TWI641759B - Vacuum pump and operating method of the vacuum pump - Google Patents

Abstract

The present invention provides a vacuum pump that can reduce the frequency of operation stop caused by the occurrence of an error.

The vacuum pump of the present invention comprises: a pump module 1 for exhausting gas; a motor 2 for driving the pump module 1; an inverter device 5 for supplying variable frequency AC power to the motor 2; and a control device 7 The inverter device 5 is controlled. The inverter device 5 stops its own operation when an error caused by an overvoltage or an overcurrent occurs, and the control device 7 causes the inverter device 5 to be restarted as long as the occurrence of an error satisfies a predetermined condition.

Description

Vacuum pump and its operation method

The present invention relates to a vacuum pump that draws gas from a closed container such as a vacuum chamber, and more particularly to a vacuum pump having an inverter device having a protection function for preventing a failure caused by an overvoltage and/or an overcurrent. .

Dry vacuum pumps are widely used as manufacturing equipment for semiconductor components. In the manufacturing process of the semiconductor element, there is a step of processing the article in a vacuum space, and a dry vacuum pump is used to form the vacuum space.

The purpose of the dry vacuum pump is to change the operating speed in order to output the desired torque, or to save energy or control the pressure of the vacuum space. Generally, the inverter device is used for motor control. Some inverter devices have a protection function to protect themselves in order to avoid malfunctions caused by errors such as overvoltage and/or overcurrent. Once the inverter device of this type detects an error, the protection function is activated and its operation is stopped.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-127107

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2011-89428

However, once the dry vacuum pump suddenly stops operating in the production of the semiconductor element, the pressure in the vacuum space rises, and the product (semiconductor element) in production is damaged to cause defective products.

Accordingly, it is an object of the present invention to provide a vacuum pump and a method of operating the same that can reduce the frequency of operation stop caused by an error.

In order to achieve the above object, a first aspect of the present invention provides a vacuum pump comprising: a pump module for exhausting a gas; an electric motor for driving the pump module; and an inverter device for alternating frequency communication. The electric power is supplied to the electric motor; and the control device controls the inverter device, and the inverter device stops its own operation when an error caused by an overvoltage or an overcurrent occurs, and the control device is generated as long as the aforementioned error occurs. When the predetermined condition is satisfied, the aforementioned inverter device is restarted.

A second aspect of the present invention is a vacuum pump comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor And a control device that controls the inverter device, the aforementioned inverter device The operation is stopped when an error caused by an overvoltage or an overcurrent occurs, and the control device transmits an error release signal for canceling an error occurring within a predetermined period to the inverter device, the inverter When the device receives the error cancel signal, the device does not stop its own operation in the case where the aforementioned error occurs during the predetermined period.

A third aspect of the present invention is a vacuum pump comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor And a control device that controls the inverter device, the inverter device stops its own operation when an error occurs, and the control device restarts the inverter device after the operation of the inverter device is stopped. In the case where the number of errors occurring within the set time reaches a predetermined threshold value, the inverter device is not restarted.

A fourth aspect of the present invention is a method of operating a vacuum pump comprising: a pump module for exhausting a gas; an electric motor for driving the pump module; and an inverter device for alternating frequency communication Power is supplied to the motor; and a control device controls the inverter device, and the operation method of the vacuum pump stops the operation of the inverter device when an error caused by an overvoltage or an overcurrent occurs, as long as the aforementioned error The occurrence of the predetermined condition is met, and the inverter device is restarted.

According to a fifth aspect of the present invention, there is provided a method of operating a vacuum pump comprising: a pump module for exhausting a gas; an electric motor for driving the pump module; and an inverter device for variable frequency AC power is supplied to the aforementioned motor; and a control device controls the aforementioned inverter In the device, the operation method of the vacuum pump stops the operation of the inverter device when an error caused by an overvoltage or an overcurrent occurs, and transmits an error release signal for canceling an error occurring in a predetermined period to In the case where the above-described error occurs in the predetermined period of the inverter device, the operation of the inverter device is not stopped.

A sixth aspect of the present invention is a method of operating a vacuum pump comprising: a pump module for exhausting a gas; an electric motor for driving the pump module; and an inverter device for alternating frequency communication The electric power is supplied to the electric motor; and the control device controls the inverter device, and the operation method of the vacuum pump stops the operation of the inverter device when an error occurs, and causes the operation of the inverter device to stop after the operation of the inverter device is stopped. The inverter device is restarted, and in the case where the number of errors occurring within the set time reaches a predetermined threshold value, the inverter device is not restarted.

According to the first and fourth aspects of the present invention, when an error occurs under predetermined conditions, the inverter device is restarted. This predetermined condition is a condition that is expected to be an error that the inverter device does not malfunction even if the operation of the inverter device is continued. By such error monitoring, the frequency of stopping the operation of the pump caused by the occurrence of the error can be reduced.

According to the second and fifth aspects of the present invention, when an error occurs within a predetermined period, the error is automatically released and the inverter device does not stop. By such error monitoring, the frequency of stopping the operation of the pump caused by the occurrence of the error can be reduced.

According to the third and sixth aspects of the present invention, as long as the number of errors occurring within the set time does not reach the predetermined threshold value, the inverter device is immediately restarted even if the operation of the inverter device is stopped due to an error. By such error monitoring, the frequency of stopping the operation of the pump caused by the occurrence of the error can be reduced. Furthermore, each time an error occurs, any one of the plurality of timers starts measuring the time, so that the control device can quickly and surely detect that the error occurs at a high frequency.

1‧‧‧ pump module

2‧‧‧Electric motor

5‧‧‧Inverter device

7‧‧‧Control device

8‧‧‧Contained containers

9‧‧‧Power supply source

11‧‧‧Inverter Department

15‧‧‧Smoothing capacitor

12‧‧‧Inverter Division

13‧‧ ‧ brake driver

16‧‧‧Inverter Control Department

20‧‧‧Current measuring device

22‧‧‧ counter

23, 23A to 23E‧‧‧ timer

Fig. 1 is a schematic view showing a vacuum pump according to an embodiment of the present invention.

Figure 2 is a schematic diagram showing the inverter device.

Fig. 3 is a graph showing changes in the rotational speed of the motor when an error occurs when the motor is idling.

Fig. 4 is a graph showing changes in the rotational speed of the motor when an error occurs when the inverter device decelerates the motor in response to an instruction from the control device.

Fig. 5 is a view for explaining the operation of the counter for counting the number of counts and the timer for measuring the monitoring time.

Fig. 6 is a graph showing the inverter device in the error cancel mode during a predetermined period.

Fig. 7 is a schematic view showing a vacuum pump according to another embodiment of the present invention.

Figure 8 illustrates the action of the timer when the error occurs at a low frequency. Timing diagram.

Fig. 9 is a timing chart showing the operation of the timer when an error occurs at a high frequency.

Figure 10 is a timing diagram illustrating a method of using a timer to determine whether the number of errors occurring within a set time has reached a predetermined threshold.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a schematic view showing a vacuum pump according to an embodiment of the present invention. As shown in Fig. 1, the vacuum pump includes: a pump module 1 for exhausting gas; a motor 2 for driving the pump module 1; and an inverter device 5 for supplying variable frequency AC power to the motor 2 And a control device 7 that controls the inverter device 5.

The pump module 1 is connected to a sealed container 8 such as a vacuum chamber, and sucks the gas in the sealed container 8 to form a vacuum in the sealed container 8. The pump module 1 is a dry pump module that is formed without using oil in a flow path of a gas formed inside the pump module 1. A vacuum pump having such a dry pump module is generally referred to as a dry vacuum pump and is widely used in the manufacture of semiconductor components.

FIG. 2 is a schematic view of the inverter device 5. As shown in FIG. 2, the inverter device 5 includes an inverter unit 11, a smoothing capacitor 15, an inverter unit 12, a gate driver 13, and an inverter control unit 16. The inverter unit 11 has a rectifier circuit therein, and is configured to convert three-phase AC power supplied from the power supply source 9 into DC power. The smoothing capacitor 15 is provided to smooth the converted DC power.

The inverter unit 12 has a switching element such as an IGBT (Insulated Gate Bipolar Transistor), and generates three-phase AC power from the smoothed DC power. The gate driver 13 generates a gate driving signal for opening and closing each switching element of the inverter unit 12. The switching element of the inverter unit 12 is driven in accordance with a gate driving signal from the gate driver 13, whereby the inverter unit 12 outputs AC power of a variable frequency.

The current measuring device 20 measures the three-phase current output from the inverter unit 12, and sends the measured value of the three-phase current to the inverter control unit 16. The inverter control unit 16 controls the AC power output from the inverter unit 12 based on the measured value sent from the current measuring device 20 and the speed command value sent from the control device 7. In other words, the inverter control unit 16 receives the speed command value from the upper pump controller (not shown), and generates a PWM signal based on the measured value of the three-phase current. The PWM signal is sent to the gate driver 13. The gate driver 13 generates a gate driving signal for driving the switching elements of the inverter section 12 based on the PWM signal. The switching element of the inverter unit 12 is driven by the gate driving signal from the gate driver 13, whereby the inverter unit 12 outputs the variable frequency AC power to the motor 2.

The inverter device 5 is provided with a protection function for protecting itself from malfunctions when an error such as an overvoltage or an overcurrent occurs. More specifically, when the error occurs, the inverter device 5 stops its operation. The error can be roughly classified into an overvoltage error (that is, an excessive voltage is applied to the inverter device 5), and an overcurrent error (that is, an excessive current flows to the inverter device 5).

When the DC power input to the inverter unit 11 rises, the inverse The smoothing capacitor 15 inside the transformer device 5 and the switching elements of the inverter portion 12 may be damaged. Therefore, the inverter device 5 is configured to monitor the DC voltage of the inverter unit 11, and when the DC voltage is equal to or higher than the preset value, the inverter device 5 stops its operation.

The cause of the increase in the DC voltage of the inverter unit 11 is an abnormality of the power supply source 9 and an inverter control imbalance. Hereinafter, an overvoltage error caused by an abnormality in the power supply source 9 is referred to as error 1, and an overvoltage error caused by an inverter control offset is referred to as error 2.

Error 1 is caused by an abnormality in the supply of the alternating current power to the power supply source 9 of the inverter device 5. Error 1 will occur for a variety of reasons. When the error 1 occurs, the input voltage to the inverter device 5 rises, so the inverter device 5 may malfunction. Therefore, in this case, the inverter device 5 immediately stops its operation.

Error 2 is likely to occur after the motor 2 and the pump module 1 that are rotated by inertial force (ie, idling) are restarted after an instantaneous power failure. When an instantaneous power failure occurs, the power output of the inverter device 5 is automatically stopped (that is, the power is not input, so the inverter device 5 cannot output power). The length of the instantaneous power failure is usually within 1 second, so during the momentary power failure, the motor 2 will habitually continue to rotate, but the rotational speed of the motor 2 will gradually decrease due to loss of the bearing or the like.

When the power is restored, the inverter device 5 measures the rotational speed of the current motor 2 that is idling, and the inverter device 5 starts outputting the AC power having a frequency synchronized with the rotational speed of the motor 2. At this time, when the inverter device 5 outputs a frequency which corresponds to the rotational speed of the motor 2 When the AC power is lower, the inverter device 5 actively decelerates the motor 2, and the power of the motor 2 is returned to the inverter device 5 as regenerative energy. As a result, the voltage in the inverter device 5 rises and an overvoltage occurs.

When the power failure continues for a certain period of time, the motor 2 is completely stopped. Therefore, the operation of starting the inverter device 5 after a long power failure is no different from the normal startup operation, and the above-described error does not occur in this case.

Error 2 is also likely to occur when the inverter device 5 decelerates the motor 2 in accordance with an instruction from the control device 7. For example, when the vacuum pump is changed from the normal operation mode to the idle mode, the control device 7 instructs the inverter device 5 to lower the rotational speed of the motor 2. When the rotational speed of the motor 2 is actively reduced as described above, the power of the motor 2 may return to the inverter device 5 as regenerative energy. As a result, there is a case where the voltage in the inverter device 5 rises and an overvoltage occurs.

In addition to overvoltage, overcurrent may also be the cause of failure of the inverter device 5. That is, when a large current flows to the inverter device 5, the switching elements inside the inverter device 5 may be destroyed. Therefore, the inverter device 5 monitors the output current of the inverter unit 12, and when the output current is equal to or greater than the preset value, the inverter device 5 stops its operation.

The reason for the overcurrent is to consider the offset of the inverter control and the failure of the motor 2. Hereinafter, an overcurrent error caused by an inverter control offset is referred to as error 3, and an overcurrent error caused by a failure of the motor 2 is referred to as error 4.

Error 3 is like error 2, easy to make after an instantaneous power outage This occurs only when the motor 2 that is rotated by the inertial force is restarted or when the inverter device 5 decelerates the motor 2 in accordance with an instruction from the control device 7. For example, when the inverter device 5 is restarted after an instantaneous power failure, when the frequency of the AC power output from the inverter device 5 is greatly different from the actual rotation speed of the motor 2, it is controlled by the inverter. An overshoot produces an overcurrent. In particular, when the sensing of the rotor position of the motor 2 fails, the voltage is applied to the motor 2 at an unsuitable timing, and as a result, an overcurrent flows. The reason for the failure of the sensing of the rotor position is that the noise is overlapped with the detected current of the motor 2, or the load of the pump module 1 is rapidly changed, so that the rotational speed of the motor 2 is rapidly changed.

Furthermore, error 3 easily occurs when the pump module 1 (and the motor 2) is idling. The idling means an operation of rotating the motor 2 at an idling speed lower than the rated speed of the motor 2 in order to save energy. For example, in the idling, the motor 2 is rotated at a speed of 10% of the rated speed of the motor 2. The inverter device 5 is adjusted so that the motor 2 can rotate at its rated speed to perform appropriate speed control. The larger the difference between the idling speed and the rated speed is, the more unstable the control operation of the inverter control unit 16 is, and an overcurrent may flow.

Error 4 is an error caused by the failure of the motor 2. Therefore, when the error 4 occurs, the operation of the inverter device 5 must be immediately stopped, and the motor 2 can be repaired or replaced.

As described above, the errors of the inverter device 5 are roughly classified into overvoltage errors and overcurrent errors. In addition, the overvoltage error is divided into an error caused by an abnormality of the power supply source 9, and an inverter control imbalance is cited. Error 2, the overcurrent error is divided into error 3 caused by inverter control offset and error 4 caused by motor 2 failure. When these errors 1 to 4 occur, the inverter device 5 stops its operation and transmits an error signal to the control device 7.

Among the four errors 1 to 4, errors 1 and 4 are serious errors. In other words, if the operation of the inverter device 5 continues after the occurrence of the errors 1 and 4, the inverter device 5 may malfunction. Therefore, when errors 1 and 4 occur, it is necessary to stop the operation of the inverter device 5.

In contrast, errors 2 and 3 are mild errors. For example, as long as the rotational speed of the habitually rotating motor 2 is lowered and the regenerative energy is reduced, overvoltage and overcurrent do not occur. Further, even if the sensing of the rotor position fails, the sensing of the rotor position can be accurately performed at the next moment. These errors 2 and 3 are not caused by the failure of the inverter device 5 itself, but are caused by the control misalignment of the inverter device 5, and therefore it is not necessary to stop the operation of the inverter device 5.

Therefore, in order to avoid frequent operation and stop of the vacuum pump accompanying the error, the control device 7 is configured to immediately restart the inverter device 5 when the errors 2 and 3 occur.

When any of the errors 1 to 4 occurs, the error signal is sent from the inverter device 5 to the control device 7. Therefore, the control device 7 can detect the occurrence of an error by receiving the error signal. The control device 7 judges that the error is error 2 or error 3 when the occurrence of the error satisfies the predetermined condition, and causes the inverter device 5 to be restarted. The predetermined condition is the following three conditions.

Condition 1: An error occurs within a predetermined time from the power failure (instantaneous power failure) and re-supply of power (within 10 seconds, preferably within 5 seconds, preferably within 2 seconds).

Condition 2: occurs within a predetermined time (within 10 seconds, preferably within 5 seconds, more preferably within 2 seconds) from the time point when the inverter device 5 starts the deceleration of the motor 2 in accordance with an instruction from the control device 7. error.

Condition 3: The inverter device 5 causes an error when the motor 2 is rotated at an idle speed lower than its rated speed (less than 50% of the rated speed, preferably less than 30%, more preferably less than 10%).

When the occurrence of an error satisfies any of Condition 1, Condition 2, and Condition 3, the control device 7 causes the inverter device 5 to be restarted. On the other hand, when the occurrence of an error does not satisfy any of the conditions 1, 2, and 3, the error can be regarded as the above-mentioned errors 1 and 4. Therefore, the control device 7 does not restart the inverter device 5. The reason for setting the above conditions 1 to 3 is that, as described above, the errors 2 and 3 are likely to occur when the inverter device 5 is restarted after an instantaneous power failure, when the motor 2 is actively decelerated, and when the motor 2 is idling.

Fig. 3 is a graph showing changes in the rotational speed of the motor 2 when an error occurs when the motor 2 is idling. As shown in Fig. 3, when an error occurs when the motor 2 rotates at the idle speed, the inverter device 5 sends an error signal to the control device 7, and temporarily stops its operation. Since the occurrence of the error satisfies the condition 3, the control device 7 causes the inverter device 5 to be restarted. The motor 2 is rotated again before it is completely stopped, and the pump module 1 is continuously driven. Thus, even if an error occurs, the inverter device 5 continues its Since it is operated, the pump module 1 can continuously evacuate the vacuum of the container 8.

Fig. 4 is a graph showing changes in the rotational speed of the motor 2 when an error occurs when the inverter device 5 decelerates the motor 2 in response to an instruction from the control device 7. As shown in Fig. 4, when an error occurs in the inverter device 5 to decelerate the motor 2, the inverter device 5 sends an error signal to the control device 7, and temporarily stops its operation. Since the occurrence of the error satisfies the condition 2, the control device 7 causes the inverter device 5 to be restarted. As shown in FIG. 4, when an error occurs again within a predetermined time (within 10 seconds, preferably within 5 seconds, more preferably within 2 seconds) from the start of the restart of the inverter device 5, the control device 7 may also The inverter device 5 is again activated again.

Errors 2 and 3 are mild errors, but sometimes they can cause major failures if they occur frequently. Therefore, the control device 7 determines whether or not the operation of the inverter device 5 is continued or stopped based on the frequency of occurrence of the errors 2 and 3. More specifically, the control device 7 is configured to count the number of occurrences of an error (error 2 or error 3), and when the counted number of times reaches a predetermined critical value, the inverter device 5 is not restarted.

As shown in Fig. 1, the control device 7 includes a counter 22 for counting the number of errors and a timer 23 for measuring the monitoring time. When the control device 7 does not generate an error within a predetermined monitoring time, the counted number is reset to zero. This is because the occurrence of an error that does not occur within a predetermined monitoring time can be regarded as a low frequency of occurrence of errors 2 and 3.

Fig. 5 is a view for explaining the operation of the counter 22 for counting the number of counts and the timer 23 for measuring the monitoring time. When an error occurs (error 2 or error 3), counter 22 counts the number of occurrences of the error, the same The timer 23 starts counting. When the next error (Error 2 or Error 3) occurs, the counter 22 counts the number of occurrences of the error, and the timer 23 is reset to 0, and the timing is started again. When no error occurred during the predetermined monitoring time (10 seconds in Fig. 5), the number of counted errors was reset to zero.

When an error occurs again (error 2 or error 3), the counter 22 counts the number of occurrences of the error from 1 and the timer 23 starts counting. Repeating the count of the number of errors and the reset/start of the timer 23, when the counted number of errors reaches a predetermined threshold (three times in FIG. 5), even if an error occurs next, the control device 7 does not cause the inverter device 5 to start again. As a result, the supply of electric power to the motor 2 from the inverter device 5 is stopped, and the pump module 1 is also stopped.

An error that occurs before a predetermined monitoring time means that the frequency of the error occurs very frequently. Therefore, in this case, the control device 7 can protect the inverter device 5 from malfunction by not starting the inverter device 5 again.

Next, other embodiments of the present invention will be described. The configuration and operation of the present embodiment, which are not particularly described, are the same as those of the above-described embodiment, and the overlapping description thereof will be omitted. The control device 7 in the present embodiment is configured to transmit an error cancel signal for canceling an error generated in a predetermined period to the inverter device 5, and the reverse device 5 is configured to receive an error. When the signal is released, if an error occurs during the predetermined period, the operation is not stopped.

The predetermined time mentioned above is the following three periods.

Period 1: A period from a predetermined time (10 seconds, preferably 5 seconds, more preferably 2 seconds) from the power failure recovery and re-supply of power.

Period 2: A period from the time when the inverter device 5 starts deceleration of the motor 2 in response to an instruction from the control device 7, a predetermined time (10 seconds, preferably 5 seconds, more preferably 2 seconds) elapses.

Period 3: The inverter device 5 rotates the motor 2 at an idle speed lower than its rated speed (less than 50% of the rated speed, preferably less than 30%, more preferably less than 10%).

Fig. 6 is a graph for explaining that the inverter device 5 is in the error cancel mode in the periods 1, 2, and 3. The control device 7 transmits an error release signal to the inverter device 5 at the start of the above-described periods 1, 2, and 3. The inverter device 5 receives the error release signal and then cancels the error occurring during the periods 1, 2, and 3. According to the present embodiment, since the error is released, the inverter device 5 does not stop. Therefore, the rotation speed of the motor 2 can be prevented from falling, and the pump module 1 can maintain the vacuum pressure in the hermetic container 8.

An error occurring in the above periods 1, 2, and 3 can be regarded as the above error 2 or error 3. On the other hand, an error occurring outside the above-described periods 1, 2, and 3 can be regarded as the above-described error 1 or error 4. The error cancellation signal will only set the inverter device 5 to the error cancellation mode during the periods 1, 2, and 3. Therefore, when an error occurs in the period other than the periods 1, 2, and 3, the inverter device 5 stops its operation. .

Also in the present embodiment, the inverter device 5 transmits an error signal to the control device 7 every time an error occurs. Similarly to the above-described embodiment, the control device 7 is configured to count errors (error 2 or error). Error 3) The number of occurrences, and when no error occurs within a predetermined monitoring time (for example, 10 seconds), reset the counted number to 0, and when the counted number reaches a predetermined critical value, it will not The error release signal is transmitted to the inverter device 5. Therefore, when an error occurs after the counted number reaches a predetermined critical value, the error is not released, and the inverter device 5 stops its operation.

Fig. 7 is a schematic view showing a vacuum pump according to another embodiment of the present invention. The structure and operation of this embodiment which are not particularly described are the same as those of the embodiment shown in Fig. 1, and therefore the overlapping description thereof will be omitted. The inverter device 5 is configured to stop its own operation when an error occurs, and the control device 7 is configured to restart the inverter device 5 after the operation of the inverter device 5 is stopped. The types of errors include errors caused by overcurrent and errors caused by overvoltage. That is, regardless of the type of error, when an error occurs, the inverter device 5 stops its own operation.

As a result of the occurrence of an error, even if the operation of the inverter device 5 is stopped, the inverter device 5 is immediately activated again by the control device 7. Therefore, the rotation speed of the motor 2 can be prevented from falling, and the pump module 1 can maintain the vacuum pressure in the hermetic container 8. However, in the case where the error frequently occurs, if the inverter device 5 is forcibly started again, the inverter device 5 is likely to malfunction. Therefore, the control device 7 is configured not to restart the inverter device 5 when the number of errors occurring within the set time reaches a predetermined threshold value n. n is a natural number (n≧3) of 3 or more, which is set in advance.

As shown in Fig. 7, the control device 7 is provided with a plurality of timers 23 for measuring time. The number of these timers 23 is from the above pre The threshold value n is deducted by the value of 1, which is n-1. The plurality of timers are respectively configured to measure the time, and the measurement of the end time is performed when the measured time reaches the set time, and the measured time is reset to zero. The control device 7 is configured to activate any one of a plurality of timers each time an error occurs, and in the case where all of the plurality of timers are measuring time when an error occurs, the inverter device 5 is not re-introduced start up.

Fig. 8 is a timing chart for explaining the operation of the timer when an error occurs at a low frequency. In the example shown in Fig. 8, five timers 23A, 23B, 23C, 23D, and 23E are provided, and the set time is 10 minutes. The control device 7 (refer to Fig. 7) activates one of these timers 23A, 23B, 23C, 23D, 23E in a predetermined order every time an error occurs. In this example, when the error E1 occurs, the timer 23A is started, and the measurement of the time is started. When the error E2 occurs, the timer 23B is started, and the measurement of the time is started. Similarly, when errors E3, E4, and E5 occur, the timers 23C, 23D, and 23E are activated in this order.

The timers 23A to 23E measure the end time when the measured time reaches 10 minutes of the set time, and reset the measurement time to zero. Therefore, when the sixth error E6 occurs when the frequency of occurrence of the error is low, the time measurement operation of the first timer 23A has ended, and the timer 23A can start the measurement of the time again. As such, when an error occurs at a low frequency, any of the five timers 23A to 23E can start time measurement every time an error occurs.

On the other hand, Fig. 9 is a timing chart for explaining the operation of the timer when an error occurs at a high frequency. In this case, there are also five timings. The devices 23A to 23E are sequentially activated when the errors E1 to E5 occur. However, when the sixth error E6 occurs, the first timer 23A is still measuring the time. The other timers 23B to 23E also perform time measurement as well. Thus, when an error occurs at a high frequency, all the timers including the timer 23A have not ended the previous time measurement, and thus the measurement of the time cannot be started.

As can be understood from Fig. 9, when the error occurs, the timers 23 of the n-1 stations all measure the time, which means that n errors occur within the set time, that is, the error is occurring at a high frequency. Therefore, in this case, the control device 7 prevents the failure of the inverter device 5 from occurring before the inverter device 5 is restarted. On the other hand, as shown in Fig. 8, when the error occurs at a low frequency, the control device 7 causes the inverter device 5 to be immediately restarted to continue the operation of the pump module 1.

In the present embodiment, in order to determine whether or not the number of errors occurring within the set time has reached a predetermined threshold value, a plurality of timers 23 are employed. Although a timer can be used to determine whether the number of errors occurring within the set time has reached a predetermined threshold, by using a plurality of timers 23, the error can be quickly and surely detected to occur at a high frequency. Hereinafter, the advantages of using a plurality of timers 23 will be described with reference to FIGS. 9 and 10.

In the example shown in Fig. 9, the critical value of the number of occurrences of the error is set to 6. In other words, the allowable error occurs five times in the set time (10 minutes in Fig. 9), but when the error occurs six times, the control device 7 does not restart the inverter device 5. Figure 10 is an illustration of the use of a A timer diagram of a method for determining whether the number of errors occurring within a set time has reached a predetermined threshold. The example shown in Fig. 10 also sets the critical value of the number of occurrences of the error to 6.

As shown in Fig. 10, the timer repeatedly performs measurement of the set time (10 minutes in Fig. 10), and the control device 7 counts the number of errors occurring within the set time. Errors E1, E2, E3, and E4 occur within the initial set time. Therefore, the number of errors that occurred during the initial set time is 4, which is less than the critical value of 6. Errors E5, E6, E7, and E8 occur within the next set time. Therefore, the number of errors that occur within the next set time is also 4, which is less than the critical value of 6.

However, errors E2, E3, E4, E5, E6, and E7 occur within 10 minutes of the set time. This means that six errors occurred within 10 minutes. In the case where only one timer is used, the control device 7 sometimes cannot detect such a high frequency error occurrence.

On the other hand, according to the present embodiment shown in Fig. 9, each time an error occurs, any one of the plurality of timers 23A to 23E sequentially measures the time. Therefore, the control device 7 can quickly and surely detect an error occurring at a high frequency.

The above embodiments are described for the purpose of carrying out the invention by those having ordinary knowledge in the technical field to which the present invention pertains. Various modifications of the above-described embodiments can be understood by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the embodiments described, but should be construed as the maximum scope of the technical idea defined by the scope of the claims.

Claims (24)

A vacuum pump characterized by comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; the timer is measuring And a control device that controls the inverter device, wherein the inverter device stops its own operation when an error caused by an overvoltage or an overcurrent occurs, and the control device satisfies a predetermined condition as long as the occurrence of the error occurs. The inverter device is restarted before the motor is completely stopped, thereby continuing the operation of the pump module. The vacuum pump according to claim 1, wherein the predetermined condition is that an error occurs within a predetermined time from when the power is restored from the power failure and the power is re-supplied. The vacuum pump according to claim 1, wherein the predetermined condition is that an error occurs within a predetermined time from when the inverter device starts deceleration of the motor in response to an instruction from the control device. The vacuum pump according to claim 1, wherein the predetermined condition is that an error occurs when the inverter device rotates the motor at an idle speed lower than a rated speed thereof. Vacuum as described in any one of claims 1 to 4 a pump, wherein the control device counts the number of occurrences of the error, and resets the number of times of counting to 0 when the error does not occur within a predetermined monitoring time, and when the number of times of counting reaches a predetermined threshold value, The aforementioned inverter device is not restarted. A vacuum pump, comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; and a control device Controlling the inverter device, the inverter device stops its own operation when an error caused by an overvoltage or an overcurrent occurs, and the control device cancels an error cancellation signal that occurs during a predetermined period of time And transmitting to the inverter device, wherein when the error cancellation signal is received, the inverter device stops the operation of the pump in the case where the error occurs during the predetermined period, thereby continuing the pump module The operation. The vacuum pump according to claim 6, wherein the predetermined period is a period of time after a predetermined time elapses from the time when the power is restored and the power is re-supplied. The vacuum pump according to claim 6, wherein the predetermined period is a period from a time when the inverter device starts deceleration of the motor in accordance with an instruction from the control device. The vacuum pump according to claim 6, wherein the predetermined period is a period during which the inverter device rotates the motor at an idle speed lower than a rated speed. The vacuum pump according to any one of claims 6 to 9, wherein the control device counts the number of occurrences of the error, and when the error does not occur within a predetermined monitoring time, the number of times of counting is heavy. When it is set to 0, when the number of times of counting reaches a predetermined threshold value, the error cancel signal is not transmitted to the inverter device. A vacuum pump, comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; and a control device Controlling the inverter device, the inverter device stops its own operation when an error occurs, and the control device immediately restarts the inverter device after the operation of the inverter device is stopped, thereby continuing the pump When the module is operated and the number of errors occurring within the set time reaches a predetermined threshold value, the inverter device is not restarted. A vacuum pump, comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; The control device controls the inverter device, the inverter device stops its own operation when an error occurs, and the control device includes a plurality of timers for measuring time, and the number of the plurality of timers is equal to a predetermined number The threshold value deducts the value of 1, and the plurality of timers are respectively configured to measure the end time when the measured time reaches the set time, and the control device makes any of the plurality of timers each time an error occurs. One start, when an error occurs, when the plurality of timers are all performing the measurement of the time, the inverter device is not restarted. A method for operating a vacuum pump, comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; And a control device for controlling the inverter device, wherein the operation method of the vacuum pump stops the operation of the inverter device when an error caused by an overvoltage or an overcurrent occurs, as long as the aforementioned error occurs When the predetermined condition is satisfied, the inverter device is restarted before the motor is completely stopped, thereby continuing the operation of the pump module. A method of operating a vacuum pump according to claim 13 of the patent application, In the foregoing predetermined condition, an error occurs within a predetermined time from the resumption of power supply from the power failure recovery. The method of operating a vacuum pump according to claim 13, wherein the predetermined condition is that a predetermined time period from a time point when the inverter device starts deceleration of the motor according to an instruction from the control device error. The method of operating a vacuum pump according to claim 13, wherein the predetermined condition is that an error occurs when the inverter device rotates the motor at an idle speed lower than a rated speed thereof. The method of operating a vacuum pump according to any one of claims 13 to 16, wherein the number of occurrences of the error is counted, and when the error does not occur within a predetermined monitoring time, the number of times of counting is heavy. When it is set to 0, when the number of times of the aforementioned counting reaches a predetermined critical value, the inverter device is not restarted. A method for operating a vacuum pump, comprising: a pump module for exhausting gas; an electric motor for driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; and controlling The device controls the inverter device, and the operation method of the vacuum pump is such that when an error caused by an overvoltage or an overcurrent occurs When the operation of the inverter device is stopped, an error release signal for canceling an error occurring in a predetermined period is transmitted to the inverter device, and in the case where the error occurs during the predetermined period, the foregoing is not caused. The operation of the inverter device is stopped, thereby continuing the operation of the pump module. The method of operating a vacuum pump according to claim 18, wherein the predetermined period is a period of time after a predetermined time elapses from a time when the power is restored and the power is re-supplied. The method of operating a vacuum pump according to claim 18, wherein the predetermined period is a predetermined time period from when the inverter device starts deceleration of the motor in response to an instruction from the control device. Period. The method of operating a vacuum pump according to claim 18, wherein the predetermined period is a period during which the inverter device rotates the motor at an idle speed lower than a rated speed. The method of operating a vacuum pump according to any one of the preceding claims, wherein the number of times of the occurrence of the error is counted, and when the error does not occur within a predetermined monitoring time, the number of times of counting is heavy. When it is set to 0, when the number of times of counting reaches a predetermined threshold value, the error cancel signal is not transmitted to the inverter device. A method of operating a vacuum pump, the vacuum pump having: a pump module for exhausting gas; an electric motor for driving the pump module; an inverter device for supplying variable frequency AC power to the motor; and a control device for controlling the inverter device, When the operation method of the vacuum pump is an error, the operation of the inverter device is stopped, and after the operation of the inverter device is stopped, the inverter device is immediately restarted, thereby continuing the operation of the pump module. In the case where the number of errors occurring within the set time reaches a predetermined threshold value, the inverter device is not restarted. A vacuum pump operating method, the vacuum pump comprising: a pump module for exhausting gas; an electric motor driving the pump module; and an inverter device for supplying variable frequency AC power to the motor; and a control device Controlling the inverter device, the operation method of the vacuum pump is to stop the operation of the inverter device when an error occurs, and the control device includes a plurality of timers for measuring time, and the number of the plurality of timers Equivalent to deducting a value of 1 from a predetermined threshold value, wherein the plurality of timers are respectively configured to measure the end time when the measured time reaches the set time, and each time an error occurs, any one of the plurality of timers is used. One When the error occurs, when the plurality of timers are all performing the measurement of the execution time, the inverter device is not restarted.