Motor phase current sampling method, device, equipment and storage medium

Abstract

The present invention discloses a motor phase current sampling method, device, equipment and storage medium, wherein the method comprises: obtaining the initial internal resistance value of a power MOS tube, wherein the initial internal resistance value is the internal resistance value determined by the power MOS tube in an initial state; sampling the initial phase current in the initial state according to the initial internal resistance value of the power MOS tube; calculating the first bus current according to the initial phase current; sampling the second bus current through a bus sampling resistor, wherein the second bus current is the bus current in an actual operating state; determining the actual phase current according to the first bus current, the second bus current and the initial phase current. The present invention utilizes the phase current and the bus current determined by the internal resistance value of the power MOS tube in a known state to calculate the phase current corresponding to the detected bus current in the actual operating state, and can determine the accurate phase current without adding a sampling resistor to each phase or adding a temperature sensor for temperature compensation.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a motor phase current sampling method, device, equipment and storage medium. Background Art

[0002] In the field of motor technology, the output current of the three-phase bridge arm drive circuit, that is, the phase current, is usually used to control the operation of the motor. Therefore, the detection sampling results of the phase current will be directly fed back to the control results of the motor. At present, there are usually two solutions for motor phase current sampling. One is to add a sampling resistor to each phase bridge arm; the other is to use the internal resistance of the power MOS tube as the sampling resistor. However, for the first solution, the external resistor method increases the material cost. Due to the large current, the power consumption of the resistor itself will reduce the control efficiency of the controller and increase the difficulty of heat dissipation of the controller. For the second solution, there is a temperature drift problem by sampling the internal resistance of the power MOS tube. Since the internal resistance value of the power MOS tube changes greatly after the temperature rises, it is difficult to accurately calculate the phase current.

[0003] On the other hand, in order to solve the above-mentioned temperature drift problem, the Chinese patent application publication number CN112858755A provides a temperature supplement method, that is, to compensate for the problem caused by temperature drift through temperature, and to estimate the internal resistance value of the power MOS tube according to the typical relationship between temperature and the internal resistance value of the power MOS tube by detecting the temperature. However, due to the delay and loss of heat conduction, the temperature on the PCB board is difficult to timely and accurately reflect the node temperature of the power MOS tube. Therefore, the internal resistance value estimated by this solution is also inaccurate, which leads to errors in the sampled phase current value. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that the method of adding an external sampling resistor in the existing motor phase current sampling scheme will reduce the control efficiency of the controller, while using an internal resistor as the sampling resistor will cause the sampled phase current value to be inaccurate.

[0005] To achieve the above-mentioned purpose, the present invention provides a motor phase current sampling method, comprising: obtaining an initial internal resistance value of a power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state; sampling according to the initial internal resistance value of the power MOS tube to obtain an initial phase current in the initial state; calculating a first bus current according to the initial phase current; sampling through a bus sampling resistor to obtain a second bus current, wherein the second bus current is a bus current in an actual operating state; and determining an actual phase current according to the first bus current, the second bus current and the initial phase current.

[0006] Optionally, determining the actual phase current based on the first bus current, the second bus current and the initial phase current includes: determining a first proportional relationship between the first bus current and the second bus current; determining a proportional relationship between the initial phase current and the actual phase current based on the first proportional relationship, and calculating the actual phase current.

[0007] Optionally, the actual phase current I is calculated by the following formula: phase :

[0008] I phase =I phase0 *I bus1 / I bus0

[0009] Among them, I phase0 Represents the initial phase current, I bus0 Represents the first bus current, I bus1 Indicates the second bus current.

[0010] Optionally, determining the actual phase current based on the first bus current, the second bus current and the initial phase current includes: determining the actual internal resistance value of the power MOS tube based on the first bus current, the second bus current and the initial internal resistance value; determining the actual phase current based on the initial internal resistance value, the actual internal resistance value and the initial phase current.

[0011] Optionally, determining the actual internal resistance value of the power MOS tube according to the first bus current, the second bus current and the initial internal resistance value includes: determining a first proportional relationship between the first bus current and the second bus current; determining a second proportional relationship between the actual internal resistance value and the initial internal resistance value based on the first proportional relationship, and calculating the actual internal resistance value.

[0012] Optionally, determining the actual phase current according to the initial internal resistance value, the actual internal resistance value and the initial phase current includes: determining a proportional relationship between the initial phase current and the actual phase current based on the second proportional relationship, and calculating the actual phase current.

[0013] Optionally, before determining the actual phase current based on the first bus current, the second bus current and the initial phase current, it also includes: using the same cutoff frequency to low-pass filter the first bus current and the second bus current respectively to obtain the processed first bus current and the second bus current.

[0014] Optionally, the first bus current is calculated based on the initial phase current, including: obtaining a motor voltage given in an initial state and a bus voltage in the initial state obtained by sampling; calculating the output power based on the given motor voltage and the initial phase current; and according to the equal power principle, calculating the first bus current using the output power and the bus voltage.

[0015] In another aspect of an embodiment of the present invention, a motor phase current sampling device is provided, comprising: an acquisition module, used to acquire an initial internal resistance value of a power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state; a first sampling module, used to obtain an initial phase current in the initial state by sampling the initial internal resistance value of the power MOS tube; a calculation module, used to obtain a first bus current by calculation according to the initial phase current; a second sampling module, used to obtain a second bus current by sampling through a bus sampling resistor, wherein the second bus current is a bus current in an actual operating state; and a determination module, used to determine an actual phase current according to the first bus current, the second bus current and the initial phase current.

[0016] According to another aspect of an embodiment of the present invention, a sampling device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to perform the motor phase current sampling method as described above.

[0017] According to another aspect of the embodiments of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the motor phase current sampling method as described above.

[0018] The device or method provided by the present invention has the following technical effects:

[0019] 1. By using the relationship between the bus current and the internal resistance of the power MOS tube, as well as the relationship between the phase current and the internal resistance of the power MOS tube, the synergy between the changing law of the bus current and the changing law between the phase currents can be determined. In this way, the phase current and bus current determined by the internal resistance value of the power MOS tube in a known state can be used to calculate the phase current corresponding to the detected bus current in the actual operating state. There is no need to add a sampling resistor to each phase, nor is there a need to add a temperature sensor for temperature compensation, and the accurate phase current can be determined.

[0020] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of a preferred embodiment of the motor phase current sampling method of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a preferred embodiment of the motor phase current sampling device of the present invention;

[0023] Figure 3 1 is a diagram of the internal structure of the sampling device provided in the embodiment. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that the illustrations provided in the following embodiments are only used to illustrate the basic concept of the present invention in a schematic manner, and thus the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0026] While some exemplary embodiments of the present invention have been described for the purpose of illustration, it should be understood that the present invention may be implemented in other ways not specifically shown in the drawings.

[0027] The embodiment of the present invention provides a motor phase current sampling method, which is mainly used to sample the output current (i.e., phase current) on the three-phase bridge arm drive circuit of the motor, so as to achieve precise motor control. For the embodiment of the present invention, the specific circuit structure of the three-phase bridge arm drive circuit is not specifically limited, and a conventional three-phase bridge arm drive circuit can be used. The technical solution provided by the present application can realize accurate detection of phase current without adding sampling resistors and temperature sensors.

[0028] The motor phase current sampling method provided by the embodiment of the present invention is as follows: Figure 1 As shown, including:

[0029] Step S101, obtaining an initial internal resistance value of a power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state.

[0030] The initial internal resistance value of the power MOS tube may refer to the internal resistance value of the power MOS tube that can be determined under a known state, for example, the internal resistance value under normal temperature; or the internal resistance value when the temperature does not change when the motor is just started.

[0031] Step S102, obtaining an initial phase current in the initial state by sampling the initial internal resistance value of the power MOS tube.

[0032] By using the obtained initial internal resistance value of the power MOS tube, the initial phase current in the initial state can be sampled. That is to say, in the driving circuit, the internal resistance of the power MOS tube can be used as a sampling resistor to sample the initial phase current in the initial state. The initial phase current is not the phase current determined after the motor runs for a period of time. Instead, it is used as a reference for using an accurate phase current. Specifically, in an embodiment of the present invention, the VDS voltage loaded on the power MOS tube can be detected, and according to the relationship between voltage, current and resistance, the VDS voltage can be divided by the initial internal resistance value to obtain the initial phase current.

[0033] Step S103, obtaining a first bus current by calculation according to the initial phase current.

[0034] In the embodiment of the present invention, after the initial phase current is calculated, the bus current can be calculated according to the mathematical relationship between the phase current in the three-phase bridge arm and the bus current. Specifically, the output power on the bus is equal to the input power on each phase, and the bus current in the initial state, that is, the first bus current, can be calculated. The first bus current is the calculated bus current, that is, the bus current calculated when it is assumed that the internal resistance of the power MOS tube is the initial internal resistance value in the initial state.

[0035] As an optional implementation, the first bus current is calculated based on the initial phase current, including: obtaining a motor voltage given in an initial state and a bus voltage in the initial state obtained by sampling; calculating the output power based on the given motor voltage and the initial phase current; and according to the equal power principle, calculating the first bus current using the output power and the bus voltage.

[0036] According to the equal power principle, the output power is equal to the input power, and the power is obtained by multiplying the voltage by the current. Therefore, after obtaining the motor voltage and the initial phase current, the output power of each phase can be calculated according to the relationship between the phases of the three-phase bridge arm drive circuit, and the total output power can be added up; then divided by the bus voltage to obtain the bus current, which is the first bus current.

[0037] Step S104, sampling by a bus sampling resistor to obtain a second bus current, wherein the second bus current is a bus current in an actual operating state.

[0038] In this embodiment, the second bus current is the bus current in the actual operating state, that is, when the motor is in the actual control operation process, the second bus current is sampled by using the sampling resistor set on the bus. Specifically, when the resistance value of the bus sampling resistor is known, the second bus current can be calculated by detecting the voltage across the bus sampling resistor, and the voltage sampling circuit can be an existing sampling circuit, which is not specifically limited in the embodiment of the present invention.

[0039] Step S105 , determining an actual phase current according to the first bus current, the second bus current and the initial phase current.

[0040] In the embodiment of the present invention, since the initial phase current is the phase current obtained based on the initial internal resistance value, and the first bus current is the bus current determined based on the initial internal resistance value, the second bus current is the bus current in the actual operating state. Under the premise that the internal resistance value of the power MOS tube is fixed, the relationship between the bus current and the phase current can be determined, and it can be considered that the relationship remains basically unchanged as the internal resistance value changes. Then, based on the relationship, the specific value of the actual phase current can be determined according to the second bus current.

[0041] According to an embodiment of the present invention, the relationship between the bus current and the internal resistance of the power MOS tube, as well as the relationship between the phase current and the internal resistance of the power MOS tube, is used to determine the synergy between the changing law of the bus current and the changing law between the phase currents. In this way, the phase current and the bus current determined by the internal resistance value of the power MOS tube in a known state can be used to calculate the phase current corresponding to the detected bus current in the actual operating state. There is no need to add a sampling resistor to each phase, nor is there a need to add a temperature sensor for temperature compensation, and the accurate phase current can be determined.

[0042] As an optional implementation, in an embodiment of the present invention, the above-mentioned step S105, determining the actual phase current based on the first bus current, the second bus current and the initial phase current, includes: determining a first proportional relationship between the first bus current and the second bus current; determining a proportional relationship between the initial phase current and the actual phase current based on the first proportional relationship, and calculating the actual phase current.

[0043] Specifically, the actual phase current I can be calculated by the following formula: phase :

[0044] I phase =Iphase0 *I bus1 / I bus0

[0045] Among them, I phase0 Represents the initial phase current, I bus0 Represents the first bus current, I bus1 Indicates the second bus current.

[0046] From the above formula, it can be seen that the ratio between the bus current under the actual operating state and the bus current under the known state, and the ratio between the phase current under the actual operating state and the initial phase current under the known state, the two ratios are the same, thus, the actual phase current can be calculated.

[0047] The specific derivation process of the above formula is as follows:

[0048] Initial phase current I phase0 And the known phase voltage U phase Estimate motor input power P0:

[0049] I phase0 *U phase =P0 (1)

[0050] Actual phase current I phase And the known phase voltage U phase Calculate the motor input power P:

[0051] I phase *U phase =P (2)

[0052] By estimating the bus current I bus0 (i.e. the first bus current) and the known bus voltage U bus (Control given bus voltage) Estimate motor input power:

[0053] I bus0 *U bus =P0 (3)

[0054] The actual bus current (i.e., the second bus current) and the known bus voltage U bus Calculate the motor input power:

[0055] I bus1 *U bus =P (4)

[0056] According to the above four formulas, the following conclusions can be derived: phase =I phase0 *I bus1 / I bus0。

[0057] As an alternative implementation to the above embodiment, in the above step S105 in the embodiment of the present invention, the actual phase current is determined based on the first bus current, the second bus current and the initial phase current, including: determining the actual internal resistance value of the power MOS tube based on the first bus current, the second bus current and the initial internal resistance value; determining the actual phase current based on the initial internal resistance value, the actual internal resistance value and the initial phase current.

[0058] The law similar to the above embodiment is the synergy between the changing law of the bus current and the changing law of the phase current. Similarly, the changing law of the bus current and the changing law of the internal resistance of the power MOS tube also have synergy. Therefore, the actual internal resistance value of the power MOS tube in the actual operation state (at a certain moment) can be calculated. The actual phase current is calculated by using the synergy between the changing law of the internal resistance value and the changing law of the phase current.

[0059] In the embodiment of the present invention, the actual internal resistance value of the power MOS tube at the time of operation can be accurately calculated, and therefore, it can be used to calibrate the relationship between the internal resistance value and the phase current or even the temperature, thereby facilitating applications in other aspects.

[0060] As a further optional implementation, the above step, determining the actual internal resistance value of the power MOS tube based on the first bus current, the second bus current and the initial internal resistance value, includes: determining a first proportional relationship between the first bus current and the second bus current; determining a second proportional relationship between the actual internal resistance value and the initial internal resistance value based on the first proportional relationship, and calculating the actual internal resistance value.

[0061] Specifically, the actual internal resistance value R of the power MOS tube can be calculated using the following formula: ds :

[0062] I bus0 / I bus1 =R ds / R type

[0063] Among them, I bus0 Represents the first bus current, I bus1 Represents the second bus current, R type Indicates the initial internal resistance value.

[0064] Further, determining the actual phase current according to the initial internal resistance value, the actual internal resistance value and the initial phase current includes: determining a proportional relationship between the initial phase current and the actual phase current based on the second proportional relationship, and calculating the actual phase current.

[0065] The above internal resistance value R ds The calculation formula can be derived from the following formula:

[0066] I phase =I phase0 *I bus1 / I bus0 (5)

[0067] The voltages at both ends of the MOS tube are equal:

[0068] I phase *R ds =I phase0 *R type (6)

[0069] According to the above two formulas (5) and (6), the following conclusions can be derived:

[0070] I bus0 / I bus1 =R ds / R type。

[0071] Specifically, the actual phase current can be calculated using the following formula:

[0072] I phase / I phase0 =R ds / R type

[0073] This formula means that when the voltage VDS loaded on the power MOS tube is equal, the product of the internal resistance value and the phase current in the initial state is equal to the product of the internal resistance value and the actual internal resistance value in the actual operating state. This relationship is used to determine the actual phase current.

[0074] It can be foreseen that the method for determining the actual phase current in this embodiment is to determine the internal resistance value of the power MOS tube as an intermediate quantity, thereby providing more electrical parameters and facilitating applications in other aspects.

[0075] As an optional implementation, in an embodiment of the present invention, in order to reduce the volatility of the sampled phase current or the calculated internal resistance of the power MOS tube, the first bus current and the second bus current can be filtered. Specifically, the above step S105, before determining the actual phase current based on the first bus current, the second bus current and the initial phase current, also includes: using the same cutoff frequency to perform low-pass filtering on the first bus current and the second bus current respectively to obtain the processed first bus current and the second bus current.

[0076] The cutoff frequency can be set based on experience or determined based on experimental data. Its purpose is to filter out high-frequency waves and achieve low-pass filtering, thereby reducing the volatility of the internal resistance value and the volatility of the phase current, thereby achieving the purpose of reducing interference and noise.

[0077] After filtering, the filtered first bus current and the second bus current are used for subsequent calculations. For example, the filtered first bus current is I bus01 , the processed second bus current is I bus11 , then in the calculation process of the above embodiment, it is only necessary to replace the I originally involved in the calculation bus0 Replace with I bus01 , I bus1 Replace with I bus11 The other formula parameters remain unchanged.

[0078] The motor phase current sampling method provided in the dietary embodiment of the present invention can be applied to the sampling equipment of the motor, mainly used to sample the electrical parameters in the motor, including current, voltage, resistance, etc., so as to provide accurate electrical parameters for motor control and realize precise control of the motor.

[0079] The embodiment of the present invention further provides a motor phase current sampling device, which can be used to execute the above motor phase current sampling method, such as Figure 2 As shown, the device comprises:

[0080] The acquisition module 201 is used to acquire an initial internal resistance value of the power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state.

[0081] The first sampling module 202 is used to obtain the initial phase current in the initial state by sampling the initial internal resistance value of the power MOS tube.

[0082] The calculation module 203 is used to calculate the first bus current according to the initial phase current.

[0083] The second sampling module 204 is used to obtain a second bus current by sampling through a bus sampling resistor, wherein the second bus current is the bus current in an actual operating state.

[0084] The determination module 205 is used to determine the actual phase current according to the first bus current, the second bus current and the initial phase current.

[0085] According to an embodiment of the present invention, the relationship between the bus current and the internal resistance of the power MOS tube, as well as the relationship between the phase current and the internal resistance of the power MOS tube, is used to determine the synergy between the changing law of the bus current and the changing law between the phase currents. In this way, the phase current and the bus current determined by the internal resistance value of the power MOS tube in a known state can be used to calculate the phase current corresponding to the detected bus current in the actual operating state. There is no need to add a sampling resistor to each phase, nor is there a need to add a temperature sensor for temperature compensation, and the accurate phase current can be determined.

[0086] For the specific implementation of the method, please refer to the above method embodiment, which will not be repeated here.

[0087] In one embodiment of the present invention, a sampling device is also provided, and its internal structure diagram can be shown as follows: Figure 3 As shown. The sampling device includes a processor and a memory connected through a system bus, and may also include a display screen and an input device. Among them, the processor of the sampling device is used to provide computing and control capabilities. The memory of the sampling device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. When the computer program is executed by the processor, a motor adaptive adaptation method is implemented. The sampling device may also include a display screen and an input device, and the display screen may be a liquid crystal display or an electronic ink display screen. The input device of the sampling device may be a touch layer covered on the display screen, or a button, trackball or touchpad provided on the housing of the sampling device, or an external keyboard, touchpad, etc.

[0088] Those skilled in the art will understand that Figure 3 The structure shown in the figure is merely a block diagram of a portion of the structure related to the scheme of the present application, and does not constitute a limitation on the sampling device to which the scheme of the present application is applied. The specific sampling device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0089] In one embodiment, a sampling device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0090] Acquire an initial internal resistance value of the power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state;

[0091] Sampling the initial internal resistance value of the power MOS tube to obtain the initial phase current in the initial state;

[0092] Calculate the first bus current according to the initial phase current;

[0093] The second bus current is obtained by sampling the bus sampling resistor, wherein the second bus current is the bus current in the actual operation state;

[0094] An actual phase current is determined according to the first bus current, the second bus current and the initial phase current.

[0095] In one embodiment, a readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0096] Acquire an initial internal resistance value of the power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state;

[0097] Sampling the initial internal resistance value of the power MOS tube to obtain the initial phase current in the initial state;

[0098] Calculate the first bus current according to the initial phase current;

[0099] The second bus current is obtained by sampling the bus sampling resistor, wherein the second bus current is the bus current in the actual operation state;

[0100] An actual phase current is determined according to the first bus current, the second bus current and the initial phase current.

[0101] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0102] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0103] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A motor phase current sampling method, characterized in that: include: Acquire an initial internal resistance value of the power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state; Sampling the initial internal resistance value of the power MOS tube to obtain the initial phase current in the initial state; A first bus current is calculated according to the initial phase current; the first bus current is a bus current determined based on an initial internal resistance value in an initial state; The second bus current is obtained by sampling the bus sampling resistor, wherein the second bus current is the bus current in the actual operation state; An actual phase current is determined according to the first bus current, the second bus current and the initial phase current.

2. The motor phase current sampling method according to claim 1, characterized in that: The determining the actual phase current according to the first bus current, the second bus current and the initial phase current comprises: Determining a first proportional relationship between the first bus current and the second bus current; The proportional relationship between the initial phase current and the actual phase current is determined based on the first proportional relationship, and the actual phase current is obtained by calculation.

3. The motor phase current sampling method according to claim 1, characterized in that: The actual phase current I is calculated by the following formula phase : I phase =I phase0 *I bus1 / I bus0 Among them, I phase0 represents the initial phase current, I bus0 Represents the first bus current, I bus1 Indicates the second bus current.

4. The motor phase current sampling method according to claim 1, characterized in that: The determining the actual phase current according to the first bus current, the second bus current and the initial phase current comprises: Determining an actual internal resistance value of the power MOS tube according to the first bus current, the second bus current and the initial internal resistance value; The actual phase current is determined according to the initial internal resistance value, the actual internal resistance value and the initial phase current.

5. The motor phase current sampling method according to claim 4, characterized in that: The determining the actual internal resistance value of the power MOS tube according to the first bus current, the second bus current and the initial internal resistance value comprises: Determining a first proportional relationship between the first bus current and the second bus current; A second proportional relationship between the actual internal resistance value and the initial internal resistance value is determined based on the first proportional relationship, and the actual internal resistance value is obtained by calculation.

6. The motor phase current sampling method according to claim 5, characterized in that: The determining the actual phase current according to the initial internal resistance value, the actual internal resistance value and the initial phase current includes: The proportional relationship between the initial phase current and the actual phase current is determined based on the second proportional relationship, and the actual phase current is obtained by calculation.

7. The motor phase current sampling method according to claim 1, characterized in that: Before determining the actual phase current according to the first bus current, the second bus current and the initial phase current, the method further includes: The first bus current and the second bus current are respectively subjected to low-pass filtering processing using the same cut-off frequency to obtain processed first bus current and second bus current.

8. The motor phase current sampling method according to claim 1, characterized in that: The step of calculating the first bus current according to the initial phase current includes: Obtain the motor voltage given in the initial state and the bus voltage in the initial state obtained by sampling; Calculating the output power according to the given motor voltage and the initial phase current; According to the equal power principle, the first bus current is calculated using the output power and the bus voltage.

9. A motor phase current sampling device, characterized in that: include: An acquisition module, used to acquire an initial internal resistance value of the power MOS tube, wherein the initial internal resistance value is an internal resistance value determined by the power MOS tube in an initial state; A first sampling module, configured to obtain an initial phase current in the initial state by sampling the initial internal resistance value of the power MOS tube; A calculation module, configured to calculate a first bus current according to the initial phase current; the first bus current is a bus current determined based on an initial internal resistance value in an initial state; A second sampling module, used for sampling through a bus sampling resistor to obtain a second bus current, wherein the second bus current is a bus current in an actual operating state; A determination module is used to determine an actual phase current according to the first bus current, the second bus current and the initial phase current.

10. A sampling device, comprising at least one processor; and a memory in communication with the at least one processor; wherein: The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to perform the motor phase current sampling method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the motor phase current sampling method according to any one of claims 1 to 8.

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