Permanent magnet synchronous motor parameter on-line identification method and system

Abstract

The invention discloses an online identification method and system for parameters of a permanent magnet synchronous motor, and the method comprises the steps: obtaining related variables of the permanent magnet synchronous motor under the action of a plurality of voltage vectors, and building a mathematical relation among the related variables, the parameters of the permanent magnet synchronous motor and an electrical angle; calculating a stator resistance initial value, an inductance value, a plurality of parameter matrix values and an electrical angle sine and cosine absolute value based on the mathematical relationship and coordinate transformation; based on the mathematical relationship, the stator resistance initial value and a plurality of parameter matrixes, determining the polarity of the sine and cosine values of the electrical angle; calculating electrical angle sine and cosine accurate values according to the electrical angle sine and cosine absolute values and the polarity; and finally, calculating a resistance final value and a flux linkage final value based on the mathematical relationship under the zero voltage vector, the sine and cosine accurate values and a plurality of parameter matrixes. The system can execute the online identification method. Through the arrangement, the identification accuracy of all electrical parameters of the permanent magnet synchronous motor can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of permanent magnet synchronous motor control, and in particular to a method and system for online identification of permanent magnet synchronous motor parameters. Background Art

[0002] Permanent magnet synchronous motors are applied in various fields such as new energy vehicles and aerospace due to their high power density, high reliability, and good dynamic performance. If high-performance control algorithms for permanent magnet synchronous motors are to be realized, accurate permanent magnet synchronous motor parameters need to be obtained. However, the parameters of permanent magnet synchronous motors are easily affected by factors such as temperature and electromagnetic saturation, and thus have strong time-variability. Currently, online parameter identification methods are generally used to identify the parameters of permanent magnet synchronous motors in real time, and the online parameter identification methods generally construct a mathematical model through the voltage equation of the permanent magnet synchronous motor. However, the electrical angle error in the mathematical model will reduce the parameter identification accuracy.

[0003] The electrical angle error is an important factor affecting the online identification accuracy of permanent magnet synchronous motor parameters. In the existing process of online parameter identification of permanent magnet synchronous motors, the electrical angle of the permanent magnet synchronous motor is generally obtained through a Hall position sensor to determine the position information of the permanent magnet synchronous motor. However, due to reasons such as the installation error of the Hall position sensor and the sensor accuracy, the obtained electrical angle has an error, resulting in the accuracy of the online parameter identification result of the permanent magnet synchronous motor being affected, and the existing technology cannot solve this problem.

[0004] Secondly, there are only two inherent motor equations. If the parameters of three or more permanent magnet synchronous motors are to be identified, the problem of underdetermined rank is inevitable. Existing methods for solving the underdetermined rank problem include the injection of excitation signals method and the reduction of identification parameters method. The injection of excitation signals method is to inject high-frequency alternating current signals or low-frequency square wave pulses and other signals, so that a sufficient number of voltage equations can be constructed to meet the rank required for the identification of all permanent magnet synchronous motor parameters. However, if excitation signals are injected, non-negligible torque and speed ripples will be generated, which will deteriorate the operating performance of the permanent magnet synchronous motor.

[0005] In addition, the reduction of identification parameters method includes fixing some permanent magnet synchronous motor parameters as nominal values, two-step group identification, and flux-linkage-free models, etc. The nominal value method and the group identification method are both affected by the accuracy of the initial motor parameters during the online parameter identification of permanent magnet synchronous motors, thus affecting the accuracy of the permanent magnet synchronous motor parameter identification results; the flux-linkage-free model can only achieve the online identification of parameters other than the flux linkage.

[0006] Therefore, how to accurately identify all electrical parameters of permanent magnet synchronous motors without position information, externally applied excitation signals, and initial motor parameters is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In order to solve the deficiencies of the prior art, the purpose of this application is to provide an online parameter identification method and system for a permanent magnet synchronous motor that can improve the identification accuracy of all electrical parameters of the permanent magnet synchronous motor.

[0008] To achieve the above purpose, the following technical solutions are adopted in this application: An online parameter identification method for a permanent magnet synchronous motor, the online identification method includes: obtaining relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, the relevant variables include voltage, current, current differential, and electrical angular velocity, the multiple voltage vectors include a zero voltage vector and multiple effective voltage vectors, and establishing a mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of the multiple voltage vectors; Based on the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of multiple voltage vectors, and coordinate transformation, calculate the sine and cosine values of twice the electrical angle, the inductance intermediate variable value, and the initial value of the stator resistance when the permanent magnet synchronous motor is under the action of the zero voltage vector; to calculate the absolute values of the sine and cosine of the electrical angle, the inductance value, and multiple parameter matrices, the inductance value includes the quadrature-axis inductance value and the direct-axis inductance value; Select the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of the zero voltage vector, and the initial value of the stator resistance and multiple parameter matrices, and calculate the estimated sine and cosine values of the electrical angle when the permanent magnet synchronous motor is under the action of the zero voltage vector; and determine the polarities of the sine and cosine values of the electrical angle of the permanent magnet synchronous motor based on the estimated sine and cosine values of the electrical angle; Based on the absolute values of the sine and cosine of the electrical angle and the polarities of the sine and cosine values of the electrical angle, determine the accurate sine and cosine values of the electrical angle when the permanent magnet synchronous motor is under the action of the zero voltage vector; Based on the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle when the permanent magnet synchronous motor is under the action of the zero voltage vector, and the accurate sine and cosine values of the electrical angle and multiple parameter matrices when under the action of the zero voltage vector, calculate the final value of the resistance and the final value of the magnetic flux linkage of the permanent magnet synchronous motor.

[0009] Further, the expression for obtaining the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors and establishing the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of the multiple voltage vectors is as follows: ; ; ; Wherein, represents the axis voltage of the permanent magnet synchronous motor, represents the Axis voltage, Expressed as that of a permanent magnet synchronous motor Axis current, Expressed as that of a permanent magnet synchronous motor Axis current, Expressed as The differential of the current along the axis, Expressed as The differential of the current along the axis, Expressed as the electrical angular velocity of a permanent magnet synchronous motor, The unknown quantity expressed as the electrical angle of a permanent magnet synchronous motor, Expressed as the parameter matrix of a permanent magnet synchronous motor, Expressed as the parameter matrix of a permanent magnet motor, Expressed as the zero voltage vector, Expressed as the first effective voltage vector, Expressed as the second effective voltage vector, Expressed as the stator resistance value, Expressed as the flux linkage value.

[0010] Furthermore, the parameter matrix and the parameter matrix are calculated through the following expressions: ; ; ; ; wherein, is expressed as the direct-axis inductance value of a permanent magnet synchronous motor, is expressed as the quadrature-axis inductance value of a permanent magnet synchronous motor.

[0011] Furthermore, based on the mathematical relationships among the relevant variables of a permanent magnet synchronous motor under the action of multiple voltage vectors, the permanent magnet synchronous motor parameters and the electrical angle, as well as the coordinate transformation, an intermediate voltage equation is obtained, and the quantities related to voltage, current, current differential and the Park matrix in the intermediate voltage equation are replaced with the parameter , and the expressions for calculating the sine and cosine values of twice the electrical angle, the inductance intermediate variable and the initial resistance value when the permanent magnet synchronous motor is under the action of the zero voltage vector are as follows: ; ; ; wherein, is expressed as the parameter related to voltage, current, current differential and the Pdrk matrix, , ∈ {1, 2, 3, 4}, is expressed as the electrical angle when the permanent magnet motor is under the action of the zero voltage vector; is expressed as the sine value of twice the electrical angle when the permanent magnet synchronous motor is under the action of the zero voltage vector, is expressed as the cosine value of twice the electrical angle when the permanent magnet synchronous motor is under the action of the zero voltage vector, is expressed as the initial value of the stator resistance, and the absolute values of the sine and cosine of the electrical angle, the direct-axis inductance value and the quadrature-axis inductance value and the parameter matrix and the parameter matrix are expressed as follows: ; ; ; ; ; .

[0012] Further, based on the mathematical relationship between the Park matrix and the relevant variables under the action of multiple voltage vectors, the parameters of the permanent magnet synchronous motor and the electrical angle, an intermediate voltage equation is obtained, and the voltage, current, current differential and the quantities related to the Park matrix in the intermediate voltage equation are replaced with the parameter , and the expression of the intermediate voltage equation is as follows: ; ; wherein, is expressed as the sampling time difference between two samplings when the zero voltage vector and the first effective voltage vector act, is expressed as the sampling time difference between two samplings when the zero voltage vector and the second effective voltage vector act; is expressed as the Park matrix, ; replacing the quantities related to voltage, current, current differential and the Park matrix in the intermediate voltage equation with the parameter is expressed as follows: ; .

[0013] Further, when replacing the quantities related to voltage, current, current differential and the Park matrix in the intermediate voltage equation with the parameter , the expression of the Park matrix is as follows: ; ; Among them, .

[0014] Furthermore, based on the mathematical relationship between the relevant variables of the permanent magnet synchronous motor under the zero voltage vector, the parameters of the permanent magnet synchronous motor and the electrical angle, as well as the initial resistance value , parameter matrix and parameter matrix , the expressions for calculating the estimated values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor are as follows: ; ; ; ; Among them, is the initial value of the magnetic flux linkage, represents the estimated value of the sine of the electrical angle, represents the estimated value of the cosine of the electrical angle.

[0015] Furthermore, based on the absolute values of the sine and cosine of the electrical angle under the zero voltage vector and the polarities of the sine and cosine of the electrical angle under the zero voltage vector, the expressions for calculating the accurate values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor under the zero voltage vector are as follows: ; ; Among them, represents the accurate value of the sine of the electrical angle, represents the accurate value of the cosine of the electrical angle.

[0016] Furthermore, based on the mathematical relationship between the relevant variables under the zero voltage vector, the parameters of the permanent magnet synchronous motor and the electrical angle, as well as the accurate values of the sine and cosine of the electrical angle, parameter matrix and parameter matrix , the expressions for calculating the final resistance value and the final magnetic flux linkage value of the permanent magnet synchronous motor are as follows: ; Among them, represents the final resistance value, represents the final magnetic flux linkage value.

[0017] To achieve the above object, the present application adopts the following technical solutions: A permanent magnet synchronous motor parameter online identification system, which can execute the above-mentioned permanent magnet synchronous motor parameter online identification method.

[0018] The above-mentioned online parameter identification method and system for permanent magnet synchronous motors collect the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor under the action of zero voltage vectors and multiple effective voltage vectors, so as to accurately calculate the inductance value and the final electrical angle of the permanent magnet synchronous motor, and calculate the accurate final resistance value and the final permanent magnet flux linkage value of the permanent magnet synchronous motor. By calculating the inductance value, the final electrical angle value, the final resistance value, and the final flux linkage value, the influence of the electrical angle error obtained by sampling on the identification results of resistance, inductance, and flux linkage can be avoided, so as to improve the accuracy of permanent magnet synchronous motor parameter identification. At the same time, during the process of online parameter identification of the permanent magnet synchronous motor, there is no need to input additional excitation signals and accurate initial motor parameters, thus avoiding the deterioration of the motor operation performance caused by additional excitation signals or the influence of initial motor parameter errors on the parameter identification results, so as to further improve the accuracy of online parameter identification of the permanent magnet synchronous motor. Brief Description of the Drawings

[0019] Figure 1 It is a flowchart of the online parameter identification method for permanent magnet synchronous motors provided by an embodiment of the present application.

[0020] Figure 2 It is a sampling time diagram of voltage vectors provided by an embodiment of the present application.

[0021] Figure 3 It is a structural diagram of the online parameter identification system for permanent magnet synchronous motors provided by an embodiment of the present application. Detailed Embodiments

[0022] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the specific embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0023] It should be noted that the "first", "second", and similar terms used in the specification and claims of the present application do not indicate any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. "Multiple" or "several" means at least two. Unless otherwise specified, terms such as "front", "rear", "left", "right", "lower", and / or "upper" are only for convenience of description and are not limited to one position or a spatial orientation. "Including" or "comprising" and similar terms mean that the elements or objects appearing before "including" or "comprising" cover the elements or objects listed after "including" or "comprising" and their equivalents, and do not exclude other elements or objects. "Connecting" or "being connected" and similar terms are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0024] As used in the specification and appended claims of this application, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0025] As Figure 1 shown, this application provides an online identification method for the parameters of a permanent magnet synchronous motor. This method is used to identify the parameters of the permanent magnet synchronous motor in real time during operation, so as to achieve high-precision and high-robustness control of the permanent magnet synchronous motor.

[0026] The online identification method for the parameters of a permanent magnet synchronous motor includes the following steps: S11, obtaining relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors. The relevant variables include voltage, current, current differential and electrical angular velocity. The multiple voltage vectors include a zero voltage vector and multiple effective voltage vectors, and establishing a mathematical relationship between the relevant variables, the parameters of the permanent magnet synchronous motor and the electrical angle under the action of the multiple voltage vectors.

[0027] Through the above settings, a sufficient number of voltage equations about the action of different voltage vectors can be constructed to represent the mathematical relationship between the relevant variables, the parameters of the permanent magnet synchronous motor and the electrical angle under the action of different voltage vectors, so as to avoid the under-rank problem when identifying the parameters of multiple permanent magnet synchronous motors, thereby increasing the number of parameters of the permanent magnet synchronous motor identified by the online identification method, and further improving the adaptability of the online identification method for identifying the parameters of the permanent magnet synchronous motor.

[0028] At the same time, by inputting the relevant variables under the action of different voltage vectors, a sufficient number of voltage equations under the action of voltage vectors can be constructed, so that there is no need to input the quantities related to the motor parameters, so as to avoid setting the initial motor parameters to increase the rank of the equations, and further avoid the influence of the error of the initial motor parameters on the parameter identification of the permanent magnet synchronous motor, so as to improve the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor. And, there is no need to input additional excitation signals, thus avoiding the deterioration of the performance of the permanent magnet synchronous motor during operation by the additional excitation signals, and further improving the stability of the operation of the permanent magnet synchronous motor.

[0029] In addition, the electrical angle is set as an unknown parameter, and the accurate electrical angle is obtained by calculation, so that there is no need to input the specific electrical angle to construct the voltage equation, so as to avoid the influence of the error of the electrical angle on the result of the parameter identification of the permanent magnet synchronous motor, and further improve the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor.

[0030] In this application, according to the number of permanent magnet synchronous motor parameters to be identified, relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors can be sampled to establish a voltage equation corresponding to the number of permanent magnet synchronous motor parameters, and then a switching model of the permanent magnet synchronous motor can be established based on the voltage equation, that is, a switching model is established to calculate the permanent magnet synchronous motor parameters, thereby facilitating the improvement of the efficiency and accuracy of subsequent permanent magnet synchronous motor parameter identification.

[0031] Exemplarily, in this application, the permanent magnet synchronous motor is driven by a voltage source inverter (VSI), and the output voltage is a chopped wave obtained through space vector pulse width modulation (SVPWM) to achieve the control of the permanent magnet synchronous motor.

[0032] As Figure 2 shown, this application also provides a sampling time diagram of voltage vectors. In the figure represents the zero voltage vector, represents the first effective voltage vector, represents the second effective voltage vector, , represents axis. The space is divided into six sectors (Ⅰ to Ⅵ) by six effective voltage vectors, and the output voltage of each sector is generated by the joint action of the zero voltage vector , the first effective vector and the second effective voltage vector . Within one pulse width modulation (PWM) period, the zero voltage vector, the first effective voltage vector, and the second effective voltage vector are sampled. The sampling time points of the zero voltage vector, the first effective voltage vector, and the second effective voltage vector are all intermediate time points. Moreover, when sampling within one PWM period, in any sector, when the same voltage vector acts, the voltage on the axis is constant; when different voltage vectors act, the voltage values on the axis are not equal.

[0033] It should be noted that this application does not limit the specific moments of the sampling time points of multiple voltage vectors, and only needs to satisfy the establishment of the voltage equation.

[0034] This application also provides a table of voltage values of the permanent magnet synchronous motor when it is in different sectors and under the action of different voltage vectors.

[0035]

[0036] Among them, is the DC bus voltage, represents the switching state of the phase of the three-phase bridge arm of the VSI, represents the switching state of the phase of the three-phase bridge arm of the VSI, represents the switching state of the phase of the three-phase bridge arm of the VSI, = 1 indicates that the upper bridge arm of the phase of the three-phase bridge arm is turned on and the lower bridge arm is turned off, = 1 indicates that the upper bridge arm of the phase of the three-phase bridge arm is turned on and the lower bridge arm is turned off, = 1 indicates that the upper bridge arm of the phase of the three-phase bridge arm is turned on and the lower bridge arm is turned off, = 0 indicates that the lower bridge arm of the phase of the three-phase bridge arm is turned on and the upper bridge arm is turned off, = 0 indicates that the lower bridge arm of the phase of the three-phase bridge arm is turned on and the upper bridge arm is turned off, = 0 indicates that the lower bridge arm of the phase of the three-phase bridge arm is turned on and the upper bridge arm is turned off. I to VI represent different sectors of the permanent magnet synchronous motor; is represented as the voltage of the is represented as the voltage of the 0 is represented as the zero voltage vector, Z 7 is represented as the zero voltage vector.

[0037] S12, based on the mathematical relationships among relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of multiple voltage vectors, as well as coordinate transformation, calculates the sine and cosine values of the double electrical angle, the intermediate inductance variable value, and the initial value of the stator resistance when the permanent magnet synchronous motor is under the action of the zero voltage vector; to calculate the absolute values of the sine and cosine of the electrical angle, the inductance value, and multiple parameter matrices, and the inductance value includes the quadrature-axis inductance value and the direct-axis inductance value.

[0038] Through the above settings, during the process of calculating the inductance value of the permanent magnet synchronous motor, it is possible to avoid inputting the initial motor parameters to construct the voltage equation, thereby avoiding the interference of the errors of the initial motor parameters on the calculation of the inductance value, and further improving the accuracy of the calculation of the inductance value, so as to improve the accuracy of identifying the inductance of the permanent magnet synchronous motor by the online identification method.

[0039] In this application, by establishing the mathematical relationships between the electrical variables under the action of the first effective voltage vector and the second voltage vector and the permanent magnet synchronous motor parameters, as well as coordinate transformation, a first model can be obtained. That is, through the first model, the absolute values of the sine and cosine of the electrical angle, the inductance value, the initial value of the stator resistance, and multiple parameter matrices of the permanent magnet synchronous motor can be calculated.

[0040] S13: Select the relevant variables under the action of the zero voltage vector, the mathematical relationships between the permanent magnet synchronous motor parameters and the electrical angle, the initial value of the stator resistance, and multiple parameter matrices, and calculate the estimated values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts; and determine the polarities of the sine and cosine values of the electrical angle of the permanent magnet synchronous motor based on the estimated values of the sine and cosine of the electrical angle.

[0041] Through the above settings, in the process of constructing the voltage equation to calculate the estimated values of the sine and cosine of the electrical angle, it is possible to avoid setting the initial motor parameters to construct the voltage equation, thereby avoiding the influence of the errors of the initial motor parameters on the accuracy of the estimated values of the sine and cosine of the electrical angle, so as to improve the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor.

[0042] At the same time, by calculating the estimated values of the sine and cosine of the electrical angle to determine the polarities of the sine and cosine values of the electrical angle, the accuracy of obtaining the electrical angle of the permanent magnet synchronous motor in the subsequent process can be improved, which is conducive to improving the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor in the subsequent process.

[0043] In this application, the mathematical relationships between the relevant variables of the permanent magnet synchronous motor under the action of the zero voltage vector, the permanent magnet synchronous motor parameters and the electrical angle are represented by the voltage equation of the permanent magnet synchronous motor under the action of the zero voltage vector. Thus, a second model can be established through the voltage equation of the permanent magnet synchronous motor under the action of the zero voltage vector, the absolute values of the sine and cosine of the electrical angle calculated by the first model, and the initial value of the stator resistance. That is, through the second model, the absolute values of the sine and cosine of the electrical angle under the action of the zero voltage vector can be calculated.

[0044] S14: Based on the absolute values of the sine and cosine of the electrical angle and the polarities of the sine and cosine values of the electrical angle, determine the accurate values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts.

[0045] The electrical angle of the existing permanent magnet synchronous motor is generally obtained by sensor detection. However, due to factors such as the detection accuracy of the sensor, the installation error, and the change of the operating conditions of the permanent magnet synchronous motor during operation, there are errors in the electrical angle of the permanent magnet synchronous motor detected by the sensor.

[0046] Through the above settings, obtaining the electrical angle of the permanent magnet synchronous motor by calculation can avoid the errors when the sensor obtains the electrical angle of the permanent magnet synchronous motor, thereby improving the accuracy of obtaining the electrical angle of the permanent magnet synchronous motor, which is conducive to improving the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor in the subsequent process.

[0047] Meanwhile, the accurate values of the sine and cosine of the electrical angle are obtained based on the absolute values of the sine and cosine of the electrical angle and the polarities of the sine and cosine values of the electrical angle, which can remove the uncertainties in the numerical value and polarity of the electrical angle, so as to obtain the accurate value of the electrical angle of the permanent magnet synchronous motor, and further improve the accuracy of calculating the final resistance value and the final flux linkage value of the permanent magnet synchronous motor by the subsequent online identification method, which is conducive to improving the accuracy of identifying the parameters of the permanent magnet synchronous motor by the online identification parameters.

[0048] S15, based on the mathematical relationship between the relevant variables when the zero voltage vector acts on the permanent magnet synchronous motor, the parameters of the permanent magnet synchronous motor and the electrical angle, as well as the accurate values of the sine and cosine of the electrical angle and multiple parameter matrices when the zero voltage vector acts, calculate the final resistance value and the final flux linkage value of the permanent magnet synchronous motor.

[0049] Through the above settings, after determining the accurate value of the electrical angle, substitute the voltage, current, current differential, electrical angular velocity and the accurate values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector into the voltage equation of the permanent magnet synchronous motor under the action of the zero voltage vector. According to the above voltage equation, the accurate final resistance value and the final flux linkage value of the permanent magnet synchronous motor can be directly calculated and obtained, so as to improve the accuracy of identifying the resistance value and the flux linkage value of the permanent magnet synchronous motor by the online identification method.

[0050] In this application, a third model is established based on the mathematical relationship between the relevant variables when the zero voltage vector acts on the permanent magnet synchronous motor, the parameters of the permanent magnet synchronous motor and the electrical angle, as well as the accurate values of the sine and cosine of the electrical angle and multiple parameter matrices when the zero voltage vector acts, that is, the third model is used to calculate the final resistance value and the final flux linkage value of the permanent magnet synchronous motor. By calculating the final resistance value and the final flux linkage value of the permanent magnet synchronous motor in the way of the third model, the final resistance value and the final flux linkage value of the permanent magnet synchronous motor can be accurately obtained, and further the accuracy of identifying the parameters of the permanent magnet synchronous motor by the online identification method can be improved.

[0051] It should be noted that this application does not limit the parameters of the permanent magnet synchronous motor to be identified, and only needs to meet the requirement of improving the accuracy of the permanent magnet synchronous motor control.

[0052] As an implementation manner, the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors are obtained, and the expression of the mathematical relationship between the relevant variables under the action of multiple voltage vectors, the parameters of the permanent magnet synchronous motor and the electrical angle is as follows: (Formula 1); (Formula 2); (Formula 3); Among them, is expressed as the Axis voltage, Expressed as that of a permanent magnet synchronous motor Axis voltage, Expressed as that of a permanent magnet synchronous motor Axis current, Expressed as that of a permanent magnet synchronous motor Axis current, Expressed as Differential of the current of the axis, Expressed as Differential of the current of the axis, Expressed as the electrical angular velocity of a permanent magnet synchronous motor, Unknown quantity expressed as the electrical angle of a permanent magnet synchronous motor, Expressed as the parameter matrix of a permanent magnet synchronous motor, Expressed as the parameter matrix of a permanent magnet motor, Expressed as a zero voltage vector, Expressed as a first effective voltage vector, Expressed as a second effective voltage vector, Expressed as the stator resistance value, Expressed as the flux linkage value.

[0053] Through the above settings, within one PWM cycle, samples are taken of the permanent magnet synchronous motor under the action of the first effective voltage vector, the second effective voltage vector, and the zero voltage vector, and data during its operation is collected, including The voltage, current, current differential of the axis, and The axis voltage, current, current differential, and electrical angular velocity to construct a full-rank voltage equation to facilitate subsequent calculation of the parameters of the permanent magnet synchronous motor, thereby improving the accuracy of the online identification method for identifying the permanent magnet synchronous motor.

[0054] As an implementation method, the parameter matrix And the parameter matrix Are calculated through the following expressions:

[0055] (Equation 4); ; (Equation 5); Among them, Expressed as the direct-axis inductance value of a permanent magnet synchronous motor, Expressed as the quadrature-axis inductance value of a permanent magnet synchronous motor.

[0056] As an implementation, based on the mathematical relationships among the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle, as well as coordinate transformation, an intermediate voltage equation is obtained, and the quantities related to voltage, current, current differential, and the Park matrix in the intermediate voltage equation are replaced with parameters , and the expressions for the sine and cosine values of twice the electrical angle, the intermediate inductance variable, and the initial resistance value of the permanent magnet synchronous motor when the zero voltage vector acts are calculated as follows: (Equation 6); (Equation 7); (Equation 8); Among them, represents the parameters related to voltage, current, current differential, and the Park matrix, , ∈{1, 2, 3, 4}, represents the electrical angle of the permanent magnet motor when the zero voltage vector acts; represents the sine value of twice the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts, represents the cosine value of twice the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts, represents the initial value of the stator resistance. Determine the absolute values of the sine and cosine of the electrical angle, the direct-axis inductance value , the quadrature-axis inductance value , the parameter matrix and the parameter matrix The expressions are as follows:

[0057] (Equation 9); ; (Equation 10); ; (Equation 11).

[0058] In this application, according to the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor, a corresponding voltage equation is established, and then a first model for parameter identification of the permanent magnet synchronous motor is established based on the voltage equation, that is, a first model is established through Equation 6 to calculate accurate inductance values, absolute sine and cosine values, and multiple parameter matrices, so as to improve the accuracy of subsequent parameter identification of the permanent magnet synchronous motor.

[0059] As an implementation manner, based on the mathematical relationship between the Park matrix, relevant variables under the action of multiple voltage vectors, permanent magnet synchronous motor parameters, and electrical angle, an intermediate voltage equation is obtained, and the voltage, current, current differential, and quantities related to the Park matrix in the intermediate voltage equation are replaced with parameters , and the expression of the intermediate voltage equation is as follows: (Equation 12); (Equation 13); Wherein, represents the sampling time difference between two samplings when the zero voltage vector and the first effective voltage vector act, represents the sampling time difference between two samplings when the zero voltage vector and the second effective voltage vector act; represents the Park matrix, ; replacing the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with parameters the expression is as follows: (Equation 14); (Equation 15).

[0060] Exemplarily, in the present application, the calculation process of the common parameter is as follows: Define the Park matrix, and then use this matrix to convert the electrical angle in the voltage equation under the action of the first effective voltage and the second effective voltage in S11 into the electrical angle under the zero voltage vector to obtain the first voltage vector equation set, and its specific expression is as follows: (Equation 16); (Equation 17); Then, multiply the voltage vector equation under the action of the first effective voltage vector in the first voltage vector equation set on the left by , and multiply the voltage vector equation under the action of the second effective voltage vector in the first voltage vector equation set on the left by , to obtain the expression of the following second voltage vector equation set: (Equation 18); (Equation 19).

[0061] Since the present application samples the permanent magnet synchronous motor within a pulse width modulation (PWM) period, and the time of a pulse width modulation (PWM) period is very short, the electrical angular velocity of the permanent magnet synchronous motor basically does not change, that is Therefore, by subtracting the voltage equation under the zero voltage vector in S11 from the second voltage vector equation set, the expression of the intermediate voltage equation can be obtained: (Equation 20); (Equation 21).

[0062] Then, substitute the quantities related to voltage, current, current differential, and Park matrix in the above third voltage vector equation set with to obtain the expression of the following fourth voltage vector equation set: (Equation 22); (Equation 23); Finally, during a PWM period, sample the permanent magnet synchronous motor under different voltage vectors to obtain voltage, current, current differential, electrical angular velocity, and sampling time difference, and combine with the fourth voltage vector equation set to obtain the common parameters . Through the above settings, during the calculation of the common parameters , the voltage, current, current differential, and electrical angular velocity are all parameters obtained by sampling the permanent magnet synchronous motor, so additional excitation signals or initial parameters can be avoided, thereby improving the accuracy of the parameters , which is conducive to improving the accuracy of online identification of permanent magnet synchronous motor parameters.

[0063] As an implementation manner, when replacing the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with the parameter , the expression of the Park matrix is as follows:

[0064] (Equation 24); where .

[0065] As an implementation manner, based on the mathematical relationship between the relevant variables of the permanent magnet synchronous motor under the zero voltage vector, the permanent magnet synchronous motor parameters and the electrical angle, as well as the initial value of the resistance , the parameter matrix and the parameter matrix , the expressions for estimating the sine and cosine values of the electrical angle of the permanent magnet synchronous motor are calculated as follows: (Equation 25); (Equation 26); ; (Equation 27); Wherein, is the initial value of the magnetic flux linkage, represents the estimated value of the sine value of the electrical angle, represents the estimated value of the cosine of the electrical angle.

[0066] Through the above settings, substituting the initial value of the magnetic flux linkage, as well as the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor under the action of the zero voltage vector into Equation 25, the estimated values of the sine and cosine values of the electrical angle can be calculated, so as to accurately judge the polarity of the electrical angle of the permanent magnet synchronous motor with the help of the estimated values of the sine and cosine values of the electrical angle, which is beneficial to improving the accuracy of the subsequent obtained electrical angle, and further improving the accuracy of the online identification of the parameters of the permanent magnet synchronous motor.

[0067] In this application, according to the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor, a corresponding voltage equation is established, and then a second parameter identification model of the permanent magnet synchronous motor is established according to the voltage equation, that is, accurate estimated values of the sine and cosine values of the electrical angle can be calculated through Equation 25, which is beneficial to improving the accuracy of the subsequent parameter identification of the permanent magnet synchronous motor.

[0068] As an implementation manner, based on the absolute values of the sine and cosine of the electrical angle under the action of the zero voltage vector and the polarities of the sine and cosine values of the electrical angle under the action of the zero voltage vector, the expressions for calculating the accurate sine and cosine values of the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector are as follows: ; (Equation 28); Wherein, represents the accurate sine value of the electrical angle, represents the accurate cosine value of the electrical angle.

[0069] Through the above settings, the absolute values of the sine and cosine of the electrical angle and the polarities of the sine and cosine values of the electrical angle under the action of the zero voltage vector are obtained, and then the corresponding calculation equations are selected according to the polarities of the sine and cosine values of the electrical angle, so as to obtain the sine function and cosine function of the accurate electrical angle value, so as to obtain the accurate electrical angle value, and further improve the accuracy of calculating the accurate electrical angle value, which is beneficial to improving the accuracy of the online identification method of the parameters of the permanent magnet synchronous motor.

[0070] As an implementation manner, based on the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters and electrical angle under the action of the zero voltage vector, as well as the accurate sine and cosine values of the electrical angle, parameter matrix and parameter matrix , the expressions for calculating the final value of the resistance and the final value of the magnetic flux linkage of the permanent magnet synchronous motor are as follows: (Equation 29); Wherein, is represented as the final resistance value, is represented as the final flux linkage value.

[0071] Through the above settings, after determining the accurate value of the electrical angle, substitute the voltage, current, and current differential under the action of the zero voltage vector to construct the corresponding equations, so as to obtain the accurate final resistance value and final flux linkage value, which is conducive to improving the accuracy of the online identification method of the permanent magnet synchronous motor parameters.

[0072] In this application, according to the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor, establish the corresponding voltage equation, and then establish the third model for parameter identification of the permanent magnet synchronous motor according to the voltage equation. The accurate final resistance value and final flux linkage value can be calculated through Formula 29, which is conducive to improving the accuracy of parameter identification of the permanent magnet synchronous motor.

[0073] As Figure 3 shown, this application also provides an online identification system for the parameters of a permanent magnet synchronous motor, and this online identification system can execute the online identification method for the parameters of the permanent magnet synchronous motor.

[0074] Through the above settings, a sufficient number of voltage equations regarding the action of different voltage vectors can be constructed to represent the mathematical relationship between the relevant variables, the parameters of the permanent magnet synchronous motor, and the electrical angle under the action of different voltage vectors, so as to avoid the under-rank problem when identifying the parameters of multiple permanent magnet synchronous motors.

[0075] At the same time, during the process of identifying the parameters of the permanent magnet synchronous motor, input the voltage, current, current differential, and electrical angular velocity to construct the voltage equation, so as to avoid inputting the quantities related to the motor parameters, so as to avoid setting the initial motor parameters to increase the rank of the equation, and further avoid the influence of the error of the initial motor parameters on the parameter identification of the permanent magnet synchronous motor, which is conducive to improving the accuracy of the online identification system for identifying the parameters of the permanent magnet synchronous motor.

[0076] Moreover, during the process of identifying the parameters of the permanent magnet synchronous motor, set the electrical angle as an unknown parameter for calculation, so that it is not necessary to input the electrical angle, so as to avoid the influence of the electrical angle error on the parameter identification of the permanent magnet synchronous motor, and further improve the accuracy of the online identification system for identifying the parameters of the permanent magnet synchronous motor.

[0077] In addition, during the process of identifying the parameters of the permanent magnet synchronous motor, there is no need to input an additional excitation signal to construct a full-rank voltage equation, so as to avoid the interference of the additional excitation signal on the operating state of the permanent magnet synchronous motor, and further improve the stability of the permanent magnet synchronous motor during operation.

[0078] In this application, the online identification system includes a switching model, a first model, a second model, and a third model. By obtaining the voltage, current, current differential, and electrical angular velocity of the permanent magnet synchronous motor under the action of the zero voltage vector and multiple effective voltage vectors, the inductance value, resistance value, and magnetic flux value of the permanent magnet synchronous motor can be obtained through the calculation of the above models.

[0079] This application can achieve the following technical effects: avoiding the influence of position sensor errors, avoiding excitation signal injection, and breaking through the initial parameter limitations, so as to realize the online accurate identification of all electrical parameters, and further improve the performance of the permanent magnet synchronous motor control algorithm.

[0080] It should be understood that for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations shall fall within the protection scope of the appended claims of this application.

Claims

1. An online identification method for permanent magnet synchronous motor parameters, characterized in that: Online identification methods include: Acquire relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, wherein the relevant variables include voltage, current, current differential and electrical angular velocity, wherein the multiple voltage vectors include a zero voltage vector and multiple effective voltage vectors, and establish a mathematical relationship between the relevant variables under the action of the multiple voltage vectors, the permanent magnet synchronous motor parameters and the electrical angle; Based on the relevant variables under the action of multiple voltage vectors, the mathematical relationship between the permanent magnet synchronous motor parameters and the electrical angle, and the coordinate transformation, the sine and cosine values ​​of twice the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts, the intermediate variable value of the inductance, and the initial value of the stator resistance are calculated; the absolute value of the sine and cosine of the electrical angle, the inductance value, and multiple parameter matrices are calculated, and the inductance value includes the quadrature-axis inductance value and the direct-axis inductance value; Select relevant variables under the action of zero voltage vector, the mathematical relationship between the permanent magnet synchronous motor parameters and the electrical angle, the initial value of the stator resistance and multiple parameter matrices, calculate the estimated sine and cosine values ​​of the electrical angle of the permanent magnet synchronous motor under the action of zero voltage vector; and determine the polarity of the sine and cosine values ​​of the electrical angle of the permanent magnet synchronous motor based on the estimated sine and cosine values ​​of the electrical angle; Based on the absolute value of the electrical angle sine and cosine and the polarity of the electrical angle sine and cosine, the accurate value of the electrical angle sine and cosine of the permanent magnet synchronous motor when the zero voltage vector acts is determined; Based on the relevant variables when the permanent magnet synchronous motor has zero voltage vector action, the mathematical relationship between the permanent magnet synchronous motor parameters and the electrical angle, the accurate sine and cosine values ​​of the electrical angle when the zero voltage vector action is applied and multiple parameter matrices, the final resistance value and the final flux linkage value of the permanent magnet synchronous motor are calculated.

2. The method for online identification of permanent magnet synchronous motor parameters according to claim 1, characterized in that: The expression for obtaining the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors and establishing the mathematical relationship between the relevant variables under the action of multiple voltage vectors, the parameters of the permanent magnet synchronous motor and the electrical angle is as follows: ； ； ； in, Represented as a permanent magnet synchronous motor Shaft voltage, Represented as a permanent magnet synchronous motor Shaft voltage, Represented as a permanent magnet synchronous motor Shaft current, Represented as a permanent magnet synchronous motor Shaft current, Expressed as The current differential of the axis, Expressed as The current differential of the axis, Expressed as the electrical angular velocity of the permanent magnet synchronous motor, The unknown quantity represented as the electrical angle of the permanent magnet synchronous motor, Expressed as the parameter matrix of permanent magnet synchronous motor, Expressed as the parameter matrix of the permanent magnet motor, Represented as zero voltage vector, Expressed as the first effective voltage vector, Expressed as the second effective voltage vector, Expressed as the stator resistance value, Expressed as a flux linkage value.

3. The method for online identification of permanent magnet synchronous motor parameters according to claim 2, characterized in that: The parameter matrix and the parameter matrix Calculated by the following expression: ； ； ； ； in, Expressed as the direct-axis inductance value of the permanent magnet synchronous motor, Expressed as the quadrature-axis inductance of the permanent magnet synchronous motor.

4. The method for online identification of permanent magnet synchronous motor parameters according to claim 1, characterized in that: The method is based on the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, the mathematical relationship between the permanent magnet synchronous motor parameters and the electrical angle, and the coordinate transformation, to obtain the intermediate voltage equation, and replace the quantities related to the voltage, current, current differential and Park matrix in the intermediate voltage equation with parameters , the expressions for calculating the sine and cosine values ​​of the double electrical angle, the intermediate inductance variable and the initial resistance value of the permanent magnet synchronous motor under the action of zero voltage vector are as follows: ； ； ； ； in, Expressed as parameters related to voltage, current, current differential and Park matrix, , ∈{1, 2, 3,4}, It is expressed as the electrical angle of the permanent magnet motor when the voltage vector acts at zero; It is expressed as the sine value of twice the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts. It is expressed as the cosine value of twice the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts. It is expressed as the initial value of stator resistance, the absolute value of sine and cosine of electrical angle, and the direct axis inductance value , quadrature axis inductance , parameter matrix and the parameter matrix The expression is as follows: ； ； ； ； ； 。 5. The method for online identification of permanent magnet synchronous motor parameters according to claim 4, characterized in that: Based on the Park matrix and the mathematical relationship between the relevant variables under the action of multiple voltage vectors, the permanent magnet synchronous motor parameters and the electrical angle, the intermediate voltage equation is obtained, and the voltage, current and current differential in the intermediate voltage equation and the quantities related to the Park matrix are replaced by parameters , the expression of the intermediate voltage equation is as follows: ； ； in, It is expressed as the sampling time difference between the two samplings when the zero voltage vector and the first effective voltage vector act. It is expressed as the sampling time difference between two samplings when the zero voltage vector and the second effective voltage vector act; Expressed as Park matrix, ; Replace the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with parameters The expression is as follows: .

6. The method for online identification of permanent magnet synchronous motor parameters according to claim 4, characterized in that: The intermediate voltage equation is replaced by the parameters related to voltage, current, current differential and Park matrix. When , the expression of Park matrix is ​​as follows: ； ； in, .

7. The method for online identification of permanent magnet synchronous motor parameters according to claim 1, characterized in that: The mathematical relationship between the relevant variables of the permanent magnet synchronous motor under the action of zero voltage vector, the parameters of the permanent magnet synchronous motor and the electrical angle, and the initial value of the resistance , parameter matrix and the parameter matrix , the expression for calculating the estimated value of the electrical angle sine and cosine value of the permanent magnet synchronous motor is as follows: ； ； ； ； in, is the initial value of magnetic flux, Expressed as an estimate of the sine of the electrical angle, Expressed as an estimate of the electrical angle cosine.

8. The method for online identification of permanent magnet synchronous motor parameters according to claim 1, characterized in that: The expression for calculating the accurate value of the sine and cosine of the electrical angle under the action of the zero voltage vector based on the absolute value of the sine and cosine of the electrical angle under the action of the zero voltage vector and the polarity of the sine and cosine of the electrical angle under the action of the zero voltage vector is as follows: ； ； in, Expressed as the exact value of the electrical angle sine, Expressed as the exact value of the electrical angle cosine.

9. The method for online identification of permanent magnet synchronous motor parameters according to claim 1, characterized in that: The mathematical relationship between the relevant variables under the action of zero voltage vector, the permanent magnet synchronous motor parameters and the electrical angle, and the accurate value of the electrical angle sine and cosine, the parameter matrix and the parameter matrix , the expressions for calculating the final resistance value and the final flux linkage value of the permanent magnet synchronous motor are as follows: ； in, Expressed as the final resistance value, Expressed as the final value of magnetic flux.

10. An online identification system for permanent magnet synchronous motor parameters, characterized in that: The online identification system can execute the online identification method of permanent magnet synchronous motor parameters as described in any one of claims 1 to 9.

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