Sensorless control inductance online identification method and system for synchronous reluctance motor

Abstract

The application provides a sensorless control inductance online identification method and system for a synchronous reluctance motor, and comprises the following steps: obtaining a determined high-frequency square wave period injected according to a torque balance formula of the synchronous reluctance motor; injecting high-frequency voltages in the direct axis and the quadrature axis of the synchronous reluctance motor according to the determined high-frequency square wave period during operation of the synchronous reluctance motor; establishing a mathematical model of the synchronous reluctance motor, and obtaining a high-frequency voltage equation of the synchronous reluctance motor based on the model; obtaining a high-frequency voltage signal expression injected in the direct axis and the quadrature axis, and bringing the high-frequency voltage signal expression into the high-frequency voltage equation to obtain a high-frequency current change expression; obtaining an inductance online identification expression based on the high-frequency current change expression; and obtaining online identified direct-axis and quadrature-axis inductances based on the inductance online identification expression, the difference between maximum and minimum values of dq axis system currents obtained by sampling every half cycle, the injected high-frequency square wave period and the injected high-frequency voltage amplitude.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of identification technology in synchronous reluctance motor control, and particularly relates to a synchronous reluctance motor sensorless control inductance online identification method and system. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] For the control of synchronous reluctance motors, the most widely used is to adopt vector-oriented control technology. High-performance control of synchronous reluctance motors requires accurate rotor position, which is generally obtained by installing mechanical sensors. In mass production, the presence of sensors increases the overall cost of the system. At the same time, due to wear or aging of the sensors, regular inspection and maintenance are required, increasing maintenance costs and complexity.

[0004] In addition, there is also a sensorless control technology for motors in the prior art by detecting motor output current signals and voltage signals, and sensorless control technology for synchronous reluctance motors has gradually become one of the research hotspots in the field of motor control.

[0005] Common sensorless control methods can be divided into two categories: methods suitable for zero or low speed and methods suitable for medium or high speed. Among them, the methods suitable for zero or low speed are high-frequency square wave injection, high-frequency sinusoidal wave injection and high-frequency pulse signal injection.

[0006] When high-frequency signal injection is used, additional torque fluctuations and noise are introduced. At the same time, the estimation error of the rotor position is affected by the inductance, and existing inductance identification methods can be divided into offline identification and online identification methods.

[0007] Although offline identification parameters can obtain accurate identification results, they cannot accurately reflect the parameter situation under various different working conditions, and at the same time, with the wear and aging of the motor, the offline identification result error will increase.

[0008] Online identification methods mainly include least squares method, model reference adaptive method, extended Kalman filter method and artificial intelligence algorithm, but there are problems such as high computational complexity, slow convergence speed, poor applicability, etc. For example, CN117498744A A synchronous reluctance motor low-speed sensorless control method based on high-frequency injection, inductance parameter online identification is performed during the operation of the synchronous reluctance motor, and simultaneous observation of the angle position and inductance parameter is realized. In addition, a four-vector high-frequency square wave voltage injection method is adopted, which maximally reduces the computational load and reduces the influence of the injected voltage pulse on the sensorless control system. The existing synchronous reluctance motor parameter identification method has the problems of slow response speed, long convergence time and high computational load. SUMMARY

[0009] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a sensorless control inductance online identification method for a synchronous reluctance motor, which can weaken the torque fluctuation of double-axis injection, online identify direct-axis and quadrature-axis inductance, and has fast convergence speed and good dynamic response.

[0010] In order to achieve the above-mentioned purpose, one or more embodiments of the present application provide the following technical solutions:

[0011] In the first aspect, a sensorless control inductance online identification method for a synchronous reluctance motor is disclosed, comprising:

[0012] determining an injected high-frequency square wave period according to a torque balance formula of the synchronous reluctance motor;

[0013] injecting high-frequency voltages in the direct-axis and the quadrature-axis according to the determined high-frequency square wave period during the operation of the synchronous reluctance motor;

[0014] establishing a mathematical model of the synchronous reluctance motor, and obtaining a high-frequency voltage equation of the synchronous reluctance motor based on the model;

[0015] obtaining high-frequency voltage signal expressions injected in the direct-axis and the quadrature-axis, and bringing the high-frequency voltage signal expressions into the high-frequency voltage equation to obtain a high-frequency current change expression;

[0016] obtaining an inductance online identification expression based on the high-frequency current change expression;

[0017] obtaining online identified direct-axis and quadrature-axis inductances based on the inductance online identification expression, the difference between the maximum and minimum values of the dq-axis system currents obtained by sampling every half cycle, the injected high-frequency square wave period, and the injected high-frequency voltage amplitude.

[0018] As a further technical solution, the torque balance formula of the synchronous reluctance motor is that the integral values of the fundamental frequency torque and the high-frequency torque in one period are equal.

[0019] As a further technical solution, the expression for determining the injected high-frequency square wave period is:

[0020]

[0021] wherein, i df , i qf is the fundamental frequency dq-axis current, T i is the injected high-frequency square wave period, L d , L q is the direct-axis inductance and the quadrature-axis inductance.

[0022] As a further technical solution, during the operation of the synchronous reluctance motor, the method comprises:

[0023] Three-phase currents of the synchronous reluctance motor are collected, and αβ-axis currents are obtained by transforming the three-phase currents, and the αβ-axis currents are discretized to obtain base frequency αβ-axis currents and high frequency αβ-axis currents;

[0024] The high frequency dq-axis voltage equation is converted to the αβ-axis system to obtain a high frequency current equation;

[0025] A high frequency square wave is injected in the dq-axis system;

[0026] The high frequency square wave in the dq-axis system is converted to the αβ-axis system to obtain an αβ-axis high frequency voltage expression;

[0027] The high frequency voltage equation in the dq-axis system is converted to the αβ-axis system to obtain an αβ-axis high frequency voltage expression;

[0028] The αβ-axis high frequency voltage is brought into the αβ-axis high frequency voltage expression to obtain a current change value and rotor position relationship expression;

[0029] A rotor position error expression is obtained based on the current change value and rotor position relationship expression;

[0030] The rotor position error is adjusted to obtain an estimated speed, and the estimated speed is integrated to obtain an estimated rotor position, i.e., an angle between an estimated rotating coordinate system and an actual stationary coordinate system.

[0031] As a further technical solution, the inductance online identification expression is specific to:

[0032]

[0033] wherein, L d , L q are the direct-axis inductance and quadrature-axis inductance to be identified, I d-max , I q-max are the maximum values of the d-axis and q-axis sampling currents in a half cycle of the high frequency square wave injection period, I d-min , I q-min are the minimum values of the d-axis and q-axis sampling currents in the half cycle.

[0034] As a further technical solution, the injected high frequency square wave is a high frequency square wave with opposite amplitudes.

[0035] In a second aspect, a synchronous reluctance motor sensorless control inductance online identification system is disclosed, comprising:

[0036] The injected high frequency square wave determination module is configured to: determine the injected high frequency square wave period according to a synchronous reluctance motor torque balance formula;

[0037] The synchronous reluctance motor injects a high frequency voltage in the direct axis and the quadrature axis according to the determined high frequency square wave period during operation;

[0038] The inductance online identification expression establishment module is configured to: establish a mathematical model of the synchronous reluctance motor and obtain a high-frequency voltage equation of the synchronous reluctance motor based on the model;

[0039] Obtain the high-frequency voltage signal expressions injected into the direct axis and quadrature axis, and substitute the high-frequency voltage signal expressions into the high-frequency voltage equation to obtain the high-frequency current change expression;

[0040] The online identification expression of inductance is obtained based on the high-frequency current variation expression;

[0041] The online identification module is configured to obtain the online identified direct-axis and quadrature-axis inductances based on the online inductance identification expression by calculating the difference between the maximum and minimum values ​​of the dq axis current sampled in each half cycle, the injected high-frequency square wave period, and the injected high-frequency voltage amplitude.

[0042] One or more of the above technical solutions have the following beneficial effects:

[0043] The technical solution of the present invention, in the case of sensorless control, obtains the difference between the maximum and minimum values ​​of the dq axis system current sampled in each half cycle. According to the dq axis high-frequency current equation, the direct-axis and quadrature-axis inductances can be identified online. The identification speed is fast, the dynamic responsiveness is good, and the torque fluctuation injected by the dual axes can be weakened.

[0044] The technical solution of the present invention proposes a method for online identification of the inductance of a synchronous reluctance motor in operation by injecting opposite high-frequency voltages into the dq axis system. Furthermore, because the conventional method uses a single axis to inject a high-frequency square wave to achieve sensorless control of a synchronous reluctance motor, the periodic integral of the single high-frequency square wave cannot be adjusted to zero, resulting in periodic torque fluctuations during operation of the synchronous reluctance motor. The present invention adjusts the period of the dual-axis injected high-frequency square wave to zero the torque integral within one period, thereby achieving the effect of reducing torque, enabling rapid online identification of inductance and reduction of torque fluctuations.

[0045] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0047] Figure 1 This is a flow chart of the sensorless control and online inductance identification of the synchronous reluctance motor with dual-axis high-frequency square wave injection according to the present invention;

[0048] Figure 2It is a position estimation structure of the present invention;

[0049] Figure 3 This is a schematic diagram of the high-frequency square wave injection and the dq axis current changes of the present invention;

[0050] Figure 4 It is the relationship diagram of each coordinate system, the dq axis system is the actual rotating coordinate system, The axis system is the estimated rotating coordinate system, the αβ axis system is the actual stationary coordinate system, and the θ e is the angle between the actual rotating coordinate system and the actual stationary coordinate system, To estimate the angle between the rotating coordinate system and the actual stationary coordinate system, θ err is the difference between the estimated rotor position and the actual rotor position;

[0051] Figure 5 The difference between the actual rotor position and the estimated rotor position is identified for rotor position identification;

[0052] Figure 6 This is the result of torque fluctuation reduction. The solid line curve is the high-frequency square wave injected into the dq shaft system, and the dashed line curve is the torque fluctuation curve injected into the dq shaft system with the same high-frequency square wave. The design operating condition from 0 to 2 seconds is 300 r / min, 2 Nm; the design operating condition from 2 to 4 seconds is 500 r / min, 2 Nm.

[0053] Figure 7 The solid line curve is the direct-axis inductance identification result of the present invention. The solid line curve is the direct-axis inductance estimated by online identification of the synchronous reluctance motor, and the dashed line curve is the actual quadrature-axis inductance of the motor. The design operating condition from 0 to 2 seconds is 300 r / min, 2 Nm; the design operating condition from 2 to 4 seconds is 500 r / min, 2 Nm.

[0054] Figure 8 It is the quadrature-axis inductance identification result of the present invention. The solid-line marked curve is the quadrature-axis inductance estimated by online identification of the synchronous reluctance motor, and the dotted-line marked curve is the actual quadrature-axis inductance of the motor. The design operating condition from 0 to 2 seconds is 300 r / min, 2 Nm; the design operating condition from 2 to 4 seconds is 500 r / min, 2 Nm. DETAILED DESCRIPTION

[0055] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0056] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0057] In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0058] Embodiment one

[0059] Referring to the accompanying Figure 1 The embodiment discloses a sensorless control inductance online identification method for a synchronous reluctance motor, comprising the following steps: step one: injecting high-frequency square wave voltages with the same amplitude and opposite directions into a rotating shaft system double shaft, and responding to high-frequency currents.

[0060] Torque is obtained by current, inductance and pole pair number information, according to the torque balance formula, the integral value of the base frequency torque in a period is equal to the integral value of the high-frequency torque, and theoretically, the change of the torque in a high-frequency injection square wave period is 0, that is, the integral of the base frequency torque in a period is subtracted from the integral of the high-frequency torque to be zero.

[0061] In the embodiment, the torque balance formula is as follows:

[0062]

[0063] T i is a high-frequency injection square wave period, T ef is a base frequency torque, T eh is a high-frequency torque.

[0064] Torque equation of the synchronous reluctance motor:

[0065]

[0066] In the formula, T e is an output torque of the synchronous reluctance motor, n p is a pole pair number of the motor, i d , i q are dq-axis currents, L d , L q are direct-axis and quadrature-axis inductances.

[0067] The base frequency current and the high-frequency current are brought into the torque balance formula, and the torque balance formula in a period is as follows:

[0068]

[0069] In the formula, i df , i qf are base frequency dq-axis currents; I dh (t), I qh (t) are time-dependent functions of the dq-axis currents; T i is a period time of the high-frequency injection voltage.

[0070] The high-frequency current expression in a period is as follows:

[0071]

[0072] In the formula, U in is the amplitude of the injected high-frequency voltage.

[0073] The torque balance formula is obtained by bringing the time function of the dq-axis current into the torque balance formula within a period, and the specific expression of the torque balance formula is as follows:

[0074]

[0075] In the formula, i df , i qf is the fundamental frequency dq-axis current, T i is the high-frequency square wave injection period. L d , L q is the direct-axis and quadrature-axis inductance, U in is the amplitude of the injected high-frequency voltage, n p is the pole pair number of the motor.

[0076] Based on the above formula, the relationship between the high-frequency injected square wave voltage amplitude and the high-frequency injected square wave period is obtained:

[0077]

[0078] In the formula, i df , i qf is the dq-axis system fundamental frequency current, L d , L q is the direct-axis and quadrature-axis inductance, U in is the amplitude of the injected high-frequency square wave, and the high-frequency injected square wave thus set can weaken the torque fluctuation.

[0079] Therefore, according to the dq-axis current, the dq-axis inductance and the high-frequency injected square wave amplitude in the steady-state operation, the injected high-frequency square wave period is determined, and the torque fluctuation can be weakened.

[0080] Since the normally injected high-frequency square wave has the problem of large torque fluctuation, the expression on the formula is that the torque balance formula is not 0, so the dual-axis injection is adopted in the technical solution of the embodiment, the torque integral of one period of the injection is controlled to be 0, the purpose of weakening the torque fluctuation is achieved, and the simulation results also show that the above method is reasonable.

[0081] Step two: control operation of the synchronous reluctance motor after high-frequency injection of square waves.

[0082] The three-phase current i a , i b , i c output by the synchronous reluctance motor is obtained through sampling to obtain the visible three-phase current i α、i β , discretize it and separate the fundamental frequency αβ axis current i αf 、i βf and high-frequency αβ-axis current i αh 、i βh .

[0083] A phase-locked loop is constructed through high-frequency current expression to achieve sensorless control. The following is the detailed process.

[0084] Convert the high-frequency dq-axis voltage equation to the αβ-axis system to obtain the high-frequency current equation of the αβ-axis system, which is used to construct the phase-locked loop:

[0085]

[0086] Where i αh 、i βh is the αβ axis high frequency current, u αh 、u βh is the αβ axis high frequency voltage, L avg =(L d +L q ) / 2 is the average inductance, L dif =(L d -L q ) / 2 is the differential inductance, θ e is the angle between the rotating axis and the stationary axis.

[0087] See attached Figure 3 As shown in the figure, due to the high frequency of high-frequency voltage injection, di / dt can be approximated as Δi / ΔT, and the relationship between the high-frequency current change value and the rotor position can be obtained:

[0088]

[0089] Where Δi αh , Δi βh is the difference in high-frequency current change between the α and β axes, and ΔT is the time difference corresponding to the current change.

[0090] Inject high-frequency square waves into the dq axis system:

[0091]

[0092] Where u dh 、u qh is the high-frequency square wave voltage injected into the dq axis, and k is the number of half cycles of the high-frequency square wave injection period.

[0093] Convert the high-frequency square wave of the dq axis system to the αβ axis system:

[0094]

[0095] Where R(θe ) is the transformation matrix from dq-axis to αβ-axis.

[0096]

[0097] The expression of high-frequency voltage in αβ-axis is obtained:

[0098]

[0099] The expression of current variation and rotor position is obtained by bringing the high-frequency voltage in αβ-axis into the expression of high-frequency voltage in αβ-axis:

[0100]

[0101] The expression is obtained by vector cross multiplication:

[0102]

[0103] In the expression, θ err is the rotor position error, is the angle between the estimated rotating coordinate system and the actual stationary coordinate system, and Sign(U dh ) is the sign function of the d-axis high-frequency square wave injected into the dq-axis, as shown in FIG. 2. Figure 2

[0104] Since the rotor position estimation error is a minimum value, the following expression is obtained:

[0105] sinθ err ≈θ err

[0106] The expression of rotor position error is:

[0107]

[0108] The rotor position error θ err is regulated by PI to obtain the estimated speed The estimated speed is integrated to obtain the estimated rotor position The angle between the estimated rotating coordinate system and the actual stationary coordinate system is obtained, and the estimated speed is subtracted from the reference speed to obtain the current reference torque through the speed loop PI. The MTPA curve is estimated to distribute the current to obtain the reference dq-axis current The reference dq-axis current is subtracted from the fundamental frequency dq-axis current to obtain the reference dq-axis voltage through the current loop PI. The reference dq-axis voltage is subtracted from the high-frequency voltage u dh , u qh ​Add together and get the reference αβ axis voltage through inverse PARK transformation The voltage is used to control the duty cycle of the switch tube through SVPWM to control the synchronous reluctance motor and achieve sensorless control.

[0109] Step 3: See attached Figure 4 As shown, the αβ axis current i is obtained by Clark transformation based on the collected three-phase current α 、i β , the αβ axis current is transformed by PARK to obtain the dq axis current i d 、i q , compare the maximum and minimum values ​​of the dq axis currents in each high-frequency injection square wave cycle, and calculate the quadrature axis and direct axis inductances based on the high-frequency voltage equation. The inductance online identification expression is as follows:

[0110]

[0111] Among them, L d , L q To identify the direct-axis and quadrature-axis inductance, I d-max , I q-max It is the maximum value of the dq axis sampling current in half a period of the high-frequency square wave injection cycle, I d-min , I q-min The minimum value of the dq-axis sampling current within a half cycle.

[0112] The specific process of obtaining the inductance online identification expression in step 3 above is as follows:

[0113] Establish the mathematical model of dq-axis synchronous reluctance motor.

[0114]

[0115] Where u d 、u q is the dq axis voltage, i d 、i q is the dq axis current, L d , L q is the direct-axis and quadrature-axis inductance, R is the resistance, ω e is the electrical angular velocity.

[0116] When high-frequency voltage is injected into the direct and quadrature axes, the coupling part and the resistance voltage drop part are small, and the high-frequency dq axis voltage equation of the synchronous reluctance motor can be simplified to:

[0117]

[0118] Where u dh 、u qh is the dq axis high frequency voltage, i dh 、iqh is the high frequency current for dq axis.

[0119] To carry out sensorless control, the rotor position and speed are obtained, and the high frequency voltage signal expressions injected in the direct and quadrature axes are:

[0120]

[0121] U in is the amplitude of the injected high frequency voltage, and k is the number of half cycles of the injected high frequency square wave.

[0122] The high frequency injected voltage in the dq axis system is brought into the high frequency voltage equation in the dq axis system to obtain the high frequency current change expression in the dq axis system:

[0123]

[0124] In the formula, di / dt is approximately Δi / ΔT, Δi dh , Δi qh is the high frequency current change difference, and ΔT is the change time.

[0125] It can be seen that the current change value is proportional to the time change value.

[0126] In the positive half cycle, the high frequency voltage in the dq axis system is:

[0127]

[0128] Therefore, at the moment T i / 2, the current change value relative to the moment 0 is:

[0129]

[0130] In the formula, (0~T i / 2) represents the current change time from the moment 0 to the moment T i / 2.

[0131] Then, in the negative half cycle, the high frequency voltage in the dq axis system is:

[0132]

[0133] Therefore, at the moment T i , the current change value relative to the moment T i / 2 is:

[0134]

[0135] In the formula, (T i / 2~T i ) represents the current change time from the moment T i / 2 to the moment T i .

[0136] In one high-frequency voltage square wave half cycle, the dq-axis high-frequency voltage is always positive or always negative, and the dq-axis current can be approximately fixed slope rising or falling, when the high-frequency square wave voltage changes sign in a half cycle, the dq-axis current reaches the maximum or minimum value, the alpha-beta axis current is converted to dq-axis by PARK conversion, and the sampling result is calculated every half cycle to obtain the maximum and minimum values of the dq-axis every half cycle.

[0137] The current result of multiple sampling in one high-frequency square wave cycle is obtained, the maximum current and the minimum current of each sampling high-frequency injection square wave half cycle are obtained, and the inductance online identification expression is obtained:

[0138]

[0139] In the formula, I d-max , I q-max is the maximum value of the dq-axis current, I d-min , I q-min is the maximum value of the dq-axis current.

[0140] Therefore, the maximum and minimum values of the dq-axis current every cycle are subtracted, the reciprocal is obtained, and then multiplied by the high-frequency voltage amplitude and the half cycle time to identify the direct-axis and quadrature-axis inductances, as shown in the above expression.

[0141] In step two, high-frequency square waves with opposite amplitudes are injected in the dq-axis system, the injection period of the high-frequency square wave is obtained by torque balance equation, and the torque fluctuation is weakened; the sampled three-phase current is converted to the alpha-beta axis system current through CLARK conversion, the average value of the current value lagging by half a cycle is obtained to obtain the alpha-beta axis fundamental current, and the difference average value is obtained to obtain the alpha-beta axis high-frequency current; the rotor position error is determined by vector cross multiplication according to the alpha-beta axis high-frequency current; the estimated rotor position is determined by integrating the estimated speed determined by the PI according to the rotor position error; the improved high-frequency square wave injection of the application can reduce the torque fluctuation in sensorless control.

[0142] Reference Figure 5 Figure 6 Figure 7 It is an embodiment of the application to provide a sensorless control inductance online identification method for synchronous reluctance motors based on dual-axis high-frequency square wave injection, in order to further verify the beneficial effects of the application, the following scientific demonstration is carried out through simulation experiment:

[0143] As Figure 5 shown, it is a rotor position error Simulink simulation diagram in sensorless control inductance online identification method for synchronous reluctance motors based on dual-axis high-frequency square wave injection. From Figure 5It can be seen that in the steady-state operation stage, the estimated position is basically consistent with the true position, and the estimation error is small, which shows that this method can accurately obtain the rotor position in the steady state.

[0144] like Figure 6 The figure shows the rotor speed Simulink simulation diagram of the synchronous reluctance motor sensorless control inductance online identification method based on dual-axis high-frequency square wave injection. Figure 6 It can be seen from the figure that in steady state, when the same high-frequency square wave voltage is injected into the dq axis, the speed will fluctuate up and down, while when the designed high-frequency square wave voltage is injected into the dq axis, the speed fluctuation obviously does not fluctuate up and down.

[0145] like Figure 7 and Figure 8 The figure shows the direct-axis and quadrature-axis inductance identification Simulink simulation diagram of the online identification method of the sensorless control inductance of the synchronous reluctance motor based on dual-axis high-frequency square wave injection. Figure 7 and Figure 8 It can be seen that when the synchronous reluctance motor reaches a steady state, the inductance identification result also quickly reaches stability, and the inductance identification result is basically consistent with the actual inductance. The inductance identification speed is fast and the accuracy is high.

[0146] Example 2

[0147] The purpose of this embodiment is to provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

[0148] Example 3

[0149] The purpose of this embodiment is to provide a computer-readable storage medium.

[0150] A computer-readable storage medium stores a computer program, which, when executed by a processor, performs the steps of the above method.

[0151] Example 4

[0152] The purpose of this embodiment is to provide a synchronous reluctance motor sensorless control inductance online identification system, including:

[0153] The injected high-frequency square wave determination module is configured to: determine the injected high-frequency square wave period according to the synchronous reluctance motor torque balance formula;

[0154] During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and quadrature axis according to the determined injected high-frequency square wave period;

[0155] The inductance online identification expression establishment module is configured to: establish a mathematical model of the synchronous reluctance motor and obtain a high-frequency voltage equation of the synchronous reluctance motor based on the model;

[0156] Obtain the high-frequency voltage signal expressions injected into the direct axis and quadrature axis, and substitute the high-frequency voltage signal expressions into the high-frequency voltage equation to obtain the high-frequency current change expression;

[0157] The online identification expression of inductance is obtained based on the high-frequency current variation expression;

[0158] The online identification module is configured to obtain the online identified direct-axis and quadrature-axis inductances based on the online inductance identification expression by calculating the difference between the maximum and minimum values ​​of the dq axis current sampled in each half cycle, the injected high-frequency square wave period, and the injected high-frequency voltage amplitude.

[0159] Example 5

[0160] The purpose of this embodiment is to provide a computer program product containing instructions, which, when running on a computer, enables the computer to execute the methods and functions involved in any of the above embodiments.

[0161] The steps involved in the apparatus of the above embodiment correspond to those of the method embodiment 1. For detailed implementation, please refer to the relevant description of embodiment 1. The term "computer-readable storage medium" should be understood to mean a single medium or multiple media containing one or more instruction sets; it should also be understood to include any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and causing the processor to perform any method of the present invention.

[0162] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0163] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A method for online identification of sensorless control inductance of a synchronous reluctance motor, characterized by: include: The injected high-frequency square wave period is determined according to the torque balance formula of the synchronous reluctance motor; the expression for determining the injected high-frequency square wave period is specifically: in, i df 、 i qf Base frequency dq Shaft current, T i is the period of the injected high-frequency square wave, L d 、 L q are the direct-axis inductance and quadrature-axis inductance, U in is the injected high-frequency voltage amplitude; During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and quadrature axis according to the determined injected high-frequency square wave period; Establish a mathematical model of the synchronous reluctance motor and obtain the high-frequency voltage equation of the synchronous reluctance motor based on the model; Obtain the high-frequency voltage signal expressions injected into the direct axis and quadrature axis, and substitute the high-frequency voltage signal expressions into the high-frequency voltage equation to obtain the high-frequency current change expression; The inductance online identification expression is obtained based on the high-frequency current change expression; the inductance online identification expression is specifically: in, L d 、 L q are the direct-axis inductance and quadrature-axis inductance to be identified, I d-max 、 I q-max Inject high-frequency square waves into half the cycle d axis 、q The maximum value of the axis sampling current, I d-min 、 I q-min Within half cycle d axis 、q The minimum value of the axis sampling current; Based on the inductance online identification expression, the inductance is obtained by sampling every half cycle. dq The direct-axis and quadrature-axis inductances are identified online by taking the difference between the maximum and minimum values ​​of the shaft current, the period of the injected high-frequency square wave, and the amplitude of the injected high-frequency voltage.

2. The method for online identification of sensorless control inductance of a synchronous reluctance motor according to claim 1, wherein: In the torque balance formula of the synchronous reluctance motor, the integral value of the fundamental frequency torque and the integral value of the high frequency torque within one cycle are made equal.

3. The method for online identification of sensorless control inductance of a synchronous reluctance motor according to claim 1, wherein: The synchronous reluctance motor operates in the following ways: Collect the three-phase current of the synchronous reluctance motor and transform the three-phase current to obtain αβ The shaft current is discretized to obtain the fundamental frequency αβ Shaft current and high frequency αβ Shaft current; The high frequency dq The shaft voltage equation is converted to αβ Shaft system, obtain the high-frequency current equation; exist dq The shaft system injects high-frequency square waves; Will dq The high frequency square wave of the shaft system is converted to αβ Axis, get αβ The expression of high frequency voltage of shaft system; Will dq The high-frequency voltage equation of the shaft system is converted to αβ Axis, get αβ The expression of high frequency voltage of shaft system; Will αβ High frequency voltage brought into the shaft αβ The high-frequency voltage expression of the shaft system is used to obtain the relationship expression between the current change value and the rotor position; The rotor position error expression is obtained based on the current change value and the rotor position relationship expression; The rotor position error is adjusted to obtain the estimated speed, and the estimated speed is integrated to obtain the estimated rotor position, that is, the angle between the estimated rotating coordinate system and the actual stationary coordinate system.

4. The method for online identification of sensorless control inductance of a synchronous reluctance motor according to claim 1, wherein: The injected high-frequency square wave is a high-frequency square wave with opposite amplitude.

5. A synchronous reluctance motor sensorless control inductance online identification system, characterized by: include: The injected high-frequency square wave determination module is configured to: determine the injected high-frequency square wave period according to the synchronous reluctance motor torque balance formula; the expression for determining the injected high-frequency square wave period is specifically: in, i df 、 i qf Base frequency dq Shaft current, T i is the period of the injected high-frequency square wave, L d 、 L q are the direct-axis inductance and quadrature-axis inductance, U in is the injected high-frequency voltage amplitude; During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and quadrature axis according to the determined injected high-frequency square wave period; The inductance online identification expression establishment module is configured to: establish a mathematical model of the synchronous reluctance motor and obtain a high-frequency voltage equation of the synchronous reluctance motor based on the model; Obtain the high-frequency voltage signal expressions injected into the direct axis and quadrature axis, and substitute the high-frequency voltage signal expressions into the high-frequency voltage equation to obtain the high-frequency current change expression; The inductance online identification expression is obtained based on the high-frequency current change expression; the inductance online identification expression is specifically: in, L d 、 L q are the direct-axis inductance and quadrature-axis inductance to be identified, I d-max 、 I q-max Inject high-frequency square waves into half the cycle d axis 、q The maximum value of the axis sampling current, I d-min 、 I q-min Within half cycle d axis 、q The minimum value of the axis sampling current; The online identification module is configured as follows: Based on the inductance online identification expression, the inductance is obtained by sampling every half cycle. dq The direct-axis and quadrature-axis inductances are identified online by taking the difference between the maximum and minimum values ​​of the shaft current, the period of the injected high-frequency square wave, and the amplitude of the injected high-frequency voltage.

6. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method according to any one of claims 1 to 4 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are performed.

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