A method and device for determining electromagnetic torque of a permanent magnet synchronous motor

Abstract

The present invention discloses a method and device for determining the electromagnetic torque of a permanent magnet synchronous motor, comprising: obtaining a first parameter set of the permanent magnet synchronous motor in the previous operating cycle; updating the parameters of the permanent magnet synchronous motor in the current operating cycle based on the first parameter set to obtain a second parameter; calculating iron loss power based on a second current parameter and a first motor electrical angular velocity parameter; calculating an equivalent iron loss resistance based on a second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; determining an iron loss current based on the equivalent iron loss resistance; and calculating the electromagnetic torque of the current operating cycle based on the second current parameter, the second flux linkage parameter, and the iron loss current, so that the permanent magnet synchronous motor rotation angle is updated based on the electromagnetic torque. The present invention introduces iron loss calculation into a nonlinear model with d-q axis current as a state variable, realizes high-precision iron loss power calculation with relatively small storage requirements, and thereby improves the accuracy of the electromagnetic torque.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a method and device for determining the electromagnetic torque of a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motors have been widely used in industrial fields such as high-performance speed control systems and servo control systems. The permanent magnet synchronous motor model is of great significance to the research on permanent magnet synchronous motor driving methods. Electromagnetic torque can usually be obtained through the permanent magnet synchronous motor model.

[0003] Currently, a dq-axis equivalent circuit model is used to perform steady-state analysis or dynamic simulation of permanent magnet synchronous motors. This method deviates significantly from the actual characteristics of the motor because, in actual analysis, constant inductance cannot describe electromagnetic saturation, cross-coupling, and spatial harmonic characteristics. There is also a time-step finite element joint simulation method based on field-circuit coupling. This method requires a transient finite element solution of the motor's electromagnetic field at each time step, but the calculation is time-consuming and cannot meet the needs of rapid motor design optimization and control software optimization. There are also modeling methods that use magnetic circuits, but the calculation accuracy is not high. The existing table lookup method based on finite element static magnetostatic analysis results is not accurate in calculating iron loss and cannot meet high-precision application scenarios.

[0004] It can be seen that the existing methods of obtaining electromagnetic torque by modeling permanent magnet synchronous motors all have problems such as poor model accuracy, large data resource occupation, and poor iron loss estimation, which makes the final electromagnetic torque poorly accurate and unable to meet actual control requirements. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a method and device for determining the electromagnetic torque of a permanent magnet synchronous motor, thereby improving the precision of the permanent magnet synchronous motor model and the accuracy of the electromagnetic torque.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for determining the electromagnetic torque of a permanent magnet synchronous motor, comprising:

[0008] Obtain a first parameter set of the permanent magnet synchronous motor in the last operating cycle, the first parameter set including at least a first current parameter, a first flux linkage parameter, a first tangential inductance parameter, a first voltage parameter, and a first motor electrical angular velocity parameter of the dq axes corresponding to the last operating cycle;

[0009] updating the parameters of the permanent magnet synchronous motor in the current operation cycle based on the first parameter set to obtain a second parameter set, where the second parameter set includes at least a second current parameter and a second flux linkage parameter corresponding to the current operation cycle;

[0010] Calculating the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter;

[0011] Calculating an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter;

[0012] determining an iron loss current according to the equivalent iron loss resistance;

[0013] Based on the second current parameter, the second flux parameter and the iron loss current, the electromagnetic torque of this operation cycle is calculated, so that the permanent magnet synchronous motor rotation angle is updated based on the electromagnetic torque.

[0014] Optionally, obtaining a first parameter set of the permanent magnet synchronous motor in a previous cycle includes:

[0015] Obtaining a first current parameter of the permanent magnet synchronous motor in the previous cycle;

[0016] A first flux linkage parameter and a first tangent inductance parameter are obtained by looking up the first current parameter in a first parameter table. The first parameter table is a two-dimensional table with the current parameter as input, and the first flux linkage parameter and the first tangent inductance parameter in the first parameter table are affected by both the d-axis current and the q-axis current.

[0017] Optionally, calculating the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter includes:

[0018] Searching a second parameter table based on the second current parameter to obtain an initial iron loss power parameter that matches the second current parameter;

[0019] The iron loss power is determined according to the initial iron loss power parameter and the first motor electrical angular velocity parameter, wherein the second parameter table is a two-dimensional table recording current parameters and iron loss power parameters.

[0020] Optionally, determining the iron loss power according to the initial iron loss power parameter and the first motor electrical angular velocity parameter includes:

[0021] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated using the same reference electrical angular velocity parameter, the iron loss power parameter is calculated based on the reference electrical angular velocity parameter, the initial iron loss power parameter, and the first motor electrical angular velocity parameter to obtain the iron loss power;

[0022] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under different reference electrical angular velocity parameters, determining the target reference electrical angular velocity parameter based on the second current parameter;

[0023] The iron loss power is obtained by performing calculation based on the target reference electrical angular velocity, the initial iron loss power parameter, and the first motor electrical angular velocity parameter.

[0024] Optionally, the calculating the electromagnetic torque of the current operation cycle based on the second current parameter, the second flux parameter, and the iron loss current includes:

[0025] Calculating dq-axis current components that generate electromagnetic torque based on the second current parameter and the iron loss current;

[0026] The electromagnetic torque of this operation cycle is calculated based on the current component and the second flux parameter.

[0027] A device for determining electromagnetic torque of a permanent magnet synchronous motor, comprising:

[0028] an acquisition unit, configured to acquire a first parameter set of the permanent magnet synchronous motor in a previous operating cycle, wherein the first parameter set includes at least a first current parameter, a first flux linkage parameter, a first tangential inductance parameter, a first voltage parameter, and a first motor electrical angular velocity parameter of the dq axes corresponding to the previous operating cycle;

[0029] an updating unit, configured to update the parameters of the permanent magnet synchronous motor in the current operation cycle based on the first parameter set to obtain a second parameter set, wherein the second parameter set includes at least a second current parameter and a second flux linkage parameter corresponding to the current operation cycle;

[0030] A first calculation unit is configured to calculate the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter;

[0031] a second calculating unit, configured to calculate an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter;

[0032] A first determining unit, configured to determine an iron loss current according to the equivalent iron loss resistance;

[0033] The third calculation unit is used to calculate the electromagnetic torque of this operation cycle based on the second current parameter, the second flux parameter and the iron loss current, so as to update the permanent magnet synchronous motor angle based on the electromagnetic torque.

[0034] Optionally, the acquiring unit includes:

[0035] A first acquisition subunit is used to obtain a first current parameter of the permanent magnet synchronous motor in the previous cycle;

[0036] The first table lookup subunit is configured to obtain a first flux linkage parameter and a first tangent inductance parameter by looking up a first parameter table according to the first current parameter, where the first parameter table is a two-dimensional table with the current parameter as input, and the first flux linkage parameter and the first tangent inductance parameter in the first parameter table are affected by both the d-axis current and the q-axis current.

[0037] Optionally, the first computing unit includes:

[0038] a second table lookup subunit, configured to query a second parameter table based on the second current parameter to obtain an initial iron loss power parameter matching the second current parameter;

[0039] The first determining subunit is used to determine the iron loss power according to the initial iron loss power parameter and the first motor electrical angular velocity parameter, wherein the second parameter table is a two-dimensional table recording current parameters and iron loss power parameters.

[0040] Optionally, the first determining subunit is specifically configured to:

[0041] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated using the same reference electrical angular velocity parameter, the iron loss power parameter is calculated based on the reference electrical angular velocity parameter, the initial iron loss power parameter, and the first motor electrical angular velocity parameter to obtain the iron loss power;

[0042] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under different reference electrical angular velocity parameters, determining the target reference electrical angular velocity parameter based on the second current parameter;

[0043] The iron loss power is obtained by performing calculation based on the target reference electrical angular velocity, the initial iron loss power parameter, and the first motor electrical angular velocity parameter.

[0044] Optionally, the third calculation unit includes:

[0045] a second calculation subunit, configured to calculate, based on the second current parameter and the iron loss current, a dq-axis current component generating an electromagnetic torque;

[0046] The third calculation subunit is configured to calculate the electromagnetic torque of the current operation cycle according to the current component and the second flux linkage parameter.

[0047] Compared to the prior art, the present invention provides a method and device for determining the electromagnetic torque of a permanent magnet synchronous motor, comprising: obtaining a first parameter set of the permanent magnet synchronous motor in the previous operating cycle; updating the parameters of the permanent magnet synchronous motor for the current operating cycle based on the first parameter set to obtain a second parameter; calculating iron loss power based on a second current parameter and a first motor electrical angular velocity parameter; calculating an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; determining an iron loss current based on the equivalent iron loss resistance; and calculating the electromagnetic torque for the current operating cycle based on the second current parameter, the second flux linkage parameter, and the iron loss current, thereby updating the permanent magnet synchronous motor's rotation angle based on the electromagnetic torque. The present invention introduces iron loss calculation into a nonlinear model with dq axis currents as state variables, achieving high-precision iron loss power calculation with minimal storage requirements, thereby improving the accuracy of the electromagnetic torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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 merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0049] Figure 1 A flow chart of a method for determining the electromagnetic torque of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0050] Figure 2 A schematic structural diagram of a device for determining the electromagnetic torque of a permanent magnet synchronous motor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] In an embodiment of the present invention, a method for determining the electromagnetic torque of a permanent magnet synchronous motor is provided. In this method, the electromagnetic torque is obtained through a high-precision model of the permanent magnet synchronous motor in an embodiment of the present invention. The model is a nonlinear model based on dq-axis current as a state variable, and a processing model for iron loss calculation based on CAE (Computer Aided Engineering) or test results is introduced.

[0053] See also Figure 1, is a flow chart of a method for determining the electromagnetic torque of a permanent magnet synchronous motor provided by an embodiment of the present invention. The method may include the following steps:

[0054] S101: Obtain a first parameter set of the permanent magnet synchronous motor in the previous operation cycle.

[0055] The previous operating cycle is determined relative to the current operating cycle, which is the current operating cycle. Specifically, the previous operating cycle can be the last cycle in which the permanent magnet synchronous motor was controlled, or the last cycle in which the software controlling the permanent magnet synchronous motor was executed. For example, the software runs at a certain period, such as every 1us or every 1ms. During each execution, the system state corresponding to the current cycle is calculated. For example, if the current cycle corresponds to the 5th second, the system states at the 5th second are calculated for the current cycle. If the software's operating period is 1ms, the system states at the 5.001st second are calculated for the next cycle.

[0056] It should be noted that in the embodiment of the present invention, "first" and "second" are only used to distinguish parameters with the same name in different cycles. For example, the parameters in the previous operating cycle and the parameters in the current operating cycle can be distinguished by "first" and "second", that is, the current parameters are included in the previous operating cycle and the current operating cycle. In order to distinguish them, the current parameter of the previous operating cycle is recorded as the first current parameter, and the current parameter of the current operating cycle is recorded as the second current parameter.

[0057] Correspondingly, the first parameter set includes at least the first current parameter, first flux parameter, first tangent inductance parameter, and first motor electrical angular velocity parameter of the dq axis corresponding to the previous operating cycle. In addition, the first parameter set also includes a first voltage parameter, which is a control variable and is the voltage parameter of the dq axis corresponding to the mid-operation period of the previous operating cycle as a control input. In the control of permanent magnet synchronous motors, in order to obtain control characteristics similar to those of a DC motor, a coordinate system is established on the motor rotor. This coordinate system rotates synchronously with the rotor, and the direction of the rotor magnetic field is taken as the d axis, and the direction perpendicular to the rotor magnetic field is taken as the q axis. By converting the mathematical model of the motor into this coordinate system, the decoupling of the d axis and the q axis can be achieved, thereby obtaining good control characteristics.

[0058] In a possible embodiment, obtaining the first parameter set of the permanent magnet synchronous motor in the previous cycle includes: obtaining the first current parameter of the permanent magnet synchronous motor in the previous cycle; looking up the first magnetic flux parameter and the first tangent inductance parameter in a first parameter table according to the first current parameter, the first parameter table being a two-dimensional table with the current parameter as input, and the first magnetic flux parameter in the first parameter table is affected by both the d-axis current and the q-axis current, and the first tangent inductance parameter is also affected by both the d-axis and q-axis currents.

[0059] The first current parameter includes i d ,i q , calculate the i d ,i q The corresponding dq-axis first magnetic flux parameter λ d and λ q , and the i d ,i q The corresponding first tangent inductance parameter L dd , L qq , L dq , L qd Among them, λ d and λ q It can be found from a pre-made table, which can be derived from CAE analysis or test data. d and λ q It can also be obtained by online calculation method. dd , L qq , L dq , L qd It can be found by looking up a table with pre-made values, or by obtaining it online.

[0060] It should be noted that if the pre-made table is used, the dq axis flux λ d and λ q Can be made into i d ,i q is the two-dimensional table of input, i.e. d =(λ d ,λ q ) and λ q =(λ d ,λ q The flux linkage parameters are affected not only by the d-axis current but also by the q-axis current, thus reflecting the true cross-coupling characteristics of the motor. The corresponding tangent inductance parameters are also affected by each current parameter.

[0061] S102: Update the parameters of the permanent magnet synchronous motor in this operation cycle based on the first parameter set.

[0062] After obtaining the first parameter set, the parameters of the permanent magnet synchronous motor in this operation cycle are updated according to the parameters in the first parameter set to obtain the second parameter set, wherein the second parameter set at least includes the second current parameter and the second flux linkage parameter corresponding to this operation cycle. For example, using the dq axis voltage equation with current as the state variable and considering the cross coupling, the last cycle i d ,i q , dq axis control voltage v d , v q 、Motor electrical angular velocity ω e As input, calculate the current cycle i d ,i a The voltage equation used in this embodiment is shown in formula (1). In formula (1), R s is the winding resistance, Δt is the calculation step, L is L dd , L qq , L dq , L qd The matrix is shown in formula (2).

[0063]

[0064]

[0065] S103: Calculate and obtain iron loss power according to the second current parameter and the first motor electrical angular velocity parameter.

[0066] After obtaining the updated second parameter set, the iron loss power is updated. To improve calculation accuracy, in an embodiment of the present invention, based on an iron loss table obtained by finite element calculation or testing, and further reducing the amount of table data, the table for querying and obtaining the iron loss power in an embodiment of the present invention is a two-dimensional table corresponding to current parameters and iron loss power parameters. The two-dimensional table can effectively reduce the use of storage resources during data storage, which will be described in detail in subsequent embodiments of the present invention. Specifically, the iron loss power can be obtained by querying the second parameter table based on the second current parameter, wherein the second parameter table is a two-dimensional table recording the current parameters and the iron loss power parameters.

[0067] S104 : Calculate an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter.

[0068] S105 : Determine the iron loss current according to the equivalent iron loss resistance.

[0069] S106. Calculate the electromagnetic torque of this operation cycle based on the second current parameter, the second flux parameter, and the iron loss current.

[0070] To determine the iron loss current, the iron loss resistance can be determined first. The iron loss current is then determined based on the iron loss resistance. The dq-axis current components that generate the electromagnetic torque are then calculated based on the second voltage input, the second current parameter, and the iron loss current. The electromagnetic torque for the current cycle is then calculated based on these current components and the second flux linkage parameter. Once the electromagnetic torque is obtained, it can be used in the mechanical equation to update the motor angle.

[0071] The present invention provides a method for determining the electromagnetic torque of a permanent magnet synchronous motor, comprising: obtaining a first parameter set of the permanent magnet synchronous motor in the previous operating cycle; updating the parameters of the permanent magnet synchronous motor in the current operating cycle based on the first parameter set to obtain a second parameter; calculating iron loss power based on a second current parameter and a first motor electrical angular velocity parameter; calculating an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; determining an iron loss current based on the equivalent iron loss resistance; and calculating the electromagnetic torque in the current operating cycle based on the second current parameter, the second flux linkage parameter, and the iron loss current, so that the permanent magnet synchronous motor rotation angle is updated based on the electromagnetic torque. The present invention introduces iron loss calculation into a nonlinear model with dq axis currents as state variables, thereby improving the model accuracy and the accuracy of the electromagnetic torque.

[0072] In an embodiment of the present invention, the iron loss power is calculated based on the second current parameter and the first motor electrical angular velocity parameter, including: querying in a second parameter table based on the second current parameter to obtain an initial iron loss power parameter that matches the second current parameter; and determining the iron loss power based on the initial iron loss power parameter and the first motor electrical angular velocity parameter.

[0073] Among them, the second parameter table is a two-dimensional table that records current parameters and iron loss power parameters. When there is only one second parameter table, the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated based on the same reference electrical angular velocity parameter. At this time, there is only one reference electrical angular velocity parameter. The ratio of the first motor electrical angular velocity parameter to the reference electrical angular velocity parameter can be calculated, and then calculated with the initial iron loss power parameter obtained by looking up the table based on the second current parameter to obtain the iron loss power.

[0074] In another embodiment, the second parameter table can also be a set of two-dimensional parameter tables. The corresponding reference electric angular velocity in each parameter table in the group may be different, but the two-dimensional parameter table also only records the correspondence between the current parameter and the iron loss power parameter. The corresponding iron loss parameter, i.e., the iron loss component, can be obtained by querying in each parameter table based on the second current parameter. If there are two parameter tables in the set of tables, there will be two sets of iron loss parameters, and there will be at least two different reference electric angular velocities. At this time, it is necessary to determine the target reference electric angular velocity parameter based on the correspondence between the second current parameter and the reference electric angular velocity. Specifically, it can be determined by recording the table of the correspondence between the reference electric angular velocity and the current parameter. After determining the target reference electric angular velocity parameter, the ratio of the first motor electric angular velocity parameter to the target reference electric angular velocity parameter is obtained. The iron loss power can be calculated based on the reference iron loss component speed correction parameter and each iron loss power parameter obtained by query. Please refer to formula (3) in the following embodiment description. In this way, what is stored in the embodiment of the present invention is a two-dimensional table, which effectively reduces the storage space occupancy rate compared to the three-dimensional table corresponding to the storage angular velocity, current parameter and iron loss power. In addition, when generating the second parameter table, it is not necessary to complete the calculation of iron loss power under all current parameters under the same angular velocity parameter. The second parameter table can also be generated in the scenario where the angular velocity changes or the test is performed at intervals, and it does not affect the use of subsequent tables.

[0075] Specifically, the second parameter table is a table for querying the value of the iron loss component. A fixed reference speed ω is obtained through CAE or experiment. e_base Or at some reference speed, all reference iron loss components are listed in Table P Fe base_1 (i d ,i q ), P Febase_2 (i d ,i q ),...P Febase_n (i d ,i q ), and according to the current working point i d ,i q , check these tables and get the i d ,i q The corresponding reference iron loss component value is given below. d ,i q Corresponding to a reference speed. Each current point i d ,i a The reference iron loss is equal to the sum of all reference iron loss components at this current point. The reference iron loss component table can also be fitted into i d ,i q The form of a polynomial, using the polynomial to calculate the id ,i q The reference iron loss component value is easy to operate and can cover all i in the current circle. d ,i q Considering these two aspects, it is preferred to take a fixed speed below the motor base speed as the reference speed ω e_base , with ω e_base The iron loss component table under the speed is used as the reference iron loss component table. If a fixed speed is not selected as the reference speed, that is, P Fe_base_1 (i d ,i q ), P Fe_base_2 (i d ,i q ),...P Fe_base_n (i d ,i q ) in different i d ,i q′ If the points correspond to at least 2 or more different speeds, it is necessary to store these different speed values and (i d ,i q ) mapping relationship.

[0076] Use the following formula to calculate the actual ω of this current point e The iron loss value under the following conditions. Where k1, k2, ... kn are the exponents of the speed correction of the reference iron loss component. P is calculated by the following formula Fe (ω e ,i d ,i q ) is the iron loss power corresponding to the second current parameter and the first motor electrical angular velocity parameter.

[0077]

[0078] After obtaining the iron loss power, according to the updated second flux parameter λ d ,λ q and the electrical angular velocity of the first motor, and use formula (4) to calculate the equivalent iron loss resistance.

[0079]

[0080] In an embodiment of the present invention, after determining the equivalent iron loss resistance, the iron loss current can be further calculated. Specifically, this can be accomplished through two implementation methods. In one possible implementation method, the iron loss current is obtained by calculating the equivalent iron loss resistance, the updated second current parameter, and the second voltage parameter. See equations (5) and (6) in the specific implementation process below. In another implementation method, the iron loss current can be obtained by calculating the equivalent iron loss resistance, the first motor electrical angular velocity parameter, and the second magnetic flux parameter. See equations (7) and (8) in the specific implementation process below.

[0081] Specifically, update the dq axis iron loss current i cd and i cq . It is preferred to use the current cycle control voltage input v according to equations (5) and (6). d , v q , the second current parameter i updated in this operation cycle d ,i q , equivalent iron loss resistance R c In addition, according to formula (7) and formula (8), the last operating cycle ω e , updated second flux parameter λ d and λ q , Updated equivalent iron loss resistance R c , and the dq axis flux change rate Calculate. Can be updated by λ d ,λ q and λ before update d ,λ q Perform the difference to obtain .

[0082]

[0083]

[0084]

[0085]

[0086] According to equations (9) and (10), as well as the second current parameter of this operation cycle, the dq axis iron loss current i cd and i cq , calculate the dq axis current component i that generates electromagnetic torque od and i oq .

[0087] i od =i d -i cd (9)

[0088] i oq =i q -l cq (10)

[0089] Based on the updated second flux parameter and the updated current component, the electromagnetic torque T of this operation cycle is calculated. e .

[0090] It should be noted that, in the embodiment of the present application, at least two 2D tables P need to be saved. Fe_base_1 (i d ,i q ) and P Fe_base_2 (i d ,i q ), you can set any speed, any i d ,i q If the traditional method is used, a three-dimensional table P Fe (ω e ,i d ,i q ), the speed dimension of the three-dimensional table is composed of several different test speeds (for example: 1000rpm, 2000rpm...8000rpm...), which is equivalent to a two-dimensional table P at several different speeds. Fe (i d ,i q The more speeds tested, that is, the longer the speed dimension array of the three-dimensional table is, the more accurate the calculation result will be. Obviously, the method of using only two tables in this embodiment requires less storage capacity.

[0091] Based on the above embodiment, another embodiment of the present application further provides a device for determining the electromagnetic torque of a permanent magnet synchronous motor, see Figure 2 ,include:

[0092] An acquisition unit 10 is configured to acquire a first parameter set of the permanent magnet synchronous motor in a previous operating cycle, wherein the first parameter set includes at least a first current parameter, a first flux linkage parameter, a first tangential inductance parameter, a first voltage parameter, and a first motor electrical angular velocity parameter of the dq axes corresponding to the previous operating cycle;

[0093] an updating unit 20, configured to update the parameters of the permanent magnet synchronous motor in the current operation cycle based on the first parameter set to obtain a second parameter set, wherein the second parameter set includes at least a second current parameter and a second flux linkage parameter corresponding to the current operation cycle;

[0094] A first calculation unit 30 is configured to calculate the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter;

[0095] A second calculation unit 40 is configured to calculate an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter;

[0096] A first determining unit 50 is configured to determine an iron loss current according to the equivalent iron loss resistance;

[0097] The third calculation unit 60 is used to calculate the electromagnetic torque of this operation cycle based on the second current parameter, the second flux parameter and the iron loss current, so as to update the permanent magnet synchronous motor angle based on the electromagnetic torque.

[0098] In a possible implementation, the acquiring unit includes:

[0099] A first acquiring subunit is configured to acquire a first current parameter of the permanent magnet synchronous motor in the previous cycle;

[0100] The first table lookup subunit is configured to obtain a first flux linkage parameter and a first tangent inductance parameter by looking up a first parameter table according to the first current parameter, where the first parameter table is a two-dimensional table with the current parameter as input, and the first flux linkage parameter and the first tangent inductance parameter in the first parameter table are affected by both the d-axis current and the q-axis current.

[0101] Furthermore, the first calculation unit includes:

[0102] a second table lookup subunit, configured to query a second parameter table based on the second current parameter to obtain an initial iron loss power parameter matching the second current parameter;

[0103] The first determining subunit is used to determine the iron loss power according to the initial iron loss power parameter and the first motor electrical angular velocity parameter, wherein the second parameter table is a two-dimensional table recording current parameters and iron loss power parameters.

[0104] Optionally, the first determining subunit is specifically configured to:

[0105] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated using the same reference electrical angular velocity parameter, the iron loss power parameter is calculated based on the reference electrical angular velocity parameter, the initial iron loss power parameter, and the first motor electrical angular velocity parameter to obtain the iron loss power;

[0106] If the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under different reference electrical angular velocity parameters, determining the target reference electrical angular velocity parameter based on the second current parameter;

[0107] The iron loss power is obtained by performing calculation based on the target reference electrical angular velocity, the initial iron loss power parameter, and the first motor electrical angular velocity parameter.

[0108] Furthermore, the third calculation unit includes:

[0109] a second calculation subunit, configured to calculate, based on the second current parameter and the iron loss current, a dq-axis current component generating an electromagnetic torque;

[0110] The third calculation subunit is configured to calculate the electromagnetic torque of the current operation cycle according to the current component and the second flux linkage parameter.

[0111] The present invention provides a device for determining the electromagnetic torque of a permanent magnet synchronous motor, comprising: obtaining a first parameter set of the permanent magnet synchronous motor in the previous operating cycle; updating the parameters of the permanent magnet synchronous motor in the current operating cycle based on the first parameter set to obtain a second parameter; calculating iron loss power based on a second current parameter and a first motor electrical angular velocity parameter; calculating an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; determining an iron loss current based on the equivalent iron loss resistance; and calculating the electromagnetic torque in the current operating cycle based on the second current parameter, the second flux linkage parameter, and the iron loss current, so that the permanent magnet synchronous motor rotation angle is updated based on the electromagnetic torque. The present invention introduces iron loss calculation into a nonlinear model with dq axis currents as state variables, thereby improving the model accuracy and the accuracy of the electromagnetic torque.

[0112] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0113] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the electromagnetic torque of a permanent magnet synchronous motor, characterized in that: include: Obtain a first parameter set of the permanent magnet synchronous motor in the last operating cycle, the first parameter set including at least a first current parameter, a first flux linkage parameter, a first tangential inductance parameter, a first voltage parameter, and a first motor electrical angular velocity parameter of the dq axes corresponding to the last operating cycle; updating the parameters of the permanent magnet synchronous motor in the current operation cycle based on the first parameter set to obtain a second parameter set, where the second parameter set includes at least a second current parameter and a second flux linkage parameter corresponding to the current operation cycle; Calculate the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter; wherein, the calculating the iron loss power according to the second current parameter and the first motor electrical angular velocity parameter includes: querying in a second parameter table based on the second current parameter to obtain an initial iron loss power parameter matching the second current parameter; determining the iron loss power according to the initial iron loss power parameter and the first motor electrical angular velocity parameter, wherein the second parameter table is a two-dimensional table recording current parameters and iron loss power parameters; determining the iron loss power according to the initial iron loss power parameter and the first motor electrical angular velocity parameter includes: if the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under the same reference electrical angular velocity parameter, calculating based on the reference electrical angular velocity parameter, the initial iron loss power parameter, and the first motor electrical angular velocity parameter to obtain the iron loss power; if the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under different reference electrical angular velocity parameters, determining a target reference electrical angular velocity parameter based on the second current parameter; and calculating based on the target reference electrical angular velocity, the initial iron loss power parameter, and the first motor electrical angular velocity parameter to obtain the iron loss power; Calculating an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; Determining the iron loss current according to the equivalent iron loss resistance; Based on the second current parameter, the second flux parameter and the iron loss current, the electromagnetic torque of this operation cycle is calculated, so that the permanent magnet synchronous motor rotation angle is updated based on the electromagnetic torque.

2. The method according to claim 1, characterized in that The obtaining of a first parameter set of the permanent magnet synchronous motor in a previous cycle includes: Obtaining a first current parameter of the permanent magnet synchronous motor in the previous cycle; A first flux linkage parameter and a first tangent inductance parameter are obtained by looking up the first current parameter in a first parameter table. The first parameter table is a two-dimensional table with the current parameter as input, and the first flux linkage parameter and the first tangent inductance parameter in the first parameter table are affected by both the d-axis current and the q-axis current.

3. The method according to claim 1, characterized in that The calculating the electromagnetic torque of the current operation cycle based on the second current parameter, the second flux parameter, and the iron loss current includes: Calculating dq-axis current components that generate electromagnetic torque based on the second current parameter and the iron loss current; The electromagnetic torque of this operation cycle is calculated based on the current component and the second flux parameter.

4. A device for determining the electromagnetic torque of a permanent magnet synchronous motor, characterized in that: include: an acquisition unit, configured to acquire a first parameter set of the permanent magnet synchronous motor in a previous operating cycle, wherein the first parameter set includes at least a first current parameter, a first flux linkage parameter, a first tangential inductance parameter, a first voltage parameter, and a first motor electrical angular velocity parameter of the dq axes corresponding to the previous operating cycle; an updating unit, configured to update the parameters of the permanent magnet synchronous motor in the current operation cycle based on the first parameter set to obtain a second parameter set, wherein the second parameter set includes at least a second current parameter and a second flux linkage parameter corresponding to the current operation cycle; A first calculation unit is configured to calculate and obtain the iron loss power based on the second current parameter and the first motor electrical angular velocity parameter; wherein the first calculation unit includes: a second table lookup subunit, configured to query in a second parameter table based on the second current parameter to obtain an initial iron loss power parameter matching the second current parameter; a first determination subunit, configured to obtain the iron loss power by performing calculation based on the reference electrical angular velocity parameter, the initial iron loss power parameter, and the first motor electrical angular velocity parameter if the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under the same reference electrical angular velocity parameter; if the iron loss power parameter corresponding to each current parameter in the second parameter table is calculated under different reference electrical angular velocity parameters, determining a target reference electrical angular velocity parameter based on the second current parameter; and obtaining the iron loss power by performing calculation based on the target reference electrical angular velocity, the initial iron loss power parameter, and the first motor electrical angular velocity parameter, wherein the second parameter table is a two-dimensional table recording current parameters and iron loss power parameters; a second calculating unit, configured to calculate an equivalent iron loss resistance based on the second flux linkage parameter, the iron loss power, and the first motor electrical angular velocity parameter; A first determining unit, configured to determine an iron loss current according to the equivalent iron loss resistance; The third calculation unit is used to calculate the electromagnetic torque of this operation cycle based on the second current parameter, the second flux parameter and the iron loss current, so as to update the permanent magnet synchronous motor angle based on the electromagnetic torque.

5. The device according to claim 4, characterized in that The acquisition unit includes: A first acquisition subunit is used to obtain a first current parameter of the permanent magnet synchronous motor in the previous cycle; The first table lookup subunit is configured to obtain a first flux linkage parameter and a first tangent inductance parameter by looking up a first parameter table according to the first current parameter, where the first parameter table is a two-dimensional table with the current parameter as input, and the first flux linkage parameter and the first tangent inductance parameter in the first parameter table are affected by both the d-axis current and the q-axis current.

6. The device according to claim 4, characterized in that The third computing unit includes: a second calculation subunit, configured to calculate, based on the second current parameter and the iron loss current, a dq-axis current component generating an electromagnetic torque; The third calculation subunit is configured to calculate the electromagnetic torque of the current operation cycle according to the current component and the second flux linkage parameter.

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