KR101693424B1 - Apparatus for controlling motor - Google Patents

Apparatus for controlling motor Download PDF

Info

Publication number
KR101693424B1
KR101693424B1 KR1020150072953A KR20150072953A KR101693424B1 KR 101693424 B1 KR101693424 B1 KR 101693424B1 KR 1020150072953 A KR1020150072953 A KR 1020150072953A KR 20150072953 A KR20150072953 A KR 20150072953A KR 101693424 B1 KR101693424 B1 KR 101693424B1
Authority
KR
South Korea
Prior art keywords
stator current
current value
torque
target torque
axis
Prior art date
Application number
KR1020150072953A
Other languages
Korean (ko)
Other versions
KR20160139104A (en
Inventor
이은우
Original Assignee
엘에스산전 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘에스산전 주식회사 filed Critical 엘에스산전 주식회사
Priority to KR1020150072953A priority Critical patent/KR101693424B1/en
Publication of KR20160139104A publication Critical patent/KR20160139104A/en
Application granted granted Critical
Publication of KR101693424B1 publication Critical patent/KR101693424B1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage

Abstract

The present invention relates to an electric motor control device. An electric motor control apparatus according to an embodiment of the present invention includes an input unit for receiving a target torque and a control unit for setting an initial stator current value and for generating the target torque based on the initial stator current value and a predetermined target torque error value And a controller for calculating a minimum stator current value and calculating a D axis current command and a Q axis current command for generating the target torque using the minimum stator current value. According to the present invention, when the target torque of the electric motor is given, the magnitude of the stator current required to generate the target torque and accordingly the D-axis current command and the Q-axis current command are more accurately determined, There are advantages.

Description

[0001] APPARATUS FOR CONTROLLING MOTOR [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor control apparatus, and more particularly, to a control apparatus for an MTPA operation of an Interior Permanent Magnet Synchronous Machine (IPMSM).

The permanent magnet type synchronous motor is advantageous in that the output torque per unit volume is larger than that of the induction motor and the efficiency is excellent. However, there is a disadvantage that the permanent magnet used in the permanent magnet type synchronous motor is expensive, and that the inverter is used because it can not be operated by directly turning on the commercial power source. However, there is no need to add an additional inverter when the inverter is already used for the induction motor operation. Recently, as the price of the permanent magnet has been decreasing, a permanent magnet type synchronous motor .

The permanent magnet type synchronous motor is divided into a surface mount type permanent magnet synchronous motor and a recessed permanent magnet synchronous motor depending on the position of the permanent magnet in the rotor. In the case of embedded permanent magnet synchronous motor (IPMSM), it is possible to use the reluctance torque generated by the difference of the inductance of the D axis and the Q axis in addition to the magnetic torque. When the reluctance torque is used, Can be generated. At this time, the method of distributing the same stator current to the D axis current and the Q axis current appropriately to generate the maximum torque is called MTPA (Maximum Torque Per Ampere).

As a method for MTPA operation, that is, maximum torque operation per unit current, there is a method of storing D and Q axis current command in advance in the experiment, but there is a problem that the user can not perform such experiment in actual field. Therefore, in practice, there is a need for a method that can implement the MTPA operation in an approximate manner using only the D-axis and Q-axis inductances that the user can recognize in advance. In particular, given the target torque to be obtained through the motor, it is possible to operate the MTPA more easily if the D-axis current command and the Q-axis current command necessary for generating the target torque can be obtained. Meanwhile, Korean Patent Publication No. 10-2013-0138999 discloses a prior art related to the present invention.

The present invention relates to an electric motor control apparatus and a motor control apparatus that more accurately determine the magnitude of a stator current required to generate a target torque and a D axis current command and a Q axis current command according to the target torque when the target torque of the motor is given, And an object of the present invention is to provide a device.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description and more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

An electric motor control apparatus according to an embodiment of the present invention includes an input unit for receiving a target torque and a control unit for setting an initial stator current value and for generating the target torque based on the initial stator current value and a predetermined target torque error value And a controller for calculating a minimum stator current value and calculating a D axis current command and a Q axis current command for generating the target torque using the minimum stator current value.

According to the present invention as described above, when the target torque of the electric motor is given, the magnitude of the stator current required to generate the target torque and accordingly the D-axis current command and the Q-axis current command are more accurately determined, This is an advantage that it becomes possible.

1 is a graph showing the magnitude of a torque that can be generated according to the speed of a recessed permanent magnet synchronous motor (IPMSM).
2 is a graph showing the difference in torque during maximum torque operation of the IPMSM when only magnetic torque is used and when magnetic torque and reluctance torque are used together.
3 shows D-axis current and Q-axis current during MTPA operation of IPMSM.
4 is a graph showing trajectories of D axis current and Q axis current of IPMSM during MTPA operation.
5 is a configuration diagram of a motor control apparatus according to an embodiment of the present invention.
FIG. 6 is a graph showing the relationship between the initial torque error value and the initial stator current value when the target torque error value is set to 0.1 and the initial stator current value is set as a linear function connecting the origin (maximum current and maximum torque) , The initial value is out of the range of the minimum stator current curve and the maximum stator current curve.
7 is a graph showing the relationship between the initial stator current value and the initial stator current value when the target torque error value is set to 0.1 and the initial stator current value is set as a linear function connecting the origin (maximum current and maximum torque) , The initial value is within the range of the minimum stator current curve and the maximum stator current curve.

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same or similar elements.

1 is a graph showing the magnitude of a torque that can be generated according to the speed of a recessed permanent magnet synchronous motor (IPMSM).

As shown in FIG. 1, the torque T e generated in the IPMSM according to the speed ω r of the IPMSM is constantly displayed up to the specific speed a. However, when the speed of the IPMSM becomes higher than the specific speed a torque (T e) is more and more reduced. As the speed of the IPMSM increases above a certain speed, torque limitation occurs because the range of the current that can be controlled by the back electromotive force generated by the permanent magnet of the rotor decreases as the speed increases. In the graph of Fig. 1, the region where the torque T e is constantly shown is defined as the constant torque region 102, and the region where the torque T e is decreased is defined as the weakened field region 104.

In the weak field region 104 where the torque limitation occurs in Fig. 1, it is possible to use a larger torque through weak field operation. Hereinafter, the motor control apparatus according to the present invention will be described by taking the MTPA operation in the constant torque region 102 as an example, but the present invention is applicable to the weak field region 104 as well.

2 is a graph showing the difference in torque during maximum torque operation of the IPMSM when only magnetic torque is used and when magnetic torque and reluctance torque are used together.

The torque used to drive the IPMSM includes the magnetic torque using only the force of the permanent magnet and the reluctance torque generated due to the difference between the inductance of the D axis and the Q axis. 2, when comparing the torque trajectory 202 when using only magnetic torque and the torque trajectory 204 when using both magnetic torque and reluctance torque, it can be seen that the latter 204 can generate much larger torque .

First, the magnetic torque due to the force of the permanent magnet can be expressed by the following equation.

Figure 112015050185111-pat00001

In Equation (1), T e, magnetic means magnetic torque, λ f means flux density [W b] of the rotor of IPMSM, and i q means Q-axis current.

Next, the reluctance torque generated due to the difference in inductance between the D-axis and the Q-axis can be expressed by the following equation.

Figure 112015050185111-pat00002

In Equation (2), T e, reluctance denotes a reluctance torque, L d denotes a D-axis inductance, L q denotes a Q-axis inductance, i d denotes a D-axis current, and i q denotes a Q-axis current.

As a result, the torque of the IPMSM using both the magnetic torque and the reluctance torque can be expressed as follows using Equations (1) and (2).

Figure 112015050185111-pat00003

In Equation (3), T e denotes a torque generated in the IPMSM.

As shown in Equation (3), the torque of the IPMSM is determined by the D-axis current (i d ) and the Q-axis current (i q ). Therefore, in order to generate a desired torque using the IPMSM, the D-axis current (i d ) and the Q-axis current (i q ) must be determined appropriately.

FIG. 3 shows the D axis current and the Q axis current during the MTPA operation of the IPMSM, and FIG. 4 is a graph showing the D axis current and the Q axis current trajectory of the IPMSM during the MTPA operation.

As shown in FIG. 3, during the MTPA operation of the IPMSM, it can be seen that the D-axis current (i d ) and the Q-axis current (i q ) are used to utilize the reluctance torque. 4 shows the current limit curve 402 by the rated current of the inverter and the electric current of the motor, and the voltage limit curves 404 and 406 by the rotor speed, respectively, along with the trajectory of the current at the time of operation of the IPMSM . Where the voltage-limiting curve becomes smaller when rotor speed is smaller (404) than when rotor speed is lower (406). 4, when the torque command curve 408 is given, if the speed of the rotor is large (406), the MTPA operation is impossible due to the voltage limitation condition, and the voltage limitation ellipse 406 and the torque command curve 408 The D-axis current and the Q-axis current are determined.

If the maximum current applied to the stator, that is, the maximum stator current (I s, max ), is given when the IPMSM is operating in the MTPA mode, the maximum torque magnitude generated by the IPMSM when the corresponding maximum stator current is applied . When the maximum stator current is given by I s, max in the MTPA mode, the maximum D axis current (I d, max ) and the maximum Q axis current (I q, max ) As shown in Fig.

Figure 112015050185111-pat00004

Figure 112015050185111-pat00005

The maximum D-axis current I d, max and the maximum Q-axis current I q, max of Equations 4 and 5 are substituted into Equation 3, The maximum torque (T e, max ) generated during the MTPA operation of the IPMSM can be obtained.

Figure 112015050185111-pat00006

If the magnitude of the stator current (I s) given to a specific value, a maximum torque (T e, max) generated during the MTPA operation of IPMSM is [Equation 4] and [Equation 5] The stator current is (I s) (I d ) and the Q-axis current (I q ) calculated by substituting the equation (6) into the equation (6).

However, conversely, it is difficult to find the minimum current to generate the target torque when the magnitude of the torque to be obtained through the IPMSM, that is, the target torque, is given. This is because the torque expression expressed by Equation (6) It is impossible to obtain an inverse function. Accordingly, the present invention proposes a method for more accurately determining the D-axis current command and the Q-axis current command for generating the target torque when the target torque is given during the MTPA operation of the IPMSM.

5 is a configuration diagram of a motor control apparatus according to an embodiment of the present invention.

Referring to FIG. 5, an electric motor controller 502 according to an embodiment of the present invention includes an input unit 504 and a controller 506.

The input unit 504 receives the target torque value set by the external device or the user. The control unit 506 may set an initial stator current value and calculate a minimum stator current value for generating a target torque value input through the input unit 504 based on the initial stator current value and a predetermined target torque error value have. Further, the controller 506 may calculate the D-axis current command and the Q-axis current command for generating the target torque using the calculated minimum stator current value. The process of generating the D-axis current command and the Q-axis current command by the controller 506 will be described in more detail as follows.

If the target torque input by the input unit 504 is defined as T e, ref and the minimum stator current value to be applied to the stator for generating the target torque is defined as I s , the controller 506 satisfies the following equation The minimum stator current value I s can be obtained.

Figure 112015050185111-pat00007

In Equation (7), T e (I s ) means the magnitude of the torque generated by the IPMSM when the stator current value is given as I s , and can be expressed by the following equation.

Figure 112015050185111-pat00008

In one embodiment of the present invention, the stator current magnitude is calculated using the Newton-Raphson method. In order to apply the Newton-Raphson method, the following equation is obtained by differentiating the equation of [Equation 8].

Figure 112015050185111-pat00009

The control unit 506 can calculate the minimum stator current value by substituting the following expression (9) into the following equation (10).

Figure 112015050185111-pat00010

In Equation (10)

Figure 112015050185111-pat00011
Is defined as a target torque error value.

In an embodiment of the present invention, the control unit 506 repeatedly performs the [Expression 10] while increasing the number of iterations (n, n is a natural number) until the target torque error value becomes equal to or less than a preset reference error value calculating I s, n, and determines the I s, n thus calculated as the minimum value of the stator current for generating the target torque.

Corresponding to when at least the stator current (I s) is determined, the control section 506 is at least the stator current (I s) of at least the stator current (I s) are substituted in Equation 4 and Equation 5] Axis current command I d and the Q-axis current command I q , respectively. Accordingly, the D-axis current command I d and the Q-axis current command I q outputted from the controller 506 are input to the inverter to operate the IPMSM in the MTPA mode, and the IPMSM controls the target Torque can be generated.

On the other hand, it is necessary to set the initial stator current value, that is, I s, 0 , in order to calculate I s, n through Equation (10). The greater the difference between the initial stator current value (I s, 0 ) and the finally calculated minimum stator current value (I s, n ), the greater the number of iterations of Equation (10) need.

Accordingly, the controller 506 calculates a minimum stator current value based on a preset target torque error value and a preset number of repetitions, calculates a set range of the initial stator current value, and calculates an initial stator current value . Hereinafter, an exemplary procedure for setting the initial stator current value by the controller 506 will be described with reference to FIGS. 6 and 7. FIG.

In order to set the initial stator current value, the control unit 506 sets the target torque error value in advance and calculates the setting range of the initial stator current value while increasing the number of repetition (n) of [Expression 10].

FIG. 6 is a graph showing the relationship between the initial torque error value and the initial stator current value when the target torque error value is set to 0.1 and the initial stator current value is set as a linear function connecting the origin (maximum current and maximum torque) , The initial value is out of the range of the minimum stator current curve and the maximum stator current curve.

The graph of FIG. 6 shows the MTPA curve 602, the minimum stator current curve 604, the maximum stator current curve 606, and the initial stator current curve 608, respectively. 6, when the target torque error value is set to 0.1 and the initial stator current value is set to be a curve 602, and the calculation of Equation (10) is performed once, the minimum stator current value and the maximum stator current value are set to The minimum stator curve 604 and the maximum stator current curve 606 can be obtained. The control unit 506 must set the initial stator current value within the setting range defined by the minimum stator curve 604 and the maximum stator current curve 606. [ In the embodiment of FIG. 6, it can be seen that the arbitrarily set initial stator current curve 608 deviates from the setting range by the minimum stator curve 604 and the maximum stator current curve 606.

7 is a graph showing the relationship between the initial stator current value and the initial stator current value when the target torque error value is set to 0.1 and the initial stator current value is set as a linear function connecting the origin (maximum current and maximum torque) , The initial value is within the range of the minimum stator current curve and the maximum stator current curve.

The graph of FIG. 7 shows an MTPA curve 702, a minimum stator current curve 704, a maximum stator current curve 706, and an initial stator current curve 708, respectively. 7, when the target torque error value is set to 0.1 and the initial stator current value is set to be a curve 702 and the calculation of Equation (10) is performed twice, the minimum stator curve 704 and the maximum stator current The setting range by the curve 706 is much larger than in Fig. Also, the initial stator current curve 708, which is a linear function set as shown in FIG. 7, is included within the setting range by the minimum stator curve 704 and the maximum stator current curve 706. Accordingly, the controller 506 may set the initial stator current value to be a linear function so as to be included in the calculated range as shown in FIG. The controller 506 may set the initial stator current value to at least two linear functions so as to be included in the calculated range as shown in FIG.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, But the present invention is not limited thereto.

Claims (5)

An input unit for receiving a target torque; And
Calculating a minimum stator current value for generating the target torque based on the initial stator current value and a preset target torque error value, setting an initial stator current value to be included in a predetermined set range, And a controller for calculating a D-axis current command and a Q-axis current command for generating the target torque
The motor control device comprising:
The method according to claim 1,
The control unit
Calculating a minimum stator current value based on a preset target torque error value and a predetermined number of repeated times to calculate a setting range of an initial stator current value and setting the initial stator current value to be included in the setting range
Motor control device.
3. The method of claim 2,
The initial stator current value
At least one linear function included in the setting range
Motor control device.
3. The method of claim 2,
The control unit
The minimum stator current value is calculated by repeatedly calculating the following formula (1)
Motor control device.

[Equation 1]
Figure 112016074108214-pat00012

(I s, n is the minimum stator current value,
Figure 112016074108214-pat00013
Target torque error value)
The method according to claim 1,
The control unit
The D-axis current command and the Q-axis current command are calculated using the following equation (2)
Motor control device.

&Quot; (2) "
Figure 112015050185111-pat00014

(Where I d is the D axis current command, I q is the Q axis current command, I s is the minimum stator current value, L d is the D axis inductance, L q is the Q axis inductance, and λ f is the flux density)
KR1020150072953A 2015-05-26 2015-05-26 Apparatus for controlling motor KR101693424B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020150072953A KR101693424B1 (en) 2015-05-26 2015-05-26 Apparatus for controlling motor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150072953A KR101693424B1 (en) 2015-05-26 2015-05-26 Apparatus for controlling motor

Publications (2)

Publication Number Publication Date
KR20160139104A KR20160139104A (en) 2016-12-07
KR101693424B1 true KR101693424B1 (en) 2017-01-06

Family

ID=57573740

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150072953A KR101693424B1 (en) 2015-05-26 2015-05-26 Apparatus for controlling motor

Country Status (1)

Country Link
KR (1) KR101693424B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210117749A (en) 2020-03-20 2021-09-29 강원대학교산학협력단 Mtpa control method of permanent magnet synchronous motor using optimization technique

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107959452B (en) * 2017-12-05 2019-08-20 湖南大学 A kind of operating current of permanent magnet synchronous motor determines method and device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100680778B1 (en) * 2004-11-09 2007-02-08 현대자동차주식회사 Current map drawing out method of interior permanent magnet synchronous motor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210117749A (en) 2020-03-20 2021-09-29 강원대학교산학협력단 Mtpa control method of permanent magnet synchronous motor using optimization technique

Also Published As

Publication number Publication date
KR20160139104A (en) 2016-12-07

Similar Documents

Publication Publication Date Title
KR101693427B1 (en) Method for controlling motor
KR100761928B1 (en) Self tuning method and apparatus for permanent magnet sensorless control
US8310186B2 (en) Apparatus for carrying out improved control of rotary machine
KR101643488B1 (en) Control system
JP5536845B2 (en) Induction motor rotor time constant estimation device
KR20150000363A (en) Method and Apparatus for controlling torque of Permanent Magnet Synchronous Motor
CN108092597B (en) Method and system for controlling wound rotor synchronous motor
US9729097B2 (en) Apparatus for controlling induction machine
KR101353583B1 (en) Speed controller using parameter estimation of interior permanent magnet synchronous motor and its method
US20210078145A1 (en) Power tool
US10707793B2 (en) Method and apparatus for operating a synchronous machine having a permanent-magnet rotor
KR101693424B1 (en) Apparatus for controlling motor
Hu et al. Characterizing the torque lookup table of an IPM machine for automotive application
JP4056237B2 (en) Control device for synchronous machine
JPWO2015083449A1 (en) Motor control device and control method
US20150194921A1 (en) Motor control device capable of switching between application and non-application of magnetic flux control
US10333446B2 (en) Controller for induction motor
KR20130084843A (en) Method and apparatus for controlling a ipmsm based on the full order observer
US20140306629A1 (en) Motor drive control system
JP6937211B2 (en) Variable magnetic field motor control method and control device
EP3683958A1 (en) Control device and control method for synchronous electric motor
JP2018085852A (en) Current control method for variable magnetic flux type rotary electric machine, and current control device
KR101756146B1 (en) Method of dq Currents calculating and torque control for interior permanent magnet synchronous motor of electric vehicle
KR102300785B1 (en) Control apparatus and method for mdps drive motor
US11894723B2 (en) Electric tool

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
FPAY Annual fee payment

Payment date: 20191219

Year of fee payment: 4