A parameter identification method, device and equipment of a synchronous motor and a medium

Abstract

This application discloses a method, apparatus, device, and medium for parameter identification of a synchronous motor. The method includes: obtaining the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage by varying the carrier frequency; obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter using a target converter circuit model of the inverter and the synchronous motor and multiple sets of measured values; injecting a low-frequency sinusoidal current into the synchronous motor, and determining the current corresponding to the minimum ratio of the third harmonic amplitude to the fundamental amplitude of the synchronous motor at the given voltage as the bias current identification result of the inverter; when the direct and quadrature axes of the synchronous motor have saturation characteristics, obtaining the maximum peak point of its response current spike under the second harmonic and the zero-crossing point of the fundamental wave, injecting positive and negative voltage pulses into these two points respectively, and determining the type of synchronous motor and the direct and quadrature axis inductance based on the peak value of the response current. This method can improve the accuracy of synchronous motor parameter identification.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering, and in particular to a method, apparatus, equipment, and medium for parameter identification of a synchronous motor. Background Technology

[0002] For synchronous motor model design, the accuracy of the identified parameters directly affects the motor's operating state. Therefore, in practical applications, a parameter identification process is typically performed before operation to obtain the main parameters of the synchronous motor model. These parameters include the stator resistance, direct and quadrature axis inductance, back EMF constant, and rotor mechanical time constant. Furthermore, since the windings and inverter bridge arms together form the commutation circuit during synchronous motor operation, the inverter's nonlinear voltage error characteristics are also considered in the synchronous motor parameter identification process.

[0003] Among the parameters to be identified, the stator resistance, direct-axis inductance, and inverter voltage error of the synchronous motor can be identified when the synchronous motor is stationary. The stator resistance of the synchronous motor is typically identified through multi-segment DC injection or ramp DC injection. However, this method is time-consuming and requires at least two DC injection segments to avoid the influence of inverter nonlinearity on the stator resistance identification result. The inverter voltage error can be identified by injecting multiple DC signals into the synchronous motor. However, this method is easily affected by stator resistance identification errors, thus reducing the accuracy of inverter voltage error identification. The direct-axis inductance of the synchronous motor is typically identified by injecting a pulse sequence or high-frequency signal along the air gap circumference of the synchronous motor. However, this method cannot effectively identify the saturation characteristics of the direct-axis stator inductance and cannot effectively distinguish the direct-axis inductance of some special motors.

[0004] In summary, how to further improve the accuracy of synchronous motor parameter identification results is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method, apparatus, device, and medium for identifying parameters of a synchronous motor, so as to improve the accuracy of the parameter identification results of the synchronous motor. The specific solution is as follows:

[0006] A method for parameter identification of a synchronous motor, comprising:

[0007] When injecting the target DC current into the synchronous motor, the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage are obtained by changing the carrier frequency, and multiple sets of measurement values ​​are obtained.

[0008] The stator resistance of the synchronous motor and the saturation voltage error of the inverter are obtained using the target converter circuit model of the inverter and the synchronous motor, as well as multiple sets of measurement values.

[0009] A low-frequency sinusoidal current is injected into the synchronous motor, and during the injection process, the preset bias current is gradually adjusted according to the identified saturation voltage error and the preset nonlinear voltage error of the inverter to find the target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value, and the target current is determined as the bias current identification result of the inverter.

[0010] Voltage pulses of varying amplitudes from low to high are injected into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor, and to obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero-crossing point of the fundamental wave.

[0011] A set of positive and negative voltage pulses are injected into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value. The type of synchronous motor and the quadrature and direct axis inductance of the synchronous motor are determined based on the first positive and negative current peak value and the second positive and negative current peak value.

[0012] Preferably, the process of obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values ​​includes:

[0013] Under DC conditions, obtain the first commutation circuit model of the inverter and the synchronous motor;

[0014] When the target DC current is injected into the synchronous motor, the first converter circuit model is adjusted using the saturation voltage error of the inverter to obtain the target converter circuit model;

[0015] The stator resistance of the synchronous motor and the saturation voltage error of the inverter are calculated using the target converter circuit model and multiple sets of measurement values.

[0016] Preferably, the amplitude of the low-frequency sinusoidal current is less than 50% of the amplitude of the rated current of the synchronous motor.

[0017] Preferably, the process of injecting voltage pulses of varying amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor includes:

[0018] Using the stator winding axis of the synchronous motor as the coordinate axis, six sets of voltage pulses with the same amplitude are injected into the synchronous motor at positions of 0°, 180°, 120°, 300°, 240°, and 60° along the circumference of the synchronous motor stator. The direct-axis inductance and quadrature-axis inductance of the synchronous motor under the current excitation amplitude are calculated based on the current spikes generated by the six sets of voltage pulses with the same amplitude.

[0019] The amplitude of the voltage pulse injected into the synchronous motor is gradually increased, and the direct-axis inductance and quadrature-axis inductance of the synchronous motor under different excitation amplitudes are calculated based on the current spikes generated by the voltage pulses of different amplitudes, so as to obtain the saturation characteristics of the stator inductance of the synchronous motor.

[0020] Preferably, the process of injecting a set of positive and negative voltage pulses into the maximum peak point and the zero-crossing point respectively to obtain a first positive and negative current peak value and a second positive and negative current peak value, and determining the type of the synchronous motor and the direct and quadrature axis inductance of the synchronous motor based on the first positive and negative current peak value and the second positive and negative current peak value, includes:

[0021] Obtain the target model of the direct and quadrature axis inductances of the synchronous motor;

[0022] A set of positive and negative voltage pulses is injected into the maximum peak point to obtain the first positive current peak value and the first negative current peak value, and a set of positive and negative voltage pulses is injected into the zero crossing point to obtain the second positive current peak value and the second negative current peak value;

[0023] If the difference between the first positive current peak value and the first negative current peak value is greater than or equal to the first preset value, the synchronous motor is determined to be a permanent magnet synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the first positive current peak value, the first negative current peak value and the target model.

[0024] If the difference between the second positive current peak value and the second negative current peak value is greater than or equal to the second preset value, the synchronous motor is determined to be a flux-enhanced permanent magnet synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the second positive current peak value, the second negative current peak value and the target model.

[0025] If the difference between the first positive current peak value and the first negative current peak value is less than the first preset value, and the difference between the second positive current peak value and the second negative current peak value is less than the second preset value, then the synchronous motor is determined to be a synchronous reluctance motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the second positive current peak value, the second negative current peak value and the target model.

[0026] Preferably, the process of obtaining the target model of the direct and quadrature axis inductances of the synchronous motor includes:

[0027] Multiple sets of target voltage pulses with equal amplitude and pulse width are injected into the synchronous motor at different positions along the circumference of the synchronous motor stator, and the target response current of the synchronous motor is obtained.

[0028] The target model of the synchronous motor's AC and DC axis inductance is determined based on the fundamental component and second harmonic of the target response current, as well as the amplitude and pulse width of the target voltage pulse.

[0029] Accordingly, the present invention also discloses a parameter identification device for a synchronous motor, comprising:

[0030] The numerical measurement module is used to obtain the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage by changing the carrier frequency when injecting target DC power into the synchronous motor, and obtain multiple sets of measurement values.

[0031] The parameter acquisition module is used to acquire the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values.

[0032] The current lookup module is used to inject low-frequency sinusoidal current into the synchronous motor, and during the injection process, it gradually adjusts the preset bias current according to the identified saturation voltage error and the preset nonlinear voltage error to compensate the inverter, so as to find the target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value, and determines the target current as the bias current identification result of the inverter.

[0033] The characteristic excitation module is used to inject voltage pulses of different amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor, and to obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero crossing point of the fundamental wave.

[0034] The inductance identification module is used to inject a set of positive and negative voltage pulses into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value, and to determine the type of the synchronous motor and the quadrature and direct axis inductance of the synchronous motor based on the first positive and negative current peak value and the second positive and negative current peak value.

[0035] Accordingly, the present invention also discloses a parameter identification device for a synchronous motor, comprising:

[0036] Memory, used to store computer programs;

[0037] A processor is configured to execute the computer program to implement the steps of a parameter identification method for a synchronous motor as disclosed above.

[0038] Accordingly, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a parameter identification method for a synchronous motor as disclosed above.

[0039] As can be seen, in this invention, the identification of the stator resistance of the synchronous motor and the saturation voltage error of the inverter is achieved by injecting a DC current with a varying carrier frequency into the synchronous motor. This relatively reduces the time required for identifying the stator resistance of the synchronous motor. Furthermore, by injecting a low-frequency sinusoidal current into the synchronous motor to determine the inverter's bias current identification result, the influence of the synchronous motor stator resistance on the inverter identification result can be avoided, thereby improving the accuracy of inverter parameter identification. Simultaneously, for special types of synchronous motors, the quadrature-axis and direct-axis inductances of the synchronous motor are determined by injecting positive and negative voltage pulses at specific locations within the synchronous motor, thereby avoiding misjudgments in the quadrature-axis and direct-axis inductance identification results. Therefore, the method provided by this invention can significantly improve the accuracy of synchronous motor parameter identification results. Correspondingly, the synchronous motor parameter identification device, equipment, and medium provided by this invention also have the above-mentioned beneficial effects. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 A flowchart illustrating a parameter identification method for a synchronous motor provided in an embodiment of the present invention;

[0042] Figure 2 This is a voltage error curve diagram of the inverter;

[0043] Figure 3 A schematic diagram illustrating the process of identifying the inverter's bias current in order to inject low-frequency sinusoidal current into a synchronous motor.

[0044] Figure 4 A schematic diagram showing how to inject positive and negative voltage pulses into the synchronous motor response current spike at the maximum peak point under the second harmonic and the zero-crossing point of the fundamental wave, respectively, and to determine the direct and quadrature axis inductance of the synchronous motor.

[0045] Figure 5The linear fitting curve of the quadrature axis inductance of the permanent magnet synchronous motor is given when the synchronous motor is a permanent magnet synchronous motor.

[0046] Figure 6 The linear fitting curve of the direct-axis inductance of the permanent magnet synchronous motor is given when the synchronous motor is a permanent magnet synchronous motor.

[0047] Figure 7 This is the linear fitting curve of the quadrature axis inductance of the synchronous reluctance motor when the synchronous motor is a synchronous reluctance motor;

[0048] Figure 8 This is the linear fitting curve of the direct-axis inductance of the synchronous reluctance motor when the synchronous motor is a synchronous reluctance motor;

[0049] Figure 9 This is a structural diagram of a parameter identification device for a synchronous motor provided in an embodiment of the present invention;

[0050] Figure 10 This is a structural diagram of a parameter identification device for a synchronous motor provided in an embodiment of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Please see Figure 1 , Figure 1 A flowchart of a parameter identification method for a synchronous motor provided in an embodiment of the present invention is shown. The method includes:

[0053] Step S11: When injecting the target DC current into the synchronous motor, the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage are obtained by changing the carrier frequency, and multiple sets of measurement values ​​are obtained.

[0054] Step S12: Use the target converter circuit model of the inverter and synchronous motor and multiple sets of measurement values ​​to obtain the stator resistance of the synchronous motor and the saturation voltage error of the inverter.

[0055] Step S13: Inject low-frequency sinusoidal current into the synchronous motor, and gradually adjust the preset bias current according to the identified saturation voltage error and the preset nonlinear voltage error of the compensation inverter during the injection process, so as to find the target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value, and determine the target current as the bias current identification result of the inverter.

[0056] Step S14: Inject voltage pulses of different amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the synchronous motor stator inductance, and obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero crossing point of the fundamental wave.

[0057] Step S15: Inject a set of positive and negative voltage pulses into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value, and determine the type of synchronous motor and the quadrature and direct axis inductance of the synchronous motor based on the first positive and negative current peak value and the second positive and negative current peak value.

[0058] In this embodiment, a parameter identification method for a synchronous motor is provided. Using this method to identify the parameters of a synchronous motor can significantly improve the accuracy of parameter identification.

[0059] Specifically, when identifying the stator resistance of the synchronous motor and the saturation voltage error of the inverter, the first step is to obtain a commutation circuit model composed of the inverter and the synchronous motor under DC conditions. According to the commutation process during the dead zone of the inverter, when a sufficiently large DC current is injected into the synchronous motor, the commutation voltage error of the inverter will approach the saturation voltage error of the inverter. Under this condition, the saturation voltage error of the inverter will be a function that is positively correlated with the carrier period.

[0060] Based on the above theory, in this embodiment, to obtain the stator resistance of the synchronous motor and the saturation voltage error of the inverter, the first step is to convert the converter circuit model of the inverter and synchronous motor in DC state into a target converter circuit model corresponding to when the inverter's converter voltage error approaches the inverter's saturation voltage error. When the target converter circuit model of the inverter and synchronous motor is obtained, where the inverter's converter voltage error approaches the inverter's saturation voltage error, a target DC current is injected into the synchronous motor. The steady-state value of the synchronous motor under a given voltage and the measured bus voltage are obtained by varying the carrier frequency, resulting in multiple sets of measured values. Then, the target converter circuit model of the inverter and synchronous motor and the obtained multiple sets of measured values ​​are used to fit and obtain the stator resistance of the synchronous motor and the inverter's saturation voltage error. Specifically, in actual operation, the target DC current can be set to a value greater than 30% of the inverter's rated current.

[0061] Compared to existing technologies, this method identifies the stator resistance of the synchronous motor and the saturation voltage error of the inverter by injecting a DC current with a varying carrier frequency into the synchronous motor. Therefore, this method can relatively reduce the time required for identifying the stator resistance of the synchronous motor.

[0062] Please see Figure 2 , Figure 2 This is a voltage error curve diagram of the inverter. (Through...) Figure 2 It can be seen that when the inverter's saturation voltage error is identified, the inverter voltage error can be approximately completely compensated by properly adjusting the inverter current. In this case, by injecting a sinusoidal current into the synchronous motor, the given voltage of the synchronous motor will also become a distortion-free sinusoidal wave.

[0063] In this embodiment, to avoid distortion caused by the synchronous motor's inductance saturation characteristics when applying a given voltage, a low-frequency sinusoidal current is injected into the synchronous motor, and the amplitude of the low-frequency sinusoidal current is limited to less than 50% of the synchronous motor's rated current. When injecting the low-frequency sinusoidal current into the synchronous motor, the preset bias current is gradually adjusted based on the identified saturation voltage error and the preset nonlinear voltage error of the inverter to find the target current corresponding to the minimum ratio of the third harmonic amplitude to the fundamental frequency amplitude under the given voltage. When the target current corresponding to the minimum ratio of the third harmonic amplitude to the fundamental frequency amplitude under the given voltage is found, the target current is determined as the inverter's bias current identification result.

[0064] It is understandable that the inverter bias current is determined by injecting a low-frequency sinusoidal current into the synchronous motor during the identification process. The entire process is not coupled with the stator resistance of the synchronous motor. Therefore, this method can improve the identification accuracy in the process of identifying the inverter bias current.

[0065] Because existing technologies cannot identify the saturation characteristics of the direct and quadrature axis stator inductance of a synchronous motor, nor can they accurately distinguish some special types of synchronous motors, misalignment in the identification results of the direct and quadrature axis inductance of the synchronous motor often occurs. Therefore, in this embodiment, to avoid the above situation, firstly, voltage pulses of different amplitudes from low to high are injected into the synchronous motor to excite the saturation characteristics of the direct and quadrature axis stator inductance of the synchronous motor. Under the state where the direct and quadrature axis inductance of the synchronous motor has saturation characteristics, the maximum peak point of the corresponding current spike of the synchronous motor under the second harmonic and the zero-crossing point of the fundamental wave are obtained. Then, a set of positive and negative voltage pulses are injected into the maximum peak point of the response current spike of the synchronous motor under the second harmonic and the zero-crossing point of the fundamental wave, respectively, to determine the magnitude relationship of the direct and quadrature axis inductance of the synchronous motor. That is, when a set of positive and negative voltage pulses are injected into the synchronous motor response current spike at the maximum peak point of the second harmonic and the zero crossing point of the fundamental wave, respectively, and the first positive and negative current spike and the second positive and negative current spike value generated by the two voltage pulses are obtained, the type of synchronous motor and the quadrature-direct axis inductance of the synchronous motor can be accurately determined based on the first positive and negative current spike value and the second positive and negative current spike value.

[0066] As can be seen, in this embodiment, the identification of the synchronous motor stator resistance and inverter saturation voltage error is achieved by injecting a DC current with a varying carrier frequency into the synchronous motor. This relatively reduces the time required for identifying the synchronous motor stator resistance. Furthermore, by injecting a low-frequency sinusoidal current into the synchronous motor to determine the inverter bias current identification result, the influence of the synchronous motor stator resistance on the inverter identification result can be avoided, thereby improving the accuracy of inverter parameter identification. Simultaneously, for special types of synchronous motors, the quadrature-axis and direct-axis inductances of the synchronous motor are determined by injecting positive and negative voltage pulses at specific locations within the synchronous motor, thus avoiding misjudgments in the quadrature-axis and direct-axis inductance identification results. Therefore, the method provided in this embodiment can significantly improve the accuracy of synchronous motor parameter identification results.

[0067] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. As a preferred implementation, the above steps: obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values, include:

[0068] Under DC conditions, obtain the first commutation circuit model of the inverter and synchronous motor;

[0069] When the target DC current is injected into the synchronous motor, the first converter circuit model is adjusted using the saturation voltage error of the inverter to obtain the target converter circuit model.

[0070] The stator resistance of the synchronous motor and the saturation voltage error of the inverter are calculated using the target converter circuit model and multiple sets of measurement values.

[0071] When obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter, the first step is to obtain the first commutation circuit model of the inverter and the synchronous motor under DC conditions. The mathematical expression of the first commutation circuit model of the inverter and the synchronous motor is as follows:

[0072] u * =R s i+u err (i,I off U max (1)

[0073] In the formula, u * R is the given voltage when DC current is injected into a synchronous motor. s u is the sum of the stator resistance and the on-resistance of the switching devices. err (i,I off U max ) represents the nonlinear voltage error of the inverter.

[0074] Analysis of the commutation process during the inverter dead zone reveals that when a sufficiently large DC current is injected into the synchronous motor, the nonlinear voltage error of the inverter during the commutation process approaches a saturation value. This saturation value is positively correlated with the carrier period, or negatively correlated with the carrier frequency.

[0075]

[0076] In the formula, u dc The measured value of the DC bus voltage, t d For corresponding to U max Effective dead time, T c For the carrier period, f c For carrier frequency.

[0077] Substituting equation (2) into equation (1) yields the target converter loop model:

[0078] u * (I inj ) = R s I inj +U max (f c (3)

[0079] In formula (3), I inj is considered a known constant, u * and f c Treating R as a variable s and U max If these are considered as parameters, then the stator resistance of the synchronous motor and the saturation voltage error of the inverter can be effectively identified by using two or more sets of DC currents with different carrier frequencies.

[0080] In this embodiment, to achieve the above objective, a constant DC current I is injected into the synchronous motor through closed-loop current regulation. inj , among which, I inj The amplitude is greater than 50% of the inverter's rated current. During the injection of DC current into the synchronous motor, carrier frequencies of 2kHz, 4kHz, and 8kHz were used sequentially, and the steady-state values ​​of the synchronous motor under a given voltage and the measured values ​​of the bus voltage were obtained, resulting in the following three sets of measurement data: in, and The steady-state values ​​of the synchronous motor at a given voltage are u at carrier frequencies of 2kHz, 4kHz, and 8kHz, respectively. dc1 u dc2 and u dc3 The measured values ​​of bus voltage at carrier frequencies of 2kHz, 4kHz, and 8kHz are respectively.

[0081] Substituting the above three sets of measurements into the target converter circuit model, and using least-squares fitting, we can obtain the stator resistance of the synchronous motor and the saturation voltage error of the inverter, that is:

[0082]

[0083] In the formula, R s U is the stator resistance of the synchronous motor. max This refers to the saturation voltage error of the inverter.

[0084] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. As a preferred implementation, the amplitude of the low-frequency sinusoidal current is less than 50% of the rated current amplitude of the synchronous motor.

[0085] In this embodiment, to avoid voltage distortion caused by the inductance saturation characteristics of the synchronous motor, the amplitude of the injected low-frequency sinusoidal current is limited to less than 50% of the motor's rated current when injecting low-frequency sinusoidal current into the synchronous motor. Furthermore, when injecting low-frequency sinusoidal current into the synchronous motor, the inverter's nonlinear voltage compensation is performed using the saturation voltage error identified by variable carrier frequency injection and a preset bias current, with the inverter's initial current set to 0‰I. n and with 10‰I n The search step size gradually increases the preset bias current value. When the ratio of the third harmonic amplitude to the fundamental amplitude of the synchronous motor at a given voltage reaches its minimum, the preset bias current value (target current) at this point is used as the bias current identification result for the inverter. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 A schematic diagram illustrating the process of identifying the inverter's bias current in order to inject low-frequency sinusoidal current into a synchronous motor.

[0086] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. As a preferred implementation method, the above step of obtaining the target model of the direct and quadrature axis inductance of the synchronous motor includes:

[0087] Multiple sets of target voltage pulses with equal amplitude and pulse width are injected into the synchronous motor at different positions along the circumference of the synchronous motor stator, and the target response current of the synchronous motor is obtained.

[0088] The target model of the synchronous motor's AC and DC axis inductance is determined based on the fundamental component and second harmonic of the target response current, as well as the amplitude and pulse width of the target voltage pulse.

[0089] To obtain the target model of the direct-axis inductance of a synchronous motor, the first step is to inject multiple sets of target voltage pulses with equal amplitude and pulse width into the synchronous motor at different positions along the circumference of the stator, and then obtain the target response current of the synchronous motor. Next, Fourier analysis is performed on the target response current, and the fundamental component and second harmonic are extracted to obtain the target model of the direct-axis inductance of the synchronous motor. The expression for the target model of the direct-axis inductance of the synchronous motor is as follows:

[0090]

[0091] In the formula, L d and L q These are the quadrature-axis inductance and direct-axis inductance of a synchronous motor, respectively, V p and T p I1 and I2 are the amplitude and pulse width of the target voltage pulse, respectively. I0 is the fundamental component of the target response current, and I2 is the second harmonic of the target response current.

[0092] It is understandable that this method cannot identify the saturation characteristics of the stator inductance. Furthermore, for some motors with anti-salient pole characteristics, using the above method to identify the direct and quadrature axis inductances of the synchronous motor will result in misaligned identification results.

[0093] In this embodiment, to avoid the above situation, the saturation characteristics of the synchronous motor are identified by changing the amplitude of the voltage pulse injected into the synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined by injecting positive and negative pulses at the second spatial harmonic peak point of the current peak.

[0094] In a preferred embodiment, the above step of injecting voltage pulses of varying amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the synchronous motor stator inductance includes:

[0095] Using the stator winding axis of the synchronous motor as the coordinate axis, six sets of voltage pulses with the same amplitude are injected into the synchronous motor at positions of 0°, 180°, 120°, 300°, 240° and 60° along the circumference of the synchronous motor stator. The direct-axis inductance and quadrature-axis inductance of the synchronous motor under the current excitation amplitude are calculated based on the current spikes generated by the six sets of voltage pulses with the same amplitude.

[0096] The amplitude of the voltage pulse injected into the synchronous motor is gradually increased, and the direct-axis inductance and quadrature-axis inductance of the synchronous motor under different excitation amplitudes are calculated based on the current spikes generated by the voltage pulses of different amplitudes, so as to obtain the saturation characteristics of the stator inductance of the synchronous motor.

[0097] In this embodiment, to identify the saturation characteristics of the direct and quadrature axis inductances of a synchronous motor, firstly, using the stator winding axis of the synchronous motor as the coordinate axis, six sets of voltage pulses with the same amplitude are injected into the synchronous motor at positions of 0°, 180°, 120°, 300°, 240°, and 60° along the circumference of the synchronous motor stator. The direct-axis inductance and quadrature-axis inductance of the synchronous motor under the current excitation amplitude are calculated based on the current spikes generated by the six sets of voltage pulses with the same amplitude. Then, the amplitude of the voltage pulses injected into the synchronous motor is gradually increased, and the direct-axis inductance and quadrature-axis inductance generated by the synchronous motor under different excitations are observed. Finally, the direct-axis inductance and quadrature-axis inductance of the synchronous motor under different excitation amplitudes are calculated based on the current spikes generated by the voltage pulses with different amplitudes to obtain the saturation characteristics of the synchronous motor stator inductance.

[0098] Specifically, a low-amplitude voltage pulse can be injected sequentially into the synchronous motor at positions of 0°, 180°, 120°, 300°, 240°, and 60° along the circumference of the synchronous motor stator. Then, the direct-axis inductance and quadrature-axis inductance of the synchronous motor under the current excitation amplitude are calculated based on the current spike generated by the voltage pulse. After that, the amplitude of the voltage pulse injected into the synchronous motor is gradually increased (the increment step can be selected as 1%), and the above excitation and measurement processes are repeated. When the maximum value of the 6 sets of injected voltage pulses reaches the preset maximum current, the increase of the voltage pulse amplitude and pulse injection are stopped, and the saturation characteristics of the stator inductance of the synchronous motor under different excitation magnitudes are obtained in this way.

[0099] In a preferred embodiment, the above steps—injecting a set of positive and negative voltage pulses into the maximum peak point and the zero-crossing point respectively to obtain the first positive and negative current peak values ​​and the second positive and negative current peak values, and determining the type of synchronous motor and the direct and quadrature axis inductance of the synchronous motor based on the first positive and negative current peak values ​​and the second positive and negative current peak values—include:

[0100] Obtain the target model of the direct and quadrature axis inductances of the synchronous motor;

[0101] A set of positive and negative voltage pulses is injected into the maximum peak point to obtain the first positive current peak value and the first negative current peak value, and a set of positive and negative voltage pulses is injected into the zero-crossing point to obtain the second positive current peak value and the second negative current peak value;

[0102] If the difference between the first positive current peak value and the first negative current peak value is greater than or equal to the first preset value, the synchronous motor is determined to be a permanent magnet synchronous motor, and the quadrature and direct axis inductance of the synchronous motor is determined according to the first positive current peak value, the first negative current peak value and the target model.

[0103] If the difference between the second positive current peak value and the second negative current peak value is greater than or equal to the second preset value, the synchronous motor is determined to be a flux-enhanced permanent magnet synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined based on the second positive current peak value, the second negative current peak value and the target model.

[0104] If the difference between the first positive current peak value and the first negative current peak value is less than the first preset value, and the difference between the second positive current peak value and the second negative current peak value is less than the second preset value, then the synchronous motor is determined to be a synchronous reluctance motor, and the quadrature-direct axis inductance of the synchronous motor is determined based on the second positive current peak value, the second negative current peak value and the target model.

[0105] Based on the excitation of the saturation characteristics of the direct and quadrature axis inductance of the synchronous motor, the maximum peak point of the synchronous motor response current spike under the second harmonic (estimated magnetic pole axis) θ is obtained. max And the zero-crossing point of the fundamental wave (estimated interelectrode axis) θ0, and then towards the maximum peak point θ. max The same voltage pulse V is injected in both directions. pos (θ max ) and V neg (θ max And obtain the current peak value generated by these two voltage pulses, that is, the first positive current peak value I. pos (θ max ) and the first negative current peak value I neg (θ max Then, inject the same voltage pulse V in the opposite directions of the zero-crossing point θ0 of the fundamental wave. pos (θ0) and V neg (θ0), and obtain the current peak value generated by these two voltage pulses, that is, the second positive current peak value I. pos (θ0) and the second negative current peak value I neg (θ0). Please see Figure 4 , Figure 4 A schematic diagram showing how to inject positive and negative voltage pulses into the synchronous motor response current spike at the maximum peak point under the second harmonic and the zero-crossing point of the fundamental wave, respectively, and how to determine the direct and quadrature axis inductance of the synchronous motor.

[0106] If the first positive current peak value I pos (θ max ) and the first negative current peak value I neg (θ max If the difference between the first positive current peak value and the second positive current peak value is greater than or equal to the first preset value, it indicates that the synchronous motor is a permanent magnet synchronous motor. At this time, the first positive current peak value I can be used to determine the synchronous motor. pos (θ max First negative current peak value I neg (θ maxThe quadrature and direct axis inductances of the synchronous motor are determined using the target model.

[0107] Please see Figure 5 and Figure 6 , Figure 5 The linear fitting curve of the quadrature axis inductance of the permanent magnet synchronous motor is given when the synchronous motor is a permanent magnet synchronous motor. Figure 6 This is the linear fitting curve for the direct-axis inductance of a permanent magnet synchronous motor (PMSM). Specifically, when the synchronous motor is a PMSM, the fitting expression for the direct-axis and quadrature-axis inductances of the PMSM is:

[0108]

[0109] If the second positive current peak value I pos (θ0) and the second negative current peak value I neg If the difference between (θ0) and the second preset value is greater than or equal to the second preset value, the synchronous motor is determined to be a flux-enhanced permanent magnet synchronous motor, and the second positive current peak value I is used as the basis for the determination. pos (θ0), the second negative current peak value I neg (θ0) and the target model determine the quadrature and direct-axis inductances of the synchronous motor. It should be noted that when the synchronous motor is a flux-enhanced permanent magnet synchronous motor, its linear fitting curve for the quadrature and direct-axis inductance is similar to... Figure 6 and Figure 7 The linear fitting curves shown are the same, so they will not be described in detail here.

[0110] If the first positive current peak value I pos (θ max ) and the first negative current peak value I neg (θ max The difference between the two values ​​is less than the first preset value, and the second positive current peak value I pos (θ0) and the second negative current peak value I neg If the difference between (θ0) and the second preset value is less than the second preset value, it indicates that the synchronous motor is a synchronous reluctance motor. In this case, the second positive current peak value I can be used as a reference. pos (θ0), the second negative current peak value I neg (θ0) and the target model determine the quadrature and direct axis inductances of the synchronous motor.

[0111] Please see Figure 7 and Figure 8 , Figure 7 This is the linear fitting curve of the quadrature-axis inductance of a synchronous reluctance motor when the synchronous motor is a synchronous reluctance motor. Figure 8 This is the linear fitting curve for the direct-axis inductance of a synchronous reluctance motor when the synchronous motor is a synchronous reluctance motor. Specifically, the fitting expression for the direct-axis and quadrature-axis inductances of the synchronous motor when the synchronous motor is a synchronous reluctance motor is:

[0112]

[0113] Please see Figure 9 , Figure 9 This is a structural diagram of a parameter identification device for a synchronous motor provided in an embodiment of the present invention. The device includes:

[0114] The numerical measurement module 21 is used to obtain the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage by changing the carrier frequency when injecting the target DC current into the synchronous motor, and obtain multiple sets of measurement values.

[0115] The parameter acquisition module 22 is used to obtain the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values.

[0116] The current lookup module 23 is used to inject low-frequency sinusoidal current into the synchronous motor. During the injection process, the preset bias current is gradually adjusted according to the identified saturation voltage error and the preset nonlinear voltage error of the compensation inverter. The target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value is found, and the target current is determined as the bias current identification result of the inverter.

[0117] The characteristic excitation module 24 is used to inject voltage pulses of different amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the synchronous motor stator inductance, and to obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero crossing point of the fundamental wave.

[0118] The inductor identification module 25 is used to inject a set of positive and negative voltage pulses into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value, and to determine the type of synchronous motor and the quadrature and direct axis inductance of the synchronous motor based on the first positive and negative current peak value and the second positive and negative current peak value.

[0119] The parameter identification device for a synchronous motor provided in this embodiment of the invention has the beneficial effects of the parameter identification method for a synchronous motor disclosed above.

[0120] Please see Figure 10 , Figure 10 This is a structural diagram of a parameter identification device for a synchronous motor provided in an embodiment of the present invention. The device includes:

[0121] Memory 31 is used to store computer programs;

[0122] The processor 32 is used to execute a computer program to implement the steps of a parameter identification method for a synchronous motor as disclosed above.

[0123] The parameter identification device for a synchronous motor provided in this embodiment of the invention has the beneficial effects of the parameter identification method for a synchronous motor disclosed above.

[0124] Accordingly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a parameter identification method for a synchronous motor as disclosed above.

[0125] The computer-readable storage medium provided in this embodiment of the invention has the beneficial effects of the aforementioned method for parameter identification of a synchronous motor.

[0126] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0127] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0128] The present invention provides a detailed description of a method, apparatus, device, and medium for parameter identification of a synchronous motor. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for parameter identification of a synchronous motor, characterized in that, include: When injecting the target DC current into the synchronous motor, the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage are obtained by changing the carrier frequency, and multiple sets of measurement values ​​are obtained. The stator resistance of the synchronous motor and the saturation voltage error of the inverter are obtained using the target converter circuit model of the inverter and the synchronous motor, as well as multiple sets of measurement values. A low-frequency sinusoidal current is injected into the synchronous motor, and during the injection process, the preset bias current is gradually adjusted according to the identified saturation voltage error and the preset nonlinear voltage error of the inverter to find the target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value, and the target current is determined as the bias current identification result of the inverter. Voltage pulses of varying amplitudes from low to high are injected into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor, and to obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero-crossing point of the fundamental wave. A set of positive and negative voltage pulses are injected into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value. The type of synchronous motor and the quadrature and direct axis inductance of the synchronous motor are determined based on the first positive and negative current peak value and the second positive and negative current peak value. The process of obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values ​​includes: Under DC conditions, obtain the first commutation circuit model of the inverter and the synchronous motor; When the target DC current is injected into the synchronous motor, the first converter circuit model is adjusted using the saturation voltage error of the inverter to obtain the target converter circuit model; The stator resistance of the synchronous motor and the saturation voltage error of the inverter are calculated using the target converter circuit model and multiple sets of measurement values.

2. The parameter identification method according to claim 1, characterized in that, The amplitude of the low-frequency sinusoidal current is less than 50% of the amplitude of the rated current of the synchronous motor.

3. The parameter identification method according to any one of claims 1 or 2, characterized in that, The process of injecting voltage pulses of varying amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor includes: Using the stator winding axis of the synchronous motor as the coordinate axis, six sets of voltage pulses with the same amplitude are injected into the synchronous motor at positions of 0°, 180°, 120°, 300°, 240°, and 60° along the circumference of the synchronous motor stator. The direct-axis inductance and quadrature-axis inductance of the synchronous motor under the current excitation amplitude are calculated based on the current spikes generated by the six sets of voltage pulses with the same amplitude. The amplitude of the voltage pulse injected into the synchronous motor is gradually increased, and the direct-axis inductance and quadrature-axis inductance of the synchronous motor under different excitation amplitudes are calculated based on the current spikes generated by the voltage pulses of different amplitudes, so as to obtain the saturation characteristics of the stator inductance of the synchronous motor.

4. The parameter identification method according to claim 3, characterized in that, The process of injecting a set of positive and negative voltage pulses into the maximum peak point and the zero-crossing point respectively to obtain the first positive and negative current peak values ​​and the second positive and negative current peak values, and determining the type of the synchronous motor and the direct and quadrature axis inductance of the synchronous motor based on the first positive and negative current peak values ​​and the second positive and negative current peak values, includes: Obtain the target model of the direct and quadrature axis inductances of the synchronous motor; A set of positive and negative voltage pulses is injected into the maximum peak point to obtain the first positive current peak value and the first negative current peak value, and a set of positive and negative voltage pulses is injected into the zero crossing point to obtain the second positive current peak value and the second negative current peak value; If the difference between the first positive current peak value and the first negative current peak value is greater than or equal to the first preset value, the synchronous motor is determined to be a permanent magnet synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the first positive current peak value, the first negative current peak value and the target model. If the difference between the second positive current peak value and the second negative current peak value is greater than or equal to the second preset value, the synchronous motor is determined to be a flux-enhanced permanent magnet synchronous motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the second positive current peak value, the second negative current peak value and the target model. If the difference between the first positive current peak value and the first negative current peak value is less than the first preset value, and the difference between the second positive current peak value and the second negative current peak value is less than the second preset value, then the synchronous motor is determined to be a synchronous reluctance motor, and the quadrature-direct axis inductance of the synchronous motor is determined according to the second positive current peak value, the second negative current peak value and the target model.

5. The parameter identification method according to claim 4, characterized in that, The process of obtaining the target model of the synchronous motor's direct and quadrature axis inductances includes: Multiple sets of target voltage pulses with equal amplitude and pulse width are injected into the synchronous motor at different positions along the circumference of the synchronous motor stator, and the target response current of the synchronous motor is obtained. The target model of the synchronous motor's AC and DC axis inductance is determined based on the fundamental component and second harmonic of the target response current, as well as the amplitude and pulse width of the target voltage pulse.

6. A parameter identification device for a synchronous motor, characterized in that, include: The numerical measurement module is used to obtain the steady-state value of the synchronous motor under a given voltage and the measured value of the bus voltage by changing the carrier frequency when injecting target DC power into the synchronous motor, and obtain multiple sets of measurement values. The parameter acquisition module is used to acquire the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values. The current lookup module is used to inject low-frequency sinusoidal current into the synchronous motor, and during the injection process, it gradually adjusts the preset bias current according to the identified saturation voltage error and the preset nonlinear voltage error to compensate the inverter, so as to find the target current corresponding to the synchronous motor when the ratio of the third harmonic to the fundamental frequency amplitude of the given voltage reaches the minimum value, and determines the target current as the bias current identification result of the inverter. The characteristic excitation module is used to inject voltage pulses of different amplitudes from low to high into the synchronous motor to excite the saturation characteristics of the stator inductance of the synchronous motor, and to obtain the maximum peak point of the synchronous motor response current spike under the second harmonic and the zero crossing point of the fundamental wave. An inductor identification module is used to inject a set of positive and negative voltage pulses into the maximum peak point and the zero crossing point respectively to obtain the first positive and negative current peak value and the second positive and negative current peak value, and to determine the type of the synchronous motor and the quadrature and direct axis inductance of the synchronous motor based on the first positive and negative current peak value and the second positive and negative current peak value. The process of obtaining the stator resistance of the synchronous motor and the saturation voltage error of the inverter using the target converter circuit model of the inverter and the synchronous motor and multiple sets of measurement values ​​includes: Under DC conditions, obtain the first commutation circuit model of the inverter and the synchronous motor; When the target DC current is injected into the synchronous motor, the first converter circuit model is adjusted using the saturation voltage error of the inverter to obtain the target converter circuit model; The stator resistance of the synchronous motor and the saturation voltage error of the inverter are calculated using the target converter circuit model and multiple sets of measurement values.

7. A parameter identification device for a synchronous motor, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the parameter identification method for a synchronous motor as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a parameter identification method for a synchronous motor as described in any one of claims 1 to 5.

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