A method, system, device and storage medium for monitoring electromagnetic torque

Abstract

The application discloses a kind of electromagnetic torque monitoring method, system, equipment and storage medium, applied to electric drive system monitoring technical field, comprising: after the three-phase current sampling time of permanent magnet synchronous motor is aligned with the equivalent angle time of rotary transformer, the three-phase current of permanent magnet synchronous motor is collected;Based on the rotational speed of the permanent magnet synchronous motor collected, bus voltage and three-phase current, the absolute value of the electromagnetic torque of permanent magnet synchronous motor is determined;Based on the three-phase current of the permanent magnet synchronous motor collected, the sine envelope signal output by rotary transformer and the cosine envelope signal output by rotary transformer, the direction of the electromagnetic torque of permanent magnet synchronous motor is determined;Based on the absolute value and direction of the electromagnetic torque determined, the electromagnetic torque of permanent magnet synchronous motor is obtained.The scheme of the application can accurately determine the electromagnetic torque of permanent magnet synchronous motor, and is simple and convenient to realize, time-consuming is shorter, and will not increase cost additionally.

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, the functional safety of new energy electric vehicles has received increasing attention. The electric drive system is the core power component of an electric vehicle, controlling the drive motor to generate the torque required for vehicle operation. Therefore, any increase or decrease in "unintended torque" poses a risk to the vehicle's safe operation. To improve safety, it is necessary to monitor the electric drive system's torque, which requires real-time estimation of the motor's electromagnetic torque.

[0003] In the prior art, when estimating the electromagnetic torque of a motor, there are two commonly used methods: 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 acquire 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 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] Furthermore, when a system requires a higher safety level, the conventional approach is to combine the current and power methods to achieve redundancy in monitoring. This restricts electromagnetic torque estimation to two separate algorithms, complicating the system and increasing hardware costs while also making software implementation more challenging.

[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 currently needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] The purpose 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 speed, bus voltage and three-phase current of the permanent magnet synchronous motor;

[0012] Determining 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] The electromagnetic torque of the permanent magnet synchronous motor is obtained based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor.

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

[0015] Based on the collected rotational 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, determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes:

[0017] Determining the sum of squares of the 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 speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, a corresponding torque value is searched from the first table, and the torque value searched 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 Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the first table based on the corrected speed and the sum of the squares of the three-phase currents according to the first table, and using the torque value found in the first table 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 bus voltage of the permanent magnet synchronous motor collected, ω represents the speed of the permanent magnet synchronous motor collected, 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 test 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, determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes:

[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, searching for a corresponding torque value from a pre-established second table based on the speed of the permanent magnet synchronous motor and the amplitude of the three-phase current according to the second table, and using the torque value found from the second table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor;

[0027] If no, follow Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the second table based on the corrected speed and the amplitude of the three-phase current according to the second table, and using the torque value found from the second table 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 bus voltage of the permanent magnet synchronous motor collected, ω represents the speed of the permanent magnet synchronous motor collected, 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, determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up a table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes:

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

[0032] According to a pre-established third table, based on the speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the square sum of the three-phase currents, a corresponding torque value is searched from the third table, and the torque value searched 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 through bench calibration to represent different bus voltages, different speeds, and different sums of squares of three-phase currents and 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 embodiment, determining 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 resolver, and the cosine envelope signal output by the resolver includes:

[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 to determine 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 collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are 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 a 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;

[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 determined electromagnetic torque of the permanent magnet synchronous motor is in the reverse direction.

[0042] In one embodiment, 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 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;

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

[0048] an electromagnetic torque direction determination module, configured 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 resolver, and the cosine envelope signal output by the resolver;

[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 embodiment, the electromagnetic torque absolute value determination module is specifically configured to:

[0051] Based on the collected rotational 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 embodiment, the electromagnetic torque absolute value determination module includes:

[0053] a three-phase current square sum determining unit, configured to determine the square sum of the three-phase currents of the permanent magnet synchronous motor;

[0054] a judgment unit, configured to judge whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if so, triggering the first execution unit; if not, triggering the second execution unit;

[0055] The first execution unit is configured to: search for a corresponding torque value from a pre-established first table based on the rotational speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, and use the torque value searched 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: Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the first table based on the corrected speed and the sum of the squares of the three-phase currents according to the first table, and using the torque value found in the first table 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 bus voltage of the permanent magnet synchronous motor collected, ω represents the speed of the permanent magnet synchronous motor collected, 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 test 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, the system further includes an amperometric 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 embodiment, the electromagnetic torque direction determination module is specifically configured 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 to determine 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 collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are 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 a 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;

[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 determined electromagnetic torque of the permanent magnet synchronous motor is 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, which, when executed by a processor, implements the steps of the electromagnetic torque monitoring method as described above.

[0071] By applying the technical solution provided in the embodiments of the present invention, the absolute value of the electromagnetic torque and the direction of the electromagnetic torque can be determined respectively, thereby obtaining the electromagnetic torque of the permanent magnet synchronous motor. Specifically, the present application takes into account the 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, 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 can be determined more conveniently and accurately. As for the direction of the electromagnetic torque, it is necessary to align the sampling time of the three-phase current of the permanent magnet synchronous motor with the equivalent angle time 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 are needed, without the need to decode the output angle of the rotary transformer 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 a permanent magnet synchronous motor, and is simple, convenient, and time-saving to implement. In addition, compared to the traditional current method, the solution of the present application does not require 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

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

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

[0076] Figure 3 Schematic diagram of the structure of an electromagnetic torque monitoring system in the present invention;

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

[0078] The core of this invention is to provide a method for monitoring electromagnetic torque, which can accurately determine the electromagnetic torque of a permanent magnet synchronous motor. It is simple, convenient, and time-efficient to implement. Furthermore, compared to traditional current methods, this method does not require additional hardware circuitry, thus minimizing costs.

[0079] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without 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 method of an electromagnetic torque monitoring method of the present invention. The electromagnetic torque monitoring method 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, the three-phase current of the permanent magnet synchronous motor is collected.

[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, this can be achieved through corresponding collection circuits or sensors. For example, in a typical electric drive system, relevant circuits are already provided to enable the collection of three-phase current. It should also be noted that in some embodiments, the three-phase current can be directly collected, while in some embodiments, only any two phases of the three-phase current can be collected, and the third phase can be calculated based on the principle that the vector sum of the three-phase currents 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] Furthermore, when collecting the three-phase current of the permanent magnet synchronous motor, it is required to align the sampling time of the three-phase current of the permanent magnet synchronous motor with the equivalent angle time of the resolver. This is because when the direction of the electromagnetic torque of the permanent magnet synchronous motor is determined based on the three-phase current in the subsequent step S103, the three-phase current sampling time must be aligned with the equivalent angle time of the resolver to accurately determine the direction of the electromagnetic torque. In other words, for the subsequent step S102, regardless of whether this 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, bus voltage, and three-phase current of the permanent magnet synchronous motor.

[0085] In the solution 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: determining the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected rotational speed, bus voltage and three-phase current of the permanent magnet synchronous motor.

[0087] This 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, bus voltage and three-phase current of the permanent magnet synchronous motor 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, bus voltage and three-phase current of the permanent magnet synchronous motor and the absolute value of the electromagnetic torque can be accurately and effectively reflected.

[0089] For example, in one embodiment described below, 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. It is understood that using a table lookup 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 a tabular form. Compared to the modeling implementation method described above, the table lookup implementation method is slightly less accurate than the modeling implementation method, but it is very convenient and quick to implement, resulting in high execution efficiency of this step, a short execution time, and no need to occupy excessive computing resources.

[0090] Step S103: determining 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 resolver, and the cosine envelope signal output by the resolver.

[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 time is aligned with the equivalent angle time 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 embodiment 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, according to The calculation method to determine 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 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 embodiment 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 achieved through 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 and direction of the electromagnetic torque, the electromagnetic torque of the permanent magnet synchronous motor can be obtained.

[0103] For example, in a specific embodiment 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 embodiment 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 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 embodiment, the corresponding relationship can be reflected in a table, so that the execution speed of step S102 can be effectively guaranteed while the impact on accuracy is relatively low.

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

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

[0110] According to a pre-established third table, based on the speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the square sum of the three-phase currents, a corresponding torque value is searched from the third table, and the torque value searched 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 through bench calibration to represent different bus voltages, different 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 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, and the corresponding relationship can be reflected in a table.

[0113] This embodiment further takes into account that, with other conditions unchanged, the bus voltage is proportional to the absolute value of the electromagnetic torque; with other conditions unchanged, the speed of the permanent magnet synchronous motor is proportional to the absolute value of the electromagnetic torque; and with other conditions 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 embodiment, considering 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, a bench calibration can be performed in advance to establish a third table. That is, the established third table is specifically used to represent the corresponding relationship 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 speed and bus voltage.

[0115] In addition, in the aforementioned embodiment, 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 embodiments, 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 embodiment 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 embodiment of the present invention, step S102 may specifically include:

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

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

[0119] If yes, then according to a pre-established first table, based on the speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents, a corresponding torque value is searched from the first table, and the torque value searched 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 using 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, 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;

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

[0122] The first table is a comparison table established in advance through bench calibration at a set first voltage, and is 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 permanent magnet synchronous motor speed, bus voltage, 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. This implementation with three independent variables results in a large amount of data in the third table. In particular, in some cases where a more precise determination of the absolute value of the electromagnetic torque is required, a larger number of independent variable value points must be set, meaning that the step size of the independent variable changes must be 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 embodiment, 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 embodiment, the first table uses 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 embodiment has only two independent variables. Therefore, 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 embodiment, a first table is pre-established, and subsequently, when step S102 is executed, the corresponding torque value can be retrieved from the first table based on the independent variable of the first table. It is understood that if the acquired bus voltage of the permanent magnet synchronous motor 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 retrieved from the first table based on the speed of the permanent magnet synchronous motor and the square sum of the three-phase currents. The torque value retrieved from the first table is used as the absolute value of the electromagnetic torque of the permanent magnet synchronous motor. In other words, no speed correction is required at this time.

[0126] If the bus voltage of the permanent magnet synchronous motor collected is not equal to the preset first voltage, the speed needs to be corrected. In this implementation, the speed can be corrected according to 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 Figure 2 , is a schematic diagram of the principle of determining 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 performed based on the first table of this implementation method.

[0128] In a specific embodiment 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 collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively

[0130] Determining whether the collected 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 speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, the corresponding torque value is searched from the second table, and the torque value searched 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 using a correction method, 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;

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

[0134] 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 a set first voltage.

[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 instead of the square sum. The rest can be found in 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 a smaller amount of data and a more convenient calibration process.

[0138] In practical applications, in addition to using the sum of the squares of the three-phase currents or the amplitudes of the three-phase currents in the above embodiments, other forms may be used in other embodiments as long as they can effectively reflect the three-phase currents.

[0139] In a specific embodiment of the present invention, it may further 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 achieve a higher safety level, it is usually necessary to implement redundancy in the monitoring method. The present application takes into account that the solution of the present application is very convenient and fast to implement, and the solution of the present application does not require the addition of additional hardware circuits compared to the traditional current method. Therefore, in practical applications, if it is necessary to achieve a higher safety level, the solution of the present application can also support two monitoring methods at the same time, one of which 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 embodiment, 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 in the embodiments of the present invention, the absolute value of the electromagnetic torque and the direction of the electromagnetic torque can be determined respectively, thereby obtaining the electromagnetic torque of the permanent magnet synchronous motor. Specifically, the present application takes into account the 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, 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 can be determined more conveniently and accurately. As for the direction of the electromagnetic torque, it is necessary to align the sampling time of the three-phase current of the permanent magnet synchronous motor with the equivalent angle time 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 are needed, without the need to decode the output angle of the rotary transformer 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 a permanent magnet synchronous motor, and is simple, convenient, and time-saving to implement. In addition, compared to the traditional current method, the solution of the present application does not require 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 according to 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 time of the permanent magnet synchronous motor with the equivalent angle time 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 collected 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 resolver, and the cosine envelope signal output by the resolver;

[0149] The electromagnetic torque determination module 304 is configured 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 embodiment of the present invention, the electromagnetic torque absolute value determination module 302 is specifically configured 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 embodiment 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 currents of the permanent magnet synchronous motor;

[0154] A judgment unit, configured to judge whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if so, triggering the first execution unit; if not, triggering the second execution unit;

[0155] The first execution unit is configured to: according to a pre-established first table, based on the rotational speed of the permanent magnet synchronous motor and the sum of the squares of the three-phase currents, search for a corresponding torque value from the first table, and use the torque value searched 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 using 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, 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;

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

[0158] The first table is a comparison table established in advance through bench calibration at a set first voltage, and is 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 embodiment 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 judgment unit, configured to judge whether the acquired bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if so, triggering the third execution unit; if not, triggering the fourth execution unit;

[0162] The third execution unit is configured to: according to a pre-established second table, based on the speed of the permanent magnet synchronous motor and the amplitude of the three-phase current, look up a corresponding torque value from the second table, and use the torque value found in 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 using a correction method, 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;

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

[0165] 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 a set first voltage.

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

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

[0168] According to a pre-established third table, based on the speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the square sum of the three-phase currents, a corresponding torque value is searched from the third table, and the torque value searched 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 through bench calibration to represent different bus voltages, different 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 monitoring module is further 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 embodiment of the present invention, the electromagnetic torque direction determination module 303 is specifically configured 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, according to The calculation method to determine 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 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 embodiment of the present invention, the electromagnetic torque determination module 304 is specifically configured 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 ) obtain 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 the 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 Figure 4 , the electromagnetic torque monitoring device may include:

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

[0184] The processor 402 is configured 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, which, when executed by a processor, implements the steps of the electromagnetic torque monitoring method described in any of the above embodiments. The computer-readable storage medium herein includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art.

[0186] It should also be noted that, in this application, relational terms such as first and second, etc. are merely 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 "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[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 in 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 can 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] Specific examples are used in this application to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the technical solutions and core concepts of the present invention. It should be noted that, for those skilled in the art, various improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such 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 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 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; 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; Determining 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 includes: 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 direction and direction; when and When ; when and When ; in, , as well as The collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively, is the cosine envelope signal output by the rotary transformer, 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, is the calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor is 1, otherwise is -1; is the d-axis component of the three-phase current, is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When , it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. , it indicates that the direction of the determined electromagnetic torque of the permanent magnet synchronous motor is in the opposite direction.

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 speed, bus voltage, and three-phase current of the permanent magnet synchronous motor includes: Based on the collected rotational 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 determining of the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up the table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes: Determining the sum of squares of the 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 speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, a corresponding torque value is searched from the first table, and the torque value searched from the first table is used as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; If no, follow Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the first table based on the corrected speed and the sum of the squares of the three-phase currents according to the first table, and using the torque value found in the first table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; in, represents the first voltage, It represents the bus voltage of the permanent magnet synchronous motor collected. It represents the collected speed of the permanent magnet synchronous motor. It represents the speed of the permanent magnet synchronous motor after correction; The first table is a comparison table established in advance through test 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 determining of the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up the table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes: 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 , , as well as 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, searching for a corresponding torque value from a pre-established second table based on the speed of the permanent magnet synchronous motor and the amplitude of the three-phase current according to the second table, and using the torque value found from the second table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; If no, follow Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the second table based on the corrected speed and the amplitude of the three-phase current according to the second table, and using the torque value found from the second table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; in, represents the first voltage, It represents the bus voltage of the permanent magnet synchronous motor collected. It represents the collected speed of the permanent magnet synchronous motor. 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 determining of the absolute value of the electromagnetic torque of the permanent magnet synchronous motor by looking up the table based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current includes: Determining the sum of squares of the three-phase currents of the permanent magnet synchronous motor; According to a pre-established third table, based on the speed of the permanent magnet synchronous motor, the bus voltage of the permanent magnet synchronous motor, and the square sum of the three-phase currents, a corresponding torque value is searched from the third table, and the torque value searched 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 through bench calibration to represent different bus voltages, different speeds, and different sums of squares of three-phase currents and 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 claim 1, characterized in that: 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: Based on the determined absolute value of the electromagnetic torque and the direction of the electromagnetic torque of the permanent magnet synchronous motor, Obtaining the electromagnetic torque of the permanent magnet synchronous motor; Among them, T e represents the electromagnetic torque of the permanent magnet synchronous motor, represents the absolute value of the electromagnetic torque.

8. A system for monitoring electromagnetic torque, characterized in that: include: A three-phase current acquisition module 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; an electromagnetic torque absolute value determination module, configured to determine the absolute value of the electromagnetic torque of the permanent magnet synchronous motor based on the collected speed of the permanent magnet synchronous motor, the bus voltage, and the three-phase current; an electromagnetic torque direction determination module, configured 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 resolver, and the cosine envelope signal output by the resolver; an electromagnetic torque determination module, configured 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; The electromagnetic torque direction determination module is specifically used to: 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 direction and direction; when and When ; when and When ; in, , as well as The collected A-phase current, B-phase current and C-phase current of the permanent magnet synchronous motor are respectively, is the cosine envelope signal output by the rotary transformer, 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, is the calibration value, when the rotation direction of the rotary transformer is consistent with the mechanical rotation direction of the permanent magnet synchronous motor is 1, otherwise is -1; is the d-axis component of the three-phase current, is the q-axis component of the three-phase current, T e Represents the electromagnetic torque of the permanent magnet synchronous motor. When , it indicates that the direction of the electromagnetic torque of the permanent magnet synchronous motor is positive. , it indicates that the direction of the determined electromagnetic torque of the permanent magnet synchronous motor is in the opposite direction.

9. The electromagnetic torque monitoring system according to claim 8, characterized in that: The electromagnetic torque absolute value determination module is specifically used to: Based on the collected rotational 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.

10. The electromagnetic torque monitoring system according to claim 9, characterized in that: The electromagnetic torque absolute value determination module includes: a three-phase current square sum determining unit, configured to determine the square sum of the three-phase currents of the permanent magnet synchronous motor; a judgment unit, configured to judge whether the collected bus voltage of the permanent magnet synchronous motor is equal to a preset first voltage; if so, triggering the first execution unit; if not, triggering the second execution unit; The first execution unit is configured to: search for a corresponding torque value from a pre-established first table based on the rotational speed of the permanent magnet synchronous motor and the square sum of the three-phase currents, and use the torque value searched 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: Correcting the acquired speed of the permanent magnet synchronous motor using a correction method, and searching for a corresponding torque value from the first table based on the corrected speed and the sum of the squares of the three-phase currents according to the first table, and using the torque value found in the first table as the determined absolute value of the electromagnetic torque of the permanent magnet synchronous motor; in, represents the first voltage, It represents the bus voltage of the permanent magnet synchronous motor collected. It represents the collected speed of the permanent magnet synchronous motor. It represents the speed of the permanent magnet synchronous motor after correction; The first table is a comparison table established in advance through test 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.

11. The electromagnetic torque monitoring system according to claim 8, 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.

12. 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 according to any one of claims 1 to 7.

13. 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 7 are implemented.

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