Motor rotor and motor

Abstract

The utility model provides a motor rotor and a motor, and relates to the technical field of motors. The motor rotor comprises a rotor core and a multi-layer magnetic steel structure embedded in the rotor core, the multi-layer magnetic steel structure comprises at least one group of high-coercivity magnetic steel and low-coercivity magnetic steel, and the coercivity of the high-coercivity magnetic steel is larger than that of the low-coercivity magnetic steel. The high-coercivity magnetic steel and the low-coercivity magnetic steel form a composite magnetic circuit structure which is partially connected in series and partially connected in parallel on a magnetic circuit, and the magnetization state of the low-coercivity magnetic steel is adjustable; the composite magnetic circuit structure comprises a series magnetic circuit and a parallel magnetic circuit, the series magnetic circuit comprises a magnetic circuit formed by sequentially arranging high-coercivity magnetic steel and low-coercivity magnetic steel in the magnetic flux direction, and the parallel magnetic circuit comprises a first magnetic circuit formed by the high-coercivity magnetic steel in the magnetic flux direction and a second magnetic circuit formed by the low-coercivity magnetic steel in the magnetic flux direction. The first magnetic circuit and the second magnetic circuit are arranged in parallel. According to the utility model, the overall efficiency and the wide speed range performance can be obviously improved, and the efficiency optimization of all working conditions is realized.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and more specifically, to a motor rotor and a motor. Background Technology

[0002] With the rapid development of the new energy vehicle industry, drive systems are evolving towards higher efficiency, higher power density, and wider speed range operation. To achieve higher vehicle range and power performance, electric drive systems generally adopt high-voltage platforms and high-speed motor designs. High voltage can effectively reduce transmission current and wire losses, while high speed helps to reduce motor size and increase power density. However, in engineering practice, balancing the efficiency of the motor under high torque and high-speed operating conditions has become a key technical bottleneck restricting the improvement of system performance.

[0003] Existing permanent magnet synchronous motors typically employ a high magnetic load design to ensure output capacity under low-speed, high-torque conditions. However, during high-speed operation, the magnetic field alternation frequency increases dramatically, resulting in a significant increase in iron losses. Especially when frequently switching between low-speed climbing and high-speed cruising, the motor struggles to maintain its efficient operating range, leading to high energy consumption. Utility Model Content

[0004] The problem this invention addresses is how to improve motor efficiency.

[0005] To solve the above problems, this utility model provides a motor rotor and a motor.

[0006] In a first aspect, this utility model provides a motor rotor, including a rotor core and a multi-layer magnet structure embedded in the rotor core. The multi-layer magnet structure includes at least one set of high-coercivity magnets and low-coercivity magnets. The coercivity of the high-coercivity magnets is greater than that of the low-coercivity magnets. The high-coercivity magnets and the low-coercivity magnets form a composite magnetic circuit structure that is partially connected in series and partially in parallel on the magnetic circuit. The magnetization state of the low-coercivity magnets is adjustable. The composite magnetic circuit structure includes a series magnetic circuit and a parallel magnetic circuit. The series magnetic circuit includes a magnetic circuit formed by the high-coercivity magnets and the low-coercivity magnets arranged sequentially along the magnetic flux direction. The parallel magnetic circuit includes a first magnetic circuit formed by the high-coercivity magnets along the magnetic flux direction and a second magnetic circuit formed by the low-coercivity magnets along the magnetic flux direction. The first magnetic circuit and the second magnetic circuit are arranged side by side.

[0007] Optionally, the high coercivity magnets are arranged in the inner layer region of the rotor core, and the low coercivity magnets are arranged in the outer layer region of the rotor core. The high coercivity magnets and the low coercivity magnets are sequentially distributed along the radial direction of the rotor core to form the multilayer magnet structure.

[0008] Optionally, the rotor core is provided with a plurality of radially arranged magnet slots, and the high coercivity magnets and the low coercivity magnets are sequentially embedded in the plurality of magnet slots.

[0009] Optionally, in the series magnetic circuit, the magnetic flux passes sequentially through the high coercivity magnet, the low coercivity magnet, and the stator air gap.

[0010] Optionally, in the parallel magnetic circuit, the magnetic flux flows to the stator air gap via the high coercivity magnet or the low coercivity magnet.

[0011] Optionally, the series magnetic circuit and the parallel magnetic circuit are adjacent to each other in the rotor radial direction and / or circumferential direction to form a continuous magnetic circuit interface, which allows magnetic flux to be split, merged or transferred between the series magnetic circuit and the parallel magnetic circuit.

[0012] Optionally, the low coercivity magnet accounts for 40% to 80% of the total amount of magnets in the multilayer magnet structure.

[0013] Secondly, this utility model provides an electric motor, including the motor rotor described in the first aspect, wherein the magnetization state of the low coercivity magnets in the motor rotor is configured to be adjusted by a motor controller.

[0014] Optionally, the motor further includes a stator core, which is disposed on the outer periphery of the rotor core of the motor rotor, and the stator core is used to form a main magnetic circuit with the multilayer magnet structure embedded in the rotor core.

[0015] Optionally, the motor further includes a motor winding disposed in a slot of the stator core, the motor winding being used to connect to the motor controller.

[0016] The beneficial effects of the motor rotor of this utility model are as follows: by setting a multi-layer magnetic steel structure including high coercivity magnets and low coercivity magnets in the rotor core, and forming a composite magnetic circuit structure with partial series and partial parallel connections in the magnetic circuit, the rotor magnetic field can be adjusted in real time according to the working conditions. Compared with the traditional fixed flux permanent magnet rotor, this structure can provide higher torque at low speeds and weaken the magnetic flux by demagnetizing at high speeds, thereby significantly improving the overall efficiency and wide speed range performance, and achieving full-condition efficiency optimization. Attached Figure Description

[0017] Figure 1 This is a topological schematic diagram of the motor according to an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of the magnetization state according to an embodiment of the present invention;

[0019] Figure 3This is a composite efficiency map of an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the series magnetic circuit according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the parallel magnetic circuit according to an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the continuous magnetic circuit interface of an embodiment of the present invention;

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-Rotor core, 2-High coercivity magnet, 3-Low coercivity magnet, 4-Motor winding, 5-Stator core. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Although some embodiments of this utility model are shown in the drawings, it should be understood that this utility model can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this utility model. It should be understood that the drawings and embodiments of this utility model are for illustrative purposes only and are not intended to limit the scope of protection of this utility model.

[0026] It should be understood that the steps described in the method embodiments of this utility model may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this utility model is not limited in this respect.

[0027] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this utility model are only used to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0028] It should be noted that the terms "one" and "multiple" used in this utility model are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0029] The names of the messages or information exchanged between the multiple devices in this embodiment of the invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0030] like Figure 1 As shown in the figure, an embodiment of the present invention provides a motor rotor, including a rotor core 1 and a multi-layer magnet structure embedded in the rotor core 1. The multi-layer magnet structure includes at least one set of high coercivity magnets 2 and low coercivity magnets 3. The coercivity of the high coercivity magnets 2 is greater than that of the low coercivity magnets 3. The high coercivity magnets 2 and the low coercivity magnets 3 form a composite magnetic circuit structure with partial series connection and partial parallel connection in the magnetic circuit. The magnetization state of the low coercivity magnets 3 is adjustable. The composite magnetic circuit structure includes a series magnetic circuit and a parallel magnetic circuit. The series magnetic circuit includes a magnetic circuit formed by the high coercivity magnets 2 and the low coercivity magnets 3 arranged sequentially along the magnetic flux direction. The parallel magnetic circuit includes a first magnetic circuit formed by the high coercivity magnets 2 along the magnetic flux direction and a second magnetic circuit formed by the low coercivity magnets 3 along the magnetic flux direction. The first magnetic circuit and the second magnetic circuit are arranged side by side.

[0031] Specifically, the motor rotor includes a rotor core 1 and a multi-layered magnet structure embedded within the rotor core 1. The multi-layered magnet structure consists of at least one set of high-coercivity magnets 2 and low-coercivity magnets 3. The two types of magnets form a composite magnetic circuit structure with partial series and partial parallel connections in the magnetic circuit. The composite magnetic circuit structure includes two parts: a series magnetic circuit and a parallel magnetic circuit. The series magnetic circuit includes a magnetic circuit formed by the high-coercivity magnets 2 and low-coercivity magnets 3 arranged sequentially along the magnetic flux direction. The parallel magnetic circuit includes a magnetic circuit formed by the high-coercivity magnets 2 and low-coercivity magnets 3 arranged sequentially along the magnetic flux direction. A first magnetic circuit is formed along the direction of magnetic flux, and a second magnetic circuit is formed along the direction of magnetic flux by the low-coercivity magnet 3. The first and second magnetic circuits are arranged side by side. The two magnetic circuits, series and parallel, together constitute a variable magnetic flux path, enabling the rotor to automatically distribute magnetic flux under different operating conditions, balancing high torque and high efficiency. Among them, the high-coercivity magnet 2 can be made of neodymium iron boron (NdFeB) and is used to provide the main magnetic flux. It has strong anti-demagnetization ability and stable magnetic field, but cannot be adjusted by pulse current. Its coercivity is usually greater than 800. The low coercivity magnet 3, with a coercivity of less than 200 kA / m, can be made of AlNiCo, SmCo, or cerium-containing rare earth magnets. Its magnetization or demagnetization can be achieved through current pulses output by the motor controller, thereby adjusting the magnetization state of the low coercivity magnet 3. This allows the rotor to change the magnetic field strength in real time according to operating conditions during operation, achieving optimized efficiency across all operating conditions. For example, when the motor is under low speed or high load conditions, the motor... When the controller does not apply a demagnetizing pulse, the low-coercivity magnet 3 is in a saturated magnetization state, forming a superimposed magnetomotive force with the high-coercivity magnet 2. At this time, the magnetic flux density in the rotor air gap increases, and the output torque is significantly enhanced. However, when the motor is running at high speed, the controller applies a short-duration D-axis demagnetizing pulse current to the rotor, with a pulse width of about 10ms and a peak current of 1.5 times the rated current. The magnetization direction of the low-coercivity magnet is partially reversed, the magnetic flux density decreases, and the back electromotive force decreases accordingly. The system can extend the speed range of the weakened magnetic region to the original 1.More than 4 times; Since the low coercivity magnet 3 can maintain a new magnetic flux state after demagnetization, it does not need to be continuously powered to maintain it. Therefore, compared with the traditional field weakening control, it can save about 5% to 8% of the additional copper loss. When the motor speed drops again, the motor controller outputs a reverse pulse to achieve remagnetization. The response time of the entire magnetic flux adjustment process is less than 50ms, which meets the dynamic requirements of rapid acceleration and braking energy recovery of new energy vehicles. Correspondingly, the motor controller can adopt a vector control algorithm to monitor the speed and load current in real time and dynamically select the magnetic flux mode according to the operating status: (1) Full Magnetic mode (low speed / start): The motor controller does not apply pulses, the low coercivity magnet 3 remains magnetized, outputs high magnetomotive force, and achieves maximum torque; (2) Weakening mode (high speed / cruising): The motor controller applies one or more demagnetizing pulses to partially demagnetize the low coercivity magnet 3, reduce back electromotive force, and improve high-speed efficiency; (3) Remagnetizing mode (braking / climbing): The motor controller applies reverse magnetizing pulses to restore magnetization intensity and achieve rapid torque response; No additional sensors are required, and closed-loop adaptive magnetic flux adjustment can be achieved solely based on current feedback.

[0032] To verify the effectiveness of this invention, a 60kW prototype was used for testing. The test results are as follows: at a rated speed of 4000rpm, the motor efficiency reached 97.2%; in the high-speed range (e.g., 18000rpm), it still maintained an efficiency of over 92%, which is about 4.5% higher than the comparison prototype; the field weakening extension multiple reached 1.48 times, and the upper speed limit increased from 18000rpm to 26700rpm; the torque fluctuation rate decreased from 3.6% in the prototype to 1.9%, and the overall machine operation was more stable. Furthermore, the overall system energy efficiency under the vehicle's WLTC cycle is improved by approximately 6.8%, and the equivalent power consumption per 100 kilometers is reduced by approximately 0.7 kWh. Therefore, this embodiment can significantly improve the energy efficiency and dynamic performance of the electric drive system without increasing hardware complexity. In addition to new energy vehicle drive motors, the motor rotor of this embodiment can also be applied to electric compressor systems (improving compression efficiency through high-speed weak magnetic field operation mode), aerospace electric propulsion systems (maintaining a stable magnetic field at high speeds and improving power density), and industrial servo motors (achieving both high response and high efficiency in multi-condition control). Correspondingly, the low coercivity magnet 3 can also be replaced with cerium magnets or samarium cobalt composite magnets to adapt to higher temperature environments. The magnetic circuit structure can also be designed as a V-shaped or multi-pole staggered layout according to requirements to enhance magnetic flux linkage and heat dissipation performance.

[0033] Among them, combined Figure 2 and Figure 3As shown, the fully magnetized state is the motor's highest torque state, where it is 100% magnetized. When the motor is operating at high speed, the back electromotive force (EMF) increases with the speed. When the back EMF exceeds the motor's limit, the controller sends an Iq pulse current pointing towards the rotor center. The pulse duration is 5ms-10ms, and the pulse current magnitude is approximately 1.5 times or more of the motor's peak current. The current magnitude is related to the coercivity performance of the low-coercivity magnet and the required field weakening amount, and so on. Settings can be configured as follows: Figure 2 Different magnetization states are shown to obtain the optimal efficiency range, as shown in the figure. Figure 3 As shown.

[0034] Among them, the rotor core 1 can adopt a laminated structure, which is made of low-loss silicon steel sheets to reduce eddy current losses at high frequencies; in addition, heat conduction channels can be set on the rotor surface to introduce the air gap cooling airflow generated by the stator into the rotor cavity.

[0035] In this embodiment, by setting a multi-layered magnetic steel structure including high-coercivity magnets and low-coercivity magnets in the rotor core, and forming a composite magnetic circuit structure with partial series and partial parallel connections on the magnetic circuit, the rotor magnetic field can be adjusted in real time according to the operating conditions. Compared with traditional fixed flux permanent magnet rotors, this structure can provide higher torque at low speeds and weaken the magnetic flux by demagnetizing at high speeds, thereby significantly improving the overall efficiency and wide speed range performance, and achieving full-condition efficiency optimization.

[0036] Optionally, the high coercivity magnet 2 is arranged in the inner layer region of the rotor core 1, and the low coercivity magnet 3 is arranged in the outer layer region of the rotor core 1. The high coercivity magnet 2 and the low coercivity magnet 3 are sequentially distributed along the radial direction of the rotor core 1 to form the multilayer magnet structure.

[0037] Specifically, high coercivity magnets 2 are disposed in the inner layer region of rotor core 1 to provide a stable main magnetic field, while low coercivity magnets 3 are disposed in the outer layer region of rotor core 1 to adjust the magnetic field strength. The high coercivity magnets 2 and low coercivity magnets 3 are distributed sequentially along the radial direction of rotor core 1 to form a multi-layer magnet structure. The radial layer design can expand the adjustable magnetic flux range while ensuring the overall magnetic flux stability and improve the field weakening capability during high-speed operation.

[0038] In this optional embodiment, by arranging high coercivity magnets in the inner layer of the rotor core and low coercivity magnets in the outer layer, forming a multi-layer structure in the radial direction, the high coercivity magnets can provide a stable main magnetic field, while the low coercivity magnets can achieve magnetic flux adjustment in the outer layer. This effectively separates the stable magnetic field source from the controllable magnetic field source, taking into account both magnetic flux stability and adjustment flexibility, and improving the thermal stability and magnetic field response speed of the motor.

[0039] Optionally, the rotor core 1 is provided with a plurality of radially arranged magnet slots, and the high coercivity magnet 2 and the low coercivity magnet 3 are sequentially embedded in the plurality of magnet slots.

[0040] Specifically, the rotor core 1 has several radially arranged magnet slots. Each magnet slot contains a high-coercivity magnet 2 and a low-coercivity magnet 3. Each magnet can be fixed in the magnet slot by an insulating layer. The adhesive layer serves both as insulation and to enhance mechanical strength. If a high thermal conductivity insulating adhesive layer is used, the temperature gradient of the magnet can be significantly reduced. Through thermo-magnetic coupling simulation, it can be seen that when the motor speed is 18000 rpm and the ambient temperature is 80℃, the temperature rise of the low-coercivity magnet does not exceed 45℃ and the magnetic flux attenuation is less than 2%, which fully meets the vehicle service life requirements. This structure also avoids the risk of mechanical detachment of the magnet due to centrifugal force, ensuring long-term reliable operation. The number of magnet slots corresponds to the number of rotor poles and can adopt V-shaped, straight slot, or arc-shaped slot structures to optimize the magnetic flux distribution and mechanical strength balance.

[0041] During the manufacturing process, multiple radial magnet slots can be machined on the rotor core 1, with the slot width controlled within ±0.05mm. High coercivity magnets 2 and low coercivity magnets 3 are fixed by vacuum potting process. Epoxy silicone is used as the adhesive layer material. After the adhesive layer is cured, a dynamic balance test is performed, and the eccentricity is controlled within 0.03mm. Subsequently, magnetic isolation end rings and positioning sleeves are installed at both ends of the rotor to reduce end magnetic leakage.

[0042] In this optional embodiment, by setting multiple radial magnet slots in the rotor core and embedding high and low coercivity magnets in each slot in sequence, it is possible to ensure that the magnetic field is uniformly distributed in the circumferential direction, reducing air gap magnetic flux fluctuations and torque pulsations; at the same time, the slot structure helps to mechanically fix the magnets and dissipate heat, improving the structural strength and reliability during high-speed operation.

[0043] Optionally, in the series magnetic circuit, the magnetic flux passes sequentially through the high coercivity magnet 2, the low coercivity magnet 3, and the stator air gap.

[0044] Specifically, in combination Figure 4 As shown, in the series magnetic circuit, the magnetic flux passes through the high coercivity magnet 2, the low coercivity magnet 3 and the stator air gap in sequence to form a continuous magnetic flux path. The high coercivity magnet 2 provides the basic magnetomotive force, and the low coercivity magnet 3 enhances the total magnetomotive force through the magnetization operation, thereby obtaining a higher output torque under low speed and high load conditions. It can significantly improve the driving capability when starting at low speed or climbing, while maintaining stable motor efficiency.

[0045] In this optional embodiment, in the series magnetic circuit, the magnetic flux passes through the high coercivity magnet, the low coercivity magnet and the stator air gap in sequence. The magnetomotive forces of the two types of magnets are superimposed to form a higher magnetic flux density. When the low coercivity magnet is magnetized, the magnetic field strength and output torque under low-speed conditions can be effectively improved, thereby significantly improving the starting performance and climbing ability of the motor.

[0046] Optionally, in the parallel magnetic circuit, the magnetic flux flows to the stator air gap via the high coercivity magnet 2 or the low coercivity magnet 3.

[0047] Specifically, in combination Figure 5 As shown, in the parallel magnetic circuit, the magnetic flux can flow to the stator air gap through either the high coercivity magnet 2 or the low coercivity magnet 3. When the motor is in high-speed operation, a demagnetizing pulse current can be applied to the low coercivity magnet 3 through the motor controller to weaken its magnetomotive force, so that most of the magnetic flux flows through the high coercivity magnet 2, thereby reducing the back electromotive force and iron loss, realizing weak magnetic operation, eliminating the need for continuous weak magnetic current, and significantly improving efficiency in the high-speed range.

[0048] In this optional embodiment, in the parallel magnetic circuit, the magnetic flux can flow to the stator air gap via either the high coercivity magnet path or the low coercivity magnet path. When the low coercivity magnet is demagnetized, the total magnetic flux decreases, the back electromotive force decreases, and the iron loss is significantly reduced. This achieves automatic field weakening operation in the high-speed range, avoids the increase in copper loss caused by traditional field weakening current, and enables the motor to maintain high-efficiency output in the high-speed range.

[0049] Optionally, the series magnetic circuit and the parallel magnetic circuit are adjacent to each other in the rotor radial direction and / or circumferential direction to form a continuous magnetic circuit interface, which allows magnetic flux to be split, merged or transferred between the series magnetic circuit and the parallel magnetic circuit.

[0050] Specifically, in combination Figure 6As shown, the series magnetic circuit and the parallel magnetic circuit are not independently arranged within the rotor core 1, but are adjacent to each other in the radial and / or circumferential directions of the rotor. For example, the two magnetic circuits are directly connected by a continuous magnetic material in a local area of ​​the rotor core 1, thus forming a continuous magnetic circuit interface in structure. At this continuous magnetic circuit interface, the magnetic flux can naturally transition between the series and parallel magnetic circuits. When the low coercivity magnet 3 is in a magnetized state, some of the magnetic flux preferentially flows through the series magnetic circuit path, thereby increasing the magnetomotive force between the high coercivity magnet 2 and the low coercivity magnet 3. The magnetic flux is superimposed along the direction of the magnetic flux, thereby increasing the magnetic flux intensity output by the rotor. At the same time, another part of the magnetic flux can still flow to the stator air gap through the parallel magnetic circuit path to maintain the uniformity of the magnetic field distribution. When the low coercivity magnet 3 is in a demagnetized or partially demagnetized state, the magnetic resistance distribution at the interface of the continuous magnetic circuit changes, causing more magnetic flux to be transferred from the series magnetic circuit to the parallel magnetic circuit, or to be shunted between the two magnetic circuits. In this process, the magnetic flux can be shunted, merged or transferred between the series magnetic circuit and the parallel magnetic circuit without the need for additional mechanical switching structures or electromagnetic switches.

[0051] Among them, flux splitting refers to the simultaneous entry of flux into different magnetic path at the interface of the continuous magnetic path formed by the series magnetic path and the parallel magnetic path, according to the magnetic reluctance distribution of each magnetic path. Flux convergence refers to the magnetic flux propagating along the series magnetic path and the parallel magnetic path respectively converging again in the subsequent magnetic path segment and entering the stator air gap together. Flux transfer refers to the overall change in the distribution ratio of flux between the series magnetic path and the parallel magnetic path when the magnetization state of the low coercivity magnet 3 changes, resulting in a change in the magnetic reluctance condition, thus transforming from one magnetic path to another.

[0052] In this optional embodiment, the continuous magnetic circuit interface formed by the adjacent arrangement allows the magnetic flux distribution relationship between the series magnetic circuit and the parallel magnetic circuit to be dynamically adjusted according to the change of the magnetization state of the low coercivity magnet. This avoids the problem of magnetic flux discontinuity caused by the sudden change in magnetic circuit switching in traditional variable flux motors, which helps to reduce torque pulsation and magnetic noise, and significantly improves the operating efficiency and stability of the motor over a wide speed range.

[0053] Optionally, the low coercivity magnet 3 accounts for 40% to 80% of the multilayer magnet structure.

[0054] Specifically, the proportion of low coercivity magnets 3 in the multi-layer magnet structure is 40% to 80%. When the proportion is less than 40%, the adjustment range is insufficient and the magnetic weakening effect is not obvious. When it exceeds 80%, the magnetic field stability and starting torque will be reduced, the overall magnetic performance will decrease, and the torque density will be insufficient. The proportion range of 40% to 80% can achieve the optimal balance between torque density and magnetic flux adjustment capability, ensuring the optimal efficiency of the motor under all operating conditions in a wide speed range.

[0055] In this optional embodiment, the proportion of low coercivity magnets is limited to 40% to 80%, which ensures sufficient main magnetic field support while guaranteeing the magnetic flux adjustment range, effectively balancing low-speed torque and high-speed efficiency, and preventing excessive demagnetization or magnetic field instability.

[0056] Another embodiment of the present invention provides an electric motor, including a motor rotor, wherein the magnetization state of the low coercivity magnet 3 in the motor rotor is configured to be adjusted by a motor controller.

[0057] Optionally, the motor further includes a stator core 5, which is disposed on the outer periphery of the rotor core 1 of the motor rotor, and the stator core 5 is used to form a main magnetic circuit with the multilayer magnet structure embedded in the rotor core 1.

[0058] Specifically, in combination Figure 1 As shown, the motor also includes a stator core 5, which is disposed on the outer periphery of the rotor core 1 and forms an air gap with the rotor. The stator core 5 adopts a low-loss silicon steel lamination structure to form a closed main magnetic circuit with the rotor magnetic field, thereby ensuring magnetic flux coupling efficiency and reducing high-frequency loss.

[0059] In this optional embodiment, the stator core disposed on the outer periphery of the rotor and the multi-layer magnetic steel structure together form a closed main magnetic circuit, which can effectively improve the magnetic flux coupling efficiency, reduce leakage magnetic loss, and ensure the overall efficiency and thermal stability of the system under high-frequency operation.

[0060] Optionally, the motor further includes a motor winding 4, which is disposed in the slot of the stator core 5 and is used to connect to the motor controller.

[0061] Specifically, in combination Figure 1 As shown, the stator core 5 has a motor winding 4 in its slot. The motor winding 4 is connected to the motor controller. The motor controller can output a D-axis pulse current according to the speed and load status to control the magnetization or demagnetization of the low coercivity magnet 3, thereby realizing the dynamic adjustment of the magnetic flux and enabling the motor to operate in a high-efficiency state in both low-speed and high-speed ranges.

[0062] In this optional embodiment, by arranging motor windings in the stator core slots and connecting them to a motor controller, the motor controller can output pulse current to adjust the magnetization and demagnetization of the low coercivity magnets, thereby achieving online controllability of the magnetic field and optimization of system-level energy consumption.

[0063] Although the present invention has been disclosed above, its protection scope is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the protection scope of the present invention.

Claims

1. A motor rotor, characterized in that, The system includes a rotor core (1) and a multi-layered magnet structure embedded in the rotor core (1). The multi-layered magnet structure includes at least one set of high coercivity magnets (2) and low coercivity magnets (3). The coercivity of the high coercivity magnets (2) is greater than that of the low coercivity magnets (3). The high coercivity magnets (2) and the low coercivity magnets (3) form a composite magnetic circuit structure with partial series connection and partial parallel connection on the magnetic circuit. The magnetization state of the low coercivity magnets (3) is adjustable. The composite magnetic circuit structure includes a series magnetic circuit and a parallel magnetic circuit. The series magnetic circuit includes a magnetic circuit formed by the high coercivity magnets (2) and the low coercivity magnets (3) arranged sequentially along the magnetic flux direction. The parallel magnetic circuit includes a first magnetic circuit formed by the high coercivity magnets (2) along the magnetic flux direction and a second magnetic circuit formed by the low coercivity magnets (3) along the magnetic flux direction. The first magnetic circuit and the second magnetic circuit are arranged side by side.

2. The motor rotor according to claim 1, characterized in that, The high coercivity magnet (2) is arranged in the inner layer region of the rotor core (1), and the low coercivity magnet (3) is arranged in the outer layer region of the rotor core (1). The high coercivity magnet (2) and the low coercivity magnet (3) are distributed sequentially along the radial direction of the rotor core (1) to form the multilayer magnet structure.

3. The motor rotor according to claim 2, characterized in that, The rotor core (1) is provided with a plurality of radially arranged magnet slots, and the high coercivity magnet (2) and the low coercivity magnet (3) are sequentially embedded in the plurality of magnet slots.

4. The motor rotor according to claim 1, characterized in that, In the series magnetic circuit, the magnetic flux passes through the high coercivity magnet (2), the low coercivity magnet (3), and the stator air gap in sequence.

5. The motor rotor according to claim 1, characterized in that, In the parallel magnetic circuit, the magnetic flux flows to the stator air gap via the high coercivity magnet (2) or the low coercivity magnet (3).

6. The motor rotor according to claim 1, characterized in that, The series magnetic circuit and the parallel magnetic circuit are adjacent to each other in the radial and / or circumferential directions of the rotor to form a continuous magnetic circuit interface. The continuous magnetic circuit interface is used to allow magnetic flux to be split, merged or transferred between the series magnetic circuit and the parallel magnetic circuit.

7. The motor rotor according to claim 1, characterized in that, The low coercivity magnet (3) accounts for 40% to 80% of the multilayer magnet structure.

8. An electric motor, characterized in that, The motor rotor includes any one of claims 1 to 7, wherein the magnetization state of the low coercivity magnet (3) in the motor rotor is configured to be adjusted by a motor controller.

9. The motor according to claim 8, characterized in that, It also includes a stator core (5), which is disposed on the outer periphery of the rotor core (1) of the motor rotor, and the stator core (5) is used to form a main magnetic circuit with the multilayer magnet structure embedded in the rotor core (1).

10. The motor according to claim 9, characterized in that, It also includes a motor winding (4), which is disposed in the slot of the stator core (5) and is used to connect to the motor controller.

Images