Inverter nonlinear compensation method, device, electronic equipment and medium

Abstract

The present invention provides an inverter nonlinear compensation method, device, electronic device and medium. The inverter nonlinear compensation method includes: collecting error voltage and inverter load current; obtaining saturated error voltage value and error voltage nonlinear function according to the error voltage and inverter load current; determining the first compensation voltage signal of the inverter according to the error voltage nonlinear function and motor phase current; performing coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal; realizing closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator; wherein the error voltage is the difference between the actual output voltage of the inverter and the expected output voltage. The present invention solves the technical problem that the steady-state and dynamic performance of the system are affected by the deviation voltage between the input and output voltages of the inverter.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to an inverter nonlinear compensation method, an inverter nonlinear compensation device, an electronic device and a readable storage medium. Background Art

[0002] With the increase of the switching frequency of power switch tube devices, the PWM control successfully applied in the inverter has promoted the development of motor drive control technology. The PWM inverter has the technical advantages of good output waveform and the ability to suppress or eliminate certain specific harmonics, and is widely used in the medium and low frequency fields. However, the actual output voltage and current waveforms of the inverter are easily affected by the nonlinear characteristics of the inverter and distorted. The nonlinear characteristics of the inverter mainly come from the dead time set by the power switch device, the non-ideal switching characteristics and the parasitic capacitance of the actual switch device. The dead time is to ensure the safe operation of the inverter and avoid the upper and lower power switch devices of the same bridge arm of the inverter from being turned on at the same time. Usually, a drive delay is added to the drive signal; the non-ideal switching characteristics mainly refer to the conduction voltage drop, turn-on delay and turn-off delay of the power switch device. In addition, the rise and fall speed of the inverter output voltage is greatly affected by the parasitic capacitance of the switch device, making the inverter output voltage present a trapezoidal wave. Moreover, at a very high switching frequency or a low output voltage, a very small dead time will greatly increase the harmonic content of the inverter output voltage, causing the motor to generate torque pulsation.

[0003] For sensorless AC motor vector control systems or direct torque control systems, it is necessary to accurately obtain the inverter output voltage. In order to simplify the system hardware and software design and implementation, the inverter input voltage is often used instead of the inverter output voltage. However, due to the existence of inverter nonlinearity, there is a deviation between the inverter input and output voltages. The existence of deviation voltage will directly affect the steady-state and dynamic performance of the system. Summary of the invention

[0004] The invention solves the technical problem that the steady state and dynamic performance of the system are affected by the deviation voltage between the input and output voltages of the inverter.

[0005] To solve the above problems, the present invention provides an inverter nonlinear compensation method, which includes: collecting error voltage and inverter load current; obtaining a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current; determining a first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current; performing coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal; and realizing closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of a current loop PI regulator; wherein the error voltage is the difference between the actual output voltage and the expected output voltage of the inverter.

[0006] In one example of the present invention, a saturated error voltage value and an error voltage nonlinear function are obtained based on the error voltage and the inverter load current, including: obtaining multiple data groups by applying different voltage excitations, wherein the data groups include the error voltage and the inverter load current, and the error voltage and the inverter load current correspond one to one; fitting the relationship between the error voltage and the inverter load current in the multiple data groups by a fitting function to obtain the error voltage nonlinear function; and obtaining the saturated error voltage value based on the multiple data groups.

[0007] In one embodiment of the present invention, the fitting function is: ,in, is the objective function, x is the independent variable, and a, b, c, and d are the characterization coefficients of the fitting function respectively; the relationship between the error voltage and the inverter load current in multiple data groups is fitted by the fitting function to obtain the error voltage nonlinear function, including: using the spline interpolation method to fit the data of the multiple data groups to obtain four characterization coefficients a, b, c, and d, so as to obtain the error voltage nonlinear function as follows: ;in, is the error voltage caused by the nonlinear characteristics of the inverter, is the inverter load current.

[0008] In one example of the present invention, multiple data groups are obtained by applying different voltage excitations, wherein the data groups include error voltages and inverter load currents, and the error voltages and inverter load currents correspond one-to-one, including: opening one phase of the upper bridge arm of the three-phase bridge arm of the inverter and the lower bridge arm of one of the other two phases other than this phase; applying different voltage excitations to the frequency converter to obtain multiple error voltages and multiple inverter load currents; and making the error voltages and inverter load currents correspond one-to-one to obtain multiple data groups.

[0009] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the error voltage is obtained by the difference between the actual output voltage and the expected output voltage of the inverter; the saturated error voltage value and the nonlinear function of the error voltage are obtained according to the error voltage and the inverter load current, and the relationship function between the error voltage and the inverter load current is fitted by applying different voltages; in detail: by opening one phase of the upper bridge arm of the three-phase bridge arm of the inverter and the lower bridge arm of one of the other two phases other than this phase, different voltage excitations are applied to the inverter to obtain different groups of inverter nonlinear error voltages and inverter load current (It can also be expressed as the inverter corresponding current, that is, the current flowing through the inverter). In the non-saturated region of the inverter non-linear error voltage, these data sets are used to fit the inverter non-linear characteristic curve (fitting function) according to the following formula: , is the objective function (i.e. the required error voltage), x is the independent variable (i.e. the inverter load current); through the offline calibration data set , the spline interpolation method is used for data fitting (to make the interpolation result smoother), and the a, b, c, and d coefficients of the inverter nonlinear characterization function are obtained, where the number of data groups is n groups; after obtaining the a, b, c, and d coefficients of the inverter nonlinear characterization function, the error voltage nonlinear function can be obtained as: . The data is fitted by spline interpolation method, which has high precision and stability; at the same time, the nonlinear characteristics of the inverter are fitted by an offline calibration curve (that is, the error voltage nonlinear function), and then the inverter nonlinear online voltage compensation is performed. The inverter nonlinear compensation method of this application has the advantages of simple control structure, convenient implementation, and stable algorithm; the inverter nonlinear compensation method proposed in this application can achieve the function of optimizing the control performance of the inverter; and this application does not change the hardware structure of the inverter, the control structure is simple, the control parameter setting is simplified, and it is easy to implement.

[0010] In one example of the present invention, the inverter includes a nonlinear error voltage saturation region and a nonlinear error voltage unsaturation region; the inverter nonlinear compensation method also includes: in the nonlinear error voltage saturation region, using the saturated error voltage value to perform nonlinear compensation on the inverter; and / or in the nonlinear error voltage unsaturation region, using the error voltage nonlinear function to perform nonlinear compensation on the inverter.

[0011] In one embodiment of the present invention, the nonlinear compensation voltage of the inverter is: ;in, is the nonlinear compensation voltage; is the saturation error voltage value; It is the current corresponding to when the inverter reaches the nonlinear saturation error voltage.

[0012] In one embodiment of the present invention, closed-loop dead zone compensation of the inverter is realized by using the second compensation voltage signal and the output voltage of the current loop PI regulator, including: superimposing the second compensation voltage signal on the output voltage of the current loop PI regulator to form a closed-loop control; the closed-loop compensation voltage is: ;in, , and They are the a-phase compensation voltage, b-phase compensation voltage and c-phase compensation voltage in the abc coordinate system respectively; is the d-axis compensation voltage in the dq coordinate system, is the q-axis compensation voltage in the dq coordinate system; is the motor electrical angle.

[0013] On the other hand, an embodiment of the present invention also provides an inverter nonlinear compensation device, including: an acquisition module, the acquisition module is used to acquire the error voltage and the inverter load current; a first processing module, the first processing module is used to obtain the saturation error voltage value and the error voltage nonlinear function according to the error voltage and the inverter load current; a second processing module, the second processing module is used to determine the first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current; a second coordinate transformation module, the second coordinate transformation module is used to perform coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal; a third processing module, the third processing module is used to realize closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator; wherein the error voltage is the difference between the actual output voltage of the inverter and the expected output voltage.

[0014] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the inverter nonlinear compensation device in this embodiment is used to implement the inverter nonlinear compensation method as in any embodiment of the present invention, so it has all the beneficial effects of the inverter nonlinear compensation method as in any embodiment of the present invention, which will not be repeated here.

[0015] On the other hand, an embodiment of the present invention further provides an electronic device, comprising: a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein when the program or instruction is executed by the processor, the steps of the inverter nonlinear compensation method as in any one of the above embodiments are implemented.

[0016] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the electronic device in this embodiment operates the inverter nonlinear compensation method as in any embodiment of the present invention, so it has all the beneficial effects of the inverter nonlinear compensation method as in any embodiment of the present invention, which will not be repeated here.

[0017] On the other hand, an embodiment of the present invention further provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the inverter nonlinear compensation method as in any of the above embodiments are implemented.

[0018] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the readable storage medium in this embodiment is used to store the inverter nonlinear compensation method as in any embodiment of the present invention, so it has all the beneficial effects of the inverter nonlinear compensation method as in any embodiment of the present invention, which will not be repeated here.

[0019] After adopting the technical solution of the present invention, the following technical effects can be achieved:

[0020] (1) The inverter nonlinear compensation method proposed in this application can achieve the function of optimizing the inverter control performance; and this application does not change the inverter hardware structure, the control structure is simple, the control parameter setting is simplified, and it is easy to implement;

[0021] (2) The inverter nonlinear compensation method of the present application has the advantages of simple control structure, convenient implementation, and stable algorithm;

[0022] (3) The data is fitted by spline interpolation method, which has high accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A structural block diagram of a permanent magnet synchronous motor vector control system of an inverter nonlinear compensation method provided in Embodiment 1 of the present invention;

[0024] Figure 2 A flowchart of a method for inverter nonlinear compensation provided in Embodiment 1 of the present invention;

[0025] Figure 3 for Figure 1 The structure diagram of the three-phase bridge circuit of the power conversion part of the inverter;

[0026] Figure 4 The ideal PWM wave state of the inverter and the PWM wave state considering the insertion of dead zone;

[0027] Figure 5 A schematic diagram of the nonlinear characteristics of the inverter using the conventional inverter nonlinear compensation method only considering the dead zone effect;

[0028] Figure 6 A schematic diagram of the nonlinear characteristics of the inverter using the inverter nonlinear compensation method provided by the present application taking into account the dead zone influence and the influence of the tube voltage drop and the junction capacitance;

[0029] Figure 7 for Figure 2Circuit diagram of the inverter nonlinear compensation method;

[0030] Figure 8 for Figure 2 An example of inverter nonlinear compensation method is given to obtain the inverter nonlinear error voltage The three-phase bridge switch state circuit diagram;

[0031] Fig. 9 for Figure 8 Current equivalent diagram of ;

[0032] Fig.10 A schematic structural diagram of an inverter nonlinear compensation device provided in accordance with a second embodiment of the present invention;

[0033] Fig.11 A block diagram of an electronic device according to a third embodiment of the present invention;

[0034] Fig.12 A schematic structural diagram of a readable storage medium provided for the fourth embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1-speed loop regulator; 2-d-axis current loop regulator; 3-q-axis current regulator; 4-space vector regulation module; 5-power converter; 6-current sensor; 7-permanent magnet synchronous motor; 8-encoder; 9-speed and position processor; 10-first coordinate converter; 11-nonlinear compensator; 12-second coordinate converter; 100-inverter nonlinear compensation device; 101-acquisition module; 102-first processing module; 103-second processing module; 104-second coordinate conversion module; 105-third processing module; 200-electronic device; 210-memory; 211-computer program; 220-processor; 300-readable storage medium; 310-computer executable instructions. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] [Example 1]

[0039] See also Figure 2 , which is a flow chart of an inverter nonlinear compensation method provided by the first embodiment of the present invention, the inverter nonlinear compensation method comprising:

[0040] Step S100: collecting error voltage and inverter load current;

[0041] Step S200: obtaining a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current;

[0042] Step S300: determining a first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current;

[0043] Step S400: performing coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal;

[0044] Step S500: realizing closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator;

[0045] The error voltage is the difference between the actual output voltage of the inverter and the expected output voltage.

[0046] Furthermore, step S300 includes:

[0047] Step S310: obtaining a plurality of data groups by applying different voltage excitations, wherein the data groups include error voltages and inverter load currents, and the error voltages and inverter load currents correspond one to one;

[0048] Step S320: fitting the relationship between the error voltage and the inverter load current in the plurality of data groups by means of a fitting function to obtain a nonlinear function of the error voltage;

[0049] Step S330: obtaining a saturation error voltage value according to a plurality of data sets.

[0050] Furthermore, the fitting function is: ,in, is the objective function, x is the independent variable, a, b, c, d are the characterization coefficients of the fitting function respectively; step S320 includes:

[0051] The spline interpolation method is used to fit multiple data sets and obtain four characterization coefficients a, b, c, and d, thereby obtaining the error voltage nonlinear function as follows: ;

[0052] in, is the error voltage caused by the nonlinear characteristics of the inverter, is the inverter load current.

[0053] Further, step S310 includes:

[0054] Open one phase of the upper bridge arm of the three-phase bridge arm of the inverter and the lower bridge arm of one of the other two phases other than the upper bridge arm of the three-phase bridge arm of the inverter;

[0055] Applying different voltage excitations to the inverter to obtain multiple error voltages and multiple inverter load currents;

[0056] The error voltage and the inverter load current are matched one by one to obtain multiple data groups.

[0057] In a specific embodiment, see Figure 1 The present invention is a structural block diagram of a permanent magnet synchronous motor vector control system of an inverter nonlinear compensation method, wherein the inverter nonlinear compensation method includes a permanent magnet synchronous motor 7 vector control system and an inverter nonlinear detection and compensation part, wherein the permanent magnet synchronous motor 7 vector control system includes a target speed given instruction, a speed loop regulator 1, a d-axis current loop regulator 2, a q-axis current regulator 3, a space vector regulation module 4, a power converter 5, a current sensor 6, a permanent magnet synchronous motor 7, an encoder 8, a speed and position processor 9, a first coordinate converter 10, a nonlinear compensator 11 and a second coordinate converter 12; the speed loop regulator 1 is used to adjust the motor speed to follow a given speed, that is, to adjust a given target speed; the d-axis current loop regulator 2 is used to adjust the feedback d current to follow a given d current, and the q-axis current regulator 3 is used to adjust the feedback q current to follow a given q current, that is, the d-axis current loop regulator 2 and the q-axis current regulator 3 adjust the target current; the space vector The regulation module 4 is used for inverter PWM command output; the power converter 5 is used for power energy conversion; the current sensor 6 is used for motor current collection; the encoder 8 is used for motor speed and position detection; the speed and position processor 9 is used for processing the motor speed and position signals; the first coordinate converter 10 is used to convert the motor three-phase abc coordinate system current into the dq coordinate system current; the nonlinear compensator 11 is used for inverter nonlinear compensation (that is, to calculate and compensate the error voltage caused by the inverter nonlinearity), the nonlinear compensator 11 includes an offline inverter nonlinear error voltage curve fitting function and an online inverter nonlinear error voltage calculation function, and the inverter nonlinear compensator 11 computing part includes an inverter nonlinear feature offline calibration part and an inverter nonlinear online voltage compensation part; the second coordinate converter 12 is used to convert the abc coordinate system compensation voltage into the dq coordinate system compensation voltage, and superimpose it on the output of the current regulator to form a closed-loop control.

[0058] Specifically, the error voltage is obtained by the difference between the actual output voltage and the expected output voltage of the inverter; the saturated error voltage value and the nonlinear function of the error voltage are obtained according to the error voltage and the inverter load current, and the relationship function between the error voltage and the inverter load current is fitted by applying different voltages; in detail: by opening one phase of the upper bridge arm of the three-phase bridge arm of the inverter and the lower bridge arm of one of the other two phases other than this phase, different voltage excitations are applied to the inverter to obtain different groups of inverter nonlinear error voltages and inverter load current (It can also be expressed as the inverter corresponding current, that is, the current flowing through the inverter). In the non-saturated region of the inverter non-linear error voltage, these data sets are used to fit the inverter non-linear characteristic curve (fitting function) according to the following formula: , is the objective function (i.e. the required error voltage), x is the independent variable (i.e. the inverter load current), this formula only leads to a unified form of compensation voltage function; through the offline calibration data set , the spline interpolation method is used for data fitting (to make the interpolation result smoother), and the a, b, c, and d coefficients of the inverter nonlinear characterization function are obtained, where the number of data groups is n groups; after obtaining the a, b, c, and d coefficients of the inverter nonlinear characterization function, the error voltage nonlinear function can be obtained as: . The data is fitted by spline interpolation method, which has high precision and stability; at the same time, the nonlinear characteristics of the inverter are fitted by an offline calibration curve (that is, the error voltage nonlinear function), and then the inverter nonlinear online voltage compensation is performed. The inverter nonlinear compensation method of this application has the advantages of simple control structure, convenient implementation, and stable algorithm; the inverter nonlinear compensation method proposed in this application can achieve the function of optimizing the control performance of the inverter; and this application does not change the hardware structure of the inverter, the control structure is simple, the control parameter setting is simplified, and it is easy to implement.

[0059] Figure 7 The circuit diagram of the inverter nonlinear compensation method of the present invention is shown in FIG. is the inverter error voltage. The inverter nonlinear compensation method takes the error voltage as an objective function of the inverter current and fits the error voltage caused by the inverter nonlinearity through the following formula: .

[0060] Figure 8 The nonlinear error voltage of the inverter is obtained by exemplifying the nonlinear compensation method of the inverter of the present invention. The three-phase bridge switch state circuit diagram of the present invention is as follows. The method of the present invention obtains the nonlinear error voltage function of the inverter by opening the upper bridge arm switch of the inverter A phase and the lower bridge arm switch of the inverter B phase.

[0061] Fig. 9 for Figure 8 The current equivalent diagram is shown by applying a voltage To obtain the error voltage , the present invention assumes that the nonlinear error voltages of the inverter switches are all equal, because the error voltage can be obtained by the following formula: By applying different sets of voltages and sampling the inverter response current when different sets of voltages are applied, the error voltage under different currents is obtained. Through these data sets, the nonlinear characteristic function of the inverter can be fitted to obtain the coefficients a, b, c, and d in the fitting function.

[0062] Furthermore, the inverter includes a nonlinear error voltage saturation region and a nonlinear error voltage unsaturation region; the inverter nonlinear compensation method also includes:

[0063] In the nonlinear error voltage saturation region, using the saturated error voltage value to perform nonlinear compensation on the inverter; and / or

[0064] In the non-saturation region of the non-linear error voltage, the non-linear function of the error voltage is used to perform non-linear compensation on the inverter.

[0065] Furthermore, the nonlinear compensation voltage of the inverter is: ;

[0066] in, is the nonlinear compensation voltage; is the saturation error voltage value; It is the current corresponding to when the inverter reaches the nonlinear saturation error voltage.

[0067] Furthermore, closed-loop dead zone compensation of the inverter is realized by using the second compensation voltage signal and the output voltage of the current loop PI regulator, including:

[0068] The second compensation voltage signal is superimposed on the output voltage of the current loop PI regulator to form a closed-loop control;

[0069] The closed-loop compensation voltage is:

[0070] ;

[0071] in, , and They are the a-phase compensation voltage, b-phase compensation voltage and c-phase compensation voltage in the abc coordinate system respectively; is the d-axis compensation voltage in the dq coordinate system, is the q-axis compensation voltage in the dq coordinate system; is the motor electrical angle.

[0072] Specifically, Figure 5 This is a schematic diagram of the inverter nonlinear characteristics that only considers the dead time effect using the conventional inverter nonlinear compensation method. By distinguishing the current polarity of the inverter, the inverter error current caused by the dead time is compensated. Since the junction capacitance and the on-state voltage drop factors in the inverter nonlinearity are not considered, this method has a poor compensation effect. Figure 6 A schematic diagram of the inverter nonlinear characteristics that consider the dead zone influence and the tube voltage drop and junction capacitance influence using the inverter nonlinear compensation method provided by the present application. The present application simultaneously considers the inverter nonlinear characteristics caused by the inverter junction capacitance, on-state voltage drop and dead zone time. The method of the present application calculates the error voltage as a nonlinear target value, and then compensates the error voltage in the closed-loop system.

[0073] formula It shows that in the non-saturated region of the inverter non-linear error voltage, the fitting function of the offline detection proposed by the present invention is used to compensate the inverter error voltage, and in the saturated region of the inverter non-linear error voltage, the saturated error voltage detected offline is directly used for compensation.

[0074] After the error saturation voltage is obtained, the second coordinate converter 12 is used to convert the compensation voltage of the abc coordinate system into the compensation voltage of the dq coordinate system, and superimpose it on the output of the current regulator to form a closed-loop control, wherein the closed-loop compensation voltage is: ;in, , and is the first compensation voltage signal in the abc coordinate system, and is the second compensation voltage signal in the dq coordinate system; and It is superimposed on the output of the d-axis current loop regulator and the q-axis current regulator to form a closed-loop control, thereby achieving the effect of inverter nonlinear compensation.

[0075] Preferably, Figure 3 It is a structural diagram of a three-phase bridge circuit of the power conversion part of the inverter. In the present invention, the current flowing to the motor is specified as positive current, while the current flowing out of the motor is specified as negative current.

[0076] Figure 4 The ideal PWM wave state of the inverter and the PWM wave state considering the insertion of dead zone. Figure 4 (a) shows the ideal PWM wave state of the inverter, with symmetric PWM of the upper and lower bridge arms; Figure 4(b) shows the PWM wave state of the inverter with dead zone inserted. The PWM of the upper and lower bridge arms is asymmetric. In the figure, the dotted part is the inserted dead zone time. During this period of time, the upper and lower bridge arms are in the off state. After the dead zone is inserted, the nonlinear characteristics of the inverter dead zone are related to the direction of the motor current flow.

[0077] [Example 2]

[0078] See also Fig.10 This embodiment also provides an inverter nonlinear compensation device 100, including: an acquisition module 101, the acquisition module 101 is used to acquire the error voltage and the inverter load current; a first processing module 102, the first processing module 102 is used to obtain a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current; a second processing module 103, the second processing module 103 is used to determine a first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current; a second coordinate transformation module 104, the second coordinate transformation module 104 is used to perform coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal; a third processing module 105, the third processing module 105 is used to realize closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator; wherein the error voltage is the difference between the actual output voltage of the inverter and the expected output voltage.

[0079] In a specific embodiment, the acquisition module 101, the first processing module 102, the second processing module 103, the second coordinate conversion module 104 and the third processing module 105 of the inverter nonlinear compensation device 100 cooperate to implement the inverter nonlinear compensation method of the first embodiment above, which will not be repeated here.

[0080] [Example 3]

[0081] See also Fig.11 This embodiment provides a structural schematic diagram of an electronic device 200. The electronic device 200, for example, includes a processor 220 and a memory 210 electrically connected to the processor 220. The memory 210 stores a computer program 211. The processor 220 loads the computer program 211 to implement the inverter nonlinear compensation method as in the first embodiment.

[0082] [Example 4]

[0083] See also Fig.12 This embodiment also provides a readable storage medium 300, which stores computer executable instructions 310. When the computer executable instructions 310 are read and executed by the processor, the electronic device where the readable storage medium 300 is located is controlled to implement the inverter nonlinear compensation method in the first embodiment.

[0084] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are only illustrative. For example, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0085] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned readable storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for inverter nonlinear compensation, comprising a permanent magnet synchronous motor (7) vector control system and an inverter nonlinear detection and compensation part, wherein the permanent magnet synchronous motor (7) vector control system comprises a target speed given instruction, a speed loop regulator (1), a d-axis current loop regulator (2), a q-axis current regulator (3), a space vector regulation module (4), a power converter (5), a current sensor (6), a permanent magnet synchronous motor (7), an encoder (8), a speed and position processor (9), a first coordinate converter (10), a nonlinear compensator (11) and a second coordinate converter (12), wherein the nonlinear compensator (11) comprises an offline inverter nonlinear error voltage curve fitting function and an online inverter nonlinear error voltage calculation function, wherein the inverter nonlinear compensator (11) computing part comprises an inverter nonlinear characteristic offline calibration part and an inverter nonlinear online voltage compensation part ... The inverter nonlinear compensation method comprises: Collect error voltage and inverter load current; Obtaining a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current; Determining a first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current; Performing coordinate transformation on the first compensation voltage signal to obtain a second compensation voltage signal; Implementing closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator; Wherein, the error voltage is the difference between the actual output voltage and the expected output voltage of the inverter; The step of obtaining a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current includes: By applying different voltage excitations, a plurality of data groups are obtained, wherein the data group includes the error voltage and the inverter load current, and the error voltage and the inverter load current correspond one to one; Fitting the relationship between the error voltage and the inverter load current in the plurality of data groups by means of a fitting function to obtain a nonlinear function of the error voltage; Acquire the saturation error voltage value according to the plurality of data groups; wherein the error voltage is calculated as a nonlinear target value, and then the error voltage is compensated in a closed-loop system; The fitting function is: ;in, is the objective function, x is the independent variable, a, b, c, d are the characterization coefficients of the fitting function respectively; The step of fitting the relationship between the error voltage and the inverter load current in the plurality of data groups by means of a fitting function to obtain a nonlinear function of the error voltage includes: The spline interpolation method is used to perform data fitting on the plurality of data groups to obtain the four characterization coefficients a, b, c, and d, thereby obtaining the error voltage nonlinear function as follows: ； in, is the error voltage caused by the nonlinear characteristics of the inverter, is the inverter load current; By applying voltage To obtain the error voltage , the present invention assumes that the nonlinear error voltages of the inverter switches are all equal, because the error voltage can be obtained by the following formula: By applying different sets of voltages and sampling the inverter response current when different sets of voltages are applied, the error voltage under different currents is obtained. Through these data sets, the nonlinear characteristic function of the inverter can be fitted to obtain the coefficients a, b, c, and d in the fitting function.

2. The inverter nonlinear compensation method according to claim 1, characterized in that: The method of applying different voltage excitations to obtain a plurality of data groups, wherein the data group includes the error voltage and the inverter load current, and the error voltage and the inverter load current correspond one to one, including: Opening one phase of the upper bridge arm of the three-phase bridge arm of the inverter and the lower bridge arm of one of the other two phases other than the upper bridge arm of the three-phase bridge arm of the inverter; Applying different voltage excitations to the frequency converter to obtain a plurality of error voltages and a plurality of inverter load currents; The error voltage and the inverter load current are matched one by one to obtain a plurality of the data groups.

3. The inverter nonlinear compensation method according to claim 1, characterized in that: The inverter includes a nonlinear error voltage saturation region and a nonlinear error voltage unsaturation region; The inverter nonlinear compensation method further includes: In the nonlinear error voltage saturation region, using the saturated error voltage value to perform nonlinear compensation on the inverter; and / or In the non-saturation region of the non-linear error voltage, the non-linear function of the error voltage is used to perform non-linear compensation on the inverter.

4. The inverter nonlinear compensation method according to claim 3, characterized in that: The nonlinear compensation voltage of the inverter is: ; in, is the nonlinear compensation voltage; is the saturation error voltage value; is the current corresponding to when the inverter reaches the nonlinear saturation error voltage.

5. The inverter nonlinear compensation method according to claim 4, characterized in that: The method of realizing closed-loop dead zone compensation of the inverter by using the second compensation voltage signal and the output voltage of the current loop PI regulator includes: superimposing the second compensation voltage signal to the output voltage of the current loop PI regulator to form a closed-loop control; The closed-loop compensation voltage is: ； in, , and They are the a-phase compensation voltage, b-phase compensation voltage and c-phase compensation voltage in the abc coordinate system respectively; is the d-axis compensation voltage in the dq coordinate system, is the q-axis compensation voltage in the dq coordinate system; is the motor electrical angle.

6. An inverter nonlinear compensation device, characterized in that: The inverter nonlinear compensation device applies the inverter nonlinear compensation method according to any one of claims 1 to 5, and the inverter nonlinear compensation device comprises: A collection module, the collection module is used to collect error voltage and inverter load current; A first processing module, the first processing module is used to obtain a saturated error voltage value and an error voltage nonlinear function according to the error voltage and the inverter load current; a second processing module, the second processing module being used to determine a first compensation voltage signal of the inverter according to the error voltage nonlinear function and the motor phase current; A second coordinate conversion module, the second coordinate conversion module is used to perform coordinate conversion on the first compensation voltage signal to obtain a second compensation voltage signal; a third processing module, the third processing module being used to realize closed-loop dead zone compensation of the inverter through the second compensation voltage signal and the output voltage of the current loop PI regulator; The error voltage is the difference between the actual output voltage and the expected output voltage of the inverter.

7. An electronic device, characterized in that: The electronic device comprises: a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the inverter nonlinear compensation method as claimed in any one of claims 1 to 5.

8. A readable storage medium, characterized in that: The readable storage medium stores a program or an instruction, and when the program or the instruction is executed by the processor, the steps of the inverter nonlinear compensation method as described in any one of claims 1 to 5 are implemented.

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