An Online Identification Method and System for the Parameters of a Permanent Magnet Synchronous Motor

Abstract

The present application discloses an online identification method and system for permanent magnet synchronous motor parameters. The online identification method includes: obtaining relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, and establishing a mathematical relationship between the relevant variables, the permanent magnet synchronous motor parameters, and the electrical angle; based on the above mathematical relationship and coordinate transformation, calculating the initial value of the stator resistance, the inductance value, multiple parameter matrix values, and the absolute values of the sine and cosine of the electrical angle; based on the above mathematical relationship, as well as the initial value of the stator resistance and multiple parameter matrices, determining the polarities of the sine and cosine values of the electrical angle; calculating the accurate sine and cosine values of the electrical angle according to the absolute values and polarities of the sine and cosine of the electrical angle; finally, based on the above mathematical relationship under the zero voltage vector, as well as the accurate sine and cosine values and multiple parameter matrices, calculating the final value of the resistance and the final value of the magnetic flux linkage. The system can execute the above online identification method. Through the above settings, 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 on-line 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 parameters of the permanent magnet synchronous motors 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-varying properties. Currently, on-line parameter identification methods are generally used to identify the parameters of permanent magnet synchronous motors in real time, and the on-line 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 on-line identification accuracy of permanent magnet synchronous motor parameters. In the existing process of on-line 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 on-line 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 underdetermined rank problem 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 parameters of the permanent magnet synchronous motor. However, if excitation signals are injected, non-negligible torque and speed pulsations 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 grouped identification, and flux-linkage-free models. The nominal value method and the grouped identification method are both affected by the accuracy of the initial motor parameters during on-line parameter identification of permanent magnet synchronous motors, thus affecting the accuracy of the permanent magnet synchronous motor parameter identification result; the flux-linkage-free model can only realize on-line 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 the present 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 present application adopts the following technical solutions:

[0009] 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;

[0010] 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 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, the inductance value includes the quadrature-axis inductance value and the direct-axis inductance value;

[0011] 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 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.

[0012] Based on the absolute values of the sine and cosine of the electrical angle and the polarity 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;

[0013] 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.

[0014] Furthermore, 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:

[0015] ;

[0016] ;

[0017] ;

[0018] Among them, is expressed as the shaft voltage of the permanent magnet synchronous motor shaft voltage, is expressed as the shaft voltage of the permanent magnet synchronous motor shaft voltage, is expressed as the shaft current of the permanent magnet synchronous motor shaft current, is expressed as the shaft current of the permanent magnet synchronous motor shaft current, is expressed as the current differential of the shaft, is expressed as the current differential of the shaft, is expressed as the electrical angular velocity of the permanent magnet synchronous motor, is expressed as the unknown quantity of the electrical angle of the permanent magnet synchronous motor, is expressed as the parameter matrix of the permanent magnet synchronous motor, is expressed as the parameter matrix of the permanent magnet motor, is expressed as the zero voltage vector, is expressed as the first effective voltage vector, is expressed as the second effective voltage vector, is expressed as the stator resistance value, is expressed as the flux linkage value.

[0019] Furthermore, the parameter matrix and the parameter matrix are calculated by the following expressions:

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] Among them, is expressed as the direct-axis inductance value of the permanent magnet synchronous motor, is expressed as the quadrature-axis inductance value of the permanent magnet synchronous motor.

[0025] Furthermore, 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 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 parameters , the expressions for calculating the sine and cosine values of twice the electrical angle, the inductance intermediate variable, and the initial resistance value of the permanent magnet synchronous motor under the action of the zero voltage vector are as follows:

[0026] ;

[0027] ;

[0028] ;

[0029] Among them, represents a parameter related to voltage, current, current differential, and the Pdrk matrix, , ∈{1, 2, 3, 4}, represents the electrical angle of the permanent magnet motor under the action of the zero voltage vector; represents the sine value of twice the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector, represents the cosine value of twice the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector, represents the initial value of the stator resistance, and the expressions for determining the absolute values of the sine and cosine of the electrical angle, the direct-axis inductance value and the quadrature-axis inductance value , the parameter matrix and the parameter matrix are as follows:

[0030] ;

[0031] ;

[0032] ;

[0033] ;

[0034] ;

[0035] .

[0036] Furthermore, based on the mathematical relationship between the Park matrix, 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:

[0037] ;

[0038] ;

[0039] Among them, 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, ; Replace the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with parameters The expressions are as follows:

[0040] ;

[0041] .

[0042] Furthermore, when replacing the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with parameters The expression of the Park matrix is as follows:

[0043] ;

[0044] ;

[0045] Among them, .

[0046] Furthermore, 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 of the permanent magnet synchronous motor, and the initial resistance value , parameter matrix and parameter matrix , the expressions for calculating the estimated values of the sine and cosine values of the electrical angle of the permanent magnet synchronous motor are as follows:

[0047] ;

[0048] ;

[0049] ;

[0050] ;

[0051] Among them, 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.

[0052] Further, the expression 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 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 is as follows:

[0053] ;

[0054] ;

[0055] Among them, represents the accurate sine value of the electrical angle, represents the accurate cosine value of the electrical angle.

[0056] Further, based on the mathematical relationships among the relevant variables, the parameters of the permanent magnet synchronous motor, and the electrical angle under the action of the zero voltage vector, as well as the accurate sine and cosine values of the electrical angle and the parameter matrices 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:

[0057] ;

[0058] Among them, represents the final resistance value, represents the final flux linkage value.

[0059] To achieve the above object, the present application adopts the following technical solution:

[0060] A permanent magnet synchronous motor parameter online identification system, which can execute the above-mentioned online identification method of the permanent magnet synchronous motor parameters.

[0061] The above-mentioned online identification method and system for the parameters of the permanent magnet synchronous motor collect 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, so as to accurately calculate the inductance value and the final electrical angle value of the permanent magnet synchronous motor, and calculate the accurate final resistance value and the 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 flux linkage value, the influence of the electrical angle error obtained by sampling on the identification results of the resistance, inductance, and flux linkage can be avoided, so as to improve the accuracy of the permanent magnet synchronous motor parameter identification. At the same time, during the process of online identification of the permanent magnet synchronous motor parameters, there is no need to input additional excitation signals and accurate initial motor parameters, thereby avoiding the deterioration of the motor operation performance caused by the additional excitation signals or the influence of the initial motor parameter errors on the parameter identification results, so as to further improve the accuracy of the online parameter identification of the permanent magnet synchronous motor. Description of the Drawings

[0062] Figure 1It is a flowchart of the online identification method for the parameters of the permanent magnet synchronous motor provided by the embodiment of the present application.

[0063] Figure 2 It is a sampling time diagram of the voltage vector provided by the embodiment of the present application.

[0064] Figure 3 It is a structural diagram of the online identification system for the parameters of the permanent magnet synchronous motor provided by the embodiment of the present application. Detailed implementation manners

[0065] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the specific implementation manners of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the implementation manners of the present application.

[0066] It should be noted that the "first", "second" and similar terms used in the specification and claims of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the similar terms such as "a" or "one" do not denote a quantity limitation, but mean that there is at least one. "Multiple" or "several" means at least two. Unless otherwise indicated, the similar 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. The terms such as "comprising" or "including" mean that the elements or objects appearing before "comprising" or "including" cover the elements or objects listed after "comprising" or "including" and their equivalents, and do not exclude other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0067] The singular forms of "a", "" and "the" used in the specification and appended claims of the present application are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term " / and / " as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0068] As Figure 1 shown, the present application provides an online identification method for the parameters of a permanent magnet synchronous motor, and this method is used to identify the parameters during the operation of the permanent magnet synchronous motor in real time, so as to achieve high-precision and high-robustness control of the permanent magnet synchronous motor.

[0069] The online identification method for the parameters of the permanent magnet synchronous motor includes the following steps:

[0070] S11. Obtain 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 establish 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.

[0071] 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 of the permanent magnet synchronous motor under the action of different voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle, 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.

[0072] At the same time, by inputting the relevant variables under the action of different voltage vectors, voltage equations under the action of a sufficient number of voltage vectors can be constructed, thus eliminating the need to input quantities related to the motor parameters to avoid setting initial motor parameters to increase the rank of the equations, and further avoiding 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. Moreover, there is no need to input additional excitation signals, thus avoiding the deterioration of the performance of the permanent magnet synchronous motor during operation caused by the additional excitation signals, and further improving the stability of the operation of the permanent magnet synchronous motor.

[0073] In addition, set the electrical angle as an unknown parameter and obtain the accurate electrical angle through calculation, 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.

[0074] In this application, according to the number of parameters of the permanent magnet synchronous motor to be identified, relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors can be sampled to establish voltage equations corresponding to the number of parameters of the permanent magnet synchronous motor, and then a switching model of the permanent magnet synchronous motor can be established based on the voltage equations, that is, a switching model is established to calculate the parameters of the permanent magnet synchronous motor, thereby facilitating the improvement of the efficiency and accuracy of subsequent parameter identification of the permanent magnet synchronous motor.

[0075] 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.

[0076] Such asFigure 2 As shown, the present application also provides a sampling time diagram of voltage vectors. In the diagram is represented as the zero voltage vector, is represented as the first effective voltage vector, is represented as the second effective voltage vector, , is represented as 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 . During a 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 a PWM period, in any sector, when the same voltage vector acts, the voltage on the axis is a constant; when different voltage vectors act, the voltage values on the axis are not equal.

[0077] It should be noted that the present 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.

[0078] The present application also provides a table of voltage values of a permanent magnet synchronous motor when different sectors and different voltage vectors act.

[0079]

[0080] 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 represents that the upper arm of the phase of the three-phase bridge arm is turned on and the lower arm is turned off, =1 represents that the upper arm of the phase of the three-phase bridge arm is turned on and the lower arm is turned off, =1 represents that the upper arm of the phase of the three-phase bridge arm is turned on and the lower arm is turned off, =0 represents that the The lower bridge arm of the phase is turned on and the upper bridge arm is turned off, = 0 represents a three-phase bridge arm The lower bridge arm of the phase is turned on and the upper bridge arm is turned off, = 0 represents a three-phase bridge arm The lower bridge arm of the phase 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 axis, Is represented as The voltage of the axis, Z0 is represented as the zero voltage vector, and Z7 is represented as the zero voltage vector.

[0081] S12, based on 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, and the coordinate transformation, calculate the sine and cosine values of the double electrical angle, the intermediate inductance variable value and the initial value of the stator resistance of the permanent magnet synchronous motor when the zero voltage vector acts; 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.

[0082] Through the above settings, in 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 the online identification method for identifying the inductance of the permanent magnet synchronous motor.

[0083] In this application, based on the mathematical relationship between the electrical variables under the action of the first effective voltage vector and the second voltage vector and the parameters of the permanent magnet synchronous motor, and the coordinate transformation, the 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 are calculated.

[0084] S13, select the mathematical relationship between the relevant variables under the action of the zero voltage vector, the parameters of the permanent magnet synchronous motor and the electrical angle, and 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.

[0085] 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.

[0086] Meanwhile, the positive and cosine estimated values of the electrical angle are obtained by calculation to determine the polarities of the positive and cosine values of the electrical angle, so as to improve the accuracy of obtaining the electrical angle of the permanent magnet synchronous motor subsequently, which is beneficial to improving the accuracy of identifying the parameters of the permanent magnet synchronous motor by the subsequent online identification method.

[0087] In this application, the voltage equation of the permanent magnet synchronous motor under the action of the zero voltage vector is used 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 the zero voltage vector. Therefore, the 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, the absolute values of the sine and cosine of the electrical angle under the action of the zero voltage vector are calculated through the second model.

[0088] 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 sine and cosine values of the electrical angle of the permanent magnet synchronous motor when the zero voltage vector acts.

[0089] Generally, the electrical angle of the existing permanent magnet synchronous motor is 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 during the operation of the permanent magnet synchronous motor, there are errors in the electrical angle of the permanent magnet synchronous motor detected by the sensor.

[0090] Through the above settings, the electrical angle of the permanent magnet synchronous motor is obtained by calculation, which 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 beneficial to improving the accuracy of identifying the parameters of the permanent magnet synchronous motor by the subsequent online identification method of the permanent magnet synchronous motor parameters.

[0091] Meanwhile, the accurate sine and cosine values of the electrical angle are calculated 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 uncertainty of the electrical angle in terms of numerical value and polarity. Therefore, the accurate value of the electrical angle of the permanent magnet synchronous motor can be obtained, further improving the accuracy of calculating the final value of the resistance and the final value of the magnetic chain of the permanent magnet synchronous motor by the subsequent online identification method, which is beneficial to improving the accuracy of identifying the parameters of the permanent magnet synchronous motor by the online identification parameters.

[0092] S15. Based on the mathematical relationship between the relevant variables, the parameters of the permanent magnet synchronous motor and the electrical angle when the zero voltage vector of the permanent magnet synchronous motor acts, as well as the accurate sine and cosine values of the electrical angle and multiple parameter matrices when the zero voltage vector acts, calculate the final value of the resistance and the final value of the magnetic chain of the permanent magnet synchronous motor.

[0093] With the above settings, after determining the accurate value of the electrical angle, substitute the accurate values of the voltage, current, current differential, electrical angular velocity, and 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 accurate final magnetic flux linkage value of the permanent magnet synchronous motor can be directly calculated and obtained, thereby improving the accuracy of the online identification method for identifying the resistance value and magnetic flux linkage value of the permanent magnet synchronous motor.

[0094] In this application, a third model is established 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, as well as the accurate sine and cosine values of the electrical angle and multiple parameter matrices when under the action of the zero voltage vector, that is, the third model is used to calculate the accurate final resistance value and the accurate final magnetic flux linkage value of the permanent magnet synchronous motor. By using the third model to calculate the accurate final resistance value and the accurate final magnetic flux linkage value of the permanent magnet synchronous motor, the accurate final resistance value and the accurate final magnetic flux linkage value of the permanent magnet synchronous motor can be accurately obtained, thereby improving the accuracy of the online identification method for identifying the parameters of the permanent magnet synchronous motor.

[0095] 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.

[0096] As an implementation method, obtain the relevant variables of the permanent magnet synchronous motor under the action of multiple voltage vectors, and establish the following expression for the mathematical relationship between the relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of multiple voltage vectors:

[0097] (Formula 1);

[0098] (Formula 2);

[0099] (Formula 3);

[0100] Wherein, is expressed as the axis voltage of the permanent magnet synchronous motor, is expressed as the axis voltage of the permanent magnet synchronous motor, is expressed as the axis current of the permanent magnet synchronous motor, is expressed as the axis current of the permanent magnet synchronous motor, is expressed as the current differential of the is expressed as the current differential of the is expressed as the electrical angular velocity of the permanent magnet synchronous motor, is expressed as the unknown quantity of the electrical angle of the permanent magnet synchronous motor, is represented as the parameter matrix of the permanent magnet synchronous motor, is represented as the parameter matrix of the permanent magnet motor, is represented as the zero voltage vector, is represented as the first effective voltage vector, is represented as the second effective voltage vector, is represented as the stator resistance value, is represented as the flux linkage value.

[0101] Through the above settings, within one PWM cycle, the permanent magnet synchronous motor under the action of the first effective voltage vector, the second effective voltage vector and the zero voltage vector is sampled, and the data during its operation is collected, including the voltage, current, current differential of the [[axis]], and the voltage, current, current differential and electrical angular velocity of the [[axis]] 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.

[0102] As an implementation, the parameter matrix and the parameter matrix are calculated through the following expressions:

[0103]

[0104] (Formula 4);

[0105] ;

[0106] (Formula 5);

[0107] wherein, is represented as the direct-axis inductance value of the permanent magnet synchronous motor, is represented as the quadrature-axis inductance value of the permanent magnet synchronous motor.

[0108] As an implementation, based on the mathematical relationship between 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, and 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:

[0109] (Formula 6);

[0110] (Formula 7);

[0111] (Formula 8);

[0112] Among them, is expressed as a parameter related to voltage, current, current differential, and Park matrix, , ∈{1, 2, 3, 4}, is expressed as the electrical angle of the permanent magnet motor under the action of the zero voltage vector; is expressed as the sine value of twice the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector, is expressed as the cosine value of twice the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector, is expressed as 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:

[0113]

[0114] (Formula 9);

[0115] ;

[0116] (Formula 10);

[0117] ;

[0118] (Formula 11).

[0119] 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 parameter identification model of the permanent magnet synchronous motor is established based on the voltage equation, that is, the first model is established through Formula 6 to calculate accurate inductance values, absolute values of sine and cosine, and multiple parameter matrices, so as to improve the accuracy of subsequent parameter identification of the permanent magnet synchronous motor.

[0120] As an implementation manner, based on the mathematical relationship between the Park matrix and the relevant variables under the action of multiple voltage vectors, the permanent magnet synchronous motor parameters, 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 parameters , and the expression of the intermediate voltage equation is as follows:

[0121] (Formula 12);

[0122] (Equation 13);

[0123] 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, ; Replace the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with the parameters The expressions are as follows:

[0124] (Equation 14);

[0125] (Equation 15).

[0126] Exemplarily, in the present application, the calculation process of the common parameter is as follows:

[0127] 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, obtaining the first voltage vector equation set, and its specific expressions are as follows:

[0128] (Equation 16);

[0129] (Equation 17);

[0130] Then, multiply the left side of the voltage vector equation under the action of the first effective voltage vector in the first voltage vector equation set by , and multiply the left side of the voltage vector equation under the action of the second effective voltage vector in the first voltage vector equation set by , obtaining the following expression of the second voltage vector equation set:

[0131] (Equation 18);

[0132] (Equation 19).

[0133] 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 action of the zero voltage vector in S11 from the second voltage vector equation set, the expression of the intermediate voltage equation can be obtained:

[0134] (Equation 20);

[0135] (Equation 21).

[0136] 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:

[0137] (Equation 22);

[0138] (Equation 23);

[0139] Finally, sample the permanent magnet synchronous motor under the action of different voltage vectors within a PWM period 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 process of calculating the common parameters , voltage, current, current differential, and electrical angular velocity are all parameters obtained by sampling the permanent magnet synchronous motor, so that additional excitation signals or initial parameters can be avoided, thereby improving the accuracy of the parameters and facilitating the improvement of the accuracy of online identification of permanent magnet synchronous motor parameters.

[0140] As an implementation, when substituting 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:

[0141]

[0142] (Equation 24);

[0143] where .

[0144] As an implementation, based on the mathematical relationship 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, as well as the initial value of the resistance , the parameter matrix and the parameter matrix , the expression for calculating the estimated values of the sine and cosine values of the electrical angle of the permanent magnet synchronous motor is as follows:

[0145] (Formula 25);

[0146] (Formula 26);

[0147] ;

[0148] (Formula 27);

[0149] 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.

[0150] Through the above settings, the initial value of the magnetic flux and the voltage, current, current differential and electrical angular velocity of the permanent magnet synchronous motor under the action of the zero voltage vector are substituted into formula 25, and the estimated value of the sine and cosine value of the electrical angle can be calculated. Therefore, the polarity of the electrical angle of the permanent magnet synchronous motor can be accurately judged with the help of the estimated value of the sine and cosine value of the electrical angle, so as to improve the accuracy of the subsequently obtained electrical angle, and then improve the accuracy of the online identification of the permanent magnet synchronous motor parameters.

[0151] In the present application, a corresponding voltage equation is established based on the voltage, current, current differential and electrical angular velocity of the permanent magnet synchronous motor, and then a second parameter identification model of the permanent magnet synchronous motor is established based on the voltage equation. That is, the accurate estimate of the sine and cosine values ​​of the electrical angle can be calculated by formula 25, so as to improve the accuracy of subsequent permanent magnet synchronous motor parameter identification.

[0152] As an implementation method, 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 value of the electrical angle under the action of the zero voltage vector, the expression for calculating the exact value of the sine and cosine of the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector is as follows:

[0153] ; (Formula 28);

[0154] in, Expressed as the exact value of the electrical angle sine, Expressed as the exact value of the electrical angle cosine.

[0155] Through the above settings, the absolute value of the sine and cosine of the electrical angle and the polarity 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 equation is selected according to the polarity of the sine and cosine values ​​of the electrical angle, so as to obtain the sine function and cosine function of the accurate value of the electrical angle, so as to obtain the accurate value of the electrical angle, thereby improving the accuracy of the calculated accurate value of the electrical angle, so as to improve the accuracy of the online identification method of the permanent magnet synchronous motor parameters.

[0156] As an implementation manner, based on the mathematical relationships among relevant variables, permanent magnet synchronous motor parameters, and electrical angle under the action of zero voltage vectors, as well as the exact values of the sine and cosine of the electrical angle and 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:

[0157] (Equation 29);

[0158] wherein, is expressed as the final resistance value, is expressed as the final flux linkage value.

[0159] Through the above settings, after determining the exact value of the electrical angle, substitute the voltage, current, and current differential under the action of the zero voltage vector to construct the corresponding equation, so that the accurate final resistance value and the final flux linkage value can be obtained, which is beneficial to improving the accuracy of the online identification method of permanent magnet synchronous motor parameters.

[0160] 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 third parameter identification model of the permanent magnet synchronous motor is established based on the voltage equation. The accurate final resistance value and the final flux linkage value can be calculated through Equation 29, which is beneficial to improving the accuracy of the permanent magnet synchronous motor parameter identification.

[0161] As Figure 3 shown, this application also provides an online identification system for permanent magnet synchronous motor parameters, and this online identification system can execute the online identification method of permanent magnet synchronous motor parameters.

[0162] Through the above settings, a sufficient number of voltage equations regarding the action of different voltage vectors can be constructed to represent the mathematical relationships among the relevant variables, permanent magnet synchronous motor parameters, and electrical angle of the permanent magnet synchronous motor under the action of different voltage vectors, so that the problem of under-rank can be avoided when identifying the parameters of multiple permanent magnet synchronous motors.

[0163] Meanwhile, 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 permanent magnet synchronous motor parameter identification, which is beneficial to improving the accuracy of the online identification system for identifying the permanent magnet synchronous motor parameters.

[0164] 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 the electrical angle can be avoided from being input, so as to avoid the influence of the electrical angle error on the permanent magnet synchronous motor parameter identification, and further improve the accuracy of the online identification system for identifying the permanent magnet synchronous motor parameters.

[0165] 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, thereby avoiding the interference of the additional excitation signal on the operating state of the permanent magnet synchronous motor, and further improving the stability of the permanent magnet synchronous motor during operation.

[0166] 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 a 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.

[0167] 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, thereby realizing the online accurate identification of all electrical parameters, and further improving the performance of the permanent magnet synchronous motor control algorithm.

[0168] 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 should fall within the protection scope of the appended claims of this application.

Claims

1. An online identification method for the parameters of a permanent magnet synchronous motor, characterized in that, The online identification method includes: Obtaining relevant variables of a permanent magnet synchronous motor under the action of multiple voltage vectors, where 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 under the action of the multiple voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle; Based on the mathematical relationship between the relevant variables under the action of the multiple voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle, and coordinate transformation, calculating the sine and cosine values of twice the 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; calculating the absolute values of the sine and cosine of the electrical angle, the inductance value, and multiple parameter matrices, where the inductance value includes the quadrature-axis inductance value and the direct-axis inductance value; Selecting the mathematical relationship between the relevant variables under the action of the zero voltage vector, the parameters of the permanent magnet synchronous motor, and the electrical angle, and the initial value of the stator resistance and multiple parameter matrices, calculating 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 determining 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, determining 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 of the permanent magnet synchronous motor under the action of the zero voltage vector, the parameters of the permanent magnet synchronous motor, and the electrical angle, and the accurate sine and cosine values of the electrical angle and multiple parameter matrices when under the action of the zero voltage vector, calculating the final resistance value and the final flux linkage value of the permanent magnet synchronous motor; 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 the multiple voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle is as follows: ； ； ； Among them, denoted as the shaft voltage of the permanent magnet synchronous motor, denoted as the shaft voltage of the permanent magnet synchronous motor, denoted as the shaft current, denoted as the shaft current of the permanent magnet synchronous motor, denoted as the current differential of the shaft, denoted as the current differential of the shaft, denoted as the electrical angular velocity of the permanent magnet synchronous motor, denoted as the unknown quantity of the electrical angle of the permanent magnet synchronous motor, denoted as the parameter matrix of the permanent magnet synchronous motor, denoted as the parameter matrix of the permanent magnet motor, denoted as the zero voltage vector, denoted as the first effective voltage vector, denoted as the second effective voltage vector, denoted as the stator resistance value, denoted as the flux linkage value; The parameter matrix and the parameter matrix are calculated by the following expressions: ； ； ； ； Among them, represents the direct-axis inductance value of the permanent magnet synchronous motor, represents the quadrature-axis inductance value of the permanent magnet synchronous motor.

2. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 1, characterized in that Based on the mathematical relationships among 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, obtain the intermediate voltage equation, and replace the quantities related to voltage, current, current differential, and the Park matrix in the intermediate voltage equation with parameters , the expressions for calculating 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 under the action of the zero voltage vector are as follows: ； ； ； ； Among them, is expressed as a parameter related to voltage, current, current differential, and Park matrix, , ∈{1, 2, 3, 4}, is expressed as the electrical angle of the permanent magnet motor under the action of the zero voltage vector; is expressed as the sine value of twice the electrical angle of the permanent magnet synchronous motor under the action of the zero voltage vector, is expressed as the cosine value of twice the electrical angle of the permanent magnet synchronous motor 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 calculated electrical angle, the direct-axis inductance value and the quadrature-axis inductance value , the parameter matrix and the parameter matrix are expressed as follows: ； ； ； ； ； 。 3. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 2, characterized in that Based on the mathematical relationships among relevant variables under the Park matrix and 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 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: ； ； Among them, 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, ; replace the quantities related to voltage, current, current differential, and Park matrix in the intermediate voltage equation with the parameters The expression is as follows: 。 4. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 2, characterized in that Replacing the quantities related to voltage, current, current differential, and the Park matrix in the intermediate voltage equation with parameters when, the expression of the Park matrix is as follows: ； ； Among them, .

5. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 1, characterized in that The mathematical relationships among the relevant variables of the permanent magnet synchronous motor under the action of the zero voltage vector, the parameters of the permanent magnet synchronous motor, and the electrical angle, as well as the initial value of the resistance , the parameter matrix and the parameter matrix , the expression for calculating the estimated values of the sine and cosine of the electrical angle of the permanent magnet synchronous motor is 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.

6. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 1, characterized in that, The expression 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 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 is as follows: ； ； wherein, represents the accurate value of the sine of the electrical angle, represents the accurate value of the cosine of the electrical angle.

7. The online identification method for the parameters of a permanent magnet synchronous motor according to claim 1, characterized in that Based on the mathematical relationships among relevant variables under the action of zero voltage vectors, the parameters of the permanent magnet synchronous motor, and the electrical angle, as well as the accurate sine and cosine values of the electrical angle and 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: ； Among them, is expressed as the final value of the resistance, is expressed as the final value of the magnetic flux linkage.

8. An online identification system for parameters of a permanent magnet synchronous motor, characterized in that The online identification system can execute the online identification method for parameters of a permanent magnet synchronous motor as described in any one of claims 1 to 7.

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