KR102086242B1 - Method for controlling flux weakening of IPMSM for high speed elevator - Google Patents

Abstract

The present invention relates to a method for controlling a weak-flux operation of a motor used in high-speed elevator driving and, more specifically, to a method for controlling a weak-flux operation, which uses a low-pass filter instead of an integrator to calculate a current modulation instruction value in a weak-flux operation mode of an embedded permanent magnet synchronous motor so as to reduce torque pulsation generated at the time of switching from a maximum torque-per-unit power operation mode to the weak-flux operation mode, and initializes and sets the current modulation instruction value in accordance with a motor driving mode of either driving the motor as a motor or as a generator in the weak-flux operation mode to reduce vibration generated by the motor in accordance with the motor driving mode.

Description

Method for controlling flux flux of motor for high speed operation of elevator

The present invention relates to a method for controlling weak magnetic flux operation of an electric motor used for driving a high speed elevator. More specifically, in a weak magnetic flux driving mode of an embedded permanent magnet synchronous motor, a low pass filter is used instead of an integrator to calculate a current modulation command value per unit power. The torque pulsation generated at the time of switching from the maximum torque (MTPA) running mode to the weak magnetic flux running mode can be reduced, and the current modulation command depends on whether the motor is driven by a motor or a generator in the weak magnetic flux running mode. The present invention relates to a method of controlling weak magnetic flux that can reduce vibration generated in an electric motor according to an electric motor driving mode.

Typically, an embedded permanent magnet synchronous motor (IPMSM) is a synchronous motor in which a permanent magnet is inserted into a rotor core, and has excellent high speed durability and high driving performance for industrial and hybrid electric vehicles. It is suitable for use as a motor.

There is always a current phase where the torque generated for the same current is maximum, and the maximum torque per unit current (MTPA: Maximum) is to drive the embedded permanent magnet synchronous motor at the operating point where the maximum torque is always generated for the armature current. Torque per Ampere).

In order to drive the embedded permanent magnet synchronous motor used in an elevator at high speed, the output torque of the motor driven by the inverter is limited by the maximum voltage and current that the inverter can supply to the motor. To operate the motor beyond the rated operating range, the inverter is required to synthesize the voltage along the operating point to achieve the maximum speed of the motor and apply it to the motor.

As the speed of the motor increases, the voltage and current that the inverter can supply to the motor are limited, so the voltage of the inverter must be controlled so as not to saturate to maximize the output of the motor operating at high speed. As such, driving the embedded permanent magnet synchronous motor so as to reduce the magnetic flux of the motor and prevent the voltage of the inverter from saturating when operating at high speed is called a weak magnetic flux operation mode.

In the conventional weak flux operation mode, an integrator is used to calculate a current modulation command value required to move an operating point capable of achieving the maximum speed of the motor. However, when calculating the current modulation command value using the integrator, there is a problem that the torque pulsation of the motor occurs when the transition from the maximum torque operation mode per unit power to the weak magnetic flux operation mode.

It is an object of the present invention to provide a weak magnetic flux driving control method capable of reducing torque pulsation generated at the time of switching from the maximum torque driving mode per unit power to the weak magnetic flux operating mode during high speed driving of an embedded permanent magnet synchronous motor. .

Another object of the present invention is to provide a weak magnetic flux driving control method for selectively initializing the current modulation command value based on whether the motor is driven in the weak magnetic flux driving mode.

Another object of the present invention is to provide a weak magnetic flux driving control method that can reduce the occurrence of vibration by initializing the current modulation command value in the weak magnetic flux driving mode according to whether the motor is driven by a motor or a generator. will be.

In order to achieve the object of the present invention, the weak magnetic flux driving control method according to the present invention is a voltage magnitude required to drive the motor to the operating point that can achieve the maximum speed of the motor and a voltage magnitude applied to the motor, which can be generated by the inverter Calculating the difference between the voltages, passing the voltage difference through a low pass filter to remove noise included in the voltage difference, and applying a direction gain to the voltage difference passing through the low pass filter to obtain a current modulation command value. Calculating and limiting a voltage applied to the motor in the high speed operation of the motor based on the current modulation command value.

Here, the current modulation command value (M _d , M _q ) is calculated as follows.

는 전압 차이(

)를 저역 통과 필터에 통과시킨 값이며, (X_{d ,} X_{q )}는 일정 크기의 토크 곡선에서 일정 토크 벡터를 의미하며, X는 일정 토크 벡터의 크기이며, α는 가중치인 것을 특징으로 한다. here

Is the voltage difference (

) Is a value passed through the low pass filter, (X _{d ,} X _{q )} is a constant torque vector in a torque curve of a constant size, X is a magnitude of a constant torque vector, α is characterized in that the weight.

The final current command value for limiting the magnitude of the voltage applied to the motor in the weak magnetic flux driving control method according to the present invention is a current modulation command to the current command value in the maximum torque per unit current (MTPA) operating mode It is characterized by calculating the sum of the values.

In the weak magnetic flux driving control method according to the present invention, when the current modulation command value is larger than 0 in the running mode of the maximum torque per unit current, the current modulation command value is initialized to 0.

The weak magnetic flux driving control method according to the present invention is characterized in that when the motor is driven by a motor, the d-axis current modulation command value M _d and the q-axis current modulation command value M _q are respectively controlled to 0 or less.

In the weak magnetic flux driving control method according to the present invention, when the motor is driven by a generator, the d-axis current modulation command value M _d is controlled to 0 or less, and the q-axis current modulation command value M _q is controlled to 0 or more. It is done.

The weak magnetic flux driving control method according to the present invention has the following effects.

First, the weak magnetic flux driving control method according to the present invention calculates a current modulation command value using a low pass filter instead of an integrator, so that the weak magnetic flux driving mode in the maximum torque operation mode per unit power during high-speed operation of the embedded permanent magnet synchronous motor It is possible to reduce the torque pulsation generated at the time of switching.

Second, the weak magnetic flux driving control method according to the present invention by initializing the current modulation command value to 0 when the motor is not driven in the weak magnetic flux driving mode based on whether the motor is driven in the weak magnetic flux driving mode, per unit current Allow the motor to run in full torque running mode.

Third, the weak magnetic flux driving control method according to the present invention initializes the current modulation command value according to the motor driving mode of whether the motor is driven by a motor or a generator in the weak magnetic flux driving mode, the motor according to the motor driving mode The vibration generated can be reduced.

1 is a functional block diagram for explaining a weak magnetic flux driving control apparatus according to the present invention.
2 is a functional block diagram for explaining an example of the current command value calculation unit according to the present invention.
3 is a flowchart illustrating a method of controlling weak magnetic flux driving according to the present invention.
Figure 4 shows a torque curve of a certain magnitude in the current axis.
5 is a flowchart illustrating an example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.
6 is a flowchart illustrating another example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.
7 is a flowchart illustrating another example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.

Technical terms used in the present invention are merely used to describe particular embodiments, it should be noted that it is not intended to limit the present invention. In addition, the technical terms used in the present invention should be interpreted as meanings generally understood by those skilled in the art unless the present invention is defined in any other meaning in the present invention, and is excessively comprehensive. It shall not be construed in the sense of or in the sense of being excessively reduced. In addition, when the technical terminology used in the present invention is an incorrect technical term that does not accurately express the spirit of the present invention, it should be understood as being replaced by a technical term that can be properly understood by those skilled in the art.

Also, the singular forms used in the present invention include the plural forms unless the context clearly indicates otherwise. In the present invention, terms such as “consisting of” or “comprising” are not to be construed as necessarily including all of the various components or steps described in the invention, and some of the components or some of the steps are included. It should be construed that it may not be, or may further include additional components or steps.

In addition, it should be noted that the accompanying drawings are only for easily understanding the spirit of the present invention and should not be construed as limiting the spirit of the present invention by the accompanying drawings.

Hereinafter, the weak magnetic flux driving control method of the motor according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a functional block diagram for explaining a weak magnetic flux driving control apparatus according to the present invention.

,

)과 전류 변조 지령값으로부터 인버터부(150)의 출력 전압을 제한하기 위한 최종 전류 지령값(

,

)을 계산한다. 전류 제어부(130)는 최종 전류 지령값으로부터 인버터부(150)로 인가되는 d축 전압 지령값(

)과 q축 전압 지령값(

)을 생성한다. 전동기(170)는 인버터부(160)에서 변환된 전원에 의해 구동된다.Referring to Figure 1 in more detail, the current command value calculation unit 110 is the current command value (calculated in the maximum torque (MTPA) controller (not shown) per unit power (

,

) And the final current command value for limiting the output voltage of the inverter unit 150 from the current modulation command value (

,

Calculate The current controller 130 controls the d-axis voltage command value applied to the inverter unit 150 from the final current command value (

) And q-axis voltage command value (

). The electric motor 170 is driven by the power converted by the inverter unit 160.

Meanwhile, the motor mode determination unit 180 determines the motor driving mode according to whether the motor is driven by a motor or a generator, and the weak magnetic flux control unit 190 determines a current command value calculator based on the determined motor driving mode ( The current command value calculation unit 110 is initialized and controlled by the current modulation command value calculated in 110 or the motor 170 is driven in the maximum torque per unit power (MTPA) driving mode or the weak magnetic flux driving mode. Initial control of current modulation command value calculated in

2 is a functional block diagram for explaining an example of the current command value calculation unit according to the present invention.

)와 인버터에서 합성 가능한, 전동기로 인가되는 전압 크기(

) 사이의 전압 차이(△V)를 계산한다.Referring to Figure 2 in more detail, the subtraction unit 111 is a driving voltage that can give the maximum speed of the motor to the voltage required to drive the motor (

) And the magnitude of the voltage applied to the motor,

Calculate the voltage difference (ΔV) between

The low pass filter 113 removes noise existing in the calculated voltage difference, and the multiplier 117 multiplies the direction gain calculated by the gain calculator 115 to obtain a current modulation command value M _d , M _q . Calculate Here, the gain calculator 115 calculates a direction gain including a direction in which the torque of the motor can be reduced.

,

)을 계산한다.The final command value calculation unit 119 sums the current command value calculated by the MTPA controller per unit power to the current modulation command value calculated by the multiplication unit 117 to determine the final current command value (

,

Calculate

Preferably, the final command value calculator 119 may initialize the current modulation command value based on a control signal received from the weak magnetic flux control unit when calculating the final current command value. That is, the weak magnetic flux control unit generates a control signal for initializing and setting the current modulation command value calculated according to whether the motor is driven in the weak magnetic flux driving mode or the maximum torque driving mode per unit power, or in the motor driving mode. Generates a control signal for initializing the current modulation command value calculated according to, the final command value calculation unit 119 calculates the final current command value by initializing the current modulation command value according to the control signal of the weak magnetic flux control unit. .

3 is a flowchart illustrating a method of controlling weak magnetic flux driving according to the present invention.

)와 인버터에서 합성 가능한, 전동기로 인가되는 전압 크기(

) 사이의 전압 차이(△V)를 아래의 수학식(1)과 같이 계산한다(S100).Referring to Figure 3 in more detail, the voltage magnitude required to drive the motor to the operating point that can achieve the maximum speed of the motor (

) And the magnitude of the voltage applied to the motor,

Is calculated as shown in Equation 1 below (S100).

[Equation 1]

Here, V _dc means a DC link voltage applied to the inverter unit.

)을 생성한다(S200).The calculated voltage difference is passed through a low pass filter to remove noise included in the voltage difference.

) Is generated (S200).

)에 방향 이득을 적용하여 전류 변조 지령값(M_d, M_q)을 아래의 수학식(2)와 수학식(3)과 같이 계산한다(S300).Voltage difference through low pass filter (

) And the current modulation command values M _d and M _q are calculated as in Equations (2) and (3) below (S300).

[Equation 2]

[Equation 3]

Here, (X _{d ,} X _q ) means a constant torque vector in a torque curve of a predetermined size, X is the size of the constant torque vector, α is characterized in that the weight.

Torque (T _e) of the interior permanent magnet synchronous motor is expressed as shown in Equation (4) below.

[Equation 4]

Where λ _f is the magnetic flux of the permanent magnet, L _ds and L _dq are the d-axis inductance and q-axis inductance of the stationary coordinate system of the motor, and P is the number of poles of the motor.

The direction in which the torque increases in the maximum torque driving mode per unit power is expressed as in Equation 5 below.

[Equation 5]

The constant torque direction in the constant torque curve shown in FIG. 4 is perpendicular to the direction of increasing torque. Therefore, the direction of the constant torque curve is expressed as in Equation 6 below.

[Equation 6]

Referring to FIG. 3 again, the final current command value is calculated as shown in Equation (7) below to limit the voltage applied to the motor in the high speed operation of the motor based on the current modulation command value (S400).

[Equation 7]

5 is a flowchart illustrating an example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.

Referring to FIG. 5 in more detail, it is determined whether the electric motor is driven in a maximum torque per unit power (MTPA) driving mode or in a weak magnetic flux driving mode (S411).

When the motor is driven in the maximum torque per unit power (MTPA) running mode, it is determined whether the current modulation command value is greater than zero (S413). In the maximum torque per unit power (MTPA) operation mode in which voltage saturation does not occur, the weak magnetic flux control should not be applied. When the current modulation command value is greater than zero, the current modulation command value is initialized to 0 (S415).

The final current command value is calculated by summing the current modulation command value and the current command value (S417).

6 is a flowchart illustrating another example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.

Looking in more detail with reference to Figure 6, whether the motor is driven by a motor or a generator to determine the driving mode of the motor (S431). Here, the case where the motor is configured by the motor and the case when the motor is driven by the generator may be determined based on the direction of the power output from the motor.

When the motor is driven by the motor (S433), it is determined whether the d-axis current modulation command value M _d is greater than zero or the q-axis current modulation command value M _q is greater than zero (S435).

When the d-axis current modulation command value (M _d ) is greater than zero or the q-axis current modulation command value (M _q ) is greater than zero, the d-axis current modulation command value (M _d ) is initialized to 0 or the q-axis current is set. The modulation command value M _q is initialized to 0 (S437).

The final current command value is calculated by summing the current modulation command value and the current command value (S439).

7 is a flowchart illustrating another example of calculating a final current command value in the weak magnetic flux driving control method according to the present invention.

Looking more specifically with reference to Figure 7, whether the motor is driven by a motor or a generator to determine the driving mode of the motor (S451).

When the motor is driven by a generator (S453), it is determined whether the d-axis current modulation command value M _d is greater than zero (S454).

When the d-axis current modulation command value M _d is greater than zero, the d-axis current modulation command value M _d is initialized to 0 (S455).

On the other hand, when the q-axis current modulation command value M _q is smaller than 0, the q-axis current modulation command value M _q is initialized and set to 0 (S457).

The final current command value is calculated by summing the current modulation command value and the current command value (S459).

As described above, the current modulation command value is initialized to 0 by dividing the case of driving the motor from the motor and the case of the generator, thereby reducing the occurrence of vibration of the motor in the weak magnetic flux running mode.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may include a magnetic storage medium (eg, ROM, floppy disk, hard disk, etc.), an optical reading medium (eg, CD-ROM, DVD, etc.) and a carrier wave (eg, the Internet). Storage medium).

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

110: current command value calculation unit 130: current control unit
150: inverter unit 170: electric motor
180: electric motor mode determination unit 190: weak magnetic flux control unit
111: subtraction part 113: low pass filter part
115: gain calculation unit 117: multiplication unit
119: final command value calculation unit

Claims (6)

In the weak magnetic flux driving control method for high speed operation of the motor,
Calculating a voltage difference between a voltage magnitude required for driving the motor to an operating point capable of achieving the maximum speed of the motor and a voltage magnitude applied to the motor, which can be generated by an inverter;
Passing the voltage difference through a low pass filter to remove noise included in the voltage difference;
Calculating a current modulation command value by applying a direction gain to the voltage difference passed through the low pass filter; And
Limiting the voltage applied to the motor in the high speed operation of the motor based on the current modulation command value,
The current modulation command value (M _d , M _q ) is generated by the following equation (1),
[Equation 1]

Is the voltage difference (

) Is the value passed through the low pass filter, (X _d, X _q ) means a constant torque vector in the torque curve, X is the magnitude of the constant torque vector, α is a weight,
Wherein the direction gain is to reduce the torque of the motor, the direction of the constant torque vector is weak magnetic flux running control method, characterized in that perpendicular to the direction in which the torque increases. delete According to claim 1, wherein in the weak magnetic flux driving control method
The final current command value for limiting the magnitude of the voltage applied to the motor is calculated by adding the current modulation command value to the current command value in the maximum torque per unit current (MTPA) operating mode. How to control the weak flux operation. The method of claim 3, wherein in the weak magnetic flux driving control method
And the current modulation command value is set to 0 when the current modulation command value is greater than zero in the driving mode of the maximum torque per unit current. The method of claim 3, wherein the weak magnetic flux driving control method
And d-axis current modulation command value (M _d ) and q-axis current modulation command value (M _q ), respectively, when the motor is driven by a motor. The method of claim 3, wherein the weak magnetic flux driving control method
And d-axis current modulation command value (M _d ) is controlled to 0 or less and q-axis current modulation command value (M _q ) is controlled to 0 or more when the motor is driven by a generator.

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