Filtering cut-off frequency determination method and driving motor control method

Abstract

The embodiment of the invention provides a filtering cut-off frequency determination method and a driving motor control method. The filter cut-off frequency determination method comprises the following steps: calculating a theoretical phase current frequency according to a target rotating speed of a driving motor in a current period, and calculating an estimated phase current frequency according to an estimated rotating speed of the driving motor in the current period; calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency; and performing weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient to obtain the filtering cut-off frequency of the current period. The filtering cut-off frequency determined based on the method is substantially determined based on the condition of predicting the actual rotating speed of the driving motor, so that the filtering cut-off frequency better conforms to the actual rotating speed characteristic of the driving motor, and the filtering cut-off frequency can be adaptively determined under the condition of rotating speed fluctuation; and the filtering precision and the filtering effect are optimized.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular to a method for determining a filter cutoff frequency and a method for controlling a drive motor. Background Art

[0002] Some vehicles use permanent magnet synchronous motors (PMSMs) as power sources for components such as water pumps and electric compressors. To reduce cost and motor weight, these PMSMs utilize a sensorless control strategy, calculating the motor rotor position based on electrical information such as the motor winding voltage and current.

[0003] In practical applications, after estimating the flux or back EMF of a permanent magnet synchronous motor using the aforementioned methods, a filter is needed to remove high-frequency jitter components to more accurately estimate the rotor position. Currently, the filter used in the industry is a first-order low-pass filter (LPF). The filtering effectiveness of a first-order low-pass filter is affected by its cutoff frequency. Current methods for determining the cutoff frequency include using the phase current frequency corresponding to the motor's maximum speed or the phase current frequency corresponding to the motor's current speed. However, using the phase current frequency corresponding to the motor's maximum speed to determine the cutoff frequency can result in large relative errors in current sampling within the motor's low speed range, leading to poor filtering effectiveness. If the first-order low-pass filter is no longer able to perform its filtering function effectively, it can directly lead to position estimation errors and motor shutdown. Using the phase current frequency corresponding to the motor's current speed to determine the cutoff frequency, because the phase current frequency varies with the motor speed, the cutoff frequency also varies continuously, increasing filter instability and errors in the calculation of the filter delay phase. Therefore, the cutoff frequencies determined by the aforementioned two methods are not applicable to all motor speed scenarios. Summary of the Invention

[0004] In order to solve the above technical problems, embodiments of the present disclosure provide a method for determining a filter cutoff frequency and a method for controlling a drive motor.

[0005] In a first aspect, an embodiment of the present disclosure provides a method for determining a filter cutoff frequency, comprising:

[0006] Calculating a theoretical phase current frequency according to a target rotational speed of the drive motor in a current cycle, and calculating an estimated phase current frequency according to an estimated rotational speed of the drive motor in the current cycle;

[0007] Calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency;

[0008] A weighted sum is performed based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filter cutoff frequency of the current cycle.

[0009] Optionally, before calculating the theoretical phase current frequency according to the target speed of the drive motor in the current cycle, the method further includes:

[0010] The target speed of the current cycle is calculated based on the requested speed and the target speed of the previous cycle.

[0011] Optionally, calculating the target speed of the current cycle according to the requested speed and the target speed of the previous cycle includes:

[0012] calculating a difference between the requested speed and a target speed in a previous cycle, and determining a speed acceleration based on the difference;

[0013] The target speed of the current cycle is calculated based on the target speed of the previous cycle and the speed acceleration.

[0014] Optionally, determining the rotational speed acceleration based on the difference includes:

[0015] When the difference is greater than 0, a first preset acceleration having the same direction as the target speed in the previous cycle is used as the speed acceleration;

[0016] When the difference is less than 0, a second preset acceleration in a direction opposite to the target speed in the previous cycle is used as the speed acceleration;

[0017] When the difference is 0, determining the rotational speed acceleration to be 0;

[0018] The magnitudes of the first preset acceleration and the second preset acceleration are preset.

[0019] Optionally, the calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency includes:

[0020] Obtaining a sum of the theoretical phase current frequency and the estimated phase current frequency;

[0021] The theoretical frequency weighting coefficient is determined based on a ratio of the theoretical phase current frequency to the sum value, and the estimated frequency weighting coefficient is determined based on a ratio of the estimated phase current frequency to the sum value.

[0022] Optionally, performing weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain the cutoff frequency includes:

[0023] use Get the cutoff frequency f cutoff , where c is a value greater than 1, k1 is the theoretical frequency weighting coefficient, f curr is the theoretical phase current frequency, k2 is the estimated frequency weighting coefficient, is the estimated phase current frequency.

[0024] In a second aspect, an embodiment of the present disclosure provides a drive motor control method, including:

[0025] Obtaining the motor flux or motor back electromotive force of the drive motor; determining the filter cutoff frequency using the method described above, and constructing a low-pass filter based on the filter cutoff frequency;

[0026] Using the low-pass filter to perform low-pass filtering on the motor flux or the motor back electromotive force to obtain filtered flux or filtered back electromotive force;

[0027] The rotor position of the drive motor is determined according to the filtered flux or the filtered back electromotive force.

[0028] In a third aspect, an embodiment of the present disclosure provides a device for determining a filter cutoff frequency, comprising:

[0029] a frequency calculation unit, configured to calculate a theoretical phase current frequency according to a target rotational speed of the drive motor in a current cycle, and to calculate an estimated phase current frequency according to an estimated rotational speed of the drive motor in the current cycle;

[0030] a weighting coefficient calculation unit, configured to calculate a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency;

[0031] The cutoff frequency determining unit is configured to obtain a filtering cutoff frequency by performing weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient.

[0032] In a fourth aspect, an embodiment of the present disclosure provides a drive motor control device, comprising:

[0033] An electromagnetic characteristic determination unit, used to obtain the motor flux or motor back electromotive force of the drive motor;

[0034] A filter determination unit, configured to determine a filter cutoff frequency using the aforementioned method, and construct a low-pass filter based on the filter cutoff frequency;

[0035] a filtering unit, configured to perform low-pass filtering on the motor flux or the motor back electromotive force using the low-pass filter to obtain a filtered flux or a filtered back electromotive force;

[0036] A rotor position determining unit is configured to determine the rotor position of the drive motor according to the filtered flux or the filtered back electromotive force.

[0037] In a fifth aspect, the present disclosure further provides a motor controller comprising a processor and a memory, wherein the memory is used to store a computer program; when the computer program is loaded by the processor, the processor executes the method described above.

[0038] The solution for determining the filter cutoff frequency provided by the embodiment of the present disclosure first determines the theoretical phase current frequency and the estimated phase current frequency of the drive motor in the current cycle, then calculates the corresponding theoretical frequency weighting coefficient and the estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency, and obtains the filter cutoff frequency of the current cycle by weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient. The filter cutoff frequency determined based on the above method is essentially determined based on the actual speed of the predicted drive motor. Therefore, the filter cutoff frequency is more consistent with the actual speed characteristics of the drive motor, and the filter cutoff frequency can be adaptively determined under speed fluctuations, thereby optimizing the filtering accuracy and filtering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0040] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without inventive work, including:

[0041] Figure 1 is a flow chart of a method for determining a filter cutoff frequency provided by an embodiment of the present disclosure;

[0042] Figure 2 is a flow chart of a drive motor control method provided by an embodiment of the present disclosure;

[0043] Figure 3 is a structural diagram of a device for determining a filter cutoff frequency provided by an embodiment of the present disclosure;

[0044] Figure 4Schematic diagram of the structure of the motor controller provided by the embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] The following describes embodiments of the present disclosure in more detail with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of protection of the present disclosure.

[0046] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in this disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0047] It should be noted that the modifications of "one" and "multiple" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more".

[0048] In order to solve the problem that the existing solution cannot achieve good overall filtering accuracy and filtering effect regardless of whether the phase current frequency corresponding to the maximum speed or the phase current frequency corresponding to the current speed is used to determine the filtering cutoff frequency, the embodiment of the present disclosure provides a new method for determining the filtering cutoff frequency.

[0049] The method for filtering cutoff frequency provided in the embodiment of the present disclosure determines the filtering cutoff frequency according to the target speed characteristics and estimated speed characteristics of the driving motor, so that the filtering cutoff frequency is more in line with the actual situation, thereby improving the filtering accuracy and filtering effect.

[0050] Figure 1 FIG. 1 is a flow chart of a method for determining a filter cutoff frequency according to an embodiment of the present disclosure. Figure 1 As shown, the method for determining the filtering cutoff frequency provided by the embodiment of the present disclosure includes S110-S130.

[0051] In practical applications, since the speed control of the drive motor is implemented by the motor controller, considering the real-time requirements of the motor control, the method for determining the filter cutoff frequency in the embodiment of the present disclosure is executed by the motor controller.

[0052] Of course, the method for determining the filter cutoff frequency is not limited to being executed by the motor controller, but can also be executed by a host computer system (such as a vehicle computer system).

[0053] S110: Calculating a theoretical phase current frequency according to a target rotational speed of the driving motor in a current cycle, and calculating an estimated phase current frequency according to an estimated rotational speed of the driving motor in the current cycle.

[0054] In the embodiment of the present disclosure, the motor controller performs calculations according to the set execution frequency and determines the filter cutoff frequency of the current cycle in real time.

[0055] The target speed for the current cycle is the target speed that the drive motor should ideally achieve in the current cycle. In practical applications, the drive motors that power water pumps and electric compressors often adjust their speed according to a set speed acceleration. After determining the target speed for the drive motor in the previous cycle, the target speed for the drive motor in the current cycle can be calculated based on the speed and speed acceleration of the previous cycle. Specifically, the target speed for the current cycle can be calculated using the following steps S111-S112.

[0056] S111 : Calculate the difference between the requested rotation speed and the target rotation speed in the previous cycle, and determine the rotation speed acceleration based on the difference.

[0057] In a specific embodiment, the speed adjustment method of the driving motor can be a ramp function V set (k)=V set (k-1)+a characterization, where V set (k) represents the target speed of the driving motor in the current cycle, V set (k-1) represents the target speed of the drive motor in the previous cycle, a represents the speed acceleration of the drive motor, and a is related to the characteristic parameters of the electric drive motor itself and the actual control requirements and is predetermined.

[0058] In practical applications, it is necessary to drive the motor according to the required speed V req and the target speed V in the previous cycle set The difference between (k-1) determines the speed acceleration specifically as follows: If V set (k)>V set (k-1), then a predetermined first preset acceleration, which is the acceleration in the same direction as the current cycle target speed; if V set (k) <V set (k-1), then a is a predetermined second preset acceleration, which is an acceleration in the opposite direction to the target speed of the current cycle; and if V set (k)=V set (k-1), then the value of a is 0.

[0059] S112: Calculate the target speed of the current cycle based on the target speed and speed acceleration of the previous cycle.

[0060] According to the aforementioned ramp function formula, after obtaining the target speed of the previous cycle and the rotational acceleration, the target speed of the current cycle can be obtained by adding the two.

[0061] In other embodiments, after determining the current speed and the required speed of the drive motor, the motor controller may determine a speed adjustment time based on the difference between the current speed and the required speed, as well as the speed acceleration of the drive motor. The controller then controls the drive motor to adjust its speed according to the speed acceleration during the speed adjustment time. Accordingly, the target speed for the current cycle may also be determined based on the time difference between the current cycle and the initial cycle, the initial speed of the drive motor, and the aforementioned rotational acceleration.

[0062] After obtaining the target speed of the current cycle, the theoretical phase current frequency can be calculated based on the target speed of the current cycle. curr =V set ·p / 60 calculates the theoretical phase current frequency f curr , V set is the target speed of the current cycle (the unit of this target speed is revolutions per minute), and p is the number of motor pole pairs.

[0063] The estimated speed of the drive motor in the current cycle is estimated using a pre-selected motor speed estimation algorithm (e.g., a position sensorless control algorithm). The specific motor speed estimation algorithm is not detailed here; please refer to relevant technical literature for details.

[0064] After obtaining the estimated speed of the current cycle, the estimated phase current frequency can be calculated based on the estimated speed of the current cycle. Calculate the theoretical phase current frequency is the target speed of the current cycle (the unit of this target speed is revolutions per minute), and p is the number of motor pole pairs mentioned above.

[0065] S120: Calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency.

[0066] In the embodiment of the present disclosure, the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient are calculated based on the theoretical phase current frequency and the estimated phase current frequency, and the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient are estimated according to a specific calculation method.

[0067] In some embodiments, the theoretical frequency weighting coefficient is k1, and the estimated frequency weighting coefficient is Based on the above formula, the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient are calculated based on the theoretical phase current frequency and the estimated phase current frequency as follows S121-S122.

[0068] S121: Calculate the sum of the theoretical phase current frequency and the estimated phase current frequency.

[0069] According to the above formula, the sum of the theoretical phase current frequency and the estimated phase current frequency is

[0070] S122: Determine a theoretical frequency weighting coefficient based on a ratio of a theoretical phase current frequency to a sum value, and determine an estimated frequency weighting coefficient based on a ratio of an estimated phase current frequency to a sum value.

[0071] According to the aforementioned formula, if the theoretical phase current frequency is greater than the estimated phase current frequency, the corresponding theoretical frequency weighting coefficient is also greater, and the estimated frequency weighting coefficient is also smaller. Conversely, if the theoretical phase current frequency is smaller than the estimated phase current frequency, the corresponding theoretical frequency weighting coefficient is also smaller, and the estimated frequency weighting coefficient is also larger. Furthermore, from the aforementioned formula, we can see that k1 + k2 = 1.

[0072] In practical applications, in addition to using the aforementioned method to calculate the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient, other methods may also be used to determine the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient. For example, in some embodiments, after obtaining the theoretical phase current frequency and the estimated phase current frequency, the motor controller first calculates the ratio of the theoretical phase current frequency to the estimated phase current frequency, and then uses the calculated ratio to search a pre-set data table to determine the corresponding theoretical frequency weighting coefficient and the estimated frequency weighting coefficient. In practical applications, the sum of the paired theoretical frequency weighting coefficients and the estimated frequency weighting coefficients stored in the data table may be 1 or may not be 1.

[0073] S130: Perform weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filter cutoff frequency of the current cycle.

[0074] After obtaining the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient, the filter cutoff frequency of the current cycle can be determined by weighted summation. Specifically, the motor controller can use The filter cutoff frequency of the current cycle is calculated, where c is a preset value, which is generally set to 2-5.

[0075] The method for determining the filter cutoff frequency provided by the embodiment of the present disclosure first determines the theoretical phase current frequency and the estimated phase current frequency of the drive motor in the current cycle, then calculates the corresponding theoretical frequency weighting coefficient and the estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency, and obtains the filter cutoff frequency of the current cycle by weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient. The filter cutoff frequency determined based on the above method is essentially determined based on the actual speed of the predicted drive motor. Therefore, the filter cutoff frequency is more consistent with the actual speed characteristics of the drive motor, and the filter cutoff frequency can be adaptively determined under speed fluctuations, thereby optimizing the filtering accuracy and filtering effect.

[0076] In addition to providing the aforementioned method for determining the filter cutoff frequency, an embodiment of the present disclosure also provides a method for controlling a drive motor. Figure 2 This is a flow chart of the driving motor control method provided by the embodiment of the present disclosure. Figure 2 As shown, the driving motor control method provided by the embodiment of the present disclosure includes S210-S260.

[0077] S210: Calculating a theoretical phase current frequency according to a target rotational speed of the driving motor in a current cycle, and calculating an estimated phase current frequency according to an estimated rotational speed of the driving motor in the current cycle.

[0078] S220: Calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency.

[0079] S230: Perform weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filter cutoff frequency of the current cycle.

[0080] The specific implementation process of S210-S230 is the same as the steps of S110-S130 in the previous embodiment, and will not be repeated here. For details, please refer to the previous description.

[0081] S240: Construct a low-pass filter based on the filter cutoff frequency.

[0082] In some embodiments of the present disclosure, the low-pass filter constructed based on the filter medium frequency can be a first-order low-pass filter, which is characterized by U o (k)=U o (k-1) / (1+ω c T)+ω c T.U i (k) / (1+ω c T), where ω c =2πf cutoffIt can be imagined that, using the embodiment of the present disclosure, the low-pass filter is based on the output U of the filter obtained in the previous cycle. o (k-1) and the input U of the current cycle filter i (k) Determine the output U of the low-pass filter o (k).

[0083] Of course, the low-pass filter constructed based on the filtering cutoff frequency in the embodiment of the present disclosure is not limited to the aforementioned first-order low-pass filter, but can also be a high-order low-pass filter.

[0084] S250: Determine the motor flux or the motor back electromotive force of the drive motor.

[0085] Based on motor principles, the motor controller can detect the flux linkage using a magnetic flux sensor installed in the motor, or measure the voltage using a voltmeter installed in the circuit, and use a pre-set calculation method to determine the motor flux linkage or motor back electromotive force (EMF) that drives the motor. As you can imagine, the magnitude of the motor flux linkage and motor back electromotive force is positively correlated with the motor's speed.

[0086] In a specific implementation, the motor controller may use a sliding mode observer method, a nonlinear flux observer method, or a virtual coordinate axis method to determine the motor flux or the motor back electromotive force of the drive motor.

[0087] S260: low-pass filtering the motor flux or the motor back electromotive force using a low-pass filter to obtain filtered flux or filtered back electromotive force.

[0088] According to the aforementioned first-order low-pass filter form, a low-pass filter is used to low-pass filter the motor magnetism or motor back EMF to obtain a filtered flux or filtered back EMF. The motor flux or motor back EMF predicted in the current cycle is input into the low-pass filter, and the input motor flux or motor back EMF is processed using a first weighting coefficient determined based on the filter cutoff frequency to obtain first weighted data. The first weighted data is then added to the second weighted data to obtain the filtered flux or filtered back EMF. The second weighted data is determined by multiplying the motor flux or motor back EMF output in the previous cycle by a second weighting coefficient determined based on the filter frequency.

[0089] S270: Determine the rotor position of the drive motor according to the filtered magnetic flux or the filtered back electromotive force.

[0090] After determining the filtered flux or filtered back electromotive force, the rotor position of the drive motor is estimated based on the motor model. In a specific implementation, the position of the drive motor rotor can be estimated using a flux / back electromotive force estimation method based on the motor fundamental frequency model.

[0091] After determining the rotor position of the drive motor using the above method, the real-time rotation speed of the rotor can be estimated based on the position of the rotor in the adjacent cycle, and the speed of the drive motor can be determined to meet the required speed based on the real-time speed, thereby determining how to control the motor rotation in the future.

[0092] The drive motor control method provided in this embodiment can optimize the method for determining the filter cutoff frequency, improve the filtering accuracy, and further optimize the rotor position estimation accuracy and the stability of the overall control.

[0093] In addition to providing the aforementioned method for determining a filter cutoff frequency, the embodiment of the present disclosure further provides an apparatus 300 for determining a filter cutoff frequency. Figure 3 FIG. 3 is a schematic diagram of the structure of the device 300 for determining the filter cutoff frequency provided by an embodiment of the present disclosure. Figure 3 As shown, the device 300 for determining the filter cutoff frequency includes a frequency calculation unit 301 , a weighting coefficient calculation unit 302 and a cutoff frequency determination unit 303 .

[0094] The frequency calculation unit 301 is used to calculate the theoretical phase current frequency according to the target rotation speed of the driving motor in the current cycle, and to calculate the estimated phase current frequency according to the estimated rotation speed of the driving motor in the current cycle.

[0095] The weighting coefficient calculation unit 302 is used to calculate a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency.

[0096] The cutoff frequency determination unit 303 is configured to perform weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filtering cutoff frequency.

[0097] In some embodiments, before the frequency calculation unit 301 calculates the theoretical phase current frequency according to the target speed of the drive motor in the current cycle, the frequency calculation unit 301 further calculates the target speed of the current cycle according to the requested speed and the target speed of the previous cycle.

[0098] In some embodiments, the frequency calculation unit 301 first calculates the difference between the requested speed and the target speed in the previous cycle, and determines the speed acceleration based on the difference; then calculates the target speed of the current cycle based on the target speed and speed acceleration in the previous cycle.

[0099] In some embodiments, when the difference is greater than 0, the frequency calculation unit 301 uses the first preset acceleration in the same direction as the target speed in the previous cycle as the speed acceleration; when the difference is less than 0, the frequency calculation unit 301 uses the second preset acceleration in the opposite direction to the target speed in the previous cycle as the speed acceleration; when the difference is 0, the frequency calculation unit 301 determines that the speed acceleration is 0; the magnitudes of the first preset acceleration and the second preset acceleration are pre-set.

[0100] In some embodiments, the weighting coefficient calculation unit 302 first calculates the sum of the theoretical phase current frequency and the estimated phase current frequency, and then determines the theoretical frequency weighting coefficient based on the ratio of the theoretical phase current frequency and the sum, and determines the estimated frequency weighting coefficient based on the ratio of the estimated phase current frequency and the sum.

[0101] In some embodiments, the cut-off frequency determination unit 303 adopts Get the cutoff frequency f cutoff , where c is a value greater than 1, k1 is the theoretical frequency weighting coefficient, f curr is the theoretical phase current frequency, k2 is the estimated frequency weighting coefficient, To estimate the phase current frequency.

[0102] The present disclosure also provides a drive motor control device. The drive motor control device includes an electromagnetic characteristic determination unit, a filter determination unit, a filter unit, and a rotor position determination unit. The electromagnetic characteristic determination unit is used to obtain the motor flux or motor back electromotive force of the drive motor.

[0103] The filter determination unit is used to determine the filter cutoff frequency by adopting the above-mentioned filter cutoff frequency determination method, and construct a low-pass filter based on the filter cutoff frequency;

[0104] The filtering unit is used to perform low-pass filtering on the motor flux or the motor back electromotive force using a low-pass filter to obtain filtered flux or filtered back electromotive force;

[0105] The rotor position determination unit is used to determine the rotor position of the drive motor according to the filtered flux or the filtered back electromotive force.

[0106] The embodiment of the present disclosure also provides a motor controller for implementing the aforementioned method. Figure 4 This is a schematic diagram of the structure of the motor controller provided by the embodiment of the present disclosure. Figure 4 , which shows a structural diagram of a motor controller 400 suitable for implementing the embodiment of the present disclosure. Figure 4 The motor controller shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0107] like Figure 4 As shown, the motor controller 400 may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory ROM 402 or a program loaded from a storage device 408 into a random access memory RAM 403. Various programs and data required for the operation of the motor controller 400 are also stored in the RAM 403. The processing device 401, the ROM 402, and the RAM 403 are connected to each other via a bus 404. An input / output I / O interface 405 is also connected to the bus 404.

[0108] Typically, the following devices may be connected to the I / O interface 405: an input device 405 including, for example, a touch screen, a touchpad, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 407 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 408 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 409. The communication device 409 may allow the motor controller 400 to communicate with other devices wirelessly or by wire to exchange data. Although Figure 4 The motor controller 400 is shown with various devices, but it should be understood that it is not required to implement or have all of the devices shown. More or fewer devices may be implemented or have instead.

[0109] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a non-transitory computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication device 409, or installed from the storage device 408, or installed from the ROM 402. When the computer program is executed by the processing device 401, the above-mentioned functions defined in the method of the embodiment of the present disclosure are performed.

[0110] It should be noted that the computer-readable medium mentioned above in the present disclosure may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device, or component. In the present disclosure, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof.

[0111] In some embodiments, the client and server can communicate using any currently known or future developed network protocol, such as HTTP (HyperText Transfer Protocol), and can be interconnected with any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network ("LAN"), a wide area network ("WAN"), an internet (e.g., the Internet), and a peer-to-peer network (e.g., an ad hoc peer-to-peer network), as well as any currently known or future developed network.

[0112] The computer-readable medium may be included in the motor controller, or it may exist independently and not be incorporated into the motor controller. The computer-readable medium carries one or more programs that, when executed by the motor controller, cause the motor controller to: calculate a theoretical phase current frequency based on the target speed of the drive motor in the current cycle, and calculate an estimated phase current frequency based on the estimated speed of the drive motor in the current cycle; calculate a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency; and perform a weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filter cutoff frequency for the current cycle.

[0113] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including, but not limited to, object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the tester computer, partially on the tester computer, as a stand-alone software package, partially on the tester computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the tester computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0114] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0115] The units involved in the embodiments described in this disclosure may be implemented in software or hardware, wherein the name of a unit does not necessarily limit the unit itself.

[0116] The functions described above herein may be performed, at least in part, by one or more hardware logic components. For example, and without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chip (SOCs), complex programmable logic devices (CPLDs), and the like.

[0117] In the context of the present disclosure, a machine-readable medium can be a tangible medium that can contain or store a program for use by or in conjunction with an instruction execution system, device or equipment. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium can include an electrical connection according to one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0118] The embodiment of the present disclosure also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it can implement the method of any of the above method embodiments. Its execution method and beneficial effects are similar and will not be repeated here.

[0119] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0120] The foregoing are merely specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not to be limited to the embodiments described herein, but is to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining a filter cutoff frequency, characterized in that: include: Calculating a theoretical phase current frequency according to a target rotational speed of the drive motor in a current cycle, and calculating an estimated phase current frequency according to an estimated rotational speed of the drive motor in the current cycle; Calculating a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency; A weighted sum is performed based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain a filter cutoff frequency of the current cycle.

2. The method according to claim 1, characterized in that Before calculating the theoretical phase current frequency according to the target speed of the drive motor in the current cycle, the method further includes: The target speed of the current cycle is calculated based on the requested speed and the target speed of the previous cycle.

3. The method according to claim 2, characterized in that Calculating the target speed of the current cycle based on the requested speed and the target speed of the previous cycle includes: calculating a difference between the requested speed and a target speed in a previous cycle, and determining a speed acceleration based on the difference; The target speed of the current cycle is calculated based on the target speed of the previous cycle and the speed acceleration.

4. The method according to claim 3, characterized in that Determining the rotational speed acceleration based on the difference includes: When the difference is greater than 0, a first preset acceleration having the same direction as the target speed in the previous cycle is used as the speed acceleration; When the difference is less than 0, a second preset acceleration in a direction opposite to the target speed in the previous cycle is used as the speed acceleration; When the difference is 0, determining the rotational speed acceleration to be 0; The magnitudes of the first preset acceleration and the second preset acceleration are preset.

5. The method according to any one of claims 1 to 4, characterized in that The calculating of the theoretical frequency weighting coefficient and the estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency includes: Obtaining a sum of the theoretical phase current frequency and the estimated phase current frequency; The theoretical frequency weighting coefficient is determined based on a ratio of the theoretical phase current frequency to the sum value, and the estimated frequency weighting coefficient is determined based on a ratio of the estimated phase current frequency to the sum value.

6. The method according to claim 5, characterized in that The step of performing weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient to obtain the cutoff frequency includes: use Get the cutoff frequency f cutoff , where c is a value greater than 1, k1 is the theoretical frequency weighting coefficient, f curr is the theoretical phase current frequency, k2 is the estimated frequency weighting coefficient, is the estimated phase current frequency.

7. A driving motor control method, characterized in that: include: Obtain the motor flux or motor back electromotive force of the drive motor; Determine a filter cutoff frequency using the method according to any one of claims 1 to 6, and construct a low-pass filter based on the filter cutoff frequency; Using the low-pass filter to perform low-pass filtering on the motor flux or the motor back electromotive force to obtain filtered flux or filtered back electromotive force; The rotor position of the drive motor is determined according to the filtered flux or the filtered back electromotive force.

8. A device for determining a filter cutoff frequency, characterized in that: include: a frequency calculation unit, configured to calculate a theoretical phase current frequency according to a target rotational speed of the drive motor in a current cycle, and to calculate an estimated phase current frequency according to an estimated rotational speed of the drive motor in the current cycle; a weighting coefficient calculation unit, configured to calculate a theoretical frequency weighting coefficient and an estimated frequency weighting coefficient based on the theoretical phase current frequency and the estimated phase current frequency; The cutoff frequency determining unit is configured to obtain a filtering cutoff frequency by performing weighted summation based on the theoretical phase current frequency, the estimated phase current frequency, the theoretical frequency weighting coefficient, and the estimated frequency weighting coefficient.

9. A drive motor control device, characterized in that: include: An electromagnetic characteristic determination unit, used to obtain the motor flux or motor back electromotive force of the drive motor; a filter determination unit, configured to determine a filter cutoff frequency using the method according to any one of claims 1 to 6, and construct a low-pass filter based on the filter cutoff frequency; a filtering unit, configured to perform low-pass filtering on the motor flux or the motor back electromotive force using the low-pass filter to obtain a filtered flux or a filtered back electromotive force; A rotor position determining unit is configured to determine the rotor position of the drive motor according to the filtered flux or the filtered back electromotive force.

10. A motor controller, characterized in that: comprising a processor and a memory, said memory being configured to store a computer program; When the computer program is loaded by the processor, the processor is caused to execute the method according to any one of claims 1 to 7.

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