Torque acquisition method and device, motor controller, and readable storage medium

Abstract

Embodiments of the present application provide a method and apparatus for acquiring torque, a motor controller, and a readable storage medium. The torque acquisition method includes: acquiring the motor speed; acquiring the motor current; acquiring the motor flux; determining the motor's electromagnetic torque based on the current and flux; and inputting the speed and electromagnetic torque into a preset state observer to obtain an observed value of the motor's actual output torque, output by the state observer. This acquisition method is designed to efficiently, simply, and accurately acquire the actual output torque.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a method and device for obtaining torque, a motor controller, and a readable storage medium. Background Art

[0002] New energy vehicle powertrain systems primarily include three-phase permanent magnet synchronous motors (PMSMs), and some three-phase induction motors. Typically, torque control is employed to optimize the drive motors in these vehicles, ensuring optimal operation during vehicle operation, such as starting, acceleration, deceleration, and braking. The actual output torque of the drive motor is a crucial reference variable, fed back to the vehicle controller for safe operation and protection, as well as for fault diagnosis and protection strategy implementation.

[0003] In the prior art, actual output torque can be obtained through various methods: sensor sampling method, power balance method, flux estimation method, etc. These methods cannot achieve effective and simple acquisition of output torque, or cannot achieve accurate acquisition of output torque. Summary of the Invention

[0004] The purpose of this application is to provide a torque acquisition method and device, a motor controller, and a readable storage medium to achieve effective, simple and accurate acquisition of actual output torque.

[0005] In a first aspect, the present application provides a method for obtaining torque, comprising: obtaining the rotational speed of a motor; obtaining the current of the motor; obtaining the magnetic flux of the motor; determining the electromagnetic torque of the motor based on the current and the magnetic flux; inputting the rotational speed and the electromagnetic torque into a preset state observer, and obtaining an observed value of the actual output torque of the motor output by the state observer.

[0006] In this application, compared to the prior art, when determining the actual output torque, the motor parameters acquired include: motor speed, motor flux, and motor current. These three parameters can be acquired through a sampling module inherent in the drive system, or through simple calculations based on the parameters acquired by the sampling module. This eliminates the need for an additional parameter acquisition module in the drive system, thereby enabling efficient, simple, and cost-effective acquisition of the actual output torque. Furthermore, based on the speed and current, the electromagnetic torque is first determined. These speed and electromagnetic torque are then input into a preset state observer, resulting in the observed value of the motor's actual output torque output by the state observer. The observed value of the actual output torque output by the state observer is relatively accurate, enabling accurate and reliable acquisition of the actual output torque.

[0007] As a possible implementation, the preset state observer outputs an observed value of the actual output torque of the motor based on the following calculation formula: Among them, w m is the rotational speed, T elc is the electromagnetic torque, is the observed value of the speed, B is the damping coefficient of the motor, J is the moment of inertia of the motor, is the derivative of the observed value of the rotational speed, is the observed value of the actual output torque, is the derivative of the observed value of the actual output torque, L1 is a preset first control parameter, and L2 is a preset second control parameter; the observed value of the speed is determined by integrating the derivative of the observed value of the speed.

[0008] In the present application, the above calculation formula corresponds to a Luenberger observer, and based on the speed and electromagnetic torque of the motor, the actual output torque can be accurately and reliably obtained through the Luenberger observer.

[0009] As a possible implementation, the current includes: q-axis current and d-axis current, the magnetic flux includes q-axis magnetic flux and d-axis magnetic flux, and determining the electromagnetic torque of the motor based on the current and the magnetic flux includes: determining the electromagnetic torque of the motor based on the current, the magnetic flux and a preset electromagnetic torque calculation formula; the electromagnetic torque calculation formula is expressed as: T elc =1.5*Pn*(Ψ d *iq-Ψ q *id); where T elc is the electromagnetic torque, Pn is the number of pole pairs of the motor, iq is the q-axis current, id is the d-axis current, Ψ q is the q-axis magnetic flux, Ψ d is the d-axis magnetic flux.

[0010] In the present application, effective determination of the electromagnetic torque is achieved based on the d-axis and q-axis currents, as well as the d-axis and q-axis flux linkages, and a preset electromagnetic torque calculation formula.

[0011] As a possible implementation manner, the current includes: q-axis current and d-axis current, the magnetic flux includes q-axis magnetic flux and d-axis magnetic flux, and obtaining the magnetic flux of the motor includes: obtaining the internal resistance of the winding of the motor; determining the q-axis voltage based on the q-axis current and a preset q-axis current, and determining the d-axis voltage based on the d-axis current and a preset d-axis current; determining the d-axis magnetic flux based on the internal resistance of the winding, the speed and the q-axis voltage, and determining the q-axis magnetic flux based on the internal resistance of the winding, the speed and the d-axis voltage.

[0012] In the present application, the corresponding two-axis voltages are determined respectively by the two-axis currents of the motor; based on the corresponding two-axis voltages, speed and internal resistance of the winding, the corresponding two-axis magnetic flux is effectively determined.

[0013] As a possible implementation, the d-axis magnetic flux is expressed as: d =(uq-Rs*iq) / w m , the q-axis magnetic flux is expressed as: q =(-ud+Rs*id) / w m ; Wherein, Rs is the internal resistance of the winding, w m is the rotational speed, uq is the q-axis voltage, and ud is the d-axis voltage.

[0014] In the present application, based on the preset calculation formula of the magnetic flux of the corresponding axis, and the obtained rotational speed and voltage of the corresponding axis, the effective determination of the magnetic flux of the corresponding two axes is achieved.

[0015] As a possible implementation, obtaining the current of the motor includes: obtaining the three-phase current of the motor and the rotor angle of the motor; and determining the two-phase current of the motor according to the three-phase current, the rotor angle and a preset coordinate transformation algorithm.

[0016] In this application, based on the three-phase current and rotor angle of the motor and a preset coordinate transformation algorithm, the two-phase current of the motor is effectively determined, which facilitates the subsequent application of the two-phase current.

[0017] As a possible implementation method, the acquisition method also includes: acquiring state information of the motor; acquiring the wind friction of the motor at the speed; based on the state information, correcting the observed value of the actual output torque according to the wind friction to obtain the corrected actual output torque.

[0018] In this application, by obtaining the state information of the motor and the wind friction force, the observed value of the actual output torque is corrected to further improve the accuracy of the actual output torque.

[0019] As a possible implementation method, based on the state information, the observed value of the actual output torque is corrected according to the wind friction force to obtain the corrected actual output torque, including: when it is determined that the state information is: the motor is in the electric state and the motor is rotating forward, the observed value of the actual output torque is subtracted from the wind friction force to obtain the corrected actual output torque.

[0020] In this application, when it is determined that the motor is in the electric state and the motor is rotating forward, the wind friction will reduce the actual output torque. By subtracting the observed value of the actual output torque from the wind friction, a more accurate actual output torque can be obtained.

[0021] As a possible implementation method, based on the state information, the observed value of the actual output torque is corrected according to the wind friction force to obtain the corrected actual output torque, including: when it is determined that the state information is: the motor is in the electric state and the motor is reversed, the observed value of the actual output torque is added to the wind friction force to obtain the corrected actual output torque.

[0022] In this application, when it is determined that the motor is in the electric state and the motor is reversed, the wind friction will increase the actual output torque. By adding the observed value of the actual output torque to the wind friction, a more accurate actual output torque is obtained.

[0023] As a possible implementation method, the acquisition method also includes: acquiring the temperature of the motor; determining the deviation coefficient corresponding to the temperature based on the temperature and a preset correspondence; the preset correspondence is the correspondence between the temperature and the deviation coefficient; and correcting the observed value of the actual output torque based on the deviation coefficient corresponding to the temperature to obtain the corrected actual output torque.

[0024] In this application, the correspondence between the preset temperature and the deviation coefficient is determined based on the temperature of the motor. The observed value of the actual output torque is corrected by the deviation coefficient to further improve the accuracy of the actual output torque.

[0025] As a possible implementation, the corrected actual output torque is expressed as: Wherein, K is the deviation coefficient corresponding to the temperature, is the observed value of the actual output torque.

[0026] In the present application, the relationship between the preset deviation coefficient and the observed value of the actual output torque is used to effectively determine the corrected actual output torque, thereby improving the accuracy of the actual output torque.

[0027] In a second aspect, the present application provides a torque acquisition device, comprising: various functional modules for implementing the torque acquisition method described in the first aspect and any possible implementation manner of the first aspect.

[0028] In a third aspect, the present application provides a motor controller comprising: a processor; and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can execute the torque acquisition method described in the first aspect and any possible implementation of the first aspect.

[0029] In a fourth aspect, the present application provides a vehicle comprising: a drive motor and a motor controller as described in the third aspect.

[0030] In a fifth aspect, the present application provides a readable storage medium having a computer program stored thereon. When the computer program is run by a computer, the method for obtaining torque as described in the first aspect and any possible implementation of the first aspect is executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0032] Figure 1 This is a structural block diagram of a drive system disclosed in one embodiment of the present application;

[0033] Figure 2 This is an example diagram of a circuit structure of a drive system disclosed in one embodiment of the present application;

[0034] Figure 3 This is a flow chart of a method for obtaining torque disclosed in one embodiment of the present application;

[0035] Figure 4 This is a schematic structural diagram of a torque acquisition device disclosed in one embodiment of the present application;

[0036] Figure 5 This is a structural diagram of a motor controller disclosed in one embodiment of the present application.

[0037] In the drawings, the drawings are not drawn to scale.

[0038] Marking description: 10-drive system; 11-motor; 12-motor controller; 120-processor; 121-storage area; 122-communication module; 13-sampling module; 131-current sampling module; 132-speed and angle sampling module; 133-temperature sampling module; 400-torque acquisition device; 410-acquisition module; 420-processing module. DETAILED DESCRIPTION

[0039] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0040] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0041] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0042] The technical solution provided in the embodiments of the present application can be used to control a drive motor, wherein the drive motor can be a drive motor in a new energy vehicle drive system, and thus the drive motor can be a three-phase permanent magnet synchronous motor or a three-phase induction motor.

[0043] When controlling the drive motor of a new energy vehicle, a torque mode can be used. In this mode, the actual output torque of the drive motor must be obtained first. Only then can the vehicle controller effectively control the drive motor based on the actual output torque. The acquisition of the actual output torque relies on the motor controller of the drive motor.

[0044] For application scenarios based on new energy vehicles, please refer to Figure 1 , is a schematic diagram of a drive system 10 provided in an embodiment of the present application, Figure 1 In the embodiment, the driving system 10 includes a motor 11 , a motor controller 12 and a sampling module 13 .

[0045] The sampling module 13 includes a current sampling module 131 , a rotation speed and angle sampling module 132 , and a temperature sampling module 133 .

[0046] The current sampling module 131 is used to collect motor current. The speed and angle sampling module 132 is used to collect motor speed and rotor angle. The temperature sampling module 133 is used to collect motor temperature, such as the temperature of the motor windings. The hardware implementation of each sampling module 13 refers to mature technologies in the field and is not described in detail in this embodiment.

[0047] The sampling module 13 is installed on the motor 11 or connected to the motor 11 according to the corresponding sampling method. For example, if the temperature sampling module 133 needs to collect the winding temperature value of the motor 11 in real time, it is installed on the winding of the motor 11. For another example, if the speed and angle sampling module 132 needs to collect the rotor speed and angle of the motor 11, it is physically connected to the rotor of the motor 11.

[0048] The motor controller 12 is connected to the sampling module 13 , and the sampling module 13 sends the collected data to the motor controller 12 , and then the motor controller 12 determines the torque according to the torque acquisition method provided in the embodiment of the present application.

[0049] It can be understood that the motor controller 12 is also connected to the vehicle controller of the new energy vehicle to transmit the obtained actual output torque to the vehicle controller.

[0050] The motor 11 and the motor controller 12 are also connected to each other to enable the motor controller 12 to perform various controls on the motor 11 .

[0051] For easier understanding, please refer to Figure 2 , is a circuit structure example diagram of a drive system 10 provided in an embodiment of the present application, Figure 2 In the example, the motor 11 is the drive motor, the temperature sampling module 133 is an NTC (Negative Temperature Coefficient) resistor, the current sampling module 131 collects three-phase currents respectively, and the speed and angle sampling module 132 collects the speed and angle of the entire drive motor. Figure 2 In the figure, only the NTC resistor is shown, and the current sampling module 131 and the speed and angle sampling module 132 are not shown.

[0052] The NTC resistor, the current sampling module 131 and the speed and angle sampling module 132 respectively send the collected information to the motor controller 12, which processes it.

[0053] The motor controller 12 implements its corresponding data processing through built-in algorithms such as overall control algorithm, torque estimation and correction, temperature sampling, coordinate transformation, etc.

[0054] exist Figure 2 The drive system 10 also includes modules such as a battery pack, an inverter, a capacitor, and a power and temperature acquisition module. These modules are basic modules in the drive system 10 and will not be introduced in detail here.

[0055] Combined with the introduction of the above application scenarios, please refer to Figure 3 , is a flow chart of a method for obtaining torque provided in an embodiment of the present application. The hardware environment corresponding to the method is the motor controller 12. The method includes:

[0056] Step 310 : Obtain the rotation speed of the motor 11 .

[0057] Step 320 : Obtain the current of the motor 11 .

[0058] Step 330 : Obtain the magnetic flux of the motor 11 .

[0059] Step 340: Determine the electromagnetic torque of the motor according to the current and the flux.

[0060] Step 350: Input the rotational speed and electromagnetic torque into a preset state observer to obtain an observed value of the actual output torque of the motor 11 output by the state observer.

[0061] In the embodiment of the present application, compared to the prior art, when determining the actual output torque, the motor parameters obtained include: the speed of motor 11, the flux of motor 11, and the motor current. These three parameters can be collected by sampling module 13, or obtained by performing simple calculations on the parameters collected by sampling module 13, eliminating the need to add an additional parameter collection module to drive system 10. Thus, effective, simple, and low-cost acquisition of the actual output torque can be achieved. Furthermore, based on the speed and current, the electromagnetic torque is first determined, and then the speed and electromagnetic torque are input into a preset state observer. The observed value of the actual output torque of motor 11 output by the state observer can be obtained. The observed value of the actual output torque output by the state observer is relatively accurate, thus enabling accurate and reliable acquisition of the actual output torque.

[0062] Next, the detailed implementation of the acquisition method is introduced.

[0063] In step 310 , the speed of the motor can be acquired through the speed and angle sampling module 132 .

[0064] In step 320, the current can be acquired through the current sampling module 131. The drive motor is usually a three-phase drive motor, and accordingly, the current sampling module 131 is a three-phase current sampling module, and the current it collects is a three-phase current.

[0065] Therefore, in step 320, the motor controller 12 may first obtain the three-phase currents collected by the current sampling module 131, and then process the three-phase currents to obtain two-phase currents for subsequent applications. Accordingly, as an optional embodiment, step 320 includes: obtaining the three-phase currents of the motor 11 and the rotor angle of the motor 11; and determining the two-phase currents of the motor 11 based on the three-phase currents, the rotor angle, and a preset coordinate transformation algorithm.

[0066] The three-phase current of the motor 11 is collected by the current sampling module 131 and can be directly obtained from the current sampling module 131. The rotor angle of the motor 11 is collected by the speed and angle sampling module 132 and can be directly obtained from the speed and angle sampling module 132.

[0067] Assuming that the three-phase current is the actual current of the three phases U, V, and W, it can be transformed from the abc three-phase coordinate system to the dq axis rectangular coordinate system through the preset coordinate transformation algorithm to obtain the two-phase current of the d axis and q axis.

[0068] Assuming that the three-phase currents are iu, iv, and iw, the converted two-phase currents are id and iq, and the rotor angle is θ, then as an optional implementation, the preset coordinate transformation algorithm can be expressed as:

[0069] In this embodiment, based on the three-phase current and rotor angle of the motor 11 and a preset coordinate transformation algorithm, the two-phase current of the motor 11 is effectively determined, which facilitates subsequent application of the two-phase current.

[0070] In step 330, the flux of the motor 11 is acquired. This parameter cannot be directly acquired by the sampling module 13, but can be determined using parameters acquired by the sampling module 13. In conjunction with the implementation of step 320, the current ultimately determined in step 320 includes the q-axis current and the d-axis current. Accordingly, the flux acquired in step 330 also includes the q-axis flux and the d-axis flux.

[0071] As an optional embodiment, step 330 includes: obtaining the internal resistance of the winding of the motor 11; determining the q-axis voltage based on the q-axis current and the preset q-axis current, and determining the d-axis voltage based on the d-axis current and the preset d-axis current; determining the d-axis magnetic flux based on the internal resistance, speed and q-axis voltage of the winding, and determining the q-axis magnetic flux based on the internal resistance, speed and the d-axis voltage of the winding.

[0072] The internal resistance of the winding can be determined by the winding temperature collected by the temperature sampling module 13 and the preset corresponding relationship between the winding and the temperature.

[0073] As an optional implementation, assuming the internal resistance of the winding is Rs, it can be expressed as: R s =R0*(1+0.00393*(temp-25)), where R0 is the internal resistance of the winding at 25 degrees Celsius, and temp is the real-time winding temperature collected by the temperature sampling module 13.

[0074] The preset q-axis current is a given q-axis current, which may vary in different application scenarios. Similarly, the preset d-axis current is a given d-axis current, which may vary in different application scenarios.

[0075] The q-axis current and the d-axis current acquired in step 320 may be understood as the actual q-axis current and the actual d-axis current.

[0076] Based on the actual q-axis current and the preset q-axis current, the current error between the two is controlled and output through proportional integration to obtain the corresponding q-axis voltage; based on the actual d-axis current and the preset d-axis current, the current error between the two is controlled and output through proportional integration to obtain the corresponding d-axis voltage.

[0077] After the internal resistance, d-axis voltage and q-axis voltage of the winding are determined, the q-axis magnetic flux and d-axis magnetic flux can be determined in combination with the speed, thereby effectively determining the magnetic flux.

[0078] As an optional embodiment, the d-axis flux is expressed as: d =(uq-Rs*iq) / w m , the q-axis magnetic flux is expressed as: q =(-ud+Rs*id) / w m ; Among them, Rs is the internal resistance of the winding, w m is the speed, uq is the q-axis voltage, and ud is the d-axis voltage.

[0079] In the embodiment of the present application, based on the preset calculation formula of the magnetic flux of the corresponding axis, and the obtained rotational speed and voltage of the corresponding axis, the effective determination of the magnetic flux of the corresponding two axes is achieved.

[0080] It can be understood that in steps 310 to 330, the speed, current and magnetic flux are obtained respectively. In practical applications, the execution order of these three steps is not limited. The three steps can have a corresponding order or can be executed simultaneously.

[0081] In step 340, the electromagnetic torque of the motor 11 is determined based on the current and flux. In combination with the two-phase current and two-phase flux described in the above embodiment, as an optional implementation, step 340 includes: determining the electromagnetic torque of the motor 11 based on the current, flux, and a preset electromagnetic torque calculation formula; the electromagnetic torque calculation formula is expressed as: T elc =1.5*Pn*(Ψ d *iq-Ψ q *id); where T elc is the electromagnetic torque, Pn is the number of pole pairs of the motor, iq is the q-axis current, id is the d-axis current, Ψ q is the q-axis magnetic flux, Ψ d is the d-axis magnetic flux.

[0082] The number of pole pairs of the motor is known information, and the two-phase currents and two-phase flux linkages have been determined in steps 320 and 330, respectively. Substituting each parameter into the calculation formula, the electromagnetic torque can be determined.

[0083] In the embodiment of the present application, effective determination of the electromagnetic torque is achieved based on the two-phase current and the two-phase flux, and a preset electromagnetic torque calculation formula.

[0084] After the electromagnetic torque is determined in step 340 , in step 350 , the rotational speed and the electromagnetic torque are input into a preset state observer to obtain an observed value of the actual output torque of the motor 11 output by the state observer.

[0085] Among them, the preset state observer is an observer constructed according to the torque state space. The torque state space can be established based on the mechanical motion equation of the drive motor, and the drive motor is the motor 11.

[0086] In this embodiment of the present application, the preset state observer may be a sliding mode observer, a Romberg observer, or the like. Different state observers correspond to the same mechanical motion equations for the drive motor, but some parameters may differ when constructing the torque state space. In step 350, the preset state observer refers to a state observer that has already completed the construction of the state torque space and can directly output the observed value of the actual output torque.

[0087] Next, the construction of the torque state space of the Lumberg observer is introduced as an example. Other state observers can also achieve corresponding constructions by referring to the construction of the torque state space of the Lumberg observer, and can ultimately be applied to the determination of the actual output torque.

[0088] The mechanical motion equation of the drive motor is Among them, w m is the real-time speed of the driving motor, i.e., the speed collected by the speed and angle sampling module 132; Telc is the electromagnetic torque of the driving motor, that is, the electromagnetic torque determined in step 330; T load is the actual output torque of the drive motor, which is a parameter that needs to be determined; B is the damping coefficient of the drive motor, which is known information; J is the moment of inertia of the drive motor, which is also known information.

[0089] According to the mechanical motion equation, the corresponding torque state space can be established: the state quantity, including the drive motor speed and the actual output torque: Input quantity is electromagnetic torque: i = T elc ; Output, which is the speed of the drive motor: o = w m .

[0090] When the control frequency of the motor controller 12 is very high, the sampling period is in the microsecond level. Within the microsecond level, the actual output torque can be considered to be a constant value. Therefore, the state space can be further expressed as follows:

[0091]

[0092] The general form corresponding to the above representation is expressed as: Among them, A, B, C, and D are preset parameters of the state observer, which depend on the specific state observer. It should be noted that B in the preset parameters here is different from the damping coefficient B in the aforementioned embodiment.

[0093] Further rewriting this general form, we can obtain the calculation formula of the preset state observer, which is expressed as: in, is the derivative of the observed value of the speed, is the observed value of the actual output torque, is the derivative of the observed value of the actual output torque, L1 is the preset first control parameter, and L2 is the preset second control parameter; the observed value of the speed can be determined by integrating the derivative of the observed value of the speed.

[0094] The preset first control parameter and the preset second control parameter are fixed control parameters of the motor 11 , and their specific values ​​are not limited here.

[0095] In step 350, the speed and electromagnetic torque are input into a pre-set Lumberg observer. Based on the aforementioned formula, the Lumberg observer determines the observed value of the actual output torque, which is then output. The observed value of the actual output torque can be understood as the value obtained by correcting the theoretical actual output torque using the state observer; it can also be understood as the actual output torque observed by the state observer.

[0096] In the embodiment of the present application, the actual output torque is accurately and reliably obtained through the Romberg observer.

[0097] After obtaining the observed value of the actual output torque outputted by the state observer in step 350, the motor controller 12 may transmit the observed value of the actual output torque to the vehicle controller, which then performs subsequent control. However, considering that the actual output torque may be affected by other external factors, such as wind friction and temperature, in this embodiment of the present application, the observed value of the actual output torque may be corrected to obtain a more accurate actual output torque.

[0098] As a first optional implementation, the acquisition method also includes: acquiring status information of the motor 11; acquiring the wind friction of the motor 11 at the rotation speed; based on the status information, correcting the observed value of the actual output torque according to the wind friction to obtain the corrected actual output torque.

[0099] The state information and wind friction of the motor 11 can be measured by a dynamometer, so the motor controller 12 can obtain the state information and wind friction from the dynamometer.

[0100] The state information may include whether the motor 11 is in the motoring state or the feeding state, and whether the motor 11 is rotating forward or reverse. When the motor 11 is in the motoring state, the product of the actual output torque and the actual speed of the motor 11 is positive, and the motor 11 can rotate forward or reverse. When the motor 11 is in the feeding state, the speed of the motor 11 is in a decelerated state.

[0101] In this embodiment, by acquiring the state information of the motor 11 and the wind friction force, the observed value of the actual output torque is corrected, thereby further improving the accuracy of the actual output torque.

[0102] Based on different state information, the observed value of the actual output torque can be correspondingly corrected. As an optional embodiment, based on the state information, the observed value of the actual output torque is corrected according to the wind friction force to obtain the corrected actual output torque, including: when the state information is determined to be: the motor 11 is in the electric state and the motor 11 is rotating forward, the observed value of the actual output torque is subtracted from the wind friction force to obtain the corrected actual output torque.

[0103] In this embodiment, when it is determined that the motor 11 is in the electric state and the motor is rotating forward, the wind friction will reduce the actual output torque. By subtracting the observed value of the actual output torque from the wind friction, a more accurate actual output torque can be obtained.

[0104] As another optional implementation, based on the state information, the observed value of the actual output torque is corrected according to the wind friction force to obtain the corrected actual output torque, including: when the state information is determined as: the motor 11 is in the electric state and the motor 11 is reversed, the observed value of the actual output torque is added to the wind friction force to obtain the corrected actual output torque.

[0105] In this embodiment, when it is determined that the motor is in the electric state and the motor is reversed, the wind friction will increase the actual output torque. By adding the observed value of the actual output torque to the wind friction, a more accurate actual output torque is obtained.

[0106] In addition, when the motor 11 is in the power feeding state, the influence of wind friction on the actual output torque is small, so the observed value of the actual output torque does not need to be corrected.

[0107] In addition to wind friction affecting actual output torque, the temperature of the drive motor can vary significantly when operating in different operating conditions, which can also affect actual output torque. Therefore, as a second optional correction method, the acquisition method further includes: obtaining the temperature of the motor 11; determining a temperature-dependent deviation coefficient based on a predetermined relationship between the temperature and the deviation coefficient; the predetermined relationship being the relationship between the temperature and the deviation coefficient; and correcting the observed actual output torque based on the temperature-dependent deviation coefficient to obtain a corrected actual output torque.

[0108] The temperature of the motor 11 is the temperature collected by the temperature sampling module 13 . Therefore, the motor controller 12 can obtain the temperature of the motor 11 from the temperature sampling module 13 .

[0109] The preset correspondence is a correspondence between temperature and the deviation coefficient. As an optional embodiment, this correspondence is preset by testing the observer's estimated torque under different temperature conditions. The estimated torque is the observed value of the actual output torque output by the observer, and the actual output torque of the motor 11 is measured using a dynamometer. The deviation coefficient corresponding to different temperatures is then determined based on the estimated torque and the actual output torque.

[0110] Specifically, the dynamometer operates the motor under test at its rated speed in speed mode. The motor under test operates in torque mode and is given a rated torque command. The motor is then gradually heated from zero degrees Celsius to its maximum operating temperature. The observed and actual output torque values ​​are recorded at 10-degree intervals.

[0111] Furthermore, the deviation coefficient K can be expressed as: in, is the observed value of the actual output torque output by the observer, and Tact is the actual output torque measured by the dynamometer.

[0112] The corresponding relationship can be preset by storing the deviation coefficient K and the corresponding temperature in a corresponding relationship. When storing, the deviation coefficient K and the corresponding temperature can be made into a one-dimensional table to facilitate the application of the corresponding relationship.

[0113] Based on the preset corresponding relationship and the real-time temperature, the deviation coefficient corresponding to the real-time temperature is found in the corresponding relationship, and the observed value of the actual output torque can be corrected based on the corresponding deviation coefficient.

[0114] In an embodiment of the present application, the correspondence between the preset temperature and the deviation coefficient is determined based on the temperature of the motor 11. The observed value of the actual output torque is corrected by the deviation coefficient to further improve the accuracy of the actual output torque.

[0115] During correction, as an optional implementation, the corrected actual output torque is expressed as: Where K is the deviation coefficient corresponding to temperature, is the observed value of the actual output torque.

[0116] After correcting the observed value of the actual output torque according to the above formula, the corrected observed value of the actual output torque can be obtained.

[0117] The above two implementation methods correspond to the correction methods of the two influencing factors of wind friction and temperature respectively. In actual application, only one of the correction methods can be used to correct the observed value of the actual output torque, or the two correction methods can be combined to correct the observed value of the actual output torque. There is no limitation here.

[0118] Based on the same invention concept, please refer to Figure 4 In an embodiment of the present application, a torque acquisition device 400 is also provided, including: an acquisition module 410 and a processing module 420.

[0119] The acquisition module 410 is used to: obtain the rotational speed of the motor 11; obtain the current of the motor 11; obtain the magnetic flux of the motor 11; the processing module 420 is used to: determine the electromagnetic torque of the motor 11 based on the current and the magnetic flux; input the rotational speed and the electromagnetic torque into a preset state observer to obtain the observed value of the actual output torque of the motor 11 output by the state observer.

[0120] In the embodiment of the present application, the processing module 420 is specifically used to determine the electromagnetic torque of the motor 11 according to the current, the flux linkage and a preset electromagnetic torque calculation formula; the electromagnetic torque calculation formula is expressed as: Telc =1.5*Pn*(Ψ d *iq-Ψ q *id); where T elc is the electromagnetic torque, Pn is the number of pole pairs of the motor 11, iq is the q-axis current, id is the d-axis current, Ψ q is the q-axis magnetic flux, Ψ d is the d-axis magnetic flux.

[0121] In an embodiment of the present application, the acquisition module 410 is specifically used to: obtain the internal resistance of the winding of the motor 11; determine the q-axis voltage based on the q-axis current and the preset q-axis current, and determine the d-axis voltage based on the d-axis current and the preset d-axis current; determine the d-axis magnetic flux based on the internal resistance of the winding, the speed and the q-axis voltage, and determine the q-axis magnetic flux based on the internal resistance of the winding, the speed and the d-axis voltage.

[0122] In an embodiment of the present application, the acquisition module 410 is specifically used to: obtain the three-phase current of the motor 11 and the rotor angle of the motor 11; and determine the two-phase current of the motor 11 based on the three-phase current, the rotor angle and a preset coordinate transformation algorithm.

[0123] In an embodiment of the present application, the acquisition module 410 is also used to: obtain the status information of the motor 11; obtain the wind friction of the motor 11 at the speed; the processing module 420 is also used to: based on the status information, correct the observed value of the actual output torque according to the wind friction to obtain the corrected actual output torque.

[0124] In an embodiment of the present application, the processing module 420 is specifically used to: when it is determined that the state information is: the motor 11 is in the electric state and the motor 11 is rotating forward, subtract the observed value of the actual output torque from the wind friction force to obtain the corrected actual output torque.

[0125] In an embodiment of the present application, the processing module 420 is specifically used to: when it is determined that the state information is: the motor 11 is in the electric state and the motor 11 is reversed, add the observed value of the actual output torque to the wind friction force to obtain the corrected actual output torque.

[0126] In an embodiment of the present application, the acquisition module 410 is also used to: obtain the temperature of the motor 11; the processing module 420 is also used to: determine the deviation coefficient corresponding to the temperature based on the temperature and a preset correspondence; the preset correspondence is the correspondence between the temperature and the deviation coefficient; the observed value of the actual output torque is corrected according to the deviation coefficient corresponding to the temperature to obtain the corrected actual output torque.

[0127] The torque acquisition device 400 corresponds to the torque acquisition method in the aforementioned embodiment, and each functional module corresponds to each step of the torque acquisition method. Therefore, the implementation method of each functional module refers to the implementation method of each step and will not be repeated here.

[0128] Based on the same invention concept, please refer to Figure 5 The embodiment of the present application further provides a motor controller 12 , including: a processor 120 , a memory 121 , and a communication module 122 .

[0129] The processor 120, memory 121, and communication module 122 are electrically connected, directly or indirectly, to enable data transmission or exchange. For example, these components may be electrically connected via one or more communication buses or signal buses. Each torque acquisition method includes at least one software functional module that can be stored in the memory 121 in the form of software or firmware.

[0130] The processor 120 can be an integrated circuit chip with signal processing capabilities. The processor 120 can be a general-purpose processor, including a CPU (Central Processing Unit), an NP (Network Processor), etc.; it can also be a digital signal processor, an application-specific integrated circuit, an off-the-shelf programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor.

[0131] The memory 121 can store various software programs and modules, such as the program instructions / modules corresponding to the torque acquisition method and apparatus provided in the embodiments of the present application. The processor 120 executes the software programs and modules stored in the memory 121 to perform various functional applications and data processing, thereby implementing the technical solutions in the embodiments of the present application.

[0132] The memory 121 may include but is not limited to RAM (Random Access Memory), ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electric Erasable Programmable Read-Only Memory), etc.

[0133] The communication module 122 is used to realize the communication connection between the motor controller 12, the sampling module 13 and the vehicle controller, and can be: a wireless communication module, a Bluetooth communication module, a 4G / 5G communication module, etc.

[0134] I understand. Figure 5 The components shown are merely examples, and the motor controller 12 may include more components.

[0135] In an embodiment of the present application, a vehicle is further provided, including a drive motor 11 and a motor controller 12; or the drive system 10 described in the aforementioned embodiment.

[0136] The vehicle may be a new energy vehicle, and its drive motor may be a permanent magnet synchronous motor.

[0137] The vehicle may also include components such as a vehicle controller, a power battery, and a battery management system, which are not limited here.

[0138] In an embodiment of the present application, a readable storage medium is further provided, on which a computer program is stored. When the computer program is run by a computer, the torque acquisition method provided in the embodiment of the present application is executed.

[0139] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A method for obtaining torque, characterized in that: include: Get the motor speed; obtaining the current of the motor; Obtaining the magnetic flux of the motor; determining the electromagnetic torque of the motor according to the current and the flux linkage; Inputting the rotational speed and the electromagnetic torque into a preset state observer to obtain an observation value of the actual output torque of the motor output by the state observer; The preset state observer outputs the observed value of the actual output torque of the motor based on the following calculation formula: ， ； in, is the rotational speed, is the electromagnetic torque, is the observed value of the rotational speed, is the damping coefficient of the motor, is the moment of inertia of the motor, is the derivative of the observed value of the rotational speed, is the observed value of the actual output torque, is the derivative of the observed value of the actual output torque, is the preset first control parameter, is a preset second control parameter; The observed value of the rotational speed is determined by integrating a derivative of the observed value of the rotational speed.

2. The acquisition method according to claim 1, characterized in that The current includes: a q-axis current and a d-axis current, the flux includes a q-axis flux and a d-axis flux, and determining the electromagnetic torque of the motor according to the current and the flux includes: Determining the electromagnetic torque of the motor according to the current, the flux linkage and a preset electromagnetic torque calculation formula; The electromagnetic torque calculation formula is expressed as: ; in, is the electromagnetic torque, is the number of pole pairs of the motor, is the q-axis current, is the d-axis current, is the q-axis magnetic flux, is the d-axis magnetic flux.

3. The acquisition method according to claim 1, characterized in that The current includes: q-axis current and d-axis current, the magnetic flux includes q-axis magnetic flux and d-axis magnetic flux, and obtaining the magnetic flux of the motor includes: Obtaining the internal resistance of the winding of the motor; determining a q-axis voltage according to the q-axis current and a preset q-axis current, and determining a d-axis voltage according to the d-axis current and a preset d-axis current; The d-axis flux is determined according to the internal resistance of the winding, the rotational speed, and the q-axis voltage, and the q-axis flux is determined according to the internal resistance of the winding, the rotational speed, and the d-axis voltage.

4. The acquisition method according to claim 3, characterized in that The d-axis flux is expressed as: , the q-axis magnetic flux is expressed as: ; in, is the internal resistance of the winding, is the rotational speed, is the q-axis voltage, is the d-axis voltage.

5. The acquisition method according to claim 1, characterized in that The obtaining of the current of the motor includes: Obtaining the three-phase current of the motor and the rotor angle of the motor; The two-phase current of the motor is determined according to the three-phase current, the rotor angle and a preset coordinate transformation algorithm.

6. The acquisition method according to claim 1, characterized in that: The acquisition method further includes: Acquiring status information of the motor; Obtaining the wind friction force of the motor at the rotational speed; Based on the state information, the observed value of the actual output torque is corrected according to the wind friction force to obtain a corrected actual output torque.

7. The acquisition method according to claim 6, characterized in that: The step of correcting the observed value of the actual output torque based on the state information and according to the wind friction force to obtain the corrected actual output torque includes: When it is determined that the state information is that the motor is in the electric state and the motor is rotating forward, the observed value of the actual output torque is subtracted from the wind friction force to obtain a corrected actual output torque.

8. The acquisition method according to claim 6, characterized in that: The step of correcting the observed value of the actual output torque based on the state information and according to the wind friction force to obtain the corrected actual output torque includes: When it is determined that the state information is that the motor is in the electric state and the motor is reversed, the observed value of the actual output torque is added to the wind friction force to obtain a corrected actual output torque.

9. The acquisition method according to claim 1, characterized in that: The acquisition method further includes: obtaining the temperature of the motor; Determining a deviation coefficient corresponding to the temperature according to a preset correspondence between the temperature and the temperature; the preset correspondence is a correspondence between the temperature and the deviation coefficient; The observed value of the actual output torque is corrected according to the deviation coefficient corresponding to the temperature to obtain a corrected actual output torque.

10. The acquisition method according to claim 9, characterized in that: The corrected actual output torque is expressed as: Tact=(1-K)* ; Wherein, K is the deviation coefficient corresponding to the temperature, is the observed value of the actual output torque.

11. A torque acquisition device, characterized in that: include: An acquisition module is used to: acquire the rotation speed of the motor; acquire the current of the motor; Obtaining the magnetic flux of the motor; a processing module, configured to: determine the electromagnetic torque of the motor based on the current and the flux; input the speed and the electromagnetic torque into a preset state observer to obtain an observed value of the actual output torque of the motor output by the state observer; the preset state observer outputs the observed value of the actual output torque of the motor based on the following calculation formula: ， ； in, is the rotational speed, is the electromagnetic torque, is the observed value of the rotational speed, is the damping coefficient of the motor, is the moment of inertia of the motor, is the derivative of the observed value of the rotational speed, is the observed value of the actual output torque, is the derivative of the observed value of the actual output torque, is the preset first control parameter, is a preset second control parameter; The observed value of the rotational speed is determined by integrating a derivative of the observed value of the rotational speed.

12. The acquisition device according to claim 11, characterized in that The current includes: a q-axis current and a d-axis current, the flux includes a q-axis flux and a d-axis flux, and the processing module is specifically configured to: determine the electromagnetic torque of the motor according to the current, the flux, and a preset electromagnetic torque calculation formula; The electromagnetic torque calculation formula is expressed as: ; in, is the electromagnetic torque, is the number of pole pairs of the motor, is the q-axis current, is the d-axis current, is the q-axis magnetic flux, is the d-axis magnetic flux.

13. The acquisition device according to claim 11, characterized in that The current includes: q-axis current and d-axis current, the magnetic flux includes q-axis magnetic flux and d-axis magnetic flux, and the acquisition module is specifically used to: Obtaining the internal resistance of the winding of the motor; determining a q-axis voltage according to the q-axis current and a preset q-axis current, and determining a d-axis voltage according to the d-axis current and a preset d-axis current; The d-axis flux is determined according to the internal resistance of the winding, the rotational speed, and the q-axis voltage, and the q-axis flux is determined according to the internal resistance of the winding, the rotational speed, and the d-axis voltage.

14. The acquisition device according to claim 13, characterized in that The d-axis flux is expressed as: , the q-axis magnetic flux is expressed as: ; in, is the internal resistance of the winding, is the rotational speed, is the q-axis voltage, is the d-axis voltage.

15. The acquisition device according to claim 11, characterized in that The acquisition module is specifically used for: Obtaining the three-phase current of the motor and the rotor angle of the motor; The two-phase current of the motor is determined according to the three-phase current, the rotor angle and a preset coordinate transformation algorithm.

16. The acquisition device according to claim 11, characterized in that The acquisition module is further used to: acquire the state information of the motor; acquire the wind friction force of the motor at the speed; The processing module is further configured to: based on the state information, correct the observed value of the actual output torque according to the wind friction force to obtain a corrected actual output torque.

17. The acquisition device according to claim 16, characterized in that The processing module is specifically used for: When it is determined that the state information is that the motor is in the electric state and the motor is rotating forward, the observed value of the actual output torque is subtracted from the wind friction force to obtain a corrected actual output torque.

18. The acquisition device according to claim 16, characterized in that The processing module is specifically used for: When it is determined that the state information is that the motor is in the electric state and the motor is reversed, the observed value of the actual output torque is added to the wind friction force to obtain a corrected actual output torque.

19. The acquisition device according to claim 11, characterized in that The acquisition module is further used to: acquire the temperature of the motor; The processing module is further configured to: determine a deviation coefficient corresponding to the temperature according to a preset corresponding relationship between the temperature and the deviation coefficient; the preset corresponding relationship is a corresponding relationship between the temperature and the deviation coefficient; The observed value of the actual output torque is corrected according to the deviation coefficient corresponding to the temperature to obtain a corrected actual output torque.

20. The acquisition device according to claim 19, characterized in that The corrected actual output torque is expressed as: Tact=(1-K)* ; Wherein, K is the deviation coefficient corresponding to the temperature, is the observed value of the actual output torque.

21. A motor controller, characterized in that: include: processor; and a memory communicatively connected to the processor; The memory stores instructions that can be executed by the processor, and the instructions are executed by the processor so that the processor can execute the torque acquisition method according to any one of claims 1 to 10.

22. A readable storage medium, characterized in that The readable storage medium stores a computer program, and when the computer program is executed by a computer, the torque acquisition method according to any one of claims 1 to 10 is executed.

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