Permanent magnet synchronous motor d-axis forward judgment method, electronic equipment and medium

Abstract

The invention discloses a permanent magnet synchronous motor d-axis forward judgment method, electronic equipment and a medium. The method comprises the steps of constructing an estimation dq coordinate system, determining an estimation d-axis positive direction, inputting high-frequency cosine voltage to a d axis of the permanent magnet synchronous motor, and waiting for position convergence of the permanent magnet synchronous motor; after the position of the permanent magnet synchronous motor converges, current is input to the q axis of the permanent magnet synchronous motor, and the rotation direction of a rotor is obtained; and determining the d-axis positive direction according to the rotor rotation direction. In this way, the d-axis positive direction of the permanent magnet synchronous motor can be rapidly and accurately judged.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a method for determining the positive direction of the d-axis of a permanent magnet synchronous motor, an electronic device, and a medium. Background Art

[0002] Permanent magnet synchronous motors are widely used due to their high power and high efficiency. They are usually divided into three types: surface mount and embedded. Vector control technology can enable permanent magnet synchronous motors to achieve good operating performance, and its control process requires rotor position information. Since mechanical position sensors have problems such as large size and weight, high cost, inconvenient installation, and poor accuracy in special occasions, sensorless control technology has received widespread attention. How to use sensorless technology to estimate the position of permanent magnet motors has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] The present application provides a method for determining the positive direction of the d-axis of a permanent magnet synchronous motor, an electronic device, and a medium, which can determine the positive direction of the d-axis of the permanent magnet synchronous motor.

[0004] The first technical solution adopted in the present application is: to provide a method for determining the positive direction of the d-axis of a permanent magnet synchronous motor. The method includes constructing an estimated dq coordinate system to determine the estimated positive direction of the d-axis; inputting a high-frequency cosine voltage to the d-axis of the permanent magnet synchronous motor, waiting for the rotor position in the permanent magnet synchronous motor to converge, and obtaining the estimated positive direction of the d-axis of the permanent magnet synchronous motor; after the rotor position in the permanent magnet synchronous motor converges, inputting a current to the q-axis of the permanent magnet synchronous motor to obtain the direction of rotation of the rotor; and determining the positive direction of the d-axis according to the direction of rotation of the rotor and the estimated positive direction of the d-axis.

[0005] Among them, determining the positive direction of the d-axis according to the rotor rotation direction and the estimated positive direction of the d-axis includes: in response to the rotor rotation direction being forward rotation, determining the estimated positive direction of the d-axis as the positive direction of the d-axis; in response to the rotor direction being reverse rotation, determining the estimated positive direction of the d-axis as the negative direction of the d-axis.

[0006] Among them, determining the positive direction of the d-axis according to the rotor rotation direction and the estimated positive direction of the d-axis includes: obtaining the q-axis feedback current and the rotor feedback speed, wherein the rotor feedback speed is a positive speed, indicating that the rotor rotation direction is forward, and the rotor feedback speed is a negative speed, indicating that the rotor rotation direction is reverse; multiplying the q-axis feedback current and the rotor feedback speed to obtain a judgment variable; in response to the judgment variable being greater than a preset positive threshold, determining that the estimated positive direction of the d-axis is the positive direction of the d-axis, and in response to the judgment variable being less than a preset negative threshold, determining that the estimated positive direction of the d-axis is the negative direction of the d-axis.

[0007] Among them, obtaining the q-axis feedback current and the rotor feedback speed includes: obtaining multiple groups of feedback information, each group of feedback information includes a q-axis feedback current and a rotor feedback speed, and the multiple groups of feedback information are obtained by correspondingly inputting multiple groups of currents with the same direction and different sizes to the q-axis; multiplying the q-axis feedback current by the rotor feedback speed to obtain a judgment variable, including: multiplying the q-axis feedback current by the rotor feedback speed in each group to obtain multiple groups of judgment variables; in response to the judgment variable being greater than a preset positive threshold, determining that the estimated positive direction of the d-axis is the positive direction of the d-axis, and in response to the judgment variable being less than a preset negative threshold, determining that the estimated positive direction of the d-axis is the negative direction of the d-axis, including: judging the multiple groups of judgment variables, in response to the judgment variable being greater than the preset positive threshold for a number of times exceeding the preset number of times, determining that the estimated positive direction of the d-axis is the positive direction of the d-axis, and in response to the judgment variable being less than the preset negative threshold for a number of times exceeding the preset number of times, determining that the estimated positive direction of the d-axis is the negative direction of the d-axis.

[0008] Wherein, inputting current into the q-axis of the permanent magnet synchronous motor includes: inputting current that increases with time into the q-axis of the permanent magnet synchronous motor.

[0009] The rate at which the current value of the current input to the q-axis increases over time is a preset value.

[0010] The current input to the q-axis of the permanent magnet synchronous motor does not exceed a preset maximum current value of the frequency converter in the permanent magnet synchronous motor.

[0011] When a high-frequency cosine voltage is input to the d-axis of the permanent magnet synchronous motor, the rotor speed of the permanent magnet synchronous motor is less than a preset speed.

[0012] The second technical solution adopted by the present application is to provide an electronic device, which includes a memory and a processor, wherein the memory is used to store program data, and the program data can be executed by the processor to implement the method described in the first technical solution.

[0013] The third technical solution adopted by the present application is to provide a computer-readable storage medium, which stores program data and can be executed by a processor to implement the method described in the first technical solution.

[0014] The beneficial effects of the present application are as follows: construct an estimated dq coordinate system, determine the estimated positive direction of the d-axis, converge the rotor in the permanent magnet synchronous motor by a high-frequency injection method, then input current to the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction. Determine the actual positive direction of the d-axis of the permanent magnet synchronous motor according to the rotation direction of the rotor and the estimated positive direction of the d-axis. Since the estimated positive direction of the d-axis may coincide with the actual positive direction of the d-axis, or may be opposite to the actual positive direction of the d-axis, and after the high-frequency injection rotor converges and inputs current to the q-axis, the overlap of the two estimated positive directions of the d-axis and the actual positive direction of the d-axis will correspond to different rotor rotation directions, so according to the rotor rotation direction, it is possible to quickly and accurately determine whether the current estimated positive direction of the d-axis is the actual positive direction of the d-axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 is a principle flow chart of high frequency voltage injection used in this application;

[0017] Figure 2 This is a flow chart of the first embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application;

[0018] Figure 3 This is a flow chart of the second embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application;

[0019] Figure 4 This is a flow chart of the third embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application;

[0020] Figure 5 This is a flow chart of the fourth embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application;

[0021] Figure 6 This is a flow chart of a specific embodiment of a method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application;

[0022] Figure 7 It is a structural schematic diagram of an embodiment of the electronic device of the present application;

[0023] Figure 8 It is a structural diagram of an embodiment of a computer-readable storage medium of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] The terms "first", "second", etc. in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0026] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] Before introducing the technical solution of the present application, a brief introduction to the related technologies is first given.

[0028] Reference Figure 1 , Figure 1 This is a principle flow chart of the high frequency voltage injection used in this application.

[0029] First, construct the coordinate system. The dq coordinate system is the actual rotor synchronous rotation coordinate system. is the coordinate system for estimating the synchronous rotation of the rotor, and α-β is the actual two-phase stationary coordinate system. The position estimation error is

[0030] The high-frequency cosine voltage u is input to the d-axis of the permanent magnet synchronous motor to estimate the synchronous rotation coordinate system of the rotor. h *cos(w h t),u h is the amplitude of the high-frequency cosine voltage, t is the current moment, w h Angular frequency of high-frequency cosine voltage.

[0031] Perform an inverse Park transformation (invPark) on the voltage of the d-axis of the input estimated rotor synchronous rotating coordinate system to obtain the voltage signal u in the α-β coordinate system α and u βThen, the space vector pulse width modulator (SVPWM) is used to process the voltage signal in the α-β coordinate system to obtain six switching signals, control the three-phase full-bridge inverter (Inverter), and inject the voltage signal into the stator winding of the permanent magnet synchronous motor (SPMSM).

[0032] The three-phase current i of the motor is collected by the current sensor a 、i b andi c , Clark transformation is performed on any two phases to obtain the current signal i in the α-β coordinate system α and i β , and then through Park transformation (Park) to obtain the d-axis current response signal in the dq coordinate system and q-axis current response signal The DC component is then obtained through a low-pass filter (LPF) for closed-loop control of the current.

[0033] For the q-axis current response signal The bandpass filter (BPF) is also used to process it to obtain the high-frequency response current of the q axis. The expression is as follows:

[0034]

[0035] Among them, r diff and L diff It is the difference between the high frequency response resistance and inductance of the d-axis and q-axis.

[0036] The high frequency response current and the sinusoidal signal sin(w h t) After multiplication, low-pass filtering is performed to obtain the position estimation error signal The expression is as follows:

[0037]

[0038] PI is a proportional integral regulator, I is an integral regulator, which is used to build a position deviation closed loop to estimate the position error signal As input to the PI regulator, the estimated rotor angular velocity is the output of the regulator, and the estimated rotor angular velocity The estimated rotor position is obtained by integration, and the above steps are repeated until the estimated rotor position converges to obtain the rotor convergence position.

[0039] Park transformation is the most commonly used coordinate transformation for analyzing the operation of synchronous motors. Park transformation projects the three-phase currents a, b, and c of the stator onto the direct axis (d axis) rotating with the rotor, the quadrature axis (q axis), and the zero axis (0 axis) perpendicular to the dq plane, thereby achieving the diagonalization of the stator inductance matrix and simplifying the operation analysis of the synchronous motor.

[0040] The Clarke transform is a process of converting the time domain components of a three-phase system (in the abc coordinate system) into two components in an orthogonal stationary coordinate system (α-β).

[0041] From the above, we can see that when the position estimation error is zero, that is, when the estimated position is equal to the actual rotor position, the position estimation error signal is 0. Therefore, the closed-loop control position estimation error signal When is 0, the estimated position converges. From the above formula, it can be obtained that when the position estimation error When it is 0 or π, the low-frequency component is 0. Therefore, when converging, the convergence position of the motor rotor is in the positive direction of the d-axis or the negative direction of the d-axis.

[0042] Since there are two situations when the motor rotor converges, further judgment is needed to determine the positive direction of the d-axis of the permanent magnet synchronous motor.

[0043] In some cases, the d-axis response current injected at high frequency can be detected, and the second harmonic component of the d-axis current response can be selected by passing it through a bandpass filter, and the second harmonic component can be combined with the cosine signal cos(2w h t) multiplied by the DC component and frequency, 4w h The AC component of h The angular frequency of the high-frequency voltage is injected into the d-axis, and then the DC component is extracted using a low-pass filter. The positive direction of the rotor d-axis is then determined based on the positive or negative value of the DC component. However, in this method, the DC component of the d-axis response current is very small and close to zero, which can easily lead to misjudgment.

[0044] In some cases, the positive direction of the d-axis can be determined by injecting a high-frequency sinusoidal voltage signal and then judging the magnitude of the positive peak and negative peak of the d-axis response current. However, in this method, since the surface-mounted permanent magnet synchronous motor does not have physical salient poles, the positive peak and negative peak of the d-axis response current are similar for the surface-mounted permanent magnet synchronous motor, which places high demands on current sampling and is prone to misjudgment.

[0045] Based on this, the present application proposes a method for determining the positive direction of the d-axis of a permanent magnet synchronous motor.

[0046] Reference Figure 2 , Figure 2This is a flow chart of the first embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application, which includes but is not limited to the following steps.

[0047] S11: Construct an estimated dq coordinate system and determine the estimated positive direction of the d-axis.

[0048] An estimated dq coordinate system is constructed according to the magnetic field direction (or the direction of the magnetic flux lines) of the magnetic field that the rotor should generate when energized, and the positive direction of the d-axis is estimated to be parallel to the magnetic field direction.

[0049] S12: Input a high-frequency cosine voltage to the d-axis of the permanent magnet synchronous motor, and wait for the rotor position in the permanent magnet synchronous motor to converge.

[0050] When the rotor position converges, as described above, the rotor converges to the positive direction of the actual d-axis or the negative direction of the actual d-axis. At this time, the estimated d-axis positive direction in the constructed estimated coordinate system coincides with the actual d-axis positive direction or the actual d-axis negative direction.

[0051] The step of constructing an estimated dq coordinate system can also be performed after high frequency injection is completed and the rotor has converged. At this time, the estimated coordinate system is constructed according to the magnetic field direction of the rotor to determine the estimated positive direction of the d-axis.

[0052] S13: After the rotor position in the permanent magnet synchronous motor converges, current is input to the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction.

[0053] S14: Determine the positive direction of the d-axis according to the rotor rotation direction and the estimated positive direction of the d-axis.

[0054] After the high-frequency injection converges, when the current is injected into the q-axis, the rotor will rotate in different directions depending on the convergence position. Therefore, the rotation direction of the rotor can be used to determine whether the estimated d-axis positive direction is the actual d-axis positive direction.

[0055] In this embodiment, an estimated dq coordinate system is constructed, and after the estimated positive direction of the d-axis is determined, the rotor in the permanent magnet synchronous motor is converged by a high-frequency injection method, and then a current is input to the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction. The actual positive direction of the d-axis of the permanent magnet synchronous motor is determined according to the rotation direction of the rotor and the estimated positive direction of the d-axis. Since the estimated positive direction of the d-axis may coincide with the actual positive direction of the d-axis, or may be opposite to the actual positive direction of the d-axis, and after the high-frequency injection rotor converges and the current is input to the q-axis, the overlap of the two estimated positive directions of the d-axis and the actual positive direction of the d-axis will correspond to different rotor rotation directions, so according to the rotor rotation direction, it is possible to quickly and accurately determine whether the current estimated positive direction of the d-axis is the actual positive direction of the d-axis.

[0056] Reference Figure 3 , Figure 3This is a flow chart of the second embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application. The method is a further extension of the above embodiment, and includes but is not limited to the following steps.

[0057] S21: Construct an estimated dq coordinate system and determine the estimated positive direction of the d-axis.

[0058] S22: Input a high-frequency cosine voltage to the d-axis of the permanent magnet synchronous motor, and wait for the rotor position in the permanent magnet synchronous motor to converge.

[0059] S23: After the rotor position in the permanent magnet synchronous motor converges, current is input to the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction.

[0060] Similar steps are described with reference to the above embodiments.

[0061] S24: In response to the rotor rotating in the forward direction, the estimated d-axis positive direction is determined as the d-axis positive direction; in response to the rotor rotating in the reverse direction, the estimated d-axis positive direction is determined as the d-axis negative direction.

[0062] When judging the actual positive direction of the d-axis according to the direction of the rotor, the rotor rotation direction is determined to be forward or reverse. If it is forward, the estimated positive direction of the d-axis is the positive direction of the actual d-axis, and if it is reverse, the estimated positive direction of the d-axis is the negative direction of the actual d-axis.

[0063] The forward rotation direction of the permanent magnet synchronous motor rotor is determined during the motor design process. The forward rotation direction is determined based on multiple factors such as usage scenario, power, speed, etc. to ensure that the motor has optimal performance and efficiency under normal working conditions.

[0064] In one embodiment, the positive direction of the d-axis can also be determined by obtaining the rotor feedback speed. The rotor feedback speed is a positive speed, indicating that the rotor rotation direction is forward, and the rotor feedback speed is a negative speed, indicating that the rotor rotation direction is reverse. If the rotor feedback speed is a positive speed, the estimated positive direction of the d-axis is determined to be the positive direction of the d-axis, and if the rotor feedback speed is a negative speed, the estimated positive direction of the d-axis is determined to be the negative direction of the d-axis.

[0065] Reference Figure 4 , Figure 4 This is a flow chart of the third embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application. The method is a further extension of step S13, which includes but is not limited to the following steps.

[0066] S31: Obtaining the q-axis feedback current and the rotor feedback speed, wherein the rotor feedback speed is a positive speed, indicating that the rotor rotation direction is forward, and the rotor feedback speed is a negative speed, indicating that the rotor rotation direction is reverse.

[0067] S32: Multiply the q-axis feedback current and the rotor feedback speed to obtain a judgment variable.

[0068] S33: In response to the judgment variable being greater than a preset positive threshold, determining the estimated positive direction of the d-axis to be the positive direction of the d-axis; in response to the judgment variable being less than a preset negative threshold, determining the estimated positive direction of the d-axis to be the negative direction of the d-axis.

[0069] Since the rotor feedback speed is usually very small when the motor just starts to rotate, the q-axis feedback current is obtained at the same time when the rotor feedback current is obtained. The q-axis feedback current is multiplied by the rotor feedback speed to obtain the judgment variable, and the coincidence of the estimated d-axis positive direction and the actual d-axis positive direction is judged according to the positive and negative and size of the judgment variable. By multiplying the q-axis feedback current by the rotor feedback speed, the absolute value of the judgment variable is increased, making the variable far away from the coordinate zero point, making the judgment easier and more accurate, and avoiding judgment errors.

[0070] In this embodiment, the q-axis feedback current is only a positive current.

[0071] The absolute values ​​of the preset positive threshold value and the preset negative threshold value are equal, and their numerical values ​​are adjusted and determined based on actual factors such as the actual use scenario of the permanent magnet synchronous motor and the q-axis input current size, and are not limited here.

[0072] Reference Figure 5 , Figure 5 This is a flow chart of a fourth embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application. The method is a further extension of the above embodiment, and includes but is not limited to the following steps.

[0073] S41: Acquire multiple sets of feedback information, each set of feedback information includes a q-axis feedback current and a rotor feedback speed, and the multiple sets of feedback information are obtained by correspondingly inputting multiple sets of currents with the same direction and different magnitudes to the q-axis.

[0074] This step is a further extension of step S31. Multiple sets of feedback information are obtained to determine the acquisition of variables. For example, for multiple sets of currents A, B, C, etc. with the same q-axis input direction and different magnitudes, the corresponding q-axis feedback currents a, b, c, etc. are obtained, and the corresponding rotor feedback speeds are a1, b1, c1, etc. The feedback current and the corresponding rotor feedback speed are a set of feedback information, that is, a and a1 are a set of feedback information.

[0075] S42: Multiply the q-axis feedback current and the rotor feedback speed in each group to obtain multiple groups of judgment variables.

[0076] This step is a further extension of step S32. Each set of feedback information is calculated to obtain respective judgment variables.

[0077] S43: Judge multiple groups of judgment variables, and in response to the judgment variable being greater than a preset positive threshold for more than a preset number of times, determine that the estimated positive direction of the d-axis is the positive direction of the d-axis; in response to the judgment variable being less than a preset negative threshold for more than a preset number of times, determine that the estimated positive direction of the d-axis is the negative direction of the d-axis.

[0078] This step is a further extension of step S33. In order to ensure the accuracy of the judgment, if there are more than a preset number of judgments that the estimated positive direction of the d-axis is the positive direction of the d-axis, then the estimated positive direction of the d-axis is finally determined to be the positive direction of the d-axis; if there are more than a preset number of judgments that the estimated positive direction of the d-axis is the negative direction of the d-axis, then the estimated positive direction of the d-axis is finally determined to be the negative direction of the d-axis.

[0079] In some embodiments, inputting a current into the q-axis of the permanent magnet synchronous motor includes: inputting a current that increases over time into the q-axis of the permanent magnet synchronous motor.

[0080] Further, in some embodiments, the current value of the current initially input to the q-axis of the permanent magnet synchronous motor is less than a preset current value.

[0081] This is to protect the synchronous motor while determining the positive direction of the motor rotor D axis. A gradually increasing current is input to the electron to avoid suddenly inputting a large current value to the rotor, which may cause damage to the electrode.

[0082] In some embodiments, the rate at which the current value of the input q-axis current increases over time is a preset value. Similar to the above embodiment, the q-axis input current is increased with a fixed slope so that the current input to the motor is a steadily increasing current, which is also to protect the motor and avoid damaging the motor.

[0083] In some embodiments, the current input to the q-axis of the permanent magnet synchronous motor does not exceed the preset maximum current value of the frequency converter in the permanent magnet synchronous motor. The maximum value is set for the input current to avoid damage to the motor, thereby affecting the judgment result.

[0084] In some embodiments, when a high-frequency cosine voltage is input to the d-axis of the permanent magnet synchronous motor, the rotor speed of the permanent magnet synchronous motor is less than a preset speed. Since the position convergence of the rotor can be achieved by the high-frequency injection method when the permanent magnet synchronous motor is at zero speed or low speed, but the position convergence of the rotor may not be achieved when the permanent magnet synchronous motor rotates at high speed, when the high-frequency injection method is performed, the rotor speed of the permanent magnet synchronous motor needs to be less than the preset speed.

[0085] The following is a specific example to illustrate the present application in more detail. Figure 6 , Figure 6 This is a flow chart of a specific embodiment of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor of the present application.

[0086] After constructing an estimated dq coordinate system according to the magnetic field direction when the rotor is energized, the estimated positive direction of the d-axis is determined.

[0087] Then first, a high frequency cosine voltage is input to the d-axis.

[0088] After a waiting period, the rotor position converges, usually 5-10 milliseconds.

[0089] Then, a current increasing with a fixed slope k is input to the q-axis, and the current is limited so as not to exceed the maximum current value set by the inverter in the motor.

[0090] After the current loop is closed, the q-axis feedback current Iqfdb and the rotor feedback speed speedfdb are obtained, and the judgment variable Pfdb=Iqfdb*speedfdb is calculated in real time.

[0091] When the judgment variable Pfdb is greater than the set positive threshold PH, the count value Checkcounter increases by 1, and when the judgment variable Pfdb is less than the set negative threshold PL, the count value Checkcounter decreases by 1. The positive threshold PH is equal to the negative threshold PL in absolute value, PH=-PL.

[0092] After a period of time, when the count value Checkcounter is greater than the preset number of times Time, it is judged that the rotor convergence position is in the positive direction of the d-axis, and the positive direction of the d-axis is estimated to be the actual positive direction of the d-axis. When the count value Checkcounter is less than the negative preset number of times -Time, it is judged that the rotor convergence position is in the negative direction of the d-axis, and the positive direction of the d-axis is estimated to be the actual negative direction of the d-axis.

[0093] like Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application.

[0094] The electronic device includes a processor 110 and a memory 120 .

[0095] The processor 110 controls the operation of the electronic device, and the processor 110 may also be referred to as a CPU (Central Processing Unit). The processor 110 may be an integrated circuit chip having the ability to process a signal sequence. The processor 110 may also be a general-purpose processor, a digital signal sequence processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0096] The memory 120 stores instructions and program data required for the processor 110 to operate.

[0097] The processor 110 is used to execute instructions to implement the method provided by any embodiment and possible combination of the method for determining the positive direction of the d-axis of a permanent magnet synchronous motor described above in the present application.

[0098] like Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of an embodiment of a computer-readable storage medium of the present application.

[0099] An embodiment of a readable storage medium of the present application includes a memory 210, and the memory 210 stores program data. When the program data is executed, the method provided by any embodiment and possible combination of the permanent magnet synchronous motor d-axis positive direction judgment method of the present application is implemented.

[0100] The memory 210 may include a medium that can store program instructions, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, or it may be a server that stores the program instructions. The server may send the stored program instructions to other devices for execution, or it may execute the stored program instructions itself.

[0101] In summary, after constructing the estimated dq coordinate system and determining the estimated positive direction of the d-axis, the rotor in the permanent magnet synchronous motor is converged by the high-frequency injection method, and then the current is input to the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction. The actual positive direction of the d-axis of the permanent magnet synchronous motor is determined according to the rotation direction of the rotor and the estimated positive direction of the d-axis. Since the estimated positive direction of the d-axis may coincide with the actual positive direction of the d-axis, or may be opposite to the actual positive direction of the d-axis, and after the high-frequency injection rotor converges and the current is input to the q-axis, the coincidence of the two estimated positive directions of the d-axis and the actual positive direction of the d-axis will correspond to different rotor rotation directions. Therefore, according to the rotor rotation direction, it is possible to quickly and accurately determine whether the current estimated positive direction of the d-axis is the actual positive direction of the d-axis.

[0102] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation described above is only illustrative, for example, the division of the modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0103] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0104] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0105] If the integrated units in the above other embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially 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, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), disk or optical disk and other media that can store program codes.

[0106] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining the positive direction of the d-axis of a permanent magnet synchronous motor, characterized in that: The method comprises: Construct an estimated dq coordinate system and determine the estimated positive direction of the d-axis; Inputting a high-frequency cosine voltage to the d-axis of the permanent magnet synchronous motor, and waiting for the rotor position in the permanent magnet synchronous motor to converge; After the rotor position in the permanent magnet synchronous motor converges, inputting current into the q-axis of the permanent magnet synchronous motor to obtain the rotor rotation direction; The d-axis positive direction is determined according to the rotor rotation direction and the estimated d-axis positive direction.

2. The method according to claim 1, characterized in that: Determining the positive direction of the d-axis according to the rotor rotation direction and the estimated positive direction of the d-axis comprises: In response to the rotor rotating in the forward direction, the estimated d-axis positive direction is determined as the d-axis positive direction. In response to the rotor rotating in the reverse direction, the estimated d-axis positive direction is determined as the d-axis negative direction.

3. The method according to claim 1, characterized in that Determining the positive direction of the d-axis according to the rotor rotation direction and the estimated positive direction of the d-axis comprises: Acquire the q-axis feedback current and the rotor feedback speed, wherein the rotor feedback speed is a positive speed, indicating that the rotor rotation direction is forward, and the rotor feedback speed is a negative speed, indicating that the rotor rotation direction is reverse; Multiplying the q-axis feedback current and the rotor feedback speed to obtain a judgment variable; In response to the judgment variable being greater than a preset positive threshold, the estimated d-axis positive direction is determined to be the d-axis positive direction; in response to the judgment variable being less than a preset negative threshold, the estimated d-axis positive direction is determined to be the d-axis negative direction.

4. The method according to claim 3, characterized in that The obtaining of the q-axis feedback current and the rotor feedback speed comprises: Acquire multiple sets of feedback information, each set of feedback information includes a q-axis feedback current and a rotor feedback speed, and the multiple sets of feedback information are obtained by correspondingly inputting multiple sets of currents with the same direction and different magnitudes to the q-axis; The step of multiplying the q-axis feedback current by the rotor feedback speed to obtain a judgment variable includes: Multiplying the q-axis feedback current and the rotor feedback speed in each group to obtain multiple groups of judgment variables; In response to the judgment variable being greater than a preset positive threshold, determining the estimated positive direction of the d-axis to be the positive direction of the d-axis, and in response to the judgment variable being less than a preset negative threshold, determining the estimated positive direction of the d-axis to be the negative direction of the d-axis, comprises: The multiple groups of judgment variables are judged, and in response to the judgment variable being greater than the preset positive threshold value for more than the preset number of times, the estimated positive direction of the d-axis is determined to be the positive direction of the d-axis; in response to the judgment variable being less than the preset negative threshold value for more than the preset number of times, the estimated positive direction of the d-axis is determined to be the negative direction of the d-axis.

5. The method according to claim 1, characterized in that The q-axis input current to the permanent magnet synchronous motor includes: A current that increases with time is input to a q-axis of the permanent magnet synchronous motor.

6. The method according to claim 5, characterized in that The rate at which the current value of the current input to the q-axis increases over time is a preset value.

7. The method according to claim 1, characterized in that The current input to the q-axis of the permanent magnet synchronous motor does not exceed a preset maximum current value of the frequency converter in the permanent magnet synchronous motor.

8. The method according to claim 1, characterized in that: When a high-frequency cosine voltage is input to the d-axis of the permanent magnet synchronous motor, the rotor speed of the permanent magnet synchronous motor is less than a preset speed.

9. An electronic device, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store program data, and the program data can be executed by the processor to implement the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: Program data is stored and can be executed by a processor to implement the method according to any one of claims 1 to 8.

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