and the electrical energy generated by the generator is transmitted to the electric motor, which converts the electrical energy into mechanical energy. The kinetic energy is then transmitted to the locomotive drive wheels through a transmission system such as a speed change gear, thereby towing the vehicle. This type of internal combustion locomotive is also called an electric transmission locomotive. The maximum power of this type of locomotive is limited by the power of the internal combustion engine, which limits its traction capacity.

[0180] Electric locomotives have fast starting and acceleration, strong climbing ability, are not affected by severe cold, and do not emit exhaust gas when running, making them the main force of modern railway transportation.

[0181] For electric locomotives, the electric drive system composed of its traction motor and its control system is the most critical component, which plays a decisive role in the performance of the whole vehicle. The development of the electric drive system of electric locomotives has gone through DC drive, asynchronous drive and permanent magnet synchronous drive system.

[0182] Early locomotives widely used DC transmission systems. With the development of control technology, thanks to the improvement of the speed regulation performance of the AC asynchronous motor speed regulation system using field-oriented vector control technology, coupled with the advantages of the asynchronous motor itself, it has been widely used in locomotive electric transmission systems and has become the current mainstream.

[0183] Permanent magnet synchronous motors do not require rotor excitation current during operation and have a series of advantages such as small size, low weight, and high power density; they can output large torque at low speeds and have excellent low-speed performance; at the same time, my country is rich in rare earth mineral resources and the manufacturing cost of permanent magnet synchronous motors is relatively low, making the application of electric transmission systems based on permanent magnet synchronous motors in locomotives one of the research hotspots in recent years.

[0184] As mentioned above, locomotives have the characteristics of low speed and heavy load. Their continuous operating speed is generally 20-25Km / h, and the maximum operating speed is usually not more than 120Km / h. This requires the electric transmission system to be able to output constant power within a wide speed range.

[0185] For permanent magnet synchronous motors, they can provide greater torque at low speeds to ensure the low-speed traction performance of the locomotive; but this type of motor has a small speed regulation range. Under high-speed conditions, the operating range of the permanent magnet synchronous motor may exceed its constant power range, which will result in the inability to provide the required traction force under high-speed conditions, resulting in limited traction performance.

[0186] The permanent magnet synchronous traction motor provided in the embodiment of the present application can ensure constant power output within a wide speed range, thereby ensuring the traction performance of the locomotive.

[0187] The permanent magnet synchronous motor comprises a stator assembly and a rotor assembly, wherein the rotor assembly comprises a rotor core, a permanent magnet and a magnetic conductive block, see the above Figure 1 As described above, the specific structure of the rotor assembly will not be repeated here.

[0188] See also Figure 1 In this embodiment, the magnetic conductive block 13 is configured to move between a first position close to the permanent magnet slot 111 and a second position away from the permanent magnet slot 111 according to the running speed of the locomotive, and adjust the magnetic field distribution of the rotor assembly 10 so that the permanent magnet synchronous traction motor 1 outputs constant power when driving the locomotive to operate within its operating speed range.

[0189] The saturation magnetic induction intensity of the magnetic conductive block 13 is much greater than that of air and silicon steel sheets, and its magnetic resistance is small. The rotor permanent magnetic field will preferentially pass through the magnetic conductive block 13, and gather the magnetic field near the magnetic conductive block 13. When the magnetic conductive block 13 moves between the first position and the second position, it will have different effects on the distribution of the rotor permanent magnetic field. Therefore, in the technical solution of the present application, the position of the magnetic conductive block can be adjusted according to the running speed of the locomotive, thereby changing the magnetic field distribution of the rotor assembly, so that the permanent magnet synchronous traction motor can output at constant power.

[0190] When the magnetic block 13 is located at Figure 1 In the second position shown in Figure 2 It can be seen that the magnetic field strength in the air gap between the magnetic conductive block 13 and the rotor core 11 is close to 0, the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 are mostly directed outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly 10, especially at the end of the core of the stator assembly 20. At this time, the stator three-phase winding magnetic field is strongly coupled with the rotor permanent magnetic field, and the rotor assembly 10 can output a large torque, which is suitable for low-speed conditions such as climbing or starting.

[0191] When the magnetic block 13 is located at Figure 3 When the first position is shown in Figure 4 It can be seen that the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the position of the magnetic guide block 13, that is, the permanent magnetic field gathers to the side away from the air gap, the magnetic field strength at the position where the magnetic guide block 13 is located is the largest, and the magnetic field strength in the air gap is close to 0. In this case, the magnetic guide block 13 is used to achieve weak magnetic field of the rotor assembly. At this time, the permanent magnet synchronous traction motor 1 can maintain a substantially constant output power while rotating at high speed, and is suitable for the aforementioned high-speed driving conditions.

[0192] It should be noted that the above only describes the situation when the magnetic block 13 is in the first position and the second position. When the magnetic block 13 is located at different positions between the first position and the second position, the rotor assembly 10 will present different magnetic field distributions; the closer to the first position, the smaller the permanent magnetic field strength of the rotor assembly 10, and the closer to the second position, the greater the permanent magnetic field strength. In practical applications, the position of the magnetic block 13 can be determined according to the speed of the locomotive so that the traction motor can output constant power over the entire speed range.

[0193] According to the above technical solution provided in the present application, a movable magnetic conductive block is arranged in the rotor assembly of the permanent magnet synchronous traction motor. During the operation of the locomotive, the position of the magnetic conductive block is adjusted according to the operating speed of the locomotive to change the magnetic field distribution of the rotor assembly, so that the permanent magnet synchronous traction motor can output constant power within the operating speed range of the locomotive, thereby improving the traction capacity and operating efficiency of the locomotive.

[0194] In some embodiments, the magnetic conductive block 13 is further configured to be located at or near the first position when the speed of the locomotive is greater than a first speed, so as to reduce the air gap magnetic field strength of the rotor assembly and increase the speed of the permanent magnet synchronous traction motor. The first speed is related to the rated speed of the permanent magnet synchronous traction motor.

[0195] The above-mentioned first speed can be the speed of the locomotive when the permanent magnet synchronous traction motor runs at the rated speed, for example, it can be 100km / h or 120km / h, etc. The embodiment of the present application does not specifically limit this, and it can be determined according to the specific parameters of the drive and transmission mechanism of the traction system of the locomotive. The smaller the first speed, the narrower the demand for the constant power range of the permanent magnet synchronous traction motor. When the speed of the locomotive exceeds the first speed, the traction motor may operate outside the constant power range, which will cause the traction performance of the locomotive to decrease. In this case, the magnetic conductive block can be moved in the direction close to the first position to change the magnetic field distribution of the rotor assembly, thereby achieving the purpose of weak magnetic speed expansion.

[0196] In the above technical solution, under high-speed conditions, the movement of the magnetic conductive block is utilized to realize weak magnetic field speed expansion of the permanent magnet synchronous traction motor, so that it can maintain constant power output at high speed, avoiding the problems of increased cost and energy consumption caused by the existing technical solution of applying demagnetization current for weak magnetic field speed expansion.

[0197] An embodiment of the present application also provides a traction system applied to a locomotive, which may be an electric-driven diesel locomotive or an electric locomotive. The traction system includes a permanent magnet synchronous traction motor as described above.

[0198] The present application also provides a locomotive, including the permanent magnet synchronous traction motor or traction system described above.

[0199] The locomotive may be, for example, an electric transmission internal combustion locomotive, which drives a generator through an internal combustion engine, and the generator generates electric energy and transmits it to a synchronous traction motor or a traction system to pull the vehicle. Alternatively, the locomotive may also be an electric locomotive, which may store electric energy through a battery or receive electric energy from a contact network through a pantograph, and a permanent magnet synchronous traction motor or a traction system converts the received electric energy into mechanical energy to pull the vehicle.

[0200] The embodiments of the present application also provide a power system and a train, which are dedicated to solving the safety problem of permanent magnet synchronous motors in the power systems of railway vehicles, especially high-speed railway vehicles, when inter-turn short circuit faults occur.

[0201] When a short-circuit fault occurs in some or all of the permanent magnet synchronous motors in the train power system, the vehicle cannot stop immediately due to its huge inertia. Especially for high-speed EMU trains and high-speed railway trains, when the running speed is 350km / h, the braking distance is about 6,500 meters; when the speed reaches 400km / h, the braking distance will increase to 9,100 meters.

[0202] During the above braking process, the motor in the train power system works in the reverse drag condition, and the rotor in the motor is dragged and idling at high speed. Since the rotor assembly of the permanent magnet synchronous motor uses permanent magnets for excitation, the rotor permanent magnetic field does not disappear when the motor is idling; that is, the electromagnetic coupling between the stator and rotor assemblies is not eliminated at this time, and the stator winding cuts the permanent magnetic field, generating a large circulating current inside it.

[0203] The circulating current in the stator winding will cause the winding to heat up, resulting in a sharp increase in the temperature inside the motor housing, which puts the permanent magnet at risk of high-temperature demagnetization. At the same time, when the temperature is too high, it will cause the winding to catch fire. If the fire spreads in a high-speed EMU train, it will cause huge loss of life and property. The huge short-circuit current in the stator winding will generate a pulsating magnetic field, which may interact with the rotor permanent magnet magnetic field, causing the motor to vibrate strongly, and then drive the car body to vibrate, which will threaten the operation safety of high-speed EMU trains. In addition, even if the vehicle can stop quickly in the event of a fault, it needs to be towed back to the depot by other vehicles. In this process, the inter-turn short circuit will still expand further, and there is still a risk of causing a fire.

[0204] The power system provided in the embodiment of the present application can reduce the probability of safety accidents and achieve fault-guided safety when a turn-to-turn short circuit fault occurs in a permanent magnet synchronous motor. The power system is applied to trains. The train mentioned here can be any one of a conventional train, a fast train, an EMU train and a high-speed train. The embodiment of the present application does not make specific limitations on this.

[0205] The power system includes a plurality of permanent magnet synchronous motors for driving the train. The permanent magnet synchronous motors include a stator assembly and a rotor assembly. The rotor assembly includes a rotor core, a permanent magnet and a magnetic conductive block. The structure of the rotor assembly can be seen in Figure 1 , I will not go into details here.

[0206] The magnetic block 13 is configured to move between a first position close to the permanent magnet slot 111 and a second position away from the permanent magnet slot 111 to adjust the magnetic field distribution of the rotor assembly 10. When the magnetic block 13 is located at the first position close to the permanent magnet slot 111, the rotor permanent magnetic field will gather toward the position of the magnetic block 13; or, in other words, when the magnetic block is located at the first position close to the permanent magnet slot 111, the rotor permanent magnetic field does not pass through the air gap of the rotor assembly; or, in other words, when the magnetic block is located at the first position close to the permanent magnet slot 111, the air gap magnetic field of the rotor assembly is 0. When the magnetic block 13 is located at the second position away from the permanent magnet slot 111, an air gap is formed between the magnetic block 13 and the rotor core 11, and the magnetic resistance at this position is relatively large. The permanent magnetic field of the permanent magnet 12 will preferentially pass through the rotor core with smaller magnetic resistance, and at this time, the magnetic field strength of the air gap magnetic field of the rotor assembly 10 is relatively large.

[0207] The power system in the embodiment of the present application is configured as follows: when a turn-to-turn short circuit fault occurs in a target permanent magnet synchronous motor among multiple permanent magnet synchronous motors, the magnetic conductive block in the target synchronous motor is switched to a first position to short-circuit the main magnetic flux of the target permanent magnet synchronous motor, so that the target permanent magnet synchronous motor is taken out of service.

[0208] There are multiple permanent magnet synchronous motors in the power system in the embodiment of the present application. The above-mentioned target permanent magnet synchronous motor is the motor in which the short-turn fault occurs. The number of the target permanent magnet synchronous motors can be one or more, and the embodiment of the present application does not limit this.

[0209] The target permanent magnet synchronous motor can be determined based on the current or temperature of the stator windings of multiple permanent magnet synchronous motors in the power system. For example, during the operation of the power system, the current of the stator windings of the multiple motors is monitored. When the winding current of one or more of the motors increases abnormally, it can be determined that there is a risk of failure, and the motor can be determined as the target permanent magnet synchronous motor. Alternatively, since the temperature of the motor will rise rapidly when a short turn fault occurs, the temperature of each motor can also be detected. When the temperature of one or more of the motors increases abnormally, it is determined that there is a risk of a short turn fault.

[0210] According to the above description, when the magnetic conductive block 13 is in the first position, the rotor permanent magnetic field will not pass through the air gap of the rotor assembly, that is, in this case, the air gap magnetic field strength of the rotor assembly is close to 0. When the rotor assembly 10 is reversely dragged and idling, since the air gap magnetic field strength is extremely low, the rotor assembly 10 will not generate magnetic coupling with the stator winding, so there will be no risks such as circulating current, heating and vibration, which can ensure the safety of the target permanent magnet synchronous motor.

[0211] According to the above-mentioned technical means, in order to meet the demand for completely eliminating the rotor magnetic field of the faulty target motor during train operation, the movable magnetic conductive blocks in the rotor assembly are used to weaken the magnetic flux of the rotor assembly of the target motor, so that the target motor is withdrawn from service, avoiding the impact on train safety, and realizing fault-guided safety.

[0212] An embodiment of the present application also provides a train, comprising a power system as described above.

[0213] The embodiments of the present application also provide a permanent magnet synchronous motor and mobile equipment. The technical solution is applied to the field of mobile equipment such as vehicles to solve the following technical problems in this field.

[0214] The rotor magnetic field of the permanent magnet synchronous motor is generated by the permanent magnets in the rotor assembly. When the vehicle is in high-speed operation, the stator winding cuts the rotor magnetic field to generate back electromotive force. On the one hand, the existence of back electromotive force will increase the temperature of the stator winding, and there may be a risk of permanent magnet demagnetization under unfavorable heat dissipation; on the other hand, when the back electromotive force increases, the motor will lose its speed-up ability. At this time, if you want to continue to increase the speed, you need to weaken the magnetic field of the rotor permanent magnet.

[0215] At present, the most commonly used weakening magnetic field method is to apply direct-axis weakening magnetic field current, which can reduce the back electromotive force in the stator winding and increase the motor speed. When performing weakening magnetic field control, the energy provided to the permanent magnet synchronous motor will also be divided into two parts, one part is used to provide torque, and the other part is used for weakening magnetic field, which will increase the energy consumption of the motor and reduce the efficiency under high-speed conditions.

[0216] The technical solution provided in the embodiment of the present application can reduce the loss of the permanent magnet synchronous motor and improve its efficiency.

[0217] The permanent magnet synchronous motor provided in the embodiment of the present application is applied to a mobile device to provide power for the mobile equipment. The mobile equipment may be an electric vehicle using a permanent magnet synchronous motor as a power source, including land vehicles, air vehicles, water vehicles, industrial equipment, agricultural equipment or entertainment equipment, etc. Exemplarily, the water vehicle may be a hovercraft, a motorboat, a motorboat, a fishing boat, a cruise ship, a sailboat, a yacht or other ships, the air vehicle may be an airplane, and the land vehicle may be a vehicle.

[0218] In some embodiments, the vehicle is a transportation vehicle. Exemplarily, the vehicle is one of a commercial vehicle, a passenger car, a motorcycle, a flying car, and a train.

[0219] In some embodiments, the vehicle is an industrial vehicle or an engineering vehicle. Exemplarily, the vehicle is one of a forklift, a trailer, a tractor, an excavator, a bulldozer, a crane, and an electric wheel mining truck.

[0220] In some embodiments, the vehicle may be an electric vehicle or a hybrid electric vehicle, wherein the vehicle is exemplarily one of a pure electric vehicle / battery electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV) and a plug-in hybrid electric vehicle (PHEV).

[0221] In some embodiments, the vehicle may also be agricultural equipment (such as a lawn mower, a harvester, etc.), amusement equipment, a toy vehicle, etc.

[0222] The permanent magnet synchronous motor provided in the embodiment of the present application includes a stator assembly and a rotor assembly. The structure of the rotor assembly can be seen in Figure 1 As well as the previous description, I will not repeat it here.

[0223] The magnetic conductive block 13 is configured to move to the first position or close to the first position when the speed of the mobile equipment is greater than the first speed, so as to improve the efficiency of the permanent magnet synchronous motor under high-speed conditions.

[0224] It should be understood that the first speed is related to the inherent parameters of the permanent magnet synchronous motor used in the mobile equipment. For example, the first speed can be determined according to the maximum speed of the permanent magnet synchronous motor in the constant power area; or, the first speed can also be determined according to the rated speed of the permanent magnet synchronous motor. When the vehicle speed is greater than the first speed, it is considered to be in a high-speed operating condition.

[0225] It should also be noted that the first speeds are usually different for different types of mobile equipment. For example, for a mining truck, in order to ensure a larger traction capacity, the reduction ratio of its transmission mechanism is usually higher, and the moving speed is usually slower. In this case, the corresponding first speed is lower, such as 15km / h or 20km / h. For another example, for an electric car, its moving speed is usually faster, and the first speed may be, for example, 100km / h, 120km / h or higher.

[0226] When the speed of the mobile equipment is high, as mentioned above, the method of applying the demagnetization current is less efficient. In the technical solution of the present application, the above-mentioned movable magnetic conductive block can be used to adjust the permanent magnetic field of the rotor assembly, which can also achieve the purpose of magnetic weakening. Since this method does not require the provision of demagnetization current, this part of energy is saved, thereby improving the energy efficiency of the permanent magnet synchronous motor.

[0227] like Figure 2 As shown, when the magnetic block 13 is located at the first position, the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 mostly extend toward the position of the magnetic block 13, that is, the permanent magnetic field gathers to the side away from the air gap, the magnetic field strength at the position where the magnetic block 13 is located is the largest, and the magnetic field strength in the air gap is 0.

[0228] When the magnetic conductive block 13 is located at the second position, the structure of the permanent magnet synchronous motor and the corresponding magnetic field distribution are as follows: Figure 3 and Figure 4 shown.

[0229] from Figure 3 and Figure 4 It can be seen that when the magnetic block 13 is in the second position, the magnetic flux lines of the permanent magnetic field of the permanent magnet 12 are mostly oriented outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly 10, especially at the end of the iron core of the stator assembly 20. When the mobile equipment is operating normally, the magnetic block 13 can be kept in this position to enable the permanent magnet synchronous motor to exert its maximum capacity and output constant power to ensure the low-speed traction and acceleration capabilities of the vehicle.

[0230] It is also understandable that Figure 1-Figure 4 Only the magnetic field distribution when the magnetic block 13 is located at the first position and the second position, two extreme positions, is shown. In fact, the magnetic block 13 can move between the two positions. Since the magnetic resistance of the magnetic block 13 is much smaller than that of the air, the permanent magnetic field of the rotor will move in the direction of smaller magnetic resistance. Therefore, when the position of the magnetic block 13 changes, the magnetic field distribution of the rotor assembly 10 changes accordingly. The closer the magnetic block 13 is to the first position, the smaller the air gap magnetic field strength is. Conversely, the closer the magnetic block 13 is to the second position, the greater the magnetic field strength is. Therefore, in the technical solution of the embodiment of the present application, in order to improve the efficiency under high-speed conditions, the magnetic block 13 can be moved to the first position or close to the first position.

[0231] An embodiment of the present application also provides a mobile equipment, including the permanent magnet synchronous motor as described above.

[0232] The embodiments of the present application also provide a permanent magnet synchronous motor and a vehicle, which are used to solve the safety problem caused by the large back electromotive force when the permanent magnet synchronous motor rotates at high speed.

[0233] The rotor assembly of a permanent magnet synchronous motor is embedded with rare earth permanent magnets with very high magnetic field strength. When the rotor rotates, the magnetic flux passing through the coil of the stator winding will change greatly. According to the law of electromagnetic induction, the stator winding coil will generate an electromotive force due to the changing magnetic field. The magnitude of the electromotive force is proportional to the number of coil turns of the stator winding, the air gap magnetic field strength, and the rotor speed. For a permanent magnet synchronous motor, the number of coil turns and the air gap magnetic field strength are usually constant values. Therefore, the higher the motor speed, the greater the back electromotive force.

[0234] The existence of back EMF in the stator winding will have many adverse effects on the operation of the permanent magnet synchronous motor. First, the back EMF will offset the potential difference in the original stator winding, which will cause the stator magnetic field to fluctuate, and then cause the motor to vibrate, affecting the overall structure and performance of the motor; secondly, the existence of back EMF will reduce the actual working voltage of the motor, affecting the performance and active power of the motor; thirdly, when the back EMF is large, it will cause the stator winding coil to heat up or even catch fire, which will cause safety hazards such as fire.

[0235] In order to ensure the performance of the permanent magnet synchronous motor at high speed, in the related technology, a feasible method to reduce the back electromotive force is to weaken the rotor by applying a d-axis demagnetization current to reduce the air gap magnetic field strength, thereby ensuring the motor performance at the current higher speed, while also increasing the speed range of the motor operation.

[0236] However, increasing the demagnetization current will lead to higher copper loss, which will reduce the efficiency of the motor when running at high speed. At the same time, this method also requires adding additional components to the circuit part, resulting in an increase in the cost of the whole machine.

[0237] The permanent magnet synchronous motor and vehicle provided in the embodiments of the present application can suppress the back electromotive force of the permanent magnet synchronous motor under high-speed conditions and expand the operating range of the permanent magnet synchronous motor. The technical solution is described in detail below.

[0238] The permanent magnet synchronous motor comprises a stator assembly and a rotor assembly, wherein the rotor assembly comprises a rotor core, a permanent magnet and a magnetic conductive block. The structure of the rotor assembly is shown in Figure 1 As well as the previous description, I will not repeat it here.

[0239] In the embodiment of the present application, the magnetic conductive block 13 is configured to move from the second position toward the first position when the back electromotive force of the stator assembly 20 increases, so as to reduce the back electromotive force of the stator assembly 20 .

[0240] When the back electromotive force increases, the magnetic conductive block 13 is moved toward the first position to reduce the magnetic field strength of the rotor assembly 10. Under the same other conditions, the back electromotive force will decrease as the magnetic field strength decreases.

[0241] It should be noted that in the technical solution of the embodiment of the present application, the increase of the back electromotive force of the stator assembly 10 can be determined by monitoring the voltage or current of the stator winding. Specifically, during the operation of the motor, the voltage or current of the stator winding is monitored in real time. The greater the change, the greater the back electromotive force. Alternatively, as mentioned above, the increase of the back electromotive force will cause the stator winding to heat up. Therefore, the temperature of the stator winding can also be monitored. The higher the temperature, the greater the back electromotive force.

[0242] According to the above technical solution, by arranging a movable magnetic conductive block in the rotor assembly of the permanent magnet synchronous motor, when the stator back electromotive force increases under high-speed conditions, the magnetic field strength of the rotor assembly is reduced by moving the magnetic conductive block, which can effectively suppress the back electromotive force of the stator assembly, thereby avoiding the influence of a large back electromotive force on the safe operation of the motor, so that the motor has a higher power factor and efficiency under high-speed conditions, and increases the operating range of the motor.

[0243] In some embodiments, when the magnetic conductive block 13 is located at the first position, the back electromotive force of the stator assembly 20 is zero.

[0244] As mentioned above, when the magnetic conductive block 13 is in the first position, it can completely short-circuit the magnetic flux of the rotor assembly 10, so that the magnetic intensity of the rotor assembly 10 is 0, and the magnetic coupling between the rotor assembly 10 and the stator assembly 20 is completely released, so that the back electromotive force of the stator assembly 20 is 0. Therefore, there will be no risks such as circulating current, heating and vibration.

[0245] The embodiment of the present application also provides a vehicle, including a permanent magnet synchronous motor as described above. In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0246] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0247] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0248] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0249] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0250] The above is only a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A rotor assembly, characterized in that: include: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, and each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft; The magnetic conductive block is configured to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly.

2. The rotor assembly according to claim 1, characterized in that When the magnetic conductive block is located at the first position, one end of the magnetic conductive block close to the permanent magnet slot along the radial direction abuts against the rotor core.

3. The rotor assembly according to claim 2, characterized in that: The permanent magnet slot comprises a first permanent magnet slot and a second permanent magnet slot which are symmetrically arranged about the center line of the D axis; The first permanent magnet slot near one end of the rotating shaft and the second permanent magnet slot near one end of the rotating shaft form a first opening, and the width of the magnetic conductive block along the direction perpendicular to the radial direction is not less than the width of the first opening, so that when the magnetic conductive block is located at the first position, the end surface of the magnetic conductive block near one end of the permanent magnet slot can cover the first opening.

4. The rotor assembly according to claim 3, characterized in that: The rotor core has a recessed portion that is recessed toward the direction close to the permanent magnet slot, the recessed portion is arranged corresponding to the permanent magnet slot, and is located on a side of the permanent magnet slot close to the rotating shaft; The end of the magnetic conductive block close to the permanent magnet slot has a protrusion, the protrusion matches the shape of the recess, and when the magnetic conductive block is located at the first position, the protrusion extends into the recess.

5. The rotor assembly according to claim 4, characterized in that: The protruding portion is an arc-shaped end surface.

6. The rotor assembly according to claim 4, characterized in that: The protrusion includes a first end face and a second end face arranged in a V shape, and an angle formed by the first end face and the second end face is oriented toward an end close to the permanent magnet slot.

7. The rotor assembly according to claim 6, characterized in that An included angle formed by the first end surface and the second end surface is an obtuse angle.

8. The rotor assembly according to any one of claims 5 to 7, characterized in that: The rotor core has a plurality of slide grooves corresponding to the plurality of permanent magnet slots, each of the slide grooves is arranged in a radial direction, a first end of the slide groove in the radial direction is close to the permanent magnet slot, and a second end is arranged at a distance from the rotating shaft of the rotor assembly, and the magnetic conductive block can slide in the slide groove to move between the first position and the second position; The first end of the slide groove has a recessed area, and the recessed area matches the shape of the protruding portion.

9. The rotor assembly according to claim 8, characterized in that The arc angle of the first permanent magnet slot and the second permanent magnet slot close to one end of the rotating shaft is less than or equal to the arc angle of the first permanent magnet slot and the second permanent magnet slot away from one end of the rotating shaft.

10. The rotor assembly according to claim 9, characterized in that The first position is located close to the first permanent magnet slot and the second permanent magnet slot and close to one end of the rotating shaft.

11. The rotor assembly according to claim 10, characterized in that A first magnetic isolation groove and a second magnetic isolation groove are disposed at two ends of the first permanent magnet groove, and a third magnetic isolation groove and a fourth magnetic isolation groove are disposed at two ends of the second permanent magnet groove.

12. The rotor assembly according to claim 11, characterized in that The rotor core also has an internal magnetic bridge arranged corresponding to the permanent magnet slot, and the internal magnetic bridge includes a first internal magnetic bridge and a second internal magnetic bridge. The first internal magnetic bridge is located between the slide slot and the second magnetic isolation slot, and the second internal magnetic bridge is located between the slide slot and the fourth magnetic isolation slot.

13. The rotor assembly according to claim 11, characterized in that The rotor core also has an external magnetic bridge arranged corresponding to the permanent magnet slot, and the external magnetic bridge includes a first external magnetic bridge and a second external magnetic bridge. The first external magnetic bridge is located between the first magnetic isolation slot and the outer edge of the rotor assembly, and the second external magnetic bridge is located between the third magnetic isolation slot and the outer edge of the rotor assembly.

14. The rotor assembly according to claim 13, characterized in that The first magnetic isolation groove and the third magnetic isolation groove penetrate the rotor core in a radial direction.

15. The rotor assembly according to claim 14, characterized in that The rotor assembly also includes a rotor sleeve, which is sleeved on the outer side of the rotor core.

16. The rotor assembly according to claim 15, characterized in that The rotor sleeve is made of carbon fiber or non-magnetic alloy material.

17. The rotor assembly according to claim 3, characterized in that The rotor core includes a core shaft core, a D-axis core and a Q-axis core; Wherein, the core shaft core is a sleeve close to the axis of the rotor core; The D-axis iron core is located between the first permanent magnet slot and the second permanent magnet slot; The Q-axis iron core is located between two adjacent permanent magnet slots.

18. The rotor assembly according to claim 17, characterized in that The core shaft core, the D-axis core and the Q-axis core are integrally formed.

19. The rotor assembly according to claim 17, characterized in that The core shaft core, the D-axis core and the Q-axis core are a combined structure; The D-axis iron core is made of silicon steel material, amorphous material or nanocrystalline material; The Q-axis iron core is made of silicon steel material, amorphous material or nanocrystalline material.

20. The rotor assembly according to claim 19, characterized in that The core shaft core and the Q-axis core are integrally formed, or the Q-axis core and the core shaft core are connected via a dovetail structure.

21. A permanent magnet synchronous motor, comprising a rotor assembly and a stator assembly, characterized in that: The rotor assembly is the rotor assembly according to any one of claims 1-20.

22. A permanent magnet synchronous motor, applied to the power system of urban rail transit vehicles, characterized in that: The vehicle power system includes a plurality of permanent magnet synchronous motors for providing power to the vehicle, the permanent magnet synchronous motors including a rotor assembly and a stator assembly, the rotor assembly including: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, and each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft; The magnetic conductive block is configured as follows: When the vehicle is in a coasting condition, the magnetic conductive block is located at a first position close to the permanent magnet slot, so as to reduce the iron loss of the permanent magnet synchronous motor in the coasting condition; When the vehicle is in a traction condition, the magnetic conductive block is located at a second position away from the permanent magnet slot to increase the air gap magnetic field strength between the rotor assembly and the stator assembly.

23. The permanent magnet synchronous motor according to claim 22, characterized in that: The magnetic conductive block is further configured to: when the speed of the vehicle is greater than a first speed threshold, the magnetic conductive block moves between the first position and the second position to adjust the magnetic field distribution of the rotor assembly and increase the speed regulation range of the permanent magnet synchronous motor; The first speed threshold is related to the rated speed of the permanent magnet synchronous motor.

24. A power system, applied to urban rail transit vehicles, for providing power for the vehicles, characterized in that: The power system comprises a permanent magnet synchronous motor as claimed in claim 22 or 23.

25. An urban rail transit vehicle, characterized in that: The vehicle comprises: a permanent magnet synchronous motor as claimed in claim 22 or 23, or a power system as claimed in claim 24.

26. A permanent magnet synchronous traction motor, applied to the traction system of a locomotive, characterized in that: The permanent magnet synchronous traction motor comprises a rotor assembly and a stator assembly, wherein the rotor assembly comprises: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, and each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft; The magnetic conductive block is configured to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot according to the operating speed of the locomotive, and adjust the magnetic field distribution of the rotor assembly so that the permanent magnet synchronous traction motor can output constant power when driving the locomotive to operate within its operating speed range.

27. The permanent magnet synchronous traction motor according to claim 26, characterized in that: The magnetic conductive block is further configured as: When the speed of the locomotive is greater than a first speed, the magnetic conductive block is located at or close to the first position to reduce the air gap magnetic field strength of the rotor assembly and increase the speed of the permanent magnet synchronous traction motor. The first speed is related to the rated speed of the permanent magnet synchronous traction motor.

28. A traction system, applied to a locomotive, characterized in that: The traction system comprises the permanent magnet synchronous traction motor as claimed in claim 26 or 27.

29. A locomotive, characterized in that: include: A permanent magnet synchronous traction motor as claimed in claim 26 or 27, or a traction system as claimed in claim 28.

30. A power system, applied to a train, characterized in that: The power system includes a plurality of permanent magnet synchronous motors for driving the train, each of the permanent magnet synchronous motors including a rotor assembly and a stator assembly; The rotor assembly comprises: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft, and the magnetic conductive block is used to switch between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; The power system is configured to: when a turn-to-turn short circuit fault occurs in a target permanent magnet synchronous motor among the multiple permanent magnet synchronous motors, switch the magnetic conductive block in the target permanent magnet synchronous motor to the first position to short-circuit the main magnetic flux of the target permanent magnet synchronous motor and take the target permanent magnet synchronous motor out of service.

31. A train, characterized in that: Comprising a power system as claimed in claim 30.

32. A permanent magnet synchronous motor, applied to mobile equipment, characterized in that: The permanent magnet synchronous motor comprises a stator assembly and a rotor assembly, wherein the rotor assembly comprises: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft, and the magnetic conductive block is used to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; The magnetic conductive block is configured to move to the first position or close to the first position when the speed of the mobile equipment is greater than the first speed, so as to improve the efficiency of the permanent magnet synchronous motor under high-speed conditions.

33. A mobile device, characterized in that: Comprising a permanent magnet synchronous motor as described in claim 32.

34. A permanent magnet synchronous motor, characterized in that: The invention comprises a stator assembly and a rotor assembly, wherein the rotor assembly comprises: A rotor core having a plurality of permanent magnet slots uniformly distributed along the circumferential direction; A permanent magnet is disposed in the permanent magnet slot; A plurality of magnetic conductive blocks are arranged corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks is arranged radially on a side of the corresponding permanent magnet slot close to the rotating shaft, and the magnetic conductive block is used to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot to adjust the magnetic field distribution of the rotor assembly; The magnetic conductive block is further configured to move from the second position to the direction close to the first position when the back electromotive force of the stator assembly increases, so as to reduce the back electromotive force of the stator assembly.

35. A vehicle, characterized in that: Comprising a permanent magnet synchronous motor as described in claim 34.

Images