Methods, systems, media, and electronic devices for improving efficiency of a permanent magnet motor

Abstract

The application provides a method, system, medium and electronic equipment for improving the efficiency of a permanent magnet motor; a permanent magnet temperature determination method comprises the following steps: constructing an electromagnetic field model of the permanent magnet motor and setting an initial temperature of the permanent magnet; establishing a temperature field model of the permanent magnet motor, and simulating and calculating the highest temperature of the permanent magnet under a steady-state operating condition of the permanent magnet motor based on the temperature field model; performing parameterized scanning simulation on the permanent magnet temperature to respectively obtain the efficiency of the permanent magnet motor under different target working points corresponding to the permanent magnet temperature under different set temperatures; and obtaining the target temperature of the permanent magnet corresponding to the highest efficiency of the permanent magnet motor under each target working point according to the efficiency. The application provides a permanent magnet temperature determination method, which can improve the efficiency of the permanent magnet motor when applied to the permanent magnet motor, and the material cost remains unchanged, and the efficiency improvement effect is obvious.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, to a drive system, and in particular to a permanent magnet motor, specifically a method, system, medium and electronic equipment for improving the efficiency of a permanent magnet motor. Background Art

[0002] In order to achieve higher endurance, the drive system for new energy vehicles usually places high requirements on the efficiency of permanent magnet motors, especially the commonly used WLTC (World Light Vehicle Test Cycle) or CLTC (China Light Vehicle Test Cycle) operating efficiency. The traditional method on the market is to reduce copper and iron losses by optimizing the motor topology and improving the cooling conditions to ensure that the components of the permanent magnet motor maintain a low temperature throughout the entire operating range, so as to obtain better operating efficiency performance. At the same time, in order to obtain higher motor output torque, ensure the reliable operation of the permanent magnet motor, and avoid the risk of high-temperature demagnetization of the permanent magnet or over-temperature failure of the permanent magnet motor, the cooling conditions are continuously improved to make the permanent magnet work at the lowest temperature. However, in actual applications, when the permanent magnet is working at the lowest temperature, the efficiency of the corresponding permanent magnet motor is not necessarily the highest.

[0003] The prior art lacks a method for obtaining the temperature of a permanent magnet, so that the efficiency of the permanent magnet motor is highest when the permanent magnet of the permanent magnet motor operates at the permanent magnet temperature. Summary of the Invention

[0004] The object of the present invention is to provide a method, system, medium and electronic equipment for improving the efficiency of a permanent magnet motor, so as to solve the problems pointed out in the above background technology.

[0005] In a first aspect, the present invention provides a method for determining the temperature of a permanent magnet, which is applied to a permanent magnet motor; the method for determining the temperature of a permanent magnet comprises: constructing an electromagnetic field model of the permanent magnet motor and setting an initial temperature of the permanent magnet; establishing a temperature field model of the permanent magnet motor, and calculating the maximum temperature of the permanent magnet of the permanent magnet motor under steady-state operating conditions based on the temperature field model simulation; adjusting the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and performing a parametric sweep simulation on the permanent magnet temperature to obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures; the set temperature is greater than or equal to the initial temperature of the permanent magnet, and less than or equal to the maximum temperature of the permanent magnet; and obtaining the permanent magnet target temperature corresponding to the highest efficiency of the permanent magnet motor at each target operating point according to the efficiency.

[0006] The present invention provides a method for obtaining a target temperature of a permanent magnet that enables a permanent magnet motor to achieve the highest efficiency at various operating points, effectively solving the problems identified in the above background art.

[0007] In an implementation of the first aspect, each of the target operating points includes a rotational speed and a torque.

[0008] In an implementation of the first aspect, the permanent magnet temperature determination method further includes: drawing a temperature distribution diagram according to the permanent magnet target temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point.

[0009] In a second aspect, the present invention provides a permanent magnet temperature determination system, which is applied to a permanent magnet motor; the permanent magnet temperature determination system includes: a model construction module, which is used to construct an electromagnetic field model of the permanent magnet motor and set the initial temperature of the permanent magnet; a model construction module, which is used to establish a temperature field model of the permanent magnet motor, and to simulate and calculate the maximum temperature of the permanent magnet of the permanent magnet motor under steady-state operating conditions based on the temperature field model; a temperature simulation module, which is used to adjust the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and perform a parametric scanning simulation on the permanent magnet temperature to respectively obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures; the set temperature is greater than or equal to the initial temperature of the permanent magnet, and less than or equal to the maximum temperature of the permanent magnet; a temperature acquisition module, which is used to obtain the permanent magnet target temperature corresponding to the highest efficiency of the permanent magnet motor at each target operating point according to the efficiency.

[0010] In a third aspect, the present invention provides a method for improving the efficiency of a permanent magnet motor based on the above-mentioned permanent magnet temperature determination method. The method for improving the efficiency of a permanent magnet motor includes: obtaining the current operating condition point of the permanent magnet motor; obtaining the current temperature of the permanent magnet of the permanent magnet motor; and adjusting the cooling conditions of the permanent magnet motor based on the current temperature and the permanent magnet target temperature so that the permanent magnet operates at a temperature corresponding to the highest efficiency of the permanent magnet motor.

[0011] In the present invention, by applying the above-mentioned permanent magnet temperature determination method to a permanent magnet motor, the efficiency of the permanent magnet motor is improved without increasing the cost of the permanent magnet motor and without increasing the cost to improve the heat dissipation conditions of the permanent magnet motor.

[0012] In an implementation of the third aspect, obtaining the current temperature of the permanent magnet of the permanent magnet motor includes: when the current operating condition point is the same as one of the target operating conditions, obtaining the current temperature of the permanent magnet at the current operating condition point; adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: comparing the current temperature with the permanent magnet target temperature corresponding to the target operating point that is the same as the current operating condition point, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the permanent magnet target temperature corresponding to the target operating point that is the same as the current operating condition point.

[0013] In an implementation of the third aspect, obtaining the current temperature of the permanent magnet of the permanent magnet motor includes: obtaining the current temperature when obtaining the current operating condition point.

[0014] In an implementation of the third aspect, the cooling condition of the permanent magnet motor is adjusted based on the current temperature and the permanent magnet target temperature, including: determining the target operating point closest to the current operating condition point; comparing the current temperature with the permanent magnet target temperature corresponding to the target operating point closest to the current operating condition point, so that when the comparison result is inconsistent, the cooling condition is adjusted according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the permanent magnet target temperature corresponding to the target operating point closest to the current operating condition point.

[0015] In an implementation of the third aspect, the cooling condition of the permanent magnet motor is adjusted based on the current temperature and the permanent magnet target temperature, including: drawing a temperature distribution diagram based on the permanent magnet target temperature corresponding to the highest efficiency of the permanent magnet motor at each target operating point, and obtaining the fitting temperature corresponding to the highest efficiency of the permanent magnet motor at the current operating point through difference fitting; comparing the current temperature and the fitting temperature, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the fitting temperature.

[0016] In a fourth aspect, the present invention provides a system for improving the efficiency of a permanent magnet motor based on the above-mentioned method for determining the temperature of a permanent magnet. The system for improving the efficiency of a permanent magnet motor includes: a first acquisition module for acquiring the current operating condition point of the permanent magnet motor; a second acquisition module for acquiring the current temperature of the permanent magnet of the permanent magnet motor; and a cooling adjustment module for adjusting the cooling conditions of the permanent magnet motor based on the current temperature and the target temperature of the permanent magnet, so that the permanent magnet operates at a temperature corresponding to the highest efficiency of the permanent magnet motor.

[0017] In a fifth aspect, the present invention provides an electronic device, comprising: a processor and a memory; the memory is used to store a computer program; the processor is used to execute the computer program stored in the memory, so that the electronic device executes the above-mentioned method for determining the permanent magnet temperature, and / or the above-mentioned method for improving the efficiency of the permanent magnet motor.

[0018] In a sixth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by an electronic device, implements the above-mentioned method for determining the permanent magnet temperature and / or the above-mentioned method for improving the efficiency of a permanent magnet motor.

[0019] As described above, the method, system, medium, and electronic device for improving the efficiency of a permanent magnet motor according to the present invention have the following beneficial effects:

[0020] (1) Compared with the prior art, the present invention provides a method for determining the temperature of a permanent magnet. By applying the method to a permanent magnet motor and adjusting the cooling conditions of the permanent magnet motor according to the current operating condition of the permanent magnet motor, the permanent magnet of the permanent magnet motor is kept at the temperature with the highest efficiency (i.e., the target temperature of the permanent magnet). This method can improve the efficiency of the permanent magnet motor, keep the material cost unchanged, and significantly improve the efficiency. This solves the problem that the existing scheme design for improving the efficiency of the permanent magnet motor requires more expensive materials, increases the amount of component materials, increases the topological size, etc., which increases the cost of the permanent magnet motor.

[0021] (2) When adjusting the cooling conditions of the permanent magnet motor, if the temperature of the permanent magnet needs to be increased, the present invention only needs to weaken the cooling efficiency of the permanent magnet motor, without increasing the cost to improve the heat dissipation conditions, and can achieve real-time adjustment.

[0022] (3) The present invention ensures that the operating temperature of the permanent magnet is controlled within the maximum temperature of the permanent magnet, and does not increase the risk of overheating and demagnetization of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a flow chart of a method for determining the temperature of a permanent magnet according to an embodiment of the present invention.

[0024] Figure 2 Shown is a temperature distribution diagram according to an embodiment of the present invention.

[0025] Figure 3 Shown is an efficiency MAP diagram corresponding to the permanent magnet target temperature according to an embodiment of the present invention.

[0026] Figure 4 Shown is a structural schematic diagram of a permanent magnet temperature determination system according to an embodiment of the present invention.

[0027] Figure 5Shown is a flow chart of a method for improving the efficiency of a permanent magnet motor according to an embodiment of the present invention.

[0028] Figure 6 Shown is an efficiency MAP diagram corresponding to the initial temperature of the permanent magnet according to an embodiment of the present invention.

[0029] Figure 7 Display as Figure 3 and Figure 6 Efficiency difference diagram.

[0030] Figure 8 Shown is a structural schematic diagram of a system for improving the efficiency of a permanent magnet motor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0032] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0033] See Figures 1 to 8 . The following embodiments of the present invention provide methods, systems, media, and electronic devices for improving the efficiency of permanent magnet motors. Compared with the prior art, the present invention provides a method for determining the temperature of a permanent magnet. By applying the method to a permanent magnet motor and adjusting the cooling conditions of the permanent magnet motor according to the current operating point of the permanent magnet motor, the permanent magnet of the permanent magnet motor is at the temperature with the highest efficiency (i.e., the target temperature of the permanent magnet). This method can improve the efficiency of the permanent magnet motor without changing the material cost and significantly improving the efficiency. This solves the problem that the existing scheme for improving the efficiency of the permanent magnet motor requires more expensive materials, increased component material usage, and increased topological size, which increases the cost of the permanent magnet motor. When adjusting the cooling conditions of the permanent magnet motor, if it is necessary to increase the temperature of the permanent magnet, the present invention only needs to weaken the cooling efficiency of the permanent magnet motor without increasing the cost of improving the heat dissipation conditions, and can achieve real-time adjustment. The present invention ensures that the operating temperature of the permanent magnet is controlled within the maximum temperature of the permanent magnet, and does not increase the risk of overheating and demagnetization of the permanent magnet.

[0034] The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] like Figure 1 As shown, in one embodiment, the present invention provides a method for determining the temperature of a permanent magnet, which is applied to a permanent magnet motor.

[0036] Specifically, the method for determining the permanent magnet temperature includes:

[0037] Step S101: constructing an electromagnetic field model of the permanent magnet motor and setting an initial temperature of the permanent magnet.

[0038] It should be noted that the initial temperature of the permanent magnet is a preset temperature value, and its specific setting depends on at least but not limited to any one or two or more of the following factors: the material of the permanent magnet of the permanent magnet motor, the cooling structure of the permanent magnet motor and customer requirements, etc.; in actual applications, it can be set based on experience or objective conditions.

[0039] Step S102: establishing a temperature field model of the permanent magnet motor, and calculating the maximum temperature of the permanent magnets of the permanent magnet motor under steady-state operation conditions based on the temperature field model.

[0040] It should be noted that the steady-state operating condition of the motor refers to the state in which the motor's current, speed, torque and other parameters remain unchanged or fluctuate stably within a small allowable range under normal operating conditions. After the motor reaches the steady-state operating condition, the motor's operating parameters are stable, which can ensure the normal operation of the motor.

[0041] Step S103: adjusting the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and performing a parametric sweep simulation on the permanent magnet temperature to obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures.

[0042] In this embodiment, the set temperature is greater than or equal to the initial temperature of the permanent magnet and less than or equal to the maximum temperature of the permanent magnet.

[0043] It should be noted that the different set temperatures are not limiting conditions of the present invention; specifically, in practical applications, multiple different set temperatures can be selected between the initial temperature of the permanent magnet and the maximum temperature of the permanent magnet (including the initial temperature of the permanent magnet and the maximum temperature of the permanent magnet).

[0044] It should be noted that different target operating points are pre-selected, and the specific selection of the target operating point does not serve as a condition to limit the present invention. In actual applications, multiple different target operating points can be determined according to specific application scenarios.

[0045] It should be noted that, for the same set temperature, multiple different target operating points are selected; and for multiple different set temperatures, the multiple different target operating points selected are the same.

[0046] In one embodiment, each of the target operating points includes a speed and a torque.

[0047] The following further explains how the permanent magnet temperatures obtained in step S103 are at different set temperatures and how the efficiency of the permanent magnet motor at different target operating points corresponds to the permanent magnet temperatures obtained at different set temperatures through embodiments.

[0048] In one embodiment, T0 represents the initial temperature of the permanent magnet, T m Indicates the maximum temperature of the permanent magnet, between T0 and T m Select n different set temperatures, denoted as T1, T2…T i …T n (Add T0 and T m , there are n+2 set temperatures in total); where T i represents the i-th set temperature among n different set temperatures; the value of i ranges from 1 to n; k different target operating points are selected, which are recorded as (a1; b1), (a2; b2)…(a j ; b j )…(a k ; b k ); where a j represents the speed at the jth target operating point; b j represents the torque at the jth target operating point; j ranges from 1 to k, and the efficiency of the permanent magnet motor at different target operating points corresponding to the obtained T0 temperature is recorded as 、 … … ;in, It represents the efficiency of the permanent magnet motor at the jth target operating point at the temperature T0; corresponding to the obtained temperature T1, the efficiency of the permanent magnet motor at different target operating points is recorded as 、 … … ;in, It represents the efficiency of the permanent magnet motor at the jth target operating point at the temperature T1; the efficiency of the permanent magnet motor at different target operating points at the corresponding temperature T2 is recorded as 、 … … ;in, Indicates the efficiency of the permanent magnet motor at the jth target operating point at temperature T2; ... corresponds to the obtained T i At different temperatures, the efficiency of the permanent magnet motor at different target operating points is recorded as 、 … … ;in, Indicates that in T i Temperature, the efficiency of the permanent magnet motor at the jth target operating point...; the corresponding T n At different temperatures, the efficiency of the permanent magnet motor at different target operating points is recorded as 、 … … ;in, Indicates that in T n Temperature, the efficiency of the permanent magnet motor at the jth target operating point; the corresponding T m At different temperatures, the efficiency of the permanent magnet motor at different target operating points is recorded as 、 … … ;in, Indicates that in T m The efficiency of the permanent magnet motor at the jth target operating point at temperature.

[0049] In this embodiment, the values ​​of n and k (i.e., the number of set temperatures and the number of target operating points) are not used as conditions to limit the present invention. In actual applications, they can be determined according to specific application scenarios.

[0050] It should be noted that the acquisition of the above efficiency is output by the electromagnetic field model. The specific method of obtaining the efficiency adopts conventional technical means in the field, so its working principle will not be described in detail here.

[0051] Step S104 : obtaining, according to the efficiency, a target permanent magnet temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point.

[0052] Specifically, according to the efficiency obtained in step S103, the maximum efficiency of the permanent magnet motor at each target operating point is first determined; then, the temperature corresponding to the maximum efficiency is found, which is the target temperature of the permanent magnet.

[0053] In one embodiment, the permanent magnet target temperature may be the aforementioned T0, T1, T2...T i …T n 、T m Any one of .

[0054] Specifically, for each target operating point, there is an efficiency at different set temperatures. For example, in the above embodiment, at the first target operating point, there is an efficiency at T0, T1, T2...T i …T n 、T m The efficiency under 、 、 … … 、 ; Under the second target operating point, corresponding to T0, T1, T2…T i …T n 、T m The efficiency under 、 、 … … 、 ; ...At the jth target operating point, corresponding to T0, T1, T2...T i …T n 、T m The efficiency under 、 、 … … 、 ; ...Under the kth target operating point, corresponding to T0, T1, T2...T i …T n 、T m The efficiency under 、 、 … … 、 .

[0055] Correspondingly, for each target operating point, according to the above efficiency, find the i …T n 、T m The temperature corresponding to the highest efficiency under the condition of φ is the target temperature of the permanent magnet.

[0056] It should be noted that for different target operating points, the corresponding permanent magnet target temperatures may be the same or different.

[0057] like Figure 2 As shown, in one embodiment, the method for determining the permanent magnet temperature further includes: drawing a temperature distribution diagram according to the permanent magnet target temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point.

[0058] in, Figure 2 The horizontal axis represents the speed of the target operating point; the vertical axis represents the torque of the target operating point. Figure 2 Different colors in represent different temperature (i.e., permanent magnet target temperature) distributions.

[0059] like Figure 3 As shown, in one embodiment, the method for determining the permanent magnet temperature further includes: drawing an efficiency MAP diagram according to the maximum efficiency of the permanent magnet motor at each target operating point.

[0060] in, Figure 3 The horizontal axis represents the speed of the target operating point; the vertical axis represents the torque of the target operating point. Figure 3 Different colors in represent different efficiency (i.e., highest efficiency) distributions.

[0061] The protection scope of the permanent magnet temperature determination method described in the embodiment of the present invention is not limited to the execution order of the steps listed in this embodiment. All solutions implemented by adding, reducing, or replacing steps in the prior art based on the principles of the present invention are included in the protection scope of the present invention.

[0062] An embodiment of the present invention further provides a permanent magnet temperature determination system, which can implement the permanent magnet temperature determination method described in the present invention. However, the implementation device of the permanent magnet temperature determination method described in the present invention includes but is not limited to the structure of the permanent magnet temperature determination system listed in this embodiment. All structural deformations and replacements of the existing technology made according to the principles of the present invention are included in the protection scope of the present invention.

[0063] like Figure 4 As shown, in one embodiment, the present invention provides a permanent magnet temperature determination system, which is applied to a permanent magnet motor; the permanent magnet temperature determination system includes:

[0064] The model building module 401 is used to build the electromagnetic field model of the permanent magnet motor and set the initial temperature of the permanent magnet.

[0065] The model building module 402 is used to build a temperature field model of the permanent magnet motor, so as to simulate and calculate the maximum temperature of the permanent magnets of the permanent magnet motor under steady-state operation conditions based on the temperature field model.

[0066] The temperature simulation module 403 is used to adjust the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and perform a parametric sweep simulation on the permanent magnet temperature to obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures; the set temperature is greater than or equal to the initial temperature of the permanent magnet and less than or equal to the maximum temperature of the permanent magnet.

[0067] The temperature acquisition module 404 is configured to respectively acquire, based on the efficiency, a target permanent magnet temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point.

[0068] It should be noted that the structures and principles of the model construction module 401, the model establishment module 402, the temperature simulation module 403 and the temperature acquisition module 404 correspond one-to-one to the steps (steps S101 to S104) in the above-mentioned permanent magnet temperature determination method. The specific working principles can also be referred to the introduction of the permanent magnet temperature determination method in the above-mentioned embodiment, so they will not be repeated here.

[0069] It should be noted that the current designs for improving motor efficiency or improving motor cooling conditions, especially WLTC or CLTC operating efficiency, often increase motor cost at the expense of optimizing and adjusting the topology, increasing the amount of component materials, and selecting better silicon steel sheet materials and processes. This results in the need for more expensive materials, increased component material usage, and increased topology size, which is not cost-effective and has limited effect. At the same time, considering the extreme cost development trend of new energy drive systems, the conflict between motor material cost and operating efficiency requirements is becoming increasingly severe. There is an urgent need for a method that can improve the efficiency of permanent magnet motors without increasing costs. The present invention provides a new method for improving the efficiency of permanent magnet motors. Specifically, by applying the above-mentioned permanent magnet temperature determination method to the permanent magnet motor, the temperature of the permanent magnet is monitored and the cooling conditions of the permanent magnet motor are dynamically adjusted to achieve the improvement of the efficiency of the permanent magnet motor.

[0070] like Figure 5 As shown, in one embodiment, the present invention provides a method for improving the efficiency of a permanent magnet motor based on the above-mentioned method for determining the temperature of a permanent magnet. The method for improving the efficiency of a permanent magnet motor includes:

[0071] Step S501: Obtain the current operating condition point of the permanent magnet motor.

[0072] It should be noted that, in step S501, the current operating condition point of the permanent magnet motor is obtained by conventional technical means in this field, so it will not be described in detail here.

[0073] Step S502: Acquire the current temperature of the permanent magnet of the permanent magnet motor.

[0074] It should be noted that in step S502, the current temperature of the permanent magnet is obtained by conventional technical means in this field; for example, the current temperature can be estimated by monitoring the speed and induced electromotive force of the permanent magnet motor and comparing them with the back electromotive force at the reference temperature; the current temperature can also be estimated based on the operating parameters, thermal resistance parameters and coolant conditions of the permanent magnet motor by constructing a thermal network model of the thermal balance relationship between motor components such as the stator winding, stator core, rotor core, permanent magnet and the coolant.

[0075] Step S503: Adjust the cooling condition of the permanent magnet motor based on the current temperature and the target temperature of the permanent magnet, so that the permanent magnet operates at a temperature corresponding to the highest efficiency of the permanent magnet motor.

[0076] In one embodiment, obtaining the current temperature of the permanent magnet of the permanent magnet motor includes: when the current operating condition point is the same as one of the target operating conditions points, obtaining the current temperature of the permanent magnet at the current operating condition point.

[0077] Specifically, the current operating condition point of the permanent magnet motor is obtained through step S501, and step S502 is executed only when the current operating condition point is the same as one of the above-mentioned target operating conditions points, that is, the current temperature under the current operating condition point is obtained, that is, step S502 may be executed at the same time as step S501 (corresponding to the situation where the current operating condition point obtained in step S501 is exactly the same as a target operating condition point), or it may be executed after step S501 (corresponding to the situation where the current operating condition point obtained in step S501 is not the same as any target operating condition point. At this time, it can only wait until the next execution of step S501 to determine whether the current operating condition point obtained is the same as one of the target operating conditions points, and then decide whether to execute step S502).

[0078] In this embodiment, adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: comparing the current temperature with the permanent magnet target temperature corresponding to the target operating point that is the same as the current operating point, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result.

[0079] In this embodiment, the temperature corresponding to the highest efficiency of the permanent magnet motor is the target temperature of the permanent magnet corresponding to the target operating point that is the same as the current operating point.

[0080] In one embodiment, obtaining the current temperature of the permanent magnet of the permanent magnet motor includes: obtaining the current temperature when obtaining the current operating condition point.

[0081] Specifically, while the current operating condition point of the permanent magnet motor is obtained in step S501 , step S502 is executed to obtain the current temperature of the permanent magnet, that is, step S501 and step S502 are executed simultaneously.

[0082] In one embodiment, adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: determining the target operating point closest to the current operating condition point; comparing the current temperature with the permanent magnet target temperature corresponding to the target operating point closest to the current operating condition point, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result.

[0083] In this embodiment, the temperature corresponding to the highest efficiency of the permanent magnet motor is the target temperature of the permanent magnet corresponding to the target operating point closest to the current operating point.

[0084] In one embodiment, when determining the target operating point closest to the current operating point, the target operating point with the closest rotational speed or the target operating point with the closest torque may be selected.

[0085] In one embodiment, adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: drawing a temperature distribution diagram based on the permanent magnet target temperature corresponding to the highest efficiency of the permanent magnet motor at each target operating point, and obtaining the fitting temperature corresponding to the highest efficiency of the permanent magnet motor at the current operating point through difference fitting; comparing the current temperature and the fitting temperature, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result.

[0086] In this embodiment, the temperature corresponding to the highest efficiency of the permanent magnet motor is the fitting temperature.

[0087] In one embodiment, adjusting the cooling condition of the permanent magnet motor includes adjusting the cooling condition of a rotor of the permanent magnet motor.

[0088] It should be noted that the above temperature comparison can obtain two inconsistent comparison results. The first is: the current temperature is greater than the corresponding permanent magnet target temperature or fitting temperature; the second is: the current temperature is less than the corresponding permanent magnet target temperature or fitting temperature.

[0089] Specifically, when the comparison result is the first one, the rotor cooling efficiency is improved; when the comparison result is the second one, the rotor cooling efficiency is weakened.

[0090] It should be noted that the above-mentioned adjustment of the rotor cooling conditions adopts conventional technical means in this field; for example, the overall output cooling flow or the rotor cooling branch flow distribution can be adjusted by adjusting the valve opening of the flow control valve to increase or decrease the rotor cooling flow; the coolant temperature can also be adjusted by controlling whether the coolant is cooled by the radiator or adjusting the radiator working power through the temperature control reversing valve.

[0091] Specifically, when the comparison result is the first one, the coolant flow of the rotor branch should be increased, or the coolant temperature should be lowered; when the comparison result is the second one, the coolant flow of the rotor branch should be reduced, and the excess flow can be allocated to the stator to enhance the heat dissipation of the stator, thereby achieving the effect of reducing the stator copper loss and improving the efficiency of the motor at the same time, or increasing the rotor coolant temperature. However, in order to avoid the stator cooling being weakened at the same time and causing the stator copper loss to increase, only the coolant temperature of the rotor branch should be increased.

[0092] It should be noted that the coolant flow rate range and temperature range should be adjusted within the total flow rate range and temperature range of the initial system design, and until the actual permanent magnet temperature is closest to the corresponding permanent magnet target temperature.

[0093] The working principle of the method for improving the efficiency of a permanent magnet motor of the present invention is further explained below through specific embodiments.

[0094] In one embodiment, based on motor performance, topology index requirements, and cost targets, a topology optimization scheme is performed to obtain an electromagnetic field model and a temperature field model of the permanent magnet motor.

[0095] The motor efficiency MAP corresponding to the optimal heat dissipation capacity can be achieved according to the cooling conditions of the permanent magnet motor rotor. The motor efficiency MAP specified by the operation or assembly is simulated using the permanent magnet initial temperature T0. The material properties corresponding to the permanent magnet initial temperature T0 are set in the electromagnetic field model.

[0096] In this embodiment, a permanent magnet motor solution with a coolant temperature of 80° C. and a flow rate of 8 L / min is taken as an example, and the initial temperature T0 of the permanent magnet used in the simulation is 80° C.

[0097] Establish a temperature field model and simulate and calculate the maximum temperature T of the permanent magnet of the permanent magnet motor under all required continuous steady-state operating conditions. m is 140℃.

[0098] Adjust the permanent magnet temperature in the electromagnetic field model and set it to be greater than or equal to the initial temperature T0 (80°C) and less than or equal to the maximum temperature T m (140℃), and perform parametric sweep simulation on the permanent magnet temperature.

[0099] In this embodiment, the permanent magnet temperature is scanned at intervals of 10° C. to obtain efficiency data within the motor peak torque and maximum operating speed at different set temperatures of 80° C., 90° C., 100° C., …, and 140° C.

[0100] For each torque-speed operating point of the permanent magnet motor (i.e., corresponding to the target operating point), based on the efficiency data corresponding to the above-mentioned different permanent magnet temperatures, the data with the highest efficiency is selected, and the corresponding permanent magnet temperature is recorded, i.e., corresponding to the above-mentioned permanent magnet target temperature.

[0101] like Figure 3 As shown in , the highest efficiency of all operating points is summarized into an efficiency MAP diagram, and the permanent magnet target temperature distribution matrix with the highest efficiency at each operating point is obtained, as shown in Figure 2 shown.

[0102] When the permanent magnet motor is running, obtain the current temperature of the permanent magnet.

[0103] It is assumed in this embodiment that the current operating point is the same as the target operating point.

[0104] The permanent magnet target temperature corresponding to the current operating condition point is queried among the most efficient permanent magnet target temperatures, and the current temperature is compared to see whether it is consistent with the permanent magnet target temperature.

[0105] If the current temperature is inconsistent with the permanent magnet target temperature, the rotor cooling condition is dynamically adjusted until the actual permanent magnet temperature is at the permanent magnet target temperature; specifically, if the current temperature is lower than the permanent magnet target temperature, the rotor cooling condition is weakened; if the current temperature is higher than the permanent magnet target temperature, the rotor cooling condition is strengthened.

[0106] like Figure 6 As shown, it shows the efficiency MAP diagram when the permanent magnet temperature is the permanent magnet initial temperature T0 (80°C), using the permanent magnet target temperature distribution matrix of the present invention ( Figure 2 ) of the highest efficiency distribution ( Figure 3 ) Compared with it, the efficiency improvement is as follows Figure 7 shown.

[0107] Depend on Figure 7 It can be seen that in the low-speed, low-torque and medium-high-speed, medium-torque regions, increasing the operating temperature of the permanent magnets can effectively improve the motor efficiency in these regions. The single-point efficiency can be improved by more than 5%, and the proportion of the high-efficiency area increases from 85.9% to 87.2%. The operating efficiency improvement effect is shown in Table 1 below.

[0108] Table 1

[0109] .

[0110] The present invention provides a method for improving the efficiency of a permanent magnet motor. The method adjusts the cooling conditions of the permanent magnet motor rotor according to the actual operating condition point of the permanent magnet motor so that the permanent magnet operates at a corresponding temperature to achieve the highest efficiency of the permanent magnet motor. The material cost of this method remains unchanged, and the efficiency improvement effect is obvious. Technically, only an adjustable control strategy for rotor cooling is required, which will not lead to an increase in the cost of the motor, and there is no need to increase the cost of improving the heat dissipation conditions, and real-time adjustment can be achieved. At the same time, it ensures that the operating temperature of the permanent magnet is controlled within the maximum temperature of the permanent magnet, and the risk of overheating and demagnetization of the permanent magnet is not increased.

[0111] An embodiment of the present invention also provides a system for improving the efficiency of a permanent magnet motor. The system for improving the efficiency of a permanent magnet motor can implement the method for improving the efficiency of a permanent magnet motor described in the present invention. However, the implementation device of the method for improving the efficiency of a permanent magnet motor described in the present invention includes but is not limited to the structure of the system for improving the efficiency of a permanent magnet motor listed in this embodiment. All structural deformations and replacements of the prior art made according to the principles of the present invention are included in the protection scope of the present invention.

[0112] like Figure 8 As shown, in one embodiment, the present invention provides a system for improving the efficiency of a permanent magnet motor based on the above-mentioned method for determining the temperature of a permanent magnet. The system for improving the efficiency of a permanent magnet motor includes:

[0113] The first acquisition module 801 is used to acquire the current operating condition point of the permanent magnet motor.

[0114] The second acquisition module 802 is configured to acquire the current temperature of the permanent magnet of the permanent magnet motor.

[0115] The cooling adjustment module 803 is configured to adjust the cooling condition of the permanent magnet motor based on the current temperature and the target temperature of the permanent magnet, so that the permanent magnet operates at a temperature corresponding to the highest efficiency of the permanent magnet motor.

[0116] It should be noted that the structures and principles of the first acquisition module 801, the second acquisition module 802 and the cooling adjustment module 803 correspond one-to-one to the steps (steps S501 to S503) in the above-mentioned method for improving the efficiency of the permanent magnet motor. The specific working principles can also be referred to the introduction of the method for improving the efficiency of the permanent magnet motor in the above-mentioned embodiment, so they will not be repeated here.

[0117] An embodiment of the present invention also provides an electronic device, comprising: a processor and a memory; the memory is used to store a computer program; the processor is used to execute the computer program stored in the memory, so that the electronic device executes the above-mentioned method for determining the permanent magnet temperature and / or the above-mentioned method for improving the efficiency of a permanent magnet motor.

[0118] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, which, when executed by an electronic device, implements the above-mentioned method for determining the permanent magnet temperature and / or the above-mentioned method for improving the efficiency of a permanent magnet motor.

[0119] Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments can be performed by instructing a processor through a program. The program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as random access memory, read-only memory, flash memory, a hard disk, a solid-state drive, a magnetic tape, a floppy disk, an optical disc, or any combination thereof. The storage medium can be any available medium accessible by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital video disc (DVD)), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0120] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices or methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of modules / units is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules or units, which can be electrical, mechanical or other forms.

[0121] Modules / units described as separate components may or may not be physically separate, and components displayed as modules / units may or may not be physical modules, that is, they may be located in one place or distributed across multiple network elements. Some or all of the modules / units may be selected based on actual needs to achieve the objectives of the embodiments of the present invention. For example, the functional modules / units in various embodiments of the present invention may be integrated into a single processing module, each module / unit may exist physically separately, or two or more modules / units may be integrated into a single module / unit.

[0122] Those skilled in the art should further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0123] The descriptions of the processes or structures corresponding to the above figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0124] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for improving the efficiency of a permanent magnet motor, characterized in that: The method for improving the efficiency of a permanent magnet motor comprises: Get the current operating condition of the permanent magnet motor; Acquire the current temperature of the permanent magnet of the permanent magnet motor; adjusting the cooling condition of the permanent magnet motor based on the current temperature and a target permanent magnet temperature so that the permanent magnet operates at a temperature corresponding to when the efficiency of the permanent magnet motor is highest; the target permanent magnet temperature is obtained based on a permanent magnet temperature determination method; The method for determining the permanent magnet temperature comprises: Constructing an electromagnetic field model of the permanent magnet motor and setting an initial temperature of the permanent magnet; Establishing a temperature field model of the permanent magnet motor to simulate and calculate the maximum temperature of the permanent magnets of the permanent magnet motor under steady-state operating conditions based on the temperature field model; adjusting the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and performing a parametric sweep simulation on the permanent magnet temperature to obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures; the set temperature is greater than or equal to the initial temperature of the permanent magnet and less than or equal to the maximum temperature of the permanent magnet; The permanent magnet target temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point is obtained according to the efficiency.

2. The method for improving the efficiency of a permanent magnet motor according to claim 1, characterized in that: Each of the target operating points includes a speed and a torque.

3. The method for improving the efficiency of a permanent magnet motor according to claim 1, wherein: The method for determining the permanent magnet temperature further includes: drawing a temperature distribution diagram according to the permanent magnet target temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point.

4. The method for improving the efficiency of a permanent magnet motor according to claim 1, wherein: The obtaining of the current temperature of the permanent magnet of the permanent magnet motor comprises: when the current operating condition point is the same as one of the target operating conditions points, obtaining the current temperature of the permanent magnet at the current operating condition point; The method of adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: comparing the current temperature with the permanent magnet target temperature corresponding to the target operating point that is the same as the current operating point, and when the comparison result is inconsistent, adjusting the cooling condition according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the permanent magnet target temperature corresponding to the target operating point that is the same as the current operating point.

5. The method for improving the efficiency of a permanent magnet motor according to claim 1, characterized in that: The obtaining of the current temperature of the permanent magnet of the permanent magnet motor includes: obtaining the current temperature when obtaining the current operating condition point.

6. The method for improving the efficiency of a permanent magnet motor according to claim 5, characterized in that: The step of adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: Determining a target operating point that is closest to the current operating point; Compare the current temperature with the permanent magnet target temperature corresponding to the target operating point closest to the current operating condition point, and when the comparison result is inconsistent, adjust the cooling condition according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the permanent magnet target temperature corresponding to the target operating point closest to the current operating condition point.

7. The method for improving the efficiency of a permanent magnet motor according to claim 5, characterized in that: The step of adjusting the cooling condition of the permanent magnet motor based on the current temperature and the permanent magnet target temperature includes: According to the target permanent magnet temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point, a temperature distribution diagram is drawn, and the fitting temperature corresponding to the maximum efficiency of the permanent magnet motor at the current operating point is obtained by difference fitting; The current temperature and the fitting temperature are compared, and when the comparison result is inconsistent, the cooling condition is adjusted according to the comparison result; the temperature corresponding to the highest efficiency of the permanent magnet motor is the fitting temperature.

8. A system for improving the efficiency of a permanent magnet motor, characterized in that: The system for improving the efficiency of a permanent magnet motor comprises: The first acquisition module is used to obtain the current operating condition point of the permanent magnet motor; A second acquisition module is used to acquire the current temperature of the permanent magnet of the permanent magnet motor; a cooling adjustment module, configured to adjust the cooling conditions of the permanent magnet motor based on the current temperature and a target permanent magnet temperature, so that the permanent magnet operates at a temperature corresponding to when the permanent magnet motor has the highest efficiency; the target permanent magnet temperature is obtained based on a permanent magnet temperature determination method; The method for determining the permanent magnet temperature comprises: Constructing an electromagnetic field model of the permanent magnet motor and setting an initial temperature of the permanent magnet; Establishing a temperature field model of the permanent magnet motor to simulate and calculate the maximum temperature of the permanent magnets of the permanent magnet motor under steady-state operating conditions based on the temperature field model; adjusting the permanent magnet temperature of the permanent magnet motor based on the temperature field model and the electromagnetic field model, and performing a parametric sweep simulation on the permanent magnet temperature to obtain the efficiency of the permanent magnet motor at different target operating points corresponding to the permanent magnet temperature at different set temperatures; the set temperature is greater than or equal to the initial temperature of the permanent magnet and less than or equal to the maximum temperature of the permanent magnet; The permanent magnet target temperature corresponding to the maximum efficiency of the permanent magnet motor at each target operating point is obtained according to the efficiency.

9. An electronic device, characterized in that: The electronic device includes: a processor and a memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so as to enable the electronic device to perform the method for improving the efficiency of a permanent magnet motor according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by an electronic device, the method for improving the efficiency of a permanent magnet motor according to any one of claims 1 to 7 is implemented.

Images