Single resistor sampling current reconstruction method, device, permanent magnet synchronous motor and medium

Abstract

The present application provides a single-resistor sampling current reconstruction method, device, permanent magnet synchronous motor and medium, the method comprising: calculating the size of the current sampling interval of the two phases that can be currently sampled by the three-phase motor based on the voltage vector sector at the current moment, respectively, to obtain a first sampling interval and a second sampling interval; when one of the first sampling interval and the second sampling interval is less than the minimum sampling interval, using a single resistor to sample the corresponding phase current value of the sampling interval that is not less than the minimum sampling interval at the current moment; and reconstructing the current values ​​of the other two phases in the three-phase motor at the current moment based on the corresponding phase current value and electrical angle at the current moment, and the phase current amplitude and current deflection angle at the previous moment. The single-resistor sampling method based on the present application is compatible with current prediction methods of different control strategies.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a single-resistor sampling current reconstruction method, device, permanent magnet synchronous motor and medium. Background Art

[0002] In the prior art, a current sampling interval is generally reserved by means of pulse width modulation (PWM) left-right shifting, and two phase currents are sampled at different sampling moments within a carrier cycle, and then the third phase current is reconstructed by the relationship that the sum of the three-phase current vectors is zero. However, it is inevitable that when the motor is running at high speed, there are situations where the duty cycles of the two phases are large and close to the full duty cycle. At this time, it is impossible to reserve sufficient sampling intervals by means of PWM left-right shifting, and only one phase current can be sampled within a carrier cycle. In order to avoid the situation where the duty cycles of the two phases are large and close to the full duty cycle, resulting in the inability to reserve sufficient sampling space by means of PWM left-right shifting, the existing solution is to limit the duty cycle size or use other methods to predict the phase current that cannot be obtained by sampling. Summary of the Invention

[0003] In view of the above problems, the present application proposes a single-resistor sampling current reconstruction method, device, permanent magnet synchronous motor and medium.

[0004] The present application provides a method for reconstructing a current sampled by a single resistor. A single resistor is provided on the DC bus of a three-phase motor. The method includes:

[0005] According to the voltage vector sector at the current moment, the sizes of the current sampling intervals of the two phases of the three-phase motor that can be collected at the current moment are calculated respectively to obtain a first sampling interval and a second sampling interval;

[0006] When one of the first sampling interval and the second sampling interval is smaller than the minimum sampling interval, a corresponding phase current value of the sampling interval that is not smaller than the minimum sampling interval at the current moment is collected through a single resistor;

[0007] The current values ​​of the other two phases in the three-phase motor at the current moment are reconstructed based on the corresponding phase current value and electrical angle at the current moment and the phase current amplitude and current deflection angle at the previous moment.

[0008] Furthermore, in the above-mentioned single-resistance sampling current reconstruction method, the current values ​​of the other two phases at the current moment are reconstructed based on the current value and electrical angle of one phase collected at the current moment, and the phase current amplitude and current deflection at the previous moment:

[0009] Reconstruct any one of the other two phases based on the reconstruction formula of the single-phase current value composed of the single-phase current value and electrical angle collected at the current moment, the phase current amplitude and current deviation angle at the previous moment, and then substitute the collected single-phase current value and the reconstructed single-phase current value into the formula whose three-phase current vector sum is zero to reconstruct the third-phase current value.

[0010] Furthermore, in the above single resistor sampling current reconstruction method, it also includes:

[0011] After the current value is reconstructed, the d-axis current and q-axis current are calculated based on the current values ​​of each phase and the electrical angle at the current moment, and the d-axis current and q-axis current are used to update the phase current amplitude and current deflection angle at the current moment.

[0012] Furthermore, in the above-mentioned single resistor sampling current reconstruction method, the update formula is:

[0013]

[0014]

[0015] where i q(k) is the q-axis current at the current moment, i d(k) is the d-axis current at the current moment, i ak 、i bk and i ck is the phase current at the current moment, θ e is the electrical angle at the current moment.

[0016] Furthermore, in the above-mentioned single-resistor sampling current reconstruction method, the phase current amplitude and the current deflection angle are calculated according to the d-axis current and the q-axis current at the corresponding moment according to their respective corresponding formulas.

[0017] Furthermore, in the above-mentioned single resistor sampling current reconstruction method, the calculation formulas for the phase current amplitude and current deflection angle are respectively:

[0018]

[0019]

[0020] Among them I s(k-1) is the phase current amplitude at the previous moment, i d(k-1) is the d-axis current at the previous moment, i q(k-1) is the q-axis current at the previous moment, Δθ (k-1) is the current deflection angle at the previous moment.

[0021] Furthermore, in the above-mentioned single resistor sampling current reconstruction method, the reconstruction formula of each phase current value is:

[0022] iak =-sin(θ e -Δθ (k-1) )*I s(k-1) ;

[0023]

[0024]

[0025] where i ak 、i bk and i ck is the phase current at the current moment, θ e is the current electrical angle, Δθ (k-1) is the current deflection angle at the previous moment, I s(k-1) is the phase current amplitude at the previous moment.

[0026] Another embodiment of the present application provides a device for reconstructing current by sampling with a single resistor, the device comprising:

[0027] a calculation unit, configured to calculate the sizes of current sampling intervals of two phases of the three-phase motor that can be collected at the current moment according to the voltage vector sector at the current moment, to obtain a first sampling interval and a second sampling interval;

[0028] A collection unit, configured to collect, through a single resistor, a phase current value corresponding to a sampling interval that is not less than the minimum sampling interval at a current moment when one of the first sampling interval and the second sampling interval is less than the minimum sampling interval;

[0029] The reconstruction unit is used to reconstruct the current values ​​of the other two phases in the three-phase motor at the current moment based on the corresponding phase current value and electrical angle at the current moment and the phase current amplitude and current deflection angle at the previous moment.

[0030] Another embodiment of the present application proposes a permanent magnet synchronous motor, including a storage unit and a processing unit. The storage unit stores a computer program, and the processing unit executes the steps of the above-mentioned single-resistance sampling current reconstruction method by calling the computer program stored in the storage unit.

[0031] Another embodiment of the present application provides a computer-readable storage medium storing a computer program. The computer program is suitable for being loaded by a processor to execute the steps of the above single-resistor sampling current reconstruction method.

[0032] The embodiments of the present application have the following beneficial effects:

[0033] The present invention proposes a single-resistor sampling current reconstruction method. Since the method does not restrict the d-axis current in the control strategy, it is applicable to control strategies including field weakening control, maximum torque per ampere (MTPA) control, and d-axis current zero control. This method has strong compatibility and improves the accuracy of the algorithm, allowing for greater promotion of the single-resistor sampling solution. Furthermore, compared to dual-resistor sampling and triple-resistor sampling, single-resistor sampling only requires one sampling resistor, offering significant cost advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of this application and should not be regarded as limiting the scope of protection of this application. In each of the drawings, similar components are numbered similarly.

[0035] Figure 1 A schematic diagram showing the structure of a system for a method for reconstructing a single-resistor current sampling according to some embodiments of the present application is shown;

[0036] Figure 2 A first flow chart showing a method for reconstructing a single resistor sampling current according to some embodiments of the present application is shown;

[0037] Figure 3 A first table showing a method for reconstructing a single-resistor sampling current according to some embodiments of the present application;

[0038] Figure 4 A second table showing a method for reconstructing a single-resistor sampling current according to some embodiments of the present application;

[0039] Figure 5 A duty cycle diagram illustrating a method for reconstructing a current using a single resistor sampling circuit according to some embodiments of the present application is shown;

[0040] Figure 6 A second flow chart showing a method for reconstructing a single-resistor sampling current according to some embodiments of the present application is shown;

[0041] Figure 7 A device structure diagram of a method for single-resistor current sampling reconstruction according to some embodiments of the present application is shown. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0043] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0044] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present application, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0045] Furthermore, the terms “first,” “second,” “third,” etc., are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0046] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0047] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0048] Generally, three-phase permanent magnet synchronous motors (PMSMs) can be divided into two types: interior permanent magnet synchronous motors (IPMSMs) and surface permanent magnet synchronous motors (SPMSMs), depending on the structure of their permanent magnet rotors. The SPMSM achieves maximum motor efficiency when the d-axis current is equal to zero. The IPMSM, on the other hand, generally adopts a maximum torque current ratio control strategy, which achieves optimal control efficiency when the d-axis current is non-zero. The MTPA control strategy can be simply described as follows: the current ratio refers to the d-axis current (id) divided by the q-axis current (iq), where the q-axis current and the d-axis current are the quadrature-axis component and direct-axis component of the stator current, respectively. When the stator current is constant, this ratio is adjusted to achieve maximum torque, achieving optimal motor efficiency. At this point, id is non-zero, and the stronger the motor's salient polarity, the greater the id. Regardless of whether it is SPMSM or IPMSM, in some situations where the motor speed needs to be increased, some motor efficiency will be sacrificed to obtain the speed increase, that is, weak magnetic control. At this time, id is not 0 and becomes larger as the speed increases.

[0049] Since the limited duty cycle in the existing scheme will limit the maximum speed of the motor, and the existing prediction method is not compatible with multiple motor control strategies, it is necessary to propose a current prediction method that is compatible with different control strategies to further promote the single resistor sampling scheme.

[0050] Currently, the sampling current reconstruction methods usually include single resistor sampling and multi-resistor sampling methods, and this application uses the single resistor sampling method for reconstruction. Figure 1 As shown, the system includes switches S1, S2, S3, S4, S5, S6, a motor M, and a sampling resistor Rs. The sampling resistor Rs is a single resistor in this embodiment. Switches S1 to S6 are simplified as logic switches. Optionally, the switches may include, but are not limited to, field-effect transistors. During operation, switches in the same bridge arm cannot be turned on simultaneously. For example, switches S1 and S4 cannot be turned on simultaneously, switches S2 and S5 cannot be turned on simultaneously, and switches S3 and S6 cannot be turned on simultaneously.

[0051] Based on the above structure, please refer to Figure 2 , which is a flow chart of a method for reconstructing current using a single resistor sampling current, as proposed in an embodiment of the present application. This method can be applied, but is not limited to, to permanent magnet synchronous motors, such as embedded permanent magnet synchronous motors and surface-mount permanent magnet synchronous motors.

[0052] For example, Figure 2As shown, the single resistor sampling current reconstruction method includes:

[0053] S101 , calculating the sizes of current sampling intervals of two phases of a three-phase motor that can be collected at the current moment according to the voltage vector sector at the current moment, to obtain a first sampling interval and a second sampling interval.

[0054] Combine Figure 1 , according to the opening and closing of these six switches, a variety of bus currents can be combined, where the bus current is the current flowing through the sampling resistor Rs. Assuming that 1 represents on and 0 represents off, when the logic of the control switch is S1S2S3=100, it means that switch S1 is on, switch S2 is off, and switch S3 is off, and the corresponding on-off status of the lower switch is opposite to that of the upper switch, that is, switch S4 is off, switch S5 is on, and switch S6 is on. Finally, the current flowing through the sampling resistor Rs is exactly the positive a-phase current ia, where the positive and negative of the current is determined by the current direction, the current flowing to the motor M is positive, and the current flowing out of the motor M is negative. Based on the above principle, the correspondence table between the control logic of the switch and the sampling phase current can be derived, such as Figure 3 shown.

[0055] Furthermore, if Figure 4 As shown, the current three-phase duty cycle can be obtained according to the current vector sector, thereby obtaining the two-phase current that can be collected. Then, based on the current control logic and duty cycle, the sampling interval of the two-phase current that can be collected can be calculated. Figure 5 As shown, when the control logic is S1S2S3=100, the first sampling interval D1 can be obtained, and when the control logic is S1S2S3=110, the second sampling interval D2 can be obtained. The first sampling interval and the second sampling interval can be calculated by the following formula:

[0056]

[0057] Tmax, Tmid, and Tmin are the maximum, median, and minimum duty cycles of the three-phase duty cycles, respectively, and are determined by the sector the current voltage vector is in. PWM_MAX is the maximum count value in center-aligned counting mode.

[0058] Furthermore, due to the difference between reality and ideal conditions, the instantaneous switching of the switching device during the actual sampling process will cause overshoot and ringing of the bus current. Therefore, it is necessary to delay sampling for a period of time, otherwise the sampled current will be incorrect. Therefore, in order to reduce the error, it is necessary to measure the minimum sampling interval Dmin to avoid it accordingly. Figure 5 As shown in FIG, Idc_ideal is the bus current under ideal conditions, and Idc_real is the bus current under actual conditions.

[0059] S201 : When one of the first sampling interval and the second sampling interval is smaller than the minimum sampling interval, a corresponding phase current value of the sampling interval that is not smaller than the minimum sampling interval at the current moment is collected through a single resistor.

[0060] Specifically, the first sampling interval and the second sampling interval are respectively compared with the minimum sampling interval. If there is a sampling interval smaller than the minimum sampling interval, the single-phase current value of the sampling interval that is not smaller than the minimum sampling interval at the current moment is collected.

[0061] S301 , reconstructing the current values ​​of the other two phases in the three-phase motor at the current moment based on the corresponding phase current value and electrical angle at the current moment, and the phase current amplitude and current deflection angle at the previous moment.

[0062] Optionally, if both the first sampling interval and the second sampling interval are greater than the minimum sampling interval, the current two-phase current is directly collected, and the collected two-phase current is substituted into the three-phase current vector sum zero formula: a +i b +i c =0 and calculate the third phase current value.

[0063] In one embodiment, reconstructing the current values ​​of the other two phases at the current moment based on the current value and electrical angle of one phase collected at the current moment and the phase current amplitude and current deflection angle at the previous moment includes:

[0064] Reconstruct any one of the other two phases based on the reconstruction formula of the single-phase current value composed of the single-phase current value and electrical angle collected at the current moment, the phase current amplitude and current deviation angle at the previous moment, and then substitute the collected single-phase current value and the reconstructed single-phase current value into the formula whose three-phase current vector sum is zero to reconstruct the third-phase current value.

[0065] Specifically, assuming the motor has three phases a, b, and c, the current collected at the current moment is called phase a current. Use the reconstruction formula of the single-phase current value to reconstruct phase b or phase c, and then substitute the phase a current value and the reconstructed phase b or phase c current value into the formula for the sum of the three-phase current vector to be zero to calculate the unknown current value of the last phase. The formula for the sum of the three-phase current vector to be zero is: a +i b +i c =0.

[0066] The above-mentioned phase current amplitude and current deflection angle are calculated according to their respective formulas based on the d-axis current and q-axis current at the corresponding moment. Specifically, the phase current amplitude at the previous moment is calculated according to the phase current amplitude formula, where the phase current amplitude formula is composed of the d-axis value and the q-axis value at the previous moment and some mathematical operations. The phase current deflection angle at the previous moment is calculated according to the phase current deflection angle formula, where the phase current deflection angle formula is composed of the d-axis value and the q-axis value at the previous moment and some mathematical operations.

[0067] Exemplarily, in the above-mentioned single resistor sampling current reconstruction method, the calculation formulas for the phase current amplitude and the current deflection angle are respectively:

[0068]

[0069]

[0070] Among them I s(k-1) is the phase current amplitude at the previous moment, i d(k-1) is the d-axis current at the previous moment, i q(k-1) is the q-axis current at the previous moment, Δθ (k-1) is the current deflection angle at the previous moment.

[0071] In one embodiment, the reconstruction formula of the single-phase current value is:

[0072] i ak =-sin(θ e -Δθ (k-1) )*I s(k-1) ;

[0073]

[0074]

[0075] where i ak 、i bk and i ck is the phase current at the current moment, θ e is the current electrical angle, Δθ (k-1) is the current deflection angle at the previous moment, I s(k-1) is the phase current amplitude at the previous moment.

[0076] Specifically, if the detected current is phase a current, i a As the first phase current value, you can arbitrarily choose the b phase or c phase current corresponding formula to calculate the second phase current value. If the b phase current is selected as the second phase current, then use To calculate the second phase current value, then i a and i bSubstitute into formula i a +i b +i c =0 to calculate i c If the c-phase current is selected as the second-phase current, use To calculate the second phase current value, then i a and i c Substitute into formula i a +i b +i c =0 to calculate i b .

[0077] At this point, the current value of each phase at the current moment can be obtained. At the next moment, the above single resistor sampling current reconstruction method is repeated.

[0078] In yet another embodiment, Figure 6 As shown, after reconstructing the current values ​​of the other two phases, the single resistor sampling current reconstruction method further includes:

[0079] S401 , calculating the d-axis current and the q-axis current based on the current values ​​of the phase currents and the current electrical angle, and updating the current phase current amplitude and current deflection angle using the d-axis current and the q-axis current.

[0080] Specifically, there are three-phase currents in a three-phase motor. In order to achieve the decoupling of the d-axis and the q-axis, the magnetic field and torque characteristics of the motor rotation are separated, and the control system processor is convenient for calculation, thereby obtaining good control characteristics. Generally, the three-phase control is changed to two-phase control, and the current is divided into excitation current and torque current. Among them, the excitation current is used for the excitation coil of the motor to generate an electromagnetic field; the torque current is used on the rotor to enable the rotor to rotate under the action of the electromagnetic field and drag the load. The d-axis current can be regarded as the excitation current, and the q-axis current can be regarded as the torque current. Generally, after the three-phase current is reconstructed, the three-phase current needs to be Clarke transformed to obtain i α and i β , then i α and i β After Park transformation, we get i q and i d The specific process of converting three-phase current into two-phase current can be referred to the existing technology.

[0081] Furthermore, in the above-mentioned single resistor sampling current reconstruction method, the update formula is:

[0082]

[0083]

[0084] where i q(k)is the q-axis current at the current moment, i d(k) is the d-axis current at the current moment, i ak 、i bk and i ck is the phase current at the current moment, θ e is the electrical angle at the current moment.

[0085] Specifically, after the three-phase current at the current moment has been reconstructed, the formula is used to calculate the current i d and i q For example, the current reconstructed three-phase current is i a 、i b and i c , the current electrical angle is θ e , then the updated i d and i q They are:

[0086]

[0087]

[0088] The single-resistor sampling current reconstruction method of this embodiment reconstructs the three-phase current by sampling a single resistor. The method in this application does not restrict the d-axis current in the control strategy, so the applicable control strategy range includes weak magnetic control, maximum torque current ratio control, and d-axis current zero control, etc. It has strong compatibility and improves the accuracy of the algorithm, making the single-resistor sampling solution more popular. In addition, compared with dual-resistor sampling and three-resistor sampling, single-resistor sampling only requires one sampling resistor, which has a great cost advantage.

[0089] Please refer to Figure 7 Another embodiment of the present application provides a device 500 for reconstructing a current sampled by a single resistor, the device comprising:

[0090] The calculation unit 501 is used to calculate the sizes of the current sampling intervals of the two phases of the three-phase motor that can be collected at the current moment according to the voltage vector sector at the current moment, and obtain the first sampling interval and the second sampling interval.

[0091] The collecting unit 502 is configured to collect a single-phase current value of a sampling interval that is not less than the minimum sampling interval at a current moment when one of the first sampling interval and the second sampling interval is less than the minimum sampling interval.

[0092] The reconstruction unit 503 is configured to reconstruct the current values ​​of the other two phases at the current moment based on the current value and electrical angle of one phase collected at the current moment, and the phase current amplitude and current deflection angle at the previous moment.

[0093] It can be understood that the method steps of this embodiment correspond to the single resistor sampling current reconstruction method in the above embodiment, wherein the options of the above single resistor sampling current reconstruction method are also applicable to this embodiment and will not be repeated here.

[0094] Another embodiment of the present application proposes a permanent magnet synchronous motor, including a storage unit and a processing unit. The storage unit stores a computer program, and the processing unit executes the steps of the above-mentioned single-resistance sampling current reconstruction method by calling the computer program stored in the storage unit.

[0095] Another embodiment of the present application provides a computer-readable storage medium storing a computer program. The computer program is suitable for being loaded by a processor to execute the steps of the above single-resistor sampling current reconstruction method.

[0096] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes 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 structure diagram and / or flowchart, and the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0097] In addition, the functional modules or units in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0098] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0099] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A single resistor sampling current reconstruction method, characterized in that: A single resistor is provided on the DC bus of the three-phase motor; the method comprises: According to the voltage vector sector at the current moment, the sizes of current sampling intervals of two phases of the three-phase motor that can be collected at the current moment are calculated respectively to obtain a first sampling interval and a second sampling interval; When one of the first sampling interval and the second sampling interval is smaller than the minimum sampling interval, collecting the corresponding phase current value of the sampling interval that is not smaller than the minimum sampling interval at the current moment through the single resistor; Reconstructing the current values ​​of the other two phases of the three-phase motor at the current moment based on the corresponding phase current value and electrical angle at the current moment and the phase current amplitude and current deflection angle at the previous moment; The phase current amplitude and current deflection angle are calculated according to the d-axis current and q-axis current at the corresponding moment according to their respective corresponding formulas; The calculation formulas for the phase current amplitude and current deflection angle are: ； ； Where, is the phase current amplitude at the previous moment, is the d-axis current at the previous moment, is the q-axis current at the previous moment, is the current deflection angle at the previous moment; The reconstruction formula of each phase current value is: ； ； ； Where, 、 and is the phase current at the current moment, is the current electrical angle, is the current deflection angle at the previous moment, is the phase current amplitude at the previous moment.

2. The single resistor sampling current reconstruction method according to claim 1, characterized in that: Reconstructing the current values ​​of the other two phases at the current moment based on the current value and electrical angle of one phase collected at the current moment, and the phase current amplitude and current deflection angle at the previous moment includes: Reconstruct any one of the other two phases based on the reconstruction formula of the single-phase current value composed of the single-phase current value and electrical angle collected at the current moment, the phase current amplitude and current deviation angle at the previous moment, and then substitute the collected single-phase current value and the reconstructed single-phase current value into the formula whose three-phase current vector sum is zero to reconstruct the third-phase current value.

3. The single resistor sampling current reconstruction method according to claim 1, characterized in that: Also includes: Based on the current values ​​of each phase and the electrical angle at the current moment, the d-axis current and the q-axis current are calculated, and the phase current amplitude and the current deflection angle at the current moment are updated using the d-axis current and the q-axis current.

4. The single resistor sampling current reconstruction method according to claim 3, characterized in that: The update formula is: ； ； in is the q-axis current at the current moment, is the d-axis current at the current moment, 、 and is the phase current at the current moment, is the electrical angle at the current moment.

5. A device for reconstructing current by sampling with a single resistor, characterized in that: include: a calculation unit, configured to calculate the sizes of current sampling intervals of two phases of the three-phase motor that can be collected at the current moment according to the voltage vector sector at the current moment, to obtain a first sampling interval and a second sampling interval; a collecting unit configured to collect, through the single resistor, a phase current value corresponding to a sampling interval that is not less than the minimum sampling interval at a current moment when one of the first sampling interval and the second sampling interval is less than the minimum sampling interval; a reconstruction unit, configured to reconstruct the current values ​​of the other two phases of the three-phase motor at the current moment based on the corresponding phase current value and electrical angle at the current moment, and the phase current amplitude and current deflection angle at the previous moment; The phase current amplitude and current deflection angle are calculated according to the d-axis current and q-axis current at the corresponding moment according to their respective corresponding formulas; The calculation formulas for the phase current amplitude and current deflection angle are: ； ； in is the phase current amplitude at the previous moment, is the d-axis current at the previous moment, is the q-axis current at the previous moment, is the current deflection angle at the previous moment; The reconstruction formula of each phase current value is: ； ； ； in 、 and is the phase current at the current moment, is the current electrical angle, is the current deflection angle at the previous moment, is the phase current amplitude at the previous moment.

6. A permanent magnet synchronous motor, characterized in that: The method comprises a storage unit and a processing unit, wherein the storage unit stores a computer program, and the processing unit executes the steps of the single-resistor sampling current reconstruction method according to any one of claims 1 to 4 by calling the computer program stored in the storage unit.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the steps of the single-resistor sampling current reconstruction method according to any one of claims 1 to 4.

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