KR101878090B1 - Method and system for controlling motor - Google Patents

Abstract

A motor control system and method for controlling a motor by compensating for a harmonic component of a motor when there is a restriction on a sampling frequency for sampling factors for controlling the motor is disclosed. The motor control system comprising: a harmonic table for receiving a torque command of the motor and outputting a pre-stored variable value corresponding to the input torque command; A harmonic compensation compensation calculator for calculating a voltage command compensation value by applying a variable value output from the harmonic table, a rotation angle and an angular velocity detected by the motor to a predetermined harmonic compensation formula; And a current controller for generating a voltage command value of the motor for following a current command value with a value obtained by detecting a current provided to the motor at a predetermined sampling period, wherein the voltage command value is a value obtained by adding the voltage command compensation value To control the motor.

Description

METHOD AND SYSTEM FOR CONTROLLING MOTOR

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control system and method, and more particularly, to a motor control system and method for controlling a motor by compensating harmonic components of a motor when there is a restriction on a sampling frequency for sampling factors for controlling the motor .

Background Art [0002] Eco-friendly vehicles such as electric vehicles, hybrid vehicles, plug-in hybrid vehicles, and fuel cell vehicles are vehicles that generate driving force by driving electric motors using electric energy. In order to drive a motor used in an environmentally friendly vehicle, an inverter is required to convert the DC power to apply a multiphase AC power to the motor.

Typically, the inverter includes switching elements for generating polyphase power, which operate in accordance with the switching frequency fsw. Meanwhile, in order to adjust the output power of the inverter for motor control, various factors related to the motor are detected according to the sampling frequency and an operation for control is performed. Here, the switching frequency fsw is generally designed to be a value which is the same as or about twice as large as the sampling frequency fsamp and which is much larger than the rotation frequency fr of the motor.

(For example, a motor control unit (MCU)) that performs an arithmetic operation for increasing or controlling the inverter switching loss and noise, as the sampling frequency fsw is larger in the torque control (current control) It is limited to a certain band or less due to various limitations such as the calculation time constraint of the internal processor.

In the case of the fundamental wave control of the motor, the control for compensating the harmonics of the motor is different, though it is not a serious problem because the sampling can be sufficiently secured per control cycle (motor rotation period, Tr = 1 / fr). For example, if 6 harmonic compensation control is to be performed, the sampling rate per a control period (Tr / 6) becomes insufficient and the control through the controller becomes impossible.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

KR 10-2006-0092607 A

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a motor control system and method for controlling a motor by compensating harmonic components of a motor when there is a restriction on a sampling frequency for sampling factors for controlling the motor.

According to an aspect of the present invention,

A harmonic table for receiving a torque command of the motor and outputting a pre-stored variable value corresponding to the input torque command;

A harmonic compensation compensation calculator for calculating a voltage command compensation value by applying a variable value output from the harmonic table, a rotation angle and an angular velocity detected by the motor to a predetermined harmonic compensation formula;

And a current controller for generating a voltage command value for the motor to follow the current command value when the value of the current detected by the motor is detected at a predetermined sampling period,

And the motor control unit controls the motor by a value obtained by adding the voltage command compensation value to the voltage command value.

일 수 있다. 상기 고조파 보상 수식에서, A 및 B는 상기 고조파 테이블에서 출력되는 변수값이며,

은 전압 지령 보상값의 D축 성분이고,

은 전압 지령 보상값의 Q성분이며, θr은 상기 모터의 회전각이고, ωr는 상기 모터의 각속도이며, Tsamp는 샘플링 주기를 나타내고, n은 보상하고자 하는 고조파의 차수를 나타내며, m은 전압 지령 보상값의 보상 시점을 나타내는 값이다.In an embodiment of the present invention,

Lt; / RTI > In the harmonic compensation formula, A and B are variable values output from the harmonic table,

Axis component of the voltage command compensation value,

Where r is the rotational angle of the motor, r is the angular speed of the motor, Tsamp is the sampling period, n is the order of the harmonic to be compensated, m is the voltage command compensation It is a value indicating the compensation point of the value.

One embodiment of the present invention may further include a harmonic controller that generates a voltage command additional compensation value for controlling the harmonic component to be zero, the harmonic component being provided to the motor. In this case, an embodiment of the present invention controls the motor by adding the voltage command compensation value and the voltage compensation additional compensation value to the voltage command value.

According to another aspect of the present invention,

Inputting a torque command to a harmonic table in which a variable value corresponding to a torque command of the motor is prestored, and deriving the variable value;

Deriving a voltage command compensation value by applying the variable value and a rotation angle and an angular velocity detected by the motor to a predetermined harmonic compensation formula;

Generating a voltage command value for the motor to follow the current command value when the value of the current provided to the motor is detected at a predetermined sampling period; And

Controlling the motor by adding the voltage command compensation value to the voltage command value;

And a motor control method.

일 수 있다. 상기 고조파 보상 수식에서, A 및 B는 상기 고조파 테이블에서 출력되는 변수값이며,

은 전압 지령 보상값의 D축 성분이고,

은 전압 지령 보상값의 Q성분이며, θr은 상기 모터의 회전각이고, ωr는 상기 모터의 각속도이며, Tsamp는 샘플링 주기를 나타내고, n은 보상하고자 하는 고조파의 차수를 나타내며, m은 전압 지령 보상값의 보상 시점을 나타내는 값이다.In an embodiment of the present invention,

Lt; / RTI > In the harmonic compensation formula, A and B are variable values output from the harmonic table,

Axis component of the voltage command compensation value,

Where r is the rotational angle of the motor, r is the angular speed of the motor, Tsamp is the sampling period, n is the order of the harmonic to be compensated, m is the voltage command compensation It is a value indicating the compensation point of the value.

One embodiment of the present invention may further include generating a voltage command additional compensation value for controlling the harmonic component of the current provided to the motor to be zero. In this case, in an embodiment of the present invention, the step of controlling the motor may control the motor by adding the voltage command compensation value and the voltage command compensation compensation value to the voltage command value.

According to the motor control system and method, a sufficient sample can be secured, accurate harmonic compensation can be performed, and the torque ripple and operability of the motor can be improved accordingly.

Further, according to the motor control system and method, it is possible to manufacture a simpler data table, thereby shortening the number of manufacturing steps and manufacturing time.

Further, according to the motor control system and method, there is no hardware design change, and performance improvement is possible without additional cost increase.

1 is a block diagram schematically showing a motor inverter system to which a motor control system and method according to an embodiment of the present invention is applied.
2 is a configuration diagram showing a motor control system and method according to an embodiment of the present invention.
3 is a block diagram showing a motor control system and method according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The motor control system and method according to various embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

1 is a block diagram schematically showing a motor inverter system to which a motor control system and method according to an embodiment of the present invention is applied.

1, a motor inverter system to which a motor control system and method according to an embodiment of the present invention is applied includes a battery 10 which is a DC power source, and a battery 10 connected between the input terminal of the battery 10 and the inverter 30 A capacitor 20 and an inverter 30 that converts the DC power provided from the battery 10 to AC power and supplies the AC power to the motor 40 and a motor 40 driven by AC power provided from the inverter 30, (Iu, Iv) among the polyphase currents provided to the motor 40 and a motor (not shown) detected by the rotation angle detector 50. The rotation angle detector 50 detects the rotation angle of the motor 40, And a controller (100) for controlling the switching elements of the inverter (30) based on the rotation angle

In FIG. 1, reference numeral 41 denotes a fundamental wave for driving the motor, that is, a counter electromotive force component due to the rotation frequency fr of the motor, and 42 denotes a harmonic of the motor (for example, Of the back electromotive force component.

The motor control system and method according to an embodiment of the present invention generates a harmonic compensation voltage for compensating the harmonic component of the motor by the calculation of the controller 100 and applies it to the inverter 30 (S1-S6) in the switching elements S1-S6.

Fig. 2 is a configuration diagram showing a motor control system and method according to an embodiment of the present invention, and Fig. 3 is a configuration diagram showing a motor control system and method according to another embodiment of the present invention. The configuration shown in Figs. 2 and 3 may be implemented by the controller 100 in the motor inverter system of Fig. The controller 100 may include a processor that performs various calculations for motor control, a memory that stores data tables and the like that are used for motor control, and a circuit that performs an electrical operation that is necessary for motor control.

Referring to FIG. 2, a motor control system according to an embodiment of the present invention includes a harmonic table 150 for deriving a torque command dependent variable applied to an equation for harmonic compensation, The voltage command compensation value for compensating the voltage command for controlling the motor 40 is calculated by calculating a harmonic compensation equation consisting of the derived torque command dependent variable and the motor rotation angle? R and the angular speed? R of the motor 40 And a harmonic compensation compensation operation unit 160 for generating a harmonic compensation function.

The harmonic table 15 stores a torque command dependent variable determined in advance by an experimental method. The harmonic table 15 receives the torque command Te and outputs the pre-stored variable values A and B corresponding to the input torque command.

The voltage command compensation value computed by the harmonic compensation computation unit 160 may be reflected in the voltage command value generated by the current controller 130 of the motor so that the voltage command compensated for the influence of the harmonic component may be provided to the inverter.

Here, the current controller 10 detects at least a part of the current command value I ^* dqsr corresponding to the torque command for the motor 40 and the polyphase current input to the inverter, and outputs the inverter output current Iuvw. samp) and outputs a proportional-integral, such as the inverter output current (Iuvw.samp) a current command value to control the manner of (I ^* dqsr) a voltage command value (V ^* dqsr for controlling so as to follow a).

The voltage command value V ^* dqsr is converted by the coordinate converter 140 into the three-phase voltage value of the UVW in the form of the DQ voltage value and the switching elements S1 to S6 in the inverter 30 for outputting the three- And supplies the determined duty to the switching elements S1 to S6 so that the output control of the inverter 30 can be performed.

2, reference numeral 110 designates a sample-and-hold circuit for sampling and holding the inverter output current Iuvw at a predetermined sampling cycle, and reference numeral 120 designates the sampled input current as a rotation angle of the motor Based on the DQ current.

)을 생성하는 것을 특징으로 한다.Various embodiments of the present invention use the harmonic table 150 to derive the torque command dependent variables A and B corresponding to the torque command Te and calculate the torque command dependent variables A and B and the sampling frequency fsamp (V ^* dqsr) based on the rotation angle [theta] r of the motor 40 and the angular velocity [omega] r of the motor 40 input for each of the voltage command compensation values

).

The harmonic compensation control technique according to various embodiments of the present invention is based on the harmonic compensation formula as shown in Equation 1 below.

[Formula 1]

은 전압 지령 보상값의 D축 성분이고,

은 전압 지령 보상값의 Q성분이며, Tsamp는 샘플링 주기를 나타내고, n은 보상하고자 하는 고조파의 차수를 나타내며, m은 전압 지령 보상값의 보상 시점을 나타내는 값이다.In Equation (1)

Axis component of the voltage command compensation value,

Is the Q component of the voltage command compensation value, Tsamp is the sampling period, n is the order of the harmonic to be compensated, and m is the compensation time point of the voltage command compensation value.

)을 생성하기 위해 적용되는 수식이며, 고조파 테이블(150)은 토크 지령(Te)를 기반으로 식 1의 변수(A, B)를 도출하는데 적용된다.In Equation (1), the harmonic compensation formula calculator 160 calculates a voltage command compensation value

, And the harmonic table 150 is applied to derive the variables A and B of Equation 1 based on the torque command Te.

Equation 1 can be derived by the following procedure using the DQ voltage equation of a known motor.

The DQ voltage expression of the known motor is expressed by the following Equation 2.

[Formula 2]

Vdqsr represents the motor voltage, Vdsr represents the D axis component of the motor voltage, and Vqsr represents the Q axis component of the motor voltage. Idsr represents the D axis component of the motor current, and Iqsr represents the Q axis component of the motor current. Rd denotes a D-axis resistance component, Rq denotes a Q-axis resistance component, Ld denotes a D-axis inductance component, and Lq denotes a Q-axis inductance component. And? Pm represents the magnetic flux of the rotor magnet.

, 모터 전압의 Q축 고조파 성분은

, 모터 전류의 D축 고조파 성분은

, 모터 전류의 Q축 전류의 고조파 성분은

)을 포함한다고 하면, 모터 전압과 모터 전류는 각각 다음의 식 3과 식 4로 표현될 수 있다. 또한, λpm은 고조파 성분을 고려하여 다음의 식 5와 같이 표현될 수 있다.In the above equation (2), the motor voltage (Vdqsr) and the motor current (Idqsr) are the n-th order harmonic component

, The Q-axis harmonic component of the motor voltage is

, The D-axis harmonic component of the motor current is

, The harmonic component of the Q-axis current of the motor current

), The motor voltage and the motor current can be expressed by the following equations (3) and (4), respectively. Further,? Pm can be expressed by the following Equation 5 in consideration of harmonic components.

[Formula 3]

[Formula 4]

[Formula 5]

는 회전자 자석의 자속을 타내고,

는 회전자 자석 자속의 n차 고조파 성분을 나타낸다.In the above Equations 3 to 5, n represents the order of the harmonics, and Idsr_nh and Iqsr_nh represent the peak values of the D-axis component and the Q-axis component of the n-th order harmonic current, respectively. Also,

The magnetic flux of the rotor magnet is emitted,

Represents the nth order harmonic component of the rotor magnet flux.

After substituting the equations 4 and 5 into the equation 3, the motor voltage can be expressed by the following equation 6, considering that the resistance component is a relatively small value.

[Formula 6]

In Equation 6, only the harmonic components are summarized as Equation 7 below.

[Equation 7]

The above Equation 7 can be summarized as Equation 8 below. If, when the harmonic compensation is performed well with no current ripple I _{dsr _nh} and I _{qsr _nh} is 0 (zero) it is in this case expression when compared to the 8 and Equation 1 variables A and B is obtained using the equation 9 and equation 10 and Can appear together.

[Equation 8]

[Equation 9]

[Equation 10]

Here, in the various embodiments of the present invention, '? R + mTsamp? R' is applied instead of '? R' in Equations 3 to 10 in order to consider the compensation time point at which the voltage command compensation value for compensating the harmonics is applied. This is because the voltage command compensation value calculated through the voltage command compensation at the one sampling time can be applied at least after the next sampling time. For example, in order to apply the voltage command compensation value to the intermediate point between the sampling time immediately after the voltage command compensation value is computed at one sampling time and the sampling time immediately after the next sampling time, m = 1.5.

On the other hand, the harmonic table 150 for calculating the torque command dependent variables A, B can be derived through an experimental method. A method for deriving the harmonic table 150 will be briefly described as follows.

First, after the motor inverter system as shown in Fig. 1 is prepared, the controller 100 is initialized.

Then, the motor is driven at a low speed under the condition (fsamp >> n * fr) that the value obtained by multiplying the order (n) of harmonics to compensate the rotational frequency fr of the motor 40 is significantly smaller than the sampling frequency fsamp. The low-speed drive state of these motors is a harmonic correction mode, which can accurately extract harmonic components on the basis of sufficient sampling, and enables table fabrication and accurate voltage compensation.

Next, when the output value of the controller 100 corresponding to each torque command is checked and matched with the equation 1 while sequentially increasing the torque command Te as used in the actual motor drive control, the harmonic wave for generating the voltage command compensation value The table 150 can be created.

This method of generating the harmonic table 150 can calculate the accurate voltage command compensation value for harmonic compensation because the harmonic is measured in a state in which sampling is sufficiently secured. Since the table is created using the controller output value, It is possible to omit it, thereby saving manpower and preparation time.

)을 추가적으로 합성하기 위한 고조파 제어기(170)을 더 포함한다.Next, referring to FIG. 3, an embodiment of the present invention as shown in FIG. 3, as compared with the embodiment described in FIG. 2, calculates a voltage command compensation value

And a harmonic controller 170 for further synthesizing the harmonics.

)을 제공받으며, 고조파 성분(

)이 0(zero)가 되도록 제어할 수 있는 전압 지령 보상값(

)을 생성한다.The harmonic controller 170 _converts the harmonic component (I _dqsr ) of the motor current extracted through the high-pass filter or the like from the motor current I _dqsr input to the current controller 130

), And the harmonic component (

) Can be controlled to be zero (zero)

).

3 may perform an appropriate harmonic compensation control through the harmonic controller 170 when an incorrect value is output in a changed environment of the harmonic table 150 that has been set in advance by a change in use environment of the motor inverter system There is an advantage. In addition, as in the embodiment shown in FIG. 2, the transient response of the controller, which occurs when the harmonic table 160 and the harmonic compensation formula applying unit 170 are used to compensate for the deflection, can be improved.

While the invention has been shown and described with respect to the specific embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit of the invention, And will be apparent to those skilled in the art.

10: Battery 20: Capacitor
30: inverter 40: motor
50: rotation angle detector 100: controller
110: sample and hold unit 120: coordinate transformation unit
130: current controller 140:
150: Harmonic table 160: Harmonic compensation formula application part

Claims (6)

A harmonic table for receiving a torque command of the motor and outputting a pre-stored variable value corresponding to the input torque command;
A harmonic compensation compensation calculator for calculating a voltage command compensation value by applying a variable value output from the harmonic table, a rotation angle and an angular velocity detected by the motor to a predetermined harmonic compensation formula;
And a current controller for generating a voltage command value for the motor to follow the current command value when the value of the current detected by the motor is detected at a predetermined sampling period,
Controls the motor by a value obtained by adding the voltage command compensation value to the voltage command value,
The harmonic compensation formula may be expressed as:

Lt;
In the harmonic compensation formula, A and B are variable values output from the harmonic table,

Axis component of the voltage command compensation value,

Where r is the rotational angle of the motor, r is the angular speed of the motor, Tsamp is the sampling period, n is the order of the harmonic to be compensated, m is the voltage command compensation And a value indicating a time point of compensation of the value. delete The method according to claim 1,
Further comprising a harmonic controller for receiving a harmonic component of a current provided to the motor and generating a voltage command additional compensation value for controlling the harmonic component to be zero,
And the motor control unit controls the motor by a value obtained by adding the voltage command compensation value and the voltage command compensation compensation value to the voltage command value. Inputting a torque command to a harmonic table in which a variable value corresponding to a torque command of the motor is prestored, and deriving the variable value;
Deriving a voltage command compensation value by applying the variable value and a rotation angle and an angular velocity detected by the motor to a predetermined harmonic compensation formula;
Generating a voltage command value for the motor to follow the current command value when the value of the current provided to the motor is detected at a predetermined sampling period; And
And controlling the motor by adding the voltage command compensation value to the voltage command value,
The harmonic compensation formula may be expressed as:

Lt;
In the harmonic compensation formula, A and B are variable values output from the harmonic table,

Axis component of the voltage command compensation value,

Where r is the rotational angle of the motor, r is the angular speed of the motor, Tsamp is the sampling period, n is the order of the harmonic to be compensated, m is the voltage command compensation And a value indicating a time point at which the value is compensated. delete The method of claim 4,
Further comprising generating a voltage command additional compensation value for controlling the harmonic component of the current supplied to the motor to be zero,
Wherein the step of controlling the motor controls the motor by adding the voltage command compensation value and the voltage command compensation compensation value to the voltage command value.

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