Method and device for calculating resistance value of stator resistor, motor and storage medium

Abstract

The invention discloses a stator resistor resistance value calculation method and device, a motor and a storage medium, and the method comprises the steps: respectively injecting d-axis reference current to the d-axis of the motor and injecting q-axis reference current to the q-axis of the motor when the motor is in a static state, so as to obtain d-axis feedback current and d-axis reference voltage, and the q-axis reference current is 0; determining a relation curve of the d-axis feedback current and the d-axis reference voltage based on the d-axis feedback current and the d-axis reference voltage; a first calculation formula and a second calculation formula are determined based on the relation curve, the first calculation formula is used for calculating the resistance value of the stator resistor, and the second calculation formula is used for calculating the voltage error; and performing sliding processing on the real-time resistance value of the stator resistor calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the resistance value of the stator resistor. The precision of calculating the resistance value of the stator resistor can be improved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a method, apparatus, motor, and storage medium for calculating stator resistance. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in servo motor control due to their high efficiency and excellent speed regulation performance. In servo motor control systems, the stator resistance is a key parameter of the current controller, typically used to calculate the PID parameters of the current loop, enabling automatic adjustment of the current controller parameters. However, current methods for calculating stator resistance often fail to consider voltage errors caused by inverter nonlinearity, resulting in low calculation accuracy. Summary of the Invention

[0003] This invention provides a method, apparatus, motor, and storage medium for calculating stator resistance, aiming to solve the problem of poor accuracy in current methods for calculating stator resistance.

[0004] In a first aspect, embodiments of the present invention provide a method for calculating the stator resistance value, applied to a motor, the method comprising:

[0005] When the motor is stationary, a d-axis reference current is injected into the d-axis of the motor and a q-axis reference current is injected into the q-axis of the motor to obtain the d-axis feedback current and the d-axis reference voltage, wherein the q-axis reference current is 0.

[0006] The relationship curve between the d-axis feedback current and the d-axis reference voltage is confirmed based on the d-axis feedback current and the d-axis reference voltage.

[0007] Based on the relationship curve, a first calculation formula and a second calculation formula are confirmed, wherein the first calculation formula is used to calculate the resistance value of the stator resistor, and the second calculation formula is used to calculate the voltage error.

[0008] The real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula are subjected to a sliding process to confirm the stator resistance value.

[0009] Secondly, embodiments of the present invention also provide a device for calculating the stator resistance value, applied to a motor, the device comprising:

[0010] The first injection unit is used to inject a d-axis reference current into the d-axis of the motor and a q-axis reference current into the q-axis of the motor respectively when the motor is in a stationary state to obtain a d-axis feedback current and a d-axis reference voltage, wherein the q-axis reference current is 0;

[0011] The first confirmation unit is used to confirm the relationship curve between the d-axis feedback current and the d-axis reference voltage based on the d-axis feedback current and the d-axis reference voltage.

[0012] The second confirmation unit is used to confirm the first calculation formula and the second calculation formula based on the relationship curve, wherein the first calculation formula is used to calculate the resistance value of the stator resistor and the second calculation formula is used to calculate the voltage error.

[0013] The first calculation unit is used to perform a sliding process on the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the stator resistance value.

[0014] Thirdly, embodiments of the present invention also provide an electric motor, which includes a memory and a processor connected to the memory, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0015] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the above-described method.

[0016] This invention provides a method, apparatus, motor, and storage medium for calculating stator resistance. The method includes: injecting a d-axis reference current and a q-axis reference current into the motor while it is stationary to obtain a d-axis feedback current and a d-axis reference voltage, wherein the q-axis reference current is 0; confirming the relationship curve between the d-axis feedback current and the d-axis reference voltage based on the relationship curve; confirming a first calculation formula and a second calculation formula based on the relationship curve, wherein the first calculation formula is used to calculate the stator resistance value, and the second calculation formula is used to calculate the voltage error; and performing a sliding process on the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the stator resistance value. This invention provides an embodiment of the invention that injects d-axis reference current and q-axis reference current into the d-axis and q-axis respectively to obtain d-axis reference voltage and d-axis feedback current. Based on the d-axis reference voltage and d-axis feedback current, the relationship curve between the two is confirmed. Then, the first calculation formula and the second calculation formula are confirmed through the relationship curve. The values ​​of the first calculation formula and the second calculation formula are then subjected to sliding processing to calculate the stator resistance value. This can eliminate the voltage error caused by the nonlinearity of the inverter and improve the calculation accuracy. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the method for calculating the stator resistance value provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the motor control system provided in an embodiment of the present invention;

[0020] Figure 3 This is a graph of d-axis current and d-axis voltage provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the first sub-process of the method for calculating the stator resistance value provided in the embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the second sub-process of the method for calculating the stator resistance value provided in the embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the third sub-process of the method for calculating the stator resistance value provided in the embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the third sub-process of the method for calculating the stator resistance value provided in the embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the third sub-process of the method for calculating the stator resistance value provided in the embodiment of the present invention;

[0026] Figure 9 This is a schematic block diagram of a device for calculating the stator resistance value according to an embodiment of the present invention;

[0027] Figure 10 This is a schematic block diagram of a motor provided in an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be understood that, when used in this specification and the appended claims, the terms “comprising” and “including” indicate the presence of the described features, integrals, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0031] Please see Figure 1 , Figure 1 This is a flowchart illustrating the method for calculating the stator resistance value provided in an embodiment of the present invention. This method can be applied to motors, such as permanent magnet motors, and can eliminate voltage errors caused by inverter nonlinearity, thereby improving the accuracy of the calculated stator resistance value. The method includes steps S100 to S130.

[0032] S100, when the motor is in a stationary state, inject a d-axis reference current into the d-axis of the motor and a q-axis reference current into the q-axis of the motor to obtain a d-axis feedback current and a d-axis reference voltage, wherein the q-axis reference current is 0.

[0033] In this embodiment of the invention, when the motor is in a stationary state, a ramp-shaped d-axis reference current I is injected into the d-axis of the motor. dref Among them, the current command i from the input d-axis current loop PI controller can be obtained. d (t), i d (t) represents the current command in ramp form, which is used as the d-axis reference current I. dref Inject d-axis current loop. d The maximum value of (t) should be limited to the smaller of the maximum current that the drive controller or the permanent magnet synchronous motor can withstand. Similarly, when the motor is stationary, a q-axis reference current I is injected into the q-axis of the motor. qref And the q-axis reference current I qref A value of 0 ensures that the motor does not generate rotational torque.

[0034] After current injection is completed, the three-phase current I of the motor is acquired through current sampling hardware. a I b and I cAfter the second coordinate transformation, it is converted into the d-axis feedback current I. d The d-axis current loop PI controller is based on the d-axis reference current I. dref With d-axis feedback current I d The error is adjusted proportionally to integrally, and the output d-axis reference voltage U is obtained. dref .

[0035] S110, Based on the d-axis feedback current and the d-axis reference voltage, confirm the relationship curve between the d-axis feedback current and the d-axis reference voltage.

[0036] In this embodiment of the invention, after obtaining the d-axis feedback current and the d-axis reference voltage, the relationship curve between the d-axis feedback current and the d-axis reference voltage can be determined based on these two parameters. For example... Figure 3 As shown, Figure 3 To illustrate the d-axis current and d-axis voltage curves considering the nonlinear effects of the inverter, as shown below... Figure 3 middle u d The vertical axis represents the voltage along the d-axis; i d The horizontal axis represents the d-axis current. Curve 1 represents the i-axis. d &u d Curve 1 represents the relationship between d-axis current and d-axis voltage; Curve 2 is i d &Δu d The curves represent the relationship between the d-axis current and d-axis voltage error (inverter nonlinear characteristic curves). Curve 1 shows the d-axis voltage including the stator resistance voltage drop and the voltage error caused by inverter nonlinearity. Curve 2 can be obtained by subtracting the stator resistance voltage drop from the d-axis voltage in curve 1. ΔU and ΔI are the saturation values ​​(i.e., saturation voltage threshold and saturation current threshold) of the inverter's nonlinear voltage and current, respectively. Before the d-axis current exceeds the current saturation threshold ΔI (in the linear region and intermediate state), the error voltage Δu... d It exhibits nonlinear growth; once the d-axis current exceeds the current saturation threshold ΔI (enters the saturation region), the error voltage Δu... d The constant value is ΔU.

[0037] Depend on Figure 3 As can be seen from curves 1 and 2, before the d-axis current crosses the current saturation threshold ΔI, the error voltage Δu d It exhibits nonlinear growth; once the d-axis current exceeds the current saturation threshold ΔI, the error voltage Δu... d Let ΔU be a constant value. At this point, the voltage and current have a linear relationship, and the slope of this relationship represents the resistance value. By identifying the resistance value through linear regression, the equation of the straight line in the saturation region of curve 1 is:

[0038] u d =R s i d +Δud (1)

[0039] Perform a least-squares fit on the n points measured by feedback, and assume:

[0040]

[0041] Then, by the principle of extrema, we get:

[0042]

[0043] After transforming and rearranging formula (3), we get:

[0044]

[0045] Among them, R s The real-time stator resistance value, Δu d For real-time voltage error, j≤n, where j and n are both positive integers, i dj It is the d-axis feedback current corresponding to the j-th d-axis reference current, u j It is the d-axis reference voltage corresponding to the j-th d-axis reference current.

[0046] S120, based on the relationship curve, confirm the first calculation formula and the second calculation formula, wherein the first calculation formula is used to calculate the resistance value of the stator resistor, and the second calculation formula is used to calculate the voltage error.

[0047] In this embodiment of the invention, the first calculation formula is formula (4), and the second calculation formula is formula (5). The real-time stator resistance value can be calculated using formula (4), and the real-time voltage error can be calculated using formula (5). It is understood that multiple d-axis feedback currents and d-axis reference voltages can be obtained by injecting different d-axis reference currents multiple times, thereby obtaining multiple real-time stator resistance values ​​and real-time voltage errors.

[0048] S130, the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula are subjected to a sliding process to confirm the stator resistance value.

[0049] In this embodiment of the invention, during actual operation, the d-axis current and d-axis voltage do not directly enter the saturation region. The real-time stator resistance value and real-time voltage error calculated by the first calculation formula and the second calculation formula include data from the non-saturation region. The error can be corrected by performing a sliding process on the obtained multiple real-time stator resistance values ​​and real-time voltage errors, thereby obtaining an accurate stator resistance value. This can eliminate the nonlinear effects of the inverter and improve the calculation accuracy.

[0050] In some embodiments, such as in embodiments of the present invention, as Figure 4As shown, step S100 includes steps S101-S103.

[0051] S101, obtain the d-axis reference voltage and q-axis reference voltage of the motor, and perform a first coordinate transformation on the d-axis reference voltage and the q-axis reference voltage to obtain a first reference voltage and a second reference voltage;

[0052] S102, a drive signal is generated based on the first reference voltage and the second reference voltage, and the inverter of the motor is driven to output three-phase voltage through the drive signal;

[0053] S103, obtain the three-phase current of the motor, and perform a second coordinate transformation on the three-phase current to obtain the d-axis feedback current.

[0054] In embodiments of the present invention, such as Figure 2 As shown, Figure 2 This is a schematic diagram of a permanent magnet synchronous motor control system. The method for calculating the stator resistance value provided by this invention can be applied to this permanent magnet synchronous motor control system. Figure 2 Middle I dref It is the d-axis reference current, I qref It is the q-axis reference current; I d It is the d-axis feedback current, I q It is the q-axis feedback current; i d (t) is the injected current in the form of a ramp; PI is a current loop proportional-integral controller; U dref It is the d-axis reference voltage, U qref dq / αβ is the q-axis reference voltage; dq / αβ is the inverse Park transformation module (first coordinate transformation module); abc / dq is the coordinate transformation module from the natural coordinate system to the two-phase rotating coordinate system (second coordinate transformation module); U αref It is the reference voltage along the α-axis of the stationary coordinate system, U βref It is the β-axis reference voltage in the stationary coordinate system; SVPWM is the space vector modulation algorithm module; U dc This is the DC power supply bus voltage of the inverter module; I a I b I c These are the three-phase currents of the permanent magnet synchronous motor; PMSM (Permanent Magnet Synchronous Motor) is the permanent magnet synchronous motor module; θ e It is the electrical angle of the motor rotor; R s It is the stator resistance value of the motor.

[0055] Figure 2 Injecting a ramp-shaped reference current I into the d-axis dref q-axis injection I qref(Ensure the motor does not rotate). The PI controllers for the d-axis and q-axis are based on the reference current I. dref and I qref With feedback current I d The error, output d-axis reference voltage U dref and q-axis reference voltage U qref d-axis reference voltage U dref and q-axis reference voltage U qref The reference voltage U, converted to the α-axis and β-axis of the stationary coordinate system by the first coordinate transformation module, αref U βref ;SVPWM module for U αref U βref Modulation is performed to generate six pulse signals, which control the inverter to convert the DC voltage U dc Converted to three-phase AC voltage to drive the PMSM. Motor three-phase current I a I b I c The current is obtained through sampling and converted into d-axis and q-axis feedback current I by the second coordinate transformation module. d and I q The feedback is sent to the current loop PI controller to form a closed-loop control.

[0056] The first coordinate transformation formula can be:

[0057]

[0058] The formula for the second coordinate transformation can be:

[0059]

[0060] Since the motor is stationary, then θ e Since it is always 0, the d-axis feedback current can be obtained through the first coordinate transformation formula and the second coordinate transformation formula.

[0061] In some embodiments, such as in embodiments of the present invention, as Figure 5 As shown, step S100 further includes steps S104-S105.

[0062] S104, Obtain the d-axis feedback current and the d-axis reference current;

[0063] S105, confirm the d-axis reference voltage based on the d-axis feedback current and the d-axis reference current.

[0064] In this embodiment of the invention, with the motor stationary, a ramp-shaped d-axis reference current I is first injected into the d-axis current loop. dref At the same time, the q-axis reference current I qrefSet it to 0 and inject the q-axis current loop. At this time, the PI controller of the d-axis current loop adjusts proportionally and integrally according to the error between the d-axis reference current I dref and the d-axis feedback current I d , and the finally output voltage command is the d-axis reference voltage U dref . <0OO0263>In some embodiments, for example, in the embodiment of the present invention, as Figure 6 shown, the step S130 further includes steps S131-S132.

[0066] S131, perform a sliding process on the first calculation formula and the second calculation formula to obtain a modified first calculation formula and a modified second calculation formula;

[0067] S132, confirm whether the motor enters the saturation region according to the real-time voltage error, and when the motor enters the saturation region, use the real-time stator resistance value that meets the first preset condition as the value of the stator resistance.

[0068] In the embodiment of the present invention, the first calculation formula and the second calculation formula can be first subjected to a sliding process to correct the first calculation formula and the second calculation formula to obtain a modified first calculation formula and a modified second calculation formula. The modified first calculation formula is:

[0069]

[0070] The modified second calculation formula is:

[0071]

[0072] where L is the window length of the sliding window, and its sliding step can vary from 1 to L. The value of L needs to be much smaller than the number of sampling points n, that is, L << n. The value is usually the number of sampling points in 1 to 2 milliseconds (ms), generally only dozens. For example, if an interrupt period is 62.5 microseconds and there are 16000 data points in 1 s, then the length of L can take any value from 16 to 32. If the value of L is larger, the accuracy will decrease. For example, if L is directly taken as 16000, it will be insensitive to the voltage / current changes in the linear region and the intermediate state. If the value of L is smaller, such as L taking 2 or 3, considering the sampling error, the fluctuation of the calculation result will be very large. Compared with the sliding window with a step of 1, the calculation frequency of the sliding window with a step of L changes from calculating R s and ΔU once per cycle to calculating R sAnd ΔU. The real-time stator resistance and real-time voltage error can be calculated using the modified first calculation formula and the modified second calculation formula. Then, based on the real-time voltage error, it is confirmed whether the saturation region has been entered. When the saturation region has been entered, the real-time stator resistance value that meets the first preset condition is taken as the stator resistance value.

[0073] In some embodiments, such as in embodiments of the present invention, as Figure 7 As shown, step S132 further includes steps S1321-S1322.

[0074] S1321, confirm whether there are two consecutive windows with equal real-time voltage errors;

[0075] S1322, if the real-time voltage error is equal in two consecutive windows, then the motor is confirmed to have entered the saturation region.

[0076] In this embodiment of the invention, it can be determined whether the saturation region has been entered by confirming whether the real-time voltage errors of two consecutive windows are approximately equal. When the real-time voltage errors of two consecutive windows are approximately equal, it is confirmed that the saturation region has been entered.

[0077] In some embodiments, such as in embodiments of the present invention, as Figure 8 As shown, step S132 further includes steps S1323-S1324.

[0078] S1323, confirm whether there are two consecutive windows with the same real-time stator resistance value;

[0079] S1324, if there are two consecutive windows with equal real-time stator resistance values, then the real-time stator resistance value is taken as the stator resistance value.

[0080] In this embodiment of the invention, after entering the saturation region, the real-time stator resistance value can be calculated using the modified first calculation formula, and it is confirmed whether the real-time stator resistance values ​​of two consecutive windows are equal. If the real-time stator resistance values ​​of two consecutive windows are equal, then the real-time stator resistance value is taken as the stator resistance value.

[0081] For example, when the motor is stationary, a d-axis reference current I is injected into the d-axis. dref (Range 0-5A, maximum 5A), q-axis current remains 0. Three-phase current I is acquired via a current sampling chip. a I b I c The d-axis feedback current I is obtained after the first coordinate transformation. d Simultaneously record the corresponding d-axis reference voltage U. dref Let the sliding window length L = 5, for the acquired I... d and Udref Perform sliding processing:

[0082] Window 1 data I d 0.2~1.0A, U dref (0.8~4.2V): Calculated value: R s (1)=4.1,Δu d (1) = 0.3V;

[0083] Second window data I d 0.5~1.3A, U dref 2.1~5.4V: Calculated R s (2) = 4.0, Δu d (2) = 0.4V;

[0084] 10th window data I d 4.5~5.0A, U dref 18.2~20.0V: Calculated R s (10)=4.0,Δu d (10) = 2.0V;

[0085] 11th window data I d 4.6~5.0A, U dref (18.6~20.0V): Calculated R s (11)=4.0,Δu d (11) = 2.0V).

[0086] Therefore, we can know that Δu of the 10th and 11th windows d Both are approximately equal to 2.0V, indicating they have entered the saturation region; and R s (10)=R s (11) = 4.0, therefore the output identification result R is... s =4.0, which is the resistance value of the stator resistor of the motor.

[0087] The stator resistance calculation method disclosed in this invention obtains the d-axis reference voltage and d-axis feedback current by injecting d-axis reference current and q-axis reference current into the d-axis and q-axis respectively, and confirms the relationship curve between the d-axis reference voltage and d-axis feedback current. Then, the first calculation formula and the second calculation formula are confirmed through the relationship curve, and the values ​​of the first calculation formula and the second calculation formula are subjected to sliding processing to calculate the stator resistance value. This can eliminate the voltage error caused by the nonlinearity of the inverter and improve the calculation accuracy.

[0088] Figure 9 This is a schematic block diagram of a stator resistance calculation device 200 provided in an embodiment of the present invention. Figure 9 As shown, corresponding to the above method for calculating stator resistance value, the present invention also provides a stator resistance value calculation device 200. This stator resistance value calculation device 200 includes a unit for performing the above-described method for calculating stator resistance value. Specifically, please refer to... Figure 9 The stator resistance calculation device 200 includes a first injection unit 201, a first confirmation unit 202, a second confirmation unit 203, and a first calculation unit 204.

[0089] The first injection unit 201 is used to inject a d-axis reference current into the d-axis of the motor and a q-axis reference current into the q-axis of the motor respectively when the motor is in a stationary state to obtain a d-axis feedback current and a d-axis reference voltage, wherein the q-axis reference current is 0.

[0090] The first confirmation unit 202 is used to confirm the relationship curve between the d-axis feedback current and the d-axis reference voltage based on the d-axis feedback current and the d-axis reference voltage;

[0091] The second confirmation unit 203 is used to confirm the first calculation formula and the second calculation formula based on the relationship curve, wherein the first calculation formula is used to calculate the resistance value of the stator resistor and the second calculation formula is used to calculate the voltage error.

[0092] The first calculation unit 204 is used to perform a sliding process on the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the stator resistance value.

[0093] In some embodiments, such as this embodiment, the first injection unit 201 further includes a first acquisition unit, a first generation unit, and a second acquisition unit.

[0094] The first acquisition unit is used to acquire the d-axis reference voltage and the q-axis reference voltage of the motor, and to perform a first coordinate transformation on the d-axis reference voltage and the q-axis reference voltage to obtain a first reference voltage and a second reference voltage.

[0095] The first generation unit is used to generate a drive signal based on the first reference voltage and the second reference voltage, and drive the inverter of the motor to output three-phase voltage through the drive signal;

[0096] The second acquisition unit is used to acquire the three-phase current of the motor and perform a second coordinate transformation on the three-phase current to obtain the d-axis feedback current.

[0097] In some embodiments, such as this one, the first injection unit 201 further includes a third acquisition unit and a third confirmation unit.

[0098] The third acquisition unit is used to acquire the d-axis feedback current and the d-axis reference current.

[0099] The third confirmation unit is used to confirm the d-axis reference voltage based on the d-axis feedback current and the d-axis reference current.

[0100] In some embodiments, such as this one, the first calculation unit 204 further includes a second calculation unit and a fourth confirmation unit.

[0101] The second calculation unit is used to perform a sliding process on the first calculation formula and the second calculation formula to obtain the modified first calculation formula and the modified second calculation formula.

[0102] The fourth confirmation unit is used to confirm whether the motor has entered the saturation region based on the real-time voltage error, and when the motor enters the saturation region, the real-time stator resistance value that meets the first preset condition is used as the stator resistance value.

[0103] In some embodiments, such as this one, the fourth confirmation unit includes a fifth confirmation unit and a sixth confirmation unit.

[0104] The fifth confirmation unit is used to confirm whether there are two consecutive windows with equal real-time voltage errors.

[0105] The sixth confirmation unit confirms that the motor has entered the saturation region if the real-time voltage error is equal in two consecutive windows.

[0106] In some embodiments, such as this one, the fourth confirmation unit includes a seventh confirmation unit and an eighth confirmation unit.

[0107] The seventh confirmation unit is used to confirm whether there are two consecutive windows with equal real-time stator resistance values.

[0108] The eighth confirmation unit is used to take the real-time stator resistance value as the stator resistance value if there are two consecutive windows with equal real-time stator resistance values.

[0109] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the above-mentioned stator resistance value calculation device and each unit can be referred to the corresponding description in the foregoing method embodiments. For the sake of convenience and brevity, it will not be repeated here.

[0110] The aforementioned device for calculating the stator resistance value can be implemented as a computer program, which can be used in various ways, such as... Figure 10 The motor shown is running.

[0111] Please see Figure 10, Figure 10 This is a schematic block diagram of a motor provided in an embodiment of this application. It can be a terminal or a server. The terminal can be an electronic device with communication functions, such as a smartphone, tablet, laptop, desktop computer, personal digital assistant, or wearable device. The server can be a standalone server or a server cluster composed of multiple servers.

[0112] See Figure 10 The motor 300 includes a processor 302, a memory, and an interface 307 connected via a system bus 301. The memory may include a non-volatile storage medium 303 and internal memory 304.

[0113] The non-volatile storage medium 303 can store an operating system 3031 and a computer program 3032. When the computer program 3032 is executed, it causes the processor 302 to execute a method for calculating the stator resistance value.

[0114] The processor 302 provides computing and control capabilities to support the operation of the entire motor 300.

[0115] The internal memory 304 provides an environment for the operation of the computer program 3032 in the non-volatile storage medium 303. When the computer program 3032 is executed by the processor 302, the processor 302 can execute a method for calculating the stator resistance value.

[0116] This interface 305 is used for communication with other devices. Those skilled in the art will understand that... Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the motor 300 to which the present application is applied. The specific motor 300 may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0117] It should be understood that in the embodiments of this application, the processor 302 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (FSPs), application-specific integrated circuits (ASICs), off-the-shelf programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0118] It will be understood by those skilled in the art that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program may be stored in a storage medium, which is a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the process steps of the embodiments of the above methods.

[0119] Therefore, the present invention also provides a storage medium. This storage medium can be a computer-readable storage medium. The storage medium stores a computer program. When executed by a processor, the computer program implements any embodiment of the above-described method for calculating the stator resistance value.

[0120] The storage medium can be any computer-readable storage medium capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), magnetic disk, or optical disk.

[0121] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0122] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0123] The steps in the method of this invention can be adjusted, merged, or reduced in order according to actual needs. The units in the device of this invention can be merged, divided, or reduced according to actual needs. Furthermore, the functional units in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0124] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part 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 motor to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0125] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0126] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0127] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the stator resistance value, characterized in that, Applied to an electric motor, the method includes: When the motor is stationary, a d-axis reference current is injected into the d-axis of the motor and a q-axis reference current is injected into the q-axis of the motor to obtain the d-axis feedback current and the d-axis reference voltage, wherein the q-axis reference current is 0. The relationship curve between the d-axis feedback current and the d-axis reference voltage is confirmed based on the d-axis feedback current and the d-axis reference voltage. Based on the relationship curve, a first calculation formula and a second calculation formula are confirmed, wherein the first calculation formula is used to calculate the resistance value of the stator resistor, and the second calculation formula is used to calculate the voltage error. The real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula are subjected to a sliding process to confirm the stator resistance value.

2. The method according to claim 1, characterized in that, The step of obtaining the d-axis feedback current includes: The d-axis reference voltage and q-axis reference voltage of the motor are obtained, and a first coordinate transformation is performed on the d-axis reference voltage and the q-axis reference voltage to obtain a first reference voltage and a second reference voltage. A drive signal is generated based on the first reference voltage and the second reference voltage, and the inverter of the motor is driven to output three-phase voltage through the drive signal; The three-phase current of the motor is obtained, and the three-phase current is transformed by a second coordinate transformation to obtain the d-axis feedback current.

3. The method according to claim 1, characterized in that, The step of obtaining the d-axis reference voltage includes: Obtain the d-axis feedback current and the d-axis reference current; The d-axis reference voltage is confirmed based on the d-axis feedback current and the d-axis reference current.

4. The method according to claim 1, characterized in that, The step of performing a sliding process on the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the stator resistance value includes: The first and second calculation formulas are subjected to a sliding process to obtain the modified first and second calculation formulas; The real-time voltage error is used to determine whether the motor has entered the saturation region. When the motor enters the saturation region, the real-time stator resistance value that meets the first preset condition is used as the stator resistance value.

5. The method according to claim 4, characterized in that, The method further includes: Confirm whether there are two consecutive windows with equal real-time voltage errors; If the real-time voltage error is equal in two consecutive windows, then the motor is confirmed to have entered the saturation region.

6. The method according to claim 4, characterized in that, The first preset conditions include: Confirm whether there are two consecutive windows with the same real-time stator resistance value; If two consecutive windows have the same real-time stator resistance value, then the real-time stator resistance value is taken as the stator resistance value.

7. The method according to claim 4, characterized in that, The first calculation formula is: The second calculation formula is: Among them, R s The real-time stator resistance value, Δu d For real-time voltage error, L is the window length of the sliding window, and i dj It is the d-axis feedback current corresponding to the j-th d-axis reference current, u j It is the d-axis reference voltage corresponding to the j-th d-axis reference current.

8. A device for calculating the value of stator resistance, characterized in that, Applied to an electric motor, the device includes: The first injection unit is used to inject a d-axis reference current into the d-axis of the motor and a q-axis reference current into the q-axis of the motor respectively when the motor is in a stationary state to obtain a d-axis feedback current and a d-axis reference voltage, wherein the q-axis reference current is 0; The first confirmation unit is used to confirm the relationship curve between the d-axis feedback current and the d-axis reference voltage based on the d-axis feedback current and the d-axis reference voltage. The second confirmation unit is used to confirm the first calculation formula and the second calculation formula based on the relationship curve, wherein the first calculation formula is used to calculate the resistance value of the stator resistor and the second calculation formula is used to calculate the voltage error. The first calculation unit is used to perform a sliding process on the real-time stator resistance value calculated by the first calculation formula and the real-time voltage error calculated by the second calculation formula to confirm the stator resistance value.

9. An electric motor, characterized in that, The motor includes a memory and a processor connected to the memory; the memory is used to store a computer program; the processor is used to run the computer program stored in the memory to perform the steps of the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, can implement the steps of the method as described in any one of claims 1-7.

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