Sequence number	Preset operating current (a)	Preset duration (min)
			1	I0	90
2	1.1*I0	60
			3	1.2*I0	30
4	1.3*I0	18
			5	1.4*I0	12
6	1.5*I0	8
			7	1.6*I0	5
8	1.7*I0	4
			9	1.8*I0	3
10	1.9*I0	2
			11	2.0*I0	1

Wherein I0 is the rated current of the motor, the specific meaning of Table 1 is that when the inlet temperature is lower than 55 ℃,

When the working current of the motor is rated current I0, the motor can always operate according to the rated current according to the normal condition, but in reality, the motor cannot operate with a large load for a long time, so if the motor operates with the rated current for a long time exceeding 90min continuously, the motor is overloaded;

when the working current of the motor is 1.1 x I0 and the duration exceeds 60min, the motor is overloaded;

when the working current of the motor is 1.2 x I0 and the duration exceeds 30min, the motor is overloaded;

when the working current of the motor is 1.3 x I0 and the duration exceeds 18min, the motor is overloaded;

When the working current of the motor is 1.4 x I0 and the duration exceeds 12min, the motor is overloaded;

when the working current of the motor is 1.5 x I0 and the duration exceeds 8min, the motor is overloaded;

When the working current of the motor is 1.6I0 and the duration exceeds 5min, the motor is overloaded;

When the working current of the motor is 1.7 x I0 and the duration exceeds 4min, the motor is overloaded;

When the working current of the motor is 1.8I0 and the duration exceeds 3min, the motor is overloaded;

When the working current of the motor is 1.9 x I0 and the duration exceeds 2min, the motor is overloaded;

When the motor operating current is 2.0 x 0 and the duration exceeds 1min, the motor is overloaded.

At an inlet temperature below 55 ℃, the preset operating current of the motor and the preset duration corresponding to the preset operating current are shown in table 2.

TABLE 2

Sequence number	Preset operating current (a)	Preset duration (min)
			1	I0	60
2	1.1*I0	45
			3	1.2*I0	25
4	1.3*I0	15
			5	1.4*I0	10
6	1.5*I0	4
			7	1.6*I0	3
8	1.7*I0	2
			9	1.8*I0	1
10	1.9*I0	0.5
			11	2.0*I0	0.1

Wherein, the specific meaning of the table2 is that when the inlet temperature is higher than 55 ℃,

When the working current of the motor is rated current I0, and the cooling water temperature is higher, if the motor runs at the rated current for longer time than 60 minutes, the motor is overloaded;

when the working current of the motor is 1.1 x I0 and the duration exceeds 45min, the motor is overloaded;

When the working current of the motor is 1.2 x I0 and the duration exceeds 25min, the motor is overloaded;

when the working current of the motor is 1.3 x I0 and the duration exceeds 15min, the motor is overloaded;

When the working current of the motor is 1.4 x I0 and the duration exceeds 10min, the motor is overloaded;

When the working current of the motor is 1.5 x I0 and the duration exceeds 4min, the motor is overloaded;

When the working current of the motor is 1.6I0 and the duration exceeds 3min, the motor is overloaded;

when the working current of the motor is 1.7 x I0 and the duration exceeds 2min, the motor is overloaded;

When the working current of the motor is 1.8I0 and the duration exceeds 1min, the motor is overloaded;

when the working current of the motor is 1.9 x I0 and the duration exceeds 0.5min, the motor is overloaded;

when the motor operating current is 2.0 x 0 and the duration exceeds 0.1min, the motor is overloaded.

It should be noted that, in the above example, two temperature intervals are divided by 55 ℃, or may be divided into N temperature intervals according to different temperature gradients, and the two temperature intervals are controlled by N preset working currents and preset durations, which are the same in principle and are not described here again.

For example, referring to table 1, when the inlet temperature is in a temperature interval lower than 55 ℃, the corresponding preset duration is 60min when the preset operating current is 1.1×i0, and the corresponding preset duration is 30min when the preset operating current is 1.2×i0, i.e., the larger the preset operating current is in the same temperature interval, the shorter the corresponding preset duration is. The same trend is also shown in table 2.

For example, referring to tables 1 and 2, when the preset operating current is 1.1×i0, the preset duration corresponding to the temperature interval below 55 ℃ is 60min, and the preset duration corresponding to the temperature interval above 55 ℃ is 45min, i.e. the higher the temperature, the shorter the corresponding preset duration.

Specifically, the specific value of the preset working current is determined according to the external characteristics of the motor, namely, the MAP diagram, is tested under different temperature ranges, the overload point is selected on the edge of the overload curve according to the MAP diagram, the current value of the preset working current is converted according to the torque value of the overload point, and the preset duration is obtained through simulation or test according to the time (motor overload capacity) required by the motor system to reach the heat balance.

According to one embodiment of the invention, overload control and/or overload protection is performed on the motor according to the actual duration and the preset duration, wherein the overload control and/or overload protection comprises the steps of reducing the actual working current of the motor when the actual duration reaches the preset time before the preset duration, and/or controlling the motor to run in a power-down mode when the actual duration reaches the preset duration, and sending out overload reminding information. The preset time can be calibrated according to actual conditions.

Further, according to one embodiment of the invention, controlling the motor to run at reduced power includes reducing the output torque of the motor.

Specifically, when the actual working current is the preset working current, the motor controller compares the actual duration with the preset duration corresponding to the preset working current, and when the actual duration is smaller than the preset duration, that is, when the time that the motor works with the preset working current has not reached the preset duration, the actual working current of the motor can be reduced when the actual duration reaches the remaining preset time of the preset duration, so as to perform overload control. Taking table 1 as an example, when the actual working current of the motor is 1.4×i0 and the corresponding preset duration is 12min, and when the actual duration of the motor running at the working current of 1.4×i0 reaches 11min56s, the preset time is 4s, the actual working current of the motor is controlled to be reduced by one level, namely, to be reduced to 1.3×i0, and so on. Therefore, the overload protection can be controlled by controlling the motor in an overload way, and the overload capacity of the motor can be exerted as much as possible at the same time of not triggering the overload protection.

When the actual duration is greater than or equal to the preset duration, that is, when the time that the motor works with the preset working current reaches the preset duration, the motor is overloaded, in order to protect the motor, the motor needs to be overload-protected, the motor controller can control the motor to reduce the output torque so as to limit the output power of the motor, and a reminding message of the overload of the motor is sent out. Continuing to take table 1 as an example, when the actual working current of the motor is 1.4×i0 and the corresponding preset duration is 12min, when the actual duration of the motor running at the working current of 1.4×i0 exceeds 12min, the motor controller may control the motor to reduce the output torque, so that the output power of the motor is rapidly reduced by 50%, and after the output torque of the motor is reduced, the rotation speed of the motor is gradually reduced, and the rotation speed of the motor is not suddenly changed, thereby ensuring the use safety of the motor. For example, when the motor is a main drive motor of an electric automobile, overload protection is carried out on the main drive motor, the main drive motor is controlled to run in a power-down mode, the output torque of the main drive motor is reduced, the rotating speed of the main drive motor is gradually reduced in the process after the torque is reduced, so that the rotating speed of the main drive motor is prevented from being suddenly changed, the speed of the whole automobile is prevented from being suddenly changed, and the running safety of the whole automobile is ensured.

Further, in order to quickly protect the motor, when the motor has been operated for a preset duration with a preset operating current, the motor controller may also control the motor to perform overload protection while controlling the motor to perform overload control, i.e. the motor controller may appropriately reduce the operating current of the motor while controlling the motor to reduce the output torque. Therefore, the motor can be quickly separated from the overload state, and the motor is prevented from being damaged.

It should be understood that the inlet temperature of the cooling liquid is changed at time, and two temperature intervals divided by 55 ℃ are taken as an example continuously, so as to avoid factors such as jump or error in the process of temperature acquisition, and therefore, when the inlet temperature of the cooling liquid of the motor is higher or lower than 55 ℃, the time period constraint condition is added, namely, the instant judgment basis is that the duration time period of continuous detection is more than 5 seconds when the inlet temperature of the cooling liquid of the motor is higher or lower than 55 ℃. When the motor is controlled under the overload condition with the temperature higher than 55 ℃, if the inlet temperature of the motor cooling liquid is lower than 55 ℃ and the continuous detection duration period is longer than 5 seconds, the control mode when the inlet temperature is lower than 55 ℃ is automatically started, and when the motor is controlled under the overload condition with the temperature lower than 55 ℃, if the inlet temperature of the motor cooling liquid is higher than 55 ℃ and the continuous detection duration period is longer than 5 seconds, the control mode when the inlet temperature is higher than 55 ℃ is automatically started.

In summary, according to the motor control method of the embodiment of the present invention, the actual working current of the current motor, the actual duration corresponding to the actual working current, and the inlet temperature of the cooling liquid are obtained first, then the preset working current of the motor and the preset duration corresponding to the preset working current are determined according to the inlet temperature, and when the actual working current is the preset working current, overload control and/or overload protection are performed on the motor according to the actual duration and the preset duration. Therefore, the method can timely protect the motor from overload, ensure the service life of the motor, enable the motor to fully exert the overload capacity of the motor, enable the motor to work in a high-efficiency area and improve the economical efficiency.

Corresponding to the embodiment, the invention also provides a motor controller.

Fig. 2 is a block schematic diagram of a motor controller according to an embodiment of the present invention.

As shown in fig. 2, the motor controller 200 according to the embodiment of the present invention includes a memory 210, a processor 220, and a program stored in the memory 210 and executable on the processor 220, and when the processor 220 executes the program, the motor control method described above is implemented.

Corresponding to the embodiment, the invention also provides a motor control device.

Fig. 3 is a block schematic diagram of a motor control device according to an embodiment of the present invention.

As shown in fig. 3, in the motor control device 100 according to the embodiment of the present invention, the motor is cooled by the coolant, and the device 100 may include an acquisition module 110, a determination module 120, and a control module 130.

The acquiring module 110 is configured to acquire an actual operating current of the present motor, an actual duration corresponding to the actual operating current, and an inlet temperature of the cooling liquid. The determining module 120 is configured to determine an overload parameter of the motor according to the inlet temperature, where the overload parameter includes a preset operating current and a preset duration corresponding to the preset operating current. The control module 130 is configured to perform overload control and/or overload protection on the motor according to the actual duration and the preset duration when the actual working current is the preset working current.

According to one embodiment of the present invention, the determining module 120 is configured to determine an overload parameter of the motor according to the inlet temperature, and specifically configured to obtain a temperature interval corresponding to the inlet temperature, and determine the overload parameter according to the temperature interval, where different temperature intervals correspond to different overload parameters.

According to one embodiment of the invention, the control module 130 performs overload control and/or overload protection on the motor according to the actual duration and the preset duration, and is specifically configured to reduce the actual working current of the motor when the actual duration reaches the preset time before the preset duration, and/or control the motor to run at reduced power when the actual duration reaches the preset duration, and send out overload reminding information.

According to one embodiment of the invention, the control module 130 controls the motor to run at reduced power, in particular for reducing the output torque of the motor.

It should be noted that, for details not disclosed in the motor control device in the embodiment of the present invention, please refer to details disclosed in the motor control method in the embodiment of the present invention, and details are not described here again.

Corresponding to the embodiment, the invention also provides a vehicle.

According to one embodiment of the present invention, as shown in fig. 4, a vehicle 300 includes the motor controller 200 described above.

According to another embodiment of the present invention, as shown in fig. 5, a vehicle 300 includes the motor control device 100 described above.

It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, for example, may be considered as a ordered listing of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include an electrical connection (an electronic device) having one or more wires, a portable computer diskette (a magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of techniques known in the art, discrete logic circuits with logic gates for implementing logic functions on data signals, application specific integrated circuits with appropriate combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, directly connected, indirectly connected through an intervening medium, or in communication between two elements or in an interaction relationship between two elements, unless otherwise explicitly specified. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.