KR102366757B1 - Motor control apparatus and controlling method thereof - Google Patents

Abstract

The present invention relates to a motor control device and a control method thereof. A motor control apparatus and a control method according to the present invention estimate a phase error between two motors through a difference in current flowing through the two motors, compare the phase error with a threshold value to adjust an attenuation coefficient, and set a compensation current By doing so, two motors can be controlled through one motor control device. The motor control apparatus and the control method according to the present invention have the effect of preventing the synchronization between the two motors from being released by using the same method as above.

Description

Motor control device and its control method

The present invention relates to a motor control device and a control method thereof.

The motor control device is a device for driving a motor including a rotor performing rotational motion and a stator around which coils are wound.

Such a motor control device receives the AC voltage from the power supply and supplies it to the three-phase motor. At this time, the AC voltage supplied from the power supply is changed to an appropriate voltage to operate the three-phase motor through a converter, smoothing capacitor, inverter, etc. of the motor control device and applied to the three-phase motor. In this case, the inverter of the motor control device includes a plurality of switching elements, and the switching operation of the switching elements is controlled by the controller. In addition, the voltage applied to the three-phase motor is determined according to the switching operation of the switching element, and accordingly, the operating speed of the three-phase motor is determined.

Such a motor control device may be designed to be controlled by connecting two motors to one motor control device. Such a motor control device is disclosed in Patent Registration KR 10-1623652.

Methods of controlling two motors through one motor control device include an average current control method, a master-slave control method, and the like.

Among them, the master-slave control method according to the prior art is a method of controlling using one of two motors as a master motor. At this time, the motor control device synchronizes the phases of the master motor and the slave motor so that the current is stable, so that the two motors can be operated continuously. However, when an external force is applied to the master motor or the slave motor, the phase synchronization between the master motor and the slave motor may be released.

Conventionally, in order to solve this problem, the phases of the two motors are synchronized by compensating for the pulsation of the current. However, this method does not consider the periodic characteristics of the phase error between the master motor and the slave motor, so the effect is small when the phase error is 45 degrees or less.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device for controlling two motors using one motor control device, and a method for controlling the same.

Another object of the present invention is to provide a motor control device and a control method for controlling two motors using one motor control device by estimating a phase error between the two motors.

Another object of the present invention is to provide a motor control apparatus and a method for controlling the same for controlling two motors using one motor control apparatus by setting a threshold value of a phase error between the two motors.

Another object of the present invention is to provide a motor control device and a control method thereof for controlling two motors using one motor control device by setting a limit value.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned may be understood by the following description, and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the appended claims.

A motor control apparatus and a control method according to the present invention detect currents flowing through two motors, and through this, control a voltage applied to a switching element of an inverter, thereby controlling two motors through one motor control apparatus there is.

In addition, the motor control apparatus and the control method according to the present invention estimate a phase error between two motors through a difference in current flowing through the two motors, and set a compensation current using the phase error, thereby providing a single motor control apparatus can control two motors.

In addition, the motor control apparatus and the control method according to the present invention set a threshold value of the phase error between two motors, compare the phase error and the threshold value, and adjust the damping coefficient, using one motor control apparatus Two motors can be controlled.

In addition, the motor control device and the control method according to the present invention can control two motors using one motor control device by setting a limit value and setting the limit value as the compensation current when the compensation current is greater than the limit value.

The motor control device and the control method according to the present invention control two motors through one motor control device, thereby reducing costs by not installing as many motor control devices as the number of motors when driving a plurality of motors there is

In addition, the motor control apparatus and the control method according to the present invention prevent the synchronization between the two motors from being released by estimating the phase error between the two motors and setting the compensation current through the difference in current flowing through the two motors There is an effect that can be done.

In addition, the motor control device and the control method according to the present invention set a threshold value of the phase error between the two motors and adjust the damping coefficient, thereby more effectively preventing the two motors from being out of synchronization when the phase error is large. can have an effect.

In addition, the motor control device and the control method according to the present invention set a limit value, and when the compensation current is greater than the limit value, set the limit value as the compensation current, thereby preventing abrupt changes in voltage or current supplied to two motors. It works.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 is an internal block diagram of a motor control apparatus according to an embodiment of the present invention.
2 is an internal circuit diagram of a motor control apparatus according to an embodiment of the present invention.
3 is a view showing a detailed structure of a control unit of a motor control apparatus according to an embodiment of the present invention.
4 is a diagram illustrating a detailed structure of a compensation current setting unit of a motor control apparatus according to an embodiment of the present invention.
5 is a diagram illustrating a detailed structure of a switching voltage adjusting unit of a motor control apparatus according to an embodiment of the present invention.
6 is a flowchart illustrating a method in which a controller of a motor control apparatus adjusts a voltage applied to a switching element of an inverter.
7 is a graph for explaining a method of setting a threshold value of a motor control apparatus according to an embodiment of the present invention.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

In addition, when it is described that a component is “connected”, “coupled” or “connected” to another component, the components may be directly connected or connected to each other, but other components are “interposed” between each component. It should be understood that “or, each component may be “connected,” “coupled,” or “connected,” through another component.

Hereinafter, a motor control apparatus and a control method thereof according to some embodiments of the present invention will be described.

1 is an internal block diagram of a motor control apparatus according to an embodiment of the present invention.

2 is an internal circuit diagram of a motor control apparatus according to an embodiment of the present invention.

1 and 2 , the motor control apparatus 100 according to an embodiment of the present invention may include an inverter 110 and a controller 120 . In addition, the motor control apparatus 100 according to an embodiment of the present invention may further include a converter 130 and a smoothing capacitor 140 . The motor control apparatus 100 according to an embodiment of the present invention is for driving a motor in a sensorless manner.

The inverter 110 includes a plurality of switching elements S1, S2, S3, S4, S5, and S6. The inverter 110 converts a DC voltage into a three-phase AC voltage of a predetermined frequency through an operation in which the plurality of switching elements S1, S2, S3, S4, S5, and S6 are turned on/off to convert the first motor 200 and It may be supplied to the second motor 210 to drive the first motor 200 and the second motor 210 .

Inverter 110 is a pair of upper switching elements (S1, S3, S5) and lower switching elements (S2, S4, S6) connected in series with each other, respectively, a total of three pairs of upper and lower switching elements are parallel to each other can be connected to The switching elements S1 , S2 , S3 , S4 , S5 , and S6 of the inverter 110 may be power transistors, for example, insulated gate bipolar transistors.

The plurality of switching elements S1 , S2 , S3 , S4 , S5 , and S6 in the inverter 110 perform a switching operation based on the voltage applied from the controller 120 . Accordingly, a three-phase AC voltage having a predetermined frequency is output to the first motor 200 and the second motor 210 .

The controller 120 controls the inverter 110 . In more detail, the control unit 120 detects the current flowing in three phases of the first motor 200 and the second motor 210 , and uses the detected current to a plurality of switching elements S1 and S2 in the inverter 110 . , S3, S4, S5, S6) adjusts the voltage applied to it.

The control unit 120 selects any one of the first motor 200 and the second motor 210 as the master motor, and selects the other motor as the slave motor to master the first motor through the slave control method. 200 and the second motor 210 may be controlled.

In the master-slave control method, the control unit 120 compares the load applied to the first motor 200 with the load applied to the second motor 210, and then selects a motor to which a relatively larger load is applied as the master motor. and selecting a motor to which a relatively small load is applied as a slave motor to control the first motor 200 and the second motor 210 . At this time, the controller 120 detects the current flowing in three phases of the first motor 200 and the second motor 210 , and feeds back the detected current to a plurality of switching elements S1 , S2 , S3 in the inverter 110 . , S4, S5, S6) adjusts the voltage applied to it.

Hereinafter, the controller 120 controls the first motor 200 and the second motor 210 using the master-slave control method, selects the first motor 200 as the master motor, and selects the second motor 210 . It is explained assuming the situation in which is selected as the slave motor. However, the present invention may also be applied to a situation in which the controller 120 selects the second motor 210 as the master motor and the first motor 200 as the slave motor.

The control unit 120 includes a speed estimation unit 121 , a compensation current setting unit 122 , and a switching voltage control unit 123 . In this case, the switching voltage adjusting unit 123 of the controller 120 may include a current command setting unit 123a, a current command adjusting unit 123b, and a voltage adjusting unit 123c. A more detailed operation of the components included in the control unit 120 will be described later with reference to FIGS. 3 to 5 .

The converter 130 converts the input AC voltage applied through the power supply unit 300 into a DC voltage and outputs it. The converter 130 may be formed of a diode or the like without a switching element to perform a rectification operation without a separate switching operation.

When the input AC voltage applied through the power supply unit 300 is a single-phase AC voltage, the converter 130 may have a structure in which four diodes are configured in the form of a bridge. Also, when the input AC voltage is a single-phase AC voltage, the converter 130 may have a half-bridge structure in which two switching elements and four diodes are connected.

When the input AC voltage is a three-phase AC voltage, the converter 130 may have a structure in which six diodes are configured in a bridge form. Also, when the input AC voltage is a three-phase AC voltage, the converter 130 may have a structure in which six switching elements and six diodes are connected.

When the converter 130 has a structure including a switching element, the converter 130 may perform a step-up operation, a power factor improvement, and a DC voltage conversion by a switching operation of the corresponding switching element.

The smoothing capacitor 140 smoothes the DC voltage converted through the converter 130 and stores it. Although one capacitor is illustrated as the smoothing capacitor 140 in FIG. 2 , a plurality of capacitors may be provided to ensure device stability.

The first motor 200 and the second motor 210 are three-phase motors, and include a stator and a rotor, and an alternating voltage of a predetermined frequency is applied to the coils of the stators of each phase of the three phases, The rotor will rotate.

The first motor 200 and the second motor 210 are a Surface Mounted Permanent Magnet Synchronous Motor (SMPMSM), an Interior Permanent Magnet Synchronous Motor (IPMSM), and a synchronous motor. It may include a reluctance motor (Synchronous Reluctance Motor; Synrm) and the like. Among them, SMPMSM and IPMSM are Permanent Magnet Synchronous Motor (PMSM) applied with permanent magnet, and Synrm is characterized by no permanent magnet.

Hereinafter, it will be mainly described that the first motor 200 and the second motor 210 are surface-attached permanent magnet synchronous motors (SPMSM) in which permanent magnets are symmetrically formed.

3 is a view showing a detailed structure of a control unit of a motor control apparatus according to an embodiment of the present invention.

Referring to FIG. 3 , the control unit 120 of the motor control apparatus 100 according to an embodiment of the present invention includes a speed estimation unit 121 , a compensation current setting unit 122 , and a switching voltage control unit 123 . do. In this case, the switching voltage adjusting unit 123 of the controller 120 may include a current command setting unit 123a, a current command adjusting unit 123b, and a voltage adjusting unit 123c.

The control unit 120 may detect currents flowing in three phases of the first motor 200 and the second motor 210 through a detection unit (not shown) included therein. In this case, in order to detect the current, a current transformer (CT), a shunt resistor, or the like may be used in the detection unit.

The control unit 120 may detect all currents flowing in three phases of the first motor 200 and the second motor 210 through the detection unit. After detecting only the current flowing in two phases out of the three phases through the detection unit, the controller 120 may calculate the current flowing in the remaining one phase by using the three-phase balance.

The control unit 120 converts the current flowing in the three phases of the first motor 200 and the second motor 210 detected through the detection unit through the conversion unit (not shown) included therein to convert the two-phase current of the rotational coordinate system. can be converted to That is, the converter may convert the current flowing in the three phases of the first motor 200 and the second motor 210 into a magnetic flux current that is a d-axis current of the rotational coordinate system and a torque current that is a q-axis current of the rotational coordinate system.

The speed estimator 121 may estimate the speed of the first motor 200 by using a current flowing through the first motor 200 . In this case, the speed estimator 121 may use the two-phase current of the rotational coordinate system of the first motor 200 converted through the converter to estimate the speed of the first motor 200 .

The compensation current setting unit 122 uses the difference between the current flowing through the first motor 200 and the second motor 210 and the speed of the first motor 200 to the first motor 200 and the second motor 210 . ) can be estimated. In addition, the compensation current setting unit 122 may set the compensation current by using the phase error, the attenuation coefficient, and the threshold value.

A more detailed operation of the compensation current setting unit 122 may be described with reference to FIG. 4 .

4 is a diagram illustrating a detailed structure of a compensation current setting unit of a motor control apparatus according to an embodiment of the present invention.

Referring to FIG. 4 , the compensation current setting unit 122 includes the speed of the first motor 200 estimated by the speed estimation unit 121 and the first motor 200 and the second motor 210 converted through the conversion unit. The two-phase current of the rotating coordinate system of The values received by the compensation current setting unit 122 pass through the phase error estimating unit 122a. The phase error estimator 122a estimates the phase error using Equation 1. In this case, Equation 1 is as follows.

는 추정된 제1 모터(200)와 제2 모터(210) 간의 위상 오차를 나타낸다.

는 제1 모터(200)를 기준 축으로 할 때, 제1 모터(200)의 자속 전류를 의미한다.

는 제1 모터(200)를 기준 축으로 할 때, 제2 모터(210)의 자속 전류를 의미한다.

는 제1 모터(200)를 기준 축으로 할 때, 제1 모터(200)의 토크 전류를 의미한다.

는 제1 모터(200)를 기준 축으로 할 때, 제2 모터(210)의 토크 전류를 의미한다.

은 제1 모터(200)의 속도를 나타낸다. R_s는 모터(200, 210) 내의 고정자의 저항을 나타낸다. L_s는 모터(200, 210)의 상 인덕턴스를 나타낸다.

는 모터(200, 210)에 포함된 영구 자석으로부터 생기는 쇄교 자속을 나타낸다.here

denotes the phase error between the estimated first motor 200 and the second motor 210 .

denotes a magnetic flux current of the first motor 200 when the first motor 200 is used as a reference axis.

is the magnetic flux current of the second motor 210 when the first motor 200 is used as a reference axis.

is a torque current of the first motor 200 when the first motor 200 is used as a reference axis.

is a torque current of the second motor 210 when the first motor 200 is used as a reference axis.

denotes the speed of the first motor 200 . R _s represents the resistance of the stator in the motors 200 , 210 . L _s represents the phase inductance of the motors 200 and 210 .

denotes the flux linkage generated from the permanent magnets included in the motors 200 and 210 .

)는 제2 모터(210)의 자속 전류(

)와 제1 모터(200)의 자속 전류(

)의 차이(

)와 제2 모터(210)의 토크 전류(

)와 제1 모터(200)의 토크 전류(

)의 차이(

)를 통하여 추정될 수 있다. 즉, 위상 오차는 제1 모터(200) 및 제2 모터(210)에 흐르는 전류의 차이와 제1 모터(200)의 속도를 이용하여 추정될 수 있다.As can be seen from Equation 1, the phase error between the first motor 200 and the second motor 210 (

) is the magnetic flux current of the second motor 210 (

) and the magnetic flux current of the first motor 200 (

) difference (

) and the torque current of the second motor 210 (

) and the torque current of the first motor 200 (

) difference (

) can be estimated through That is, the phase error may be estimated using the difference between the currents flowing through the first motor 200 and the second motor 210 and the speed of the first motor 200 .

)를 추정할 수 있다.That is, the compensation current setting unit 122 passes the input values to the phase error estimating unit 122a included therein, so that the phase error between the first motor 200 and the second motor 210 (

) can be estimated.

)를 추정할 수 있다. 속도 오차 추정부(122b)는 입력 받은 위상 오차(

)를 PI(Proportional-Integral) 제어기를 통과시킴으로써 PI 제어한다. 그리고 속도 오차 추정부(122b)는 PI 제어기를 통해 PI 제어한 결과를 적분하고, 적분한 결과를 피드백하여 속도 오차(

)를 추정할 수 있다.Then, the compensation current setting unit 122 passes the phase error estimated through the phase error estimator 122a through the velocity error estimator 122b, so

) can be estimated. The speed error estimating unit 122b receives the inputted phase error (

) through the PI (Proportional-Integral) controller to control PI. And the speed error estimator 122b integrates the result of PI control through the PI controller, and feeds back the result of the integration to provide a speed error (

) can be estimated.

)를 적분하여 속도 오차(

)를 추정하지 않고, 위와 같이 PI 제어, 적분 및 피드백을 거쳐서 추정함으로써, 속도 오차(

)의 추정 과정에서 발생하는 노이즈를 줄일 수 있다. The speed error estimating unit 122b simply calculates the phase error (

) by integrating the speed error (

) without estimating the speed error (

), noise generated in the estimation process can be reduced.

)와 속도 오차(

)는 곱셈기를 통과하고 보상 전류 연산부(122c)로 입력된다. 보상 전류 연산부(122c)는 위상 오차(

)와 속도 오차(

)가 곱해진 결과에 감쇠 계수(K_damp)를 곱하여 보상 전류(

)를 연산할 수 있다. 이때 감쇠 계수(K_damp)는 모터를 얼마나 빠르게 동기화 시킬지 결정하는 계수로, 사용자에 의해 미리 설정될 수 있다. 즉, 보상 전류(

)는 아래의 식 2와 같이 연산될 수 있다.Then the phase error (

) and the speed error (

) passes through the multiplier and is input to the compensation current calculating unit 122c. Compensation current calculating unit 122c is a phase error (

) and the speed error (

) is multiplied by the damping factor (K _damp ) and the compensation current (

) can be calculated. At this time, the damping coefficient (K _damp ) is a coefficient that determines how quickly the motor is synchronized, and can be preset by the user. That is, the compensation current (

) can be calculated as in Equation 2 below.

)의 크기에 따라 변할 수 있다. 위상 오차(

)가 임계값 이하이면, 스위치(122e)는 오프되어 감쇠 계수(K_damp)으로 처음 설정된 값이 이용된다.At this time, the damping coefficient (K _damp ) is the estimated phase error (

) may vary depending on the size of phase error (

) is below the threshold value, the switch 122e is turned off and the value initially set as the damping coefficient (K _damp ) is used.

)가 임계값 이하이면, 제1 모터(200)와 제2 모터(210)간의 위상 오차(

)가 존재하나, 제1 모터(200)와 제2 모터(210)간의 동기화가 해제될 확률이 낮은 단계인 것이기 때문이다. 따라서 보상 전류 설정부(122)가 위상 오차(

)가 임계값 이하라고 판단하면, 감쇠 계수(K_damp)를 증가시키지 않고, 감쇠 계수(K_damp)로 처음 설정된 값을 이용한다.This is the phase error (

) is less than or equal to the threshold, the phase error between the first motor 200 and the second motor 210 (

) exists, but the probability that synchronization between the first motor 200 and the second motor 210 will be released is low. Therefore, the compensation current setting unit 122 sets the phase error (

) is below the threshold, the damping coefficient (K _damp ) is not increased, and the value initially set as the damping coefficient (K _damp ) is used.

)가 임계값보다 크면, 스위치(122e)는 온 되고, 위상 오차(

)의 음의 값이 PI 제어기(122d)를 통과하여 보상 전류 연산부(122c)에 입력된다. 이에 따라, 감쇠 계수(K_damp)는 처음 설정된 값보다 증가되고, 보상 전류 연산부(122c)는 증가된 감쇠 계수(K_damp)를 이용하여 보상 전류(

)를 연산한다.However, the phase error (

) is greater than the threshold, the switch 122e is on, and the phase error (

) passes through the PI controller 122d and is input to the compensation current calculating unit 122c. Accordingly, the damping coefficient (K _damp ) is increased than the initially set value, and the compensation current calculating unit 122c uses the increased damping coefficient (K _damp ) to generate the compensation current (

) is calculated.

)가 임계값 보다 크면, 제1 모터(200)와 제2 모터(210)간의 위상 오차(

)가 존재하고, 이로 인하여 제1 모터(200)와 제2 모터(210)간의 동기화가 해제될 확률이 높은 단계인 것이기 때문이다. 따라서 보상 전류 설정부(122)가 위상 오차(

)가 임계값 보다 크다고 판단하면 감쇠 계수(K_damp)를 증가시키고, 증가된 감쇠 계수(K_damp)를 이용한다.This is the phase error (

) is greater than the threshold, the phase error between the first motor 200 and the second motor 210 (

) exists, and due to this, the synchronization between the first motor 200 and the second motor 210 is at a high probability. Therefore, the compensation current setting unit 122 sets the phase error (

) increases the damping coefficient (K _damp ) and uses the increased damping coefficient (K _damp ) when it is determined that it is greater than the threshold value.

)의 크기에 따라 다른 크기의 감쇠 계수를 이용함으로써, 위상 오차가 클 때 보상 전류를 더 크게 하여, 제1 모터(200)와 제2 모터(210)의 동기화가 해제되는 것을 더욱 효과적으로 방지할 수 있다.As such, the phase error (

), by using a damping coefficient of a different magnitude according to the magnitude of the phase error, when the phase error is large, the compensation current is made larger, and the synchronization of the first motor 200 and the second motor 210 can be more effectively prevented from being released. there is.

)와 비교하는 대상인 임계값은 제2 모터(210)에 걸리는 토크의 변화량이 0이 되도록 하는 제1 모터(200) 및 제2 모터(210) 간의 위상 오차와 일정한 마진을 두고 설정된다. 보상 전류 설정부(122)가 임계값을 설정하는 보다 상세한 방법은 도 7을 이용하여 후술하도록 한다.In this case, the phase error (

) and the threshold value to be compared are set with a constant margin and a phase error between the first motor 200 and the second motor 210 so that the amount of change in torque applied to the second motor 210 becomes 0. A more detailed method for the compensation current setting unit 122 to set the threshold will be described later with reference to FIG. 7 .

)는 제한부(122f)를 통과한다. 제한부(122f)는 보상 전류(

)를 미리 설정된 제한값과 비교하여, 보상 전류(

)가 제한값보다 크면 제한값을 보상 전류(

)로 설정한다.Then the calculated compensation current (

) passes through the limiting portion 122f. The limiter 122f is a compensation current (

) with the preset limit value, the compensation current (

) is greater than the limit value, the limit value is set to the compensation current (

) is set.

)가 과도해지는 것을 방지한다. 이를 통해, 하기 설명될 전류 지령 조절부(123b)를 통해 출력되는 전류 지령이 급격히 변하는 것을 방지하여, 최종적으로 제1 모터(200) 및 제2 모터(210)에 공급되는 전압 또는 전류가 급격하게 변하는 것을 방지한다. 이로 인해, 제1 모터(200) 및 제2 모터(210)를 더욱 안정적으로 제어할 수 있다.Compensation current setting unit 122 through the limiting unit (122f) compensation current (

) to prevent excessive Through this, the current command output through the current command control unit 123b, which will be described below, is prevented from changing rapidly, and the voltage or current supplied to the first motor 200 and the second motor 210 is rapidly increased. prevent change Accordingly, the first motor 200 and the second motor 210 can be more stably controlled.

)를 이용하여, 인버터(110)의 스위칭 소자(S1, S2, S3, S4, S5, S6)에 인가되는 전압을 조절한다.Returning to FIG. 3 again, the switching voltage adjusting unit 123 determines the target speed, the estimated speed of the first motor 200 and the compensation current (

) to adjust the voltage applied to the switching elements S1 , S2 , S3 , S4 , S5 , and S6 of the inverter 110 .

A more detailed operation of the switching voltage adjusting unit 123 may be described with reference to FIG. 5 .

5 is a diagram illustrating a detailed structure of a switching voltage adjusting unit of a motor control apparatus according to an embodiment of the present invention.

Referring to FIG. 5 , the switching voltage adjusting unit 123 includes a current command setting unit 123a, a current command adjusting unit 123b and a voltage adjusting unit 123c.

The current command setting unit 123a may set the current command using a target speed preset by the user and the estimated speed of the first motor 200 . The current command setting unit 123a may calculate a difference value between the target speed and the speed of the first motor 200 and set the current command by passing the calculated difference value through the PI controller.

)와 전류 지령 설정부(123a)를 통해 설정된 전류 지령을 이용하여 전류 지령을 조절할 수 있다. 전류 지령 조절부(123b)는 전류 지령 설정부(123a)가 설정한 전류 지령에 보상 전류 설정부(122)를 통해 설정된 보상 전류(

)를 더함으로써 전류 지령을 조절할 수 있다.The current command control unit 123b sets the compensation current (

) and the current command set through the current command setting unit 123a may be used to adjust the current command. The current command control unit 123b sets the compensation current (

) can be added to adjust the current reference.

The voltage control unit 123c controls the voltage applied to the switching elements S1, S2, S3, S4, S5, and S6 of the inverter 110 by using the current command adjusted through the current command control unit 123b. . The voltage adjusting unit 123c may adjust the voltage applied to the switching elements S1 , S2 , S3 , S4 , S5 , and S6 of the inverter 110 by passing the received current command through the PI controller.

6 is a flowchart illustrating a method in which a controller of a motor control apparatus adjusts a voltage applied to a switching element of an inverter.

Referring to FIG. 6 , the speed estimation unit 121 estimates the speed of the first motor 200 by using the current detected from the first motor 200 through the detection unit ( S600 ).

Then, the compensation current setting unit 122 uses the speed of the first motor 200 and the difference between the currents detected from the first motor 200 and the second motor 210 through the detection unit to the first motor 200 . and a phase error between the second motors 210 is estimated ( S610 ). When estimating the phase error, Equation 1 above may be used.

Thereafter, the compensation current setting unit 122 determines whether the estimated phase error is equal to or less than a threshold value (S620).

If the phase error is less than or equal to the threshold value, there is a phase error between the first motor 200 and the second motor 210 , but the probability that synchronization between the first motor 200 and the second motor 210 will be canceled is low it is a step Therefore, if the compensation current setting unit 122 determines that the phase error is less than or equal to the threshold value, the step of increasing the attenuation coefficient ( S630 ) is omitted and the process proceeds to the next step ( S640 ).

If the phase error is greater than the threshold value, there is a phase error between the first motor 200 and the second motor 210 , and due to this, the probability that the synchronization between the first motor 200 and the second motor 210 is canceled This is a high level. Therefore, when the compensation current setting unit 122 determines that the phase error is greater than the threshold value, the attenuation coefficient is increased (S630).

As described above, by using attenuation coefficients of different magnitudes according to the magnitude of the phase error, the compensation current is made larger when the phase error is large, so that the synchronization of the first motor 200 and the second motor 210 is released more effectively. can be prevented

At this time, the threshold value to be compared with the phase error is set with a constant margin from the phase error between the first motor 200 and the second motor 210 so that the amount of change in the torque applied to the second motor 210 becomes 0. A more detailed method of setting the threshold will be described later with reference to FIG. 7 .

Then, the compensation current setting unit 122 estimates the speed error between the first motor 200 and the second motor 210 using the phase error ( S640 ). In this case, the speed error can be estimated by PI control by passing the phase error through the PI controller, integrating the PI control result through the PI controller, and feeding back the integration result.

The compensation current setting unit 122 does not estimate the speed error by simply integrating the phase error, but estimates through PI control, integration, and feedback as described above, thereby reducing noise generated in the process of estimating the speed error.

And the compensation current setting unit 122 sets the compensation current by multiplying the phase error, the speed error, and the attenuation coefficient (S650). When setting the compensation current, Equation 2 above can be used.

In addition, the compensation current setting unit 122 may set the limit value as the compensation current when the set compensation current is greater than the limit value. Through this, it is possible to prevent abrupt changes in the current command due to excessive compensation current and a sudden change in voltage or current finally supplied to the first motor 200 and the second motor 210 .

Finally, the switching voltage adjusting unit 123 is applied to the switching elements S1, S2, S3, S4, S5, and S6 of the inverter 110 using the target speed, the speed of the first motor 200, and the compensation current. The voltage is adjusted (S660). The switching voltage adjusting unit 123 sets a current command using the speed and the target speed of the first motor 200 . And the current command is adjusted using the compensation current. Then, the voltage applied to the switching elements S1 , S2 , S3 , S4 , S5 , and S6 of the inverter 110 may be adjusted using the adjusted current command.

7 is a graph for explaining a method of setting a threshold value of a motor control apparatus according to an embodiment of the present invention.

)와 제2 모터(210)에 걸리는 토크(T_M2)의 관계를 나타낸 그래프를 확인할 수 있다.Referring to FIG. 7 , the phase error between the first motor 200 and the second motor 210 (

) and a graph showing the relationship between the torque T _{M2 applied} to the second motor 210 can be confirmed.

)가 크면, 제1 모터(200) 및 제2 모터(210) 간의 동기화가 해제될 수 있다. 따라서 위상 오차(

)는 0도를 기준으로 그래프 상의 화살표에 표시된 범위를 벗어나지 않도록 제어하는 것이 바람직하다.Phase error between the first motor 200 and the second motor 210 (

) is large, synchronization between the first motor 200 and the second motor 210 may be released. Therefore, the phase error (

) is preferably controlled so as not to deviate from the range indicated by the arrow on the graph based on 0 degrees.

)가 증가하여 제2 모터(210)에 걸리는 토크(T_M2)가 최대값(T_M2.max)을 가지는 지점을 지나면, 제1 모터(200) 및 제2 모터(210) 간의 동기화가 해제된다. 따라서 토크(T_M2)가 최대값(T_M2.max)을 가지는 지점에서의 위상 오차(

)가 되기 전에 보상 전류를 더욱 증가시켜서 제1 모터(200) 및 제2 모터(210) 간의 동기화가 해제되는 것을 방지하는 것이 바람직하다. 따라서 임계값은 토크(T_M2)가 최대값(T_M2.max)을 가지는 지점에서의 위상 오차(

)와 일정한 마진을 두고 설정하는 것이 바람직하다. 즉, 임계값은 토크(T_M2)가 최대값(T_M2.max)을 가지는 지점에서의 위상 오차(

)의 80%의 값을 가지도록 설정될 수 있다. 즉, 임계값은 토크(T_M2)가 최대값(T_M2.max)을 가지는 지점에서의 위상 오차(

)와 20%의 마진을 가지도록 설정될 수 있다.In this case, the phase error (

) increases and the torque T _M2 applied to the second motor 210 passes a point having the maximum value T _M2.max , the synchronization between the first motor 200 and the second motor 210 is released . Therefore, the phase error at the point where the torque T _M2 has the maximum value T _M2.max (

), it is preferable to further increase the compensation current to prevent the synchronization between the first motor 200 and the second motor 210 from being released. Therefore, the threshold is the phase error at the point where the torque T _M2 has a maximum value T _M2.max

) and it is desirable to set it with a certain margin. That is, the threshold is the phase error at the point where the torque T _M2 has the maximum value T _M2.max

) can be set to have a value of 80% of That is, the threshold is the phase error at the point where the torque T _M2 has the maximum value T _M2.max

) and a margin of 20%.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various methods can be obtained by those skilled in the art within the scope of the technical spirit of the present invention. It is obvious that variations can be made. In addition, although the effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

100: motor control unit 110: inverter
120: control unit 121: speed estimation unit
122: compensation current setting unit 123: switching voltage control unit
123a: current command setting unit 123b: current command control unit
123c: voltage regulator 200: first motor
210: second motor

Claims (14)

an inverter for driving the first motor and the second motor using a plurality of switching elements; and
A control unit for controlling the inverter,
the control unit
a speed estimator for estimating a speed of the first motor using a current flowing through the first motor;
A phase error between the first motor and the second motor is estimated using a difference in current flowing through the first motor and the second motor and the speed of the first motor, and the phase error, a preset damping coefficient, and a threshold a compensation current setting unit for setting a compensation current using a value; and
And a switching voltage adjusting unit for adjusting the voltage applied to the switching element of the inverter by using the target speed, the speed of the first motor, and the compensation current,
When the phase error is equal to or less than the threshold value, the compensation current setting unit estimates a speed error between the first motor and the second motor using the phase error, and multiplies the phase error, the speed error, and the attenuation coefficient. set the compensation current,
The attenuation coefficient is initialized to an initially set value if the phase error is less than or equal to the threshold value, and is increased than the initially set value if the phase error is greater than the threshold value
motor control unit.
delete delete According to claim 1,
The compensation current setting unit sets the limit value as the compensation current when the compensation current is greater than the limit value
motor control unit.
According to claim 1,
The threshold value is a value set with a constant margin and a phase error between the first motor and the second motor so that the amount of change in torque applied to the second motor becomes 0
motor control unit.
According to claim 1,
The switching voltage regulator
a current command setting unit for setting a current command using the speed and target speed of the first motor; and
Further comprising a current command control unit for adjusting the current command by using the compensation current
motor control unit.
7. The method of claim 6,
The switching voltage regulator
Using the adjusted current command further comprising a voltage adjusting unit for adjusting the voltage applied to the switching element
motor control unit.
A method of controlling a motor including an inverter for driving a first motor and a second motor using a plurality of switching elements, the method comprising:
estimating the speed of the first motor using a current flowing through the first motor;
estimating a phase error between the first motor and the second motor using a difference in current flowing through the first motor and the second motor and a speed of the first motor;
setting a compensation current using the phase error, a preset attenuation coefficient, and a threshold value; and
Controlling the voltage applied to the switching element of the inverter by using the target speed, the speed of the first motor, and the compensation current,
The step of setting the compensation current is
estimating a speed error between the first motor and the second motor by using the phase error when the phase error is equal to or less than the threshold value; and
setting the compensation current by multiplying the phase error, the speed error, and the attenuation coefficient;
The attenuation coefficient is initialized to an initially set value if the phase error is less than or equal to the threshold value, and is increased than the initially set value if the phase error is greater than the threshold value
Motor control method.
delete delete 9. The method of claim 8,
The step of setting the compensation current is
If the compensation current is greater than the limit value, further comprising the step of setting the limit value to the compensation current
Motor control method.
9. The method of claim 8,
The threshold value is a value set with a constant margin and a phase error between the first motor and the second motor so that the amount of change in torque applied to the second motor becomes 0
Motor control method.
9. The method of claim 8,
The step of adjusting the voltage is
setting a current command using the speed and target speed of the first motor; and
using the compensation current to adjust the current command
Motor control method.
14. The method of claim 13,
The step of adjusting the voltage is
Controlling the voltage applied to the switching element by using the adjusted current command
Motor control method.

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