TWI525254B - A vacuum apparatus preventing the stall control - Google Patents

Description

Vacuum device for preventing stall control

The present disclosure is a vacuum apparatus and method, and more particularly to a vacuum apparatus and method for preventing stall control.

In the servo drive system, the performance of the servo motor is very important. The performance of the servo motor is related to the resolution of the encoder. The higher the resolution, the better the performance of the servo motor speed control and positioning control.

At present, the design of high-efficiency servo drive system is mainly based on permanent magnet brushless motor. In the vacuum pump equipment, there is no way to install the encoder, so no sensing control technology is generated, because there is no encoder feedback motor angle. Data, angle must rely on non-sensing control technology to estimate the angle. In the vacuum pump system, the motor load is related to the speed. The higher the speed, the higher the load. Therefore, there is a special specification in the application. It will increase instantaneously and exceed the maximum operating current of the servo motor. Therefore, it is necessary to reduce the speed and maintain the output torque at the maximum operating current of the motor. If the system load changes instantaneously, the angle estimation will change, and the sensing control technology will not be changed. There must be a corresponding mechanism to match the instantaneous change of the load to reduce the speed and maintain the output torque at the maximum operating conditions, otherwise the angle estimation will be diverged and the vacuum pump system will stall.

In the implementation of high-performance servo motors, there are certain specifications for the requirements of positioning control and variable frequency. Therefore, most of the application environments will be equipped with encoders or resolvers, and the sensor position feedback sensor on the other hand. The performance of the servo drive system has a certain correlation with the encoder. High-performance servo motors are also equipped with encoder resolutions.

In addition, there are also servo motor drive systems that also have sensors that do not install position feedback. Some applications of this type are based on cost considerations, and there is also a system that does not require positioning control. The speed control is mainly used as a vacuum pump. The application is exemplified because, for the sake of airtightness or in the case of an axial compressor, the fluid is corrosive or has other considerations, there is no way to install the encoder, so the position-free sensing control technology is used, and the motor is used. The angle is obtained by means of estimation. Because there is no position to feedback the angle of use estimation, there is no way for the bandwidth response to be compared with the position feedback control system, so the response to load changes will be slower. Therefore, you need to pay attention to this phenomenon when using positionless sensing control.

In the application of the vacuum pump, the motor output torque is related to the motor speed, usually the higher the torque required for the higher speed, and the vacuum pump operating specifications, when the vacuum is broken, to maintain the same maximum speed, The required torque will be much larger than the rated operating point of the motor. Therefore, it is necessary to reduce the rotational speed to reduce the output torque. However, while reducing the rotational speed, the output torque of the motor must be maintained at the rated working point. If the conventional drive control architecture is not satisfied, With this limitation, and when positionless sensing control is used, a stalled state occurs due to its lower bandwidth.

In an embodiment, the present disclosure provides a vacuum device for preventing stall control, which has a feedback function, including: a stall control unit, the fifth end is connected with a speed command; and a higher limiter is Its third end The seventh end of the feedback unit connected to the stall control, the fourth end of which outputs a torque command to an intermediate control unit, when the input of the higher limiter is greater than 0 and lower than a second threshold, The input value of the higher limiter increases linearly with the output value, and when the input of the higher limiter is greater than a second threshold, the output of the higher limiter is a second highest limit positive value; a motor connected to the intermediate control unit, the motor is controlled by the intermediate control unit to generate a rotational torque of the vacuum device for preventing stall control, and a speed feedback of the motor returns the stall control via the intermediate control unit The sixth end of the unit; wherein the stall control unit of the stall control increases the load of the motor when the vacuum is broken, and the feedback unit of the stall control automatically controls the rotation torque of the motor to decrease and maintains no more than the rated working point; When the feedback control unit of the stall control returns to the vacuum by the vacuum, the load of the motor decreases. The feedback unit of the stall control automatically controls the rotational torque of the motor and returns to the rotational torque when the vacuum is restored. And maintain no more than the rated working point.

The present disclosure provides a vacuum apparatus for preventing stall control, which has a feedback function, as shown in FIG. 1, including: a stall control unit 31, a higher limiter 16, and a motor 19. a stall control feedback unit 31, the fifth end 25 is connected to the speed command; a higher limiter 16, the third end 23 is connected to the seventh end of the stall control feedback unit 31, and the fourth end 24 thereof Outputting a torque command to an intermediate control unit 20, when the input of the higher limiter 16 is greater than 0 and lower than a second threshold, the input value of the higher limiter 16 increases linearly with the output value. When the input of the higher limiter 16 is greater than a second threshold, the output of the higher limiter 16 A second highest limit positive value is output; and a motor 19 is coupled to the intermediate control unit 20, and the motor 19 is controlled by the intermediate control unit 20 to generate a rotational torque of the vacuum device for preventing stall control, the motor 19 The one speed feedback is returned to the sixth end 26 of the stall control feedback unit 31 via the intermediate control unit 20; wherein the stall control feedback unit 31, when the vacuum is broken, the motor 19 load rises, the stall The controlled feedback unit 31 automatically controls the rotational torque drop of the motor 19 to maintain no more than the rated operating point; wherein the stall control unit 31, when the vacuum is returned to the vacuum, the load of the motor 19 drops, the stall The controlled feedback unit 31 automatically controls the rotational torque of the motor 19, returns to the rotational torque during vacuum, and maintains no more than the rated operating point.

The stall control unit 31 of the present disclosure includes, as shown in FIG. 1 , a lower limiter 15 , a third adder 13 , a compensator 11 , a first adder 14 , and a second adder . 17. A first integrator 18 and a comparator 12.

The first end 21 of the lower limiter 15 is an input end, and the seventh end 27 of the feedback unit 31 via the stall control is connected to the third end 23 of the higher limiter 16, the lower limiter 15 The second end 22 is an output end. When the input of the lower limiter 15 is greater than 0 and lower than a first threshold, the input value of the lower limiter 15 increases linearly with the output value, when the lower limit When the input of the limiter 15 is greater than a first threshold, the output of the lower limiter 15 is a first highest limit positive value.

The third adder 13 is connected to the first end 21 and the second end 22 of the lower limiter 15, and the second end 22 of the lower limiter 15 outputs a signal minus the input signal of the first end 21, and the generated signal is generated. The third adder 13 is input. a compensator 11 for receiving the output signal of the third adder 13; a first adder 14 via the 5th end 25 of the feedback unit 31 of the stall control and the speed command The first adder 14 is connected to the compensator 11, wherein the first adder 14 adds the speed command to the output signal of the compensator 11; a second adder 17 is The intermediate control unit 20 is connected via the sixth end 26 of the stall control feedback unit 31, and the intermediate control unit 20 returns the speed feedback to the second adder 17, the first adder 14 commands the speed The signal added to the output signal of the compensator 11 is sent to the second adder 17, and the second adder 17 adds all the signals input to the second adder 17, and then generates the second addition. The output signal of the device 17, wherein the speed feedback is a negative value; a first integrator 18 is coupled to the second adder 17, and receives an output signal generated by the second adder 17, the first The integrator 18 is coupled to the first end 21 of the lower limiter 15; and a comparator 12 is coupled to the first integrator 18, Receiving the output signal of the first integrator 18, the comparator 12 is connected to the compensator 11, and the output signal of the comparator 12 is transmitted to the compensator 11, when the comparator 12 is less than the rated operating point, The output of the comparator 12 is 1, and when the comparator 12 is greater than and equal to the nominal operating point, the output of the comparator 12 is zero.

The compensator 11 as shown in FIG. 2 includes a return gain unit 52, a multiplier 55, an integrated negative comparator 51, a fourth adder 56, an integral gain unit 53, and a A proportional gain unit 54, a fifth adder 58, a second integrator 57, and an output limiter 59. The recovery gain unit 52 is connected to the comparator 12 and receives the output value of the comparator 12; the multiplier 55 is connected to the return gain unit 52. When the output value of the comparator 12 is 1, the output value of the return gain unit 52 is input to the multiplier 55. When the output value of the comparator 12 is 0, the output value of the return gain unit 52 is not input. The multiplier 55; an integral negative comparator 51, when the value of the integrated negative comparator 51 is less than 0, the output value of the integrated negative comparator 51 is 1, when the integral negative comparator 51 is input. When the value of the value is greater than or equal to 0, the output value of the integrated negative comparator 51 is 0; a fourth adder 56, the output value of the return gain unit 52 and the output value of the integrated negative comparator 51 are multiplied by The multiplier 55 is multiplied and output to the fourth adder 56. The integral gain unit 53 is connected to the third adder 13, and the output value of the third adder 13 is output to the integral gain unit 53, and the integral is obtained. The gain unit 53 is connected to the fourth adder 56, and the output value of the integral gain unit 53 is output to the fourth adder 56; a proportional gain unit 54, which is connected to the third adder 13, The output value of the third adder 13 is input to the proportional gain unit 54; a fifth adder 58 The proportional gain unit 54 is connected to the fifth adder 58 and is output from the output of the proportional gain unit 54 to the fifth adder 58; a second integrator 57, the fourth adder 56 and the second integral The controller 57 is connected, and the output value of the fourth adder 56 is input to the second integrator 57. The output value of the second integrator 57 is output to the fifth adder 58, the fourth adder 56, and The integrated negative value comparator 51, the output value end of the second integrator 57 is connected to the fifth adder 58, the fourth adder 56, and the integrated negative value comparator 51, wherein the multiplier 55, The integral gain unit 53 and the output values of the second integrator 57 are summed and sent to the fourth adder 56; and the output limiter 59 is connected to the fifth adder 58 when the output Limiter 59 When the input value is lower than a third critical negative value, the output value of the output limiter 59 is a lowest output negative value, and when the input value of the output limiter 59 is higher than a third critical negative value and lower than 0. The output value of the output limiter 59 increases linearly with the input value. When the input value of the output limiter 59 is greater than or equal to 0, the output limit of the output limiter 59 is equal to 0. The output limiter The output value of 59 is input to the first adder 14.

The feedback control unit 31 of the stall control increases the load of the motor 19 when the vacuum is broken. At the first time point (T1), as shown in FIG. 3, the horizontal axis represents time and the vertical axis represents the rotational speed of the motor. The rotation speed of the motor 19 is instantaneously decreased, and the speed is fed back to a negative value, and is output to the second adder 17, and then output to the higher limiter 16 via the first integrator 18 to output the torque command. Below the second highest limit positive value of the higher limiter 16, at the second time point (T2), the rotational speed of the motor 19 is controlled to rise by the intermediate control unit 20, and is maintained not to exceed the rated operating point. When the vacuum is broken, at the second time point (T2), after the rotation speed of the motor 19 is controlled via the intermediate control unit 20, the negative value of the speed feedback is gradually decreased, and is output from the first integrator 18 to The input value of the lower limiter 15 is gradually increased. When the input value of the lower limiter 15 is accumulated higher than the fourth threshold, the vacuum device for preventing the stall control is gradually entered from the second time point (T2). At the third time point (T3), the output value of the lower limiter 15 is limited to the first highest limit positive value, and after the output value of the lower limiter 15 is subtracted from the input value of the lower limiter 15, After the third adder 13 is added up, a negative value is generated and output to the compensator 11. Wherein the fourth threshold is selected from one of 65% to 85% of the rated operating point.

From the 2nd time point (T2), gradually enter the 3rd time point (T3), when the comparison When the input value of the low limiter 15 is accumulated higher than the fourth threshold, the comparator 12 outputs 0, and controls the output of the return gain unit to be 0 and the output via the multiplier 55 is 0. The third adder 13 adds up a negative value to the integral gain unit 53 of the compensator 11 and the proportional gain unit 54, and the negative value of the second integrator 57 is output to the fourth adder 56. Negative value, at this time, the output of the multiplier 55 is 0 by the input of the fourth adder 56, the negative value of the second integrator 57 is output to the fourth adder 56, and a negative value and the integral gain unit are The output of 53 is negative, and finally a negative value is output to the fifth adder 58, and the output of the output limiter 59 is a negative value, and the compensator 11 outputs a negative value to the first adder. 14.

From the second time point (T2), gradually entering the third time point (T3), when the input value of the lower limiter 15 is accumulated higher than the fourth threshold, the compensator 11 outputs a negative value and the speed. After the command is added, it is output to the first adder 14 to generate a deceleration action of the rotation of the motor 19. At this time, the vacuum device for preventing the stall control gradually enters the fourth time point (T4) from the third time point (T3). The input value of the lower limiter 15 is cumulatively higher than the fourth threshold and gradually enters below the fourth threshold.

From the 4th time point (T4), gradually entering the 5th time point (T5), when the input value of the lower limiter 15 is accumulated below the 4th threshold, the comparator 12 outputs 1 and controls the The output value of the reply gain unit is a positive value. If the value in the second integrator 57 is a negative value, the output of the integrated negative value comparator 51 is 1, and the output value of the return gain unit is output via the multiplier 55. And after the output of the integrated negative comparator 51 is a product of 1, the output of the multiplier 55 is generated to be positive to the fourth adder 56, at which time the comparator 12 When the output is 1, the output value of the third adder 13 is 0, and the output of the integral gain unit 53 is 0, and the proportional gain unit 54 is 0, so the sum of the inputs of the fourth adder 56 is positive. After the value is further summed back by the second integrator 57, the output of the second integrator 57 is gradually increased from a negative value to a positive value, and is output to the output limiter 59 via the fifth adder 58, the output The limiter 59 input is gradually increased from a negative value to a positive value, and the output of the output limiter 59 is gradually increased from a negative value to an output upper limit 0 of the limiter, and the compensator 11 gradually outputs a negative value to 0. The compensator 11 outputs a value to the first adder 14.

From the 4th time point (T4), gradually entering the 5th time point (T5), when the input value of the lower limiter 15 is accumulated below the 4th threshold, the compensator 11 gradually outputs a negative value to 0, and the output value of the compensator 11 is added to the first adder 14 and the speed command is summed, and the rotational speed of the motor 19 is gradually restored to the rated operating point.

In the vacuum state, the vacuum is applied via the motor 19, and after entering the fifth time point (T5), the rotation speed of the motor 19 is restored to the rated operating point due to the limitation of the higher limiter 16.

As shown in FIG. 4, it is a schematic diagram of the current of the motor 19 which recovers the vacuum to the vacuum, wherein the horizontal axis is time and the vertical axis is motor 19 current.

The above description is only intended to describe the preferred embodiments or embodiments of the present invention, which are not intended to limit the scope of the invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

11‧‧‧Compensator

12‧‧‧ comparator

13‧‧‧3rd Adder

14‧‧‧1st adder

15‧‧‧Lower limiter

16‧‧‧High limiter

17‧‧‧2th Adder

18‧‧‧First integrator

19‧‧‧Motor

20‧‧‧Intermediate control unit

21‧‧‧1st end

22‧‧‧2nd end

23‧‧‧3rd end

24‧‧‧4th end

25‧‧‧5th

26‧‧‧6th end

27‧‧‧7th

31‧‧‧Stop control unit for stall control

51‧‧‧Integral Negative Comparator

52‧‧‧Response gain unit

53‧‧‧Integral Gain Unit

54‧‧‧Proportional Gain Unit

55‧‧‧Multiplier

56‧‧‧4th Adder

57‧‧‧Second integrator

58‧‧‧5th Adder

59‧‧‧Output limiter

T1‧‧‧1st point

T2‧‧‧2nd time

T3‧‧‧3rd point

T4‧‧‧4th time

T5‧‧‧5th time

Figure 1 Schematic diagram of a vacuum device to prevent stall control.

Figure 2 Schematic diagram of the compensation gas.

Figure 3 Schematic diagram of the motor speed at which the vacuum is restored to vacuum.

Figure 4 Schematic diagram of the motor current from vacuum recovery to vacuum.

11‧‧‧Compensator

12‧‧‧ comparator

13‧‧‧3rd Adder

14‧‧‧1st adder

15‧‧‧Lower limiter

16‧‧‧High limiter

17‧‧‧2th Adder

18‧‧‧First integrator

19‧‧‧Motor

20‧‧‧Intermediate control unit

21‧‧‧1st end

22‧‧‧2nd end

23‧‧‧3rd end

24‧‧‧4th end

25‧‧‧5th

26‧‧‧6th end

27‧‧‧7th

31‧‧‧Stop control unit for stall control

Claims (17)

A vacuum device for preventing stall control, comprising: a stall control unit with a stall control, wherein the fifth end is connected to the speed command; and a higher limiter, the third end of which is connected to the seventh of the feedback unit of the stall control a fourth end thereof outputs a torque command to an intermediate control unit; and a motor coupled to the intermediate control unit, the intermediate control unit controls the motor to generate a rotational torque of the vacuum device for preventing stall control a speed feedback of the motor is returned to the sixth end of the stall control feedback unit via the intermediate control unit; wherein the stall control unit returns to the vacuum and the motor load decreases. The stall control unit automatically controls the rotational torque of the motor, returns to the rotational torque during vacuum, and maintains no more than the rated operating point; wherein the stall control feedback unit includes: a lower limiter, a first end input end of the lower limiter, the seventh end of the feedback unit via the stall control being connected to the third end of the higher limiter; a third adder, the third adder system Connected to the first end and the second end of the lower limiter; a compensator receiving the output signal of the third adder; a first adder, the first adder is back via the stall control The fifth end of the granting unit is connected to the speed command, and the first adder is connected to the compensator, wherein the first adder adds the speed command to the output signal of the compensator; a second adder connected to the intermediate control unit via a sixth end of the stall control feedback unit; a first integrator coupled to the second adder to receive the second adder Output signal, the first integrator is connected to the first end of the lower limiter; and a comparator is connected to the first integrator to receive the output signal of the first integrator, Comparing the comparator with the compensator, and transmitting the output signal of the comparator to the compensator; wherein the compensator comprises: a return gain unit, wherein the return gain unit is connected to the comparator Accepting the output value of the comparator; a multiplier, the multiplier is connected to the return gain unit; and an integral negative comparator, when the value of the integrated negative comparator is less than 0, the integral is negative The output value of the value comparator is 1, when the value of the integrated negative comparator is greater than or equal to 0, the output value of the integrated negative comparator is 0; a fourth adder, the output value of the return gain unit And the output value of the integrated negative comparator is in the multiplier After multiplying, output to the fourth adder; an integral gain unit, the integral gain unit is connected to the third adder, and the output value of the third adder is input to the integral gain unit, and the integral gain unit is Connecting the fourth adder, the output value of the integral gain unit is output to the fourth adder; a proportional gain unit, the integral gain unit is connected to the third adder, and the output value of the third adder is Transmitted to the proportional gain unit; a fifth adder, the proportional gain unit is connected to the fifth adder, and the output value of the proportional gain unit is input to the fifth adder; a second integrator, the fourth adder and the second adder The integrator is connected, and the output value of the fourth adder is input to the second integrator, and the output value of the second integrator is output to the fifth adder, the fourth adder, and the integral negative value is compared. The output end of the second integrator is coupled to the fifth adder, the fourth adder, and the integrated negative comparator, wherein the multiplier, the integral gain unit, and the second integrator The output values are summed and sent to the fourth adder; and an output limiter is connected to the fifth adder, when the input value of the output limiter is lower than a third When the critical value is negative, the output value of the output limiter is a minimum output negative value. When the input value of the output limiter is higher than a third critical negative value and lower than 0, the output value of the output limiter is Linearly increasing with the input value, when the input value of the output limiter is greater than or equal to 0, Limiter output value output lines is equal to 0, the output value of the limiter input to the output of the first adder. A stall prevention control method for a vacuum apparatus according to claim 1, comprising: the higher limiter 4th end outputs a torque command to an intermediate control unit; the intermediate control unit controls the motor to generate the vacuum device Rotational torque; the speed feedback of the motor is returned via the intermediate control unit The sixth end of the feedback control unit of the stall control; and the feedback unit of the stall control, when the vacuum is returned to the vacuum, the motor load is decreased, and the feedback unit of the stall control automatically controls the rotational torque of the motor and recovers Rotating torque to vacuum and maintaining no more than the rated operating point. A method for preventing stall control for a vacuum apparatus according to claim 2, wherein the input of the higher limiter is input when the input of the higher limiter is greater than 0 and lower than a second threshold The value and the output value increase linearly. When the input of the higher limiter is greater than a second threshold, the output of the higher limiter is a second highest limit positive value. A method for preventing stall control for a vacuum device according to claim 3, wherein the stall control unit of the stall control increases the load of the motor when the vacuum is broken, and the feedback unit of the stall control automatically controls the The rotational torque of the motor is reduced and maintained no more than the rated operating point. A method for preventing stall control of a vacuum apparatus according to claim 4, wherein the feedback unit of the stall control is returned to the vacuum by a vacuum, the motor load is decreased, and the stall control is fed back. The unit automatically controls the rotational torque of the motor, returns to the rotational torque during vacuum, and maintains no more than the rated operating point. A method for preventing stall control for a vacuum device according to claim 5, comprising: receiving the output signal of the third adder, the first adder is the speed command and the compensation The output signals of the device are added, the first integrator receives the output signal generated by the second adder, and the comparator receives the output signal of the first integrator, and the output of the comparator The signal is transmitted to the compensator; and the second limit output of the lower limiter is the input of the lower limiter when the input of the lower limiter is greater than 0 and lower than a first threshold The value and the output value increase linearly. When the input of the lower limiter is greater than a first threshold, the output of the lower limiter is a first highest limit positive value. A method for preventing stall control for a vacuum apparatus according to claim 6, wherein the intermediate control unit returns the speed feedback to the second adder, the first adder and the speed command The signal added by the output signal of the compensator is sent to the second adder, and the second adder adds all the signals input to the second adder, and then generates an output signal of the second adder, wherein This speed feedback is a negative value. A method for preventing stall control for a vacuum device according to claim 7, wherein when the comparator is less than a rated operating point, the output of the comparator is 1, and the comparator is greater than and equal to the rated operating point. The output of the comparator is 0. A method for preventing stall control for a vacuum device according to claim 8 includes: the return gain unit accepts an output value of the comparator; an output value of the return gain unit and the integral negative comparator The output value is multiplied in the multiplier and output to the fourth adder; when the value of the integrated negative comparator is less than 0, the output value of the integrated negative comparator is 1, when the integral is input When the value of the negative comparator is greater than or equal to 0, the output value of the integrated negative comparator is 0; when the input value of the output limiter is lower than a third critical negative value The output limit value of the output limiter is a minimum output negative value, and when the input value of the output limiter is higher than a third critical negative value and lower than 0, the output value of the output limiter is related to the input The value increases linearly. When the input value of the output limiter is greater than or equal to 0, the output value of the output limiter is equal to 0, and the output value of the output limiter is output to the first adder; when the comparator is When the output value is 1, the output value of the return gain unit is input to the multiplier, and when the output value of the comparator is 0, the output value of the return gain unit is not input to the multiplier. A method for preventing stall control of a vacuum apparatus according to claim 9, wherein the feedback unit of the stall control increases the load of the motor when the vacuum is broken, and the motor rotates at the first time. The speed is instantaneously decreased, the speed is fed back to a negative value, and is output to the second adder, and then output to the higher limiter via the first integrator, so that the output of the torque command is lower than the higher limiter The second highest limit positive value is controlled at the second time point by the intermediate control unit to increase the rotational speed of the motor and to maintain the rated operating point. A method for preventing stall control of a vacuum apparatus according to claim 10, wherein, at the second time point, after the vacuum is broken, the speed is increased after the rotation speed of the motor is controlled via the intermediate control unit. The negative value is gradually decreased, and the input value outputted by the first integrator to the lower limiter is gradually increased. When the input value of the lower limiter is accumulated higher than the fourth threshold, the stall prevention control is prevented. When the vacuum device gradually enters the third time point from the second time point, the output value of the lower limiter is limited to the first highest limit positive value, and the output value of the lower limiter is decreased. After the input value of the lower limiter is added by the third adder, a negative value is generated and input to the compensator. A method for preventing stall control for a vacuum apparatus according to claim 11, wherein the fourth threshold value is one selected from the range of 65% to 85% of the rated operating point. A method for preventing stall control for a vacuum apparatus according to claim 12, wherein from the second time point, gradually entering the third time point, when the input value of the lower limiter is accumulated higher than the fourth At the limit value, the comparator output is 0, and the output of the feedback gain unit is controlled to be 0, and the output of the multiplier is 0. At this time, the third adder is summed to generate a negative value and is input to the compensator. The integral gain unit and the proportional gain unit are outputted by the negative value of the second integrator to a negative value of the fourth adder, and the output of the multiplier is 0 by the input of the fourth adder. The negative value of the second integrator is output to a negative value of the fourth adder and an output negative value of the integral gain unit, and finally a negative value is output to the fifth adder, and then the output limiter is The output is a negative value and a negative value is output by the compensator to the first adder. A method for preventing stall control for a vacuum apparatus according to claim 13, wherein from the second time point, gradually entering the third time point, when the input value of the lower limiter is accumulated higher than the fourth time At the limit value, the compensator outputs a negative value and adds the speed command to the first adder to generate a deceleration effect of the motor rotation. At this time, the vacuum device for preventing the stall control is caused by the third time point. Gradually entering the 4th time point, the input value of the lower limiter is accumulated from the fourth threshold and gradually falls below the fourth threshold. A method for preventing stall control for a vacuum apparatus according to claim 14, wherein from the fourth time point, gradually entering the fifth time point, when the input value of the lower limiter is accumulated lower than the fourth When the limit is set, the output of the comparator is 1, and the output value of the return gain unit is controlled to be a positive value. If the value in the second integrator is a negative value, the output of the integrated negative comparator is 1. After the multiplication device outputs the output of the gain unit and the output of the integrated negative comparator to 1, the output of the multiplier is positive to the fourth adder, and when the output of the comparator is 1 The output value of the third adder is 0, and the output value of the integral gain unit is 0, and the proportional gain unit is 0, so the sum of the input 4th adder is positive, and then the second integral is passed. After the controller loops up, the output of the second integrator is gradually increased from a negative value to a positive value, and is output to the output limiter via the fifth adder, and the output limiter input is gradually increased from a negative value to a positive value. And the output of the output limiter gradually increases from a negative value to the limit The output of the controller is limited to 0, and the compensator gradually outputs a negative value to 0, and the compensator outputs a value to the first adder. A method for preventing stall control for a vacuum apparatus according to claim 15, wherein from the fourth time point, gradually entering the fifth time point, when the input value of the lower limiter is accumulated lower than the fourth At the limit value, the compensator gradually outputs a negative value to 0, and after the compensator output value is added to the first adder and the speed command, the motor rotation speed is gradually restored to the rated operating point. A method for preventing stall control for a vacuum apparatus according to claim 16, wherein the vacuum is applied, and the vacuum is applied via a motor. After entering the 5th time point, the motor rotation speed is restored to the rated operating point due to the limitation of the higher limiter.