Synchronous reluctance motor sensorless control inductance online identification method and system

Abstract

The invention provides a synchronous reluctance motor sensorless control inductance online identification method and system. The method comprises the following steps: obtaining a determined injected high-frequency square wave period according to a synchronous reluctance motor torque balance formula; the synchronous reluctance motor injects high-frequency voltage on a direct axis and a quadrature axis according to the determined injected high-frequency square wave period in the working process; 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 high-frequency voltage signal expressions injected in a direct axis and a quadrature axis, and substituting the high-frequency voltage signal expressions 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; on the basis of an inductance online identification expression, a difference value, an injected high-frequency square wave period and an injected high-frequency voltage amplitude are solved through the maximum value and the minimum value of dq shaft system current obtained through sampling in each half period, and direct-axis inductance and quadrature-axis inductance which are identified online are obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of identification in synchronous reluctance motor control, and in particular relates to a method and system for online identification of sensorless control inductance of a synchronous reluctance motor. Background Art

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

[0003] For the control of synchronous reluctance motors, the most widely used is the vector oriented control technology. The high performance control of synchronous reluctance motors requires precise rotor position, which is generally obtained by installing mechanical sensors. In large-scale production, the presence of sensors will increase the overall cost of the system. At the same time, due to the wear or aging of the sensors, regular inspection and maintenance are also required, which increases the maintenance cost and complexity.

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

[0005] Commonly used sensorless control methods can be divided into two categories, those suitable for zero and low speed and those suitable for medium and high speed. The zero and low speed methods include high-frequency square wave injection, high-frequency sine wave injection and high-frequency pulse signal injection.

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

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

[0008] The main online identification methods include the least square 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 and poor applicability. For example, CN117498744A_A low-speed sensorless control method of a synchronous reluctance motor based on high-frequency injection performs online identification of inductance parameters during the operation of the synchronous reluctance motor, and realizes simultaneous observation of angular position and inductance parameters. In addition, a four-vector high-frequency square wave voltage injection method is adopted to minimize the amount of calculation and reduce the impact 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 calculation load. Summary of the invention

[0009] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a method for online identification of sensorless control inductance of a synchronous reluctance motor, which can weaken the torque fluctuation injected by dual axes, identify the inductance of the AC and DC axes online, and has fast convergence speed and good dynamic responsiveness.

[0010] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

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

[0012] The injected high frequency square wave period is determined according to the torque balance formula of the synchronous reluctance motor;

[0013] During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and the quadrature axis according to the determined injected high-frequency square wave period;

[0014] A mathematical model of synchronous reluctance motor is established, and the high-frequency voltage equation of synchronous reluctance motor is obtained based on the model;

[0015] Obtain the high-frequency voltage signal expression injected into the direct axis and the quadrature axis, and substitute the high-frequency voltage signal expression into the high-frequency voltage equation to obtain the high-frequency current change expression;

[0016] The inductance online identification expression is obtained based on the high-frequency current variation expression;

[0017] Based on the online identification expression of inductance, the direct-axis and quadrature-axis inductances are obtained 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.

[0018] As a further technical solution, the torque balance formula of the synchronous reluctance motor makes the integral value of the base frequency torque and the integral value of the high frequency torque within one cycle equal.

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

[0020]

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

[0022] As a further technical solution, the synchronous reluctance motor includes:

[0023] The three-phase current of the synchronous reluctance motor is collected, the three-phase current is transformed to obtain the αβ axis current, and the current is discretized to obtain the fundamental frequency αβ axis current and the high frequency αβ axis current;

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

[0025] Inject high-frequency square waves into the dq axis system;

[0026] Convert the high-frequency square wave of the dq axis system to the αβ axis system, and obtain the high-frequency voltage expression of the αβ axis system;

[0027] The high-frequency voltage equation of the dq axis system is converted to the αβ axis system, and the high-frequency voltage expression of the αβ axis system is obtained;

[0028] Substituting the αβ axis high frequency voltage into the αβ axis high frequency voltage expression, we can get the relationship expression between the current change value and the rotor position.

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

[0030] 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.

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

[0032]

[0033] Among them, L d , L q is the direct-axis inductance and quadrature-axis inductance to be identified, I d-max ,I q-max It is the maximum value of the d-axis and q-axis sampling currents in the half cycle of the high-frequency square wave injection period, I d-min ,I q-min The minimum value of the d-axis and q-axis sampling currents within a half cycle.

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

[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 the synchronous reluctance motor torque balance formula;

[0037] During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and the quadrature axis according to the determined injected high-frequency square wave period;

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

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

[0041] The online identification module is configured as follows: based on the online identification expression of inductance, 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 are calculated to obtain the online identified direct-axis and quadrature-axis inductances.

[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 current sampled in each half cycle, and can identify the direct and quadrature axis inductances online based on the dq axis high-frequency current equation. 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 of injecting opposite high-frequency voltages into the dq axis system to realize online identification of the inductance of the synchronous reluctance motor in operation. At the same time, since the traditional method uses a single-axis injection of high-frequency square waves to realize sensorless control of the synchronous reluctance motor, the periodic integral of the single high-frequency square wave cannot be adjusted to zero, resulting in periodic torque fluctuations in the operation of the synchronous reluctance motor. The present invention adjusts the period of the dual-axis injection of high-frequency square waves so that the torque integral within one period is zero, thereby achieving the effect of weakening the torque, and realizing rapid online identification of inductance and torque fluctuation reduction.

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

[0046] The accompanying drawings in the specification, 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 It 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 2is a position estimation structure of the present invention;

[0049] Figure 3 It is a schematic diagram of the high frequency injection square wave and the change of dq axis current according to 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 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;

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

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

[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 300r / min, 2Nm; the design operating condition from 2 to 4 seconds is 500r / min, 2Nm. DETAILED DESCRIPTION

[0055] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those 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 specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0057] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0058] Embodiment 1

[0059] See attached Figure 1 As shown, this embodiment discloses a method for online identification of sensorless control inductance of a synchronous reluctance motor, comprising: Step 1: simultaneously injecting high-frequency square wave voltages of the same amplitude and opposite value into two axes of a rotating shaft system, and responding with high-frequency current.

[0060] The torque is calculated from the current, inductance and pole pair information. According to the torque balance formula, the integral value of the base frequency torque in one cycle is equal to the integral value of the high frequency torque. In theory, the torque change is 0 in one high frequency injected square wave cycle, even if the integral value of the base frequency torque in one cycle is subtracted from the integral value of the high frequency torque to be zero.

[0061] In this implementation example, the torque balance formula is:

[0062]

[0063] T i is the high frequency injected square wave period, T ef is the fundamental frequency torque, T eh High frequency torque.

[0064] The torque equation for a synchronous reluctance motor is:

[0065]

[0066] Where, T e is the output torque of the synchronous reluctance motor, n p is the number of motor pole pairs, i d 、i q is the dq axis current, L d , L q are the direct-axis and quadrature-axis inductances.

[0067] Substituting the fundamental frequency current and high frequency current into the torque balance formula, the torque balance formula within one cycle is as follows:

[0068]

[0069] In the formula, i df 、i qf is the fundamental frequency dq axis current; I dh (t), I qh (t) is the function of dq axis current including time; T i is the cycle time of the high frequency injection voltage.

[0070] The high frequency current expression in one cycle is:

[0071]

[0072] Where U in is the injected high frequency voltage amplitude.

[0073] Substituting the time-containing function of the dq axis current into the torque balance formula within one cycle, 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. d , L q is the direct-axis and quadrature-axis inductance, U in is the injected high frequency voltage amplitude, n p is the number of motor pole pairs.

[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] Among them, i df 、i qf is the fundamental frequency current of the dq axis system, L d , L q is the direct-axis and quadrature-axis inductance, U in The high-frequency injection square wave amplitude is set in this way to weaken the torque ripple.

[0079] Therefore, the period of the injected high-frequency square wave is determined according to the dq-axis current, dq-axis inductance and amplitude of the high-frequency injected square wave during steady-state operation, which can weaken the torque ripple.

[0080] Since the normally injected high-frequency square wave will have a problem of large torque fluctuation, which is expressed in the formula as not being 0 according to the torque balance formula, the sub-technical solution of this embodiment adopts dual-axis injection to control the torque integral of one injection cycle to be 0, thereby achieving the purpose of weakening the torque fluctuation. The simulation results also show that the above method is reasonable.

[0081] Step 2: Control operation of the synchronous reluctance motor after high frequency injection of square wave.

[0082] The three-phase current output by the synchronous reluctance motor is sampled to obtain the visible three-phase current i a 、i b 、i c According to the collected three-phase current, the αβ axis current i is obtained through CLARK transformation 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] The high-frequency dq axis voltage equation is converted to the αβ axis system to obtain the high-frequency current equation of the αβ axis system, which is used to construct a phase-locked loop:

[0085]

[0086] In the formula, i αh 、i βh is the αβ axis high frequency current, u αh 、u βh is the high frequency voltage of αβ axis, 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] In the formula, Δi αh , Δi βh is the difference in high-frequency current change on the αβ axis, and ΔT is the time difference corresponding to the current change.

[0090] Inject high frequency square wave into dq axis system:

[0091]

[0092] In the formula, 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 the dq axis system to the αβ axis system.

[0096]

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

[0098]

[0099] Substituting the αβ axis high frequency voltage into the αβ axis high frequency voltage expression, the relationship expression between the current change value and the rotor position can be obtained:

[0100]

[0101] By vector cross multiplication we get:

[0102]

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

[0104] Since the rotor position estimation error is a minimum value, we can get:

[0105] sinθ err ≈θ err

[0106] The rotor position error expression is:

[0107]

[0108] The rotor position error θ err Through PI regulation, the estimated speed is obtained Integrate the estimated speed to get the estimated rotor position That is, estimate the angle between the rotating coordinate system and the actual stationary coordinate system, and estimate the rotation speed and reference speed Make the difference and get the current reference torque through the speed loop PI Estimate the MTPA curve to distribute the current and obtain the reference dq axis current Current, make the difference between the reference dq axis current and the base frequency dq axis current, and adjust the difference through the current loop PI to obtain the reference dq axis voltage Reference dq axis voltage The high frequency voltage u set in step 1 dh 、u qhAdd and obtain 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 realize 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 current in each high-frequency injected square wave cycle, and obtain the quadrature axis and direct axis inductances according to 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 the half cycle of the high-frequency square wave injection period, I d-min ,I q-min The minimum value of the dq axis sampling current in a half cycle.

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

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

[0114]

[0115] In the formula, 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 axis and quadrature axis, 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] In the formula, u dh 、u qh is the dq axis high frequency voltage, i dh 、iqh is the dq axis high frequency current.

[0119] In order to perform sensorless control and obtain the rotor position and speed, the expression of the dq axis high-frequency voltage signal injected into the direct axis and quadrature axis is:

[0120]

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

[0122] Substituting the dq axis high frequency injection voltage into the dq axis high frequency voltage equation, the dq axis high frequency current change expression is obtained:

[0123]

[0124] In the formula, di / dt is approximately Δi / ΔT, Δi dh , Δi qh is the difference in current change between the d and q axes, and ΔT is the change time.

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

[0126] The high-frequency voltage of the dq axis system in the positive half cycle is:

[0127]

[0128] Therefore, in T i The expression of the current change at time / 2 relative to time 0 is:

[0129]

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

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

[0132]

[0133] Therefore, in T i Time relative to T i / 2 moment current change expression:

[0134]

[0135] In the formula, (T i / 2~T i ) indicates T i / 2 to T i Current change time.

[0136] In a half cycle of a high-frequency voltage square wave, the dq-axis high-frequency voltage is always a positive value or a negative value, and the dq-axis current can be approximated to rise or fall at a fixed slope. When the high-frequency square wave voltage changes sign after half a cycle, the dq-axis current reaches its maximum or minimum value. The αβ-axis current is converted into the dq axis through PARK, and the sampling result is calculated once every half cycle to find the maximum and minimum values ​​of the dq axis in each half cycle.

[0137] The current results of multiple sampling within a high-frequency square wave cycle are used to obtain the maximum current and minimum current of each half cycle of the sampled high-frequency injected square wave, and the inductor online identification expression can be obtained:

[0138]

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

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

[0141] In step 2, a high-frequency square wave with opposite amplitude is injected into the dq axis system, and the injection period of the high-frequency square wave is deduced from the torque balance equation to weaken the torque fluctuation; the sampled three-phase current is transformed by CLARK to obtain the αβ axis system current, and the average value is obtained by lagging the current value of half a period to obtain the αβ axis fundamental frequency current, and the difference average value is obtained to obtain the αβ axis high-frequency current; according to the high-frequency current of the αβ axis system, the rotor position error is determined by vector cross multiplication; according to the rotor position error, the estimated speed is determined by PI, and the estimated rotor position is determined by the integral of the estimated speed; the improved high-frequency square wave injection according to the present invention can reduce the torque fluctuation during sensorless control.

[0142] refer to Figure 5 Figure 6 Figure 7 , is an embodiment of the present invention, and provides a sensorless control inductance online identification method for a synchronous reluctance motor based on dual-axis high-frequency square wave injection. In order to further verify the beneficial effects of the present invention, a scientific demonstration is carried out through simulation experiments as follows:

[0143] like Figure 5 The figure shows the rotor position error Simulink simulation diagram of the sensorless control inductance online identification method of the synchronous reluctance motor based on dual-axis high-frequency square wave injection. 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 has no up and down fluctuation.

[0145] like Figure 7 and Figure 8 As shown in the figure, it is a Simulink simulation diagram of the direct-axis and quadrature-axis inductance identification of the synchronous reluctance motor sensorless control inductance online identification method 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] Embodiment 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] Embodiment 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 executes the steps of the above method when executed by a processor.

[0151] Embodiment 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 the 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 expression injected into the direct axis and the quadrature axis, and substitute the high-frequency voltage signal expression into the high-frequency voltage equation to obtain the high-frequency current change expression;

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

[0158] The online identification module is configured as follows: based on the online identification expression of inductance, 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 are calculated to obtain the online identified direct-axis and quadrature-axis inductances.

[0159] Embodiment 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 the method embodiment 1, and the specific implementation method can refer to the relevant description part of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

[0162] Those skilled in the art should understand that the modules or steps of the present invention described above can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made 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 implementation mode 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 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 in that: include: The injected high frequency square wave period is determined according to the torque balance formula of the synchronous reluctance motor; During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and the quadrature axis according to the determined injected high-frequency square wave period; A mathematical model of synchronous reluctance motor is established, and the high-frequency voltage equation of synchronous reluctance motor is obtained based on the model; Obtain the high-frequency voltage signal expression injected into the direct axis and the quadrature axis, and substitute the high-frequency voltage signal expression 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 variation expression; Based on the online identification expression of inductance, the direct-axis and quadrature-axis inductances are obtained 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.

2. A method for online identification of sensorless control inductance of a synchronous reluctance motor as claimed in claim 1, characterized in that: The torque balance formula of the synchronous reluctance motor makes the integral value of the base frequency torque equal to the integral value of the high frequency torque in one cycle.

3. A method for online identification of sensorless control inductance of a synchronous reluctance motor as claimed in claim 1, characterized in that: The expression for determining the injected high-frequency square wave period is: Among them, i df 、i qf is the fundamental frequency dq axis current, T i is the period of the injected high-frequency square wave, L d , L q are the direct-axis inductance and the quadrature-axis inductance.

4. A method for online identification of sensorless control inductance of a synchronous reluctance motor as claimed in claim 1, characterized in that: The synchronous reluctance motor is working in the following process: The three-phase current of the synchronous reluctance motor is collected, the three-phase current is transformed to obtain the αβ axis current, and the current is discretized to obtain the fundamental frequency αβ axis current and the high frequency αβ axis current; The high-frequency dq axis voltage equation is converted to the αβ axis system to obtain the high-frequency current equation; Inject high-frequency square waves into the dq axis system; Convert the high-frequency square wave of the dq axis system to the αβ axis system, and obtain the high-frequency voltage expression of the αβ axis system; The high-frequency voltage equation of the dq axis system is converted to the αβ axis system, and the high-frequency voltage expression of the αβ axis system is obtained; Substituting the αβ axis high frequency voltage into the αβ axis high frequency voltage expression, we can get the relationship expression between the current change value and the rotor position. Based on the current change value and the rotor position relationship expression, the rotor position error expression is obtained; 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.

5. The method for online identification of sensorless control inductance of a synchronous reluctance motor as claimed in claim 1, characterized in that: The inductance online identification expression is specifically: Among them, L d , L q is the direct-axis inductance and quadrature-axis inductance to be identified, I d-max ,I q-max It is the maximum value of the d-axis and q-axis sampling currents in the half cycle of the high-frequency square wave injection period, I d-min ,I q-min The minimum value of the d-axis and q-axis sampling currents within a half cycle.

6. A method for online identification of sensorless control inductance of a synchronous reluctance motor as claimed in claim 1, characterized in that: The injected high frequency square wave is a high frequency square wave with opposite amplitude.

7. A synchronous reluctance motor sensorless control inductance online identification system, characterized in that: 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; During operation, the synchronous reluctance motor injects high-frequency voltage into the direct axis and the 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 expression injected into the direct axis and the quadrature axis, and substitute the high-frequency voltage signal expression 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 variation expression; The online identification module is configured as follows: based on the online identification expression of inductance, 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 are calculated to obtain the online identified direct-axis and quadrature-axis inductances.

8. 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 6 is implemented.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method described in any one of claims 1 to 6 are implemented.

10. 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 described in any one of claims 1 to 6 are performed.

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