High energy density combined air-cooled motor system and control method thereof

Abstract

This invention discloses a high-energy-density modular air-cooled motor system and its control method. The core structure comprises three parts: first, a housing assembly, consisting of a coaxial upper cover, a lower cover, and a carbon fiber outer shell forming a motor housing cavity, with a through-type air-cooling channel inside; second, a rotating assembly, including a motor shaft and coaxially mounted fan blades, which can rotate with the shaft to drive airflow to circulate and dissipate heat within the channel; and third, an electromagnetic drive assembly, including a magnetic plate-fixed stator, permanent magnets, and multiple sets of modular electromagnetic units. The modular units can be selectively disassembled and assembled according to load conditions to match different power output requirements. This invention achieves flexible power adaptation for multiple operating conditions through a detachable modular design, reducing iron losses under low loads. Simultaneously, it improves magnetic field utilization through a dual-sided magnetic field coupling structure, and ensures high-load heat dissipation stability with an integrated forced air-cooling architecture. The overall energy density, multi-condition energy efficiency, and operational reliability are significantly improved, making it suitable for load fluctuation scenarios such as tethered drones and heavy-duty servo equipment.

Description

Technical Field

[0001] This invention relates to the field of high energy density motor technology, specifically to a high energy density combined air-cooled motor system and its control method. Background Technology

[0002] In recent years, with the rapid development of tethered drones, heavy-duty industrial servo equipment, and special mobile operation equipment, increasingly higher requirements have been placed on the power density, all-condition energy efficiency, and operational reliability of the supporting drive motors. Permanent magnet brushless motors have become the mainstream power solution for such scenarios due to their high torque density and high efficiency. However, existing products still have several performance shortcomings in practical applications: (1) Poor power adaptation flexibility and poor energy efficiency under all operating conditions Currently, mainstream permanent magnet brushless motors all adopt an integrated structure design with fixed power levels. The electromagnetic unit cannot be separated. When high-power motors designed for high-load scenarios are running under low-load conditions, the idle coils and iron cores will generate a lot of no-load iron losses, resulting in a significant reduction in energy efficiency ratio. This makes them unsuitable for energy-saving requirements in scenarios with fluctuating loads. If a small-power motor is selected to adapt to low loads, it cannot meet the power requirements of heavy-load conditions. Users usually need to equip multiple motors of different power or accept the problem of energy waste, resulting in high usage and operating costs.

[0003] (2) The utilization rate of the magnetic field is low, and the improvement of energy density is limited. The electromagnetic structure of existing conventional brushless motors can only drive the permanent magnet using the magnetic field on one side of the coil. The magnetic field on the side of the coil facing away from the permanent magnet is completely dissipated, and the magnetic field energy utilization rate is less than 50%. In order to achieve the target output power, it is necessary to increase the amount of coil and iron core, which directly leads to an increase in the weight of the motor and a decrease in power density. It is difficult to meet the high energy density application requirements of tethered drones, which have strict requirements for the weight of the power system.

[0004] (3) Poor adaptability of heat dissipation scheme and insufficient reliability under high load operation. High-power permanent magnet brushless motors generate significantly more heat when multiple coils operate simultaneously. Existing cooling solutions often employ external cooling fans or liquid cooling structures. External cooling fans require additional drive components and energy consumption, and the airflow cannot fully cover all heat-generating cores inside the motor, resulting in low cooling efficiency. Liquid cooling structures require supporting pump sets, pipelines, and other accessories, significantly increasing the weight and complexity of the entire machine, leading to high maintenance costs and the risk of leakage, making them unsuitable for harsh applications such as high-altitude and high-vibration environments. Some self-air-cooled motors have unreasonable flow channel designs, resulting in poor internal airflow circulation and severe internal heat accumulation during high-load operation. This can easily cause faults such as permanent magnet demagnetization and coil insulation aging, significantly shortening the motor's lifespan.

[0005] To address the aforementioned industry pain points, there is an urgent need to develop a new type of motor system that combines high energy density, multi-condition energy efficiency adaptability, and high-reliability heat dissipation to meet the application needs of related fields. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, the present invention aims to provide a high energy density combined air-cooled motor system and its control method. Through a detachable modular electromagnetic unit structure, a dual-sided magnetic field coupling design, a coaxial integrated forced air-cooling architecture, and adaptive control logic with matched modular configuration, the system achieves flexible adjustment of motor power according to operating conditions, improved energy efficiency under multiple operating conditions, optimized overall energy density, and stable heat dissipation under high load.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: A high-energy-density combined air-cooled motor system includes: The housing assembly, which encloses and forms a motor housing cavity, includes an upper cover, a lower cover, and a carbon fiber outer shell arranged coaxially. The lower cover has several air inlets evenly distributed around its circumference. The carbon fiber outer shell has air inlet slots evenly distributed around its bottom circumference and air outlet slots evenly distributed around its top circumference. The air inlets, air inlet slots, motor housing cavity, and air outlet slots are connected in sequence to form a through-type air-cooling channel. A rotating assembly is rotatably assembled inside the housing assembly, including a motor shaft rotatably connected to the center of the upper and lower covers. A fan blade is fixedly mounted on the motor shaft. The fan blade is located in the motor housing cavity and corresponds to the position of the air-cooling channel. It is used to drive the airflow to circulate in the air-cooling channel by rotating synchronously with the motor shaft. The electromagnetic drive assembly is used to drive the rotating assembly to operate. It includes a magnetic plate fixed stator, several permanent magnets and multiple sets of modular electromagnetic units. The magnetic plate fixed stator is coaxially mounted on the outside of the wind blades, and several permanent magnets are evenly distributed around the circumference of the magnetic plate fixed stator. The multiple sets of modular electromagnetic units are detachably snapped into the lower cover. Multiple modular electromagnetic units can be selectively installed and removed according to load conditions to match different power output requirements.

[0008] Preferably, each modular electromagnetic unit includes an arc-shaped iron core and a coil wound around the arc-shaped iron core. The two ends of the arc-shaped iron core extend to the two axial ends of the magnetic plate fixing stator, so as to make the double magnetic field generated by the coil act synchronously on the permanent magnet.

[0009] Preferably, the upper surface of the lower cover has several slots evenly distributed around its circumference, and the bottom end of the arc-shaped iron core is fixedly engaged with each slot. The modular electromagnetic unit can be quickly assembled and disassembled without tools through the slots.

[0010] Preferably, the end of the arc-shaped iron core away from the slot is provided with multiple coil fixing parts, the coils are wound in layers on the coil fixing parts, and multiple sets of coils are distributed in an array along the circumference of the magnetic sheet fixing stator.

[0011] Preferably, the air inlet is fan-shaped, and several fan-shaped air inlets are arranged in a circular array with the motor shaft as the center; both the air inlet groove and the air outlet groove are strip-shaped.

[0012] Preferably, the permanent magnet is embedded in the outer peripheral wall of the magnetic sheet fixing stator, and the inner side wall of the arc-shaped iron core is fitted with the permanent magnet with a gap to form a double-sided magnetic field coupling gap.

[0013] A control method for a high-energy-density combined air-cooled motor system, based on the aforementioned system, includes the following steps: Based on the equipment load power requirements, a grouped symmetrical configuration strategy is adopted to assemble the corresponding number of modular electromagnetic units; A preset driving current is applied to the coil, causing the coil to generate a double-sided magnetic field that acts synchronously on the permanent magnet on the magnetic sheet fixed stator, driving the magnetic sheet fixed stator to rotate synchronously with the motor shaft; When the motor shaft rotates, it drives the fan blades to rotate synchronously, driving the external airflow to enter the motor housing cavity through the air inlet and air inlet slot. After cooling the coil and permanent magnet, the airflow is discharged through the air outlet slot, completing the forced air cooling cycle. Based on the configuration of the modular electromagnetic unit and the real-time speed of the motor shaft, current adaptive matching control is performed; Among them, the preset load power threshold is used to equip all N groups, N / 2 groups and N / 3 groups of modular electromagnetic units when the required load power is ≥80% of the preset load power threshold, ≥30% of the preset load power threshold and <80% of the preset load power threshold and <30% of the preset load power threshold, respectively. N≥8 and the total number of modular electromagnetic units is even and symmetrically arranged.

[0014] Preferably, when performing current adaptive matching control, it includes: Identify the symmetrical grouping state of the currently assembled modular electromagnetic units, match the pre-stored double-sided magnetic field coupling phase parameters under the corresponding group to generate an initial driving current, and replace the preset driving current with the initial driving current. By dynamically adjusting the current amplitude based on the real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the double-sided coupling synchronization error of the output magnetic field of each modular electromagnetic unit is ≤1%.

[0015] Preferably, when dynamically adjusting the current amplitude based on the real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the following is included: Calculate the real-time heat dissipation efficiency threshold of the air-cooled channel based on the current motor shaft speed, and compare the real-time coil temperature with the upper limit of the allowable temperature corresponding to the real-time heat dissipation efficiency threshold. When the temperature exceeds the upper limit of the allowable temperature and the difference is ≤5℃, the current amplitude of each group of modular electromagnetic units is reduced synchronously according to the principle of equal adjustment of symmetrical grouping; when the temperature exceeds the upper limit of the allowable temperature and the difference is >5℃, the current amplitude of the symmetrical group of modular electromagnetic units arranged at intervals is reduced in turn, while ensuring that the output torque fluctuation amplitude is ≤3%.

[0016] Preferably, when calculating the real-time heat dissipation efficiency threshold of the air-cooled flow channel based on the current motor shaft speed, the following steps are included: Obtain the total number of modular electromagnetic units currently assembled, and match the pre-stored flow channel resistance correction coefficient for the corresponding number. Based on the current real-time speed of the motor shaft and the flow channel resistance correction coefficient, combined with the preset flow area parameters of the air inlet, air inlet slot and air outlet slot, the theoretical air flow rate of the air-cooled flow channel per unit time is obtained. Multiply the theoretical airflow rate by the heat transfer efficiency coefficient that is dynamically calibrated with ambient temperature to obtain the real-time heat dissipation efficiency threshold of the air-cooled channel under the current operating conditions.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention adopts a detachable modular electromagnetic unit design, which can quickly adjust the number of electromagnetic units assembled according to the load power requirements by grouping symmetry strategy: in high load conditions, all units are fully equipped to meet the heavy load power requirements, and in medium and low load conditions, only the corresponding proportion of symmetrical units are assembled, which can greatly reduce no-load iron loss, and the average energy efficiency of multiple conditions is significantly improved compared with traditional fixed power motors; it can cover multiple load fluctuation scenarios without equipping multiple motors of different power levels, reduce equipment procurement costs, and adapt to application scenarios with large load fluctuations such as tethered drones and heavy-duty servo equipment.

[0018] (2) This invention breaks through the design limitation of traditional motors that only utilize the magnetic field on one side of the coil. By using the arc-shaped iron core axial extension structure, the synchronous coupling drive of the magnetic field on both sides is achieved. The energy utilization rate of the coil magnetic field is nearly doubled compared with the traditional motor. Under the same output power requirement, the amount of coil and iron core can be reduced by 30%~40%. Combined with the lightweight design of the high-strength carbon fiber shell, the weight of the whole machine is significantly reduced compared with the traditional motor of the same power. The power density is high, which fully meets the stringent requirements of high-altitude work equipment for the weight of the power system.

[0019] (3) The heat dissipation channel is deeply integrated with the power structure, eliminating the need for additional external cooling fans, liquid cooling pumps and other accessories. This reduces the energy consumption and failure points of the heat dissipation system, and further reduces the weight of the whole machine. The through-type air cooling channel and coaxial follow-up fan blades work together to automatically adapt the heat dissipation capacity to the motor speed. Under high load conditions, the heat dissipation efficiency is significantly improved compared with traditional self-air-cooled motors. This can effectively avoid failures such as high temperature demagnetization of permanent magnets and aging of coil insulation, extend the service life of the motor, and eliminate the risk of liquid leakage from the liquid cooling system.

[0020] (4) The modular electromagnetic unit is fixed by fastener-free snap-fit ​​through standardized slots, and can be disassembled and assembled without tools. The replacement time of a single electromagnetic unit is short. The motor power level can be adjusted on-site according to the needs of the operation scenario without returning to the factory for modification. When a single electromagnetic unit fails, only the corresponding faulty unit needs to be replaced, without scrapping the entire motor. The maintenance cost is significantly reduced compared with the traditional integrated motor.

[0021] (5) The matching adaptive control method can automatically match the phase parameters of the magnetic field coupling on both sides according to the assembly status of the modular electromagnetic unit, ensuring that the magnetic field synchronization error of each group of units is ≤1%, avoiding magnetic field cancellation or torque fluctuation; the gradient over-temperature current regulation strategy can dynamically adjust the current amplitude according to the principle of symmetry when the temperature exceeds the limit, always ensuring that the output torque fluctuation amplitude is ≤3%, taking into account both heat dissipation safety and power output stability, and adapting to application scenarios with high power stability requirements such as industrial servo and UAV flight power.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0023] Figure 1 This is a first overall structural diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 2 This is a second overall structural diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 3 This is a first internal structure diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 4 This is a second internal structure diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 5 This is a third internal structure diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 6 This is a fourth internal structure diagram of the high energy density combined air-cooled motor system according to an embodiment of the present invention; Figure 7 This is a block diagram of the current adaptive matching control logic in an embodiment of the present invention; Figure 8 This is a logic block diagram of dynamic current amplitude adjustment based on temperature-heat dissipation efficiency coupling in an embodiment of the present invention; Figure 9 This is a block diagram of the real-time heat dissipation efficiency threshold calculation logic in an embodiment of the present invention.

[0024] Explanation of the reference numerals: 1. Top cover; 2. Bottom cover; 3. Carbon fiber shell; 4. Air inlet; 5. Air inlet slot; 6. Air outlet slot; 7. Motor shaft; 8. Fan blade; 9. Magnetic plate fixing stator; 10. Permanent magnet; 11. Arc-shaped iron core; 12. Coil; 13. Slot; 14. Coil fixing part. Detailed Implementation

[0025] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0026] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0027] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0029] Example 1, see Figure 1 and Figure 2 The present invention provides a high energy density combined air-cooled motor system, including a housing assembly, a rotating assembly and an electromagnetic drive assembly. The housing assembly surrounds to form a motor housing cavity, the rotating assembly is rotatably assembled inside the housing assembly, and the electromagnetic drive assembly is used to drive the rotating assembly to operate. The housing assembly includes an upper cover 1, a lower cover 2 and a carbon fiber outer shell 3 arranged coaxially. The lower cover 2 has several air inlets 4 evenly distributed around its circumference. The carbon fiber outer shell 3 has air inlet grooves 5 evenly distributed around its bottom circumference and air outlet grooves 6 evenly distributed around its top circumference. The air inlets 4, air inlet grooves 5, motor housing cavity and air outlet grooves 6 are connected in sequence to form a through-type air-cooling channel. The rotating assembly includes a motor shaft 7 rotatably connected to the center of the upper cover 1 and the lower cover 2. A fan blade 8 is fixedly mounted on the motor shaft 7. The fan blade 8 is located in the motor housing cavity and corresponds to the position of the air-cooling channel. It is used to drive the airflow to circulate in the air-cooling channel by rotating synchronously with the motor shaft 7. The electromagnetic drive assembly includes a magnetic sheet fixed stator 9, several permanent magnets 10, and multiple sets of modular electromagnetic units. The magnetic sheet fixed stator 9 is coaxially mounted on the outside of the fan blade 8, and several permanent magnets 10 are evenly distributed around the magnetic sheet fixed stator 9. The multiple sets of modular electromagnetic units are detachably snapped onto the lower cover 2. Multiple modular electromagnetic units can be selectively installed and removed according to load conditions to match different power output requirements.

[0030] Specifically, this motor system addresses the industry pain points of existing high-power motors, such as low energy efficiency under low load, insufficient magnetic field utilization, and weak heat dissipation. Through the synergistic effect of three core technologies—modular power adaptation, dual-sided magnetic field coupling, and synchronous forced air cooling—it achieves high energy density output, optimized energy efficiency under all operating conditions, and high reliability operation. The specific principle is as follows: (1) Modular power adaptive matching principle The electromagnetic drive unit of this system adopts a detachable modular design: multiple sets of arc-shaped iron cores 11 with coils 12 can be detachably snapped onto the end face of the lower cover 2 through slots 13. The corresponding number of electromagnetic units can be selectively installed / removed according to the actual load conditions and the group symmetrical configuration strategy, and the electromagnetic units are always arranged in an even number symmetrical manner to ensure the uniformity of the air gap magnetic field of the motor and control the torque fluctuation within 3%.

[0031] High load conditions (load ≥ 80% of rated power): Install all N sets (N ≥ 8) of modular electromagnetic units to meet heavy load requirements with full power output; Medium load condition (rated power 30% ≤ load < 80%): Install N / 2 sets of symmetrically arranged electromagnetic units to reduce iron loss caused by ineffective coil 12; Low load conditions (load < 30% of rated power): Install N / 3 sets of symmetrically arranged electromagnetic units to simultaneously reduce iron loss and overall weight, and significantly improve energy efficiency under light load conditions.

[0032] (2) High-efficiency coupling driving principle of dual-sided magnetic field This system breaks through the design limitations of traditional motors that only utilize a single-sided magnetic field. The two ends of the arc-shaped iron core 11 extend to the upper and lower ends of the axial direction of the magnetic sheet fixed stator 9, respectively. The double-sided magnetic field generated by the coil 12 after being energized can act synchronously on the permanent magnets 10 uniformly arranged on the outer periphery of the magnetic sheet fixed stator 9. The magnetic field coupling utilization rate is nearly doubled compared with traditional motors. Under the same power output requirements, the amount of coil 12 can be reduced, further reducing the overall weight and increasing the energy density.

[0033] During operation, the control system will automatically match the corresponding double-sided magnetic field coupling phase parameters according to the number of electromagnetic units currently assembled and the symmetrical grouping status, so as to control the double-sided coupling synchronization error of the output magnetic field of each group of electromagnetic units within 1% and ensure the smoothness of power output.

[0034] (3) Coaxial synchronous forced air cooling principle The heat dissipation channel and power structure of this system are integrated, eliminating the need for an additional cooling fan: the fan-shaped air inlets evenly distributed around the circumference of the lower cover 2, the air inlet slot 5 at the bottom of the carbon fiber shell 3, the motor housing cavity, and the air outlet slot 6 at the top of the carbon fiber shell 3 are connected in sequence to form a through-type axial flow channel; the fan blades 8 are coaxially fixed with the motor shaft 7 and rotate synchronously with the motor shaft 7, driving the external cold airflow to pass through the entire motor from bottom to top, directly exchanging heat with the coil 12 and permanent magnet 10 of the heat-generating core before being discharged from the top air outlet slot 6.

[0035] Automatic adaptation of heat dissipation efficiency to motor speed: When the motor speed is higher, the output power is greater, and the heat generation is higher, the speed of the fan blades 8 increases synchronously, and the airflow increases accordingly. The control system can dynamically adjust the current amplitude based on the real-time coil temperature and the flow channel resistance coefficient to ensure that the motor always operates within a safe temperature range.

[0036] In one possible embodiment, see [reference] Figure 5 Each modular electromagnetic unit includes an arc-shaped iron core 11 and a coil 12 wound around the arc-shaped iron core 11. The two ends of the arc-shaped iron core 11 extend to the two axial ends of the magnetic sheet fixed stator 9, respectively, so that the double magnetic field generated by the coil 12 acts synchronously on the permanent magnet 10.

[0037] Specifically, this structural design addresses the industry pain point that traditional brushless motors can only utilize the magnetic field on one side of coil 12, resulting in wasted magnetic field energy. It maximizes the utilization of magnetic field energy through an innovative iron core structure. The specific principle is as follows: In traditional brushless motors, the iron core is only arranged radially on one side of the permanent magnet 10. When the coil 12 is energized, only the magnetic field on the side facing the permanent magnet 10 participates in doing work, while the magnetic field on the side facing away from the permanent magnet 10 is completely dissipated and has no value. In this design, the iron core of the electromagnetic unit is set as an arc-shaped structure, with its axial length covering the entire axial span of the magnetic sheet fixed stator 9. Both ends extend to the outer side of the upper and lower end faces of the magnetic sheet fixed stator 9, forming a double-sided correspondence with the circumferentially arranged permanent magnets 10.

[0038] When an alternating driving current is applied to the coil 12, the arc-shaped iron core 11 is magnetized. Its upper and lower ends will synchronously form an alternating polarity induced magnetic field. The magnetic fields at the two ends act synchronously on the upper and lower sides of the permanent magnet 10 along the axis, forming a bidirectional magnetic pull drive on the permanent magnet 10. The magnetic field on the other side, which would be dissipated in the traditional design, also participates in the power output, and there is no waste of magnetic field energy.

[0039] This design can nearly double the magnetic field utilization of coil 12. Under the premise of outputting the same torque, it can reduce the amount of coil 12 and iron core by 30% to 40%, which reduces the overall weight of the motor and reduces the no-load loss of the iron core, further improving the energy density and operating efficiency of the motor. At the same time, the arc-shaped structure is compatible with the assembly requirements of the motor's circumferential array and is fully compatible with the modular disassembly and assembly design, without affecting the power matching flexibility under multiple operating conditions.

[0040] In one possible embodiment, see [reference] Figure 6 The upper surface of the lower cover 2 is evenly distributed with several slots 13. The bottom end of the arc-shaped iron core 11 is fixedly engaged with the slots 13 one by one. The modular electromagnetic unit can be quickly disassembled and assembled without tools through the slots 13.

[0041] Specifically, this structural design addresses the pain points of traditional fixed-power motors, such as the inability to flexibly adjust power and high maintenance costs. It achieves rapid assembly and disassembly of the electromagnetic unit through a pre-positioning slot structure, providing a hardware foundation for power adaptation under multiple operating conditions. The specific principle is as follows: Traditional motors typically fix their iron core and coil 12 inside the casing using adhesive bonding or bolting, making the structure non-disassembleable. Adjusting the output power requires replacing the entire motor, which cannot flexibly adapt to high and low load switching needs. This design, however, uses standardized slots uniformly machined around the upper surface of the lower cover 2 according to the preset electromagnetic array positions. These slots perfectly match the bottom shape of the arc-shaped iron core 11. The installation accuracy and clamping force of all slots 13 are pre-calibrated, and their positions follow a symmetrical distribution rule, ensuring the uniformity of the magnetic field after the electromagnetic unit is installed from a hardware perspective.

[0042] The bottom end of the arc-shaped iron core 11 and the slot 13 adopt an interference fit / snap-on fastener-free structure, eliminating the need for additional bolts, adhesives, or other fixing media. For disassembly and assembly, only the top cover 1 and the carbon fiber outer shell need to be removed; the arc-shaped iron core 11 can then be slid outwards along the slot 13 to complete removal. For installation, the bottom end of the arc-shaped iron core 11 is aligned with the corresponding slot 13 and slid inwards to complete positioning and fixation. No tools are required throughout the process, significantly reducing the time spent on disassembly and assembly of a single electromagnetic unit. The slot 13 also integrates a foolproof design, allowing installation only in a preset direction to prevent positional deviations during manual assembly that could lead to magnetic field imbalance.

[0043] This structural design allows for the addition or removal of electromagnetic units on-site based on load requirements, without requiring factory modifications, making it perfectly suited for devices like tethered drones that need to switch loads in different scenarios. When a single electromagnetic unit fails, only the corresponding faulty unit needs to be replaced, without scrapping the entire motor, thus greatly reducing the maintenance cost throughout its entire life cycle. High accuracy of repeated assembly: The pre-positioning design of slot 13 ensures that the installation position deviation of the electromagnetic unit is small after multiple disassembly and assembly, which will not affect the magnetic field coupling accuracy and running stability of the motor.

[0044] In one possible embodiment, see [reference] Figure 3 and Figure 4 The arc-shaped iron core 11 has multiple coil fixing parts 14 at one end away from the slot 13. The coils 12 are wound in layers on the coil fixing parts 14, and multiple sets of coils 12 are distributed in a circular array along the magnetic sheet fixing stator 9.

[0045] Specifically, the bottom end of the arc-shaped iron core 11 is fixed by a pre-positioned slot in the lower cover 2. Multiple coil fixing parts 14 are set at the top of the core away from the slot 13, providing a standardized winding positioning reference for the coil 12. This replaces the traditional design of iron core without a fixed winding position, ensuring that the number of winding layers, turns, and spatial position accuracy of each group of coils 12 are completely uniform. From the hardware level, this ensures that the electromagnetic parameters of all modular electromagnetic units are consistent, avoiding the problem of magnetic field imbalance caused by winding deviation.

[0046] The coil 12 is fixed to the coil fixing part 14 by layered winding, which has two advantages compared with the traditional close-packed winding method: First, it increases the heat dissipation gap between turns and layers of the coil 12, so that the airflow of the motor through-type air cooling channel can directly pass through the gap of the coil 12 to carry away heat, which greatly improves the heat dissipation efficiency of the coil 12 and adapts to the heat dissipation requirements under high power operation; Second, layered winding can reduce the parasitic capacitance of the coil 12, reduce eddy current loss under high frequency drive conditions, and improve electromagnetic conversion efficiency.

[0047] Multiple sets of coils 12 are evenly arrayed along the circumference of the stator 9 fixed by the magnetic sheet. Combined with the symmetrical assembly of the modular electromagnetic units, this ensures that the alternating magnetic field generated by the coils 12 after being energized is evenly distributed in the circumferential direction, avoiding torque fluctuations and force imbalance of the permanent magnet 10 caused by uneven local magnetic field strength. At the same time, it is adapted to the core design of the dual-sided magnetic field coupling of this motor, so that the upper and lower dual-sided magnetic fields generated by each set of coils 12 can act synchronously on the permanent magnet 10 at the corresponding position, maximizing the utilization rate of the magnetic field.

[0048] The standardized coil fixing part 14 design ensures that the coil winding process of all modular electromagnetic units is completely uniform, and any unit can be used interchangeably. The motor performance after disassembly and assembly will not be affected by the difference in winding. This provides process support for the rapid disassembly and assembly adjustment of electromagnetic units under different load conditions.

[0049] This structure simultaneously addresses three requirements: heat dissipation performance, electromagnetic conversion efficiency, and modular adaptability. It is one of the core supporting structures for this motor to achieve high energy density and efficient operation under all working conditions.

[0050] In one possible embodiment, see [reference] Figure 1 and Figure 2 The air inlet 4 is fan-shaped, and several fan-shaped air inlets are arranged in a circular array around the motor shaft 7; the air inlet groove 5 and the air outlet groove 6 are both strip-shaped.

[0051] Specifically, the annular array structure of the fan-shaped air inlet is perfectly matched with the rotating flow field of the fan blades 8 arranged coaxially with the motor: The circular array arrangement centered on the motor shaft 7 ensures that the air intake is completely uniform in the circumferential direction, without any local air intake blind spots. After the airflow enters, it can evenly cover the coil area of ​​all modular electromagnetic units, avoiding the problem of insufficient heat dissipation of local coils 12. Compared to traditional circular or square openings, the fan-shaped opening can increase the flow area within the limited end face installation area of ​​the lower cover 2, thereby increasing the air intake per unit time. At the same time, the arc edge of the fan shape is adapted to the swirling direction generated by the rotation of the fan blades 8, which can reduce air intake resistance, reduce wind noise caused by airflow impact, and improve heat dissipation efficiency at high speeds.

[0052] Structural characteristics and airflow path of the strip groove adapted to the carbon fiber shell: Process adaptability: The strip groove can be directly stamped on the one-piece carbon fiber shell without complicated hole-making. After hole-making, the structural strength loss of the shell is smaller, avoiding the reduction of the shell's impact resistance due to too many holes. Flow channel adaptability: The bottom strip-shaped air inlet slot can evenly guide the swirling air entering from the fan-shaped air inlet to the full axial height area of ​​the motor housing cavity, covering all heat-generating components such as the arc-shaped iron core 11, coil 12, and permanent magnet 10; the top strip-shaped air outlet slot matches the axial upward path of the airflow, allowing the hot airflow after heat exchange to be discharged quickly, reducing exhaust resistance and preventing the hot airflow from accumulating inside the motor. Flexible adaptability: The length of the strip groove can be flexibly adjusted according to the motor power level, and it can adapt to different heat dissipation requirements without modifying the overall mold of the shell. At the same time, the narrow gap of the strip groove can prevent large particles of foreign objects from entering the motor.

[0053] The intake and exhaust structure works in conjunction with the coaxial fan blades 8 to allow airflow to flow along a path with low resistance. The heat dissipation efficiency is automatically matched with the motor speed: the higher the motor output power and the faster the speed, the more the intake volume increases. This ensures the heat dissipation needs of multiple coils 12 under high load operation without increasing the energy consumption of the heat dissipation system.

[0054] In one possible embodiment, see [reference] Figure 3 The outer diameter of the fan blade 8 is matched with the inner diameter of the magnetic plate fixing stator 9.

[0055] In one possible embodiment, see [reference] Figure 4The permanent magnet 10 is embedded in the outer peripheral wall of the magnetic sheet fixing stator 9, and the inner side wall of the arc-shaped iron core 11 is in clearance fit with the permanent magnet 10 to form a double-sided magnetic field coupling gap.

[0056] Specifically, the permanent magnet 10 is embedded in the outer peripheral wall of the magnetic sheet fixing stator 9 so that the magnetic poles of the permanent magnet 10 are arranged outward, forming a radial correspondence with the modular arc-shaped iron core 11 surrounding the outside of the stator; the uniform gap reserved between the inner wall of the arc-shaped iron core 11 and the permanent magnet 10 is the magnetic field conduction air gap. The size of this gap is precisely calibrated, which can not only avoid physical friction interference between the permanent magnet 10 and the iron core during the rotation of the stator, but also control the loss in the magnetic field conduction process to the lowest level.

[0057] This design breaks through the limitation of traditional brushless motors that can only utilize the magnetic field on one side of the coil 12: In this design, the axial length of the arc-shaped iron core 11 completely covers the entire axial span of the magnetic sheet fixing stator 9, and the two ends extend to the outer side of the upper and lower end faces of the stator respectively; when the coil 12 is supplied with alternating drive current, the arc-shaped iron core 11 is magnetized. Not only will the area of ​​the inner wall of the iron core facing the permanent magnet 10 generate an induced magnetic field, but the upper and lower ends of the iron core will also generate induced magnetic fields with alternating polarities. The magnetic fields on both sides act on the upper and lower ends of the permanent magnet 10 through the reserved gap, forming a bidirectional magnetic pull drive. The idle magnetic field that would be dissipated in the traditional design also participates in the power output, and there is no waste of magnetic field energy.

[0058] This double-sided magnetic field coupling gap design allows the magnetic field utilization of coil 12 to be nearly doubled compared to traditional motors. Under the premise of outputting the same torque, it can reduce the amount of coil 12 and iron core by 30% to 40%, which reduces the overall weight of the motor and reduces the no-load loss of the iron core, further improving the energy density and operating efficiency of the motor. At the same time, this structure is fully compatible with the modular electromagnetic unit disassembly and assembly design, and will not affect the power matching flexibility under different load conditions.

[0059] In one possible embodiment, the upper cover 1, the lower cover 2 and the carbon fiber shell 3 are coaxially and sealed together by fasteners, and the two ends of the motor shaft 7 are rotatably engaged with the upper cover 1 and the lower cover 2 by bearings respectively.

[0060] Specifically, this structure is the basic assembly support structure for high energy density combined air-cooled motors, providing a fundamental guarantee for the modular design, efficient heat dissipation, and stable operation of the entire machine.

[0061] After the three components are coaxially aligned and fixed with fasteners, the coaxiality error between the internal rotating components (motor shaft 7, fan blades 8, magnetic plate fixed stator 9) and the fixed components (modular arc-shaped iron core 11, permanent magnet 10) is controlled within the design threshold. This avoids uneven coupling air gap between the permanent magnet 10 and the arc-shaped iron core 11 due to assembly deviations, and prevents problems such as decreased magnetic field coupling efficiency, increased torque fluctuation, and friction jamming of rotating components.

[0062] The design employs detachable fastener connections, rather than non-detachable processes such as bonding or welding. This allows for quick disassembly of the top cover 1 and carbon fiber outer shell 3 when the number of electromagnetic units needs to be adjusted to adapt to different load conditions, enabling the replacement of the arc-shaped iron core 11 without damaging the shell structure. Furthermore, the carbon fiber outer shell itself is high-strength and lightweight, and after coaxial assembly, the entire machine exhibits excellent rigidity, resisting deformation under high-speed operation and maintaining internal assembly precision over a long period.

[0063] The assembly design adopts a two-point support at both ends: The motor shaft 7 has high-precision bearings at both ends that are engaged with the center positioning holes of the upper and lower covers. Compared with the single-end support structure, it can withstand greater radial and axial loads and is suitable for the load requirements under high power output conditions. The bearing mounting reference is ensured by the coaxial assembly accuracy of the upper and lower covers, which can control the rotational runout of the motor shaft 7 to a very small range. This can reduce rotational vibration and noise, and also ensure the rotational accuracy of the fan blades 8 and the stator 9 fixed coaxially with the motor shaft 7. This avoids the fan blades 8 from being eccentric, which would lead to increased wind resistance and reduced heat dissipation efficiency. At the same time, it avoids fluctuations in the coupling gap between the permanent magnet 10 and the arc-shaped iron core 11 when the stator rotates, ensuring the stability of the magnetic field coupling on both sides and reducing torque fluctuations.

[0064] In one possible embodiment, when all modular electromagnetic units are energized, it is a high-load operating condition; when some modular electromagnetic units are removed and de-energized, it is a medium-low load operating condition. Under the medium-low load condition, the iron loss of the motor and the weight of the whole machine decrease simultaneously.

[0065] In one possible embodiment, the fan blade 8, the air inlet 4, the air inlet slot 5 and the air outlet slot 6 constitute a forced air cooling structure. When the motor shaft 7 rotates, the airflow passes through the motor housing cavity from bottom to top, and heats the coil 12 and the permanent magnet 10 simultaneously.

[0066] Specifically, this forced air cooling structure deeply integrates the heat dissipation channels with the motor's basic structure: The fan blades 8 and the motor shaft 7 are directly coaxially fixed, eliminating the need for an additional heat dissipation drive motor and transmission structure. This reduces the overall weight and energy consumption, and also avoids the failure points of an external heat dissipation system. The fan-shaped annular array of air inlets on the lower cover 2, the strip-shaped air inlet grooves at the bottom of the carbon fiber shell 3, and the strip-shaped air outlet grooves at the top are arranged to perfectly match the flow field characteristics generated by the rotation of the fan blades 8: the fan-shaped air inlets are adapted to the swirling direction of the fan blades, reducing air intake resistance and wind noise; the strip-shaped grooves are adapted to the carbon fiber shell stamping process, and the opening will not significantly reduce the structural strength of the shell, while the narrow slits can prevent large particles of foreign objects from entering the motor.

[0067] The entire heat dissipation process requires no additional control and is automatically triggered as the motor runs. When the motor shaft 7 drives the load to rotate, the fan blades 8 rotate synchronously, forming a negative pressure at the bottom of the motor housing cavity. This draws in external cold air from the fan-shaped air inlet of the lower cover 2 and the air inlet slot 5 at the bottom of the carbon fiber shell 3, spreading it evenly to the radial circumference of the housing cavity. As the cold air flows from bottom to top through the entire housing cavity, it directly contacts the core heating components (layered wound coils 12 and peripherally arranged permanent magnets 10) to complete heat exchange. The hot air carrying heat is finally discharged from the air outlet slot 6 at the top of the carbon fiber shell 3, covering all heating units.

[0068] The heat dissipation capacity can be automatically and dynamically matched according to the motor load: When the motor load is higher and the output power is greater, the motor speed increases synchronously, the airflow driven by the 8 fan blades increases linearly, and the heat dissipation capacity automatically adapts to the high heat demand under high load; while under low load conditions, after removing some modular electromagnetic units, the flow channel space is further increased, and the heat dissipation efficiency can still be maintained within a reasonable range without the need for additional adjustment of heat dissipation parameters.

[0069] Compared with traditional motor heat dissipation solutions, this design reduces weight and improves heat dissipation efficiency. It can effectively avoid the demagnetization of permanent magnet 10 and the aging of coil insulation 12 caused by high temperature, thus extending the service life of the motor. At the same time, it can adapt to the heat dissipation requirements of power adjustment under multiple operating conditions.

[0070] In one possible embodiment, the carbon fiber shell 3 is an integral carbon fiber shell, and both the air outlet groove 6 and the air inlet groove 5 are stamped through groove structures.

[0071] Specifically, the specific strength of carbon fiber composite material is more than three times that of aluminum alloy. Under the same structural rigidity requirements, the weight of the shell can be reduced by 35% to 45%, directly improving the power-to-weight ratio of the whole machine and meeting the design goal of high energy density. At the same time, the carbon fiber shell has excellent insulation properties, eliminating the need for an additional insulating liner between the shell and the coil 12, saving about 5% of internal space and reserving room for adding modular electromagnetic units. Moreover, the thermal expansion coefficient of carbon fiber is extremely low, and the deformation of the shell under high and low temperature conditions is less than 1 / 10 of that of the metal shell, which can ensure the coaxiality of the internal assembly for a long time, stabilize the magnetic field coupling gap between the permanent magnet 10 and the arc-shaped iron core 11, and avoid torque fluctuation and friction jamming problems caused by temperature changes.

[0072] The one-piece molding process eliminates the assembly gaps of multi-segment spliced ​​shells. On the one hand, it can greatly improve the vibration and impact resistance of the shell structure, and eliminate the risk of stress concentration fracture under high speed and heavy load conditions. On the other hand, it eliminates the need for additional glue to seal the splice, which simplifies the assembly process and completely avoids the loss of heat dissipation efficiency caused by air leakage in the splice gaps, ensuring the airtightness of the forced air cooling channel.

[0073] During the carbon fiber shell forming process, through grooves can be directly and synchronously stamped out, eliminating the need for subsequent secondary processing such as milling and drilling. This reduces the number of processes and significantly lowers mass production costs. Furthermore, the stamped groove edges are smooth and burr-free, preventing scratches on internal wiring and avoiding the problem of carbon fiber layer peeling caused by machining, resulting in better consistency in shell structural strength.

[0074] Example 2: The present invention also provides a control method for a high energy density combined air-cooled motor system, based on the above-mentioned high energy density combined air-cooled motor system, comprising the following steps: S1. Load matching: Based on the equipment load power requirements, a grouped symmetrical configuration strategy is adopted to assemble a corresponding number of modular electromagnetic units to ensure the uniformity of the air gap magnetic field of the motor and reduce torque fluctuation. S2, Magnetic field drive: A preset driving current is applied to the coil 12, so that the coil 12 generates a double magnetic field that acts synchronously on the permanent magnet 10 on the magnetic sheet fixed stator 9, driving the magnetic sheet fixed stator 9 to rotate synchronously with the motor shaft 7. S3. Synchronous heat dissipation: When the motor shaft 7 rotates, it drives the fan blades 8 to rotate synchronously, driving the external airflow to enter the motor housing cavity through the air inlet 4 and air inlet slot 5. After dissipating heat from the coil 12 and permanent magnet 10, the air is discharged through the air outlet slot 6, completing the forced air cooling cycle. S4. Current Matching: Based on the configuration status of the modular electromagnetic units (including the total number of units assembled and the symmetrical grouping status) and the real-time speed of the current motor shaft 7, current adaptive matching control is performed. The grouped symmetrical configuration strategy includes: a preset load power threshold; when the required load power is ≥80% of the preset load power threshold, all N groups of modular electromagnetic units are installed, N≥8; when the required load power is ≥30% of the preset load power threshold and <80% of the preset load power threshold, N / 2 groups of modular electromagnetic units are installed; when the required load power is <30% of the preset load power threshold, N / 3 groups of modular electromagnetic units are installed, and the total number of modular electromagnetic units is even and symmetrically arranged (even numbers are achieved by rounding up or down).

[0075] Specifically, this control method is a customized operating logic designed for the hardware of a modular, combined air-cooled motor. Its core design revolves around three major hardware characteristics of the motor: modular power configurability, dual-sided magnetic field coupling drive, and coaxial synchronous forced air cooling. It achieves high energy efficiency and high stability under all operating conditions from four dimensions: load adaptation, power output, heat dissipation coordination, and dynamic calibration. This method specifically addresses the technical problems of traditional fixed-power motors, such as low energy efficiency under light loads, insufficient magnetic field utilization, and mismatch between heat dissipation capacity and power. The specific principles of each step are as follows: S1. Load Matching (Modular Symmetric Configuration Principle): The hardware foundation for this step is that the motor electromagnetic unit adopts a modular design with a slot-type detachable mechanism, which can flexibly increase or decrease the number of electromagnetic units according to actual load requirements.

[0076] The underlying logic of the grouped symmetrical configuration strategy is to balance power adaptability and magnetic field uniformity: if the electromagnetic units are arranged asymmetrically, the air gap magnetic field strength in the circumferential direction of the motor will be significantly different, which can easily lead to problems such as large torque fluctuations, uneven force on the permanent magnet 10, and increased rotational vibration. Therefore, the rules clearly require that the total number of configurations is always even and arranged symmetrically. The configuration is ensured by rounding up / down, thus avoiding the risk of magnetic field imbalance from the hardware assembly level.

[0077] The configuration logic for the three power ranges corresponds to the energy efficiency optimization targets under different operating conditions: When the load is ≥80% of the rated power, all N sets (N≥8) of electromagnetic units are installed, and the full power output meets the heavy load requirements; When 30%≤load<80%rated power, install N / 2 sets of electromagnetic units to reduce the no-load iron loss caused by the ineffective coil 12; When the load is less than 30% of the rated power, N / 3 sets of electromagnetic units are installed to simultaneously reduce iron loss and overall weight, and significantly improve energy efficiency under light load conditions.

[0078] S2. Magnetic field drive (dual-sided magnetic field coupling drive principle): This step corresponds to the innovative magnetic field structure design of the motor: the axial length of the arc-shaped iron core 11 of the modular electromagnetic unit completely covers the upper and lower ends of the magnetic sheet fixing stator 9, breaking through the limitation of traditional motors that only utilize a single-sided magnetic field.

[0079] After the coil 12 is supplied with a preset driving current, the arc-shaped iron core 11 is magnetized. The upper and lower ends will synchronously form an alternating polarity induced magnetic field. The magnetic fields on both sides act synchronously on the upper and lower sides of the permanent magnet 10 along the axis, forming a bidirectional magnetic pull drive on the permanent magnet 10. The magnetic field on the other side, which would be dissipated in the traditional design, also participates in the power output. There is no waste of magnetic field energy. The magnetic field utilization rate is nearly doubled compared to the traditional motor. Under the same torque output, the amount of coil 12 and iron core can be reduced by 30% to 40%, further improving the energy density of the motor.

[0080] The preset drive current is based on the pre-calibrated basic phase parameters, which can ensure the polarity and phase matching of the magnetic fields on both sides and avoid problems such as magnetic field cancellation and excessive synchronization error.

[0081] S3, Synchronous heat dissipation (coaxial linkage air cooling principle): This step corresponds to the integrated design of the motor's heat dissipation channel and power structure, eliminating the need for an additional cooling fan, and the heat dissipation capacity can automatically adapt to the motor load: The fan blades 8 and the motor shaft 7 are rigidly connected and fixed. When the motor shaft 7 drives the load to rotate, the fan blades 8 rotate synchronously, forming a negative pressure in the motor housing cavity. This drives the external cold air to enter the motor through the fan-shaped air inlet of the lower cover 2 and the air inlet groove 5 at the bottom of the carbon fiber shell 3. The air flows from bottom to top through the entire housing cavity and directly contacts the core heat-generating components (coil 12, permanent magnet 10) for heat exchange. The hot air carrying heat is then discharged from the air outlet groove 6 at the top of the carbon fiber shell 3, completing the forced air cooling cycle.

[0082] When the motor speed is higher, the output power is greater, and the heat generation is higher, the speed of the fan blades increases synchronously, the airflow increases linearly, and the heat dissipation capacity automatically adapts to the high heat generation requirements under high load. No additional heat dissipation control logic is required, which reduces system complexity and avoids additional heat dissipation energy consumption.

[0083] S4 Current Matching (Adaptive Dynamic Calibration Principle): Since the number of electromagnetic units and the symmetrical grouping state change with load requirements, a fixed preset drive current cannot adapt to all configuration scenarios. Therefore, adaptive matching control is required. First, identify the total number of electromagnetic units currently assembled and their symmetrical grouping status. Match the pre-stored phase parameters of the dual-side magnetic field coupling under the corresponding group, and adjust the phase and waveform of the current to ensure that the dual-side coupling synchronization error of the output magnetic field of each electromagnetic unit is ≤1%, thus avoiding power loss and torque fluctuation problems caused by magnetic field asynchrony. Combined with the real-time rotational speed of the motor shaft 7, the real-time heat dissipation efficiency threshold of the air-cooled flow channel is calculated. The real-time coil temperature is compared with the upper limit of the allowable temperature. The current amplitude is dynamically adjusted according to the rule of "symmetric adjustment priority and controllable torque fluctuation": when the temperature exceeds the tolerance by ≤5℃, the current amplitude of all groups is reduced simultaneously. When the temperature exceeds the tolerance by >5℃, the current is reduced step by step according to the rule of symmetrical intervals. The output torque fluctuation amplitude is always guaranteed to be ≤3%, which avoids the demagnetization of permanent magnet 10 and the aging of insulation of coil 12 caused by high temperature, and ensures the stability of power output.

[0084] The four steps are interconnected: load matching completes the coarse adjustment of power level at the hardware level, magnetic field drive ensures efficient conversion of electromagnetic energy, synchronous heat dissipation provides reliable support for high-power operation, and current matching completes dynamic fine calibration under multiple operating conditions, ultimately achieving the motor to maintain high energy density, low operating loss and high stability in multiple load ranges.

[0085] In one possible embodiment, see [reference] Figure 7 When performing current adaptive matching control, it includes: Identify the symmetrical grouping state of the currently assembled modular electromagnetic units, match the pre-stored double-sided magnetic field coupling phase parameters under the corresponding group to generate an initial driving current, and replace the preset driving current with the initial driving current. By dynamically adjusting the current amplitude based on the real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the double-sided coupling synchronization error of the output magnetic field of each modular electromagnetic unit is ≤1%.

[0086] Specifically, this current adaptive matching control method designs a two-layer calibration mechanism to address the characteristics of modular motors, which are characterized by "flexible and variable configuration and high requirements for dual-sided magnetic field synchronization." It ensures magnetic field coupling efficiency and operational stability from two dimensions: static phase adaptation and dynamic amplitude adjustment. This solves the problems of preset current mismatch and temperature fluctuation interference with magnetic field synchronization after changes in modular configuration. The specific principle is as follows: (1) Static calibration principle of symmetric grouping identification + phase parameter matching The core issue in this section is resolving the mismatch between the default drive current and the hardware after changes in modular configuration. The factory-preset drive current is based on the parameters calibrated under the full configuration of all N electromagnetic units. However, when the user disassembles and reassembles the electromagnetic units according to the load requirements, the symmetrical grouping status will change (for example, 8 full configurations become 4 symmetrically arranged groups, or 3 required groups are rounded down to 4 symmetrically arranged groups, etc.). The magnetic field coupling phase characteristics corresponding to different grouping positions are significantly different. If the preset current under the full configuration status is continued to be used, it will cause the phase deviation of the upper and lower magnetic fields generated by coil 12 to be too large, resulting in magnetic field cancellation, increased synchronization error, increased torque fluctuation, and a decrease in magnetic field utilization of more than 15%.

[0087] The controller first uses the in-situ identification sensor built into slot 13 to automatically identify the number and specific distribution of the currently assembled modular electromagnetic units and confirm the symmetrical grouping status. Then, it calls the mapping table pre-stored in the controller to match the dual magnetic field coupling phase parameters (including current phase, waveform duty cycle, etc.) of the corresponding grouping mode that have been calibrated on the test bench in advance, and generates an initial drive current that is adapted to the current hardware configuration. This directly replaces the general preset current, and the synchronization error of the dual magnetic fields is controlled within a small range from the start of operation.

[0088] The pre-stored phase parameters were obtained by calibrating all possible symmetrical grouping modes on a machine during the R&D phase. The current parameters that minimize the synchronization error of the magnetic fields on both sides under each configuration were recorded. The direct lookup table method has a fast response speed, does not require complex real-time calculations, reduces the computing power requirements of the controller, and is suitable for application scenarios such as drones that have high requirements for response latency.

[0089] (2) Dynamic amplitude calibration principle of temperature + heat dissipation threshold linkage The core issue in this step is resolving the problem of temperature fluctuations interfering with magnetic field synchronization during operation. The resistance of coil 12 increases linearly with temperature, causing the magnetic field strength generated by coil 12 to decrease under the same current. Simultaneously, excessively high temperatures can lead to a decrease in the magnetic flux of permanent magnet 10. The combined effect of these two factors can cause a shift in the coupling characteristics of the two magnetic fields, easily leading to synchronization errors exceeding the allowable range, and even causing irreversible demagnetization of permanent magnet 10. Furthermore, the motor's heat dissipation capacity dynamically changes with speed (the higher the speed, the greater the airflow through the coaxial fan blades 8, and the stronger the heat dissipation capacity). Therefore, it is necessary to first calculate the real-time heat dissipation efficiency threshold of the air-cooled flow channel based on the current motor speed, which is the maximum amount of heat the cooling system can remove under the current operating conditions and the corresponding maximum allowable operating temperature of coil 12.

[0090] The controller collects the temperature of coil 12 in real time through the NTC temperature sensor built into coil 12 and compares it with the upper limit of the allowable temperature corresponding to the current heat dissipation efficiency threshold. It then dynamically adjusts the current amplitude in a closed loop: if the temperature is close to the upper limit of the allowable temperature, the current amplitude is appropriately reduced to prevent coil 12 from overheating. At the same time, it ensures that the strength of the magnetic fields on both sides is adjusted synchronously to avoid the problem of one side being too strong or too weak, and always keeps the synchronization error of the magnetic fields on both sides within 1%. If the temperature is much lower than the upper limit of the allowable temperature, the current amplitude can be appropriately increased to maximize the use of the current heat dissipation capacity and increase the output power.

[0091] This dynamic adjustment continuously calibrates the current by collecting temperature and speed data multiple times, and can adapt to various interference scenarios such as load fluctuations and changes in ambient temperature, taking into account both operating efficiency and reliability.

[0092] By employing a two-layer control logic of "static phase lookup table matching + dynamic amplitude closed-loop adjustment," the system not only adapts to the core characteristic of flexible configuration of modular motors but also addresses various dynamic disturbances during operation, ensuring the coupling efficiency of the dual magnetic fields. Compared to schemes without adaptive calibration, this effectively improves operational efficiency while avoiding overheating faults and extending the motor's service life.

[0093] In one possible embodiment, see [reference] Figure 8 When dynamically adjusting the current amplitude based on the real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the following applies: The real-time heat dissipation efficiency threshold of the air-cooled flow channel is calculated based on the current motor shaft speed 7, and the real-time coil temperature is compared with the upper limit of the allowable temperature corresponding to the real-time heat dissipation efficiency threshold. When the temperature exceeds the upper limit of the allowable temperature and the difference is ≤5℃, the current amplitude of each group of modular electromagnetic units is reduced synchronously according to the principle of equal adjustment of symmetrical grouping; when the temperature exceeds the upper limit of the allowable temperature and the difference is >5℃, the current amplitude of the symmetrical group of modular electromagnetic units arranged at intervals is reduced in turn, while ensuring that the output torque fluctuation amplitude is ≤3%.

[0094] Specifically, this method designs a gradient current regulation strategy for the structural characteristics of modularly symmetrically configured motors. The core objective is to minimize torque fluctuations in power output while rapidly suppressing motor overheating. This solves the problem that traditional uniform current reduction schemes easily lead to magnetic field imbalance and excessive torque fluctuations. It is suitable for applications with extremely high requirements for power stability, such as tethered drones and industrial servo equipment. The specific principle is as follows: (1) Calculation principle of real-time heat dissipation efficiency threshold based on rotational speed The core of this step is to achieve dynamic adaptation between the temperature threshold and the actual heat dissipation capacity, so as to avoid the fixed temperature threshold from excessively limiting the motor power output or causing the overheat protection to fail. This motor adopts a coaxial synchronous forced air-cooling structure, and its heat dissipation capacity is directly and strongly correlated with the speed of the motor shaft 7: the higher the speed, the greater the airflow driven by the coaxial fan blades 8, and the stronger the heat dissipation capacity; conversely, the heat dissipation capacity will decrease significantly at low speeds. At the same time, the number of modular electromagnetic units currently assembled will also affect the heat dissipation efficiency: the more units assembled, the greater the wind resistance of the internal flow channel of the motor, the lower the airflow at the same speed, and the corresponding decrease in heat dissipation capacity.

[0095] Therefore, the threshold calculation first matches the pre-stored flow channel resistance correction coefficient corresponding to the total number of electromagnetic units. Then, it combines the real-time motor speed, the pre-stored flow area parameters of the inlet and outlet, and the heat transfer coefficient calibrated by the ambient temperature to calculate the maximum amount of heat that the air-cooled flow channel can remove per unit time under the current operating conditions, thus deriving the upper limit of the coil's allowable temperature under that condition. This threshold dynamically changes with the operating conditions: the upper limit of the allowable temperature is higher under high speed and high heat dissipation capacity, maximizing the release of motor power; the upper limit of the allowable temperature is lower under low speed and low heat dissipation capacity, avoiding the risk of overheating. Compared with a fixed temperature threshold solution, this can improve the average output power of the motor.

[0096] (2) Torque stability guarantee principle of gradient flow regulation strategy Differentiated current regulation rules are adopted for different degrees of overheating. The core is to always maintain the magnetic field symmetry in the circumferential direction of the motor and control the torque fluctuation within the industry-acceptable threshold of 3% (under this fluctuation, drones and industrial equipment will not experience attitude jitter or precision deviation issues). Mild over-temperature scenario (excess ≤ 5℃): Symmetrical equal-volume flow adjustment; In this scenario, only a small reduction in current is needed to bring the temperature back to a safe range. Therefore, a strategy is adopted to synchronously reduce the same current amplitude of all operating modular electromagnetic units: the magnetic field strength at all locations is reduced synchronously and proportionally, the air gap magnetic field in the circumferential direction of the motor remains uniform and symmetrical, and almost no additional torque fluctuations are generated. The power output is not noticeable during the current adjustment process, which takes into account both heat dissipation requirements and operational stability.

[0097] Moderate to severe over-temperature (over-range >5℃) scenario: Flow adjustment is performed sequentially in symmetrically spaced groups; In this scenario, a significant current reduction is needed to quickly suppress the temperature rise. If the current reduction of all groups is still adopted simultaneously, the current reduction may be too large, resulting in excessive power loss, or the cooling target may not be achieved quickly. Therefore, a strategy of sequential current reduction for symmetrically arranged groups is adopted: the rule of "prioritizing the current reduction of groups arranged at intervals of 180 degrees" is followed. For example, in an 8-group symmetrically arranged electromagnetic unit, the current of the symmetrically arranged groups such as the 1st and 5th groups (180 degrees symmetrical) and the 3rd and 7th groups (180 degrees symmetrical) is reduced synchronously first. If the temperature still does not drop, the current of the remaining groups 2nd, 6th, 4th, and 8th groups is reduced.

[0098] The advantage of this strategy is that the magnetic field is always symmetrically distributed in the circumferential direction during the current reduction process, and there will be no imbalance problem of the magnetic field being too strong or too weak on one side. While achieving large current reduction and rapid cooling, the torque fluctuation range can be kept within 3%, avoiding sudden changes in power output that could lead to equipment failure.

[0099] This gradient current regulation strategy achieves rapid response to overheating risks while minimizing the impact of the current regulation process on power stability. Compared with the traditional unified current reduction scheme, torque fluctuation is significantly reduced, cooling response speed is significantly improved, and it adapts to the flexible configuration characteristics of modular motors under multiple operating conditions, meeting the needs of high-reliability power scenarios.

[0100] In one possible embodiment, see [reference] Figure 9 When calculating the real-time heat dissipation efficiency threshold of the air-cooled flow channel based on the current motor shaft speed 7, it includes: First, obtain the total number of modular electromagnetic units currently assembled and match the pre-stored flow channel resistance correction coefficient for the corresponding number. Then, based on the real-time speed of the motor shaft 7 and the flow channel resistance correction coefficient, combined with the preset flow area parameters of the air inlet 4, air inlet slot 5, and air outlet slot 6, obtain the theoretical airflow rate of the air-cooled flow channel per unit time. Finally, multiply the theoretical airflow rate by the heat exchange efficiency coefficient dynamically calibrated with the ambient temperature to obtain the real-time heat dissipation efficiency threshold of the air-cooled flow channel under the current operating conditions.

[0101] Specifically, this step involves multi-parameter dynamic calibration to accurately calculate the maximum heat dissipation power that the cooling system can actually handle under the current operating conditions (i.e., the real-time heat dissipation efficiency threshold). This provides a reliable basis for subsequent temperature judgment and current adjustment, solving the problems of poor adaptability, easy power waste, or overheat protection failure in traditional fixed threshold schemes. The specific principle is explained in three steps: (1) Principle of matching the number of modular units with the wind resistance correction coefficient The core of this step is to quantify the blocking effect of modular configuration on the flow channel: the modular electromagnetic unit is assembled in the air-cooled flow channel inside the motor, which will occupy part of the flow channel space and increase the resistance of airflow. The more modular electromagnetic units are assembled, the smaller the effective flow area of ​​the flow channel and the greater the wind resistance. At the same speed, the actual airflow that can enter the motor is lower.

[0102] During the R&D phase, the corresponding wind resistance parameters are tested one by one on the test bench for all possible assembly quantities (such as 8 groups, 4 groups, 2 groups, etc.), and a mapping table is pre-stored in the controller. During operation, the total number of units currently assembled can be identified by the in-situ sensor in slot 13, and the corresponding wind resistance correction coefficient can be directly obtained by looking up the table. There is no need to perform complex flow field calculations in real time, which greatly reduces the computing power requirement of the controller and the response delay can be controlled within 10ms, adapting to the high real-time control requirements.

[0103] (2) Principle of theoretical gas flow rate calculation This step is based on the aerodynamic characteristics of the axial fan and the flow characteristics of the flow channel to calculate the actual amount of cold air that can enter the motor under the current operating conditions: This motor adopts an axial fan blade that is rigidly connected to the motor shaft 7. The air flow rate pumped by the fan blade is approximately linearly positively correlated with the speed of the motor shaft 7 (the higher the speed, the greater the amount of air driven per unit time); the flow area of ​​the air inlet 4, the air inlet slot 5, and the air outlet slot 6 are fixed parameters that have been calibrated at the factory, which determine the maximum flow limit of the flow channel.

[0104] By combining the wind resistance correction coefficient obtained in the first step with the original theoretical flow rate corresponding to the speed, we can obtain the actual mass of cold air that can enter the motor per unit time under the current operating conditions. This is the core basic parameter of heat dissipation capacity: the larger the air flow rate, the higher the total heat exchange capacity.

[0105] (3) Principle of dynamic calibration of heat exchange efficiency This step is based on Newton's law of cooling to complete the final calibration of heat dissipation capacity: Under the same airflow, the actual amount of heat that can be carried away is directly related to the temperature difference between coil 12 and the environment. The higher the ambient temperature, the smaller the temperature difference between the hot and cold sides, the less heat can be carried away by the same volume of air, and the lower the heat exchange efficiency.

[0106] Therefore, the controller will collect ambient temperature data outside the motor in real time, call the pre-stored heat exchange efficiency calibration curve (obtained from bench heat exchange tests under different ambient temperatures), and dynamically correct the theoretical heat dissipation corresponding to the theoretical air flow rate. The final value obtained is the maximum amount of heat that the heat dissipation system can remove under the current operating conditions, which is the real-time heat dissipation efficiency threshold, corresponding to the highest allowable coil operating temperature under this operating condition.

[0107] This three-level computing logic takes into account the differences in modular configuration, the dynamic nature of operating conditions, and the fluctuation of ambient temperature. The calculation accuracy of the heat dissipation efficiency threshold is significantly improved compared with the traditional fixed threshold scheme. It avoids the waste of motor power caused by setting the threshold too low in low temperature / low load scenarios, and also avoids the overheating failure caused by setting the threshold too high in high temperature / high load scenarios. At the same time, the entire process adopts a lookup table + linear calculation method, with extremely low computing power requirements, which can be adapted to the real-time operation requirements of embedded controllers.

[0108] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A high energy density packaged air-cooled electric machine system, characterized by, include: The housing assembly, which encloses and forms a motor housing cavity, includes an upper cover, a lower cover, and a carbon fiber outer shell arranged coaxially. The lower cover has several air inlets evenly distributed around its circumference. The carbon fiber outer shell has air inlet slots evenly distributed around its bottom circumference and air outlet slots evenly distributed around its top circumference. The air inlets, air inlet slots, motor housing cavity, and air outlet slots are connected in sequence to form a through-type air-cooling channel. A rotating assembly is rotatably assembled inside the housing assembly, including a motor shaft rotatably connected to the center of the upper and lower covers. A fan blade is fixedly mounted on the motor shaft. The fan blade is located in the motor housing cavity and corresponds to the position of the air-cooling channel. It is used to drive the airflow to circulate in the air-cooling channel by rotating synchronously with the motor shaft. The electromagnetic drive assembly is used to drive the rotating assembly to operate. It includes a magnetic plate fixed stator, several permanent magnets and multiple sets of modular electromagnetic units. The magnetic plate fixed stator is coaxially mounted on the outside of the wind blades, and several permanent magnets are evenly distributed around the circumference of the magnetic plate fixed stator. The multiple sets of modular electromagnetic units are detachably snapped into the lower cover. Multiple modular electromagnetic units can be selectively installed and removed according to load conditions to match different power output requirements.

2. The system of claim 1, wherein, Each modular electromagnetic unit includes an arc-shaped iron core and a coil wound around the arc-shaped iron core. The two ends of the arc-shaped iron core extend to the two axial ends of the magnetic plate fixing stator, so that the double magnetic field generated by the coil acts on the permanent magnet synchronously.

3. The system of claim 2, wherein, The upper surface of the lower cover has several slots evenly distributed around its circumference. The bottom end of the arc-shaped iron core is fixed in place by corresponding slots. The modular electromagnetic unit can be quickly assembled and disassembled without tools through the slots.

4. The system of claim 3, wherein, The arc-shaped iron core has multiple coil fixing parts at one end away from the slot. The coils are wound in layers on the coil fixing parts, and multiple sets of coils are distributed in an array along the circumference of the magnetic sheet fixing stator.

5. The system of claim 1, wherein, The air inlet is fan-shaped, and several fan-shaped air inlets are arranged in a circular array around the motor shaft; both the air inlet slot and the air outlet slot are strip-shaped.

6. The system of claim 2, wherein, The permanent magnet is embedded in the outer peripheral wall of the magnetic sheet fixing stator, and the inner side wall of the arc-shaped iron core is fitted with the permanent magnet with a gap to form a double magnetic field coupling gap.

7. A control method for a high energy density combined air-cooled motor system, based on the system described in any one of claims 1-6, characterized in that, Includes the following steps: Based on the equipment load power requirements, a grouped symmetrical configuration strategy is adopted to assemble the corresponding number of modular electromagnetic units; A preset driving current is applied to the coil, causing the coil to generate a double-sided magnetic field that acts synchronously on the permanent magnet on the magnetic sheet fixed stator, driving the magnetic sheet fixed stator to rotate synchronously with the motor shaft; When the motor shaft rotates, it drives the fan blades to rotate synchronously, driving the external airflow to enter the motor housing cavity through the air inlet and air inlet slot. After cooling the coil and permanent magnet, the airflow is discharged through the air outlet slot, completing the forced air cooling cycle. Based on the configuration of the modular electromagnetic unit and the real-time speed of the motor shaft, current adaptive matching control is performed; Among them, the preset load power threshold is used to equip all N groups, N / 2 groups and N / 3 groups of modular electromagnetic units when the required load power is ≥80% of the preset load power threshold, ≥30% of the preset load power threshold and <80% of the preset load power threshold and <30% of the preset load power threshold, respectively. N≥8 and the total number of modular electromagnetic units is even and symmetrically arranged.

8. The control method according to claim 7, characterized by, When performing current adaptive matching control, the following are included: Identify the symmetrical grouping state of the currently assembled modular electromagnetic units, match the pre-stored double-sided magnetic field coupling phase parameters under the corresponding group to generate an initial driving current, and replace the preset driving current with the initial driving current. By dynamically adjusting the current amplitude based on the real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the double-sided coupling synchronization error of the output magnetic field of each modular electromagnetic unit is ≤1%.

9. The control method according to claim 8, characterized by, When dynamically adjusting the current amplitude based on real-time coil temperature and the heat dissipation efficiency threshold of the air-cooled flow channel, the following applies: Calculate the real-time heat dissipation efficiency threshold of the air-cooled channel based on the current motor shaft speed, and compare the real-time coil temperature with the upper limit of the allowable temperature corresponding to the real-time heat dissipation efficiency threshold. When the temperature exceeds the upper limit of the allowable temperature and the difference is ≤5℃, the current amplitude of each group of modular electromagnetic units is reduced synchronously according to the principle of equal adjustment of symmetrical grouping; when the temperature exceeds the upper limit of the allowable temperature and the difference is >5℃, the current amplitude of the symmetrical group of modular electromagnetic units arranged at intervals is reduced in turn, while ensuring that the output torque fluctuation amplitude is ≤3%.

10. The control method according to claim 9, characterized by, When calculating the real-time heat dissipation efficiency threshold of the air-cooled flow channel based on the current motor shaft speed, the following is included: Obtain the total number of modular electromagnetic units currently assembled, and match the pre-stored flow channel resistance correction coefficient for the corresponding number. Based on the current real-time speed of the motor shaft and the flow channel resistance correction coefficient, combined with the preset flow area parameters of the air inlet, air inlet slot and air outlet slot, the theoretical air flow rate of the air-cooled flow channel per unit time is obtained. Multiply the theoretical airflow rate by the heat transfer efficiency coefficient that is dynamically calibrated with ambient temperature to obtain the real-time heat dissipation efficiency threshold of the air-cooled channel under the current operating conditions.

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