Temperature estimation method and device of motor, electronic equipment and storage medium

Abstract

The invention discloses a motor temperature estimation method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring a corresponding balance current threshold value when the balance temperature of the motor reaches a preset limit temperature; judging the relationship between the input current of the motor and the balance current threshold value, and acquiring a heat capacity parameter of the motor under the input current; if the current of the motor is greater than the balance current threshold, calculating the accumulated heat capacity of the motor according to the heat capacity parameter and a first preset formula; if the current of the motor is smaller than or equal to the balance current threshold value, the accumulated heat capacity of the motor is calculated according to the heat capacity parameter and a second preset formula; wherein the accumulated heat capacity is greater than or equal to 0 and less than or equal to 1; and estimating the temperature of the motor according to the accumulated heat capacity and a third preset formula. According to the invention, high-accuracy estimation can be carried out on the temperature of the motor at low cost.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method, device, electronic equipment and storage medium for estimating the temperature of a motor. Background Art

[0002] Motors have important applications in many technical fields, such as vehicles. For example, the permanent magnet synchronous motor (PMSM) is an important actuator of the electric power steering (EPS) system of automobiles. Usually, the field oriented control (FOC) strategy is adopted to complete the current control of the PMSM and make it output the corresponding electromagnetic torque to provide corresponding assistance for the EPS system. During the operation of the EPS system, if the motor continues to work under high current conditions for a long time, the internal temperature of the motor will rise sharply, causing the insulation strength of the enameled wire inside the motor to decrease, causing the motor to be damaged, and directly affecting the driver's life safety. Therefore, it is necessary to monitor the temperature of the motor and design the corresponding motor thermal protection algorithm accordingly to ensure the safety and reliability of the motor during the operation of the EPS system.

[0003] In the related art, the temperature monitoring and thermal protection methods for permanent magnet synchronous motors in EPS systems can generally include four methods. Method one is a method using power loss estimation. This method estimates the power loss of the motor through the working current and working time when the motor is running. When the power loss reaches the set threshold, the motor is protected from overheating. Method two is a method using a temperature sensor. A temperature sensor is added to the motor winding end to directly measure the temperature change during the operation of the motor. Once the temperature exceeds the set threshold, the motor is protected from overheating. Method three is an indirect monitoring method. Through a thermistor, the temperature of the MOSFET or controller is monitored to indirectly estimate the motor temperature, and an overheat protection algorithm is designed accordingly. Method four is an end protection method. This method can effectively protect the mechanical structure of the EPS system and indirectly achieve thermal protection of the motor.

[0004] However, in method 1, the temperature rise of the motor is estimated by power loss. Since the internal resistance of the motor changes with temperature, the nonlinearity of the resistance needs to be considered in the power loss calculation process. Otherwise, there is a large error between the calculated power loss and the actual power loss, resulting in a large difference between the estimated motor temperature and the actual temperature. In method 2, a temperature sensor is installed at the motor winding end, which increases the complexity of the system hardware design, puts forward higher requirements for the functional safety of the EPS system, and further increases the development cost of the system. In method 3, the temperature of the controller or MOSFET is measured by a thermistor and is equivalent to the motor temperature. Due to the large difference between the temperature rise characteristics of other components and the motor, the obtained motor temperature has a large deviation from its actual temperature. The end protection method of method 4 can effectively protect the mechanical structure of the EPS system and achieve the purpose of protecting the motor by reducing the output. However, this method cannot protect the system from instability caused by the excessive temperature rise of the motor itself. Therefore, it is urgent to propose a low-cost and high-accuracy temperature estimation method. Summary of the invention

[0005] The present invention provides a method, a device, an electronic device and a storage medium for estimating the temperature of a motor, which can estimate the temperature of the motor with high accuracy at low cost.

[0006] According to one aspect of the present invention, a method for estimating temperature of a motor is provided, comprising:

[0007] Obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature;

[0008] Determining the relationship between the input current of the motor and the balancing current threshold, and obtaining the thermal capacity parameter of the motor under the input current;

[0009] If the current of the motor is greater than the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and a first preset formula; if the current of the motor is less than or equal to the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and a second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1;

[0010] The temperature of the motor is estimated according to the accumulated heat capacity and a third preset formula.

[0011] Optionally, obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature includes:

[0012] Reading a balancing current threshold of the motor;

[0013] And / or, the obtaining of a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature includes:

[0014] Inputting a first preset current into a test motor to determine a balance temperature of the test motor;

[0015] The first preset current is adjusted until the equilibrium temperature of the test motor reaches the preset limit temperature; and the first preset current is used as the equilibrium current threshold.

[0016] Optionally, obtaining a thermal capacity parameter of the motor under the input current includes:

[0017] Obtaining a corresponding relationship between the temperature and time of the motor under the input current, and determining the heat capacity parameter according to the corresponding relationship between the temperature and time;

[0018] If the input current is greater than the balancing current threshold, the thermal capacity parameters include: the temperature rise time T from the initial temperature to the preset limit temperature trip , a first proportionality coefficient K, wherein the proportionality coefficient K is the difference between the preset limit temperature and the initial temperature;

[0019] If the input current is less than or equal to the balancing current threshold, the thermal capacity parameter includes: a second proportional coefficient TCU END , time constant τ and the first proportional coefficient K; wherein the second proportional coefficient TCU END The difference between the equilibrium temperature corresponding to the input current and the initial temperature is divided by the difference between the preset limit temperature and the initial temperature.

[0020] Optionally, the first preset formula is:

[0021]

[0022] Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δt-th calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0023] Optionally, the second preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δt-th calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0024] Optionally, the third preset formula is:

[0025] Temp(k·Δt)=TCU(k·Δt)×K+Temp(0);

[0026] Wherein, Temp(k·Δt) is the estimated temperature of the motor in the k·Δt-th calculation cycle, and Temp(0) is the initial temperature of the motor.

[0027] Optionally, obtaining the corresponding relationship between the temperature of the motor under the input current and the time includes:

[0028] Measuring the corresponding relationship between the temperature and time of the test motor under a plurality of second preset currents;

[0029] The corresponding relationship between the temperature and time of the motor under the input current is determined according to the corresponding relationship between the temperature and time under the plurality of second preset currents.

[0030] According to another aspect of the present invention, there is provided a temperature estimation device for a motor, comprising:

[0031] An acquisition module, used to acquire a balance current threshold value corresponding to when the balance temperature of the motor reaches a preset limit temperature;

[0032] A first processing module, used for determining the relationship between the input current of the motor and the balancing current threshold, and obtaining a thermal capacity parameter of the motor under the input current;

[0033] a second processing module, configured to calculate the cumulative thermal capacity of the motor according to the thermal capacity parameter and a first preset formula if the current of the motor is greater than the balancing current threshold; and to calculate the cumulative thermal capacity of the motor according to the thermal capacity parameter and a second preset formula if the current of the motor is less than or equal to the balancing current threshold; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1;

[0034] An estimation module is used to estimate the temperature of the motor according to the accumulated heat capacity and a third preset formula.

[0035] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0036] one or more processors;

[0037] A storage device for storing one or more programs;

[0038] When the one or more programs are executed by the one or more processors, the one or more processors implement the temperature estimation method of the motor as described above.

[0039] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the temperature estimation method of the motor as described above when the instructions are executed.

[0040] The technical solution of the embodiment of the present invention adopts a method for estimating the temperature of a motor, including: obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature; judging the relationship between the input current of the motor and the balancing current threshold, and obtaining the thermal capacity parameter of the motor under the input current; if the current of the motor is greater than the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and the first preset formula; if the current of the motor is less than or equal to the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and the second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1; the temperature of the motor is estimated according to the cumulative thermal capacity and the third preset formula. The method for estimating the temperature of the motor of this embodiment does not require the use of a temperature sensor, but estimates based on the input current of the motor, thus having the advantage of low cost. The cumulative thermal capacity is calculated in different ways according to the relationship between the input current and the balancing current threshold, and the temperature of the motor is estimated using the cumulative thermal capacity, so that the correlation between the cumulative thermal capacity and the motor temperature is higher, and the temperature of the motor can be estimated more accurately.

[0041] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A flow chart of a method for estimating the temperature of a motor provided by an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the corresponding relationship between the temperature and time of a motor provided by an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the corresponding relationship between the temperature and time of another motor provided by an embodiment of the present invention;

[0046] Figure 4-Figure 9 A comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 25° C. and the input current is greater than the balancing current threshold;

[0047] Figure 10-Figure 15A comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 40° C. and the input current is greater than the balancing current threshold;

[0048] Figure 16-Figure 21 A comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 80° C. and the input current is greater than the balancing current threshold;

[0049] Figure 22-Figure 24 A comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the input current is less than the balancing current threshold;

[0050] Fig.25 A schematic diagram of the structure of a temperature estimation device for a motor provided by an embodiment of the present invention;

[0051] Fig.26 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0053] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0054] Figure 1 A flow chart of a method for estimating the temperature of a motor provided by an embodiment of the present invention, referring to Figure 1 The temperature estimation methods of the motor include:

[0055] Step S110, obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature;

[0056] Specifically, the motor is, for example, a permanent magnet synchronous motor in an automobile electric power steering system. The equilibrium temperature of the motor is the temperature at which the heat generation and heat dissipation of the motor reach a balance, and the motor is in a relatively stable operation stage. The preset limit temperature is the upper limit of the temperature at which the motor can operate normally. When the temperature of the motor exceeds the preset limit temperature, the probability of motor failure is high. The preset limit temperature can be determined according to the type of motor. For example, for a permanent magnet synchronous motor, its preset limit temperature is, for example, 155°C. The equilibrium temperature of the motor corresponding to different currents is different. When the motor is running at a certain current, when its equilibrium temperature reaches the preset limit temperature, the current is the equilibrium current threshold. It should be noted that in some embodiments, when the motor is running at a certain current, the equilibrium temperature is within a preset range from the preset limit temperature, that is, the current can be used as the equilibrium current threshold. The preset range is, for example, 1% of the preset limit temperature.

[0057] Step S120, determining the relationship between the input current of the motor and the balance current threshold, and obtaining the thermal capacity parameter of the motor under the input current;

[0058] Specifically, the thermal capacity parameters of the motor are used to calculate the cumulative thermal capacity of the motor. When the input current of the motor is different, the corresponding thermal capacity parameters are also different. When the input current of the motor is less than or equal to the balance current threshold, the temperature of the motor rises slowly; when the input current of the motor is greater than the balance current threshold, the temperature of the motor rises quickly.

[0059] If the input current of the motor is greater than the balancing current threshold, step S130 is executed; if the input current of the motor is less than or equal to the balancing current threshold, step S140 is executed;

[0060] Step S130, calculating the cumulative heat capacity of the motor according to the heat capacity parameter and the first preset formula; Step S140, calculating the cumulative heat capacity of the motor according to the heat capacity parameter and the second preset formula; wherein the cumulative heat capacity is greater than or equal to 0 and less than or equal to 1;

[0061] Specifically, the cumulative heat capacity of the motor is used to characterize the accumulation ratio of the heat capacity of the motor. In the initial state, the cumulative heat capacity of the motor is 0. When the motor reaches the preset limit temperature, the cumulative heat capacity of the motor is 100%. The first preset formula and the second preset formula have different required heat capacity parameters, and the specific heat capacity parameters will be described later.

[0062] Step S150, estimating the temperature of the motor according to the accumulated heat capacity and a third preset formula.

[0063] Specifically, the cumulative heat capacity is positively correlated with the temperature of the motor. The higher the cumulative heat capacity, the higher the temperature of the motor; the lower the cumulative heat capacity, the lower the temperature of the motor. Once the cumulative heat capacity is obtained, it can be used to estimate the temperature of the motor. From the above analysis, it can be seen that the temperature estimation method of the motor in this embodiment does not require the use of a temperature sensor, but is estimated based on the input current of the motor, so it has the advantage of low cost. The cumulative heat capacity is calculated in different ways according to the relationship between the input current and the balance current threshold, and the cumulative heat capacity is used to estimate the temperature of the motor, so that the correlation between the cumulative heat capacity and the motor temperature is higher, and the temperature of the motor can be estimated more accurately.

[0064] The technical solution of this embodiment adopts a method for estimating the temperature of the motor, including: obtaining the corresponding balancing current threshold when the balancing temperature of the motor reaches the preset limit temperature; judging the relationship between the input current of the motor and the balancing current threshold, and obtaining the thermal capacity parameter of the motor under the input current; if the current of the motor is greater than the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and the first preset formula; if the current of the motor is less than or equal to the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and the second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1; the temperature of the motor is estimated according to the cumulative thermal capacity and the third preset formula. The method for estimating the temperature of the motor of this embodiment does not require the use of a temperature sensor, but estimates it based on the input current of the motor, thus having the advantage of low cost. The cumulative thermal capacity is calculated in different ways according to the relationship between the input current and the balancing current threshold, and the temperature of the motor is estimated using the cumulative thermal capacity, so that the correlation between the cumulative thermal capacity and the motor temperature is higher, and the temperature of the motor can be estimated more accurately.

[0065] Optionally, obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature includes:

[0066] Read the motor's balancing current threshold.

[0067] Specifically, the temperature estimation method of the motor may be executed by a temperature estimation device of the motor, for example, and the estimation device may read a balancing current threshold value corresponding to the motor from a memory.

[0068] Optionally, obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature includes:

[0069] Inputting a first preset current into the test motor to determine a balanced temperature of the test motor;

[0070] The first preset current is adjusted until the balancing temperature of the test motor reaches the preset limit temperature; and the first preset current is used as the balancing current threshold.

[0071] Specifically, in this embodiment, the motor can be used as a test motor before the motor leaves the factory to obtain the balance current threshold of the motor. Alternatively, a motor of the same batch and model as the motor can be used as a test motor. By testing the test motor, the balance current threshold corresponding to the motor is determined. The specific test method is, for example, first determining an initial value of a first preset current, and the initial value range of the first preset current is, for example, 40% to 50% of the maximum current corresponding to the motor. At the initial value of the first preset current, the balance temperature of the motor is measured. If the balance temperature is equal to the preset limit temperature, or the difference with the preset limit temperature is within a preset range, the initial value of the first preset current is used as the balance current threshold. If the balance temperature of the motor is less than the preset limit temperature at the initial value of the first preset current, the value of the first preset current can be increased until the balance temperature of the motor reaches the preset limit temperature. If the balance temperature of the motor is greater than the preset limit temperature at the initial value of the first preset current, the value of the first preset current can be reduced until the balance temperature of the motor reaches the preset limit temperature.

[0072] Optionally, obtaining the thermal capacity parameter of the motor under the input current includes:

[0073] Obtain the corresponding relationship between the temperature and time of the motor under the input current, and determine the thermal capacity parameter according to the corresponding relationship between the temperature and time;

[0074] If the input current is greater than the balancing current threshold, the thermal capacity parameters include: the temperature rise time T from the initial temperature to the preset limit temperature trip , a first proportionality coefficient K, wherein the proportionality coefficient K is the difference between the preset limit temperature and the initial temperature; if the input current is less than or equal to the balancing current threshold, the thermal capacity parameters include: a second proportionality coefficient TCU END , time constant τ and first proportional coefficient K; wherein the second proportional coefficient TCU END It is the difference between the equilibrium temperature corresponding to the input current and the initial temperature, divided by the difference between the preset limit temperature and the initial temperature.

[0075] Specifically, the correspondence between the temperature of the motor under the input current and time indicates the relationship between the temperature of the motor and time under the current, which can be reflected by the temperature rise curve of the motor under the input current. The temperature of the motor starts to change from the initial temperature, and the initial temperature is, for example, 25°C or 40°C. The temperature of the motor includes, for example, the inner bottom temperature of the motor and the inner cover temperature of the motor. The inner bottom temperature of the motor and the inner cover temperature of the motor are close, and any one of them can be used as the temperature of the motor. For each input current of the motor, there is a corresponding temperature rise curve. That is to say, the correspondence between temperature and time is different under different input currents.

[0076] Optionally, obtaining the corresponding relationship between the temperature of the motor under the input current and the time includes:

[0077] The corresponding relationship between the temperature and time of the test motor under multiple second preset currents is measured.

[0078] More specifically, when determining the balance current threshold of the motor (in I rate After denoted by ), multiple second preset currents can be determined according to the balancing current threshold. For example, the second preset current is 0.25*I rate 、0.5*I rate 、0.75*I rate 、1.25*I rate 、1.5*I rate 、1.75*I rate or I max Etc. Among them, I max is the maximum current corresponding to the motor. The temperature rise curve of the motor is measured under the second preset current.

[0079] The corresponding relationship between the temperature and time of the motor under the input current is determined according to the corresponding relationship between the temperature and time under multiple second preset currents.

[0080] Specifically, if the input current takes a value within a plurality of second preset currents, the temperature rise curve corresponding to the second preset current can be directly retrieved as the corresponding relationship between the temperature and time corresponding to the input current. If the input current is not equal to any second preset current, the temperature rise curve of the motor under any current can be fitted based on the temperature rise curves corresponding to the plurality of second preset currents. It should be noted that the temperature rise curve corresponding to the current less than the balancing current threshold is fitted by the temperature rise curves corresponding to the plurality of second preset currents less than the balancing current threshold. The temperature rise curve corresponding to the current greater than the balancing current threshold is fitted by the temperature rise curves corresponding to the plurality of second preset currents greater than the balancing current threshold. The fitting method may be, for example, linear fitting or nonlinear fitting.

[0081] It should also be noted that the temperature rise curves corresponding to multiple second preset currents can be stored in the memory. When the input current is not equal to any second preset current, the temperature rise curve corresponding to the input current can be calculated in real time. Thus, the amount of data stored in the memory can be reduced.

[0082] like Figure 2 and Figure 3 As shown, Figure 2 A schematic diagram of the corresponding relationship between the temperature and time of a motor provided by an embodiment of the present invention, Figure 3 A schematic diagram of the corresponding relationship between the temperature and time of another motor provided by an embodiment of the present invention. Figure 2 The corresponding motor input current is greater than the balance current threshold, Figure 3The corresponding motor input current is less than the balance current threshold. Figure 2 As shown in the figure, after determining the corresponding relationship between the temperature and time of the motor under the input current, the temperature rise time T can be determined from the corresponding relationship. trip And the first proportionality coefficient. Among them, the temperature rise time T trip Equal to reaching the preset limit temperature T max The time required for the motor to reach the initial temperature minus the time corresponding to the motor's initial temperature. The first proportional coefficient K is the preset limit temperature minus the initial temperature. In other words, the first proportional coefficient K of the motor is the preset limit temperature T corresponding to the motor. max Subtract the initial temperature of the motor. The first preset formula is:

[0083]

[0084] Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δtth calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0085] like Figure 3 As shown in FIG. 1 , if the input current of the motor is less than the balance current threshold, the balance temperature T corresponding to the input current can be obtained from the temperature rise curve corresponding to the input current. temp , then the second proportionality coefficient Wherein, Temp(0) is the initial temperature of the motor. The time constant τ is used to correct the second preset formula, which can be determined according to the temperature rise curves corresponding to multiple second preset currents that are less than or equal to the balancing current threshold. When the input current of the motor is less than the balancing current threshold, the calculation formula for the cumulative thermal capacity is:

[0086] TCU(k·Δt)=TCU END ×(1-e -Δt / τ )+TCU((k-1)·Δt)×e -Δt / τ ;

[0087] Since Δt / τ<<1, then 1-e -Δt / τ ≈Δt / τ, after substituting into the above formula, the final second preset formula can be obtained, where the second preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δt-th calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0088] Optionally, in some embodiments, the temperature rise curve when the input current of the motor is equal to the balance current threshold can be measured, such as Figure 3As shown, when the temperature of the motor reaches the preset limit temperature, the input current of the motor is set to zero to obtain the natural cooling curve of the motor. According to the complete temperature rise and cooling curve of the motor, the time constant τ is obtained by curve fitting. In addition, the time constant τ can also be corrected according to the temperature rise curve and natural cooling curve corresponding to multiple second preset currents less than the balance current threshold.

[0089] Optionally, the third preset formula is: Temp(k·Δt)=TCU(k·Δt)×K+Temp(0);

[0090] Wherein, Temp(k·Δt) is the estimated temperature of the motor in the k·Δtth calculation cycle, and Temp(0) is the initial temperature of the motor. After the cumulative thermal capacity TCU(k·Δt) is obtained, the temperature of the motor can be estimated according to the third preset formula. Thus, the estimated temperature of the motor can be accurately obtained, so that the user can adjust the motor state according to the temperature of the motor in time.

[0091] Exemplarily, the effectiveness of the present invention is verified by system simulation, and the temperature estimation method of the motor of the present invention can be verified by a Simulink simulation model. Figure 4-Figure 9 This is a comparison chart of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 25°C and the input current is greater than the balancing current threshold. Figure 4 The corresponding input current is 30A. Figure 5 The corresponding input current is 35A. Figure 6 The corresponding input current is 40A. Figure 7 The corresponding input current is 45A. Figure 8 The corresponding input current is 50A. Fig. 9 The corresponding input current is 52A. Figure 4-Figure 9 It can be seen that when the ambient temperature is 25 degrees Celsius, the temperature estimation method of the present invention has a high degree of coincidence with the actual temperature of the motor. Figure 10-Figure 15 This is a comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 40° C. and the input current is greater than the balancing current threshold, wherein: Fig.10 The corresponding input current is 30A. Fig.11 The corresponding input current is 35A. Fig.12 The corresponding input current is 40A. Fig.13 The corresponding input current is 45A. Fig.14 The corresponding input current is 50A. Fig.15 The corresponding input current is 52A. Figure 10-Figure 15 It can be seen that when the ambient temperature is 40 degrees Celsius, the temperature estimation method of the present invention has a high degree of coincidence with the actual temperature of the motor. Figure 16-Figure 21This is a comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the ambient temperature is 80° C. and the input current is greater than the balancing current threshold, wherein: Fig.16 The corresponding input current is 25A. Fig.17 The corresponding input current is 30A. Fig.18 The corresponding input current is 35A. Fig.19 The corresponding input current is 40A. Fig. 20 The corresponding input current is 45A. Fig.21 The corresponding input current is 50A. Figure 16-Figure 21 It can be seen that when the ambient temperature is 80 degrees Celsius, the temperature estimation method of the present invention has a high degree of coincidence with the actual temperature of the motor. Figure 4-Figure 21 The corresponding input current is greater than the balancing current threshold. For the case where the input current is less than the balancing current threshold, such as Figure 22-Figure 24 As shown, Figure 22-Figure 24 This is a comparison diagram of the temperature estimated by the temperature estimation method provided by the embodiment of the present invention and the actual temperature of the motor when the input current is less than the balancing current threshold, wherein: Fig. 22 The corresponding ambient temperature is 25℃. Fig.23 The corresponding ambient temperature is 40℃. Fig.24 The corresponding ambient temperature is 80℃. Figure 22-Figure 24 It can be seen that when the input current is less than the balancing current threshold, the temperature estimation method of the present invention has a high degree of coincidence with the actual temperature of the motor. From the above analysis, it can be seen that the temperature estimation method provided by the embodiment of the present invention has a high accuracy in estimating the temperature of the motor.

[0092] The present invention also provides a temperature estimation device for a motor, such as Fig.25 As shown, Fig.25 A schematic diagram of the structure of a temperature estimation device for a motor provided by an embodiment of the present invention. The temperature estimation device for the motor includes: an acquisition module 310, a first processing module 320, a second processing module 330 and an estimation module 340. The acquisition module 310 is used to obtain the corresponding balance current threshold when the balance temperature of the motor reaches the preset limit temperature; the first processing module 320 is used to determine the relationship between the input current of the motor and the balance current threshold, and obtain the thermal capacity parameter of the motor under the input current; the second processing module 330 is used to calculate the cumulative thermal capacity of the motor according to the thermal capacity parameter and the first preset formula if the current of the motor is greater than the balance current threshold; if the current of the motor is less than or equal to the balance current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and the second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1; the estimation module 340 is used to estimate the temperature of the motor according to the cumulative thermal capacity and the third preset formula. The specific working principle of the temperature estimation device for the motor can refer to the description of the temperature estimation method of the motor in the present invention, which will not be repeated here.

[0093] Optionally, the acquisition module 310 is used to read the balance current threshold of the motor;

[0094] and / or, for inputting a first preset current into a test motor to determine a balance temperature of the test motor;

[0095] The first preset current is adjusted until the balancing temperature of the test motor reaches the preset limit temperature; and the first preset current is used as the balancing current threshold.

[0096] Optionally, the first processing module 320 is used to obtain the corresponding relationship between the temperature and time of the motor under the input current, and determine the heat capacity parameter according to the corresponding relationship between the temperature and time;

[0097] If the input current is greater than the balancing current threshold, the thermal capacity parameters include: the temperature rise time T from the initial temperature to the preset limit temperature tr i p , a first proportionality coefficient K, wherein the proportionality coefficient K is the difference between the preset limit temperature and the initial temperature;

[0098] If the input current is less than or equal to the balancing current threshold, the thermal capacitance parameters include: the second proportional coefficient TCU END , time constant τ and first proportional coefficient K; wherein the second proportional coefficient TCU END It is the difference between the equilibrium temperature corresponding to the input current and the initial temperature, divided by the difference between the preset limit temperature and the initial temperature.

[0099] Optionally, the first preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δtth calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0100] Optionally, the second preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δtth calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

[0101] Optionally, the third preset formula is: Temp(k·Δt)=TCU(k·Δt)×K+Temp(0); wherein Temp(k·Δt) is the estimated temperature of the motor in the k·Δtth calculation cycle, and Temp(0) is the initial temperature of the motor.

[0102] Optionally, the first processing module is used to measure the correspondence between the temperature and time of the test motor under multiple second preset currents; and determine the correspondence between the temperature and time of the motor under the input current based on the correspondence between the temperature and time under multiple second preset currents.

[0103] The present invention also provides an electronic device, such as Fig.26 As shown, Fig.26 The electronic device includes a processor 70, a memory 71, an input device 72, and an output device 73; the number of processors 70 in the electronic device can be one or more. Fig.26 A processor 70 is taken as an example; the processor 70, the memory 71, the input device 72 and the output device 73 in the electronic device can be connected by a bus or other means. Fig.26 The example of connecting through bus is taken in the following.

[0104] The memory 71, as a computer-readable storage medium, can be used to store software programs, computer executable programs and modules, such as program instructions / modules corresponding to the temperature estimation method of the motor in the embodiment of the present invention (for example, the acquisition module 310, the first processing module 320, the second processing module 330 and the estimation module 340 in the temperature estimation device of the motor). The processor 70 executes various functional applications and data processing of the electronic device by running the software programs, instructions and modules stored in the memory 71, that is, realizes the temperature estimation method of the motor described above.

[0105] The memory 71 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system and at least one application required for a function; the data storage area may store data created according to the use of the terminal, etc. In addition, the memory 71 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some instances, the memory 71 may further include a memory remotely arranged relative to the processor 70, and these remote memories may be connected to the device / terminal / server via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0106] The input device 72 may be used to receive input digital or character information and generate key signal input related to user settings and function control of the electronic device. The output device 73 may include a display device such as a display screen.

[0107] The present invention further provides a computer-readable storage medium, wherein the computer-executable instructions are used in the temperature estimation method of the motor provided by any embodiment of the present invention when executed by a computer processor.

[0108] Of course, the storage medium containing computer executable instructions provided in an embodiment of the present invention is not limited to the method operations described above, and can also execute related operations in the temperature estimation method of the motor provided in any embodiment of the present invention.

[0109] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0110] It is worth noting that in the embodiment of the above-mentioned search device, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0111] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0112] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for estimating the temperature of a motor, characterized in that: include: Obtaining a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature; Determining the relationship between the input current of the motor and the balancing current threshold, and obtaining the thermal capacity parameter of the motor under the input current; If the current of the motor is greater than the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and a first preset formula; If the current of the motor is less than or equal to the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and a second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1; The temperature of the motor is estimated according to the accumulated heat capacity and a third preset formula.

2. The method for estimating the temperature of a motor according to claim 1, characterized in that: The step of obtaining a corresponding balancing current threshold when the balancing temperature of the motor reaches a preset limit temperature includes: Reading a balancing current threshold of the motor; And / or, the obtaining of a balancing current threshold corresponding to when the balancing temperature of the motor reaches a preset limit temperature includes: Inputting a first preset current into a test motor to determine a balance temperature of the test motor; The first preset current is adjusted until the equilibrium temperature of the test motor reaches the preset limit temperature; and the first preset current is used as the equilibrium current threshold.

3. The method for estimating the temperature of a motor according to claim 1, characterized in that: The obtaining of the thermal capacity parameter of the motor under the input current comprises: Obtaining a corresponding relationship between the temperature and time of the motor under the input current, and determining the heat capacity parameter according to the corresponding relationship between the temperature and time; If the input current is greater than the balancing current threshold, the thermal capacity parameters include: the temperature rise time T from the initial temperature to the preset limit temperature trip , a first proportionality coefficient K, wherein the proportionality coefficient K is the difference between the preset limit temperature and the initial temperature; If the input current is less than or equal to the balancing current threshold, the thermal capacity parameter includes: a second proportional coefficient TCU END , time constant τ and the first proportional coefficient K; wherein the second proportional coefficient TCU END The difference between the equilibrium temperature corresponding to the input current and the initial temperature is divided by the difference between the preset limit temperature and the initial temperature.

4. The method for estimating the temperature of a motor according to claim 3, characterized in that: The first preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δt-th calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

5. The method for estimating the temperature of a motor according to claim 3, characterized in that: The second preset formula is: Wherein, TCU(k·Δt) is the cumulative heat capacity of the k·Δt-th calculation cycle; k is greater than or equal to 1, TCU(0·Δt)=0, and Δt is the time of the calculation cycle.

6. The method for estimating the temperature of a motor according to claim 4 or 5, characterized in that: The third preset formula is: Temp(k·Δt)=TCU(k·Δt)×K+Temp(0); Wherein, Temp(k·Δt) is the estimated temperature of the motor in the k·Δt-th calculation cycle, and Temp(0) is the initial temperature of the motor.

7. The method for estimating the temperature of a motor according to claim 3, characterized in that: The obtaining of the corresponding relationship between the temperature of the motor under the input current and the time includes: Measuring the corresponding relationship between the temperature and time of the test motor under a plurality of second preset currents; The corresponding relationship between the temperature and time of the motor under the input current is determined according to the corresponding relationship between the temperature and time under the plurality of second preset currents.

8. A temperature estimation device for a motor, characterized in that: include: An acquisition module, used to acquire a balance current threshold value corresponding to when the balance temperature of the motor reaches a preset limit temperature; A first processing module, used for determining the relationship between the input current of the motor and the balancing current threshold, and obtaining a thermal capacity parameter of the motor under the input current; a second processing module, configured to calculate the cumulative thermal capacity of the motor according to the thermal capacity parameter and a first preset formula if the current of the motor is greater than the balancing current threshold; If the current of the motor is less than or equal to the balancing current threshold, the cumulative thermal capacity of the motor is calculated according to the thermal capacity parameter and a second preset formula; wherein the cumulative thermal capacity is greater than or equal to 0 and less than or equal to 1; An estimation module is used to estimate the temperature of the motor according to the accumulated heat capacity and a third preset formula.

9. An electronic device, characterized in that: The electronic device comprises: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the temperature estimation method of the motor as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the temperature estimation method of the motor as claimed in any one of claims 1 to 7 when executed.

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