KR20200022731A - Final Output Data Interpolation Error Improvement for Look-up Table Based PMSM Control Method - Google Patents

Abstract

Disclosed are a method and a device for controlling a permanent magnet synchronous motor (PMSM). According to an embodiment of the present invention, the method for controlling a PMSM receives a speed and a torque command of a rotor of the PMSM, and uses a look-up table related to motor current values to obtain dq-axis current values corresponding to the speed and the torque command of the rotor, compensates an error of maximum output torque by using a maximum output torque table for each speed, and interpolates the dq-axis current values by using the compensated maximum output torque.

Description

Final Output Data Interpolation Error Improvement for Look-up Table Based PMSM Control Method

The present invention relates to a method and apparatus for compensating maximum torque control error in a permanent magnet synchronous motor.

Recently, a permanent magnet synchronous motor (PMSM) driving system having a low volume and high output power has been applied to a vehicle electric motor.

For vehicle application of the permanent magnet synchronous motor driving system, a method of driving and storing appropriate data in a look-up table (LUT) according to a control input for a user or an environment change is generally used. However, there is a limit to the data that can be stored in the lookup table, and you cannot store the appropriate data for all environment inputs. In addition, as vehicle safety standards are getting higher, the amount of memory that can be used in the driving field is also increasingly limited.

In order to solve this problem, conventionally, a 2D-interpolation technique has been used to properly interpolate even an unsaved input. The 2D-interpolation method is a method of performing linear interpolation of stored data according to two input parameter values, and can generate appropriate output data even for input parameter values between data.

On the other hand, each data stored in the lookup table basically has an address value accordingly. Since these address values generally have integer values, it is common for the data to be stored to store the value of a condition corresponding to an integer magnification of a fixed unit value.

However, if the data on the torque is stored in multiples of each unit value, there is little possibility that the experimentally measured maximum torque value is stored in multiples of the unit torque value. In particular, when torque control is performed in the weak magnetic flux driving region, the maximum torque value in the constant torque region and the maximum torque of the weak magnetic flux driving region are inevitably different. Due to this cause, an interpolation error may occur between the torque command and the output torque when the 2D interpolation method is applied to the input parameter in the maximum torque output data section.

Conventionally, in order to solve this problem, the torque command capable of input processing is limited to a portion in which torque data is stored as an integer multiple, but this has a problem of reducing the motor output.

It is an object of at least one embodiment of the present invention to provide a maximum torque control error compensation method and apparatus for improving linear interpolation error of final output data generated when a permanent magnet synchronous motor based on a lookup table is driven. Further, the present invention provides a computer-readable recording medium having recorded thereon a program for executing the method on a computer. The technical problem to be achieved by the method and apparatus for compensating the maximum torque control error in the permanent magnet synchronous motor is not limited to the above technical problems, and other technical problems may exist.

According to an embodiment, a control method of a permanent magnet synchronous motor (PMSM) may include receiving a speed and torque command of a rotor of the permanent magnet synchronous motor; Obtaining dq-axis current values corresponding to the speed and torque command of the rotor using a lookup table relating to motor current values; Compensating for an error of the maximum output torque by using the maximum output torque table for each speed; And interpolating the dq-axis current values using the compensated maximum output torque.

Acquiring the dq-axis current values may include acquiring first data and second data corresponding to each of the rotor speed and the torque command; And acquiring dq-axis current values corresponding to each of the first data and the second data using a lookup table for the motor current values.

The first data may include rounding data of an input value and the second data may include rounding data of an input value.

Compensating for the error of the maximum output torque may include obtaining first data and second data corresponding to each of the rotor speed and the torque command; Determining whether the torque command is included in the maximum output torque error generation region based on the speed of the rotor and the torque command; Obtaining a maximum output torque corresponding to the speed of the rotor based on the maximum output torque table for each speed when included in the maximum output torque error generation region; Calculating an error between the first data corresponding to the torque command and the maximum output torque; And compensating for an error between the first data corresponding to the torque command and the maximum output torque to obtain third data.

Determining whether the torque command is included in the maximum output torque error generation region may include determining whether second data corresponding to the speed of the rotor is equal to or greater than a predetermined speed; And determining whether the first data corresponding to the torque command and the second data corresponding to the torque command are included in a predetermined range.

The predetermined speed may include a rated speed.

The interpolating of the current values may include first interpolating the dq-axis current values corresponding to the second data corresponding to the speed of the rotor and the third data, respectively; And performing secondary interpolation on the first interpolation result.

The interpolating of the current values may include: first interpolating the dq-axis current values corresponding to the first data corresponding to the torque command and the second data, respectively; And performing secondary interpolation on the first interpolation result.

The interpolating of the current values may include dq-axis current values corresponding to each of the first data and the second data using a lookup table for the motor current values when the current value is not included in the maximum output torque error generation region. Obtaining; Firstly interpolating the dq-axis current value corresponding to each of first data corresponding to the speed of the rotor and second data corresponding to the speed of the rotor; And performing secondary interpolation on the first interpolation result.

The look-up table stores dq-axis current values corresponding to an integral multiple of unit speed and unit torque of a predetermined size, and the speed and torque command of the rotor are determined by dividing the unit speed and the unit torque, respectively. Can be.

The maximum output torque table for each speed may store maximum output torque values corresponding to an integral multiple of the unit speed.

According to an embodiment, the permanent magnet synchronous motor control apparatus includes a lookup table including dq-axis current values corresponding to integral multiples of unit speed and unit torque, and a maximum output torque value corresponding to integer multiples of the unit speed. A memory for storing an output torque table; And receiving the speed and torque command of the rotor, acquiring dq-axis current values corresponding to the speed and torque command of the rotor using the look-up table, and using the maximum output torque table to determine the maximum output torque. And a processor that compensates for errors and interpolates the dq-axis current values using the compensated maximum output torque.

The processor acquires first data and second data corresponding to each of the speed and torque command of the rotor, and the torque command is set to a maximum output torque error generation area based on the speed and torque command of the rotor. If it is included in the maximum output torque error generation area, the maximum output torque corresponding to the speed of the rotor is obtained based on the maximum output torque table for each speed, and the first data corresponding to the torque command is determined. And an error between the maximum output torque and the third output, by compensating for an error between the first data corresponding to the torque command and the maximum output torque.

According to an embodiment of the present disclosure, a method and apparatus for compensating for maximum torque control error for improving linear interpolation error of final output data generated when a permanent magnet synchronous motor based on a lookup table is driven may be provided. In detail, the error of the maximum output torque may be compensated for by using the maximum output torque table for each speed. Thereby, the precision of the torque control of a permanent magnet synchronous motor can be improved.

1 is a diagram illustrating a driving method of a permanent magnet synchronous motor based on a lookup table according to an exemplary embodiment.
2 is a diagram for explaining an interpolation method, according to an exemplary embodiment.
3 is a graph illustrating the d-axis current value and q-axis current value for the speed and torque of the rotor according to an embodiment.
4 is a graph illustrating a method of obtaining a d-axis current value and a q-axis current value using 2D-interpolation according to an embodiment.
5 is a graph illustrating an error occurrence of the maximum output torque according to an embodiment.
6 is a graph illustrating an error between an actual maximum output torque in a field weakening area and a maximum output torque stored in a lookup table, according to an exemplary embodiment.
7 is a flowchart illustrating a conventional 2D-interpolation method according to an embodiment.
8 is a graph for describing a method of obtaining a d-axis current value and a q-axis current value by using a 2D interpolation method through a permanent magnet synchronous motor control method according to an embodiment.
9 is a flowchart for explaining a modified 2D-interpolation method for correcting torque control error of final output data.
10A is a graph showing torque control error when a conventional 2D interpolation method is used in a field weakening driving area of 3000 rpm.
10B is a graph illustrating a result of performing torque control through the permanent magnet synchronous motor control method according to an exemplary embodiment.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, various changes may be made to the embodiments so that the scope of the patent application is not limited or limited by these embodiments. It is to be understood that all changes, equivalents, and substitutes for the embodiments are included in the scope of rights.

The terminology used herein is for the purpose of description and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

In addition, in the description with reference to the accompanying drawings, the same components will be given the same reference numerals regardless of the reference numerals and duplicate description thereof will be omitted. In the following description of the embodiment, if it is determined that the detailed description of the related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

1 is a view illustrating a method of driving a lookup table-based permanent magnet synchronous motor according to an embodiment.

Permanent Magnet Synchronous Motor (PMSM) operates by generating a magnetic flux using a permanent magnet located in the rotor of a permanent magnet synchronous motor and applying current to the stator using the generated magnetic flux. do. The permanent magnet synchronous motor according to an embodiment may be an embedded permanent magnet synchronous motor (IPMSM), but is not limited thereto.

Referring to FIG. 1, the permanent magnet synchronous motor includes a 2D lookup table 110, a d-axis current controller 115, a q-axis current controller 120, a coordinate inverse converter 125, a pulse width modulator 130, and an inverter. It may include a 135, a synchronous motor 140, a position sensor 145, and a coordinate converter 150.

The permanent magnet synchronous motor shown in FIG. 1 shows only the components related to this embodiment in order to prevent the features of this embodiment from being blurred. Those skilled in the art can understand that other general purpose components may be further included in addition to the components shown in FIG. 1.

The permanent magnet synchronous motor driving system may store and drive appropriate data in the lookup table 110 according to a control input for a user or an environment change. The motor control technique using a lookup table is generally used for vehicle motor control because it can reflect experimental data and has high reliability because it does not affect the control dynamics.

The lookup table 110 may receive the current speed w _r and the torque command of the rotor obtained by differentiating data sensed by the position sensor 145. Torque command can mean the value of torque to output.

2 is a diagram for describing an interpolation method, according to an exemplary embodiment.

The data of the lookup table according to an embodiment has discontinuous data for a specific speed and torque command. Since it is impossible to store data suitable for all speed-torque commands, 2D-interpolation can be applied for each speed and torque command.

Interpolation may be a method of estimating parts of data that are not present in the data. Linear interpolation may be a method of obtaining a function value of an arbitrary point between two points on a vertical line.

Linear interpolation can be represented by Equation 1.

Where f (x) is the interpolated output, x ₂ and x ₁ are rounded up and down values for the input parameters, f (x ₂ ) and f (x ₁ ) are rounded up and stored data values according to the rounded down parameters, And x is an input parameter value. Since the division operation on the variable is a burden on the operation of the microprocessor, when it is treated as a fixed value (x _unit ), Equation 1 may be modified as in Equation 2.

The 2D interpolation method may be an interpolation method in which linear interpolation in one dimension is extended to two dimensions. See FIGS. 2 through 4 for details of the 2D-interpolation method.

)과 회전자의 현재 속도(w_r)가 입력될 수 있다. 회전자의 현재 속도와 토크지령이 입력되면, 룩업 테이블에 단위토크, 단위속도에 따라 저장되어 있는 값들 중에 입력된 파라미터에 대한 제1 데이터와 제2 데이터에 대응하는 dq축 전류 값들을 획득할 수 있다. Referring to FIG. 2, the torque command (see the lookup table 210)

) And the current speed w _r of the rotor can be entered. When the current speed and torque command of the rotor are input, the dq-axis current values corresponding to the first data and the second data of the input parameters among the values stored according to the unit torque and the unit speed in the lookup table can be obtained. have.

,

,

,

)을 획득할 수 있다.According to an embodiment, the first data may be rounding data of an input value and the second data may be rounding data of an input value. For example, when the current speed and torque command of the former are inputted, dq-axis current values corresponding to the raised data and the lowered data of the input parameter among the values stored according to the unit speed in the lookup table (

,

,

,

) Can be obtained.

,

)을 얻을 수 있다. 반대로, 토크에 대한 선형 보간을 수행한 후 얻은 두 개의 결과값을 회전자의 속도에 대해 선형 보간하여도 동일하게 최종보간 된 dq축 전류지령(

,

)을 얻을 수 있다.In the interpolator 220, 2D-interpolation may be applied to dq-axis current values obtained by using the lookup table 210. If linear interpolation is performed on the two results obtained after performing linear interpolation on the rotor speed, the final interpolated dq-axis current command (

,

) Can be obtained. On the contrary, even if the two result values obtained after performing linear interpolation for torque are linearly interpolated with respect to the rotor speed, the final interpolated dq-axis current command (

,

) Can be obtained.

3 is a graph illustrating a d-axis current value and a q-axis current value for the speed and torque of the rotor according to an embodiment.

Referring to FIG. 3, the d-axis current value and the q-axis current in the look-up table are only applicable to six black points according to the combination of the rotor speeds w ₁ , w ₂ and torque commands T ₁ , T ₂ , and T ₃ . The value can be stored.

If the value of the received speed is a value that does not exist in the list on the lookup table such as w ₁ , w _2, and the torque command is a value that does not exist in the list on the lookup table such as T ₁ , T ₂ , T ₃ By using the interpolation method, the d-axis current value and the q-axis current value can be obtained.

4 is a graph illustrating a method of obtaining a d-axis current value and a q-axis current value using 2D-interpolation according to an embodiment.

)과 회전자의 현재 속도(w_r)가 입력되면, 룩업 테이블에 단위토크, 단위속도에 따라 저장되어 있는 값들 중에 입력된 파라미터에 대한 올림 데이터와 내림 데이터를 출력할 수 있다. 올림 데이터는 아랫 첨자기호 max로, 내림 데이터는 아랫 첨자기호 min으로 구분할 수 있다. 예를 들어, 회전자의 현재 속도(w_r)의 내림 데이터는 w_min, 회전자의 현재 속도(w_r)의 올림 데이터는 w_max일 수 있다. 마찬가지로 토크지령(

)의 내림 데이터는 T_min, 토크지령(

)의 올림 데이터는 T_max일 수 있다.Referring to Figure 4, torque command (

) And the current speed (w _r ) of the rotor are input, the rounding data and the rounding data for the input parameter among the values stored according to the unit torque and the unit speed in the lookup table can be output. Rounding data can be classified by the subscript max, and rounding data by the subscript min. For example, raising the data of down data, w _min, the current speed (w _r) of the rotor of the current speed (w _r) of the rotor may be a w _max. Similarly, torque command (

), The down data is T _min , torque command (

The rounding data of) may be T _max .

Since two inputs of speed and torque are outputted up and down data, four data can be obtained, which can be represented by the black dots 410, 420, 430, and 440 of FIG. 4.

)을 얻을 수 있다. 반대로, 토크에 대한 선형 보간을 수행한 후 얻은 두 개의 결과값을 회전자의 속도에 대해 선형 보간하여도 동일하게 최종보간 된 dq축 전류지령(

)을 얻을 수 있다.When linear interpolation is performed on two torques (450, 460) obtained after performing linear interpolation on the speed of the rotor, the final interpolated dq-axis current command (

) Can be obtained. On the contrary, even if the two result values obtained after performing linear interpolation for torque are linearly interpolated with respect to the rotor speed, the final interpolated dq-axis current command (

) Can be obtained.

)은 수학식 3과 같이 표현할 수 있다.Last interpolated dq axis current command

) Can be expressed as in Equation 3.

Looking at Equation 3, the current data stored in the lookup table should be applied according to the multiple of the torque command. In order to obtain the maximum torque output according to the torque command, the unit torque of Equation 3 should be set as in Equation 4.

는 최대토크 출력, k_max는 토크축 최대 허용 메모리 수를 나타낼 수 있다.

Is the maximum torque output and k _max may represent the maximum allowable number of memories in the torque axis.

Conventionally, when generating dq-axis current command as a compensation method for such discontinuous data, current output is compensated by using linear interpolation technique for input condition of lookup table, but in case of 2D-lookup table, unit torque Since the data is stored, it may be difficult to reflect the maximum output torque data that varies with each speed in a specific area. In this regard, see FIG. 5 for details.

5 is a graph illustrating an error occurrence of a maximum output torque according to an exemplary embodiment.

The induced electromotive force generated during the rotation of the permanent magnet synchronous motor is generated in a direction that hinders the rotation of the rotor, which is called counter electromotive force. The counter electromotive force is proportional to the rotation time change of the rotor. Therefore, when the permanent magnet synchronous motor rotates at a low speed, it is less generated and does not have a great influence on the motor control. It increases in proportion to the speed. This large generated back EMF may not be able to obtain the desired motor output speed or output from the input voltage / current. When the motor's rated speed is exceeded, the output voltage reaches its limit and no longer increases, and it can reach the field weakening area that does not guarantee constant torque. The maximum output torque for each speed may be predetermined according to the characteristics of the permanent magnet synchronous motor. In the field weakening area, the maximum output torque can be inversely proportional to the speed of the rotor. An area other than the field weakening area may be referred to as a static torque area.

Referring to FIG. 5, the maximum output torque in the constant torque region does not change according to the speed of the rotor, but in the weak field region, the maximum output torque may decrease as the speed of the rotor increases.

The maximum output torque in the constant torque range can be obtained to match the torque command, but since the maximum output torque decreases as the rotor speed increases in the field weakening area, the maximum output torque in the field weakening area is the unit torque. May not match the integer multiple of.

Table 1 may be a lookup table that stores the d-axis current value according to unit torque 7.948 [Nm] and unit speed 500 [rpm].

0 500 1000 1500 2000 2500 3000 3500 4000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.95 -8.24 -8.24 -8.24 -8.24 -8.24 -8.24 -8.24 -8.24 -8.24 15.90 -21.31 -21.31 -21.31 -21.31 -21.31 -21.31 -21.31 -21.31 -21.31 23.84 -33.54 -33.54 -33.54 -33.54 -33.54 -33.54 -33.54 -33.54 -39.17 31.79 -44.60 -44.60 -44.60 -44.60 -44.60 -44.60 -44.60 -49.12 -65.55 39.74 -54.69 -54.69 -54.69 -54.69 -54.69 -54.69 -54.69 -73.24 -91.93 47.69 -64.00 -64.00 -64.00 -64.00 -64.00 -64.00 -74.82 -97.47 -119.31 55.63 -72.68 -72.68 -72.68 -72.68 -72.68 -72.68 -96.40 -122.48 -144.66 63.58 -80.83 -80.83 -80.83 -80.83 -80.83 -87.99 -118.40 -139.66 -144.66 71.53 -88.53 -88.53 -88.53 -88.53 -88.53 -106.67 -131.62 -139.66 -144.66 79.48 -95.86 -95.86 -95.86 -95.86 -95.86 -117.26 -131.62 -139.66 -144.66

The torque stored in the lookup table and the speed of the rotor may be the input torque command, the raising data and the lowering data of the current speed of the rotor. Referring to Table 1, the maximum output torque is 79.48 Nm until the rotor speed is 2000 rpm. It can be seen that the same. The maximum output torque in this area can obtain a value (79.48 Nm) corresponding to the maximum output torque of the lookup table.

After the rotor speed is 2500rpm, the maximum output torque decreases as the rotor speed increases, indicating that this area is the field weakening area. It is possible to determine the weak field by looking at the current speed of the input rotor.

According to an embodiment, when the falling data of the current speed of the input rotor is greater than or equal to the predetermined speed, the weak field may be determined. For example, when the current speed of the input rotor is 2750 rpm, the down data may be 2500 rpm. Since the region where the speed of the rotor is 2500 rpm or later can be determined as the field weakening area, it can be determined as the field weakening area in this case.

It can be seen that the maximum output torque is output even when a torque command of more than the maximum output torque is input. Torque commands above the maximum output torque may be meaningless.

Since the maximum output torque decreases as the rotor speed increases in the field weakening area, the maximum output torque in the field weakening area may not coincide with the integral multiple of the unit torque. For example, if the speed of the rotor is 3000 rpm, the maximum output torque may be any value between 63.58 Nm and 71.53 Nm, not exactly 71.53 Nm. Since the lookup table contains only the information about the integral multiple of the unit torque, accurate information about the maximum output torque in the field weakening area cannot be known.

Since the lookup table does not include accurate information about the maximum output torque in the field weakening area, an error may occur when interpolation using the torque value stored in the lookup table. Specifically, since a torque command of more than the maximum output torque is meaningless, an error may occur when the raised data of the torque command exceeds the maximum output torque and the lowered data of the torque command is less than or equal to the maximum output torque in the field weakening area. The area where such an error occurs may be referred to as a maximum output torque error generating area. An error may occur as much as the difference between the raised data of the torque command and the actual maximum output torque.

For example, when the speed of the current rotor is 3000rpm, the maximum output torque may be 68.34Nm. Since 68.34 Nm is not an integer multiple of unit torque, it may not be stored in the lookup table. In this case, the interpolation may be performed based on 71.53Nm instead of 68.34Nm. An error may occur because the interpolation is performed using the nearest value among the integer multiples of the unit torque rather than the actual value. 6 shows this error in more detail.

6 is a graph illustrating an error between the actual maximum output torque and the maximum output torque stored in the lookup table in the maximum output torque error generation area, according to an exemplary embodiment.

이지만, 실제 출력은 약계자 영역에서의 특정 속도의 최대출력 토크를 출력하기 때문에, 출력토크는 입력 토크지령 대비

의 토크제어오차가 나타날 수 있다. 표 1의 값을 예를 들면, 현재 회전자의 속도가 3000rpm, 입력 토크지령은 단위토크에 대한 정수배인 9*7.948Nm(71.53Nm)이지만, 실제 출력은 68.34Nm 로, 출력토크는 입력 토크지령 대비 9*7.948Nm - 68.34Nm인 3.19Nm일 수 있다.Referring to FIG. 6, an error between the actual maximum output torque and the maximum output torque stored in the lookup table may occur in the maximum output torque error generation region. The input torque command is an integer multiple of the unit torque

However, since the actual output outputs the maximum output torque of a certain speed in the field weakening area, the output torque is compared with the input torque command.

Torque control error may appear. Taking the value of Table 1 as an example, the current rotor speed is 3000rpm and the input torque command is 9 * 7.948Nm (71.53Nm), which is an integral multiple of the unit torque, but the actual output is 68.34Nm and the output torque is the input torque command. It can be 3.19Nm, which is 9 * 7.948Nm-68.34Nm in contrast.

7 is a flowchart illustrating a conventional 2D-interpolation method according to an embodiment.

Referring to FIG. 7, in the conventional 2D interpolation method, steps of receiving a torque command and a current speed of a rotor (710 and 715), converting input data into unit values (720 and 725), and converting into unit values Step (730, 735, 740, 745) of decimal point rounding of one data, extracting the current map data using the decimal point rounding, rounding data (750), applying a unit torque interpolation formula to the descending speed data Step 755, applying the unit torque interpolation formula to the rounding speed data (760), applying the interpolation formula for the unit speed (765), and obtaining the dq-axis current command (770.775) It may include. The application of the interpolation method for the speed and the interpolation method for the torque can be applied interchangeably to obtain consistent data.

In the conventional 2D interpolation method, an error may not exist in the constant torque region, but a maximum output torque error generation region may exist. In order to compensate for the above error, a maximum output torque map according to an embodiment may be used.

A control method of a permanent magnet synchronous motor according to an embodiment includes receiving a speed and torque command of a rotor of a permanent magnet synchronous motor, and responding to the speed and torque command of the rotor using a look-up table for motor current values. Obtaining dq-axis current values. Acquire the first data and the second data corresponding to each of the speed and torque commands of the rotor using the lookup table, and the dq axis corresponding to each of the first and second data using the lookup table related to the motor current values. Current values can be obtained.

The first data may include rounding data of the input value and the second data may include rounding data of the input value.

The control method of the permanent magnet synchronous motor includes compensating for an error of the maximum output torque by using the maximum output torque table for each speed. The maximum output torque table may be a table in which the maximum output torque data for each speed of the rotor is stored in advance. For example, the maximum output torque table may store a maximum output torque 68.34 Nm corresponding to the speed 3000 rpm of the rotor.

Compensating the error of the maximum output torque may include determining whether the torque command is included in the maximum output torque error generation region based on the speed and torque command of the rotor. The error may not occur when the maximum output torque error is not generated.

In the case of determining that it is included in the maximum output torque error generation region, the maximum output torque corresponding to the speed of the rotor may be obtained based on the maximum output torque table for each speed. When the actual maximum output torque corresponding to the speed of the rotor is obtained, an error between the first data corresponding to the torque command and the maximum output torque can be calculated. The third data may be obtained by compensating for the above error.

Determining whether the torque command is included in the maximum output torque error generation region includes determining whether the second data corresponding to the speed of the rotor is equal to or greater than a predetermined speed, and the first data and the second data corresponding to the torque command The method may include determining whether it is included in a predetermined range. For example, the maximum output torque error generation region may be a region in which the up data of the torque command exceeds the maximum output torque and the down data of the torque command is less than or equal to the maximum output torque in the field weakening area. If the falling data of the current speed of the input rotor is greater than or equal to the predetermined speed, it may be determined as the field weakening area.

According to an embodiment, the maximum output torque error generation region obtained by the above step may be stored in advance in the memory address value. When the data is input, the memory address value information stored in advance may determine whether the data is included in the maximum output torque error generation region.

The dq-axis current values may be interpolated using the compensated maximum output torque. Since the error between the first data corresponding to the torque command and the maximum output torque is compensated for using the maximum output torque table, more accurate interpolation may be possible.

First, the dq-axis current value corresponding to each of the second data corresponding to the speed of the rotor, the first data corresponding to the torque command and the third data compensated for the error of the maximum output torque may be interpolated. More accurate dq-axis current command can be obtained through the second interpolation with respect to the first interpolation result. On the contrary, even if the linear interpolation of two results obtained after performing linear interpolation for torque is performed on the speed of the rotor, the same final interpolated dq-axis current command can be obtained.

When not included in the maximum output torque error generation region, the dq-axis current command can be obtained according to the existing 2D interpolation method as shown in FIG. 7. Dq-axis current values corresponding to each of the first and second data are obtained using a look-up table relating to the motor current values, and dq-axis corresponding to the first and second data corresponding to the speed of the rotor, respectively. The dq-axis current command may be obtained by first interpolating the current value and performing second interpolation on the first interpolation result.

FIG. 8 is a graph illustrating a method of obtaining a d-axis current value and a q-axis current value by using a 2D interpolation method through a permanent magnet synchronous motor control method according to an exemplary embodiment.

Referring to FIG. 8, FIG. 8 illustrates a maximum output torque error generation region. Unlike FIG. 4, it can be seen that the raising data of the torque command changes with speed.

Taking Table 1 as an example, the input data may be 2750 rpm and 67.558 Nm. The first data and the second data of the current speed of the input rotor may be 3000 rpm and 2500 rpm, respectively, and the first data and the second data of the torque command may be 71.53 Nm and 63.58 Nm, respectively.

The first data and the second data of the input data may be used to determine whether the maximum output torque error occurs. Since the second data of the current speed of the input rotor is more than a predetermined speed (rated speed) at 2500 rpm, it can be determined that it corresponds to the field weakening area. In the case of the first data (3000 rpm) of the current speed of the rotor, the maximum output torque is increased because 71.53 Nm of the torque command is greater than the maximum output torque of 68.34 Nm and 63.58 Nm of the torque command is less than or equal to the maximum output torque of 68.34 Nm. It can be determined as an error occurrence area. In the case of the second data (2500 rpm) of the current speed of the rotor, it can be determined that the raised data 71.53 Nm of the torque command is not the maximum output torque error generation region because it is smaller than the maximum output torque.

Since the maximum output torque error is generated, the error between the first data and the maximum output torque corresponding to the torque command can be calculated. In this case, the error may be 3.19 Nm, which is 71.53 Nm-68.34 Nm. By compensating for the above error, 68.34 Nm may be determined as the third data.

Finally, four data can be obtained, which can be points 810 (2500 rpm, 63.58 Nm), 820 (3000 rpm, 63.58 Nm), 830 (2500 rpm, 71.53 Nm), and 840 (3000 rpm, 68.34 Nm). 4, the torque values of points 430 and 440 are the same in FIG. 4, but the torque values of points 830 and 840 are different in FIG. 8. It can be seen that the error is compensated by reflecting the change in torque value according to the speed in the field weakening area.

9 is a flowchart for explaining a modified 2D-interpolation method for correcting torque control error of final output data.

Referring to FIG. 9, the modified 2D interpolation method for correcting the torque control error of the final output data is a step of checking the maximum output torque error generation region and changing the maximum output torque data to the existing 2D interpolation method. To that end, we added a step 965 to table the maximum output torque data for each speed.

Taking Table 1 as an example, the input data may be referred to as 2750 rpm (915) and 67.558 Nm (910). When the input data is divided up into unit values (920 and 925) and rounded up and down, the input data may be 9 (930), 8 (935), 6 (940), and 5 (945). In operation 950, current map data may be extracted from the lookup table. Based on this, it can be checked whether the maximum output torque error generation area is present (955). The area of maximum output torque error occurrence can be determined by dividing the unit torque into memory address value information that has been raised or lowered by the decimal point.

The maximum output unit torque change value for each speed may be calculated using the maximum output torque table 965 (960). The maximum output torque table 965 may store maximum output torque values corresponding to integer multiples of the same unit speed as the lookup table. When the rotor speed is 3000rpm, the maximum output torque may be 68.34 Nm, unit torque is 7.948 Nm, and unit torque change value is 8.6 (960).

Dq-axis current values corresponding to four points ((5, 8), (6, 8), (5, 9), (5, 9)) obtained using the lookup table. 5, 8.6) can be interpolated for four points ((5, 8), (6, 8), (5, 9), and (5, 8.6) that are error compensated.

FIG. 10A is a graph illustrating torque control error when a conventional 2D interpolation method is used in a field weakening driving area of 3000 rpm.

Referring to FIG. 10A, to obtain a torque output of 68.34 Nm, which is the maximum torque of 3000 rpm, 71.53 Nm should be applied as the torque command, and it can be seen that an interpolation error exists from 63.58 Nm, the maximum output torque range, to the maximum output torque. .

10B is a graph illustrating a result of performing torque control through the permanent magnet synchronous motor control method according to an exemplary embodiment.

Referring to FIG. 10B, it can be seen that, unlike FIG. 10A, a control error does not occur, and when a command greater than the maximum output torque is applied, a maximum torque that can be output at 3000 rpm appears.

A permanent magnet synchronous motor control apparatus according to an embodiment includes a lookup table storing dq-axis current values corresponding to an integral multiple of unit speed and unit torque, and a maximum output storing maximum output torque values corresponding to an integral multiple of unit speed. The torque table, the speed and torque command of the rotor are input, the dq-axis current values corresponding to the speed and torque command of the rotor are obtained using the lookup table, and the error of the maximum output torque is obtained using the maximum output torque table. And a processor for compensating and interpolating dq-axis current values using the compensated maximum output torque.

The processor obtains first data and second data corresponding to each of the rotor speed and torque command, and determines whether the torque command is included in the maximum output torque error generation region based on the speed and torque command of the rotor. When included in the output torque error generation area, the maximum output torque corresponding to the speed of the rotor is obtained based on the maximum output torque table for each speed, and the error between the first data and the maximum output torque corresponding to the torque command is calculated. The third data may be obtained by compensating for an error between the first data corresponding to the torque command and the maximum output torque.

The embodiments described above may be implemented as hardware components, software components, and / or combinations of hardware components and software components. For example, the devices, methods, and components described in the embodiments may include, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors, microcomputers, field programmable gates (FPGAs). It may be implemented using one or more general purpose or special purpose computers, such as an array, a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of explanation, one processing device may be described as being used, but one of ordinary skill in the art will appreciate that the processing device includes a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as parallel processors.

The software may include a computer program, code, instructions, or a combination of one or more of the above, and may configure the processing device to operate as desired, or process independently or collectively. You can command the device. Software and / or data may be any type of machine, component, physical device, virtual equipment, computer storage medium or device in order to be interpreted by or to provide instructions or data to the processing device. Or may be permanently or temporarily embodied in a signal wave to be transmitted. The software may be distributed over networked computer systems so that they may be stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described with reference to the accompanying drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or, even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (14)

In the control method of a permanent magnet synchronous motor (PMSM),
Receiving a speed and torque command of the rotor of the permanent magnet synchronous motor;
Obtaining dq-axis current values corresponding to the speed and torque command of the rotor using a lookup table relating to motor current values;
Compensating for an error of the maximum output torque by using the maximum output torque table for each speed; And
Interpolating the dq-axis current values using the compensated maximum output torque
Permanent magnet synchronous motor control method comprising a.
The method of claim 1,
Acquiring the dq-axis current values
Acquiring first data and second data corresponding to each of the rotor speed and the torque command; And
Obtaining dq-axis current values corresponding to each of the first data and the second data using a look-up table relating to the motor current values
Permanent magnet synchronous motor control method comprising a.
The method of claim 2,
And the first data is rounding data of the input value and the second data is rounding data of the input value.
The method of claim 1,
Compensating the error of the maximum output torque
Acquiring first data and second data corresponding to each of the rotor speed and the torque command;
Determining whether the torque command is included in the maximum output torque error generation region based on the speed of the rotor and the torque command;
Obtaining a maximum output torque corresponding to the speed of the rotor based on the maximum output torque table for each speed when included in the maximum output torque error generation region;
Calculating an error between the first data corresponding to the torque command and the maximum output torque; And
Compensating for an error between the first data corresponding to the torque command and the maximum output torque to obtain third data;
Permanent magnet synchronous motor control method comprising a.
The method of claim 4, wherein
The step of determining whether the torque command is included in the maximum output torque error generation region is
Determining whether second data corresponding to the speed of the rotor is equal to or greater than a predetermined speed; And
Determining whether the first data corresponding to the torque command and the second data corresponding to the torque command are included in a predetermined range.
Permanent magnet synchronous motor control method comprising a.
The method of claim 5,
The predetermined speed is a permanent magnet synchronous motor control method comprising a rated speed.
The method of claim 4, wherein
Interpolating the current values
Firstly interpolating second data corresponding to the speed of the rotor and the dq-axis current value corresponding to each of the third data; And
Quadratic interpolation for the first interpolation result
Permanent magnet synchronous motor control method comprising a.
The method of claim 4, wherein
Interpolating the current values
Firstly interpolating the dq-axis current value corresponding to each of the first data and the second data corresponding to the torque command; And
Quadratic interpolation for the first interpolation result
Permanent magnet synchronous motor control method comprising a.
The method of claim 4, wherein
Interpolating the current values
Acquiring dq-axis current values corresponding to each of the first data and the second data using a look-up table for the motor current values when not included in the maximum output torque error generation region;
Firstly interpolating the dq-axis current value corresponding to each of first data corresponding to the speed of the rotor and second data corresponding to the speed of the rotor; And
Quadratic interpolation for the first interpolation result
Permanent magnet synchronous motor control method comprising a.
The method according to any one of claims 1 to 9,
The lookup table stores dq-axis current values corresponding to an integral multiple of a unit speed and unit torque of a predetermined size.
And a speed command and the torque command of the rotor are determined by dividing the unit speed and the unit torque, respectively.
The method of claim 10,
The maximum output torque table for each speed stores the maximum output torque values corresponding to an integral multiple of the unit speed, permanent magnet synchronous motor control method.
A computer program stored in a recording medium in combination with hardware to execute the method of any one of claims 1 to 9.
A memory for storing a lookup table including dq-axis current values corresponding to integral multiples of unit speed and unit torque, and a maximum output torque table including maximum output torque values corresponding to integer multiples of the unit speed; And
Receives the speed and torque command of the rotor, obtains dq-axis current values corresponding to the speed and torque command of the rotor using the lookup table, and the error of the maximum output torque using the maximum output torque table. And interpolating the dq-axis current values using the compensated maximum output torque.
Permanent magnet synchronous motor control device comprising a.
The method of claim 13,
The processor is
Acquire first and second data corresponding to each of the speed and torque command of the rotor, and determine whether the torque command is included in the maximum output torque error generation region based on the speed and torque command of the rotor. When included in the maximum output torque error generation area, the maximum output torque corresponding to the speed of the rotor is obtained based on the maximum output torque table for each speed, and the first data corresponding to the torque command and the maximum Calculating an error between the output torque and compensating for an error between the first data corresponding to the torque command and the maximum output torque to obtain third data;
Permanent magnet synchronous motor control device.

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