Method and device for determining motor parameters

Abstract

The application discloses a motor parameter determination method and device, and a motor is connected to an inverter. The method comprises the following steps: acquiring dead zone compensation voltage values corresponding to three-phase driving voltages respectively; determining a dead zone compensation value of a direct axis in a rotating coordinate system according to the dead zone compensation voltage values corresponding to the three-phase driving voltages respectively; adding an injected voltage of the direct axis in the rotating coordinate system to the dead zone compensation value to obtain a target injected voltage of the direct axis; and determining motor parameters according to the target injected voltage of the direct axis. According to the embodiment of the application, the dead zone feedforward compensation can be performed, and the motor parameter identification accuracy is improved.

Description

Technical Field

[0001] This application belongs to the field of motor control, and in particular relates to a method and apparatus for determining motor parameters. Background Technology

[0002] Motor control requires precise motor parameters (such as stator resistance R, inductance Ld / Lq, etc.) to achieve high-performance control (such as high-precision torque output). Inaccurate parameters will lead to a decrease in control performance.

[0003] In practical applications, the existence of dead time (dead time refers to the delay time set when the inverter switches to prevent the upper and lower transistors from conducting at the same time) will cause changes in the input phase voltage, which in turn will cause changes in the direct axis voltage ud, resulting in a large error in the parameter identification results.

[0004] Therefore, the relevant technologies suffer from low accuracy in parameter identification. Summary of the Invention

[0005] This application provides a method and apparatus for determining motor parameters, which can perform dead-time feedforward compensation and improve the accuracy of motor parameter identification.

[0006] In a first aspect, embodiments of this application provide a method for determining motor parameters, wherein the motor is connected to an inverter, the method comprising: Obtain the three-phase drive voltage output by the inverter. The three-phase drive voltage is the three-phase voltage output by the inverter. Obtain the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages; Based on the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, determine the dead zone compensation value of the direct axis in the rotating coordinate system. The target injection voltage of the direct axis in the rotating coordinate system is obtained by adding the dead zone compensation value. The motor parameters are determined based on the target injection voltage of the direct shaft.

[0007] In one possible embodiment of the first aspect, obtaining the dead-time compensation voltage values ​​corresponding to the three-phase drive voltages respectively includes: Obtain the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, which is connected to the inverter. Based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, determine the compensation voltage value of the single-phase drive voltage in the first dead zone, where single-phase refers to any one of the three phases. Based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal, determine the compensation voltage value of the single-phase drive voltage in the second dead zone. The dead-zone compensation voltage value of the single-phase drive voltage is obtained by adding the compensation voltage value of the single-phase drive voltage in the first dead zone and the compensation voltage value of the single-phase drive voltage in the second dead zone.

[0008] In one possible embodiment of the first aspect, determining the compensation voltage value of the single-phase drive voltage in the first dead zone based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal includes: Where, Δu n1 The single-phase drive voltage is the compensation voltage value in the first dead zone, where n is 1, 2, or 3, and sign(i n ) represents the symbol information of the actual current of the single-phase drive current, u dc This is the voltage at the DC power supply terminal.

[0009] In one possible embodiment of the first aspect, determining the compensation voltage value of the single-phase drive voltage in the second dead zone based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal includes: Where, Δu n2 This is the compensation voltage value for the single-phase drive voltage in the second dead zone.

[0010] In one possible embodiment of the first aspect, determining the dead-zone compensation value of the direct axis in the rotating coordinate system based on the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages includes: Where Δud is the dead zone compensation value of the direct axis in the rotating coordinate system, Δua is the dead zone compensation voltage value of the first phase drive voltage, Δub is the dead zone compensation voltage value of the second phase drive voltage, Δuc is the dead zone compensation voltage value of the third phase drive voltage, td is the dead zone duration, Ts is the carrier period, and θ is the electrical angle.

[0011] In one possible embodiment of the first aspect, the injection voltage on the direct axis includes an AC signal.

[0012] In one possible embodiment of the first aspect, the injection voltage of the direct axis includes a small AC signal and a DC signal, and the injection voltage of the direct axis is greater than 0V.

[0013] In one possible embodiment of the first aspect, determining motor parameters based on the target injection voltage of the direct shaft includes: Obtain the actual value of the direct-axis drive current corresponding to the target injection voltage on the direct axis; The motor parameters are determined based on the target injection voltage and the actual values ​​of the direct shaft drive current.

[0014] In one possible embodiment of the first aspect, determining motor parameters based on the target injection voltage and the actual values ​​of the direct-axis drive current includes: The motor parameters are determined by using the recursive least squares method based on the actual values ​​of the target injection voltage and the direct shaft drive current.

[0015] Based on the same inventive concept, in a second aspect, embodiments of this application also provide a device for determining motor parameters, wherein the motor is connected to an inverter, and the device includes: The acquisition module is used to acquire the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, where the three-phase drive voltages are the three-phase voltages output by the inverter. The determination module is used to determine the dead zone compensation value of the direct axis in the rotating coordinate system based on the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages. The calculation module is used to add the injection voltage of the direct axis in the rotating coordinate system to the dead zone compensation value to obtain the target injection voltage of the direct axis; The determination module is also used to determine motor parameters based on the target injection voltage of the direct shaft.

[0016] Based on the same inventive concept, in a third aspect, embodiments of this application also provide a device for determining motor parameters, the device including a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, it implements the method for determining motor parameters in the first aspect, or any embodiment of the first aspect.

[0017] Based on the same inventive concept, in a fourth aspect, embodiments of this application also provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the first aspect, or the method for determining motor parameters in any embodiment of the first aspect.

[0018] Based on the same inventive concept, in a fifth aspect, embodiments of this application also provide a computer program product, wherein instructions in the computer program product, when executed by a processor of a device, enable the device to execute the method for determining motor parameters in the first aspect or any embodiment of the first aspect.

[0019] According to the method and apparatus for determining motor parameters provided in the embodiments of this application, by obtaining the dead zone compensation voltage values ​​Δua, Δub, and Δuc corresponding to the three-phase drive voltages respectively, and then determining the dead zone compensation value Δud of the direct axis in the rotating coordinate system based on the dead zone compensation voltage values ​​Δua, Δub, and Δuc corresponding to the three-phase drive voltages respectively, the dead zone compensation value Δud of the direct axis in the rotating coordinate system can be determined. Thus, dead zone feedforward compensation can be performed on the injected voltage ud of the direct axis based on Δud to obtain the target injected voltage (ud+Δud) of the direct axis. This can make the actual input value (ud+Δud) the expected value, thereby more accurately determining the motor parameters and improving the accuracy of parameter identification. Attached Figure Description

[0020] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which the same or similar reference numerals denote the same or similar features, and the drawings are not drawn to scale.

[0021] Figure 1 This is a schematic diagram of the connection relationship between the motor and the inverter provided in an embodiment of this application; Figure 2 This is an equivalent diagram of the a-arm of the inverter provided in the embodiments of this application; Figure 3 This is a diagram of the ideal switching signal and the switching signal after adding a dead zone, provided in the embodiments of this application; Figure 4 This is a flowchart illustrating a method for determining motor parameters provided in an embodiment of this application. Figure 5 This is another flowchart illustrating the method for determining motor parameters provided in the embodiments of this application; Figure 6 This is another flowchart illustrating the method for determining motor parameters provided in the embodiments of this application; Figure 7 This is another flowchart illustrating the method for determining motor parameters provided in the embodiments of this application; Figure 8 This is a schematic diagram of a method for determining motor parameters provided in an embodiment of this application; Figure 9 This is a schematic diagram of a device for determining motor parameters provided in an embodiment of this application. Detailed Implementation

[0022] The features and exemplary embodiments of various aspects of this application will now be described in detail. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain this application and are not configured to limit this application. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] Various modifications and variations can be made to this application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, this application is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the implementation methods provided in the embodiments of this application can be combined with each other without contradiction.

[0026] Before describing the technical solutions provided in the embodiments of this application, in order to facilitate understanding of the embodiments of this application, this application first specifically explains the problems existing in the related technologies: Motor control requires precise motor parameters (such as stator resistance R, inductance Ld / Lq, etc.) to achieve high-performance control (such as high-precision torque output). Inaccurate parameters will lead to a decrease in control performance.

[0027] Some related technologies use the least squares method to identify permanent magnet synchronous motor parameters online. The least squares method is widely used because of its high computational efficiency and ease of embedded implementation, but the existing mainstream solutions have three major bottlenecks: Firstly, there are defects in the signaling stimulation strategy.

[0028] The traditional least squares method uses constant values ​​ud and uq as 0 for open-loop parameter identification, which makes it impossible to detect the rate of change of current, resulting in a large error in inductor identification.

[0029] Secondly, the dead zone effect was not compensated.

[0030] Dead zone refers to the delay time set when the inverter is switched on to prevent the upper and lower transistors from conducting simultaneously.

[0031] The dead time of power devices affects the phase current change, which in turn affects the change of ud, severely impacting the identification accuracy.

[0032] For example, such as Figure 1 As shown, Figure 1 This is a schematic diagram of the connection between the motor and the inverter. The inverter is used to switch the DC power supply Udc at the DC voltage source terminal into three-phase AC power Ua, Ub and Uc to drive the motor.

[0033] Taking phase a as an example, the equivalent diagram of phase a in the inverter is as follows: Figure 2 As shown, bridge arm a includes an upper tube and a lower tube. The ideal switching signal and the switching signal after adding a dead time are illustrated in the diagram below. Figure 3 As shown, Figure 3 It shows Figure 2 Ideal transistor operation, transistor operation with dead time, phase voltage when phase current is greater than 0, and phase voltage when phase current is less than 0. (From...) Figure 2 and Figure 3 It can be seen that both the upper and lower transistors are in the off state in dead zone 1. If there were no dead zone, the upper transistor would be off and the lower transistor would be on. Therefore, due to the existence of the inverter dead zone (the dead zone refers to the delay time set when the inverter switches on to prevent the upper and lower transistors from conducting simultaneously), the input phase voltage of the motor will change, which in turn will cause the direct axis voltage ud to change, resulting in a large error in the parameter identification result.

[0034] Thirdly, zero-crossing failure—the pure AC excitation signal causes discontinuous voltage at zero crossings, leading to the failure of di / dt measurement and reduced accuracy of inductance parameter identification. This addresses the issue of low parameter identification accuracy in permanent magnet synchronous motors inherent in the traditional solution described above.

[0035] Therefore, the relevant technologies suffer from low accuracy in parameter identification.

[0036] Based on this, the method for determining motor parameters provided in the embodiments of this application... yes This method employs a Vd-axis composite injection method with bias voltage and a dead-time compensation feedforward mechanism to perform online parameter identification of the inductance and resistance of a permanent magnet synchronous motor (PMSM). Inductance parameters are identified by injecting an AC signal into the Vd-axis. A constant bias ensures that the input voltage avoids voltage distortion caused by zero-crossing. The dead-time feedforward mechanism ensures the accuracy of the input d-axis voltage. In other words, the Vd-axis composite injection method with bias voltage and the dead-time compensation feedforward mechanism guarantee the accuracy of the PMSM inductance and resistance parameter identification. The feedforward compensation is added in advance to the control signal (such as the injected voltage on the direct axis) to counteract the effects of the dead time.

[0037] The method for determining motor parameters provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0038] Figure 4 This is a schematic flowchart of a method for determining motor parameters provided in an embodiment of this application. The motor is connected to an inverter, such as... Figure 4 As shown, the method may include steps S110 to S140.

[0039] S110, obtain the dead zone compensation voltage values ​​(Δua, Δub and Δuc) corresponding to the three-phase drive voltages respectively. The three-phase drive voltages are the three-phase voltages (Ua, Ub and Uc) output by the inverter.

[0040] Specifically, to ensure that the injected voltage on the direct axis (d-axis) matches the desired value, dead-time feedforward compensation needs to be performed on the injected voltage on the direct axis (d-axis). For example, dead-time feedforward compensation can be performed on the injected voltage on the direct axis (d-axis) through steps S110 to S130. Step S110 involves obtaining the dead-time compensation voltage values ​​(Δua, Δub, and Δuc) corresponding to the three-phase voltages (Ua, Ub, and Uc) output by the inverter. Δua, Δub, and Δuc are the basis for determining the dead-time compensation value Δud of the direct axis in the rotating coordinate system.

[0041] S120, based on the dead zone compensation voltage values ​​(Δua, Δub and Δuc) corresponding to the three-phase drive voltages, determine the dead zone compensation value Δud of the direct axis in the rotating coordinate system.

[0042] For example, step S120, based on the dead-zone compensation voltage values ​​(Δua, Δub, and Δuc) corresponding to the three-phase drive voltages, determines the dead-zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system, which may include: Wherein, Δud is the dead zone compensation value of the direct axis (d-axis) in the rotating coordinate system, Δua is the dead zone compensation voltage value of the first phase drive voltage, Δub is the dead zone compensation voltage value of the second phase drive voltage, Δuc is the dead zone compensation voltage value of the third phase drive voltage, td is the dead zone duration (the dead zone durations of dead zone 1 and dead zone 2 are the same, both are td), Ts is the carrier period, and θ is the electrical angle (θ is 0).

[0043] In other words, by substituting the dead-zone compensation voltage values ​​(Δua, Δub, and Δuc) corresponding to the three-phase drive voltages into Equation 1, and setting θ to 0, the dead-zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system can be obtained. The embodiments of this application can accurately compensate for the direct-axis voltage error caused by the dead zone, ensuring that the target injected voltage is consistent with the expected value. This eliminates the interference of the dead zone on the identification of motor parameters (such as stator resistance and d / q-axis inductance) from the root cause, and can comprehensively quantify the superimposed influence of the dead zone of each phase on the direct-axis voltage, avoiding the limitations of single-phase compensation.

[0044] For example, Δua = Δua1 + Δua2, Δub = Δub1 + Δub2, Δuc = Δuc1 + Δuc2. Where Δua1 is the dead zone 1 of phase a (see [reference needed]). Figure 3 The compensation value is Δua2, which is the dead zone 2 of phase a (see [reference]). Figure 3 The compensation values ​​are: Δub1 is the compensation value for dead zone 1 of phase b, Δub2 is the compensation value for dead zone 2 of phase b, Δuc1 is the compensation value for dead zone 1 of phase c, and Δuc2 is the compensation value for dead zone 2 of phase c. Substituting Δua=Δua1+Δua2, Δub=Δub1+Δub2, and Δuc=Δuc1+Δuc2 into Formula 1, we can obtain the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system. By compensating the injected voltage of the direct axis (d-axis) through Δud, both dead zone 1 and dead zone 2 can be compensated.

[0045] S130, add the injection voltage ud of the direct axis (d-axis) in the rotating coordinate system to the dead zone compensation value Δud to obtain the target injection voltage (ud+Δud) of the direct axis (d-axis).

[0046] The rotating coordinate system includes a direct axis (denoted as the d-axis) and a cross axis (denoted as the q-axis), which correspond to the control of magnetic flux and torque, respectively. The term "cross" originates from its geometric relationship of being "orthogonal (perpendicular)" to the direct axis.

[0047] The target injection voltage on the direct axis (d-axis) is the input (ud+Δud) after dead-time feedforward compensation, which is consistent with the expected value.

[0048] Specifically, after determining the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system, the injection voltage ud of the direct axis (d-axis) in the rotating coordinate system can be compensated based on Δud to obtain the target injection voltage (ud+Δud) of the direct axis (d-axis), which is consistent with the expected value.

[0049] S140 determines the motor parameters based on the target injection voltage of the direct axis (d-axis).

[0050] Specifically, after calculating the target injection voltage of the direct axis (d-axis) that matches the expected value, a PWM signal corresponding to the target injection voltage can be generated based on the PWM generation module. The PWM signal can drive the switching transistors in the inverter to turn on or off at the appropriate times. Then, the actual value of the direct axis (d-axis) drive current corresponding to the target injection voltage of the direct axis (d-axis) can be obtained, and the resistance and inductance values ​​of the motor can be determined using the recursive least squares method based on the target injection voltage of the direct axis (d-axis) and the actual value of the direct axis (d-axis) drive current.

[0051] According to the method for determining motor parameters provided in the embodiments of this application, by obtaining the dead zone compensation voltage values ​​Δua, Δub, and Δuc corresponding to the three-phase drive voltages respectively, and then determining the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system based on the dead zone compensation voltage values ​​Δua, Δub, and Δuc respectively, the dead zone compensation value Δud of the direct axis (d-axis) can be determined. Thus, dead zone feedforward compensation can be performed on the injected voltage ud of the direct axis (d-axis) based on Δud to obtain the target injected voltage (ud+Δud) of the direct axis (d-axis). This can make the actual input value (ud+Δud) the expected value, thereby determining the motor parameters more accurately and improving the accuracy of parameter identification.

[0052] The following describes the specific process of dead zone feedforward compensation in the method for determining motor parameters provided in the embodiments of this application.

[0053] In some embodiments, such as Figure 5 As shown, step S110 obtains the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages, which may include steps S111 to S114. Steps S111 to S114 define the rules for determining the dead-zone compensation voltage value of each phase drive voltage.

[0054] S111: Obtain the symbol information of the actual current of the single-phase drive current and the voltage Udc of the DC power supply terminal. The DC power supply terminal is connected to the inverter.

[0055] S112, based on the sign information of the actual single-phase drive current and the voltage Udc at the DC power supply terminal, determine the compensation voltage value Δu of the single-phase drive voltage in the first dead zone. n1 In this context, a single phase is any one of the three phases.

[0056] Among them, the first dead zone is Figure 3 Dead zone 1, the second dead zone is Figure 3 Dead zone 2 in the middle.

[0057] In one example, the inventors discovered through research that the voltage variation in dead zone 1 is shown in Table 1.

[0058] Table 1 Therefore, step S112, based on the sign information of the actual single-phase drive current and the voltage Udc at the DC power supply terminal, determines the compensation voltage value of the single-phase drive voltage in the first dead zone, which may include: Where, Δu n1 The single-phase drive voltage is the compensation voltage value in the first dead zone, where n is 1, 2, or 3, and sign(i n ) represents the symbol information of the actual current of the single-phase drive current, u dcThis refers to the voltage at the DC power supply terminal. The embodiments of this application reveal the dynamic change law of the phase voltage with the sign of the current in dead zone 1 through a table-based direct representation. Based on this, a compensation voltage formula for the single-phase drive voltage in the first dead zone (dead zone 1) is derived, achieving precise quantification of the compensation value: when the sign of the current changes, the compensation value is automatically adjusted in the opposite direction to offset the voltage deviation caused by the dead zone, thereby ensuring that the direct-axis target injection voltage (ud+Δud) is strictly consistent with the expected value. This fundamentally eliminates the interference of the dead zone on the identification of motor parameters (such as stator resistance and d / q-axis inductance), significantly improving the accuracy and reliability of parameter identification. Furthermore, the formula is concise and has a clear physical meaning, facilitating real-time calculation and engineering implementation in embedded systems.

[0059] S113, based on the sign information of the actual single-phase drive current and the voltage Udc at the DC power supply terminal, determine the compensation voltage value Δu of the single-phase drive voltage in the second dead zone (dead zone 2). n2 .

[0060] In one example, the inventors discovered through research that the voltage variation in dead zone 2 is shown in Table 2.

[0061] Table 2 Therefore, step S113, based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal, determines the compensation voltage value of the single-phase drive voltage in the second dead zone (dead zone 2), which may include: Where, Δu n2 This is the compensation voltage value of the single-phase drive voltage in the second dead zone (dead zone 2). Table 2 in this application intuitively reveals the dynamic change law of the phase voltage with the current sign in dead zone 2. Based on this, the compensation voltage formula for the single-phase drive voltage in the second dead zone (dead zone 2) is derived, achieving precise quantification of the compensation value: when the current sign changes, the compensation value automatically adjusts in the opposite direction to offset the voltage offset caused by the dead zone, thereby ensuring that the direct-axis target injection voltage (ud+Δud) is strictly consistent with the expected value. This fundamentally eliminates the interference of the dead zone on the identification of motor parameters (such as stator resistance and d / q-axis inductance), significantly improving the accuracy and reliability of parameter identification. Furthermore, the formula is concise and has a clear physical meaning, facilitating real-time calculation and engineering implementation in embedded systems.

[0062] S114, the compensation voltage value Δu of the single-phase drive voltage in the first dead zone (dead zone 1) is... n1 The compensation voltage value Δu of the single-phase drive voltage in the second dead zone (dead zone 2) n2 Adding them together, we obtain the dead-time compensation voltage value Δu of the single-phase drive voltage. n Where n can take the values ​​a, b, or c.

[0063] For example, Δua = Δua1 + Δua2, Δub = Δub1 + Δub2, Δuc = Δuc1 + Δuc2. Where Δua1 is the dead zone 1 of phase a (see [reference needed]). Figure 3 The compensation value is Δua2, which is the dead zone 2 of phase a (see [reference]). Figure 3 The compensation values ​​are: Δub1 is the compensation value for dead zone 1 of phase b, Δub2 is the compensation value for dead zone 2 of phase b, Δuc1 is the compensation value for dead zone 1 of phase c, and Δuc2 is the compensation value for dead zone 2 of phase c. Substituting Δua=Δua1+Δua2, Δub=Δub1+Δub2, and Δuc=Δuc1+Δuc2 into Formula 1, we can obtain the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system. By compensating the injected voltage of the direct axis (d-axis) through Δud, both dead zone 1 and dead zone 2 can be compensated.

[0064] This application first accurately quantifies the compensation voltages (Δun1, Δun2, n taking values ​​a, b, c) for dead zone 1 (Table 1 rule) and dead zone 2 (Table 2 rule) based on the single-phase current sign and DC voltage (Udc), enabling automatic reverse adjustment of the compensation value to offset voltage deviation when the current direction changes. Then, the single-phase two dead zone compensation values ​​are superimposed to obtain the three-phase total compensation (Δua, Δub, Δuc), which can finally be integrated into the direct-axis dead zone compensation value (Δud) using Formula 1. This eliminates the interference of dead zone on motor parameter (such as stator resistance, d / q-axis inductance) identification from the root, significantly improving accuracy and reliability. Simultaneously, the formula is concise, with clear physical meaning, facilitating real-time calculation in embedded systems, and is engineering-friendly, balancing compensation accuracy and computational efficiency.

[0065] In one example, the reasoning process for the dead zone compensation value Δud of the direct axis (d-axis) in the rotated coordinate system is as follows: 1) The relationship between the d-axis input voltage ud and the phase voltage in the rotating coordinate system.

[0066] In practical applications, the existence of dead time causes changes in the input phase voltage, which in turn leads to changes in ud, resulting in a large error in the identification result. To ensure that the actual input value ud is the expected value, ud needs to be compensated.

[0067] According to the Park transformation matrix, the relationship between the d-axis input voltage ud and the phase voltage in the rotating coordinate system is as follows: According to the formula, ud is related to the phase voltage and electrical angle. Under open-loop identification, the electrical angle is always 0, so we only need to consider the relationship between ud and phase voltage.

[0068] 2) The relationship between “the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system” and “the compensation voltage values ​​(Δua, Δub and Δuc) of the single-phase drive voltage”.

[0069] Taking phase a bridge arm as an example, please refer to... Figure 2 (Equivalent diagram of phase a bridge arm) Figure 3 (Ideal switching signal and switching signal after adding dead time diagram), Table 1 and Table 2 above. Table 1 and Table 2 show the voltage changes before and after adding dead time. Table 1 shows the current and terminal voltage in dead time 1, and Table 2 shows the current and terminal voltage in dead time 2.

[0070] Combination Figure 2 Equivalent diagram of bridge arm A and Figure 3 As can be seen from the switching signal diagram before and after the addition of the dead zone, both the upper and lower transistors are in the off state in dead zone 1. If there is no dead zone, the upper transistor is off and the lower transistor is on. At this time, it is necessary to analyze the change of the lower phase voltage with or without the dead zone.

[0071] Combination Figure 2 When there is no dead zone, the phase voltage in dead zone 1 is always 0; when there is a dead zone, if the phase current is greater than 0, the phase voltage is 0; if the phase current is less than 0, the phase voltage is udc; therefore, the change of phase voltage with dead zone compared to without dead zone is shown in Table 1 above.

[0072] The analysis method for dead zone 2 is the same as that for dead zone 1, and the above Table 2 can be obtained.

[0073] Based on the dead zone compensation formulas obtained from Tables 1 and 2, the input ud can be compensated.

[0074] Therefore, the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system is: Where td is the dead time and Ts is the carrier period. As can be seen from the above formula, the compensation value is related to the phase current direction, dead time, and angle.

[0075] The compensated input ud is consistent with the expected value.

[0076] This application, based on the dynamic changes in phase voltages of dead zones 1 and 2 (Tables 1 and 2), scientifically derives the expression for the direct-axis dead-zone compensation value Δud. This expression is correlated with the phase current direction, dead-zone time, carrier period, and electrical angle, achieving a precise quantitative conversion from single-phase voltage error to total direct-axis compensation. This not only theoretically eliminates the interference of the dead zone on ud (ensuring strict consistency between the target injected voltage and the expected value), but also dynamically adapts to different operating conditions through explicit parameter relationships (such as td, Ts, and θ), significantly improving the accuracy and reliability of motor parameter (such as stator resistance and d / q-axis inductance) identification. Furthermore, the derivation logic is clear, and the formula is concise, facilitating real-time calculation and engineering implementation in embedded systems, thus balancing scientific rigor and practicality.

[0077] The following describes the specific process of determining motor parameters by inputting an AC signal to identify inductance and avoiding the zero-crossing point of the AC signal in the method provided in the embodiments of this application.

[0078] It should be noted that, according to the inventor's research, inductance identification requires an input AC signal. In order to avoid the zero-crossing point of the AC signal, the input ud is a small AC signal plus constant compensation.

[0079] In some embodiments, the injected voltage ud of the direct axis (d-axis) includes an AC signal.

[0080] This can be simply understood as AC being used to measure inductance. For example, ud = 0.2sint.

[0081] This application embodiment introduces an AC signal into the voltage ud injected into the direct axis (d-axis) (which can be simply understood as the expression of ud being in AC form), which can effectively stimulate the inductance characteristics (using the current change rate di / dt generated by the AC signal), enabling the motor inductance parameters to be accurately measured and identified, thereby improving the sensitivity and accuracy of inductance identification.

[0082] For example, the injection voltage ud of the direct axis (d-axis) includes a small AC signal and a DC signal, and the injection voltage of the direct axis (d-axis) is greater than 0V.

[0083] This can be simply understood as DC signal being used to eliminate zero-crossing points. For example, ud = 0.2sint + a. Since inductor identification requires an AC signal input, and to avoid zero-crossing points of the AC signal, the input ud is a small AC signal with constant compensation.

[0084] In this embodiment, the injection voltage ud of the direct axis (d-axis) is a superposition of a small AC signal and a DC signal, and is greater than 0V. The small AC signal component meets the inductance identification requirements and provides a basis for accurate identification of inductance parameters; the addition of the DC signal can effectively avoid the situation where the AC signal crosses zero. This injection voltage form, which combines a small AC signal with constant compensation, ensures the stability and accuracy of the inductance identification process.

[0085] In some embodiments, such as Figure 6 As shown, step S130 determines the motor parameters based on the target injection voltage of the direct axis (d-axis), and may include steps S131 and S132: S131, obtain the actual value of the direct axis (d-axis) drive current corresponding to the target injection voltage of the direct axis (d-axis); S132, determine the motor parameters based on the target injection voltage of the direct axis (d-axis) and the actual values ​​of the direct axis (d-axis) drive current.

[0086] For example, such as Figure 7 As shown, step S132 determines the motor parameters based on the target injection voltage of the direct axis (d-axis) and the actual values ​​of the direct axis (d-axis) drive current, and may include step S1321: S1321 uses the recursive least squares method to determine the motor parameters based on the target injection voltage of the direct axis (d-axis) and the actual values ​​of the direct axis (d-axis) drive current.

[0087] For example, the specific process for determining motor parameters is as follows: 1) Least squares expression.

[0088] The least squares method is widely used in practical engineering due to its simplicity and practicality. Considering the latency of online computation, the recursive least squares method, which has a smaller computational load, is selected. At the same time, in order to eliminate the possible data saturation phenomenon, a weighting function is introduced to reduce the influence of historical data.

[0089] Let the system equation at time (k+1)Ts be: y(k+1) is obtained through measurement. The value of is then used to estimate the parameter sequence. The value of .

[0090] The least squares method expression is given below: Where λ∈(0,1] is the weighting value, which is 1 in this paper; the initial value P(0) is a diagonal matrix of 0.4. These are the parameter estimates from the previous time step. It is the prediction of the output value at this moment, while y(k+1) is the actual output value at this moment. This refers to the prediction error. Due to the existence of error, the estimated value of the parameter sequence at this moment is... The estimated value from the previous time step needs to be corrected based on the prediction error, and the correction gain is L(k+1).

[0091] 2) Represent ud using a small AC signal plus constant compensation. For example, ud = 0.2sint + a.

[0092] Since inductor identification requires an AC signal input, and to avoid the AC signal crossing zero, the input ud is a small AC signal plus constant compensation.

[0093] 3) Calculate the dead zone compensation value Δud of the direct axis (d-axis) in the rotating coordinate system.

[0094] 4) Add ud and Δud to obtain the target injection voltage (ud+Δud) on the direct axis (d-axis).

[0095] 5) Obtain the actual value of the direct axis (d-axis) drive current corresponding to the target injection voltage of the direct axis (d-axis); use the recursive least squares method to determine the motor parameters based on the target injection voltage of the direct axis (d-axis) and the actual value of the direct axis (d-axis) drive current.

[0096] For ease of controller design, a mathematical model in a synchronous rotating coordinate system is usually chosen, and its d-axis voltage dynamic equation is as follows: Where ud is the d-axis component of the stator voltage; id and iq are the dq-axis components of the stator current, respectively; R is the stator resistance; and Ld and Lq are the dq-axis inductance components, respectively. ω is the electric angular velocity.

[0097] The discrete form of the above equation is: When the open loop uses ud as input, then Combining this with the least squares expression, we can obtain: Adding the d-axis input voltage ud in the above equation to the dead-zone compensation value derived in this paper, we get: By substituting the above equation into the least squares expression and iterating, the resistance and inductance values ​​of the surface-mounted permanent magnet synchronous motor can be identified with high precision.

[0098] This application provides an online parameter identification method for permanent magnet synchronous motors based on the Vd-axis composite injection method with dead-zone feedforward compensation using bias voltage. Considering the impact of dead zone on resistance and inductance identification, the changes in input voltage before and after adding dead zone are analyzed in detail, and a dead-zone compensation formula is given. Addressing the physical nature that inductance parameter identification must rely on the rate of change of current (di / dt), a constant bias is superimposed with an AC signal in the relevant power frequency band to achieve high-precision parameter identification of the resistance and inductance of the surface-mounted permanent magnet synchronous motor.

[0099] Based on the same inventive concept, such as Figure 8 As shown in the embodiment of this application, a device for determining motor parameters is also provided. This device 800 may include an acquisition module 810, a determination module 820, and a calculation module 830. The acquisition module 810 is used to acquire the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, where the three-phase drive voltages are the three-phase voltages output by the inverter. The determination module 820 is used to determine the dead zone compensation value of the direct axis in the rotating coordinate system based on the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages. The calculation module 830 is used to add the injection voltage of the direct axis in the rotating coordinate system to the dead zone compensation value to obtain the target injection voltage of the direct axis; The determination module 820 is also used to determine motor parameters based on the target injection voltage of the direct shaft.

[0100] According to the motor parameter determination device provided in the embodiments of this application, by acquiring the dead zone compensation voltage values ​​Δua, Δub, and Δuc corresponding to the three-phase drive voltages respectively, and then determining the dead zone compensation value Δud of the direct axis in the rotating coordinate system based on the dead zone compensation voltage values ​​Δua, Δub, and Δuc corresponding to the three-phase drive voltages respectively, the dead zone compensation value Δud of the direct axis in the rotating coordinate system can be determined. Thus, dead zone feedforward compensation can be performed on the injected voltage ud of the direct axis based on Δud to obtain the target injected voltage (ud+Δud) of the direct axis. This can make the actual input value (ud+Δud) the expected value, thereby determining the motor parameters more accurately and improving the accuracy of parameter identification.

[0101] In some embodiments, the acquisition module is used to acquire the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages, specifically for: Obtain the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, which is connected to the inverter. Based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, determine the compensation voltage value of the single-phase drive voltage in the first dead zone, where single-phase refers to any one of the three phases. Based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal, determine the compensation voltage value of the single-phase drive voltage in the second dead zone. The dead-zone compensation voltage value of the single-phase drive voltage is obtained by adding the compensation voltage value of the single-phase drive voltage in the first dead zone and the compensation voltage value of the single-phase drive voltage in the second dead zone.

[0102] In some embodiments, the determining module is used to determine the compensation voltage value of the single-phase drive voltage in the first dead zone based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal. Specifically, it can be used for: Where, Δu n1 The single-phase drive voltage is the compensation voltage value in the first dead zone, where n is 1, 2, or 3, and sign(i n ) represents the symbol information of the actual current of the single-phase drive current, u dc This is the voltage at the DC power supply terminal.

[0103] In some embodiments, the determining module is used to determine the compensation voltage value of the single-phase drive voltage in the second dead zone based on the sign information of the actual single-phase drive current and the voltage at the DC power supply terminal. Specifically, it can be used for: Where, Δu n2 This is the compensation voltage value for the single-phase drive voltage in the second dead zone.

[0104] In some embodiments, the determining module is used to determine the dead-zone compensation value of the direct axis in the rotating coordinate system based on the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages, specifically for: Where Δud is the dead zone compensation value of the direct axis in the rotating coordinate system, Δua is the dead zone compensation voltage value of the first phase drive voltage, Δub is the dead zone compensation voltage value of the second phase drive voltage, Δuc is the dead zone compensation voltage value of the third phase drive voltage, td is the dead zone duration, Ts is the carrier period, and θ is the electrical angle.

[0105] In some embodiments, the injection voltage along the direct axis includes an AC signal.

[0106] In some embodiments, the injection voltage of the direct axis includes a small AC signal and a DC signal, and the injection voltage of the direct axis is greater than 0V.

[0107] In some embodiments, the determining module is used to determine motor parameters based on the target injection voltage of the direct shaft, specifically for: Obtain the actual value of the direct-axis drive current corresponding to the target injection voltage on the direct axis; The motor parameters are determined based on the target injection voltage and the actual values ​​of the direct shaft drive current.

[0108] In some embodiments, the determining module is used to determine motor parameters based on the actual values ​​of the target injection voltage and the direct-axis drive current, specifically for: The motor parameters are determined by using the recursive least squares method based on the actual values ​​of the target injection voltage and the direct shaft drive current.

[0109] The various modules in the motor parameter determination device provided in this application embodiment can achieve... Figures 1 to 7 The functions of each step in the method for determining motor parameters, and the corresponding technical effects they achieve, will not be elaborated here for the sake of brevity.

[0110] Figure 9 A schematic diagram of the hardware structure of the device for determining motor parameters provided in an embodiment of this application is shown.

[0111] The device for determining motor parameters may include a processor 901 and a memory 902 storing computer program instructions.

[0112] Specifically, the processor 901 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0113] Memory 902 may include mass storage for data or instructions. For example, and not limitingly, memory 902 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where suitable, memory 902 may include removable or non-removable (or fixed) media. Where suitable, memory 902 may be internal or external to a device for determining motor parameters. In a particular embodiment, memory 902 is a non-volatile solid-state memory.

[0114] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to one aspect of this disclosure.

[0115] The processor 901 reads and executes computer program instructions stored in the memory 902 to implement any of the methods for determining motor parameters in the above embodiments.

[0116] In one example, the device for determining motor parameters may also include a communication interface 903 and a bus 904. For example, Figure 9 As shown, the processor 901, memory 902, and communication interface 903 are connected through bus 904 and complete communication with each other.

[0117] The communication interface 903 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0118] Bus 904 includes hardware, software, or both, that couples components of a device that determines motor parameters together. For example, and not limited to, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Linear Predictive Coding (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (Peripheral Component Interconnect-X, PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VESA LocalBus, VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 904 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, this application contemplates any suitable bus or interconnection.

[0119] This device can execute the motor parameter determination method in the embodiments of this application based on each unit / component in the motor parameter determination device, thereby achieving a combination Figures 1 to 7 The method for determining the motor parameters is described.

[0120] Furthermore, in conjunction with the motor parameter determination methods in the above embodiments, this application embodiment can provide a computer storage medium for implementation. This computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the motor parameter determination methods in the above embodiments.

[0121] This application also provides a computer program product, wherein the instructions in the computer program product, when executed by the processor of an electronic device, cause the electronic device to perform various processes implementing any of the above-described embodiments of the method for determining motor parameters.

[0122] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0123] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, read-only memory (ROM), flash memory, erasable read-only memory (EROM), floppy disks, compact disc read-only memory (CD-ROM), optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0124] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0125] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0126] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application 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 this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method of determining parameters of an electrical machine, characterized in that, The motor is connected to the inverter, and the method includes: Obtain the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, wherein the three-phase drive voltages are the three-phase voltages output by the inverter; Based on the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, determine the dead zone compensation value of the direct axis in the rotating coordinate system. The target injection voltage of the direct axis in the rotating coordinate system is obtained by adding the dead zone compensation value. The motor parameters are determined based on the target injection voltage of the straight shaft.

2. The method of claim 1, wherein, The step of obtaining the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages includes: Obtain the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, which is connected to the inverter; Based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, the compensation voltage value of the single-phase drive voltage in the first dead zone is determined, wherein the single phase is any one of the three phases; Based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal, determine the compensation voltage value of the single-phase drive voltage in the second dead zone. The dead-zone compensation voltage value of the single-phase drive voltage is obtained by adding the compensation voltage value of the single-phase drive voltage in the first dead zone and the compensation voltage value of the single-phase drive voltage in the second dead zone.

3. The method of claim 2, wherein, The step of determining the compensation voltage value of the single-phase drive voltage in the first dead zone based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal includes: Wherein, the Δu n1 is the compensation voltage value of the single-phase driving voltage in the first dead zone, the n is 1, 2, or 3, the sign(i n ) is the sign information of the actual current of the single-phase driving current, the u dc is the voltage of the direct current power supply end.

4. The method of claim 3, wherein, The step of determining the compensation voltage value of the single-phase drive voltage in the second dead zone based on the sign information of the actual current of the single-phase drive current and the voltage at the DC power supply terminal includes: Wherein, the Δu n2 is the compensation voltage value of the single-phase driving voltage in the second dead zone.

5. The method according to any one of claims 1 to 4, characterized in that, The step of determining the dead-zone compensation value of the direct axis in the rotating coordinate system based on the dead-zone compensation voltage values ​​corresponding to the three-phase drive voltages includes: Where Δud is the dead zone compensation value of the direct axis in the rotating coordinate system, Δua is the dead zone compensation voltage value of the first phase drive voltage, Δub is the dead zone compensation voltage value of the second phase drive voltage, Δuc is the dead zone compensation voltage value of the third phase drive voltage, td is the dead zone duration, Ts is the carrier period, and θ is the electrical angle.

6. The method of claim 1, wherein, The injected voltage on the direct axis includes an AC signal.

7. The method of claim 6, wherein, The injection voltage of the direct axis includes a small AC signal and a DC signal, and the injection voltage of the direct axis is greater than 0V.

8. The method of claim 1, wherein, The step of determining the motor parameters based on the target injection voltage of the direct shaft includes: Obtain the actual value of the direct-axis drive current corresponding to the target injection voltage of the direct axis; The motor parameters are determined based on the target injection voltage of the direct shaft and the actual value of the direct shaft drive current.

9. The method of claim 8, wherein, The process of determining motor parameters based on the target injection voltage of the direct shaft and the actual values ​​of the direct shaft drive current includes: The motor parameters are determined using the recursive least squares method based on the target injection voltage of the direct shaft and the actual value of the direct shaft drive current.

10. An apparatus for determining parameters of an electrical machine, characterized by The motor is connected to the inverter, and the device includes: The acquisition module is used to acquire the dead zone compensation voltage values ​​corresponding to the three-phase drive voltages, wherein the three-phase drive voltages are the three-phase voltages output by the inverter; The determining module is configured to determine a dead-time compensation value of a direct axis in a rotating coordinate system according to a dead-time compensation voltage value corresponding to the three-phase driving voltage; and add the injection voltage of the direct axis in the rotating coordinate system to the dead-time compensation value to obtain a target injection voltage of the direct axis. The determining module is further configured to determine the motor parameter according to the target injection voltage of the direct axis.

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