A phase current compensation method and device, a permanent magnet synchronous motor and a storage medium

Abstract

The application relates to the field of motors, in particular to a phase current compensation method and device, a permanent magnet synchronous motor and a storage medium, the method comprising the following steps: acquiring three-phase duty cycles of a permanent magnet synchronous motor; obtaining a sector corresponding to a current sampling compensation point based on the three-phase duty cycles, and calculating a position parameter of the current sampling compensation point in the corresponding sector; obtaining a compensation ratio of a sampling current based on the position parameter in the sector; and compensating a current sampling value based on the compensation ratio. The application overcomes the influence of inaccurate phase current sampling, and can obtain the same good sampling and control effect in a low-cost current sampling scheme.

Description

Technical Field

[0001] This application relates to the field of electric motors, and more particularly to a phase current compensation method, device, permanent magnet synchronous motor, and storage medium. Background Technology

[0002] In order to save on the cost of sampling resistors and corresponding operational amplifier circuits, current sampling for permanent magnet synchronous motors often employs single-resistor or dual-resistor current sampling techniques, using current reconstruction technology to obtain the complete three-phase current. However, the sampling accuracy of such current sampling schemes is easily affected by the coupling of hardware circuits and software sampling window size, making it difficult to obtain accurate three-phase current through simple current reconstruction algorithms. If accurate three-phase current cannot be obtained, the smoothness of motor control is greatly reduced, and significant noise and torque ripple are likely to occur. Summary of the Invention

[0003] In view of the above problems, this application proposes a phase current compensation method, device, permanent magnet synchronous motor and storage medium.

[0004] This application provides a phase current compensation method, including:

[0005] Obtain the three-phase duty cycle of the permanent magnet synchronous motor;

[0006] Based on the three-phase duty cycle, the sector corresponding to the current sampling compensation point is obtained, and the position parameters of the current sampling compensation point in the corresponding sector are calculated.

[0007] Based on the position parameters in the sector, the compensation ratio of the sampling current is obtained;

[0008] The current sampled current value is compensated based on the compensation ratio.

[0009] Furthermore, in the above-described phase current compensation method, obtaining the sector corresponding to the current sampling compensation point based on the three-phase duty cycle includes:

[0010] The sector corresponding to the current sampling compensation point is obtained by querying a preset table based on the three-phase duty cycle relationship. The preset table includes each three-phase duty cycle relationship and the corresponding sector value, with each sector value corresponding to one sector.

[0011] Furthermore, in the above-described phase current compensation method, calculating the position parameters of the current sampling compensation point in the corresponding sector based on the three-phase duty cycle includes:

[0012] Based on the three-phase duty cycle, the position parameters of the current sampling compensation point in the corresponding sector are calculated according to the preset position formula.

[0013] Furthermore, in the above-described phase current compensation method, the preset position formula is:

[0014] P position =(Duty) mid -Duty min ) / (Duty max -Duty min )*n;

[0015] Among them, P position Duty is the location parameter of the current sampling compensation point in the sector. max Duty is the maximum value of the three-phase duty cycle. mid Duty is the median value of the three-phase duty cycle. min is the minimum value of the three-phase duty cycle, and n is the amplification factor.

[0016] Furthermore, in the above-described phase current compensation method, obtaining the compensation ratio of the sampling current based on the position parameters in the sector includes:

[0017] Based on the position parameters in the sector, the preset position compensation ratio curve is queried to obtain the compensation ratio of the sampling current.

[0018] Furthermore, in the above-described phase current compensation method, obtaining the compensation ratio of the sampling current based on the position parameters in the sector includes:

[0019] By fitting the preset position compensation ratio curve, a piecewise function consisting of m line segments is obtained;

[0020] Substituting the position parameters into the piecewise function yields the compensation ratio of the sampling current.

[0021] Furthermore, in the above-described phase current compensation method, the piecewise function is:

[0022]

[0023] Among them, Kcom posive ym is the compensation ratio for the sampling current. posive (P position ) is the function of the m-th line segment, n is the amplification factor, and m is the number of line segments in the fitted piecewise function.

[0024] Another embodiment of this application also proposes a phase current compensation device, comprising:

[0025] The acquisition unit is used to acquire the three-phase duty cycle of the permanent magnet synchronous motor;

[0026] The first lookup unit is used to obtain the sector corresponding to the current sampling compensation point based on the three-phase duty cycle.

[0027] The calculation unit is used to calculate the position of the current sampling compensation point in the corresponding sector based on the three-phase duty cycle;

[0028] The second lookup unit is used to obtain the compensation ratio of the sampling current based on the position in the sector;

[0029] The compensation unit is used to compensate the current sampling current value based on the sampling current compensation ratio.

[0030] Another embodiment of this application also 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 phase current compensation method described above by calling the computer program stored in the storage unit.

[0031] Another embodiment of this application provides a computer-readable storage medium storing a computer program adapted for loading by a processor to perform the steps of the phase current compensation method described above.

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

[0033] This application proposes a phase current compensation method. By obtaining the specific location of the sampling point of the current sampled current within the corresponding sector, a corresponding compensation ratio is obtained through a preset curve. The compensation ratio is used to compensate the sampled current, making it closer to the theoretical value and significantly improving the accuracy of the reconstructed current. In a low-cost current sampling scheme, the same good sampling and control effects can be achieved, not only reducing motor noise but also improving motor operating efficiency and enhancing product performance. This effectively promotes the application of single-resistor and dual-resistor sampling technologies in practical motor control products. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be considered as a limitation on the scope of protection of this application. In the various drawings, similar components are numbered similarly.

[0035] Figure 1 A schematic diagram showing the comparison between the sampled current and the actual current using a traditional single resistor is presented.

[0036] Figure 2 A schematic flowchart of a phase current compensation method according to some embodiments of this application is shown;

[0037] Figure 3 A schematic diagram of a preset table is shown for some embodiments of the phase current compensation method of this application;

[0038] Figure 4 A schematic diagram of the compensation ratio of the sampling current in some embodiments of the phase current compensation method of this application is shown;

[0039] Figure 5 A schematic diagram showing the phase and amplitude relationship of the three phases of the phase current compensation method according to some embodiments of this application is shown;

[0040] Figure 6 A schematic diagram of the three-phase duty cycle and sector of the phase current compensation method according to some embodiments of this application is shown;

[0041] Figure 7 This paper shows a schematic diagram of the sector location curves where the compensation point of the phase current compensation method of some embodiments of this application is located.

[0042] Figure 8 A schematic diagram showing the relationship between the compensation ratio and the location of the compensation point in some embodiments of the phase current compensation method of this application is shown.

[0043] Figure 9 A schematic diagram of line segment fitting is shown for some embodiments of the phase current compensation method of this application;

[0044] Figure 10 A schematic diagram of the sampled current after compensation is shown for some embodiments of the phase current compensation method of this application;

[0045] Figure 11 A structural diagram of a phase current compensation device according to some embodiments of this application is shown. Detailed Implementation

[0046] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0047] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0048] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0049] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0050] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0051] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0052] Typically, such as Figure 1 As shown, the smoother curve represents the true phase A current, which can be acquired using a current clamp and denoted as ia. actual The non-smooth curve represents the A-phase sampled current (uncompensated) obtained using a single-resistor current sampling scheme (all subsequent examples will use single-resistor sampling), denoted as ia. sample The output can be used via the DAC interface to observe it on an oscilloscope. It can be clearly observed that ia... actual with ia sample There is a significant deviation in amplitude, and a "fault" phenomenon appears. (ia) actual with ia sample The amplitude deviation is mainly caused by coupling factors such as hardware circuitry and software sampling window size. The occurrence of the "discontinuity" phenomenon is due to inaccurate current sampling leading to abnormal phase current reconstruction, i.e., a sampling current reconstruction discontinuity. Therefore, current sampling compensation is needed to avoid the occurrence of the "discontinuity" phenomenon.

[0053] Therefore, this application proposes a phase current compensation method to solve the above problems.

[0054] Please refer to Figure 2This is a flowchart of a phase current compensation method proposed in an embodiment of this application. Exemplarily, this phase current compensation method is applied to a permanent magnet synchronous motor.

[0055] The phase current compensation method mentioned above will be explained in detail below.

[0056] In some implementations, such as Figure 2 As shown, a phase current compensation method may include:

[0057] S110, obtain the three-phase duty cycle of the permanent magnet synchronous motor.

[0058] Specifically, the general control algorithm module for permanent magnet synchronous motors can calculate the control setpoint for the three-phase duty cycle.

[0059] S210, based on the three-phase duty cycle, obtain the sector corresponding to the current sampling compensation point.

[0060] Specifically, the entire region within a mechanical cycle is generally divided into 6 sectors. Current sampling methods typically include single-resistor and dual-resistor sampling. When sampling in either method, since the duty cycle of the three phases is different during the sampling process in each sector, the corresponding sector can be inferred based on specific patterns.

[0061] In some implementations of phase current compensation methods, the sector corresponding to the current sampling compensation point is obtained based on the three-phase duty cycle, including:

[0062] The system queries a preset table based on the three-phase duty cycle relationship to obtain the sector corresponding to the current sampling compensation point. The preset table includes each three-phase duty cycle relationship and its corresponding sector value, with each sector value corresponding to one sector.

[0063] Specifically, before implementing this method, a table needs to be created to record the correspondence between each three-phase duty cycle and its corresponding sectors. First, sector numbers need to be manually defined. Since the measured three-phase duty cycles (denoted as Ta, Tb, and Tc) in each sector are Ta>=Tb>Tc, Tb>Ta>=Tc, Tb>=Tc>Ta, Tc>Tb>=Ta, Tc>=Ta>Tb, and Ta>Tc>=Tb, a sector number is added for each relationship to facilitate subsequent operations. The sector value corresponding to Ta>=Tb>Tc is defined as 1, Tb>Ta>=Tc as 2, Tb>=Tc>Ta as 3, Tc>Tb>=Ta as 4, Tc>=Ta>Tb as 5, and Ta>Tc>=Tb as 6. Finally, these relationships are compiled into a pre-defined table, such as... Figure 3As shown. Exemplarily, when Ta>=Tb>Tc, this sector value can be designated as the first sector, numbered 1, where phase a has the largest duty cycle, phase b has the middle duty cycle, and phase c has the smallest duty cycle. Due to the real-time requirements of motor control, the three-phase current needs to be updated within one carrier cycle.

[0064] S310, Based on the three-phase duty cycle, calculate the position parameters of the current sampling compensation point in the corresponding sector.

[0065] Specifically, before discussing compensation, it's important to clarify that regardless of whether it's single-resistor sampling or dual-resistor sampling, it's impossible to simultaneously capture all three-phase currents in certain sectors. Therefore, the currents that cannot be captured will inevitably be reconstructed. According to the single-resistor sampling principle, only phase A and phase C currents can be captured within one carrier cycle. Therefore, it's necessary to use two of the captured phase currents to calculate the remaining phase current, i.e., phase B current is obtained through phase current reconstruction. However, according to the dual-resistor sampling principle, the hardware circuitry determines which two phases (A, B, and C) currents are sampled. For example, if the hardware circuitry is designed to sample phases A and B, then phase C current will be obtained through phase current reconstruction.

[0066] Phase current reconstruction utilizes the principle that the sum of the three-phase currents is zero, i.e., i a +i b +i c =0. In other words, if we know two of the three-phase currents, we can calculate the magnitude of the remaining phase current using the equation. Due to the real-time requirements of motor control, it is necessary to know the three-phase currents of the motor within one carrier cycle, thus requiring the use of this current reconstruction principle. For single-resistor sampling, within one carrier cycle, sampling is triggered by software to collect the corresponding current in the appropriate region, and at most two phase currents can be collected. For dual-resistor sampling, which two phase currents are collected is determined during the hardware circuit design stage, and at most only two phase currents can be collected. Therefore, both of these current sampling methods require current reconstruction of the remaining phase current that cannot be directly sampled.

[0067] Since the reconstructed formulas are theoretically correct, if the sampled current matches the theoretical value, the reconstructed current will also match the theoretical value. The key is how to compensate the sampled current so that the compensated current approaches the theoretical value. Because the three-phase currents differ by only 120 degrees in phase, their amplitude and frequency are essentially the same for a short period. Therefore, the compensation ratio tends to be consistent within the corresponding compensation regions. Based on this, we only need to know the compensation ratio of phase A current in the four sampling regions to know the compensation ratios of the other two phase currents in these four regions, because they are consistent within their respective compensation regions. Therefore, taking phase A current as an example... Figure 4 As shown, in the experiment, the actual value can be measured, and then the theoretical value and the actual value at each moment can be calculated to obtain their ratio, which is used as the compensation ratio. Subsequently, compensation can be made based on the currently acquired sampled current value to restore it as close to the theoretical value as possible, thus eliminating the reconstruction fault phenomenon. Therefore, after obtaining the three-phase duty cycle and calculating which sector the current sampled current belongs to, the exact compensation ratio cannot be determined yet, because there are multiple locations within each sector, and it is also necessary to determine the specific location of the current sampled point within that sector.

[0068] In some implementations, the phase current compensation method calculates the location parameters of the current sampling compensation point in the corresponding sector based on the three-phase duty cycle, including:

[0069] Based on the three-phase duty cycle, the position parameters of the current sampling compensation point in the corresponding sector are calculated according to the preset position formula.

[0070] Specifically, to facilitate the calculation of the exact location of the current sampling point within the corresponding sector, this implementation method requires first calculating a curve showing the location of a current compensation point within the sector. Therefore, as... Figure 5 and Figure 6 As shown, it is necessary to first obtain the relationship diagram of the three-phase duty cycle based on the relationship diagram of the three-phase current phase and amplitude, and then construct a curve of the current compensation point in the sector based on the relationship of the three-phase duty cycle.

[0071] In some implementations, the preset position formula in the phase current compensation method is:

[0072] P position =(Duty) mid -Duty min ) / (Duty max -Duty min )*n;

[0073] Among them, P position Duty is the location parameter of the current sampling compensation point in the sector. maxDuty is the maximum value of the three-phase duty cycle. mid Duty is the median value of the three-phase duty cycle. min is the minimum value of the three-phase duty cycle, and n is the amplification factor.

[0074] Specifically, such as Figure 7 As shown, with the amplification factor n set to 1024, and using the preset position formula, a curve showing the location of the current compensation point within the sector can be obtained. This curve exhibits a triangular wave shape, which can be approximated as a linear change within a specific sector. For example... Figure 7 As shown, in sector "1", the magnification increases from 0 to 1024, representing a positive increase; in sector "6", it decreases from 1024 to 0, representing a negative decrease. In sector "3", the magnification increases from 0 to 1024, representing a positive increase; in sector "4", it decreases from 1024 to 0, representing a negative decrease. The purpose of increasing the magnification factor n is to improve the positional resolution. Of course, n can be set arbitrarily, depending on the specific situation, and is not limited here.

[0075] S410, based on the position parameters in the sector, obtain the sampling current compensation ratio.

[0076] Specifically, after obtaining the exact location of the current sampling current, it is also necessary to obtain the relationship curve between the compensation ratio and the location, so that the corresponding compensation ratio can be found directly based on the specific location.

[0077] In some implementations, the phase current compensation method obtains the sampling current compensation ratio based on the position parameters in the sector, including:

[0078] Based on the position parameters in the sector, the preset position compensation ratio relationship curve is queried to obtain the sampling current compensation ratio.

[0079] Specifically, Figure 4 and Figure 7 By combining these methods, the relationship between the compensation ratio and the sampling point location for each sampling region can be obtained. Taking the first sector as an example, as follows... Figure 8 As shown, the preset position compensation ratio curve of the first sector region can be obtained. Only the current sampling position needs to be calculated, and the corresponding compensation ratio can be obtained according to the preset position compensation ratio curve.

[0080] In some implementations, the phase current compensation method obtains the sampling current compensation ratio based on the position parameters in the sector, including:

[0081] By fitting the preset position compensation ratio curve, a piecewise function consisting of m line segments is obtained.

[0082] Substituting the position parameters into the piecewise function, we obtain the sampling current compensation ratio.

[0083] Specifically, to simplify the calculation, we can also... Figure 8 The relationship curve in the equation is fitted, and the curve is divided into multiple line segments. Here, m is an integer greater than or equal to 3.

[0084] In some implementations, the piecewise function in the phase current compensation method is:

[0085]

[0086] Among them, Kcom posive For the sampling current compensation ratio, ym posive (P position ) is the function of the m-th line segment, n is the amplification factor, and m is the number of line segments in the fitted piecewise function.

[0087] Additionally, it's important to note that when n is divisible by m, the calculation follows the segmented approach described in the formula above. However, when n is not divisible by m, the value of n / m needs to be rounded down. Generally, the rounding symbol is used to indicate taking the smaller value instead of the larger one. For example, [3.6] represents rounding down 3.6 to the nearest integer, resulting in 3, i.e., [3.6] = 3. Then, the starting and ending values ​​of the range for the first (m-1) segments are integer multiples of the rounded value of n / m, i.e., multiples of [n / m]. The range of the last segment is [(m-1)[n / m], n]. The final segmented function is:

[0088]

[0089] As an example, taking the first sector as an example, when m = 3 and n = 1024, the piecewise function is:

[0090]

[0091] Finally, we obtain a line segment function graph showing the compensation ratio of the first sector as a function of position, such as... Figure 9 As shown.

[0092] S510, based on the sampling current compensation ratio, compensate the current sampling current value.

[0093] Specifically, after compensation, taking the A-phase current as an example, the final experimentally measured data is as follows: Figure 10 As shown, the compensated sampling current is close to the theoretical value, and the fault phenomenon completely disappears at this time.

[0094] Because the sampling accuracy of low-cost current sampling methods is easily affected by the coupling of hardware circuits and devices, software sampling window size, etc., it is difficult to obtain accurate three-phase current through simple current reconstruction algorithms. If accurate three-phase current cannot be obtained, the stability of motor control is greatly reduced, easily generating significant noise and torque ripple. Therefore, this embodiment addresses this problem by proposing a corresponding current compensation algorithm, overcoming the influence of inaccurate phase current sampling. It achieves the same good sampling and control effect in a low-cost current sampling scheme, not only reducing motor noise but also improving motor operating efficiency and enhancing product performance. This effectively promotes the application of single-resistor and dual-resistor sampling technologies in practical motor control products.

[0095] Another embodiment of this application also proposes a phase current compensation device 600, such as... Figure 11 As shown, the device 600 includes:

[0096] The acquisition unit 610 is used to acquire the three-phase duty cycle of the permanent magnet synchronous motor.

[0097] The first calculation unit 620 is used to obtain the sector corresponding to the current sampling compensation point based on the three-phase duty cycle.

[0098] The second calculation unit 630 is used to calculate the position of the current sampling compensation point in the corresponding sector based on the three-phase duty cycle.

[0099] The third calculation unit 640 is used to obtain the sampling current compensation ratio based on the position in the sector.

[0100] The compensation unit 650 is used to compensate the current sampled current value based on the sampled current compensation ratio.

[0101] Another embodiment of this application also 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 phase current compensation method described above by calling the computer program stored in the storage unit.

[0102] Another embodiment of this application also proposes a computer-readable storage medium storing a computer program adapted for loading by a processor to perform the steps of the phase current compensation method described above.

[0103] It is understood that the method steps in this embodiment correspond to the phase current compensation method in the above embodiments. The options of the above phase current compensation method are also applicable to this embodiment, and will not be described again here.

[0104] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, in alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0105] In addition, the functional modules or units in the various embodiments of this 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.

[0106] If the aforementioned functions are implemented as software functional 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 this application, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A phase current compensation method, characterized in that, include: Obtain the three-phase duty cycle of the permanent magnet synchronous motor; Based on the three-phase duty cycle, the sector corresponding to the current sampling compensation point is obtained, and the position parameters of the current sampling compensation point in the corresponding sector are calculated according to the preset position formula. Based on the position parameters in the sector, the compensation ratio of the sampling current is obtained; Based on the aforementioned compensation ratio, the current sampled current value is compensated. The preset position formula is as follows: in, The location parameter of the current sampling compensation point in the sector. It is the maximum value of the three-phase duty cycle. This is the median value of the three-phase duty cycle. is the minimum value of the three-phase duty cycle, and n is the amplification factor.

2. The phase current compensation method according to claim 1, characterized in that, The process of obtaining the sector corresponding to the current sampling compensation point based on the three-phase duty cycle includes: The sector corresponding to the current sampling compensation point is obtained by querying a preset table based on the three-phase duty cycle relationship. The preset table includes each three-phase duty cycle relationship and the corresponding sector value, with each sector value corresponding to one sector.

3. The phase current compensation method according to claim 1, characterized in that, The step of obtaining the compensation ratio of the sampling current based on the position parameters in the sector includes: Based on the position parameters in the sector, the preset position compensation ratio curve is queried to obtain the compensation ratio of the sampling current.

4. The phase current compensation method according to claim 1, characterized in that, The step of obtaining the compensation ratio of the sampling current based on the position parameters in the sector includes: By fitting the preset position compensation ratio curve, a piecewise function consisting of m line segments is obtained; Substituting the position parameters into the piecewise function yields the compensation ratio of the sampling current.

5. The phase current compensation method according to claim 4, characterized in that, The piecewise function is: in, This is the compensation ratio for the sampling current. Let n be the function of the m-th line segment, n be the amplification factor, and m be the number of line segments in the fitted piecewise function.

6. A phase current compensation device, characterized in that, include: The acquisition unit is used to acquire the three-phase duty cycle of the permanent magnet synchronous motor; The first lookup unit is used to obtain the sector corresponding to the current sampling compensation point based on the three-phase duty cycle. The calculation unit is used to calculate the position of the current sampling compensation point in the corresponding sector based on the three-phase duty cycle and according to a preset position formula; wherein the preset position formula is: in, The location parameter of the current sampling compensation point in the sector. It is the maximum value of the three-phase duty cycle. This is the median value of the three-phase duty cycle. is the minimum value of the three-phase duty cycle, and n is the amplification factor; The second lookup unit is used to obtain the compensation ratio of the sampling current based on the position in the sector; The compensation unit is used to compensate the current sampling current value based on the sampling current compensation ratio.

7. A permanent magnet synchronous motor, characterized in that, It includes a storage unit and a processing unit. The storage unit stores a computer program, and the processing unit executes the steps of the phase current compensation method as described in any one of claims 1 to 5 by calling the computer program stored in the storage unit.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program adapted for loading by a processor to perform the steps of the phase current compensation method as described in any one of claims 1 to 5.

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