Control method and device of low-heating unmanned aerial vehicle motor controller and unmanned aerial vehicle

Abstract

The invention relates to the field of unmanned aerial vehicle motor control. The invention relates to an unmanned aerial vehicle, in particular to a control method and device of a low-heating unmanned aerial vehicle motor controller and an unmanned aerial vehicle. The invention provides a control method and device of a low-heating unmanned aerial vehicle motor controller and an unmanned aerial vehicle. Heating of the motor controller is reduced by switching the wave sending mode and the switching frequency of an inverter, and effective protection is carried out during over-temperature.

Description

Technical Field

[0001] The present invention relates to the field of drone motor control, and more specifically, to a control method, device and drone of a low-heat drone motor controller. Background Art

[0002] In today's technological wave, drones have become an outstanding representative of innovative technology with their wide range of applications. From aerial photography, environmental monitoring to agricultural plant protection and logistics distribution, drones are everywhere, greatly improving work efficiency, reducing labor costs, and even creating a new working model in some areas.

[0003] The flight of drones relies on the lift provided by the rotation of the power motor, and the power of the power motor comes from the three-phase PWM wave (PWM, Pulse-Width Modulation) sent by the motor controller. In terms of design, on the one hand, the power motor is required to provide high torque and high power to ensure sufficient flight power, and the corresponding motor controller needs to output PWM waves with sufficient power to the motor. On the other hand, the weight and volume of various components including the power motor and motor controller are strictly limited to ensure the weight and overall shape of the drone as light as possible. This feature is particularly evident in some drones with special purposes or high technical indicators, such as military-grade drones. The power motor provides high torque and high power output under limited volume and weight. The advantage is that the drone has strong performance and can fly faster and farther. The disadvantage is the high heat generated by the high torque and high power output and the limitation of heat dissipation on limited volume and weight. Both the power motor and the motor controller will generate a lot of heat. If the heat is too large and cannot be dissipated in time, it is undoubtedly dangerous for the drone. Summary of the invention

[0004] The purpose of the present invention is to provide a control method, device and drone of a low-heat UAV motor controller, which reduces the heating of the motor controller by switching the wave generation mode and switching frequency of the inverter and provides effective protection when overheating.

[0005] In order to achieve these purposes and other advantages according to the present invention, a control method of a low-heat UAV motor controller is provided, comprising the following steps:

[0006] Get the real-time temperature of the motor controller;

[0007] Determine the temperature range of the motor controller's real-time temperature and switch the inverter's wave generation mode and switching frequency:

[0008] When the real-time temperature of the motor controller is within the preset normal temperature range, the wave generation mode of the inverter is switched to SVPWM, and the switching frequency is switched to the first switching frequency;

[0009] When the real-time temperature of the motor controller is in the preset medium-high temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to the second switching frequency;

[0010] When the real-time temperature of the motor controller is within the preset high temperature range, the wave generation mode of the inverter is switched to DPWM, and the switching frequency is switched to the third switching frequency;

[0011] When the real-time temperature of the motor controller is within the preset over-temperature protection interval, the wave generation mode of the inverter is switched to 2PCDPWM, and the switching frequency is switched to the fourth switching frequency.

[0012] Furthermore, in the control method of a low-heat UAV motor controller, the normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C.

[0013] Furthermore, in the control method of a low-heat UAV motor controller, the second switching frequency is not less than the first switching frequency, the third switching frequency is not less than the second switching frequency, and the fourth switching frequency is not less than the third switching frequency.

[0014] Furthermore, in the control method of the low-heat UAV motor controller, the first switching frequency is 8 kHz, the second switching frequency is 6 kHz, the third switching frequency is 6 kHz, and the fourth switching frequency is 6 kHz.

[0015] The present invention also provides a control device for a low-heat UAV motor controller, comprising:

[0016] A monitoring module, which is used to obtain the real-time temperature of the motor controller;

[0017] The switching module receives the real-time temperature data of the motor controller sent by the acquisition module, determines the temperature range of the real-time temperature of the motor controller, and switches the wave generation mode and switching frequency of the inverter:

[0018] When the real-time temperature of the motor controller is within the preset normal temperature range, the wave generation mode of the inverter is switched to SVPWM, and the switching frequency is switched to the first switching frequency;

[0019] When the real-time temperature of the motor controller is in the preset medium-high temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to the second switching frequency;

[0020] When the real-time temperature of the motor controller is within the preset high temperature range, the wave generation mode of the inverter is switched to DPWM, and the switching frequency is switched to the third switching frequency;

[0021] When the real-time temperature of the motor controller is within the preset over-temperature protection interval, the wave generation mode of the inverter is switched to 2PCDPWM, and the switching frequency is switched to the fourth switching frequency.

[0022] Furthermore, in the control device of the low-heat UAV motor controller, the normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C.

[0023] Furthermore, in the control device of the low-heat UAV motor controller, the second switching frequency is not less than the first switching frequency, the third switching frequency is not less than the second switching frequency, and the fourth switching frequency is not less than the third switching frequency.

[0024] Furthermore, in the control device of the low-heat UAV motor controller, the first switching frequency is 8 kHz, the second switching frequency is 6 kHz, the third switching frequency is 6 kHz, and the fourth switching frequency is 6 kHz.

[0025] The present invention also provides a drone, comprising the above control device.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention switches the wave generation mode and switching frequency of the inverter based on the real-time temperature of the motor controller to reduce the heat generation of the motor controller and perform effective protection when overtemperature occurs, effectively reducing heat generation. Reducing the switching frequency can reduce the heat generation by about 1 / 4, switching from SVPWM to DPWM can reduce the heat generation by 1 / 3, and switching from DPWM to 2PCDPWM can reduce the heat generation by 1 / 2.

[0028] 2. The present invention has a low implementation cost and only requires modification of the software by adding a corresponding monitoring module, a switching module and an SVPWM modulation algorithm.

[0029] 3. The present invention meets the requirements of drones for high sensitivity to weight and volume, and reduces a large amount of heat generation only at the software level, without the need to add additional heat dissipation equipment or modify the structure;

[0030] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of a three-phase inverter described in an embodiment of the present invention;

[0032] Figure 2 A diagram showing the relationship between the switch state, phase voltage and space vector described in an embodiment of the present invention;

[0033] Figure 3 is a basic voltage space vector comparison diagram described in an embodiment of the present invention;

[0034] Figure 4 A synthesis and decomposition diagram of a reference voltage vector described in an embodiment of the present invention;

[0035] Figure 5 It is the SVPWM first quadrant three-phase waveform diagram described in the embodiment of the present invention;

[0036] Figure 6 It is a three-phase waveform diagram of the first quadrant of DVPWM described in an embodiment of the present invention;

[0037] Figure 7 2PCDPWM schematic diagram of the embodiment of the present invention;

[0038] Figure 8 It is a three-phase waveform diagram of the 2PCDPWM in the first quadrant D1 region described in an embodiment of the present invention;

[0039] Fig. 9 This is a three-phase waveform diagram of the 2PCDPWM in the first quadrant D2 region described in an embodiment of the present invention;

[0040] Fig.10 It is a three-phase waveform of the 2PCDPWM in the first quadrant D3 region described in the embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0042] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] Example 1

[0044] An embodiment of the present invention provides a control method for a low-heat UAV motor controller, comprising the following steps:

[0045] Get the real-time temperature of the motor controller;

[0046] Determine the temperature range of the motor controller's real-time temperature and switch the inverter's wave generation mode and switching frequency:

[0047] The normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C;

[0048] When the real-time temperature of the motor controller is within the preset normal temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to 8kHz;

[0049] When the real-time temperature of the motor controller is in the preset medium-high temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to 6kHz;

[0050] When the real-time temperature of the motor controller is in the preset high temperature range, the inverter's wave generation mode is switched to DPWM, and the switching frequency is switched to 6kHz;

[0051] When the real-time temperature of the motor controller is within the preset over-temperature protection range, the inverter's wave generation mode is switched to 2PCDPWM and the switching frequency is switched to 6kHz.

[0052] In the above embodiment, in the flight control system of the entire UAV, the motor controller receives commands from the flight attitude controller and actually controls the power motor to emit a three-phase PWM wave. It can be divided into two parts: a control module and a drive module. The control module is responsible for receiving commands and calculating a suitable modulation method, and the drive module is mainly responsible for switching the switch of the three-phase inverter to emit a modulated PWM wave to the motor and drive the motor to run. The rapid opening and closing of the switch in the three-phase inverter will generate a lot of heat, which is also the main source of heat generation for the entire motor controller. The switch switching mode of the three-phase inverter is subject to the control of the control module. Under the same other conditions, selecting different inverter control methods will have different heat generation, so the heat generation can be reduced by selecting different inverter control methods according to different situations.

[0053] The switching frequency of the inverter refers to the number of times the switching components inside the inverter are switched on and off per unit time. The heat is directly derived from the loss of each switching operation, so the heat generation is directly related to the switching frequency. For example, in this embodiment, switching the switching frequency from 8kHz to 6kHz can reduce the heat generation by about 1 / 4.

[0054] SVPWM is a modulation strategy based on vector voltage switching and control of converter operation. The SVPWM algorithm has the advantages of high harmonic optimization, high voltage utilization and fast dynamic response. In addition, this method is easy to digitize and has good compatibility with hardware platforms.

[0055] Figure 1 The schematic diagram of a three-phase inverter is shown in Figure 1. The inverter has three bridge arms a, b, and c. Each bridge arm has two switches. For example, the switch on phase a is V T1 and V T4 , which respectively control the conduction and disconnection of the upper and lower bridge arms of the phase. In a three-phase inverter, the two switch states on each phase bridge arm are complementary. If the upper switch of the phase is on, then the lower switch must be off. Let the switching function S x (x=a,b,c), when S a =1 means the upper switch of phase a is on and the lower switch is off. a = 0, the state is opposite. In this way, the three-phase inverter can obtain 8 switching states, namely: 000, 001, 010, 011, 100, 101, 110, 111.

[0056] The eight switching states can be synthesized into eight basic space vectors, namely V 0 ,V 1 ,V 2 ,V 3 ,V 4 ,V 5 ,V 6 ,V 7 , the relationship between switch state, phase voltage and space vector is as follows Figure 2 As shown. Among them, V 0 ,V 7 is the zero vector. 1 ,V 2 ,V 3 ,V 4 ,V 5 ,V 6 are non-zero vectors, they have the same modulus and their directions differ by 60°. The vertices of these six non-zero vectors are connected to form a regular hexagon, and the entire space is divided into six sectors. The basic voltage space vector comparison diagram is shown in Figure 3 shown.

[0057] Figure 3 Medium V out is the reference voltage vector, that is, the voltage vector of the desired output. out It can be at any position and can also change the amplitude. SVPWM uses 8 basic space vectors to synthesize any V by controlling the switch state. out .by Figure 4For example, using V 0 ,V 4 ,V 6 To synthesize V in sector I out . Let T s For a switching cycle, T 0 、T 4 、T 6 V 0 ,V 4 ,V 6 According to the volt-second balance principle, the action time can be obtained:

[0058]

[0059] exist Figure 4 middle,

[0060]

[0061] The basic principle of SVPWM is how to obtain eight basic voltage space vectors through a three-phase inverter, and then use the basic voltage space vectors to synthesize the desired output vector V out In the specific algorithm implementation, it is necessary to first determine the sector where the desired vector is located, and then use the two basic vectors adjacent to the sector and the zero vector to synthesize. There are two zero vectors, namely V 0 (000),V 7 (111). The difference between SVPWM and DPWM is the different choices of zero vector.

[0062] SVPWM uses two zero vectors in one synthesis, that is, two adjacent vectors and two zero vectors are used to synthesize one desired vector. This will cause the three-phase switches to act in one synthesis, that is, the switches change between on and off, that is, the switch state changes between 0 and 1, and the three-phase switches change a total of 6 times in one synthesis.

[0063] DPWM uses only one zero vector in one synthesis, that is, it uses two adjacent vectors and one zero vector to synthesize one desired vector. Doing so will result in two phases of the three-phase switch switching in one synthesis, and one phase remains unchanged and remains on or off, that is, it is always 0 or always 1. In addition, it is worth noting that since there are two zero vectors and different sectors can use different zero vectors, there are many variants of DPWM. The following are three common zero vector selections: 1, all 6 sectors use zero vector V 0 (000). 2. All 6 sectors use zero vector V 7 (111). 3. The first, third, and fifth sectors use the zero vector V 0 (000), the second, fourth, and sixth sectors use the zero vector V7 (111).

[0064] It can be seen that in one synthesis, SVPWM needs to switch 6 times, while DPWM only needs to switch 4 times. The loss during switch switching causes heat, so DPWM can reduce the heat generation by about 1 / 3 compared with SVPWM.

[0065] like Figure 5 and Figure 6 Taking the three-phase waveform of the first quadrant as an example, we can intuitively see the difference between SVPWM and DPWM in the switching of three-phase switches in a desired vector synthesis. In SVPWM, all three-phase switches are switched; in DPWM, the U phase is always 1, and the switch does not switch.

[0066] In a vector synthesis, SVPWM has switching action in all three phases, while DPWM has switching action in two phases and one phase remains unchanged, so the heat generation is reduced by 1 / 3. However, 2PCDPWM can only have one phase switching action while the other two phases remain unchanged, so its heat generation is further reduced, by 2 / 3 compared with SVPWM and by 1 / 2 compared with DPWM.

[0067] The following takes the first sector as an example to introduce the principle of 2PCDPWM:

[0068] According to the basic principle of SVPWM, the vertices of six non-zero vectors are connected to form a regular hexagon, and the entire space is divided into six sectors, such as Figure 3 The first sector can be regarded as an equilateral triangle. If the angle bisectors of each angle of the triangle are drawn and intersected, the first sector can be divided into three parts, as shown in Figure 7 As shown, they are D1, D2, and D3 respectively.

[0069] like Figure 7 As shown in the figure, Vout is the voltage vector expected to be output in a synthesis, which can appear in any area inside the triangle. 2PCDPWM selects two corresponding vectors for approximate synthesis based on the area where Vout is located. The available vectors are two non-zero vectors and two zero vectors adjacent to the first sector. It is worth noting that 2PCDPWM uses two vectors for approximate synthesis, and there is an error between the synthesized vector and the expected vector. However, SVPWM and DPWM are both accurately synthesized, and the synthesized vector is the expected vector.

[0070] When Vout is in the D1 region, vectors V4 (100) and V0 (000) are used to synthesize, and the result is Vout1; when Vout is in the D2 region, vectors V6 (110) and V7 (111) are used to synthesize, and the result is Vout2; when Vout is in the D3 region, vectors V4 (100) and V6 (110) are used to synthesize, and the result is Vout3.

[0071] The principle of minimum synthesis error is adopted during synthesis, that is, when Vout is in the D1 area, Vout-Vout1 is required to be minimum, that is, the vector (Vout-Vout1) is perpendicular to the vector V4; when Vout is in the D2 area, Vout-Vout2 is required to be minimum, that is, the vector (Vout-Vout2) is perpendicular to the vector V6; when Vout is in the D3 area, Vout-Vou3 is required to be minimum, that is, the vector (Vout-Vout3) is perpendicular to the vector (V4-V6). It can also be understood that according to the area where Vout is located, a perpendicular line is drawn from Vout to the nearest triangle side, and the intersection of the triangle side and the perpendicular line is point C. The vector pointing from the origin to point C is the approximate synthetic vector with the minimum error.

[0072] According to the above description, the three-phase voltage waveform of 2PCDPWM in the three regions of the first sector can be obtained:

[0073] Depend on Figure 8-10 It can be seen that in one synthesis, only one phase of the three-phase switch has switching action, and two phases are always in the on or off state. Since the heat comes from the loss during the switching action, the heat generation of 2PCDPWM is reduced by 2 / 3 compared with SVPWM, and reduced by 1 / 2 compared with DPWM.

[0074] 2PCDPWM uses two vectors to approximately synthesize, and there is an error between the synthesized vector and the desired vector. However, SVPWM and DPWM are both accurately synthesized, and the synthesized vector is the desired vector. Although the error between the synthesized vector and the desired vector is minimized during vector synthesis, it always exists. The reaction to the controller is that the dynamic performance of the system deteriorates, the stability decreases, and the control accuracy decreases.

[0075] Solution:

[0076] 1. Choose the right usage scenario. The particularity of UAV aircraft is that the system cannot be stopped even if a fault occurs, otherwise the UAV may crash directly. When an overheating fault occurs, the motor controller must keep working even if the temperature exceeds the limit and continued operation will cause the temperature to rise further. If this method is used to drive the UAV, it means that even if the switching frequency is reduced and the DPWM algorithm is used, the controller temperature still reaches above 100°C, and the temperature may continue to rise. At this time, if 2PCDPWM is switched, since the heat generation of this algorithm is theoretically only half of that of DPWM, it can effectively reduce the heat generation of the controller and prevent the temperature from rising. At this time, ensuring that the controller does not cause the UAV to crash due to overheating and burning certain components is a higher priority than ensuring control performance. Moreover, when an overheating fault occurs, the control strategy of the UAV should be to hover in the air or land as soon as possible, and this strategy will not require too high control performance, which is lower than the performance requirements of various flight actions during normal flight.

[0077] 2. The errors caused by the algorithm can be compensated by the algorithm in other places. For example, you can first test the performance of the drone under the combination of 4 switching frequencies and wave modes, calculate the performance difference of 2PCDPWM, and add compensation to the appropriate part of the control algorithm to improve system performance and stability.

[0078] Example 2

[0079] An embodiment of the present invention further provides a control device of a low-heat UAV motor controller, comprising:

[0080] A monitoring module, which is used to obtain the real-time temperature of the motor controller;

[0081] The switching module receives the real-time temperature data of the motor controller sent by the acquisition module, determines the temperature range of the real-time temperature of the motor controller, and switches the wave generation mode and switching frequency of the inverter:

[0082] In this embodiment, a monitoring module and a switching module are provided in the control module of the motor driver;

[0083] The normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C;

[0084] When the real-time temperature of the motor controller is within the preset normal temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to 8kHz;

[0085] When the real-time temperature of the motor controller is in the preset medium-high temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to 6kHz;

[0086] When the real-time temperature of the motor controller is in the preset high temperature range, the inverter's wave generation mode is switched to DPWM, and the switching frequency is switched to 6kHz;

[0087] When the real-time temperature of the motor controller is within the preset over-temperature protection range, the inverter's wave generation mode is switched to 2PCDPWM and the switching frequency is switched to 6kHz.

[0088] Example 3

[0089] An embodiment of the present invention further provides a drone, comprising the above-mentioned control device.

[0090] Experimental verification

[0091] In order to verify the actual effect of the control method in Example 1 on the temperature of the UAV motor controller, an experiment was conducted to verify the effect.

[0092] Two experiments were conducted using a UAV powered tilt-rotor motor and a matching controller.

[0093] The parameters of the motor and controller are shown in Table 1 below:

[0094] Table 1 Parameters of motor and controller

[0095]

[0096] Test environment:

[0097] 1. Ambient temperature 25℃

[0098] 2. Motor shaft output speed 8000rpm

[0099] 3. The motor is placed on a towing test bench and loaded to the corresponding power to simulate the flight conditions of the UAV.

[0100] Experiment 1

[0101] Working mode:

[0102] A: Wave generation mode SVPWM, switching frequency 8k

[0103] B: SVPWM, switching frequency 6k

[0104] C: Wave generation mode DPWM, switching frequency 6k

[0105] The controller IGBT temperature is tested for 30 minutes in three working modes at different powers. If the temperature reaches 90°C, the test is stopped and the test time is recorded. The data of Experiment 1 are shown in Table 2 below:

[0106] Table 2 Experiment 1 data

[0107] Power(KW) A B C No load 33℃ 30℃ 27℃ 10 45℃ 39℃ 34℃ 20 61℃ 55℃ 44℃ 30 78℃ 70℃ 59℃ 35 86℃ 79℃ 68℃ 40 90℃(4min) 87℃ 76℃ 45 / 90℃(2min) 84℃ 50 / / 90℃(11min)

[0108] Experiment 2

[0109] Run the motor in working mode C, simulating a 50KW working condition, so that the controller temperature reaches 90°C, and then switch the wave mode from DPWM to 2PCDPWM, and the switching frequency remains unchanged. Record the IGBT temperature after running for 5 minutes. The data of Experiment 2 are shown in Table 2 below:

[0110] Table 2 Experiment 2 parameters

[0111] Time (min) Temperature(℃) 0 90 1 87 2 85 3 84 4 84 5 83

[0112] Summarize

[0113] 1. Experiment 1 verifies the effects of different wave generation modes and switching frequencies on IGBT heating. By switching different working modes according to different temperatures, heating can be effectively reduced without changing the controller output or affecting the motor operation by only modifying the software.

[0114] The 2.2PCDPWM wave generation method is not suitable for long-term control of motor operation due to its characteristics of approximate synthesis and difficulty in control. Due to its low heat generation characteristics, it is suitable for environments where the motor controller triggers over-temperature protection but still needs to continue to operate and is only used for a short time. Experiment 2 simulates the situation where the motor controller is overheated but still needs to continue to operate at high power when the drone is flying in the air. It can be seen that the output power is still maintained at 50kw, but the controller temperature is effectively reduced, and the duration also exceeds the typical operating conditions of drone flight. In addition, when a real drone encounters this situation, it will inevitably change its flight strategy to reduce power, such as changing to hovering in the air or vertical descent, which is conducive to the control of the 2PCDPWM wave generation method and reducing heat. Therefore, Experiment 2 verifies the feasibility of switching the 2PCDPWM wave generation method at high temperatures to reduce heat while maintaining the flight state of the drone.

[0115] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A control method for a low-heat UAV motor controller, characterized in that: The following steps are involved: Get the real-time temperature of the motor controller; Determine the temperature range of the motor controller's real-time temperature and switch the inverter's wave generation mode and switching frequency: When the real-time temperature of the motor controller is within the preset normal temperature range, the wave generation mode of the inverter is switched to SVPWM, and the switching frequency is switched to the first switching frequency; When the real-time temperature of the motor controller is in the preset medium-high temperature range, the inverter's wave generation mode is switched to SVPWM, and the switching frequency is switched to the second switching frequency; When the real-time temperature of the motor controller is within the preset high temperature range, the wave generation mode of the inverter is switched to DPWM, and the switching frequency is switched to the third switching frequency; When the real-time temperature of the motor controller is within the preset over-temperature protection interval, the wave generation mode of the inverter is switched to 2PCDPWM, and the switching frequency is switched to the fourth switching frequency.

2. The control method of a low-heat UAV motor controller according to claim 1, characterized in that: The normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C.

3. The control method of a low-heat UAV motor controller according to claim 1, characterized in that: The second switching frequency is not less than the first switching frequency, the third switching frequency is not less than the second switching frequency, and the fourth switching frequency is not less than the third switching frequency.

4. The control method of a low-heat UAV motor controller as claimed in claim 3, characterized in that: The first switching frequency is 8 kHz, the second switching frequency is 6 kHz, the third switching frequency is 6 kHz, and the fourth switching frequency is 6 kHz.

5. A control device for a low-heat UAV motor controller, characterized in that: include: A monitoring module, which is used to obtain the real-time temperature of the motor controller; The switching module receives the real-time temperature data of the motor controller sent by the acquisition module, determines the temperature range of the real-time temperature of the motor controller, and switches the wave generation mode and switching frequency of the inverter: When the real-time temperature of the motor controller is within the preset normal temperature range, the wave generation mode of the inverter is switched to SVPWM, and the switching frequency is switched to the first switching frequency; When the real-time temperature of the motor controller is in the preset medium-high temperature range, the wave generation mode of the inverter is switched to SVPWM, and the switching frequency is switched to the second switching frequency; When the real-time temperature of the motor controller is within the preset high temperature range, the wave generation mode of the inverter is switched to DPWM, and the switching frequency is switched to the third switching frequency; When the real-time temperature of the motor controller is within the preset over-temperature protection interval, the wave generation mode of the inverter is switched to 2PCDPWM, and the switching frequency is switched to the fourth switching frequency.

6. The control device of the low-heat UAV motor controller according to claim 5, characterized in that: The normal temperature range is below 60°C, the medium and high temperature range is [60, 80)°C, the high temperature range is [80, 100)°C, and the over-temperature protection range is above 100°C.

7. The control device of the low-heat UAV motor controller according to claim 5, characterized in that: The second switching frequency is not less than the first switching frequency, the third switching frequency is not less than the second switching frequency, and the fourth switching frequency is not less than the third switching frequency.

8. The control device of the low-heat UAV motor controller according to claim 7, characterized in that: The first switching frequency is 8 kHz, the second switching frequency is 6 kHz, the third switching frequency is 6 kHz, and the fourth switching frequency is 6 kHz.

9. A drone, characterized in that: Comprising a control device as described in any one of claims 5-8.

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