Electromagnetic torque monitoring method, system and equipment and storage medium

Abstract

The invention discloses an electromagnetic torque monitoring method, system and device and a storage medium, and is applied to the technical field of electric drive system monitoring, and the method comprises the steps: collecting the three-phase current of a permanent magnet synchronous motor after the three-phase current sampling time of the permanent magnet synchronous motor is aligned with the equivalent angle time of a rotary transformer; determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected rotating speed, bus voltage and three-phase current of the permanent magnet synchronous motor; determining the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the acquired three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer and the cosine envelope signal output by the rotary transformer; and obtaining the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value and direction of the electromagnetic torque. By applying the scheme of the invention, the electromagnetic torque of the permanent magnet synchronous motor can be accurately determined, the implementation is simple and convenient, the consumed time is short, and the additional cost is not increased.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive system monitoring, and in particular to a method, system, device and storage medium for monitoring electromagnetic torque. Background Art

[0002] In recent years, people have paid more and more attention to the functional safety of new energy electric vehicles. The electric drive system is the core power component of electric vehicles, which can control the drive motor to generate the torque required for vehicle operation. Therefore, the increase or decrease of "unexpected torque" will pose a risk to the safe driving of the vehicle. In order to improve safety, it is necessary to monitor the torque of the electric drive system, that is, to estimate the electromagnetic torque of the motor in real time.

[0003] In the prior art, there are two commonly used methods for estimating the electromagnetic torque of a motor: the current method and the power method. The power method requires not only the acquisition of three-phase current, but also the acquisition of phase voltage / line voltage signals, which results in a relatively high hardware cost. In order to reduce system costs, some solutions will collect the IGBT (Insulated Gate Bipolar Transistor) state feedback pulse signal of the driver chip, and then use the IGBT state feedback pulse signal to reconstruct the phase voltage and thus realize power calculation. In this way, the support of the IGBT driver chip is first required. In addition, the reconstruction of the phase voltage will be affected by the motor PWM (Pulse Width Modulation) control frequency, so that the frequency conversion process and the overmodulation process need to be specially processed. At the same time, the phase relationship between the reconstructed phase voltage and the phase current needs to be considered, which makes the overall algorithm more complicated, the calibration process is also complicated, the estimation accuracy is not high, and the versatility is not high.

[0004] The current method is relatively simple, but it has high requirements for the decoding angle of the resolver, which makes it time-consuming and requires more computing resources.

[0005] In addition, when the system needs to achieve a higher safety level, the conventional approach is to use a combination of the current method and the power method to achieve redundancy in the monitoring method. In this way, the estimation of electromagnetic torque is restricted by the two algorithms, which not only makes the system complex and the hardware cost high, but also increases the difficulty of software implementation.

[0006] In summary, how to conveniently and effectively realize the monitoring of electromagnetic torque and ensure the accuracy of the monitored electromagnetic torque is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] The object of the present invention is to provide a method, system, device and storage medium for monitoring electromagnetic torque, so as to conveniently and effectively realize the monitoring of electromagnetic torque and ensure the accuracy of the monitored electromagnetic torque.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A method for monitoring electromagnetic torque, comprising:

[0010] After aligning the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer, collecting the three-phase current of the permanent magnet synchronous motor;

[0011] Determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current;

[0012] Determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer;

[0013] Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, the electromagnetic torque of the permanent magnet synchronous motor is obtained.

[0014] In one implementation, determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the acquired rotation speed, bus voltage, and three-phase current of the permanent magnet synchronous motor includes:

[0015] Based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table.

[0016] In one embodiment, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including:

[0017] Determining the sum of squares of three-phase currents of the permanent magnet synchronous motor;

[0018] Determining whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage;

[0019] If yes, then according to a pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0020] If no, follow The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the first table, based on the corrected speed and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0021] Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction;

[0022] The first table is a comparison table established in advance through bench calibration and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

[0023] In one embodiment, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including:

[0024] Determine the amplitude of the three-phase current of the permanent magnet synchronous motor; wherein the amplitude of the three-phase current of the permanent magnet synchronous motor I a , I b and I c The collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively;

[0025] Determining whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage;

[0026] If yes, then according to a pre-established second table, based on the rotation speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, the corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0027] If no, follow The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the second table, based on the corrected speed and the amplitude of the three-phase current, a corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0028] Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction;

[0029] The second table is a comparison table established in advance through bench calibration and used to represent the amplitudes of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

[0030] In one embodiment, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including:

[0031] Determining the sum of squares of three-phase currents of the permanent magnet synchronous motor;

[0032] According to a pre-established third table, based on the rotation speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the sum of the squares of the three-phase currents, a corresponding torque value is searched out from the third table, and the torque value searched out from the third table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0033] The third table is a comparison table established in advance by means of bench calibration to represent different bus voltages, different rotation speeds, and different sums of squares of three-phase currents and the corresponding absolute values ​​of electromagnetic torques.

[0034] In one embodiment, it further includes:

[0035] The output of the rotary transformer is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor by a current method.

[0036] In one implementation, based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined, including:

[0037] Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, according to The calculation method of I d Direction and I q direction;

[0038] When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1;

[0039] When sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1;

[0040] Among them, I a , I b and I c The A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are collected in sequence, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the rotary transformer, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is a calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1;

[0041] I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e )=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the reverse direction.

[0042] In one implementation, obtaining the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor includes:

[0043] Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, according to T e =|T e |·sign(T e) obtaining the electromagnetic torque of the permanent magnet synchronous motor;

[0044] Among them, T e represents the electromagnetic torque of the permanent magnet synchronous motor, |T e | represents the absolute value of the electromagnetic torque.

[0045] A monitoring system for electromagnetic torque, comprising:

[0046] A three-phase current acquisition module, used to collect the three-phase current of the permanent magnet synchronous motor after aligning the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer;

[0047] An electromagnetic torque absolute value determination module, used to determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the acquired rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current;

[0048] An electromagnetic torque direction determination module, used to determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer;

[0049] The electromagnetic torque determination module is used to obtain the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor.

[0050] In one implementation, the electromagnetic torque absolute value determination module is specifically used to:

[0051] Based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table.

[0052] In one implementation, the electromagnetic torque absolute value determination module includes:

[0053] A three-phase current square sum determination unit, used to determine the square sum of the three-phase current of the permanent magnet synchronous motor;

[0054] A judging unit, used to judge whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if yes, triggering the first executing unit, and if no, triggering the second executing unit;

[0055] The first execution unit is used to: according to a pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, find out the corresponding torque value from the first table, and use the torque value found out from the first table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0056] The second execution unit is used to: The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the first table, based on the corrected speed and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0057] Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction;

[0058] The first table is a comparison table established in advance through bench calibration and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

[0059] In one embodiment, it further includes an electric current monitoring module for:

[0060] The output of the rotary transformer is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor by a current method.

[0061] In one implementation, the electromagnetic torque direction determination module is specifically used to:

[0062] Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, according to The calculation method of I d Direction and I q direction;

[0063] When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1;

[0064] When sign(I d )=-1 and sign(Iq )=-1, determine sign(T e )=-1;

[0065] Among them, I a , I b and I c The A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are collected in sequence, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the rotary transformer, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is a calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1;

[0066] I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e )=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the reverse direction.

[0067] A monitoring device for electromagnetic torque, comprising:

[0068] Memory for storing computer programs;

[0069] A processor is used to execute the computer program to implement the steps of the electromagnetic torque monitoring method as described above.

[0070] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the electromagnetic torque monitoring method as described above are implemented.

[0071] By applying the technical solution provided by the embodiment of the present invention, it is considered that the absolute value of the electromagnetic torque and the direction of the electromagnetic torque can be determined respectively, so that the electromagnetic torque of the permanent magnet synchronous motor can be obtained accordingly. Specifically, the present application takes into account that there is a corresponding relationship between the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current and the absolute value of the electromagnetic torque, so it can be based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, and the absolute value of the electromagnetic torque of the permanent magnet synchronous motor can be conveniently and accurately determined. As for the direction of the electromagnetic torque, it is necessary to align the sampling moment of the three-phase current of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer, and then based on the collected three-phase current of the permanent magnet synchronous motor, and the sine envelope signal and cosine envelope signal output by the rotary transformer, the direction of the electromagnetic torque of the permanent magnet synchronous motor can be accurately determined. It can be seen that in the process of determining the direction of the electromagnetic torque of the permanent magnet synchronous motor, only the sine and cosine envelope signals output by the rotary transformer need to be used, and the output angle decoding of the rotary transformer is not required as in the traditional current method. Therefore, the solution of the present application can conveniently and accurately determine the direction of the electromagnetic torque of the permanent magnet synchronous motor.

[0072] In summary, the solution of the present application can accurately determine the electromagnetic torque of the permanent magnet synchronous motor, and is simple and convenient to implement, and takes a short time. In addition, compared with the traditional current method, the solution of the present application does not require the addition of additional hardware circuits, so the solution of the present application does not increase costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0074] Figure 1 It is a flow chart of an implementation of a method for monitoring electromagnetic torque in the present invention;

[0075] Figure 2 A schematic diagram of the principle of determining electromagnetic torque in a specific implementation manner of the present invention;

[0076] Figure 3 It is a structural schematic diagram of an electromagnetic torque monitoring system in the present invention;

[0077] Figure 4 It is a structural schematic diagram of an electromagnetic torque monitoring device in the present invention. DETAILED DESCRIPTION

[0078] The core of the present invention is to provide a method for monitoring electromagnetic torque, which can accurately determine the electromagnetic torque of a permanent magnet synchronous motor, and is simple and convenient to implement, and takes a short time. Compared with the traditional current method, the solution of the present application does not require the addition of additional hardware circuits, so the solution of the present application does not increase costs.

[0079] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0080] Please refer to Figure 1 , Figure 1 The following is a flow chart of an implementation of a method for monitoring electromagnetic torque in the present invention. The method for monitoring electromagnetic torque may include the following steps:

[0081] Step S101: after aligning the sampling time of the three-phase current of the permanent magnet synchronous motor with the equivalent angle time of the rotary transformer, collecting the three-phase current of the permanent magnet synchronous motor.

[0082] The monitoring of electromagnetic torque achieved in the present application specifically achieves the monitoring of the electromagnetic torque of a permanent magnet synchronous motor, that is, achieves the estimation of the electromagnetic torque of the permanent magnet synchronous motor.

[0083] When collecting the three-phase current of the permanent magnet synchronous motor, it can be achieved through a corresponding collection circuit or sensor. For example, in a common electric drive system, a related circuit is originally provided to realize the collection of the three-phase current. In addition, it should be noted that in some implementations, the three-phase current can be directly collected, and in some implementations, only any two phases of the three-phase current can be collected, and then the third phase is calculated based on the principle that the vector sum of the three-phase current is 0. The specific collection method can be set and adjusted according to actual needs, and does not affect the implementation of the present invention, as long as the three-phase current of the permanent magnet synchronous motor can be accurately collected.

[0084] In addition, when collecting the three-phase current of the permanent magnet synchronous motor, it is required to align the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer. This is because when the operation of step S103 is subsequently performed and the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined based on the three-phase current, it is necessary to ensure that the three-phase current sampling moment is aligned with the equivalent angle moment of the rotary transformer, so that the direction of the electromagnetic torque can be accurately obtained. In other words, for the subsequent step S102, regardless of whether the alignment requirement is met, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor can be accurately determined based on the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current.

[0085] In the scheme of the present application, it is necessary to align the three-phase current sampling moment of the permanent magnet synchronous motor to the equivalent angle moment of the rotary transformer. In other words, after decoding the output of the rotary transformer, an angle reflecting the position of the motor rotor can be obtained, and it is necessary to collect the three-phase current of the permanent magnet synchronous motor when the motor rotor is at this angle position.

[0086] Step S102: Based on the acquired rotation speed, bus voltage and three-phase current of the permanent magnet synchronous motor, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined.

[0087] The present application takes into account that there is a corresponding relationship between the speed, bus voltage and three-phase current of the permanent magnet synchronous motor and the absolute value of the electromagnetic torque. Therefore, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor can be determined based on the collected speed, bus voltage and three-phase current of the permanent magnet synchronous motor.

[0088] For example, in a specific scenario, a model can be established to reflect the corresponding relationship, that is, the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current are used as the input of the model, and the absolute value of the electromagnetic torque is used as the output of the model to construct the model. As for the specific form of the model and the value setting of related parameters, they can be set and adjusted based on theoretical analysis and / or experimental data, as long as the corresponding relationship between the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, and the absolute value of the electromagnetic torque can be accurately and effectively reflected.

[0089] For another example, in an implementation method described below, in order to improve the execution efficiency of step S102, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor can be determined based on a table lookup method. It can be understood that the table lookup method is equivalent to expressing the correspondence between the speed, bus voltage and three-phase current of the permanent magnet synchronous motor and the absolute value of the electromagnetic torque in the form of a table. Compared with the modeling implementation method exemplified above, the accuracy of the table lookup implementation method is slightly lower than that of the modeling implementation method, but it is very convenient and fast to implement, that is, the execution efficiency of this step is very high, the time consumption is very short, and there is no need to occupy too many computing resources.

[0090] Step S103: Determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer.

[0091] As described above, when executing the operation of step S103 to determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the three-phase current, it is necessary to ensure that the three-phase current sampling moment is aligned with the equivalent angle moment of the rotary transformer so that the direction of the electromagnetic torque can be accurately obtained.

[0092] When the three-phase current sampling moment is aligned with the equivalent angle moment of the resolver, the sine and cosine envelope signals output by the resolver can be directly used in combination with the three-phase current values ​​to calculate the direction of the electromagnetic torque without the need for angle decoding of the resolver, making the process of determining the direction of the electromagnetic torque of the permanent magnet synchronous motor more convenient.

[0093] In a specific implementation of the present invention, step S103 may specifically include:

[0094] Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the resolver, and the cosine envelope signal output by the resolver, The calculation method of I d Direction and I q direction;

[0095] When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1;

[0096] When sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1;

[0097] Among them, I a , I b and I c The collected currents are the A phase current, B phase current and C phase current of the permanent magnet synchronous motor, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the resolver, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is the calibration value, when the rotation direction of the resolver is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1;

[0098] I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e)=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the reverse direction.

[0099] This implementation method takes into account that when determining the direction of the electromagnetic torque of the permanent magnet synchronous motor, it is possible to first determine I d and I q direction, and after analysis and deduction, when the three-phase current sampling moment is aligned with the equivalent angle moment of the rotary transformer, the d-axis component I d Direction sign(I d ) can be obtained by To obtain, and for the q-axis component I of the three-phase current q Direction sign(I q ), in this implementation mode, it can be achieved by Come get.

[0100] Determine I d Direction sign(I d ) and I q Direction sign(I q ), the direction of the electromagnetic torque can be determined accordingly. As described above, when sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1, that is, the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive, and when sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1, that is, the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the opposite direction.

[0101] Step S104: obtaining the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor.

[0102] According to the above description, after obtaining the absolute value of the electromagnetic torque and the direction of the electromagnetic torque, the electromagnetic torque of the permanent magnet synchronous motor can be obtained.

[0103] For example, in a specific implementation of the present invention, step S104 may specifically include:

[0104] Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, according to T e =|T e |·sign(Te ) to obtain the electromagnetic torque of the permanent magnet synchronous motor; where T e represents the electromagnetic torque of the permanent magnet synchronous motor, |T e | represents the absolute value of electromagnetic torque, sign(T e ) indicates the direction of the electromagnetic torque.

[0105] In a specific implementation of the present invention, step S102 may specifically include:

[0106] Based on the collected speed, bus voltage and three-phase current of the permanent magnet synchronous motor, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up the table.

[0107] As described above, there is a corresponding relationship between the rotational speed, bus voltage and three-phase current of the permanent magnet synchronous motor and the absolute value of the electromagnetic torque of the permanent magnet synchronous motor. In this implementation, the corresponding relationship can be reflected in a table, so that the execution speed of step S102 can be effectively guaranteed when the impact on accuracy is relatively low.

[0108] Further, in a specific implementation of the present invention, step S102 may specifically include:

[0109] Determine the sum of squares of the three-phase currents of the permanent magnet synchronous motor;

[0110] According to a third table established in advance, based on the rotation speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the sum of the squares of the three-phase currents, the corresponding torque value is found from the third table, and the torque value found from the third table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0111] The third table is a comparison table established in advance by means of bench calibration to represent different bus voltages, different rotation speeds, and different sums of squares of three-phase currents and the corresponding absolute values ​​of electromagnetic torques.

[0112] As described above, there is a corresponding relationship between the rotation speed, bus voltage and three-phase current of the permanent magnet synchronous motor and the absolute value of the electromagnetic torque of the permanent magnet synchronous motor, and the corresponding relationship can be reflected by a table.

[0113] This implementation further takes into account that, when other conditions remain unchanged, the bus voltage is proportional to the absolute value of the electromagnetic torque; when other conditions remain unchanged, the speed of the permanent magnet synchronous motor is proportional to the absolute value of the electromagnetic torque; when other conditions remain unchanged, the sum of the squares of the three-phase currents of the permanent magnet synchronous motor is proportional to the absolute value of the electromagnetic torque. Therefore, in this implementation, it is considered that the speed of the permanent magnet synchronous motor, the bus voltage, and the sum of the squares of the three-phase currents can be used as three independent variables, and the absolute value of the electromagnetic torque can be used as the dependent variable, and the bench calibration is performed in advance to establish a third table, that is, the third table established is specifically used to represent the correspondence between different bus voltages, different speeds, and different sums of the squares of the three-phase currents and the corresponding absolute values ​​of the electromagnetic torque.

[0114] It can be seen that in this implementation, after collecting the three-phase current, the square sum needs to be calculated, which can be expressed as Then, the corresponding absolute value of the electromagnetic torque can be found from the third table in combination with the rotational speed and bus voltage.

[0115] In addition, in the aforementioned implementation, the speed of the permanent magnet synchronous motor, the bus voltage and the sum of the squares of the three-phase current are used as independent variables, and the absolute value of the electromagnetic torque is used as the dependent variable to achieve the establishment of the third table. In other implementations, other forms of independent variables can also be used as long as they can reflect the corresponding relationship between the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current and the absolute value of the electromagnetic torque. For example, in one occasion, the sum of the squares of the three-phase current in this implementation can be replaced by That is, it is replaced by the amplitude of the three-phase current. It represents the sum of the squares of the three-phase currents.

[0116] In a specific implementation of the present invention, step S102 may specifically include:

[0117] Determine the sum of squares of the three-phase currents of the permanent magnet synchronous motor;

[0118] Determine whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage;

[0119] If yes, then according to the pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents, the corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0120] If no, follow The collected speed of the permanent magnet synchronous motor is corrected by a correction method, and according to the first table, based on the corrected speed and the sum of the squares of the three-phase currents, the corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0121] Among them, U dc_cal It represents the first voltage, U dc_cur represents the bus voltage of the permanent magnet synchronous motor, ω represents the speed of the permanent magnet synchronous motor, * It indicates the speed of the permanent magnet synchronous motor after correction;

[0122] The first table is a comparison table established in advance by means of bench calibration under a set first voltage and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques.

[0123] As can be seen from the above description, in the above implementation, the third table uses the speed of the permanent magnet synchronous motor, the bus voltage and the square sum of the three-phase current as independent variables, and the absolute value of the electromagnetic torque as the dependent variable. This implementation scheme with three independent variables will make the data volume of the third table larger. In particular, in some occasions, when it is necessary to determine a more accurate absolute value of the electromagnetic torque, it is necessary to set more value points for the independent variable, that is, the change step of the independent variable needs to be set smaller, resulting in a large amount of data in the third table.

[0124] In this embodiment, when the bench calibration is performed, the bus voltage is constant, that is, the bus voltage is equal to the preset first voltage U dc_cal , for example, in practical applications, the first voltage can be selected as the rated voltage. Therefore, in this implementation, the first table obtained by bench calibration represents a comparison table established under the set first voltage to represent the sum of the squares of different three-phase currents at different speeds and the corresponding absolute values ​​of the electromagnetic torque. That is to say, in this implementation, the first table takes the speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents as independent variables, and the absolute value of the electromagnetic torque as the dependent variable, so that this implementation has only two independent variables, so the amount of data in the first table is small, making the calibration process more convenient, that is, during calibration, the bus voltage can be constant, and it is only necessary to determine the absolute value of the electromagnetic torque under different speeds and different sums of the squares of the three-phase currents.

[0125] In this implementation, a first table is pre-established, and when step S102 is subsequently executed, the corresponding torque value can be found from the first table based on the independent variable of the first table. It can be understood that if the bus voltage of the permanent magnet synchronous motor collected is equal to the preset first voltage, it means that the current actual bus voltage is consistent with the first voltage during calibration. Therefore, the corresponding torque value can be directly found from the first table based on the speed of the permanent magnet synchronous motor and the square sum of the three-phase current, and the torque value found from the first table is used as the absolute value of the electromagnetic torque of the permanent magnet synchronous motor determined, that is, no speed correction is required at this time.

[0126] If the collected bus voltage of the permanent magnet synchronous motor is not equal to the preset first voltage, the speed needs to be corrected. In this implementation, The collected speed of the permanent magnet synchronous motor is corrected by a correction method, and then based on the corrected speed and the sum of the squares of the three-phase currents, the corresponding torque value is found from the first table, and the torque value is used as the absolute value of the electromagnetic torque of the permanent magnet synchronous motor.

[0127] See also Figure 2 , is a schematic diagram of the principle of determining the electromagnetic torque in a specific implementation method, Figure 2 The δ in the equation represents That is, it represents the ratio of the first voltage used during calibration to the actually collected bus voltage. This ratio can be used to correct the speed, so that when the actually collected bus voltage is different from the first voltage, a table lookup can be achieved based on the first table of this implementation method.

[0128] In a specific implementation of the present invention, step S102 may specifically include:

[0129] Determine the amplitude of the three-phase current of the permanent magnet synchronous motor; wherein the amplitude of the three-phase current of the permanent magnet synchronous motor I a , I b and I c The A phase current, B phase current and C phase current of the permanent magnet synchronous motor are collected respectively.

[0130] Determine whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage;

[0131] If yes, then according to the pre-established second table, based on the rotation speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, the corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0132] If no, follow The collected speed of the permanent magnet synchronous motor is corrected by a correction method, and according to the second table, based on the corrected speed and the amplitude of the three-phase current, the corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0133] Among them, U dc_cal It represents the first voltage, U dc_cur represents the bus voltage of the permanent magnet synchronous motor, ω represents the speed of the permanent magnet synchronous motor, * It indicates the speed of the permanent magnet synchronous motor after correction;

[0134] The second table is a comparison table established in advance by means of bench calibration under a set first voltage and used to represent the amplitudes of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques.

[0135] In the above implementation, the first table takes the speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents as independent variables, and the absolute value of the electromagnetic torque as the dependent variable, so that there are only two independent variables in the first table. Therefore, the amount of data in the first table is small, making the calibration process more convenient.

[0136] In this implementation, the principle is similar to the above, the difference is that the amplitude of the three-phase current is used in this implementation instead of the square sum. The rest can refer to the description of the above implementation, and will not be repeated here.

[0137] It can be understood that in this implementation, the second table takes the speed of the permanent magnet synchronous motor and the amplitude of the three-phase current as independent variables, and the absolute value of the electromagnetic torque as the dependent variable, so that there are only two independent variables in the second table. Therefore, the second table also has the advantages of smaller data volume and more convenient calibration process.

[0138] In practical applications, in addition to using the sum of squares of the three-phase currents or the amplitudes of the three-phase currents in the above implementations, other implementations may also use other forms that can effectively reflect the three-phase currents.

[0139] In a specific embodiment of the present invention, it may also include:

[0140] The output of the resolver is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor using the current method.

[0141] As described above, when the system needs to reach a higher safety level, it is usually necessary to achieve redundancy in the monitoring method. The present application takes into account that the scheme of the present application is very convenient and fast to implement, and the scheme of the present application does not need to add additional hardware circuits compared to the traditional current method. Therefore, in practical applications, if a higher safety level needs to be achieved, the scheme of the present application can also support two monitoring methods at the same time, one is the monitoring method for determining the electromagnetic torque based on the absolute value and direction of the electromagnetic torque described in detail above, and the other is the current method, that is, according to the description of this implementation method, the output of the rotary transformer is decoded, so as to determine the electromagnetic torque of the permanent magnet synchronous motor by the current method, that is, the present application can also support the current method at the same time to achieve redundancy in the monitoring method without adding additional hardware circuits.

[0142] By applying the technical solution provided by the embodiment of the present invention, it is considered that the absolute value of the electromagnetic torque and the direction of the electromagnetic torque can be determined respectively, so that the electromagnetic torque of the permanent magnet synchronous motor can be obtained accordingly. Specifically, the present application takes into account that there is a corresponding relationship between the speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current and the absolute value of the electromagnetic torque, so it can be based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, and the absolute value of the electromagnetic torque of the permanent magnet synchronous motor can be conveniently and accurately determined. As for the direction of the electromagnetic torque, it is necessary to align the sampling moment of the three-phase current of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer, and then based on the collected three-phase current of the permanent magnet synchronous motor, and the sine envelope signal and cosine envelope signal output by the rotary transformer, the direction of the electromagnetic torque of the permanent magnet synchronous motor can be accurately determined. It can be seen that in the process of determining the direction of the electromagnetic torque of the permanent magnet synchronous motor, only the sine and cosine envelope signals output by the rotary transformer need to be used, and the output angle decoding of the rotary transformer is not required as in the traditional current method. Therefore, the solution of the present application can conveniently and accurately determine the direction of the electromagnetic torque of the permanent magnet synchronous motor.

[0143] In summary, the solution of the present application can accurately determine the electromagnetic torque of the permanent magnet synchronous motor, and is simple and convenient to implement, and takes a short time. In addition, compared with the traditional current method, the solution of the present application does not require the addition of additional hardware circuits, so the solution of the present application does not increase costs.

[0144] Corresponding to the above method embodiment, an embodiment of the present invention further provides an electromagnetic torque monitoring system, which can be referred to in correspondence with the above.

[0145] See also Figure 3 FIG. 1 is a schematic diagram of the structure of an electromagnetic torque monitoring system in the present invention, comprising:

[0146] A three-phase current acquisition module 301 is used to collect the three-phase current of the permanent magnet synchronous motor after aligning the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer;

[0147] The electromagnetic torque absolute value determination module 302 is used to determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the acquired speed, bus voltage and three-phase current of the permanent magnet synchronous motor;

[0148] The electromagnetic torque direction determination module 303 is used to determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer;

[0149] The electromagnetic torque determination module 304 is used to obtain the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor.

[0150] In a specific implementation of the present invention, the electromagnetic torque absolute value determination module 302 is specifically used to:

[0151] Based on the collected speed, bus voltage and three-phase current of the permanent magnet synchronous motor, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up the table.

[0152] In a specific implementation of the present invention, the electromagnetic torque absolute value determination module 302 includes:

[0153] A three-phase current square sum determination unit, used to determine the square sum of the three-phase current of the permanent magnet synchronous motor;

[0154] A judging unit, used to judge whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if yes, triggering the first executing unit, and if no, triggering the second executing unit;

[0155] The first execution unit is used to: according to a pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents, find out the corresponding torque value from the first table, and use the torque value found out from the first table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0156] The second execution unit is used to: The collected speed of the permanent magnet synchronous motor is corrected by a correction method, and according to the first table, based on the corrected speed and the sum of the squares of the three-phase currents, the corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0157] Among them, U dc_cal It represents the first voltage, U dc_cur represents the bus voltage of the permanent magnet synchronous motor, ω represents the speed of the permanent magnet synchronous motor, * It indicates the speed of the permanent magnet synchronous motor after correction;

[0158] The first table is a comparison table established in advance by means of bench calibration under a set first voltage and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques.

[0159] In a specific implementation of the present invention, the electromagnetic torque absolute value determination module 302 includes:

[0160] The three-phase current amplitude determination unit is used to determine the amplitude of the three-phase current of the permanent magnet synchronous motor; wherein the amplitude of the three-phase current of the permanent magnet synchronous motor I a , I b and I c The collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively;

[0161] A judging unit, used to judge whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if yes, triggering the third executing unit, and if no, triggering the fourth executing unit;

[0162] The third execution unit is used to: according to the pre-established second table, based on the rotation speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, find out the corresponding torque value from the second table, and use the torque value found out from the second table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0163] The fourth execution unit is used to: The collected speed of the permanent magnet synchronous motor is corrected by a correction method, and according to the second table, based on the corrected speed and the amplitude of the three-phase current, the corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0164] Among them, U dc_cal It represents the first voltage, U dc_cur represents the bus voltage of the permanent magnet synchronous motor, ω represents the speed of the permanent magnet synchronous motor, * It indicates the speed of the permanent magnet synchronous motor after correction;

[0165] The second table is a comparison table established in advance by means of bench calibration under a set first voltage and used to represent the amplitudes of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques.

[0166] In a specific implementation of the present invention, the electromagnetic torque absolute value determination module 302 is specifically used to:

[0167] Determine the sum of squares of the three-phase currents of the permanent magnet synchronous motor;

[0168] According to a third table established in advance, based on the rotation speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the sum of the squares of the three-phase currents, the corresponding torque value is found from the third table, and the torque value found from the third table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0169] The third table is a comparison table established in advance by means of bench calibration to represent different bus voltages, different rotation speeds, and different sums of squares of three-phase currents and the corresponding absolute values ​​of electromagnetic torques.

[0170] In a specific embodiment of the present invention, an electric current method monitoring module is also included, which is used to:

[0171] The output of the resolver is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor using the current method.

[0172] In a specific implementation of the present invention, the electromagnetic torque direction determination module 303 is specifically used to:

[0173] Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the resolver, and the cosine envelope signal output by the resolver, The calculation method of I d Direction and I q direction;

[0174] When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1;

[0175] When sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1;

[0176] Among them, I a , I b and I cThe collected currents are the A phase current, B phase current and C phase current of the permanent magnet synchronous motor, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the resolver, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is the calibration value, when the rotation direction of the resolver is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1;

[0177] I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e )=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the reverse direction.

[0178] In a specific implementation of the present invention, the electromagnetic torque determination module 304 is specifically used to:

[0179] Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, according to T e =|T e |·sign(T e ) obtains the electromagnetic torque of the permanent magnet synchronous motor;

[0180] Among them, T e represents the electromagnetic torque of the permanent magnet synchronous motor, |T e |Indicates the absolute value of electromagnetic torque.

[0181] Corresponding to the above method and system embodiments, the present invention also provides an electromagnetic torque monitoring device and a computer-readable storage medium.

[0182] See also Figure 4 , the electromagnetic torque monitoring device may include:

[0183] Memory 401, used for storing computer programs;

[0184] The processor 402 is used to execute a computer program to implement the steps of the electromagnetic torque monitoring method in any of the above embodiments.

[0185] The computer readable storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the electromagnetic torque monitoring method in any of the above embodiments are implemented. The computer readable storage medium mentioned here includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the technical field.

[0186] It should also be noted that, in this application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0187] Those skilled in the art may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0188] The present application uses specific examples to illustrate the principles and implementation methods of the present invention, and the description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A method for monitoring electromagnetic torque, characterized in that: include: After aligning the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer, collecting the three-phase current of the permanent magnet synchronous motor; Determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current; Determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer; Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, the electromagnetic torque of the permanent magnet synchronous motor is obtained.

2. The method for monitoring electromagnetic torque according to claim 1, characterized in that: The determining of the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current comprises: Based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table.

3. The method for monitoring electromagnetic torque according to claim 2, characterized in that: The absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including: Determining the sum of squares of three-phase currents of the permanent magnet synchronous motor; Determining whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; If yes, then according to a pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; If no, follow The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the first table, based on the corrected speed and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction; The first table is a comparison table established in advance through bench calibration and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

4. The method for monitoring electromagnetic torque according to claim 2, characterized in that: The absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including: Determine the amplitude of the three-phase current of the permanent magnet synchronous motor; wherein the amplitude of the three-phase current of the permanent magnet synchronous motor I a , I b and I c The collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively; Determining whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; If yes, then according to a pre-established second table, based on the rotation speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, the corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; If no, follow The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the second table, based on the corrected speed and the amplitude of the three-phase current, a corresponding torque value is found from the second table, and the torque value found from the second table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction; The second table is a comparison table established in advance through bench calibration and used to represent the amplitudes of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

5. The method for monitoring electromagnetic torque according to claim 2, characterized in that: The absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, including: Determining the sum of squares of three-phase currents of the permanent magnet synchronous motor; According to a pre-established third table, based on the rotation speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the sum of the squares of the three-phase currents, a corresponding torque value is searched out from the third table, and the torque value searched out from the third table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; The third table is a comparison table established in advance by means of bench calibration to represent different bus voltages, different rotation speeds, and different sums of squares of three-phase currents and the corresponding absolute values ​​of electromagnetic torques.

6. The method for monitoring electromagnetic torque according to claim 1, characterized in that: Also includes: The output of the rotary transformer is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor by a current method.

7. The method for monitoring electromagnetic torque according to any one of claims 1 to 6, characterized in that: Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined, including: Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, according to The calculation method of I d Direction and I q direction; When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1; When sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1; Among them, I a , I b and I c The A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are collected in sequence, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the rotary transformer, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is a calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1; I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e )=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined to be in the reverse direction.

8. The method for monitoring electromagnetic torque according to claim 7, characterized in that: Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, the electromagnetic torque of the permanent magnet synchronous motor is obtained, including: Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, according to T e =|T e |·sign(T e ) obtaining the electromagnetic torque of the permanent magnet synchronous motor; Among them, T e represents the electromagnetic torque of the permanent magnet synchronous motor, |T e | represents the absolute value of the electromagnetic torque.

9. A system for monitoring electromagnetic torque, characterized in that: include: A three-phase current acquisition module, used to collect the three-phase current of the permanent magnet synchronous motor after aligning the three-phase current sampling moment of the permanent magnet synchronous motor with the equivalent angle moment of the rotary transformer; An electromagnetic torque absolute value determination module, used to determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the acquired rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current; An electromagnetic torque direction determination module, used to determine the direction of the electromagnetic torque of the permanent magnet synchronous motor based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer; The electromagnetic torque determination module is used to obtain the electromagnetic torque of the permanent magnet synchronous motor based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor.

10. The electromagnetic torque monitoring system according to claim 9, characterized in that: The electromagnetic torque absolute value determination module is specifically used for: Based on the collected rotation speed of the permanent magnet synchronous motor, the bus voltage and the three-phase current, the absolute value of the electromagnetic torque of the permanent magnet synchronous motor is determined by looking up a table.

11. The electromagnetic torque monitoring system according to claim 10, characterized in that: The electromagnetic torque absolute value determination module comprises: A three-phase current square sum determination unit, used to determine the square sum of the three-phase current of the permanent magnet synchronous motor; A judging unit, used to judge whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if yes, triggering the first executing unit, and if no, triggering the second executing unit; The first execution unit is used to: according to a pre-established first table, based on the rotation speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, find out the corresponding torque value from the first table, and use the torque value found out from the first table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; The second execution unit is used to: The collected speed of the permanent magnet synchronous motor is corrected in a correction manner, and according to the first table, based on the corrected speed and the square sum of the three-phase currents, a corresponding torque value is found from the first table, and the torque value found from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; Among them, U dc_cal represents the first voltage, U dc_cur represents the collected bus voltage of the permanent magnet synchronous motor, ω represents the collected speed of the permanent magnet synchronous motor, ω * It represents the speed of the permanent magnet synchronous motor after correction; The first table is a comparison table established in advance through bench calibration and used to represent the sum of squares of different three-phase currents at different speeds and the corresponding absolute values ​​of electromagnetic torques under the set first voltage.

12. The electromagnetic torque monitoring system according to claim 9, characterized in that: Also includes an amperometric monitoring module for: The output of the rotary transformer is decoded to determine the electromagnetic torque of the permanent magnet synchronous motor by a current method.

13. The electromagnetic torque monitoring system according to any one of claims 9 to 12, characterized in that: The electromagnetic torque direction determination module is specifically used for: Based on the collected three-phase current of the permanent magnet synchronous motor, the sine envelope signal output by the rotary transformer, and the cosine envelope signal output by the rotary transformer, according to The calculation method of I d Direction and I q direction; When sign(I d )=-1 and sign(I q )=1, determine sign(T e )=1; When sign(I d )=-1 and sign(I q )=-1, determine sign(T e )=-1; Among them, I a , I b and I c The A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are collected in sequence, V cos is the cosine envelope signal output by the resolver, V sin is the sinusoidal envelope signal output by the rotary transformer, sign is the sign function, is the initial zero angle of the permanent magnet synchronous motor, γ is a calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor, γ is 1, otherwise γ is -1; I d is the d-axis component of the three-phase current, I q is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When sign(T e )=1, it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. e )=-1, it indicates that the direction of the determined electromagnetic torque of the permanent magnet synchronous motor is the reverse direction.

14. An electromagnetic torque monitoring device, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the computer program to implement the steps of the electromagnetic torque monitoring method as claimed in any one of claims 1 to 8.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the electromagnetic torque monitoring method according to any one of claims 1 to 8 are implemented.

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