A hybrid permanent magnet memory motor and a multi-stage magnetic modulation pulse injection method

Abstract

The present invention discloses a hybrid permanent magnet memory motor and a multi-stage magnetic modulation pulse injection method, which relate to the technical field of memory motors. The present invention comprises: a stator core, wherein the inner circumference of the stator core is provided with a plurality of stator teeth, and the armature winding is installed between two stator teeth; and a rotor core, wherein the rotor core is sleeved inside the stator core. The Y-type topology structure of the present invention includes two different magnetic circuits, a series type and a parallel type. The high coercive force permanent magnet can provide a stable magnetomotive force, and since the high coercive force permanent magnet is located outside the rotor, it can effectively resist unexpected demagnetization under load conditions; the low coercive force permanent magnet can be bidirectionally magnetized, and most of the magnetic field forms a short circuit inside the rotor when the magnetism is weak, thereby effectively improving the magnetic modulation range. Compared with the traditional d-axis magnetic modulation, the magnetic modulation method only requires a smaller pulse current to achieve the same magnetic modulation effect as the traditional structure.

Description

Technical Field

[0001] The present invention relates to the technical field of memory motors, and in particular to a hybrid permanent magnet memory motor and a multi-segment magnetic modulation pulse injection method. Background Art

[0002] With the development of electric vehicles, permanent magnet synchronous motors (PMSMs) have attracted widespread attention due to their high power density and ease of control. However, because their magnetic force is provided by fixed permanent magnets, their air gap magnetic field is essentially constant, resulting in a limited speed regulation range. Furthermore, when the motor operates in the high-speed range, a continuous negative d-axis current is required to prevent damage to power electronic components caused by excessive back electromotive force. This, however, increases copper losses in the motor, affecting its efficiency.

[0003] German scholar Ostovic first proposed the concept of "memory motor" in 2001. This motor uses low-coercive force permanent magnets (aluminum nickel cobalt) as permanent magnets, and generates d-axis pulses through the armature winding to change the magnetization state of the permanent magnet, thereby adjusting the air gap magnetic field. The hybrid permanent magnet memory motor uses high-coercive force permanent magnets (neodymium iron boron) and low-coercive force permanent magnets to form a circuit to achieve the purpose of improving power density and at the same time increase the anti-demagnetization ability of aluminum nickel cobalt. However, at the same time, due to the clamping effect of neodymium iron boron on the direction of the magnetic field, the demagnetization of aluminum nickel cobalt becomes more difficult, and the magnetization level of aluminum nickel cobalt is difficult to adjust to the opposite direction of neodymium iron boron, and the magnetic adjustment range of the motor is narrow. For this reason, we propose a hybrid permanent magnet memory motor and a multi-segment magnetic adjustment pulse injection method. Summary of the Invention

[0004] The object of the present invention is to provide a hybrid permanent magnet memory motor and a multi-segment magnetic modulation pulse injection method, which can effectively improve the magnetic modulation range.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a hybrid permanent magnet memory motor, comprising:

[0006] A stator core, wherein a plurality of stator teeth are provided on the inner circumference of the stator core, and an armature winding is installed between two stator teeth;

[0007] a rotor core, wherein the rotor core is sleeved within the stator core, and a plurality of permanent magnet assemblies are mounted on the rotor core, wherein the permanent magnet assemblies include a high-coercive force permanent magnet, a first low-coercive force permanent magnet, and a second low-coercive force permanent magnet, wherein the three permanent magnets are arranged in a "Y" shape, with the high-coercive force permanent magnet being close to the outer side of the rotor core and arranged radially, and the first low-coercive force permanent magnet and the second low-coercive force permanent magnet being close to the inner side of the rotor core and arranged circumferentially;

[0008] A long magnetic barrier is provided on the rotor core and is used to isolate the magnetic path of each pair of permanent magnet assemblies;

[0009] A short magnetic barrier is provided on the rotor core and is used to isolate the magnetic paths of a first low-coercive force permanent magnet and a second low-coercive force permanent magnet in a permanent magnet assembly.

[0010] Furthermore, the high coercive force permanent magnet is a neodymium iron boron magnet, and the first low coercive force permanent magnet and the second low coercive force permanent magnet are alnico magnets.

[0011] Furthermore, the long magnetic barriers and the short magnetic barriers are both made of non-magnetic conductive materials.

[0012] Furthermore, the long magnetic barriers and the short magnetic barriers are both made of aluminum, copper or steel.

[0013] Furthermore, between the two adjacent permanent magnet assemblies, the magnetic poles of the high-coercive force permanent magnet are opposite, and their magnetization directions do not change during the magnetization process. The first low-coercive force permanent magnet and the second low-coercive force permanent magnet do not have fixed magnetization directions, and their magnetization directions change with the magnetization pulse.

[0014] Furthermore, a rotating shaft is mounted on the rotor core, and the center of the rotating shaft coincides with the center of the rotor core.

[0015] Furthermore, the thickness ratio between the high-coercive force permanent magnet and the low-coercive force permanent magnet is 4:3, and the angle between the first low-coercive force permanent magnet and the second low-coercive force permanent magnet is 110°.

[0016] Furthermore, the long magnetic barrier is arranged between adjacent permanent magnet assemblies, the middle part of the long magnetic barrier is rectangular, and the two ends are semicircular. The long magnetic barrier is perpendicular to the first and second low coercive force permanent magnets, and the distance between the two is ≤2mm. The distance between the bottom end of the long magnetic barrier and the rotating shaft is ≤4mm.

[0017] Furthermore, one end of the short magnetic barrier is arranged at the center of the permanent magnet assembly, and the other end is arranged close to the center, and the other end is semicircular.

[0018] According to one aspect of the present invention, the present invention provides a multi-segment magnetic modulation pulse injection method applied to the hybrid permanent magnet memory motor, comprising:

[0019] Injecting a first pulse, where the first pulse injection position is the positive d-positive q-axis, the current pulse is injected from the positive d-positive q-axis position, and flows out from the negative d-negative q-axis position, thereby completing the magnetization of the first low-coercive-force permanent magnet;

[0020] The second pulse is injected at the positive d and negative q axes. The current pulse is injected from the positive d and negative q axes and flows out from the negative d and positive q axes, thereby completing the magnetization of the second low coercive force permanent magnet.

[0021] The present invention has at least the following beneficial effects:

[0022] 1. The Y-type topology structure of the present invention includes two different magnetic circuits: series and parallel. Among them, the high-coercive force permanent magnet can provide a stable magnetomotive force. Since the high-coercive force permanent magnet is located on the outside of the rotor, it can effectively resist unexpected demagnetization under load conditions. The low-coercive force permanent magnet can be magnetized in both directions. When the magnetic field is weakened, most of the magnetic field forms a short circuit inside the rotor, thereby effectively improving the magnetic adjustment range.

[0023] 2. The multi-stage magnetic modulation pulse injection method described in the present invention uses two successive pulses to achieve magnetic modulation of the first and second low-coercive force permanent magnets. Compared with traditional d-axis pulse magnetic modulation, the required pulse current amplitude is more than half smaller, effectively reducing the required capacity of the inverter equipment. At the same time, this method can draw on traditional vector control technology and is easy to implement in principle.

[0024] 3. The present invention can repeatedly magnetize the first and second low-coercive-force permanent magnets online, has good magnetic adjustment characteristics, and can effectively avoid excitation copper loss.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of the hybrid permanent magnet memory motor of the present invention;

[0027] Figure 2a Schematic diagram of the first segment of magnetic modulation pulse in the multi-segment magnetic modulation pulse injection method;

[0028] Figure 2b Schematic diagram of the second segment of magnetic modulation pulse in the multi-segment magnetic modulation pulse injection method;

[0029] Figure 3 This is a schematic diagram of the internal magnetic field of the motor in the magnetization operation mode;

[0030] Figure 4 This is a schematic diagram of the internal magnetic field of the motor in the field-weakening operation mode.

[0031] Reference numerals:

[0032] 1. Stator core; 2. Armature winding; 3. Rotor core; 4. Rotating shaft; 5. Permanent magnet assembly; 51. High-coercivity permanent magnet; 52. First low-coercivity permanent magnet; 53. Second low-coercivity permanent magnet; 6. Long magnetic barrier; 7. Short magnetic barrier; 8. Stator teeth. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0034] Example 1:

[0035] The technical solution provided by the present invention can adjust the working point of the low-coercive force permanent magnet through current pulses, thereby adjusting the air gap magnetic flux density.

[0036] See also Figure 1 The present invention provides a technical solution: a hybrid permanent magnet memory motor, comprising: a stator core 1, a plurality of stator teeth 8 are provided on the inner circumference of the stator core 1, and an armature winding 2 is installed between two stator teeth 8;

[0037] The rotor core 3 is sleeved within the stator core 1. A plurality of permanent magnet assemblies 5 are mounted on the rotor core 3. The permanent magnet assembly 5 includes a high-coercive-force permanent magnet 51, a first low-coercive-force permanent magnet 52, and a second low-coercive-force permanent magnet 53. The three permanent magnets are arranged in a Y-shape, with the high-coercive-force permanent magnet 51 being radially disposed near the outside of the rotor core 3, and the first low-coercive-force permanent magnet 52 and the second low-coercive-force permanent magnet 53 being circumferentially disposed near the inside of the rotor core 3.

[0038] Long magnetic barriers 6 are provided on the rotor core 3 to isolate the magnetic paths of each pair of permanent magnet assemblies 5;

[0039] The short magnetic barrier 7 is provided on the rotor core 3 and is used to isolate the magnetic circuits of the first low-coercive-force permanent magnet 52 and the second low-coercive-force permanent magnet 53 in one permanent magnet assembly 5 .

[0040] A rotating shaft 4 is mounted on the rotor core 3 , and the center of the rotating shaft 4 coincides with the center of the rotor core 3 .

[0041] It should be noted that the stator core 1, stator teeth 8 and armature winding 2 constitute the stator; the rotor core 3, several permanent magnet assemblies 5, rotating shaft 4, long magnetic barriers 6 and short magnetic barriers 7 constitute the rotor, and the rotor and stator are rotationally connected.

[0042] It should be noted that in one magnetic pole, the three permanent magnets are arranged in a "Y" shape, and the high coercive force permanent magnet 51 is a neodymium iron boron magnet; the first low coercive force permanent magnet 52 and the second low coercive force permanent magnet 53 are distributed on both sides of the end of the high coercive force permanent magnet 51, and the first low coercive force permanent magnet 52 and the second low coercive force permanent magnet 53 are aluminum nickel cobalt magnets.

[0043] The first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 are connected in series to form a series magnetic circuit, and the high-coercive force permanent magnet 51 and the low-coercive force permanent magnet are connected in parallel to form a parallel magnetic circuit.

[0044] Furthermore, between two adjacent permanent magnet assemblies 5, the magnetic poles of the high-coercive force permanent magnet 51 are opposite, and its magnetization direction does not change during the magnetization process. The first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 do not have a fixed magnetization direction, and their magnetization directions change with the magnetization pulse. The thickness ratio of the high-coercive force permanent magnet 51 and the low-coercive force permanent magnet is 4:3, and the angle between the first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 is 110°.

[0045] On the other hand, the long magnetic barrier 6 and the short magnetic barrier 7 are both made of non-magnetic materials. According to the technical solution of this application, the long magnetic barrier 6 and the short magnetic barrier 7 are made of aluminum, copper or steel. The middle part of the long magnetic barrier 6 is rectangular and the two ends are semicircular. The long magnetic barrier 6 is arranged between adjacent permanent magnet assemblies 5 to separate the adjacent permanent magnet assemblies 5. It is perpendicular to the first and second low coercive force permanent magnets 53 and the distance between them is no more than 2 mm. The bottom end of the long magnetic barrier 6 is no more than 4 mm away from the rotating shaft 4.

[0046] One end of the short magnetic barrier 7 is located in the center of the permanent magnet assembly 5 and the other end is semicircular, dividing the magnetic path of the first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53. The distance between the end of the short magnetic barrier 7 and the rotating shaft 4 is no more than 4 mm.

[0047] Example 2:

[0048] Combine Figure 2a 、 2b As shown, the present invention provides a multi-stage magnetic modulation pulse injection method applied to the hybrid permanent magnet memory motor, and the operating principle is as follows:

[0049] The first pulse is injected at the positive d-positive q-axis. The current pulse is injected from the positive d-positive q-axis position and flows out from the negative d-negative q-axis position, thereby completing the magnetization of the first low-coercive-force permanent magnet 52. Due to the blocking effect of the magnetic barrier in the rotor magnetic circuit, the magnetic flux hardly passes through the second low-coercive-force permanent magnet 53, so the magnetization state of the second low-coercive-force permanent magnet 53 does not change.

[0050] A second pulse is injected, and the injection position of the second pulse is the positive d and negative q axis. The current pulse is injected from the positive d and negative q axis position and flows out from the negative d and positive q axis position to complete the magnetization of the second low-coercive force permanent magnet 53. Due to the blocking effect of the magnetic barrier, the magnetic potential does not flow through the first low-coercive force permanent magnet 52, so the working point of the magnetized second low-coercive force permanent magnet 53 will not be changed again. The injection amplitude of the second pulse is close to the amplitude of the first pulse to ensure that in one pole, the first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 are at the same working point after the pulse injection is completed.

[0051] Example 3:

[0052] Combine Figure 3 and Figure 4 As shown, the online magnetic adjustment operation principle of a hybrid permanent magnet memory motor disclosed in the present invention is as follows:

[0053] The first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 have the characteristic of nonlinear BH curve. Under the action of a large external magnetic field, they will be magnetized or demagnetized. When the magnetic field is removed, the permanent magnet can "memorize" the magnetization level and thus work at a new working point. When the motor is in the magnetization operation mode, the first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53 are in the demagnetized state, and most of the magnetic flux of the high-coercive force permanent magnet 51 flows out from the N pole, passes through the air gap, reaches the stator tooth 8, and then passes through the stator yoke and returns. To the S pole of the permanent magnet; when the motor is in the weak magnetic operation mode, the first low coercive force permanent magnet 52 and the second low coercive force permanent magnet 53 are in the magnetized state, and the high coercive force permanent magnet 51 is equivalent to being "short-circuited". Most of its magnetic flux flows through the first low coercive force permanent magnet 52 and the second low coercive force permanent magnet 53 and circulates inside the rotor. At this time, only a small part of the magnetic flux flows through the air gap. By injecting the position of the current pulse, the first low coercive force permanent magnet 52 and the second low coercive force permanent magnet 53 are charged and demagnetized, thereby realizing the online magnetic adjustment of the motor.

[0054] In summary, the technical solution provided by the present invention includes two different magnetic circuits, series and parallel. Among them, the high coercive force permanent magnet 51 can provide a stable magnetomotive force, and because the high coercive force permanent magnet 51 is located on the outside of the rotor, it can effectively resist unexpected demagnetization under load conditions; and the first low coercive force permanent magnet 52 can be bidirectionally magnetized, and most of the magnetic field forms a short circuit inside the rotor when the magnetism is weak, thereby effectively improving the magnetic adjustment range.

[0055] At the same time, the multi-stage magnetic modulation pulse injection method provided by the present invention uses two successive pulses to achieve magnetic modulation of the first low-coercive force permanent magnet 52 and the second low-coercive force permanent magnet 53. Compared with the traditional d-axis pulse magnetic modulation, the required pulse current amplitude is more than half smaller, effectively reducing the required capacity of the inverter equipment.

[0056] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0057] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on", "installed on", "fixed on" or "set on" another element, it can be directly on the other element or there can be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a central element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0059] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Claims

1. A hybrid permanent magnet memory motor, characterized in that: include; A stator core (1), wherein a plurality of stator teeth (8) are provided on the inner circumference of the stator core (1), and an armature winding (2) is installed between two stator teeth (8); A rotor core (3), wherein the rotor core (3) is sleeved within the stator core (1), and a plurality of permanent magnet assemblies (5) are mounted on the rotor core (3), wherein the permanent magnet assemblies (5) include a high-coercive force permanent magnet (5.1), a first low-coercive force permanent magnet (5.2), and a second low-coercive force permanent magnet (5.3), wherein the three permanent magnets are arranged in a "Y" shape, and the high-coercive force permanent magnet (5.1) is close to the outside of the rotor core (3) and is arranged radially, while the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) are close to the inside of the rotor core (3) and are arranged circumferentially; A long magnetic barrier (6), the long magnetic barrier (6) being provided on the rotor core (3) and being used to isolate the magnetic paths of adjacent permanent magnet assemblies (5); A short magnetic barrier (7), the short magnetic barrier (7) being provided on the rotor core (3) and being used for isolating the magnetic circuits of a first low-coercive force permanent magnet (5.2) and a second low-coercive force permanent magnet (5.3) in a permanent magnet assembly (5); The long magnetic barrier (6) is arranged between adjacent permanent magnet assemblies (5), the middle part of the long magnetic barrier (6) is rectangular, and the two ends are semicircular. The long magnetic barrier (6) and the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) adjacent to it are all perpendicular to each other, and the distance between the long magnetic barrier (6) and the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) adjacent to it is less than or equal to 2 mm, and the distance between the bottom end of the long magnetic barrier (6) and the rotating shaft (4) is less than or equal to 4 mm.

2. The hybrid permanent magnet memory motor according to claim 1, characterized in that: The high-coercive force permanent magnet (5.1) is a neodymium iron boron magnet, and the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) are aluminum nickel cobalt magnets.

3. The hybrid permanent magnet memory motor according to claim 2, characterized in that: The long magnetic barrier (6) and the short magnetic barrier (7) are both made of non-magnetic conductive materials.

4. The hybrid permanent magnet memory motor according to claim 3, characterized in that: The long magnetic barrier (6) and the short magnetic barrier (7) are both made of any one of aluminum, copper or steel.

5. The hybrid permanent magnet memory motor according to claim 2, characterized in that: Between two adjacent permanent magnet assemblies (5), the magnetic poles of the high-coercive force permanent magnets (5.1) are opposite, and their magnetization directions do not change during the magnetization process; the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) do not have fixed magnetization directions, and their magnetization directions change with the magnetization pulse.

6. The hybrid permanent magnet memory motor according to claim 5, characterized in that: A rotating shaft (4) is mounted on the rotor core (3), and the center of the rotating shaft (4) coincides with the center of the rotor core (3).

7. The hybrid permanent magnet memory motor according to claim 5, characterized in that: The thickness ratio between the high-coercive force permanent magnet (5.1) and the low-coercive force permanent magnet is 4:3, and the angle between the first low-coercive force permanent magnet (5.2) and the second low-coercive force permanent magnet (5.3) in the same permanent magnet assembly (5) is 110°.

8. The hybrid permanent magnet memory motor according to claim 1, characterized in that: One end of the short magnetic barrier (7) is arranged at the center of the permanent magnet assembly (5), and the other end is arranged close to the center side, and the other end is semicircular.

9. A multi-segment magnetic modulation pulse injection method applied to a hybrid permanent magnet memory motor according to any one of claims 1 to 8, characterized in that: include: Injecting a first pulse, the first pulse injection position is the positive d positive q axis, the current pulse is injected from the positive d positive q axis position, and flows out from the negative d negative q axis position, thereby completing the magnetization of the first low coercive force permanent magnet (5.2); The second pulse is injected at the positive d and negative q axes. The current pulse is injected from the positive d and negative q axes and flows out from the negative d and positive q axes, thereby completing the magnetization of the second low coercive force permanent magnet (5.3).

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