Method and device for determining motor torque

Abstract

The present disclosure relates to a method and apparatus for determining motor torque, and relates to the field of vehicle control. The method comprises: determining a first torque based on the input current and the number of magnetic pole pairs of the motor, determining a second torque based on the output power and speed of the motor, determining a first torque difference based on the first torque and the current target torque of the motor, determining a second torque difference based on the second torque and the target torque, determining a comprehensive torque difference based on the first torque difference and the second torque difference, and determining the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference. The present disclosure obtains a comprehensive torque difference based on the first torque difference and the second torque difference, and further obtains the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference, thereby improving the accuracy of determining the output torque of the motor.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle control, and in particular, to a method and device for determining motor torque. Background Art

[0002] With the rapid development of society, the number of cars on the road continues to increase. As one of the core components of a car, the performance of the electric drive system has a significant impact on its safety, economy, and environmental performance. The electric drive system consists of a motor and its controller. Accurately determining the motor's output torque is key to the system's precise control of the motor. Currently, the motor's output torque is typically calculated based on the motor's input current and number of magnetic pole pairs, or based on the motor's output power and speed. Both methods require high accuracy of the relevant parameters. However, due to factors such as sensor precision, cost, and space requirements, the accuracy of the relevant parameters is difficult to meet, resulting in low output torque accuracy. Summary of the Invention

[0003] The present invention aims to provide a method and apparatus for determining motor torque, so as to improve the accuracy of determining the output torque of the motor.

[0004] According to a first aspect of an embodiment of the present disclosure, a method for determining motor torque is provided, the method comprising:

[0005] Determine the first torque according to the input current and the number of magnetic pole pairs of the motor, and determine the second torque according to the output power and the speed of the motor;

[0006] determining a first torque difference according to the first torque and a current target torque of the motor, and determining a second torque difference according to the second torque and the target torque;

[0007] determining a comprehensive torque difference based on the first torque difference and the second torque difference;

[0008] An output torque of the motor is determined according to the first torque, the second torque, and the comprehensive torque difference.

[0009] Optionally, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the speed of the motor, the method further includes:

[0010] The input current, the rotational speed, and the target torque are obtained.

[0011] Optionally, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, the method further includes:

[0012] Determining motor parameters according to the input current, the motor parameters including flux linkage and inductance;

[0013] The determining of the first torque according to the input current and the number of magnetic pole pairs of the motor includes:

[0014] The first torque is determined according to the input current, the number of magnetic pole pairs, and the motor parameters.

[0015] Optionally, before determining the second torque according to the output power and the rotational speed of the motor, the method further includes:

[0016] determining an input voltage of the motor according to the input current;

[0017] The output power is determined according to the input voltage and the input current.

[0018] Optionally, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the speed of the motor, the method further includes:

[0019] Sampling a calibrated torque range of the motor to obtain a first number of sample target torques, and sampling a calibrated speed range of the motor to obtain a second number of sample speeds;

[0020] combining the first number of sample target torques and the second number of sample speeds to obtain a third number of groups of input parameters, where the third number is the product of the first number and the second number, and each group of input parameters includes one sample target torque and one sample speed;

[0021] For each set of input parameters, determining a first sample torque corresponding to the set of input parameters based on the control current corresponding to the sample target torque included in the set of input parameters and the number of magnetic pole pairs, and determining a second sample torque corresponding to the set of input parameters based on a sample output power and the sample speed included in the set of input parameters, wherein the sample output power is determined based on the control current;

[0022] Determining a first sample torque difference and a second sample torque difference corresponding to the set of input parameters based on the sample target torque included in the set of input parameters and the first sample torque and the second sample torque corresponding to the set of input parameters;

[0023] Determining a comprehensive sample torque difference corresponding to the set of input parameters based on the first sample torque difference and the second sample torque difference corresponding to the set of input parameters according to the first initial corresponding relationship;

[0024] The third number group of input parameters and the comprehensive sample torque difference corresponding to each group of input parameters are fitted to obtain a first corresponding relationship, which is used to determine the comprehensive torque difference according to the first torque difference and the second torque difference.

[0025] Optionally, after fitting the integrated sample torque difference corresponding to each group of input parameters using the third number of groups to obtain the first corresponding relationship, the method further includes:

[0026] For each set of input parameters, according to the second initial corresponding relationship, the output sample torque corresponding to the set of input parameters is determined based on the first sample torque, the second sample torque, and the comprehensive sample torque difference;

[0027] The input parameters of the third group are fitted with the output sample torque corresponding to each group of the input parameters to obtain a second corresponding relationship, which is used to determine the output torque based on the first torque, the second torque and the comprehensive torque difference.

[0028] According to a second aspect of an embodiment of the present disclosure, a device for determining motor torque is provided, the device comprising:

[0029] a torque determination module, configured to determine a first torque according to an input current and a number of magnetic pole pairs of the motor, and to determine a second torque according to an output power and a rotational speed of the motor;

[0030] a torque difference determining module, configured to determine a first torque difference according to the first torque and a current target torque of the motor, and to determine a second torque difference according to the second torque and the target torque;

[0031] a first processing module, configured to determine a comprehensive torque difference based on the first torque difference and the second torque difference;

[0032] A second processing module is configured to determine an output torque of the motor according to the first torque, the second torque and the comprehensive torque difference.

[0033] Optionally, the device further comprises:

[0034] An acquisition module is used to acquire the input current, the rotational speed and the target torque before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the rotational speed of the motor.

[0035] Optionally, the torque determination module is configured to:

[0036] Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, motor parameters are determined according to the input current, and the motor parameters include magnetic flux and inductance; the first torque is determined according to the input current, the number of magnetic pole pairs and the motor parameters.

[0037] Optionally, the torque determination module is configured to:

[0038] Before determining the second torque according to the output power and the rotational speed of the motor, the input voltage of the motor is determined according to the input current; and the output power is determined according to the input voltage and the input current.

[0039] Optionally, the device further comprises:

[0040] a sampling module, configured to sample a calibrated torque range of the motor to obtain a first number of sample target torques, and sample a calibrated speed range of the motor to obtain a second number of sample speeds, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the speed of the motor;

[0041] a combining module, configured to combine the first number of sample target torques with the second number of sample speeds to obtain a third number of groups of input parameters, where the third number is the product of the first number and the second number, and each group of input parameters includes one sample target torque and one sample speed;

[0042] The torque determination module is further configured to determine, for each set of input parameters, a first sample torque corresponding to the set of input parameters based on the control current corresponding to the sample target torque included in the set of input parameters and the number of magnetic pole pairs, and to determine a second sample torque corresponding to the set of input parameters based on a sample output power and the sample speed included in the set of input parameters, wherein the sample output power is determined based on the control current;

[0043] The torque difference determination module is further configured to determine a first sample torque difference and a second sample torque difference corresponding to the set of input parameters based on the sample target torque included in the set of input parameters and the first sample torque and the second sample torque corresponding to the set of input parameters;

[0044] The first processing module is further configured to determine, according to the first initial corresponding relationship, a comprehensive sample torque difference corresponding to the set of input parameters based on the first sample torque difference and the second sample torque difference corresponding to the set of input parameters;

[0045] The first fitting module is used to fit the input parameters of the third group and the comprehensive sample torque difference corresponding to each group of the input parameters to obtain a first corresponding relationship, and the first corresponding relationship is used to determine the comprehensive torque difference based on the first torque difference and the second torque difference.

[0046] Optionally, the second processing module is further configured to, after fitting the third number of groups of input parameters and the comprehensive sample torque difference corresponding to each group of input parameters to obtain the first corresponding relationship, determine, for each group of input parameters, the output sample torque corresponding to the group of input parameters according to the first sample torque, the second sample torque, and the comprehensive sample torque difference according to the second initial corresponding relationship;

[0047] The device further comprises:

[0048] The second fitting module is used to fit the input parameters of the third group and the output sample torque corresponding to each group of the input parameters to obtain a second corresponding relationship, and the second corresponding relationship is used to determine the output torque based on the first torque, the second torque and the comprehensive torque difference.

[0049] Through the above technical solution, the present disclosure first determines a first torque based on the input current and the number of magnetic pole pairs of the motor, and determines a second torque based on the output power and speed of the motor. Then, a first torque difference is determined based on the first torque and the current target torque of the motor, and a second torque difference is determined based on the second torque and the target torque. Then, a comprehensive torque difference is determined based on the first torque difference and the second torque difference. Finally, the output torque of the motor is determined based on the first torque, the second torque, and the comprehensive torque difference. The present disclosure obtains a comprehensive torque difference based on the first torque difference and the second torque difference, and further obtains the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference, thereby improving the accuracy of determining the output torque of the motor.

[0050] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0052] Figure 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0053] Figure 2 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0054] Figure 3 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0055] Figure 4 is based on Figure 3 The embodiment shows a schematic diagram of the relationship between inductance and current;

[0056] Figure 5 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0057] Figure 6 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0058] Figure 7 is a flow chart showing a method for determining motor torque according to an exemplary embodiment;

[0059] Figure 8 is a block diagram of a device for determining motor torque according to an exemplary embodiment;

[0060] Figure 9 is a block diagram of a device for determining motor torque according to an exemplary embodiment;

[0061] Figure 10 is a block diagram of a device for determining motor torque according to an exemplary embodiment;

[0062] Figure 11 The figure is a block diagram of a device for determining motor torque according to an exemplary embodiment. DETAILED DESCRIPTION

[0063] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0064] Figure 1 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 1 As shown, the method includes:

[0065] Step 101 : determining a first torque according to an input current and a number of magnetic pole pairs of a motor, and determining a second torque according to an output power and a rotational speed of the motor.

[0066] For example, the application scenario of the present disclosure can be a motor, which can be a DC motor, an asynchronous motor, a permanent magnet synchronous motor, etc., and the present disclosure does not make specific limitations on this. First, the input current of the motor can be sampled, and the sampled input current is transformed into the d-axis current and the q-axis current through the coordinate transformation relationship. Among them, the input current of the motor can be a three-phase current, and the d-axis can be understood as the axis where the magnetic pole of the rotor is located, and the direction is from the S pole to the N pole. The q-axis is perpendicular to the d-axis and the direction is rotated 90 degrees counterclockwise along the d-axis.

[0067] The motor's d-axis inductance, q-axis inductance, and flux linkage can then be derived from the d-axis and q-axis currents. Substituting the d-axis current, q-axis current, d-axis inductance, q-axis inductance, flux linkage, and magnetic pole pair number into Formula 1 yields the first torque. The magnetic pole pair number is the number of north and south pole pairs generated by the motor's stator winding when AC power is applied.

[0068] TqEst1=1.5*P n *(ψ*I q +(L d -L q )*I d *I q ) (Formula 1)

[0069] Among them, TqEst1 is the first torque, P n is the number of magnetic poles, ψ is the magnetic flux, L d is the d-axis inductance, L q is the q-axis inductance.

[0070] Furthermore, the output power and speed of the motor can be substituted into Formula 2 to obtain the second torque.

[0071]

[0072] Among them, TqEst2 is the second torque, P out is the output power and n is the speed.

[0073] Step 102 : determining a first torque difference according to the first torque and the current target torque of the motor, and determining a second torque difference according to the second torque and the target torque.

[0074] For example, after determining the first torque, the first torque and the current target torque of the motor can be substituted into Formula 3 to obtain a first torque difference. The target torque can be understood as the torque included in the torque command sent by the motor controller to the motor, that is, the torque expected to be output by the motor.

[0075] ΔTqEst1=TqCmd-TqEst1 (Formula 3)

[0076] Wherein, TqEst1 is the first torque, TqCmd is the target torque, and ΔTqEst1 is the first torque difference.

[0077] Furthermore, after determining the second torque, the second torque and the current target torque of the motor may be substituted into Formula 4 to obtain a second torque difference.

[0078] ΔTqEst2=TqCmd-TqEst2 (Formula 4)

[0079] Wherein, TqEst2 is the second torque, and ΔTqEst2 is the second torque difference.

[0080] Step 103: Determine a comprehensive torque difference based on the first torque difference and the second torque difference.

[0081] For example, after the first torque difference and the second torque difference are determined, the comprehensive torque difference may be determined according to a preset first correspondence relationship among the first torque difference, the second torque difference, and the comprehensive torque difference.

[0082] Specifically, the first corresponding relationship can be a first mapping table pre-established between the first torque difference, the second torque difference and the comprehensive torque difference. After determining the first torque difference and the second torque difference, the corresponding comprehensive torque difference can be found in the first mapping table. The first corresponding relationship can also be a first relationship function pre-fitted through experiments between the first torque difference, the second torque difference and the comprehensive torque difference. After determining the first torque difference and the second torque difference, the comprehensive torque difference can be obtained based on the first relationship function. The first corresponding relationship can also be a pre-trained first relationship model. The first torque difference and the second torque difference can be input into the first relationship model to obtain the comprehensive torque difference output by the first relationship model. The present disclosure does not make specific restrictions on this. Among them, the first relationship function can be, for example, as shown in Formula 5.

[0083] ΔTqEst=C1*ΔTqEst1+C2*ΔTqEst2 (Formula 5)

[0084] Among them, ΔTqEst is the comprehensive torque difference, and C1 and C2 are preset coefficients.

[0085] Step 104 : determining the output torque of the motor according to the first torque, the second torque and the comprehensive torque difference.

[0086] For example, after the comprehensive torque difference is determined, the output torque of the motor can be determined based on a preset second correspondence between the first torque, the second torque, the comprehensive torque difference and the output torque of the motor.

[0087] Specifically, the second corresponding relationship can be a second mapping table pre-established between the first torque, the second torque, the comprehensive torque difference and the output torque. After determining the first torque, the second torque and the comprehensive torque difference, the corresponding output torque can be found in the second mapping table. The second corresponding relationship can also be a second relationship function pre-fitted through experiments between the first torque, the second torque, the comprehensive torque difference and the output torque. After determining the first torque, the second torque and the comprehensive torque difference, the output torque can be obtained according to the second relationship function. The second corresponding relationship can also be a pre-trained second relationship model. The first torque, the second torque and the comprehensive torque difference can be input into the second relationship model to obtain the output torque output by the second relationship model. The present disclosure does not make specific restrictions on this. Among them, the second relationship function can be, for example, as shown in Formula 6.

[0088] TqEst=C 11 *TqEst1+C 22 *TqEst2+C 12 *TqEst1*TqEst2+C 21 *ΔTqEst+C 00 (Formula 6)

[0089] Among them, TqEst is the output torque, ΔTqEst is the comprehensive torque difference, C 11 、C 22 、C 12 、C 21 and C 00 It is a preset coefficient, which can be a constant or a variable related to the speed.

[0090] Furthermore, after obtaining the output torque of the motor, the target torque and the output torque can be subtracted to obtain the difference between the target torque and the output torque, and the output torque of the motor can be adjusted according to the difference. For example, when the target torque is greater than the output torque, the output torque can be increased. When the target torque of the motor is less than the output torque, the output torque can be reduced, so that the output torque of the motor is ultimately equal to the target torque.

[0091] In summary, the present disclosure first determines a first torque based on the input current and pole pair number of the motor, and determines a second torque based on the output power and speed of the motor. It then determines a first torque difference based on the first torque and the current target torque of the motor, and determines a second torque difference based on the second torque and the target torque. It then determines a comprehensive torque difference based on the first torque difference and the second torque difference. Finally, it determines the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference. The present disclosure obtains a comprehensive torque difference based on the first torque difference and the second torque difference, and further obtains the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference, thereby improving the accuracy of determining the output torque of the motor.

[0092] Figure 2 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 2 As shown, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the speed of the motor, the method further includes:

[0093] Step 105: Obtain input current, speed, and target torque.

[0094] For example, before determining the first torque and the second torque, the input current of the motor (such as three-phase current) can be obtained through a current sensor, the speed of the motor can be obtained through a speed sensor, and the target torque can be obtained by analyzing the torque instruction sent to the motor by the motor controller.

[0095] Figure 3 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 3 As shown, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, the method further includes:

[0096] Step 106 : Determine motor parameters according to the input current. The motor parameters include flux linkage and inductance.

[0097] Accordingly, one implementation of step 101 may be:

[0098] The first torque is determined according to the input current, the number of magnetic pole pairs and motor parameters.

[0099] For example, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, the motor parameters may be determined according to the relationship between the motor parameters and the input current, wherein the motor parameters include magnetic flux and inductance.

[0100] Specifically, a third mapping table of inductance and current can be established in advance, so that the inductance can be obtained by looking up the table, or a third relationship function between inductance and current can be fitted in advance through experiments, and the inductance can be obtained according to the third relationship function. Figure 4 The relationship between magnetic flux and current can be expressed as formula 7:

[0101]

[0102] Among them, ψ d is the d-axis magnetic flux, ψ q is the q-axis magnetic flux, L d is the d-axis inductance, L q is the q-axis inductance, ψ f is the flux linkage of the permanent magnets in the motor.

[0103] Furthermore, the input current, the number of magnetic pole pairs, the inductance, and the flux linkage can be substituted into Formula 1 to determine the first torque.

[0104] Figure 5 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 5 As shown, before determining the second torque according to the output power and the speed of the motor, the method further includes:

[0105] Step 107: Determine the input voltage of the motor according to the input current.

[0106] Step 108: Determine the output power according to the input voltage and the input current.

[0107] For example, before determining the second torque according to the output power and speed of the motor, the input current may be substituted into the voltage equation to obtain the input voltage of the motor. The voltage equation may be shown as Formula 8.

[0108]

[0109] Among them, U d is the d-axis voltage, U q is the q-axis voltage, R s is the resistance of the armature winding.

[0110] Furthermore, the input voltage and input current can be substituted into Formula 9 to obtain the output power.

[0111] P out =1.5*(U d *I d +U q *I q ) (Formula 9)

[0112] Figure 6 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 6 As shown, before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the speed of the motor, the method further includes:

[0113] Step 109 : sampling the calibrated torque range of the motor to obtain a first number of sample target torques, and sampling the calibrated speed range of the motor to obtain a second number of sample speeds.

[0114] For example, a preset first sampling function may be used to perform sampling within the calibrated torque range of the motor to obtain a first number of sample target torques. Alternatively, the calibrated torque range may be divided into a first number of segments, and the maximum target torque, minimum target torque, or average target torque in each segment may be used as the sample target torque. Furthermore, a preset second sampling function may be used to perform sampling within the calibrated speed range of the motor to obtain a second number of sample speeds. Alternatively, the calibrated speed range may be divided into a second number of segments, and the maximum speed, minimum speed, or average speed in each segment may be used as the sample speed.

[0115] The first sampling function and the second sampling function may be the same or different, and the method for sampling the calibrated torque range and the method for sampling the calibrated speed range may be the same or different.

[0116] Specifically, taking the calibrated torque range of 0-200Nm and the calibrated speed range of 0-10000r / min as an example, the calibrated torque range can be divided into 10 segments (that is, the first number is 10), and the minimum value of each segment can be taken as the sample target torque, that is, the sample target torque includes 0, 20, 40, 60, 80, 100, 120, 140, 160, 180, or the maximum value of each segment can be taken as the sample target torque, that is, the sample target torque includes 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, or the middle value of each segment can be taken as the sample target torque, that is, the sample target torque includes 10, 30, 50, 70, 90, 110, 130, 150, 170, 190. Furthermore, the calibrated speed range can be divided into 5 segments (i.e., the second number is 5), and the minimum value of each segment can be taken as the sample speed, i.e., the sample speeds include 0, 2000, 4000, 6000, and 8000. The maximum value of each segment can be taken as the sample speed, i.e., the sample speeds include 2000, 4000, 6000, 8000, and 10000. The middle value of each segment can also be taken as the sample speed, i.e., the sample speeds include 1000, 3000, 5000, 7000, and 9000.

[0117] Step 110 : Combine the first number of sample target torques and the second number of sample speeds to obtain a third number of groups of input parameters, where the third number is the product of the first number and the second number, and each group of input parameters includes a sample target torque and a sample speed.

[0118] For example, the first quantity is represented by N, the second quantity is represented by M, and N sample target torques and M sample speeds are combined to obtain M×N groups of input parameters, that is, the third quantity is M×N, and each group of input parameters includes a sample target torque and a sample speed.

[0119] Specifically, the first target torque sample can be denoted as TqCmd1, the second target torque sample as TqCmd2, and so on, with the Nth target torque sample as TqCmdN. Similarly, the first speed sample can be denoted as MotSpd1, the second speed sample as MotSpd2, and so on, with the Mth speed sample as MotSpdM. Thus, the M×N sets of input parameters can be shown in Table 1.

[0120] (MotSpd1, TqCmd1) (MotSpd1, TqCmd2) … (MotSpd1, TqCmdN) (MotSpd2, TqCmd1) (MotSpd2, TqCmd2) … (MotSpd2, TqCmdN) … … … … (MotSpdM, TqCmd1) (MotSpdM, TqCmd2) … (MotSpdM, TqCmdN)

[0121] Table 1

[0122] Step 111, for each set of input parameters, determine the first sample torque corresponding to the set of input parameters based on the control current corresponding to the sample target torque included in the set of input parameters and the number of magnetic poles, and determine the second sample torque corresponding to the set of input parameters based on the sample output power and the sample speed included in the set of input parameters, where the sample output power is determined based on the control current.

[0123] For example, for each set of input parameters, the control current corresponding to the sample target torque included in the set of input parameters can be transformed into a d-axis sample current and a q-axis sample current through coordinate transformation. The control current can be the target current corresponding to the target torque or the input current detected by the current sensor. The d-axis sample current and the q-axis sample current can then be used to obtain the motor's d-axis sample inductance, q-axis sample inductance, and sample flux linkage. Substituting the d-axis sample current, q-axis sample current, d-axis sample inductance, q-axis sample inductance, and pole pair number into Equation 10, the first sample torque corresponding to the set of input parameters can be obtained.

[0124] TqEst1'=1.5*P n *(ψ'*I' q +(L' d -L' q )*I' d *I' q ) (Formula 10)

[0125] Among them, TqEst1' is the first sample torque, P n is the number of magnetic pole pairs, I' q is the q-axis sample current corresponding to the control current, I' d is the d-axis sample current corresponding to the control current, ψ' is the sample magnetic flux, L'd is the d-axis sample inductance, L' q It should be noted that Formula 10 corresponds to Formula 1, that is, the method for calculating the first sample torque is the same as the method for calculating the first torque.

[0126] Furthermore, the d-axis sample current and q-axis sample current can be substituted into Formula 11 to obtain the corresponding d-axis sample voltage and q-axis sample voltage. The d-axis sample current, q-axis sample current, d-axis sample voltage, and q-axis sample voltage can then be substituted into Formula 12 to obtain the sample output power. The sample output power and the sample speed included in the set of input parameters can then be substituted into Formula 13 to obtain the second sample torque corresponding to the input parameters.

[0127]

[0128] P' out =1.5*(U' d *I' d +U' q *I' q ) (Formula 12)

[0129]

[0130] Among them, U' d is the d-axis sample voltage, U' q is the q-axis sample voltage, ψ' d is the d-axis sample magnetic flux ψ' q is the q-axis sample flux, n' is the sample speed, P' out is the sample output power, and TqEst2' is the second sample torque. It should be noted that Formula 13 corresponds to Formula 2, that is, the method for calculating the second sample torque is the same as the method for calculating the second torque.

[0131] Step 112 : determining a first sample torque difference and a second sample torque difference corresponding to the set of input parameters based on the sample target torque included in the set of input parameters and the first sample torque and the second sample torque corresponding to the set of input parameters.

[0132] Step 113 : Determine the comprehensive sample torque difference corresponding to the set of input parameters according to the first sample torque difference and the second sample torque difference corresponding to the set of input parameters in accordance with the first initial corresponding relationship.

[0133] For example, the sample target torque included in the set of input parameters and the first sample torque corresponding to the set of input parameters can be substituted into Formula 14 to obtain a first sample torque difference, and the sample target torque included in the set of input parameters and the second sample torque corresponding to the set of input parameters can be substituted into Formula 15 to obtain a second sample torque difference. The first sample torque difference and the second sample torque difference can both be the third quantity.

[0134] ΔTqEst1'=TqCmd'-TqEst1' (Formula 14)

[0135] ΔTqEst2'=TqCmd'-TqEst2' (Formula 15)

[0136] Wherein, ΔTqEst1 ′ is the first sample torque difference, TqCmd′ is the sample target torque, and ΔTqEst2 ′ is the second sample torque difference.

[0137] Furthermore, a first initial corresponding relationship may be determined according to motor characteristics. The first initial corresponding relationship may be, for example, as shown in Formula 16.

[0138] ΔTqEst'=A*ΔTqEst1'+B*ΔTqEst2' (Formula 16)

[0139] Wherein, ΔTqEst′ is the comprehensive sample torque difference, A is the first proportional coefficient corresponding to the first sample torque difference, and B is the second proportional coefficient corresponding to the second sample torque difference.

[0140] The first sample torque difference and the second sample torque difference corresponding to each set of input parameters can then be substituted into Formula 16 and combined according to the first initial correspondence to obtain the comprehensive sample torque difference corresponding to the set of input parameters, where the number of comprehensive sample torque differences can be the third number.

[0141] Step 114 , using the third number of groups of input parameters, fit the comprehensive sample torque difference corresponding to each group of input parameters to obtain a first corresponding relationship, which is used to determine the comprehensive torque difference based on the first torque difference and the second torque difference.

[0142] For example, a third number of first sample torque differences and a third number of second sample torque differences can be obtained based on a third number of groups of input parameters. A fitting operation is performed using the first sample torque differences and second sample torque differences corresponding to each group of input parameters as inputs and the comprehensive sample torque differences corresponding to each group of input parameters as outputs, thereby obtaining a first corresponding relationship between the comprehensive torque difference and the first torque difference and the second torque difference. The first corresponding relationship can, for example, be a first mapping table between the first torque difference, the second torque difference, and the comprehensive torque difference, or a first relationship function between the first torque difference, the second torque difference, and the comprehensive torque difference. The first corresponding relationship can be used in step 103 to determine the comprehensive torque difference based on the first torque difference and the second torque difference.

[0143] Figure 7 FIG. 1 is a flow chart showing a method for determining motor torque according to an exemplary embodiment. Figure 7 As shown, after fitting the third number group of input parameters and the comprehensive sample torque difference corresponding to each group of input parameters to obtain the first corresponding relationship, the method further includes:

[0144] Step 115 : For each set of input parameters, according to the second initial correspondence, the output sample torque corresponding to the set of input parameters is determined based on the first sample torque, the second sample torque, and the comprehensive sample torque difference corresponding to the set of input parameters.

[0145] Step 116 , using the third number of groups of input parameters, and fitting the output sample torque corresponding to each group of input parameters to obtain a second corresponding relationship, the second corresponding relationship is used to determine the output torque according to the first torque, the second torque and the comprehensive torque difference.

[0146] For example, after obtaining the first corresponding relationship, firstly, for each set of input parameters, a corresponding second initial corresponding relationship may be determined. The second initial corresponding relationship may be, for example, as shown in Formula 17.

[0147] TqEst'=C*TqEst1'+D*TqEst2'+ΔTqEst' (Formula 17)

[0148] Among them, TqEst' is the comprehensive sample torque difference, C is the third proportional coefficient corresponding to the first sample torque, and D is the fourth proportional coefficient corresponding to the second sample torque. C and D are determined based on the sample target torque included in each set of input parameters. C and D corresponding to each set of input parameters can be the same or different. In other words, the second initial correspondence corresponding to each set of input parameters can be the same or different.

[0149] Afterwards, according to the second initial correspondence relationship corresponding to each set of input parameters, the first sample torque, the second sample torque and the comprehensive sample torque difference corresponding to the set of input parameters can be substituted into Formula 17 to obtain the output sample torque corresponding to the set of input parameters.

[0150] Furthermore, a third number of first sample torques and a third number of second sample torques can be obtained based on a third number of groups of input parameters. A fitting operation is performed using the first sample torque, the second sample torque, and the combined sample torque difference corresponding to each group of input parameters as input, and the output sample torque difference corresponding to each group of input parameters as output, thereby obtaining a second corresponding relationship between the output torque and the first torque, the second torque, and the combined torque difference. The second corresponding relationship can, for example, be a second mapping table between the first torque, the second torque, the combined torque difference, and the output torque, or a second relationship function between the first torque, the second torque, the combined torque difference, and the output torque. The second corresponding relationship can be used in step 104 to determine the output torque based on the first torque, the second torque, and the combined torque difference. The second relationship function can, for example, be as shown in Equation 6.

[0151] In summary, the present disclosure first determines a first torque based on the input current and pole pair number of the motor, and determines a second torque based on the output power and speed of the motor. It then determines a first torque difference based on the first torque and the current target torque of the motor, and determines a second torque difference based on the second torque and the target torque. It then determines a comprehensive torque difference based on the first torque difference and the second torque difference. Finally, it determines the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference. The present disclosure obtains a comprehensive torque difference based on the first torque difference and the second torque difference, and further obtains the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference, thereby improving the accuracy of determining the output torque of the motor.

[0152] Figure 8 is a block diagram of a device for determining motor torque according to an exemplary embodiment. Figure 8 As shown, the device 200 includes:

[0153] The torque determination module 201 is configured to determine a first torque according to an input current and a number of magnetic pole pairs of the motor, and to determine a second torque according to an output power and a rotational speed of the motor.

[0154] The torque difference determination module 202 is configured to determine a first torque difference according to the first torque and a current target torque of the motor, and to determine a second torque difference according to the second torque and the target torque.

[0155] The first processing module 203 is configured to determine a comprehensive torque difference according to the first torque difference and the second torque difference.

[0156] The second processing module 204 is configured to determine the output torque of the motor according to the first torque, the second torque and the comprehensive torque difference.

[0157] Figure 9 is a block diagram of a device for determining motor torque according to an exemplary embodiment. Figure 9 As shown, the device 200 further includes:

[0158] The acquisition module 205 is configured to acquire the input current, the rotational speed, and the target torque before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the rotational speed of the motor.

[0159] In one application scenario, the torque determination module 201 is further configured to:

[0160] Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, motor parameters are determined according to the input current, the motor parameters including flux linkage and inductance. The first torque is determined according to the input current, the number of magnetic pole pairs and the motor parameters.

[0161] In another application scenario, the torque determination module 201 is further configured to:

[0162] Before determining the second torque according to the output power and the rotational speed of the motor, the input voltage of the motor is determined according to the input current, and the output power is determined according to the input voltage and the input current.

[0163] Figure 10 is a block diagram of a device for determining motor torque according to an exemplary embodiment. Figure 10 As shown, the device 200 further includes:

[0164] The sampling module 206 is used to sample the calibrated torque range of the motor to obtain a first number of sample target torques, and to sample the calibrated speed range of the motor to obtain a second number of sample speeds before determining the first torque based on the input current and the number of magnetic pole pairs of the motor and determining the second torque based on the output power and speed of the motor.

[0165] The combining module 207 is used to combine the first number of sample target torques and the second number of sample speeds to obtain a third number of groups of input parameters, where the third number is the product of the first number and the second number, and each group of input parameters includes a sample target torque and a sample speed.

[0166] The torque determination module 201 is also used to determine, for each set of input parameters, a first sample torque corresponding to the set of input parameters based on the control current corresponding to the sample target torque included in the set of input parameters and the number of magnetic poles, and to determine a second sample torque corresponding to the set of input parameters based on the sample output power and the sample speed included in the set of input parameters, where the sample output power is determined based on the control current.

[0167] The torque difference determination module 202 is further configured to determine a first sample torque difference and a second sample torque difference corresponding to the set of input parameters based on the sample target torque included in the set of input parameters and the first sample torque and the second sample torque corresponding to the set of input parameters.

[0168] The first processing module 203 is further configured to determine a comprehensive sample torque difference corresponding to the set of input parameters according to the first sample torque difference and the second sample torque difference corresponding to the set of input parameters in accordance with the first initial corresponding relationship.

[0169] The first fitting module 208 is used to fit the comprehensive sample torque difference corresponding to each set of input parameters using the third number of groups of input parameters to obtain a first corresponding relationship, which is used to determine the comprehensive torque difference based on the first torque difference and the second torque difference.

[0170] Figure 11 is a block diagram of a device for determining motor torque according to an exemplary embodiment. Figure 11 As shown, the second processing module 204 is further used to determine the output sample torque corresponding to the group of input parameters according to the first sample torque, the second sample torque and the comprehensive sample torque difference corresponding to the group of input parameters for each group of input parameters according to the second initial corresponding relationship after fitting the third number group of input parameters and the comprehensive sample torque difference corresponding to the group of input parameters to obtain the first corresponding relationship.

[0171] The apparatus 200 further includes:

[0172] The second fitting module 209 is used to fit the output sample torque corresponding to each set of input parameters using the third number of groups of input parameters to obtain a second corresponding relationship, and the second corresponding relationship is used to determine the output torque according to the first torque, the second torque and the comprehensive torque difference.

[0173] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0174] In summary, the present disclosure first determines a first torque based on the input current and pole pair number of the motor, and determines a second torque based on the output power and speed of the motor. It then determines a first torque difference based on the first torque and the current target torque of the motor, and determines a second torque difference based on the second torque and the target torque. It then determines a comprehensive torque difference based on the first torque difference and the second torque difference. Finally, it determines the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference. The present disclosure obtains a comprehensive torque difference based on the first torque difference and the second torque difference, and further obtains the output torque of the motor based on the first torque, the second torque, and the comprehensive torque difference, thereby improving the accuracy of determining the output torque of the motor.

[0175] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0176] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0177] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for determining motor torque, characterized in that: The method comprises: Determine the first torque according to the input current and the number of magnetic pole pairs of the motor, and determine the second torque according to the output power and the speed of the motor; determining a first torque difference according to the first torque and a current target torque of the motor, and determining a second torque difference according to the second torque and the target torque; determining a comprehensive torque difference based on the first torque difference and the second torque difference; determining an output torque of the motor according to the first torque, the second torque and the comprehensive torque difference; Determining the output torque of the motor according to the first torque, the second torque and the comprehensive torque difference includes: The output torque of the motor is determined according to the first torque, the second torque, the comprehensive torque difference and a preset corresponding relationship; the preset corresponding relationship includes the corresponding relationship between the first torque, the second torque, the comprehensive torque difference and the output torque of the motor.

2. The method according to claim 1, characterized in that Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, and determining the second torque according to the output power and the speed of the motor, the method further includes: The input current, the rotational speed, and the target torque are obtained.

3. The method according to claim 2, characterized in that Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, the method further includes: Determining motor parameters according to the input current, the motor parameters including flux linkage and inductance; The determining of the first torque according to the input current and the number of magnetic pole pairs of the motor includes: The first torque is determined according to the input current, the number of magnetic pole pairs, and the motor parameters.

4. The method according to claim 2, characterized in that Before determining the second torque according to the output power and the rotational speed of the motor, the method further includes: determining an input voltage of the motor according to the input current; The output power is determined according to the input voltage and the input current.

5. The method according to claim 1, wherein Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, and determining the second torque according to the output power and the speed of the motor, the method further includes: Sampling a calibrated torque range of the motor to obtain a first number of sample target torques, and sampling a calibrated speed range of the motor to obtain a second number of sample speeds; combining the first number of sample target torques and the second number of sample speeds to obtain a third number of groups of input parameters, where the third number is the product of the first number and the second number, and each group of input parameters includes one sample target torque and one sample speed; For each set of input parameters, determining a first sample torque corresponding to the set of input parameters based on the control current corresponding to the sample target torque included in the set of input parameters and the number of magnetic pole pairs, and determining a second sample torque corresponding to the set of input parameters based on a sample output power and the sample speed included in the set of input parameters, wherein the sample output power is determined based on the control current; Determining a first sample torque difference and a second sample torque difference corresponding to the set of input parameters based on the sample target torque included in the set of input parameters and the first sample torque and the second sample torque corresponding to the set of input parameters; Determining a comprehensive sample torque difference corresponding to the set of input parameters based on the first sample torque difference and the second sample torque difference corresponding to the set of input parameters according to the first initial corresponding relationship; The third number group of input parameters and the comprehensive sample torque difference corresponding to each group of input parameters are fitted to obtain a first corresponding relationship, which is used to determine the comprehensive torque difference according to the first torque difference and the second torque difference.

6. The method according to claim 5, characterized in that After fitting the integrated sample torque differences corresponding to each set of input parameters using the third number of groups to obtain a first corresponding relationship, the method further includes: For each set of input parameters, according to the second initial corresponding relationship, the output sample torque corresponding to the set of input parameters is determined based on the first sample torque, the second sample torque, and the comprehensive sample torque difference; The input parameters of the third group are fitted with the output sample torque corresponding to each group of the input parameters to obtain a second corresponding relationship, which is used to determine the output torque based on the first torque, the second torque and the comprehensive torque difference.

7. A device for determining motor torque, characterized in that: The device comprises: a torque determination module, configured to determine a first torque according to an input current and a number of magnetic pole pairs of the motor, and to determine a second torque according to an output power and a rotational speed of the motor; a torque difference determining module, configured to determine a first torque difference according to the first torque and a current target torque of the motor, and to determine a second torque difference according to the second torque and the target torque; a first processing module, configured to determine a comprehensive torque difference based on the first torque difference and the second torque difference; a second processing module, configured to determine an output torque of the motor according to the first torque, the second torque and the comprehensive torque difference; The second processing module is used to determine the output torque of the motor based on the first torque, the second torque, the comprehensive torque difference and a preset corresponding relationship; the preset corresponding relationship includes the corresponding relationship between the first torque, the second torque, the comprehensive torque difference and the output torque of the motor.

8. The device according to claim 7, characterized in that The device further comprises: An acquisition module is used to acquire the input current, the rotational speed and the target torque before determining the first torque according to the input current and the number of magnetic pole pairs of the motor and determining the second torque according to the output power and the rotational speed of the motor.

9. The device according to claim 8, characterized in that The torque determination module is used to: Before determining the first torque according to the input current and the number of magnetic pole pairs of the motor, motor parameters are determined according to the input current, and the motor parameters include magnetic flux and inductance; the first torque is determined according to the input current, the number of magnetic pole pairs and the motor parameters.

10. The device according to claim 8, characterized in that The torque determination module is used to: Before determining the second torque according to the output power and the rotational speed of the motor, the input voltage of the motor is determined according to the input current; and the output power is determined according to the input voltage and the input current.

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