Motor parameter identification method, device, storage medium and electronic equipment

Abstract

The present invention discloses a motor parameter identification method, device, storage medium and electronic device, wherein the motor parameter identification method includes: obtaining the voltage value and current value of each phase based on the mode of applying DC voltage to the motor winding; determining the stator resistance of each phase according to the voltage value and current value of each phase; determining the stator resistance of the motor according to the stator resistance of each phase, and determining the output voltage deviation of each phase according to the voltage value, current value and stator resistance of each phase, and determining the output phase voltage deviation of the inverter according to the output voltage deviation of each phase. This method can not only realize the identification of the stator resistance of the motor, but also can identify and obtain the output phase voltage deviation of the inverter, and then realize the phase voltage balance control of the inverter based on the deviation.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a motor parameter identification method, device, storage medium and electronic equipment. Background Art

[0002] In asynchronous motor vector control, motor parameters such as stator resistance, rotor resistance, leakage inductance, mutual inductance, and rotor time constant are usually required. However, such parameters cannot be found on the motor nameplate. Even many motor manufacturers do not measure and calibrate these parameters before the motor leaves the factory. Therefore, in engineering, offline static identification methods or online identification methods are generally used to identify these parameters. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the first purpose of the present invention is to propose a motor parameter identification method, which can not only realize the identification of the motor stator resistance, but also can identify and obtain the inverter output phase voltage deviation, and then realize the inverter phase voltage balance control based on the deviation.

[0004] A second object of the present invention is to provide a computer-readable storage medium.

[0005] A third objective of the present invention is to provide an electronic device.

[0006] A fourth objective of the present invention is to provide a motor parameter identification device.

[0007] To achieve the above-mentioned purpose, the first aspect of the present invention proposes a motor parameter identification method, including: obtaining the voltage value and current value of each phase based on the method of applying DC voltage to the motor winding; determining the stator resistance of each phase according to the voltage value and current value of each phase; determining the stator resistance of the motor according to the stator resistance of each phase, and determining the output voltage deviation of each phase according to the voltage value, current value and stator resistance of each phase, and determining the output phase voltage deviation of the inverter according to the output voltage deviation of each phase.

[0008] According to the motor parameter identification method of the embodiment of the present invention, based on the way of applying DC voltage to the motor winding, the voltage value and current value of each phase are obtained, and the stator resistance of each phase is determined according to the voltage value and current value of each phase, and the stator resistance of the motor is determined according to the stator resistance of each phase, and the output voltage deviation of each phase is determined according to the voltage value, current value and stator resistance of each phase, and the output phase voltage deviation of the inverter is determined according to the output voltage deviation of each phase. Not only can the stator resistance of the motor be identified, but also the output phase voltage deviation of the inverter can be identified and obtained, and then the phase voltage balance control of the inverter can be realized based on the deviation.

[0009] According to one embodiment of the present invention, after the inverter stops outputting, the method further includes: obtaining each back EMF of the motor; determining the back EMF modulus according to each back EMF of the motor, and determining the rotor time constant according to the back EMF modulus.

[0010] According to one embodiment of the present invention, determining the rotor time constant based on the back-EMF modulus value includes: obtaining the back-EMF modulus value determined at the first back-EMF sampling moment, and obtaining the back-EMF modulus value determined at the Nth back-EMF sampling moment, wherein the back-EMF modulus value determined at the Nth back-EMF sampling moment is less than the product of the first preset coefficient and the back-EMF modulus value determined at the first back-EMF sampling moment; determining the rotor time constant based on the back-EMF modulus value determined at the first back-EMF sampling moment, the back-EMF modulus value determined at the Nth back-EMF sampling moment, and N back-EMF sampling periods, wherein N is an integer greater than 1.

[0011] According to one embodiment of the present invention, the rotor time constant is calculated according to the following formula:

[0012]

[0013] Among them, T r is the rotor time constant, T s is the back EMF sampling period, E mod0 is the back EMF modulus value determined at the first back EMF sampling moment, E modN It is the back-EMF modulus value determined at the Nth back-EMF sampling moment.

[0014] According to one embodiment of the present invention, based on the method of applying DC voltage to the motor winding, the voltage value of each phase and the current value of each phase are obtained, including: controlling any one phase output of the inverter to be open, and controlling the remaining two phases of the inverter to apply DC voltage to the corresponding motor winding, and adjusting the output voltage duty cycle of the inverter so that the output current of the inverter reaches a first target current and a second target current, respectively; determining a first output voltage duty cycle when the output current of the inverter reaches the first target current, and determining a second output voltage duty cycle when the output current of the inverter reaches the second target current, and determining a first phase voltage value and a second phase voltage value of at least one phase of the remaining two phases according to the first output voltage duty cycle, the second output voltage duty cycle and the bus voltage of the inverter; when the output current of the inverter reaches the first target current and the second target current, respectively, obtaining a first phase current value and a second phase current value of at least one phase of the remaining two phases.

[0015] According to one embodiment of the present invention, the stator resistance of each phase is determined according to the voltage value of each phase and the current value of each phase, including: determining the voltage difference between the first phase voltage value and the second phase voltage value of any phase, and determining the current difference between the first phase current value and the second phase current value of the phase, and determining the stator resistance of the phase according to the voltage difference and the current difference.

[0016] According to one embodiment of the present invention, the output voltage deviation of any phase is calculated according to the following formula:

[0017]

[0018] Among them, ΔU x is the output voltage deviation of any phase, are the first phase voltage value and the second phase voltage value of the phase, I x1 ,I x2 are the first phase current value and the second phase current value of the phase respectively, R sx is the stator resistance of this phase.

[0019] According to one embodiment of the present invention, after determining the output phase voltage deviation of the inverter, the method also includes: controlling any one phase output of the inverter to be open-circuited, and controlling the remaining two phases of the inverter to apply AC excitation current to the corresponding motor windings to obtain the reactive power and current effective value of at least one phase of the remaining two phases; determining the leakage inductance of the phase according to the reactive power and current effective value of any one phase and the current frequency of the AC excitation current; determining the motor stator leakage inductance and the motor rotor leakage inductance according to the leakage inductance of each phase.

[0020] According to one embodiment of the present invention, after determining the stator leakage inductance and the rotor leakage inductance of the motor, the method also includes: using the VF control mode to drag the motor to a preset frequency for operation, and determining the current reactive power and the current effective current value according to the voltage value of each phase and the current value of each phase, and determining the motor stator inductance and / or the motor rotor inductance according to the current reactive power and the current effective current value; determining the motor mutual inductance according to the motor stator inductance and / or the motor rotor inductance, and the motor stator leakage inductance and / or the motor rotor leakage inductance.

[0021] According to one embodiment of the present invention, after determining the motor mutual inductance, the method further includes: controlling the inverter to stop outputting, and determining the motor rotor resistance according to the motor rotor inductance and the rotor time constant determined after the inverter stops outputting.

[0022] To achieve the above-mentioned purpose, a second aspect of the present invention provides a computer-readable storage medium on which a motor parameter identification program is stored. When the motor parameter identification program is executed by a processor, the above-mentioned motor parameter identification method is implemented.

[0023] According to the computer-readable storage medium of an embodiment of the present invention, by executing the aforementioned motor parameter identification method through a processor, not only the motor stator resistance can be identified, but also the inverter output phase voltage deviation can be identified, and then the inverter phase voltage balance control can be achieved based on the deviation.

[0024] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, including a memory, a processor, and a motor parameter identification program stored in the memory and executable on the processor. When the processor executes the motor parameter identification program, it implements the motor parameter identification method described above.

[0025] According to the electronic device of the embodiment of the present invention, by executing the aforementioned motor parameter identification method through the processor, not only the stator resistance of the motor can be identified, but also the output phase voltage deviation of the inverter can be identified, and then the phase voltage balance control of the inverter can be realized based on the deviation.

[0026] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a motor parameter identification device, including: an acquisition module, which acquires the voltage value of each phase and the current value of each phase based on the method of applying DC voltage to the motor winding; an identification module, which is used to determine the stator resistance of each phase according to the voltage value of each phase and the current value of each phase, and determine the stator resistance of the motor according to the stator resistance of each phase, and determine the output voltage deviation of each phase according to the voltage value of each phase, the current value of each phase and the stator resistance of each phase, and determine the output phase voltage deviation of the inverter according to the output voltage deviation of each phase.

[0027] According to the motor parameter identification device of the embodiment of the present invention, the acquisition module obtains the voltage value and the current value of each phase based on the way of applying DC voltage to the motor winding, and determines the stator resistance of each phase according to the voltage value and the current value of each phase through the identification module, determines the stator resistance of the motor according to the stator resistance of each phase, determines the output voltage deviation of each phase according to the voltage value, current value and stator resistance of each phase, and determines the output phase voltage deviation of the inverter according to the output voltage deviation of each phase. Not only can the stator resistance of the motor be identified, but also the output phase voltage deviation of the inverter can be identified and obtained, and then the phase voltage balance control of the inverter can be realized based on the deviation.

[0028] Additional aspects and advantages 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

[0029] Figure 1 is a flow chart of a motor parameter identification method according to an embodiment of the present invention;

[0030] Figure 2 A flowchart for obtaining a voltage value of each phase and a current value of each phase according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of applying a DC voltage to a motor according to an embodiment of the present invention;

[0032] Figure 4A flowchart of obtaining the stator leakage inductance and the rotor leakage inductance of a motor according to an embodiment of the present invention;

[0033] Figure 5 is a T-type equivalent circuit diagram of a motor according to an embodiment of the present invention;

[0034] Figure 6 for Figure 5 A simplified diagram of the T-type equivalent circuit shown;

[0035] Figure 7 A flowchart of obtaining the stator inductance, rotor inductance and mutual inductance of a motor according to an embodiment of the present invention;

[0036] Figure 8 for Figure 5 Another simplified diagram of the T-type equivalent circuit shown;

[0037] Fig. 9 A flowchart of obtaining a rotor time constant according to an embodiment of the present invention;

[0038] Fig.10 is a schematic structural diagram of an electronic device according to an embodiment of the present invention;

[0039] Fig.11 Schematic diagram of the structure of a motor parameter identification device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0041] Figure 1 The figure is a flow chart of a motor parameter identification method according to an embodiment of the present invention.

[0042] refer to Figure 1 As shown, the motor parameter identification method may include the following steps:

[0043] S11, based on the method of applying DC voltage to the motor winding, obtain the voltage value of each phase and the current value of each phase.

[0044] S12, determining the stator resistance of each phase according to the voltage value of each phase and the current value of each phase.

[0045] It should be noted that the present application does not limit the type of motor, as long as the motor parameter identification method of the present application is used to identify the motor parameters. For ease of description, an asynchronous motor is used as an example for illustration.

[0046] Specifically, the inverter can identify the parameters of the asynchronous motor, such as the stator resistance of the motor. At this time, the inverter can apply a DC voltage to different line windings of the motor and obtain the voltage value and current value of each phase of the motor, and then obtain the stator resistance of each phase of the motor based on the voltage value and current value of each phase.

[0047] In some embodiments, Figure 2 As shown, based on the way of applying DC voltage to the motor winding, the voltage value of each phase and the current value of each phase are obtained, including:

[0048] S21, controlling any one phase output of the inverter to be open-circuited, and controlling the remaining two phases of the inverter to apply a DC voltage to the corresponding motor windings, and adjusting the output voltage duty cycle of the inverter so that the output current of the inverter reaches the first target current and the second target current respectively.

[0049] For example, the inverter's C phase output can be controlled to be open circuited, and the inverter's A phase and B phase can be controlled to apply DC voltage to the corresponding windings. The equivalent circuit is as follows: Figure 3 As shown, from Figure 3 It can be seen that it is equivalent to the C-phase winding of the motor being open-circuited, and a DC voltage DC is applied between the A-phase winding and the B-phase winding. Then, the output voltage duty cycle of the inverter is gradually adjusted to adjust the output current of the inverter. For example, the amplitude of the output current is controlled based on adjustment methods such as PI (proportional integral) or PID (proportional integral differential), and the output current of the inverter is collected in real time until the output current reaches the target current. It can be understood that at this time, the output current of the inverter is also the A-phase current of the inverter. Therefore, the A-phase current of the inverter, that is, the output current of the inverter, can be obtained by sampling the sampling resistor connected in series to the A-phase of the inverter.

[0050] It should be noted that in order to ensure the accuracy of the identification of the stator resistance of each phase of the motor, when determining the stator resistance of each phase of the motor based on the output voltage of each phase and the output current of each phase, it can be calculated based on the voltage change and the current change to reduce the sampling error. Therefore, the output current of the inverter can be adjusted to reach different target currents by adjusting the output voltage duty cycle of the inverter, such as the first target current I set1 and the second target current I set2 Optionally, the first target current is 0.9 times the rated current of the motor I e , the second target current I set2 0.6 times the motor rated current I e , of course it is not limited to this.

[0051] S22, determining a first output voltage duty cycle when the output current of the inverter reaches a first target current, determining a second output voltage duty cycle when the output current of the inverter reaches a second target current, and determining a first phase voltage value and a second phase voltage value of at least one phase of the remaining two phases based on the first output voltage duty cycle, the second output voltage duty cycle and the bus voltage of the inverter.

[0052] S23, when the output current of the inverter reaches the first target current and the second target current respectively, obtaining a first phase current value and a second phase current value of at least one phase of the remaining two phases.

[0053] For example, Figure 3 Take the example shown as an example. When the output current of the inverter reaches the first target current I set1 When the current output voltage duty cycle (i.e., the first output voltage duty cycle d1) is maintained unchanged, that is, the output current of the inverter is maintained unchanged. At this time, the first output voltage duty cycle d1 and the DC bus voltage U dc (Can be sampled) Calculate the first phase voltage value of phase A Right now At the same time, the first phase current I of phase A can be obtained by sampling the sampling resistor A1 Similarly, when the output current of the inverter reaches the second target current I set2 When the current output voltage duty cycle (i.e., the second output voltage duty cycle d2) is maintained unchanged, that is, the output current of the inverter is maintained unchanged. At this time, the second output voltage duty cycle d2 and the DC bus voltage U dc Calculate the second phase voltage value of phase A Right now At the same time, the second phase current I of phase A can be obtained by sampling the sampling resistor A2 .

[0054] It should be noted that when sampling to obtain the first phase current I of phase A A1 and the second phase current I A2 When , it can be obtained by averaging multiple samples, thereby further reducing the sampling error and improving the accuracy of parameter identification. For example, when the output current of the inverter reaches the first target current I set1 When the phase current of phase A can be sampled continuously for n times, it is recorded as I A1i , and the first phase current I is calculated by the formula A1 ,Right now Where i = 0, 1, ..., n; Similarly, when the output current of the inverter reaches the second target current I set2 When the phase current of phase A can be sampled continuously for n times, it is recorded as I A2i The second phase current I is calculated by the formula A2,Right now

[0055] Thus, the voltage value and current value of phase A can be obtained. Based on the same method, the voltage value and current value of phase B, as well as the voltage value and current value of phase C can be obtained, which will not be described in detail here.

[0056] After obtaining the voltage value and current value of each phase, the stator resistance of each phase can be calculated based on the voltage value and current value of each phase. As an implementation method, the stator resistance of each phase is determined according to the voltage value and current value of each phase, including: determining the voltage difference between the first phase voltage value and the second phase voltage value of any phase, and determining the current difference between the first phase current value and the second phase current value of the phase, and determining the stator resistance of the phase according to the voltage difference and the current difference.

[0057] For example, Figure 3 Take the example shown as an example. After obtaining the first phase voltage value of phase A Second phase voltage value The first phase current I A1 and the second phase current I A2 After that, based on the first phase voltage value Second phase voltage value The first phase current I A1 and the second phase current I A2 Calculate the stator resistance R of phase A sA , that is, the A-phase stator resistance of the motor Based on the same method, the motor's B-phase stator resistance R can be obtained. sB and C phase stator resistance R sC .

[0058] S13, determining the stator resistance of the motor according to the stator resistance of each phase, determining the output voltage deviation of each phase according to the voltage value of each phase, the current value of each phase and the stator resistance of each phase, and determining the output phase voltage deviation of the inverter according to the output voltage deviation of each phase.

[0059] Specifically, after obtaining the stator resistance of each phase of the motor, the motor stator resistance R can be calculated based on the stator resistance of each phase. s , that is, the motor stator resistance

[0060] Furthermore, after obtaining the stator resistance of each phase of the motor, the output voltage deviation of each phase can be calculated according to the stator resistance of each phase of the motor, the voltage value of each phase and the current value of each phase. As an implementation method, the output voltage deviation of any phase is calculated according to the following formula:

[0061]

[0062] Among them, ΔUx is the output voltage deviation of any phase, are the first phase voltage value and the second phase voltage value of the phase, I x1 ,I x2 are the first phase current value and the second phase current value of the phase respectively, R sx is the stator resistance of this phase.

[0063] For example, the output voltage deviation of phase A is Similarly, the output voltage deviation of phase B and phase C can be obtained. Then, the inverter output phase voltage deviation U is calculated based on the output voltage deviation of phase A, phase B and phase C. bias ,Right now Among them, ΔU A , ΔU B and ΔU C They are the output voltage deviations of phase A, phase B and phase C respectively.

[0064] In the above embodiment, by applying a DC voltage to the motor winding, obtaining a voltage value and a current value for each phase, determining a stator resistance for each phase according to the voltage value and the current value for each phase, determining the stator resistance of the motor according to the stator resistance for each phase, determining an output voltage deviation for each phase according to the voltage value, the current value and the stator resistance for each phase, and determining an output phase voltage deviation of the inverter according to the output voltage deviation for each phase, not only the stator resistance of the motor can be identified, but also the output phase voltage deviation of the inverter can be identified, and then the phase voltage balance control of the inverter can be realized based on the deviation; when obtaining the stator resistance for each phase, the voltage value for each phase is obtained based on the duty cycle and the DC bus voltage, and the current value for each phase is obtained by sampling when the output current of the inverter reaches a certain value, rather than directly sampling the output voltage and output current. Compared with the method of directly sampling the output voltage and the output current to identify the parameters of the motor, the identification result is more accurate. The reason is that when directly sampling the output voltage and the output current to identify the parameters of the motor, especially in the offline static identification process, since it is necessary to output AC and DC voltages, but the motor is not rotating at this time, there is no induced electromotive force, the output voltage of the inverter is very low, and the dead time of the inverter, the tube voltage drop, and the system control signal error voltage account for a relatively large proportion. For medium and high voltage frequency conversion systems with complex topological structures, the system hardware parameters are complex and have a certain degree of dispersion, which can easily cause poor consistency and stability of the identification results. The present application is based on the output current reaching a certain value, and the output voltage is obtained based on the DC bus voltage, thereby solving the problem of large error influence in complex topological systems and improving the identification accuracy.

[0065] In some embodiments, Figure 4 As shown, after determining the inverter output phase voltage deviation, the method further includes:

[0066] S31, controlling any one phase output of the inverter to be open-circuited, and controlling the remaining two phases of the inverter to apply AC excitation current to the corresponding motor windings, so as to obtain the reactive power and current effective value of at least one phase of the remaining two phases.

[0067] Specifically, the symmetrical T-type equivalent circuit of the asynchronous motor is as follows Figure 5 As shown, in Figure 5 In, R s Indicates the motor stator resistance, L s Represents the motor stator leakage inductance, R r Indicates the motor rotor resistance, L r Indicates the motor rotor leakage inductance, L m represents the mutual inductance of the motor, When an AC excitation current with an excitation frequency equal to the rated frequency of the motor is applied to the motor winding, the excitation impedance is much larger than the rotor circuit impedance, so it can be assumed that the excitation circuit is open and the iron loss is ignored. Then the equivalent circuit of the asynchronous motor can be simplified to Figure 6 The circuit shown.

[0068] When identifying the leakage inductance of the motor, the inverter's C phase output can be controlled to be open circuited, and the inverter's A phase and B phase can be controlled to apply an AC excitation current, such as a single-phase sine wave, to the corresponding winding, and the effective value of the AC excitation current can be stabilized at a certain value, such as the motor rated current I e 80% to 90% of the rated frequency of the motor, and the frequency is controlled at a certain value, such as 90% of the rated frequency of the motor. At this time, the voltage across the A-phase winding is a single-phase sinusoidal voltage. Then, the current value of the A-phase winding, that is, the A-phase current value, is sampled, and the voltage value of the A-phase winding, that is, the A-phase voltage value, is obtained, and then the effective current value and reactive power of the A-phase are calculated based on the current value, voltage value, sampling frequency, and current frequency of the AC excitation current. It should be noted that the A-phase voltage value can be obtained by calculation or sampling. As an implementation method, the effective current value of the A-phase can be calculated by the following formula:

[0069]

[0070] Among them, I evA is the effective value of the current of phase A, I evAj is the jth A-phase current value, M is the number of samples of the A-phase current value, which can be calculated based on the sampling frequency f c And the current frequency f0 of the AC excitation current is determined, for example, M = M0*f c / f0, M0 is the preset coefficient, such as M0≥4.

[0071] The reactive power of phase A can be calculated using the following formula:

[0072]

[0073] Among them, U evA is the effective value of the voltage of phase A, U evAj is the jth A-phase voltage value, and the A-phase voltage value corresponds to the A-phase current value one by one, P evA is the active power of phase A, S evA is the apparent power of phase A, Q evA is the reactive power of phase A.

[0074] Based on the same method, the effective value of the current and the reactive power of the B phase, as well as the effective value of the current and the reactive power of the C phase can be obtained, which will not be described in detail here.

[0075] S32, determining the leakage inductance of any phase according to the reactive power and the effective value of the current of the phase and the current frequency of the AC excitation current.

[0076] Specifically, after obtaining the effective value of the current and reactive power of phase A, the leakage inductance of phase A can be calculated. The leakage inductance of phase A includes the stator leakage inductance of phase A and the rotor leakage inductance of phase A. Usually, the stator leakage inductance is equal to the rotor leakage inductance, so the leakage inductance of phase A can be calculated by the following formula:

[0077]

[0078] Among them, L A is the leakage inductance of phase A, L As is the stator leakage inductance of phase A, L Ar is the A-phase rotor leakage inductance.

[0079] Based on the same method, the leakage inductance of phase B and the leakage inductance of phase C can be obtained, which will not be described in detail here.

[0080] S33, determining the stator leakage inductance and the rotor leakage inductance of the motor according to the leakage inductance of each phase.

[0081] Specifically, the motor stator leakage inductance and the motor rotor leakage inductance can be calculated by the following formula:

[0082]

[0083] Among them, L s is the stator leakage inductance of the motor, L r is the motor rotor leakage inductance, the two are the same.

[0084] In the above embodiment, by controlling any one phase output of the inverter to be open-circuited, and controlling the remaining two phases of the inverter to apply AC excitation current to the corresponding motor windings, the reactive power and effective current value of at least one of the remaining two phases can be obtained, and the stator leakage inductance and the rotor leakage inductance of the motor can be obtained according to the reactive power and effective current value of any one phase and the current frequency of the AC excitation current. The method is simple, reliable and has high accuracy.

[0085] In some embodiments, Figure 7 As shown, after determining the stator leakage inductance and the rotor leakage inductance of the motor, the method further includes:

[0086] S51, using the VF control mode to drag the motor to a preset frequency, and determine the current reactive power and the current effective current value according to the voltage value of each phase and the current value of each phase, and determine the motor stator inductance and / or the motor rotor inductance according to the current reactive power and the current effective current value.

[0087] Specifically, when the motor is in the no-load state, its slip rate S is close to 0. At this time, the motor equivalent circuit diagram is as follows: Figure 8 As shown. When the motor is in the no-load state, the VF control mode (i.e., the mode that ensures that the output voltage is proportional to the frequency) can be used to drag the motor to the preset frequency. The preset frequency can be 80% to 90% of the rated frequency of the motor. Then, the voltage value and current value of each phase of the motor are obtained, and the reactive power and effective current value of each phase are calculated based on the voltage value and current value of each phase, and the stator inductance and rotor inductance of the motor are calculated based on the reactive power and effective current value of each phase. Among them, the calculation of the reactive power and effective current value of each phase, as well as the stator inductance and rotor inductance of the motor can be calculated by referring to formulas (2)-(5), which will not be described in detail here.

[0088] S52, determining the motor mutual inductance according to the motor stator inductance and / or the motor rotor inductance, and the motor stator leakage inductance and / or the motor rotor leakage inductance.

[0089] Specifically, the difference between the motor stator inductance and the motor stator leakage inductance is the motor mutual inductance, or the difference between the motor rotor inductance and the motor rotor leakage inductance is the motor mutual inductance.

[0090] In the above embodiment, when the motor is in a no-load state, the motor is dragged to a preset frequency by adopting a VF control mode, and the current reactive power and the current effective current value are determined according to the voltage value of each phase and the current value of each phase, and then the motor electronic inductance, electronic rotor inductance and motor mutual inductance are obtained according to the reactive power and the effective current value. The method is simple, reliable and highly accurate.

[0091] In some embodiments, Fig. 9 As shown, after the inverter stops outputting, the motor parameter identification method also includes:

[0092] S61, obtaining each back electromotive force of the motor.

[0093] Specifically, after the inverter stops outputting, the motor will continue to rotate under the action of inertia and generate back EMF (i.e. induced EMF), at which time the voltage of each phase winding of the motor can be obtained to obtain each back EMF. It should be noted that the inverter stops outputting, which can be done after applying a three-phase AC excitation current to the motor. For example, after the motor mutual inductance is identified, the inverter stops outputting, and after half a rotation cycle when the inverter stops outputting, the back EMF of each motor is collected to ensure that the inverter stops outputting completely and the motor speed is not too low, resulting in inaccurate collection of each back EMF of the motor.

[0094] S62, determining a back-EMF modulus value according to each back-EMF of the motor, and determining a rotor time constant according to the back-EMF modulus value.

[0095] Specifically, after obtaining each back EMF of the motor, the back EMF modulus E is calculated based on each back EMF of the motor. mod ,Right now Among them, E A 、E B and E C are the back electromotive force of phase A, phase B and phase C respectively. Then, according to the back electromotive force modulus E mod Calculate the rotor time constant of the motor.

[0096] In some embodiments, determining the rotor time constant based on the back-EMF modulus value includes: obtaining the back-EMF modulus value determined at the first back-EMF sampling moment, and obtaining the back-EMF modulus value determined at the Nth back-EMF sampling moment, wherein the back-EMF modulus value determined at the Nth back-EMF sampling moment is less than the product of the first preset coefficient and the back-EMF modulus value determined at the first back-EMF sampling moment; determining the rotor time constant based on the back-EMF modulus value determined at the first back-EMF sampling moment, the back-EMF modulus value determined at the Nth back-EMF sampling moment, and N back-EMF sampling periods, where N is an integer greater than 1.

[0097] That is to say, N back-EMF modulus values ​​can be obtained, and the rotor time constant can be calculated based on the N back-EMF modulus values. Specifically, the back-EMF modulus value at time t=0 can be obtained first: Among them, E A0 、E B0 and E C0 are the reverse potentials of phase A, phase B and phase C at time t=0 respectively; then, obtain t=N*T s The back EMF modulus at time Among them, E AN 、E BN and E CN They are t=N*T sAt this moment, phase A, phase B, and phase C have opposite potentials, and E modN <K1*E mod0 , K1 is the first preset coefficient, which can be determined according to the actual situation, such as K1 is 0.3-0.5, to ensure that there is a certain difference between the two back-EMF moduli, thereby ensuring the accuracy of the rotor time constant. Then, the rotor time constant is calculated based on the two back-EMF moduli, for example, the rotor time constant is calculated by the following formula:

[0098]

[0099] Among them, T r is the rotor time constant, T s is the back EMF sampling period, E mod0 is the back EMF modulus value determined at the first back EMF sampling moment, E modN It is the back-EMF modulus value determined at the Nth back-EMF sampling moment.

[0100] In the above embodiment, after the frequency converter stops outputting, the rotor time constant can be quickly determined based on the motor back electromotive force, and the method is simple, reliable and highly accurate.

[0101] In some embodiments, after determining the motor mutual inductance, the method further includes: controlling the inverter to stop outputting, and determining the motor rotor resistance according to the motor rotor inductance and the rotor time constant determined after the inverter stops outputting, that is, the motor rotor resistance R r =L r / T r .

[0102] It should be noted that based on Figure 5From the T-type equivalent circuit of the asynchronous motor shown, it can be seen that the motor rotor leakage inductance and the motor rotor resistance are connected in series and then connected in parallel with the motor mutual inductance. When identifying the motor rotor leakage inductance and the motor rotor resistance, a higher frequency AC excitation voltage is required. The related technology usually adopts the high-frequency pulse injection method or the high-frequency sine wave excitation method. However, for medium and high voltage inverters with complex topology structures, high-frequency pulse injection is difficult due to the system hardware configuration. High-frequency sine wave excitation is relatively easy to achieve, but there is a problem: due to the inconsistent winding forms of the stator and rotor windings of the asynchronous motor, the stator of the motor generally uses multiple strands of fine wires in parallel, the operating current frequency is relatively high, and the skin effect is small at high frequency. The rotor bars of the motor are generally made of thick aluminum bars or copper bars welded together, and the rotor current operating frequency is close to the slip frequency. When the high-frequency sine wave excitation current is injected, the skin effect is obvious, resulting in a large error in the identification of the motor rotor resistance. In the embodiments of the present invention, the motor rotor inductance can be identified by inputting AC excitation current into the motor, and after the inverter stops outputting, the rotor time constant can be identified based on the motor back electromotive force, and then the motor rotor resistance can be obtained based on the motor rotor inductance and the rotor time constant. There is no need to adopt high-frequency pulse injection method or high-frequency sinusoidal wave excitation method. The method is simple, reliable and highly accurate.

[0103] In summary, according to the motor parameter identification method of the embodiment of the present invention, the motor stator resistance and the inverter output phase voltage deviation can be identified by applying a DC voltage to the motor; the motor stator leakage inductance and the motor rotor leakage inductance can be identified by applying an AC excitation current of a certain frequency to the motor; the motor stator inductance, the motor rotor inductance, the motor mutual inductance, the rotor time constant and the motor rotor resistance can be identified by applying a three-phase AC excitation current to the motor. In this way, the motor parameters are identified, and the problems of large error influence in complex topology systems and difficulty in identifying rotor resistance are solved. Experiments have proved that the engineering application is simple and reliable, and it is particularly suitable for medium and high voltage complex topology frequency conversion systems.

[0104] In some embodiments, a computer-readable storage medium is further provided, on which a motor parameter identification program is stored. When the motor parameter identification program is executed by a processor, the aforementioned motor parameter identification method is implemented.

[0105] According to the computer-readable storage medium of the embodiment of the present invention, the motor parameter identification method is executed by the processor to realize the identification of the motor parameters, solve the problems of large error influence of complex topology system and high difficulty in rotor resistance identification, and it has been proved by experiments that the engineering application is simple and reliable, especially suitable for medium and high voltage complex topology structure frequency conversion system.

[0106] In some embodiments, an electronic device is also provided.

[0107] refer to Fig.10As shown, the electronic device 100 includes a memory 110, a processor 120, and a motor parameter identification program stored in the memory 110 and executable on the processor 120. When the processor 120 executes the motor parameter identification program, the motor parameter identification method described above is implemented.

[0108] According to the electronic device of the embodiment of the present invention, the processor executes the aforementioned motor parameter identification method to realize the identification of motor parameters, solves the problems of large error influence of complex topology system and great difficulty in rotor resistance identification, and experiments have proved that the engineering application is simple and reliable, and is particularly suitable for medium and high voltage complex topology structure frequency conversion systems.

[0109] In some embodiments, a motor parameter identification device is also provided.

[0110] refer to Fig.11 As shown, the motor parameter identification device 200 includes: an acquisition module 210 and an identification module 220. The acquisition module 210 is used to acquire the voltage value of each phase and the current value of each phase based on the way of applying DC voltage to the motor winding; the identification module 220 is used to determine the stator resistance of each phase according to the voltage value of each phase and the current value of each phase, and determine the stator resistance of the motor according to the stator resistance of each phase, and determine the output voltage deviation of each phase according to the voltage value of each phase, the current value of each phase and the stator resistance of each phase, and determine the output phase voltage deviation of the inverter according to the output voltage deviation of each phase.

[0111] In some embodiments, the acquisition module 210 is also used to obtain each back EMF of the motor after the inverter stops outputting; the identification module 220 is also used to determine the back EMF modulus value according to each back EMF of the motor, and determine the rotor time constant according to the back EMF modulus value.

[0112] In some embodiments, the identification module 220 is specifically used to: obtain the back EMF modulus value determined at the first back EMF sampling moment, and obtain the back EMF modulus value determined at the Nth back EMF sampling moment, wherein the back EMF modulus value determined at the Nth back EMF sampling moment is less than the product of the first preset coefficient and the back EMF modulus value determined at the first back EMF sampling moment; determine the rotor time constant based on the back EMF modulus value determined at the first back EMF sampling moment, the back EMF modulus value determined at the Nth back EMF sampling moment, and N back EMF sampling cycles, wherein N is an integer greater than 1.

[0113] In some embodiments, the identification module 220 is specifically configured to calculate the rotor time constant according to the following formula:

[0114]

[0115] Among them, T r is the rotor time constant, T s is the back EMF sampling period, Emod0 is the back EMF modulus value determined at the first back EMF sampling moment, E modN It is the back-EMF modulus value determined at the Nth back-EMF sampling moment.

[0116] In some embodiments, the acquisition module 210 is specifically used to: control any one phase output of the inverter to be open, and control the remaining two phases of the inverter to apply a DC voltage to the corresponding motor winding, and adjust the output voltage duty cycle of the inverter so that the output current of the inverter reaches the first target current and the second target current respectively; determine the first output voltage duty cycle when the output current of the inverter reaches the first target current, and determine the second output voltage duty cycle when the output current of the inverter reaches the second target current, and determine the first phase voltage value and the second phase voltage value of at least one phase of the remaining two phases according to the first output voltage duty cycle, the second output voltage duty cycle and the bus voltage of the inverter; when the output current of the inverter reaches the first target current and the second target current respectively, obtain the first phase current value and the second phase current value of at least one phase of the remaining two phases.

[0117] In some embodiments, the identification module 220 is specifically used to: determine the voltage difference between the first phase voltage value and the second phase voltage value of any phase, determine the current difference between the first phase current value and the second phase current value of the phase, and determine the stator resistance of the phase based on the voltage difference and the current difference.

[0118] In some embodiments, the output voltage deviation of any phase is calculated according to the following formula:

[0119]

[0120] Among them, ΔU x is the output voltage deviation of any phase, are the first phase voltage value and the second phase voltage value of the phase, I x1 ,I x2 are the first phase current value and the second phase current value of the phase respectively, R sx is the stator resistance of this phase.

[0121] In some embodiments, the identification module 220 is also used to: after determining the output phase voltage deviation of the inverter, control any one phase output of the inverter to be open-circuited, and control the remaining two phases of the inverter to apply AC excitation current to the corresponding motor windings to obtain the reactive power and effective current value of at least one of the remaining two phases; determine the leakage inductance of the phase according to the reactive power and effective current value of any phase and the current frequency of the AC excitation current; determine the stator leakage inductance and the rotor leakage inductance of the motor according to the leakage inductance of each phase.

[0122] In some embodiments, the identification module 220 is also used to: after determining the stator leakage inductance and the rotor leakage inductance of the motor, use the VF control mode to drag the motor to a preset frequency, and determine the current reactive power and the current effective current value according to the voltage value of each phase and the current value of each phase, and determine the motor stator inductance and / or the motor rotor inductance according to the current reactive power and the current effective current value; determine the motor mutual inductance according to the motor stator inductance and / or the motor rotor inductance, and the motor stator leakage inductance and / or the motor rotor leakage inductance.

[0123] In some embodiments, the identification module 220 is further used to: after determining the motor mutual inductance, control the inverter to stop outputting, and determine the motor rotor resistance according to the motor rotor inductance and the rotor time constant determined after the inverter stops outputting.

[0124] It should be noted that, for the description of the motor parameter identification device in this application, please refer to the description of the motor parameter identification method in this application, and the details will not be repeated here.

[0125] According to the motor parameter identification device of the embodiment of the present invention, the motor stator resistance and the inverter output phase voltage deviation can be identified by applying a DC voltage to the motor; the motor stator leakage inductance and the motor rotor leakage inductance can be identified by applying an AC excitation current of a certain frequency to the motor; the motor stator inductance, the motor rotor inductance, the motor mutual inductance, the rotor time constant and the motor rotor resistance can be identified by applying a three-phase AC excitation current to the motor. In this way, the motor parameters are identified, and the problems of large error influence in complex topology systems and difficulty in identifying rotor resistance are solved. Experiments have proved that the engineering application is simple and reliable, and it is particularly suitable for medium and high voltage complex topology frequency conversion systems.

[0126] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0127] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0128] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0129] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for identifying motor parameters, characterized in that: include: Based on the way of applying DC voltage to the motor winding, a voltage value of each phase and a current value of each phase are obtained; Determining the stator resistance of each phase according to the voltage value of each phase and the current value of each phase; Determine the stator resistance of the motor according to the stator resistance of each phase, determine the output voltage deviation of each phase according to the voltage value of each phase, the current value of each phase and the stator resistance of each phase, and determine the output phase voltage deviation of the inverter according to the output voltage deviation of each phase; After the frequency converter stops outputting, the method further includes: Get each back electromotive force of the motor; Determine a back-EMF modulus value according to each back-EMF of the motor, and determine a rotor time constant according to the back-EMF modulus value; The rotor time constant is calculated according to the following formula: Among them, T r is the rotor time constant, T s is the back EMF sampling period, E mod0 is the back EMF modulus value determined at the first back EMF sampling moment, E modN is the back-EMF modulus value determined at the Nth back-EMF sampling moment, where N is an integer greater than 1.

2. The method according to claim 1, characterized in that: Determining a rotor time constant according to the back-EMF modulus value includes: Obtaining a back EMF modulus value determined at a first back EMF sampling moment, and obtaining a back EMF modulus value determined at an Nth back EMF sampling moment, wherein the back EMF modulus value determined at the Nth back EMF sampling moment is less than a product of a first preset coefficient K1 and the back EMF modulus value determined at the first back EMF sampling moment, 0.3≤K1≤0.5; The rotor time constant is determined according to the back-EMF modulus value determined at the first back-EMF sampling moment, the back-EMF modulus value determined at the Nth back-EMF sampling moment, and N back-EMF sampling periods.

3. The method according to any one of claims 1 to 2, characterized in that: Based on the way of applying DC voltage to the motor winding, the voltage value of each phase and the current value of each phase are obtained, including: Controlling any one phase output of the inverter to be open-circuited, and controlling the remaining two phases of the inverter to apply a DC voltage to the corresponding motor winding, and adjusting the output voltage duty cycle of the inverter so that the output current of the inverter reaches a first target current and a second target current respectively; Determine a first output voltage duty cycle when the output current of the inverter reaches the first target current, determine a second output voltage duty cycle when the output current of the inverter reaches the second target current, and determine a first phase voltage value and a second phase voltage value of at least one phase of the remaining two phases according to the first output voltage duty cycle, the second output voltage duty cycle and the bus voltage of the inverter; When the output current of the inverter reaches the first target current and the second target current respectively, a first phase current value and a second phase current value of at least one phase of the remaining two phases are obtained.

4. The method according to claim 3, characterized in that Determining the stator resistance of each phase according to the voltage value of each phase and the current value of each phase includes: Determine the voltage difference between the first phase voltage value and the second phase voltage value of any phase, determine the current difference between the first phase current value and the second phase current value of the phase, and determine the stator resistance of the phase based on the voltage difference and the current difference.

5. The method according to claim 4, characterized in that The output voltage deviation of any phase is calculated according to the following formula: Among them, ΔU x is the output voltage deviation of any phase, are the first phase voltage value and the second phase voltage value of the phase, I x1 ,I x2 are the first phase current value and the second phase current value of the phase respectively, R sx is the stator resistance of this phase.

6. The method according to claim 3, characterized in that After determining the inverter output phase voltage deviation, the method further includes: Controlling any one phase output of the frequency converter to be open-circuited, and controlling the remaining two phases of the frequency converter to apply AC excitation current to the corresponding motor windings, so as to obtain reactive power and current effective value of at least one phase of the remaining two phases; Determine the leakage inductance of any phase according to the reactive power and current effective value of the phase and the current frequency of the AC excitation current; The motor stator leakage inductance and the motor rotor leakage inductance are determined based on the leakage inductance of each phase.

7. The method according to claim 6, characterized in that After determining the stator leakage inductance and the rotor leakage inductance of the motor, the method further includes: The motor is dragged to a preset frequency by adopting the VF control mode, and the current reactive power and the current effective current are determined according to the voltage value of each phase and the current value of each phase, and the stator inductance and / or the rotor inductance of the motor are determined according to the current reactive power and the current effective current; The motor mutual inductance is determined according to the motor stator inductance and / or the motor rotor inductance, and the motor stator leakage inductance and / or the motor rotor leakage inductance.

8. The method according to claim 7, characterized in that After determining the mutual inductance of the motor, the method further includes: The frequency converter is controlled to stop outputting, and the motor rotor resistance is determined according to the motor rotor inductance and a rotor time constant determined after the frequency converter stops outputting.

9. A computer-readable storage medium, characterized in that: A motor parameter identification program is stored thereon, and when the motor parameter identification program is executed by a processor, the motor parameter identification method according to any one of claims 1-8 is implemented.

10. An electronic device, characterized in that: It comprises a memory, a processor and a motor parameter identification program stored in the memory and executable on the processor. When the processor executes the motor parameter identification program, the motor parameter identification method according to any one of claims 1 to 8 is implemented.

11. A motor parameter identification device, characterized in that: The motor parameter identification device is used to implement the motor parameter identification method according to any one of claims 1 to 8, comprising: An acquisition module, which acquires a voltage value of each phase and a current value of each phase based on a method of applying a DC voltage to a motor winding; An identification module is used to determine the stator resistance of each phase according to the voltage value of each phase and the current value of each phase, and determine the stator resistance of the motor according to the stator resistance of each phase, and determine the output voltage deviation of each phase according to the voltage value of each phase, the current value of each phase and the stator resistance of each phase, and determine the output phase voltage deviation of the inverter according to the output voltage deviation of each phase.

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