A method for calibrating permanent magnet synchronous motor in all operating ranges

Abstract

The present invention discloses a method for calibrating a permanent magnet synchronous motor in the full operating condition area, comprising the following steps: S1, obtaining motor parameters; S2, selecting calibration feature points covering the boundary state of the motor working area, and determining the current vector is and the current vector phase angle θ corresponding to each group of the calibration torque; S3, respectively obtaining a calibration torque-current vector is curve diagram and a calibration torque-current vector phase angle θ curve diagram under each of the calibration voltages and each of the calibration speed conditions; S4, obtaining the current vector is and the current vector phase angle θ corresponding to the current torque requested in the full operating condition area of ​​the motor operation; the present invention completes the motor calibration without the need for the motor party to provide accurate motor design parameters and simulation data, improves the control accuracy, does not cause the torque to lose control, avoids repeated calibration, and calibrates the motor once and continuously uses the motor throughout its life cycle.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet synchronous motor calibration, and in particular to a method for calibrating a permanent magnet synchronous motor in the full operating range. Background Art

[0002] The permanent magnet synchronous motor used in electric vehicles needs to be matched and tested with the corresponding motor controller before use. This process is usually called motor calibration, which is generally performed on a motor test bench. During the use of the electric vehicle drive motor, the driver steps on the accelerator pedal and issues a torque command, that is, a vehicle driving force command. After the command is issued by the accelerator pedal, it is output to the motor controller via the vehicle controller. The motor controller converts the command into a motor current signal and controls the drive motor to execute the torque. Therefore, the motor calibration process is actually the process in which the motor controller converts the torque command into a motor current signal to form a current control table. In order to improve the comfort and stability of electric vehicles, the deviation between the actual output torque of the motor and the torque command is required to be within a certain range, generally within ±5Nm (when the torque command is within ±100Nm) or ±5% (when the torque command is above ±100Nm). Therefore, the motor calibration process requires that the current command in the generated current table is very accurate.

[0003] In the existing motor control algorithm, the three-phase current (ABC phase) of the three-phase AC motor is generally converted into two-phase AC and DC currents (d-axis current Id, q-axis current Iq) related to the motor rotor position using dq transformation. Therefore, the motor current control signal is generally in the form of Id and Iq in the motor controller. When the motor is at different speeds and different torque commands, the motor controller outputs different Id and Iq commands to the drive motor to achieve torque output.

[0004] Before installing and debugging the permanent magnet synchronous motor, it is necessary to use a bench to perform a calibrated torque test through the motor controller. The result of the bench test directly determines the performance of the permanent magnet synchronous motor on the vehicle. There are many methods for motor calibration. Through research, the existing motor calibration technology roughly has the following methods:

[0005] 1. Build a motor simulation model, generate calibration data through the model, verify the torque characteristics on the test bench, and correct the simulation data based on the test bench verification results;

[0006] 2. The motor torque control algorithm adopts a multi-closed loop (torque closed loop, weak magnetic closed loop, current closed loop) method, which is independent of motor parameters and torque data for adjustment through closed loop control;

[0007] 3. Calibrate the torque control data at rated voltage. For other voltages, control is performed using the voltage vector limiting algorithm.

[0008] The defect of the first method mentioned above is that building a motor simulation model requires familiarity with the motor model. Often during the development process, the motor and the motor controller are developed by two parties, and technical integration cannot be achieved. At the same time, the construction of the simulation software platform involves software tool development and personnel maintenance, which invisibly increases the cost of motor calibration. After the simulation data is generated, the bench test results are still the main focus, and the simulation data is only an auxiliary testing method.

[0009] The drawback of the second method is that the torque control accuracy and torque control response are poor. When special working conditions such as fast torque response are required, there is a risk of current runaway. It is not suitable for electric vehicles with high torque accuracy and high response.

[0010] The drawback of the third method is that, under non-rated voltage conditions, especially when the voltage is lower than the rated voltage, the torque accuracy cannot be guaranteed, and it is not suitable for electric vehicles with high torque accuracy requirements. Summary of the invention

[0011] The purpose of the present invention is to provide a method for calibrating a permanent magnet synchronous motor in the full operating range in order to solve the problems existing in the prior art. The method can complete the motor calibration without requiring the motor party to provide accurate motor design parameters and simulation data, thereby improving the control accuracy and avoiding repeated calibration.

[0012] To achieve the above object, the technical solution adopted by the present invention is:

[0013] A method for calibrating a permanent magnet synchronous motor in the full operating range is as follows:

[0014] S1. Obtain motor parameters, and convert motor line resistance r, motor flux ψ f , the d-axis inductance curve and the q-axis inductance curve are written into the feed-forward voltage equation;

[0015] S2, select the calibration feature points covering the boundary state of the motor working area, the calibration feature points include calibration voltage, calibration speed and calibration torque; determine the current vector i corresponding to each group of the calibration torque s and the current vector phase angle θ;

[0016] S3, respectively obtain the calibrated torque-current vector i under each of the calibrated voltages and each of the calibrated speeds s curve diagram and calibrated torque-current vector phase angle θ curve diagram;

[0017] S4, according to the target torque, motor speed and motor bus voltage of the current working condition, three dichotomy calculations are performed respectively to obtain the current vector i corresponding to the current torque requested in the full working condition area of ​​the motor operation sThe current vector phase angle θ is used to obtain the current commands of the d-axis and q-axis, which are passed into the motor control current loop and voltage feedforward term to achieve the target torque through drive control.

[0018] Furthermore, in step S1, the specific process of obtaining various parameters of the motor is as follows:

[0019] In order to ensure that the voltage vector u s and the current vector i s Under the premise of accurate phase, the motor line resistance r is directly measured by the resistance tester;

[0020] According to formula (1), three different features i are selected d value, get i d -L q The curve of

[0021] According to formula (2), three different features i are selected q value, get i q -L q The curve of

[0022] Permanent magnet synchronous motor voltage equation formula,

[0023] U d =i d r+pi d L d -ωi q L q

[0024] U q =i q r+pi q L q +ωi d L d +ωψ f (6);

[0025] Among them, u d is the d-axis voltage in the synchronous motor model, u q is the q-axis voltage in the synchronous motor model, i d is the d-axis current in the synchronous motor model, i q is the q-axis current in the synchronous motor model, r is the synchronous motor line resistance, p is the differential operator, L d is the d-axis inductance of the synchronous motor, L q is the q-axis inductance of the synchronous motor, ω is the electrical angle speed of the motor, ψ f is the magnetic flux of synchronous motor.

[0026] The test speed is selected as 2000rpm, ω=2000*N*2π / 60, and i is selected d and i qFeature point: i d =0,i q =i qmax ;i d =0,i q =i qmax / 2;i d =0,i q =i qmax / 10.

[0027] According to formula (6), in steady state, the differential operator term is neglected, and we get

[0028] The calculation formula of the d-axis inductance of the synchronous motor is: According to the selection of three different features i q value, and get i q -L q The curve of the non-feature point L q by i q Calculated by dichotomy.

[0029] Select i d and i q Feature point: i d =i dmax ,i q =0;i d =i dmax / 2,i q =0;i d =i dmax / 10,i q = 0. According to formula (6), in steady state, the differential operator term is negligible, and we get

[0030] The calculation formula of the q-axis inductance of the synchronous motor is: According to the selection of three different features i d value, and get i d -L d The curve of the non-feature point L d by i d Calculated by dichotomy.

[0031] The formula for calculating the magnetic flux of a synchronous motor is:

[0032]

[0033] Among them, u 反线rms is the effective value of the no-load back-EMF line voltage, n is the speed of the synchronous motor, and p is the number of synchronous motor pole pairs;

[0034] The u is measured by an oscilloscope. 反线rms , will u 反线rms Substituting into formula (3) we can get the motor flux ψ f .

[0035] The advantage of the above solution is that the motor parameters can be accurately identified offline without the need for the motor designer to provide relevant parameters.

[0036] Furthermore, the principle for selecting calibration feature points is that the calibration feature points of the motor bus voltage respectively select the minimum operating voltage, the rated voltage and the maximum operating voltage, the motor speed is calibrated once every 1000 rpm, and the calibration interval of the motor torque is 10 equal parts of the external characteristic torque of the motor at the current speed.

[0037] During the calibration process of step 2, the modulation coefficient λ is introduced in the calibration process for the controller output voltage saturation region. The calculation formula of the modulation coefficient λ is:

[0038]

[0039]

[0040] u s-max =0.816*0.707u dc ≈0.577u dc

[0041]

[0042] Among them, u s is the space voltage vector, u 相峰 is the phase voltage peak value, u 线rms is the effective value of line voltage, u 线rms-max is the maximum effective value of the line voltage, u s-max is the maximum value of the space vector voltage, and λ is the modulation coefficient.

[0043] In order to observe the stable modulation coefficient more intuitively during the calibration process, specific filtering is required, and the filtering adopts the first-order low-pass filtering. The software filtering algorithm is as follows:

[0044]

[0045] The execution frequency in the software where the algorithm is located is the first-order low-pass filter cutoff frequency. The appropriate filter cutoff frequency can be selected according to the actual debugging waveform, and the appropriate n value is matched in the software. In this invention, the filter cutoff frequency for the key quantity of the control system is set to 2Hz.

[0046] When the modulation coefficient λ is less than 1, the calibration process enters the non-voltage saturation region. First, it is set at the rated voltage and the current vector i is adjusted. s , the current vector phase angle θ, load the bench measured torque to the vicinity of the required calibration torque, and fix i s, fine-tune the current vector phase angle θ, and scan to the maximum torque-current ratio i s The combination of and θ is the i corresponding to the calibrated torque. s and θ, according to this calibration principle, the i corresponding to other calibrated speed and calibrated torque conditions s The combination of θ and θ is determined, and the minimum and maximum operating voltages are calibrated in the same way. It should be noted that in the non-voltage saturation region, the maximum operating voltage i s The combination with θ can reuse the rated voltage data, and only requires additional calibration of the area where the modulation coefficient λ is less than 1.

[0047] When the modulation coefficient λ reaches 1, the voltage saturation region calibration process begins. First, it is set at the rated voltage and then adjusted by i s is the current vector, θ is the current vector phase angle, and the adjustment coefficient is always stable at about 1. The actual torque measured on the bench is loaded to the vicinity of the required calibration torque, and the current vector phase angle θ is fine-tuned to scan to the maximum torque-current ratio i s The combination of and θ is the i corresponding to the calibrated torque. s and θ, according to this calibration principle, the i corresponding to other calibrated speed and calibrated torque conditions s After the combination of θ and θ is determined, the minimum operating voltage and the maximum operating voltage are calibrated in the same way.

[0048] The above calibration method does not require investment in electronic control simulation design and purchase of related development tools, thus achieving motor calibration and reducing development and testing costs.

[0049] Through the above voltage saturation region and non-voltage saturation region calibration method, the torque at the calibration speed point under the minimum working voltage, rated voltage and maximum working voltage can be obtained respectively. s curve and torque-θ curve, fit the calibration data to the two-dimensional array curve respectively, and finally obtain the current vector i corresponding to the target torque s , the current vector phase angle θ, the d and q axis current commands are obtained through formula (5), which are input into the motor control current loop and voltage feedforward term, and finally the target torque is achieved through drive control. The above method improves the stability and reliability of torque control and avoids repeated bench calibration verification. Once the motor is calibrated, it can be continuously used throughout its life cycle.

[0050] Among them, the current command formula of the d-axis and q-axis is:

[0051] i dref =i s *cosθ

[0052] i qref =i s *sinθ (5);

[0053] Among them, i s is the current vector, θ is the current vector phase angle, i dref and i qref They are the d-axis current command and the q-axis current command respectively.

[0054] The above torque realization accuracy reaches ±1% in the entire operating range of the motor, and the torque response time from zero loading to the motor peak torque is within 100ms.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. Accurately identify motor parameters offline without the need for motor designers to provide relevant parameters;

[0057] 2. The torque controller accuracy reaches ±1% in the full range of motor operation, and the torque response time from zero loading to motor peak torque is within 100ms;

[0058] 3. No need to invest in electronic control simulation design and purchase related development tools, motor calibration can be achieved, reducing development and testing costs;

[0059] 4. Improve the stability and reliability of torque control, avoid repeated bench calibration and verification, and calibrate the motor once, and the motor will continue to benefit throughout its life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a block diagram of the motor vector control of the present invention; DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] In the description of the present invention, it should be noted that the terms "up", "down", "left", "right", "top", "bottom", "inside", "outside", "horizontal", "vertical", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0063] A method for calibrating a permanent magnet synchronous motor in the full operating range is as follows:

[0064] S1. Obtain motor parameters, and convert motor line resistance r, motor flux ψf , the d-axis inductance curve and the q-axis inductance curve are written into the feed-forward voltage equation;

[0065] S2, select the calibration feature points covering the boundary state of the motor working area, the calibration feature points include calibration voltage, calibration speed and calibration torque; determine the current vector i corresponding to each group of the calibration torque s and the current vector phase angle θ;

[0066] S3, respectively obtain the calibrated torque-current vector i under each of the calibrated voltages and each of the calibrated speeds s curve diagram and calibrated torque-current vector phase angle θ curve diagram;

[0067] S4, according to the target torque, motor speed and motor bus voltage of the current working condition, three dichotomy calculations are performed respectively to obtain the current vector i corresponding to the current torque requested in the full working condition area of ​​the motor operation s The current vector phase angle θ is used to obtain the current commands of the d-axis and q-axis, which are passed into the motor control current loop and voltage feedforward term to achieve the target torque through drive control.

[0068] Furthermore, in step S1, the specific process of obtaining various parameters of the motor is as follows:

[0069] In order to ensure that the voltage vector u s and the current vector i s Under the premise of accurate phase, the motor line resistance r is directly measured by the resistance tester;

[0070] According to formula (1), three different features i are selected d value, get i d -L q The curve of

[0071] According to formula (2), three different features i are selected q value, get i q -L q The curve of

[0072] Permanent magnet synchronous motor voltage equation formula,

[0073] U d =i d r+pi d L d -ωi q L q

[0074] U q =i q r+pi q L q +ωi d Ld +ωψ f (6);

[0075] Among them, u d is the d-axis voltage in the synchronous motor model, u q is the q-axis voltage in the synchronous motor model, i d is the d-axis current in the synchronous motor model, i q is the q-axis current in the synchronous motor model, r is the synchronous motor line resistance, p is the differential operator, L d is the d-axis inductance of the synchronous motor, L q is the q-axis inductance of the synchronous motor, ω is the electrical angle speed of the motor, ψ f is the magnetic flux of synchronous motor.

[0076] The test speed is selected as 2000rpm, ω=2000*N*2π / 60, and i is selected d and i q Feature point: i d =0,i q =i qmax ;i d =0,i q =i qmax / 2;i d =0,i q =i qmax / 10.

[0077] According to formula (6), in steady state, the differential operator term is neglected, and we get

[0078] The calculation formula of the d-axis inductance of the synchronous motor is: According to the selection of three different features i q value, and get i q -L q The curve of the non-feature point L q by i q Calculated by dichotomy.

[0079] Select i d and i q Feature point: i d =i dmax ,i q =0;i d =i dmax / 2,i q =0;i d =i dmax / 10,i q = 0. According to formula (6), in steady state, the differential operator term is negligible, and we get

[0080] The calculation formula of the q-axis inductance of the synchronous motor is: According to the selection of three different features i d value, and get i d -L d The curve of the non-feature point L d byi d Calculated by dichotomy.

[0081] The formula for calculating the magnetic flux of a synchronous motor is:

[0082]

[0083] Among them, u 反线rms is the effective value of the no-load back-EMF line voltage, n is the speed of the synchronous motor, and p is the number of synchronous motor pole pairs;

[0084] The u is measured by an oscilloscope. 反线rms , will u 反线rms Substituting into formula (3) we can get the motor flux ψ f .

[0085] The advantage of the above solution is that the motor parameters can be accurately identified offline without the need for the motor designer to provide relevant parameters.

[0086] Furthermore, the principle for selecting calibration feature points is that the calibration feature points of the motor bus voltage respectively select the minimum operating voltage, the rated voltage and the maximum operating voltage, the motor speed is calibrated once every 1000 rpm, and the calibration interval of the motor torque is 10 equal parts of the external characteristic torque of the motor at the current speed.

[0087] During the calibration process of step 2, the modulation coefficient λ is introduced in the calibration process for the controller output voltage saturation region. The calculation formula of the modulation coefficient λ is:

[0088]

[0089] Among them, u s is the space voltage vector, u 相峰 is the phase voltage peak value, u 线rms is the effective value of line voltage, u 线rms-max is the maximum effective value of the line voltage, u s-max is the maximum value of the space vector voltage, and λ is the modulation coefficient.

[0090] In order to observe the stable modulation coefficient more intuitively during the calibration process, specific filtering is required, and the filtering adopts the first-order low-pass filtering. The software filtering algorithm is as follows:

[0091]

[0092] The execution frequency in the software where the algorithm is located is the first-order low-pass filter cutoff frequency. The appropriate filter cutoff frequency can be selected according to the actual debugging waveform, and the appropriate n value is matched in the software. In this invention, the filter cutoff frequency for the key quantity of the control system is set to 2Hz.

[0093] When the modulation coefficient λ is less than 1, the calibration process enters the non-voltage saturation region. First, it is set at the rated voltage and the current vector i is adjusted. s , the current vector phase angle θ, load the bench measured torque to the vicinity of the required calibration torque, and fix i s , fine-tune the current vector phase angle θ, and scan to the maximum torque-current ratio i s The combination of and θ is the i corresponding to the calibrated torque. s and θ, according to this calibration principle, the i corresponding to other calibrated speed and calibrated torque conditions s The combination of θ and θ is determined, and the minimum and maximum operating voltages are calibrated in the same way. It should be noted that in the non-voltage saturation region, the maximum operating voltage i s The combination with θ can reuse the rated voltage data, and only requires additional calibration of the area where the modulation coefficient λ is less than 1.

[0094] When the modulation coefficient λ reaches 1, the voltage saturation region calibration process begins. First, it is set at the rated voltage and then adjusted by i s is the current vector, θ is the current vector phase angle, and the adjustment coefficient is always stable at about 1. The actual torque measured on the bench is loaded to the vicinity of the required calibration torque, and the current vector phase angle θ is fine-tuned to scan to the maximum torque-current ratio i s The combination of and θ is the i corresponding to the calibrated torque. s and θ, according to this calibration principle, the i corresponding to other calibrated speed and calibrated torque conditions s After the combination of θ and θ is determined, the minimum operating voltage and the maximum operating voltage are calibrated in the same way.

[0095] The above calibration method does not require investment in electronic control simulation design and purchase of related development tools, thus achieving motor calibration and reducing development and testing costs.

[0096] Through the above voltage saturation region and non-voltage saturation region calibration method, the torque at the calibration speed point under the minimum working voltage, rated voltage and maximum working voltage can be obtained respectively. s curve and torque-θ curve, fit the calibration data to the two-dimensional array curve respectively, and finally obtain the current vector i corresponding to the target torque s, the current vector phase angle θ, the d and q axis current commands are obtained through formula (5), which are input into the motor control current loop and voltage feedforward term, and finally the target torque is achieved through drive control. The above method improves the stability and reliability of torque control and avoids repeated bench calibration verification. Once the motor is calibrated, it can be continuously used throughout its life cycle.

[0097] Among them, the current command formula of the d-axis and q-axis is:

[0098]

[0099] Among them, i s is the current vector, θ is the current vector phase angle, i dref and i qref They are the d-axis current command and the q-axis current command respectively.

[0100] The above torque realization accuracy reaches ±1% in the entire operating range of the motor, and the torque response time from zero loading to the motor peak torque is within 100ms.

[0101] A specific example of obtaining current instructions by binary division is as follows:

[0102] S01, obtaining command signals of bus voltage, motor speed and motor torque;

[0103] S02, querying calibration data under calibration voltage 1 and calibration voltage 2;

[0104] S03. Under the condition of calibration voltage 1, query the calibration data under calibration speed 1 and calibration speed 2;

[0105] Under the condition of calibration voltage 2, query the calibration data under calibration speed 3 and calibration speed 4;

[0106] S04. Under the condition of calibrated speed 1, query the i corresponding to calibrated torque 1 and calibrated torque 2 s and θ;

[0107] Under the condition of calibrated speed 2, query the i corresponding to calibrated torque 3 and calibrated torque 4 s and θ;

[0108] Under the condition of calibrated speed 3, query the i corresponding to calibrated torque 5 and calibrated torque 6 s and θ;

[0109] Under the condition of calibrated speed 4, query the i corresponding to calibrated torque 7 and calibrated torque 8 s and θ;

[0110] S05. According to the torque command, calibrate torque 1 and calibrate torque 2, and calculate the i corresponding to the current working condition according to the dichotomy method. s 1 and θ1;

[0111] According to the torque command, the calibrated torque 3 and the calibrated torque 4, the i corresponding to the current working condition is calculated by the dichotomy method. s 2 and θ2;

[0112] According to the torque command, the calibrated torque 5 and the calibrated torque 6, the i corresponding to the current working condition is calculated by the dichotomy method. s 3 and θ3;

[0113] According to the torque command, the calibrated torque 7 and the calibrated torque 8, the i corresponding to the current working condition is calculated by the dichotomy method. s 4 and θ4;

[0114] S06. According to the actual motor speed, the calibrated speed 1 and the calibrated speed 2, the i corresponding to the current working condition is calculated by the dichotomy method. s 5 and θ5;

[0115] According to the actual motor speed, the calibrated speed 3 and the calibrated speed 4, the i corresponding to the current working condition is calculated by the dichotomy method. s 6 and θ6.

[0116] S07, according to the actual bus voltage, calibration voltage 1 and calibration voltage 2, calculate the i corresponding to the current working condition according to the dichotomy method s and θ.

[0117] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calibrating a permanent magnet synchronous motor in the full operating range, characterized in that: The following steps are involved: S1. Obtain motor parameters, and convert motor line resistance r, motor flux ψ f , the d-axis inductance curve and the q-axis inductance curve are written into the feed-forward voltage equation; S2, select the calibration feature points covering the boundary state of the motor working area, the calibration feature points include calibration voltage, calibration speed and calibration torque; determine the current vector i corresponding to each group of the calibration torque s and the current vector phase angle θ; S3, respectively obtain the calibrated torque-current vector i under each of the calibrated voltages and each of the calibrated speeds s curve diagram and calibrated torque-current vector phase angle θ curve diagram; S4, according to the target torque, motor speed and motor bus voltage of the current working condition, three dichotomy calculations are performed respectively to obtain the current vector i corresponding to the current torque requested in the full working condition area of ​​the motor operation s The current vector phase angle θ is used to obtain the current commands of the d-axis and q-axis, which are input into the motor control current loop and voltage feedforward term to achieve the target torque through drive control. In order to ensure that the voltage vector u s and the current vector i s Under the premise of accurate phase, the motor line resistance r is directly measured by the resistance tester; The calculation formula of the d-axis inductance of the synchronous motor is: The calculation formula of the q-axis inductance of the synchronous motor is: Among them, u d is the d-axis voltage in the synchronous motor model, u q is the q-axis voltage in the synchronous motor model, i d is the d-axis current in the synchronous motor model, i q is the q-axis current in the synchronous motor model, L d is the d-axis inductance of the synchronous motor, L q is the q-axis inductance of the synchronous motor, ω is the electrical angle speed of the motor; According to formula (1), three different characteristic id values ​​are selected to obtain the id-Lq curve; According to formula (2), three different characteristic iq values ​​are selected to obtain the iq-Lq curve; The formula for calculating the magnetic flux of a synchronous motor is: Among them, u 反线rms is the effective value of the no-load back-EMF line voltage, n is the speed of the synchronous motor, and p is the number of synchronous motor pole pairs; The u is measured by an oscilloscope. 反线rms , will u 反线rms Substituting into formula (3) we can get the motor flux ψ f ; The calibration characteristic points of the motor bus voltage are respectively selected as the minimum working voltage, the rated voltage and the maximum working voltage, the motor speed is calibrated once every 1000rpm, and the calibration interval of the motor torque is 10 evenly selected at the current motor speed. In step 2, the current vector i corresponding to each set of calibrated torque is determined s The specific process of the current vector phase angle θ is as follows: first, the rated voltage is set, and then the current vector i is adjusted. s , the current vector phase angle θ, load the bench measured torque to the vicinity of the required calibration torque, and fix i s , fine-tune the current vector phase angle θ, and scan to the i when the torque current ratio is maximum s The combination of and θ is the i corresponding to the calibrated torque. s and θ, according to this calibration principle, the i corresponding to other calibrated speed and calibrated torque conditions s The combination of θ and θ is determined, and the minimum working voltage and the maximum working voltage are calibrated by the same method; For the controller output voltage saturation region, the modulation coefficient λ is introduced in the calibration process. The calculation formula of the modulation coefficient λ is: Among them, u s is the space voltage vector, u 相峰 is the phase voltage peak value, u 线rms is the effective value of line voltage, u 线rms-max is the maximum effective value of the line voltage, u s-max is the maximum value of the space vector voltage, λ is the modulation coefficient; When voltage saturation is reached, the modulation factor λ is maintained at 1 during the calibration process, and the optimal torque-current ratio data is selected; In order to observe the stable modulation coefficient more intuitively during the calibration process, specific filtering is required. The filtering adopts the first-order low-pass filtering. The software filtering algorithm is as follows: The execution frequency in the software where the algorithm is located is the first-order low-pass filter cutoff frequency. The appropriate filter cutoff frequency can be selected according to the actual debugging waveform.

2. A method for calibrating a permanent magnet synchronous motor in the full operating range according to claim 1, characterized in that: The current command formula for the d-axis and q-axis is: Among them, i s is the current vector, θ is the current vector phase angle, i dref and i qref They are d-axis current command and q-axis current command respectively; The current vector i corresponding to the target torque s Substituting the current vector phase angle θ into formula (5), the current instructions of the d-axis and q-axis are obtained.

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