CN103711697B - Dry vacuum pump device and control device used in the dry vacuum pump - Google Patents

Abstract

The invention provides a dry vacuum pump device and a control device used in the dry vacuum pump device, which can stably operate without causing a motor and an inverter to break down when a load is increased. A dry vacuum pump device (1) is provided with at least 1 pump unit and a control device (5) for controlling the pump unit, wherein the pump unit is provided with a dry vacuum pump (2), a motor (3) for driving the dry vacuum pump (2), and an inverter (4) for controlling the rotating speed of the motor (3), the control device (5) has a function of switching an output current limit value of the inverter (4) from a 1 st current limit value to a 2 nd current limit value, the 1 st current limit value is a continuous rated current value which is the maximum value of current which can be continuously flowed to the motor (3) by the inverter (4), and the 2 nd current limit value is a value exceeding the continuous rated current value.

Description

Dry vacuum pump device and control device used in the dry vacuum pump

technical field

The present invention relates to a dry vacuum pump device and a control device used in the dry vacuum pump.

Background technique

Generally, a dry vacuum pump device includes a dry vacuum pump, a motor that drives the dry vacuum pump, an inverter that controls the rotational speed (rotation frequency) of the motor, and a control device that controls the operation of the inverter. Dry vacuum pumps are sometimes used to exhaust the gas in the vacuum chamber of semiconductor manufacturing equipment, but depending on the type of gas, products (reaction products) may be generated due to chemical reactions. When such gas is discharged, a product may be generated in the pump, and the product may enter the pump rotor. In addition, products adhering to the inner wall of the vacuum chamber may peel off and enter the pump rotor. As a result, the rotational speed of the pump decreases.

There is a so-called load-lock system vacuum exhaust system in which a load-lock chamber is provided between the vacuum chamber and the pump. The load lock chamber is a small space for reducing the pressure from the atmospheric pressure to the vacuum and raising the pressure from the vacuum to the atmospheric pressure when moving wafers into and out of the vacuum chamber that maintains the vacuum. The vacuum chamber is in principle always under vacuum. It is a load lock vacuum chamber that enables wafer transfer between the vacuum space in the vacuum chamber and the atmospheric pressure space. Wafers are processed in a vacuum chamber, and shortening the time for entering and exiting wafers into and out of the vacuum chamber is related to an overall increase in throughput. Therefore, there is a need to rapidly evacuate the gas within the load lock chamber in which a vacuum is formed. However, when the load-lock vacuum chamber is evacuated from atmospheric pressure to vacuum, an overload may be applied to the motor and the rotation speed of the motor may decrease, thereby reducing the exhaust speed of the pump.

In order to maintain the rotational speed of the pump when such an overload is applied to the motor, it is necessary to use a large-capacity motor. Therefore, in semiconductor manufacturing equipment and the like, a motor with a larger capacity than that required for normal operation is selected and used.

Contents of the invention

The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a dry vacuum pump device capable of stably operating with a small-capacity motor even when the load increases. Another object of the present invention is to provide a control device used in such a dry vacuum pump device.

In order to achieve the above object, an aspect of the present invention is a dry vacuum pump device having at least one pump unit and a control device for controlling the pump unit, wherein the pump unit has: a dry vacuum pump; a motor of a type vacuum pump; and an inverter for controlling the rotational speed of the motor, the control device has a function of switching the output current limit value of the inverter from a first current limit value to a second current limit value, and the The first current limit value is a continuous rated current value that is a maximum value of current that the inverter can continuously flow to the motor, and the second current limit value is a value exceeding the continuous rated current value.

A preferred aspect of the present invention is characterized in that the output current limit value of the inverter is switched from the first current limit value to the 2nd current limit value.

A preferred aspect of the present invention is characterized in that the control device is characterized in that when the rotation speed of the dry vacuum pump is lower than a predetermined target rotation speed when the inverter outputs a current corresponding to the first current limit value, , switching the output current limit value of the inverter from the first current limit value to the second current limit value.

A preferred aspect of the present invention is characterized in that the control device switches the output current limit value of the inverter from the second current limit value to the first current limit value.

A preferred aspect of the present invention is characterized in that the control device changes the output current limit value of the inverter from the second current limit value to The second current limit value is switched to the first current limit value.

A preferred aspect of the present invention is characterized in that at least one temperature sensor for measuring the temperature of the pump unit is further provided, and the control device switches the inverter pump unit when the temperature measured by the temperature sensor exceeds a predetermined threshold. The output current limit value of the switch is switched from the second current limit value to the first current limit value.

A preferred aspect of the present invention is characterized in that the at least one temperature sensor is selected from a temperature sensor that measures the temperature of the pump housing of the dry vacuum pump, a temperature sensor that measures the temperature of the bearings of the dry vacuum pump, and a temperature sensor that measures the temperature of the dry vacuum pump. A temperature sensor for the temperature of the motor, a temperature sensor for measuring the temperature of the pump rotor of the dry vacuum pump, a temperature sensor for measuring the temperature of the suction gas of the dry vacuum pump, and a temperature sensor for measuring the temperature of the exhaust gas of the dry vacuum pump Temperature Sensor.

A preferred mode of the present invention is characterized in that the at least one pump unit is a main pump unit that discharges gas at atmospheric pressure and a booster pump unit that discharges gas at vacuum pressure, so that the power supplied to the dry vacuum pump device does not exceed Operate the main pump and the booster pump at a preset value.

Another aspect of the present invention is a control device used in a dry vacuum pump device including a dry vacuum pump, a motor for driving the dry vacuum pump, and an inverter for controlling the rotational speed of the motor, wherein the The control device has a function of switching the output current limit value of the inverter from a first current limit value to a second current limit value at which the inverter can continuously flow to the motor. The maximum value of the current is a continuous rated current value, and the second current limit value is a value exceeding the continuous rated current value.

A preferred aspect of the present invention is characterized in that the control device changes the output current limit value of the inverter from the first current limit value in accordance with a command from an external command device provided outside the dry vacuum pump device. switch to the 2nd current limit value.

A preferred aspect of the present invention is characterized in that the control device is characterized in that when the rotation speed of the dry vacuum pump is lower than a predetermined target rotation speed when the inverter outputs a current corresponding to the first current limit value, , switching the output current limit value of the inverter from the first current limit value to the second current limit value.

A preferred aspect of the present invention is characterized in that the control device switches the output current limit value of the inverter from the second current limit value to the first current limit value.

A preferred aspect of the present invention is characterized in that the control device changes the output current limit value of the inverter from the second current limit value to The second current limit value is switched to the first current limit value.

According to the present invention, when the load is heavy, the output current limit value of the inverter is temporarily switched to the second current limit value, whereby the dry vacuum pump can be operated stably while maintaining the rotational speed.

Description of drawings

FIG. 1 is a diagram showing a vacuum exhaust system including a dry vacuum pump device according to a first embodiment of the present invention.

Fig. 2 is a sectional view of a dry vacuum pump and a motor.

Fig. 3 is a sectional view taken along line III-III of Fig. 2 .

Fig. 4 is a sectional view taken along line IV-IV of Fig. 2 .

Fig. 5 is a diagram showing a control procedure of the dry vacuum pump device.

Fig. 6 is a diagram showing a location where a temperature sensor is arranged in a pump unit.

FIG. 7 is a diagram showing switching between a first current limit value and a second current limit value.

FIG. 8 is a diagram showing an example of operation control of a dry vacuum pump.

FIG. 9 is a diagram for explaining judgment of switching of an output current limit value.

(a) of FIG. 10 is a graph showing the relationship between the output power of the inverter and the motor speed when the output current limit value of the inverter is set to the first current limit value, and (b) of FIG. 10 ) is a graph showing the relationship between the output current of the inverter and the rotational speed of the motor, and (c) of FIG. 10 is a graph showing the relationship between the output voltage of the inverter and the rotational speed of the motor.

(a) of FIG. 11 is a graph showing the relationship between the output power of the inverter and the rotational speed of the motor when the output current limit value of the inverter is set to the second current limit value, and (b) of FIG. 11 ) is a graph showing the relationship between the output current of the inverter and the motor rotation speed, and (c) of FIG. 11 is a graph showing the relationship between the output voltage of the inverter and the motor rotation speed.

Fig. 12 is a diagram showing another example of a vacuum evacuation system including a dry vacuum pump device.

13 is a schematic diagram of a pump device according to a second embodiment of the present invention.

14 is a schematic diagram showing a state where a host controller is connected to a control device as an external command device instead of an operation panel.

Fig. 15 is a diagram schematically showing a system of the pump device shown in Figs. 13 and 14 .

FIG. 16 is a diagram showing an example of operation control of a booster pump and a main pump.

(a) of FIG. 17 is a graph showing the relationship between the output power of the inverter of the main pump unit and the motor speed during the priority operation of the booster pump, and (b) of FIG. 17 is a graph showing the output power of the inverter of the main pump unit. As a graph of the relationship between the output current and the motor rotation speed, (c) of FIG. 17 is a graph showing the relationship between the output voltage of the inverter of the main pump unit and the motor rotation speed.

(a) of FIG. 18 is a graph showing the relationship between the output power of the inverter of the boost pump unit and the motor speed when the boost pump is preferentially operated, and (b) of FIG. 18 shows the inverter of the boost pump unit. 18( c ) is a graph showing the relationship between the output voltage of the inverter of the booster pump unit and the motor speed.

Explanation of reference signs

1. 90 pump unit

2 pumps

3, 103, 107 motor

4, 104, 108 Inverter

5 Controls

7 commercial power supply

8, 130 intake pipe

9.131 Exhaust pipe

11 vacuum chamber

12 Connection piping

13 flow sensor

14, 120 Pump temperature sensor

20, 121 pump casing

21 pump rotor

22 Rotor housing

23 axis of rotation

24, 25, 123 bearings

27 timing gear

28 gearbox

30 Motor housing

35 Motor rotor

36 permanent magnet

37 stator core

39 pole teeth

40, 126 Coils

41 Host controller

42, 122 Bearing temperature sensor

43, 124 Rotor temperature sensor

44, 125 Motor temperature sensor

45, 127 intake air temperature sensor

46, 128 Exhaust gas temperature sensor

50 load lock vacuum chamber

51 connecting pipe

52 gate valve

53 Suction valve

92 booster pump unit

93 Main pump unit

102 booster pump

106 main pump

110 Controls

111 Intake pipe

115 Operation panel

detailed description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a vacuum exhaust system including a dry vacuum pump device according to a first embodiment of the present invention. The vacuum exhaust system has a dry vacuum pump device 1 and a vacuum chamber 11 connected to the dry vacuum pump device 1 . As shown in FIG. 1 , a dry vacuum pump device 1 includes a pump 2 , a motor 3 for driving the pump 2 , an inverter 4 for controlling the rotation speed of the motor 3 , and a control device 5 for controlling the operation of the inverter 4 . The pump 2 is a dry vacuum pump that does not use oil in the gas flow path. One pump unit is composed of pump 2 , motor 3 and inverter 4 . The control device 5 has a central processing unit (CPU) built in it, and is connected to the inverter 4 through a communication signal transmission unit or contacts. The dry vacuum pump device 1 is connected to a commercial power supply 7 . The intake pipe 8 of the pump 2 and the vacuum chamber 11 are connected by a connection pipe 12 , and the gas in the vacuum chamber 11 is discharged from the exhaust pipe 9 of the pump 2 through the connection pipe 12 by the operation of the pump 2 .

A flow sensor 13 for measuring the flow rate of gas flowing into the pump 2 is attached to the intake pipe 8 . The measured flow rate of the gas is converted into a flow rate signal by the flow sensor 13 and sent to the control device 5 . A pump temperature sensor 14 for measuring the temperature of the pump 2 is attached to the pump 2 . The measured temperature of the pump 2 is converted into a temperature signal by the pump temperature sensor 14 and sent to the control device 5 . Furthermore, the temperature signal obtained by the pump temperature sensor 14 is sent from the control device 5 to the host controller 41 described later.

FIG. 2 is a sectional view of the pump 2 and the motor 3 . The pump described in this embodiment is a Roots-type vacuum pump, but other types of vacuum pumps such as screw-type vacuum pumps may be selected instead of the Roots-type vacuum pump. As shown in FIG. 2 , a plurality of pump rotors (Roots rotors) 21 are arranged in the pump housing 20 . The pump rotor 21 is housed in a rotor case 22 , and a slight gap is formed between the pump rotor 21 and the rotor case 22 . The pump rotor 21 is fixed to the rotating shaft 23 . Although not shown, another pump rotor is arranged in parallel to the pump rotor 21 , and this pump rotor is also fixed to a rotating shaft (not shown). The rotating shaft 23 is rotatably supported by bearings 24 and 25 . A pair of timing gears 27 meshing with each other are provided at one end of the rotating shaft 23 and housed in a gear case 28 . The motor 3 is provided at the other end of the rotating shaft 23 .

A specific structure of the motor 3 will be described with reference to FIGS. 3 and 4 . Fig. 3 is a sectional view taken along line III-III of Fig. 2 . As shown in FIG. 3 , a pair of motor rotors 35 and 35 are accommodated in the motor case 30 . The outer peripheral surfaces of the motor rotors 35 , 35 are formed by permanent magnets 36 , 36 , and the stator core 37 is provided so as to surround the motor rotors 35 , 35 .

Fig. 4 is a sectional view taken along line IV-IV of Fig. 2 . As shown in FIG. 4 , the stator core 37 inside the motor case 30 has magnetic pole teeth 39 arranged so as to surround the motor rotors 35 , 35 . A coil 40 is wound around each magnetic pole tooth 39 . When a current flows through the coil 40 , a magnetic field is formed on the magnetic pole teeth 39 , and the motor rotors 35 , 35 are rotated by the magnetic field.

Driven by the motor 3 , the pump rotors rotate in opposite directions to each other, and the gas in the vacuum chamber 11 is blocked between the pump rotor and the rotor case 22 and moved to the exhaust pipe 9 . By continuously performing such gas transfer, the gas in the vacuum chamber 11 is evacuated.

Next, the control procedure of the pump device 1 will be described with reference to FIG. 5 . FIG. 5 is a diagram showing a control procedure of the pump device 1 . A host controller 41 is provided outside the pump device 1 as an external command device. The pump device 1 and the host controller 41 are connected via communication signal transmission means or contacts. When the host controller 41 generates an activation command signal for the pump 2, the activation command signal is transmitted to the control device 5, and the pump 2 is activated. The host controller 41 is, for example, a control device that controls the operation of a semiconductor manufacturing device. An operation panel may be provided outside the pump device 1 as an external command device, and an operation command signal for starting the pump 2 may be transmitted from the operation panel to the control device 5 by an operator's operation.

When the control device 5 receives the start command signal of the pump 2 , the control device 5 issues a command to the inverter 4 to drive the motor 3 at a preset target rotational speed. Inverter 4 supplies electric power corresponding to the target rotational speed to motor 3 when receiving a command from control device 5 . The optimum value of the voltage applied to the motor 3 is determined by the specification of the coil 40 . For example, in the case of a permanent magnet type DC motor, the rotation speed of the motor 3 is approximately proportional to the supply voltage, so a voltage proportional to the rotation speed is applied to the motor 3 . The torque of the motor 3 is controlled by the magnitude of the current supplied to the motor 3 . The control device 5 controls the output power of the inverter 4 so that the motor 3 rotates at a target rotation speed. The rotation speed of the motor 3 may be detected by a rotation sensor not shown, or the current flowing through the motor 3 may be fed back to the control device 5, and the rotation speed of the motor 3 may be calculated from the current. Alternatively, the current flowing through the motor 3 may be fed back to the inverter 4, and the inverter 4 may calculate the rotational speed of the motor 3 from the current.

In the pump device 1 , a plurality of temperature sensors are installed in addition to the pump temperature sensor 14 . These temperature sensors will be described with reference to FIG. 6 . FIG. 6 is a diagram showing a location where a temperature sensor is arranged in the pump device 1 . The pump temperature sensor 14 is attached to the pump casing 20 to measure the pump casing 20 . The bearing temperature sensor 42 is arranged near the bearing 25 of the pump 2 and measures the temperature of the bearing 25 . The rotor temperature sensor 43 is arranged inside the pump 2 and measures the temperature of the pump rotor 21 . The motor temperature sensor 44 is attached to the coil 40 of the motor 3 to measure the temperature of the motor 3 . The intake air temperature sensor 45 is attached to the intake pipe 8 and measures the temperature of the air flowing into the pump 2 . The exhaust gas temperature sensor 46 is attached to the exhaust pipe 9 and measures the temperature of the gas discharged from the pump 2 . The temperatures detected by these temperature sensors are converted into temperature signals by the respective temperature sensors and sent to the control device 5 . Furthermore, the temperature signals obtained by the respective temperature sensors are sent from the control device 5 to the host controller 41 . When it is difficult to attach a temperature sensor to the coil 40 , the control device 5 may estimate the temperature of the coil 40 from the output current of the inverter 4 .

As a result of supplying a current exceeding the continuous rated current value to the motor 3, when the heat of the motor 3 and the inverter 4 exceeds the cooling capacity of the pump device 1 itself, the motor 3 and the inverter 4 will overheat. However, if the current value is lowered before the inverter 4 and the motor 3 overheat, a current larger than the continuous rated current value can temporarily flow. In this specification, the maximum current value that can flow temporarily is referred to as an instantaneous rated current value.

The control device 5 has a function of switching the limit value of the current output from the inverter 4 between a first current limit value and a second current limit value during driving of the motor 3 . The first current limit value is the above-mentioned continuous rated current value, and the second current limit value is the above-mentioned instantaneous rated current value. These first current limit values and second current limit values are stored in the control device 5 in advance. A specific switching will be described with reference to FIG. 7 .

FIG. 7 is a diagram showing switching between a first current limit value and a second current limit value. As shown in FIG. 7 , the control device 5 can switch between the first current limit value and the second current limit value. In order to prevent failure of the motor 3 and the inverter 4 , the first current limit value is set to the smaller of the continuous rated current value of the motor 3 and the continuous rated current value of the inverter 4 . Similarly, the second current limit value is set to the smaller of the instantaneous rated current value of the motor 3 and the instantaneous rated current value of the inverter 4 . In FIG. 7, since the continuous rated current value of the motor 3 is smaller than the continuous rated current value of the inverter 4, the continuous rated current value of the motor 3 is set to the first current limit value. Since the instantaneous rated current value of the motor 3 is smaller than the instantaneous rated current value of the inverter 4, the instantaneous rated current value of the motor 3 is set to the second current limit value.

The magnitude of the instantaneous rated current value is determined by the time of flowing current. Therefore, when the current flow time is short, a larger current can flow than when the current flow time is long. The second current limit value is set to several times to several tens of times the continuous rated current value.

The control device 5 preferably counts an accumulated value of the number of times of switching from the first current limit value to the second current limit value, and when the accumulated value exceeds a predetermined threshold value, the control device 5 reduces the second current limit value itself. Alternatively, the control device 5 may also count the frequency of switching from the first current limit value to the second current limit value, and when the frequency is higher than a predetermined threshold value, the control device 5 lowers the second current limit value itself. .

The conditions for switching between the first current limit value and the second current limit value will be described with reference to FIG. 8 . FIG. 8 is a diagram showing an example of operation control of the pump 2 . In FIG. 8 , the current limit value corresponding to the electric power of 15 kW is set as the first current limit value, and the current limit value corresponding to the electric power of 20 kW is set as the second current limit value. In the example shown in FIG. 8 , the pump temperature, the motor temperature, and the bearing temperature are measured by the pump temperature sensor 14 , the motor temperature sensor 44 , and the bearing temperature sensor 42 . The upper limit value of each temperature was set to 100°C. In addition, the operating conditions shown in FIG. 8 are not limited thereto, and the operating conditions may be set arbitrarily. For example, since the temperature detected by the temperature sensor varies depending on the location where it is installed, the upper limit of each temperature is not limited thereto. In addition, since both the first current limit value and the second current limit value vary depending on the inverter and the motor employed, they are not limited to the illustrated example.

In the case of continuously operating the pump 2 (condition 1), the output current limit value of the inverter 4 is set to the first current limit value. When the pump 2 is activated (condition 2), the control device 5 switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value. Thereby, the torque of the motor 3 increases, and the pump 2 can be rapidly increased to the rated speed. The control device 5 switches the output current limit value of the inverter 4 from the second current limit value to the first current limit value after a predetermined time (30 seconds in FIG. 8 ) has elapsed since the start of the pump 2 . Thereby, the pump 2 can be stably operated without malfunctioning of the pump 3 and the inverter 4 .

When the product enters the pump 2, the load on the motor 3 increases, and the operation of the pump 2 is hindered. In the case of removing the entering product (condition 3), the control device 5 switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value according to an instruction from the host controller 41 . When the temperature of the pump 2 exceeds the upper limit of 100° C. to 120° C., the control device 5 switches the output current limit value of the inverter 4 from the second current limit value to the first current limit value. When the temperature of the pump 2 becomes 100° C. or lower, the control device 5 switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value again according to an instruction from the host controller 41 .

When the atmospheric pressure gas in the vacuum chamber 11 is exhausted (condition 4), the control device 5 controls the inverter 4 under the same operating conditions as those shown in the condition 3. When the pump 2 is started, the control device 5 switches the output current limit value of the inverter 4 to the second current limit value in accordance with an instruction from the host controller 41 in order to prevent a decrease in the rotation speed of the pump 2 . When the temperature of the motor 3 reaches 120° C. and the motor temperature sensor 44 detects this, the control device 5 switches the output current limit value of the inverter 4 from the second current limit value to the first current limit value. When the temperature of the motor 3 becomes below 100° C., the control device 5 switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value again according to an instruction from the host controller 41 .

The above-mentioned switching from the first current limiting value to the second current limiting value is performed in accordance with an instruction from the host controller 41 , but the control device 5 may be made to determine switching of the output current limiting value of the inverter 4 . A specific determination of switching of the output current limit value will be described with reference to FIG. 9 . FIG. 9 is a diagram for explaining judgment of switching of an output current limit value. The horizontal axis shown in FIG. 9 represents the output current of the inverter 4 , and the vertical axis represents the rotational speed of the pump 2 . When the load on the pump 2 is sufficiently small, the inverter 4 outputs a current smaller than the first limit current value to operate the pump 2 at a rated speed ( P1 ). The control device 5 adjusts the output current of the inverter 4 according to the load of the pump 2 so that the rotation speed of the pump 2 is constant. When the load on the pump 2 increases, the inverter 4 outputs a current corresponding to the first current limit value to operate the pump 2 at a rated speed ( P2 ).

When the load of the pump 2 further increases, the rotation speed of the pump 2 decreases (P3). When the inverter 4 outputs a current equivalent to the first current limit value, if the control device 5 detects a decrease in the rotational speed of the pump 2, the control device 5 changes the output current limit value of the inverter 4 from the first current limit value to Switch to the 2nd current limit value. As a result, the output current of the inverter 4 rises to the second current limit value ( P4 ). The inverter 4 supplies a current corresponding to the second current limit value to the motor 3 , thereby increasing the torque of the motor 3 and returning the rotation speed of the pump 2 to the rated speed ( P5 ). When the load decreases, the control device 5 switches the output current limit value of the inverter 4 from the second current limit value to the first limit current value ( P2 ). When the load is still heavy, the motor 3 is driven with electric power corresponding to the second current limit value. In order to prevent overheating of the motor 3 and the inverter 4, when the operating time of the motor 3 at the second current limit value exceeds a predetermined time, the control device 5 changes the output current limit value of the inverter 4 from the second current limit value to the second current limit value. The limit value is switched to the first current limit value.

During the standby operation of the pump 2 , the control device 5 controls the inverter 4 so that the rotation speed of the motor 3 is reduced to the necessary minimum rotation speed ( P6 ). The pump 2 immediately returns to the rated speed by a signal from the host controller 41 or an operation of the operation panel.

In order to prevent failures due to overheating of the pump unit, the control device 5 has a failure avoidance function. For example, when the temperature measured by at least one of the temperature sensors 14, 42, 43, 44, 45, and 46 exceeds a predetermined threshold value, the failure avoidance function of the control device 5 works, and the inverter The output current limit value of 4 is switched from the second current limit value to the first current limit value. When the temperature detected by the temperature sensor exceeds a predetermined threshold value, the control device 5 may lower the second current limit value itself.

In the above example, when the output time of the current corresponding to the second current limit value exceeds the predetermined time, the control device 5 switches from the second current limit value to the first current limit value. Alternatively, the control device 5 may switch the output current limit value of the inverter 4 from the second current limit value to the first current limit value in accordance with the flow rate of gas detected by the flow sensor 13 . For example, in the case of discharging a large amount of gas, the control device 5 receives a signal from the host controller 41 or the operation panel, and switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value. When the flow rate measured by the flow sensor 13 falls to a predetermined value, the output current limit value of the inverter 4 is switched from the second current limit value to the first current limit value.

When the output current of the inverter 4 is large although the flow rate measured by the flow rate sensor 13 is low, it is considered that a product is attached to the pump rotor 21 . Therefore, in such a case, it is preferable to remove the product by switching the output current limit value of the inverter 4 from the first current limit value to the second current limit value. Specifically, when the flow rate measured by the flow sensor 13 is equal to or less than a predetermined threshold and the output current of the inverter 4 is greater than or equal to the predetermined threshold, it is preferable that the control device 5 adjusts the output current of the inverter 4 to The limit value is switched from the first current limit value to the second current limit value. When the flow rate measured by the flow sensor 13 is large and the output current of the inverter 4 is also large, this is considered to be a normal operating state, so the output current limit value of the inverter 4 is maintained at the first current limit value.

Also, when the integrated value of the output power of the inverter 4 exceeds a predetermined threshold, the control device 5 may switch the output current limit value of the inverter 4 from the second current limit value to the first current limit value. Specifically, the control device 5 may store the output power of the inverter 4 every predetermined unit time (for example, 0.1 second), and calculate the cumulative value of the output power per the predetermined unit time for a predetermined period (for example, several seconds). , when the integrated value exceeds a predetermined threshold value, the output current limit value of the inverter 4 is switched from the second current limit value to the first current limit value.

When the switching from the first current limit value to the second current limit value occurs frequently, it is considered that there is a high risk that the pump 2 will stop due to external factors such as entry of foreign matter. Therefore, the control device 5 preferably issues a warning when the frequency of switching from the first current limit value to the second current limit value exceeds a predetermined threshold value. In addition, it is preferable to notify the host controller 41 or the operation panel of the warning by means of a communication signal transmission unit or a contact.

As described above, the control device 5 temporarily increases the output current limit value of the inverter 4, whereby the pump unit can be operated stably while preventing overheating of the pump unit.

(a) of FIG. 10 is a graph showing the relationship between the output power of the inverter 4 and the rotational speed of the motor 3 when the output current limit value of the inverter 4 is set to the first current limit value. 10(b) is a graph showing the relationship between the output current of the inverter 4 and the rotation speed of the motor 3, and FIG. 10(c) is a graph showing the relationship between the output voltage of the inverter 4 and the rotation speed of the motor 3. . In (a) of FIG. 10 , when the motor 3 is started, the rotation speed of the motor 3 rises to a rated speed. The inverter 4 outputs electric power so that the rotation speed of the motor 3 is kept constant. When the load applied to the pump 2 increases, the output current of the inverter 4 reaches the first current limit value as shown in FIG. 10( b ). When the load applied to the pump 2 further increases and the load torque becomes larger than the rotation torque of the motor 3, the rotation speed of the motor 3 decreases while the output current value of the inverter 4 is maintained at the first current limit value. When the rotational speed of the motor 3 decreases, as shown in FIG. 10( c ), the output voltage of the inverter 4 decreases, and accordingly, as shown in FIG. 10( a ), the output power of the inverter 4 decreases.

(a) of FIG. 11 is a graph showing the relationship between the output power of the inverter 4 and the rotational speed of the motor 3 when the output current limit value of the inverter 4 is set to the second current limit value. 11( b ) is a graph showing the relationship between the output current of the inverter 4 and the rotation speed of the motor 3 , and FIG. 11( c ) is a graph showing the relationship between the output voltage of the inverter 4 and the rotation speed of the motor 3 . The dashed line shown in (a) of FIG. 11 is the same as the graph shown in (a) of FIG. 10 , and the dashed line shown in (b) of FIG. 11 is the same as the graph shown in (b) of FIG. 10 . The electric power of the inverter 4 is controlled so that the rotational speed of the motor 3 is maintained at a rated speed. When the load on the pump 2 increases, as shown in FIG. 11( b ), the output power of the inverter 4 reaches the second current limit value. When the load applied to the pump 2 increases further and the load torque becomes larger than the rotation torque of the motor 3, the rotation speed of the motor 3 decreases while the output current value of the inverter 4 is maintained at the second current limit value. When the rotation speed of the motor 3 decreases, as shown in FIG. 11( c ), the output voltage of the inverter 4 decreases, and accordingly, as shown in FIG. 11( a ), the output power of the inverter 4 decreases.

As shown in (a) of FIG. 11 , when the motor 3 is driven by setting the output current limit value of the inverter 4 to the second current limit value, the motor 3 is driven as shown in (a) of FIG. 10 . In comparison, the electric power increases by an amount corresponding to the length L. Therefore, the torque of the motor 3 increases, and the rotation speed is difficult to decrease even if the load increases.

Fig. 12 is a diagram showing another example of a vacuum evacuation system including a dry vacuum pump device. This vacuum evacuation system has a pump device 1 , a load-lock vacuum chamber 50 connected to the pump device 1 , and a vacuum chamber 11 connected to the load-lock vacuum chamber 50 . A load lock vacuum chamber 50 is arranged between the vacuum chamber 11 and the pump device 1 . The load lock vacuum chamber 50 and the vacuum chamber 11 are connected through a communication pipe 51 , and a gate valve 52 capable of opening and closing is installed on the communication pipe 51 . By closing the gate valve 52 , the gas communication between the vacuum chamber 11 and the load lock vacuum chamber 50 is cut off. The load lock chamber 50 is a device used in, for example, a semiconductor manufacturing device, and enables a substrate to be taken in and out of the vacuum chamber 11 while maintaining a vacuum state in the vacuum chamber 11 .

Vacuum is always maintained in the vacuum chamber 11 . A wafer is placed in the load lock chamber 50 , and the inside of the load lock chamber 50 is evacuated by the pump 2 . After the inside of the load lock chamber 50 is vacuumed, the gate valve 52 is opened to carry the wafer from the load lock chamber 50 into the vacuum chamber 11 . After the wafer is processed in the vacuum chamber 11, the wafer is moved from the vacuum chamber 11 to the load lock vacuum chamber 50, and after the gate valve 52 is closed, the air pressure in the load lock vacuum chamber 50 is returned to atmospheric pressure, and the wafer is removed from the vacuum chamber 11. The load lock chamber 50 is removed.

The evacuation of the load lock chamber 50 is performed as follows. The pump 2 is operated at a rated speed, and in this state, the suction valve 53 between the load-lock vacuum chamber 50 and the pump 2 is opened. Then, the gas at the atmospheric pressure in the load lock chamber 50 is sucked into the pump 2 at one go, and the inside of the load lock chamber 50 is evacuated from the atmospheric pressure to a vacuum. In this evacuation process, when the suction valve 53 is opened, the gas in the load lock chamber 50 flows into the pump 2 in one go, and thus an excessive load is applied to the pump 2 . Therefore, the rotation speed of the motor 3 may decrease, and the discharge speed of the pump 2 may decrease.

In order to solve this problem, in the present embodiment, the motor 3 is driven under the condition that the output current limit value of the inverter 4 is set to the second current limit value before a predetermined time elapses after the suction valve 53 is opened. When the suction valve 53 is opened, the control device 5 switches the output current limit value of the inverter 4 from the first current limit value to the second current limit value. After the suction valve 53 is opened, the rotational speed of the pump 2 can be several percent to more than ten percent higher than the rated speed within a preset time. The discharge speed of the pump 2 can be increased by increasing the rotation speed of the pump 2 . Thereby, the exhaust time in the load-lock vacuum chamber 50 can be shortened, and productivity can be improved.

FIG. 13 is a schematic diagram of a dry vacuum pump device 90 according to a second embodiment of the present invention. Components that are the same as or corresponding to those of the first embodiment are given the same reference numerals, and overlapping descriptions are omitted. As shown in FIG. 13 , a dry vacuum pump device 90 includes a booster pump unit 92 connected to the vacuum chamber 11 via a connecting pipe 12 and a main pump unit 93 connected to the booster pump unit 92 . The boost pump unit 92 has a boost pump 102 , a motor 103 and an inverter 104 . The main pump unit 93 has a main pump 106 , a motor 107 and an inverter 108 . The main pump 106 is a pump that discharges the gas in the vacuum chamber 11 from the atmospheric pressure, and the booster pump 102 is a pump that further discharges the gas in the vacuum chamber 11 to increase the degree of vacuum. The booster pump 102 may be activated after the main pump 106 is activated, or the pumps 102, 106 may be activated simultaneously.

The main pump 106 in this embodiment has the same structure as the pump 2 shown in FIG. 2 . The intake pipe 111 of the main pump 106 is connected to the exhaust port of the booster pump 102 . The booster pump 102 has a smaller number of pump rotors than the main pump 106 . The booster pump 102 has a higher exhaust velocity than the main pump 106 .

The booster pump 102 is connected to a motor 103 , and the motor 103 is connected to an inverter 104 . The main pump 106 is connected to a motor 107 , and the motor 107 is connected to an inverter 108 . A control device 110 for controlling the operations of the inverter 104 and the inverter 108 is disposed near the inverter 104 and the inverter 108 . The control device 110 is connected to an operation panel (external command device) 115 provided outside the pump device 90, and the operator operates the operation panel 115 to switch between the first current limit value and the second current limit value. The command signal of the output current limit value of the inverter 104 and/or the inverter 108 is sent to the control device 110 . The configuration and operation of the control device 110 that are not particularly described are the same as those of the above-mentioned control device 5, and thus redundant description thereof will be omitted.

A plurality of temperature sensors for measuring the temperature in these pump units 92 and 93 are attached to the booster pump unit 92 and the main pump unit 93 . Although not shown, the same temperature sensor as that of the booster pump unit 92 is attached to the main pump unit 93 . Hereinafter, the temperature sensor attached to the booster pump unit 92 will be described, and the redundant description of the temperature sensor will be omitted.

The pump temperature sensor 120 is attached to the pump housing 121 of the booster pump 102 to measure the temperature of the pump housing 121 . The bearing temperature sensor 122 is arranged near the bearing 123 of the booster pump 102 and measures the temperature of the bearing 123 . The rotor temperature sensor 124 is disposed inside the booster pump 102 and measures the temperature of a pump rotor (not shown). The motor temperature sensor 125 is attached to the coil 126 of the motor 103 to measure the temperature of the motor 103 . The intake air temperature sensor 127 is attached to the intake pipe 130 of the booster pump 102 and measures the temperature of the gas flowing into the booster pump 102 . The exhaust gas temperature sensor 128 is attached to the exhaust pipe 131 of the main pump 106 to measure the temperature of the gas discharged from the main pump 106 .

In order to prevent failures due to overheating of the pump unit, the control device 110 has a failure avoidance function. For example, when the temperature detected by at least one of the temperature sensors installed in the booster pump unit 92 and the main pump unit 93 exceeds a predetermined threshold value, the failure avoidance function of the control device 110 works, and the inverter The output current limit value of the inverter 104 or the inverter 108 is switched from the second current limit value to the first current limit value. When the temperature detected by the temperature sensor exceeds a predetermined threshold, the control device 110 may lower the second current limit value itself.

FIG. 14 is a schematic diagram showing a state where a host controller 41 is connected to the control device 110 as an external command device instead of the operation panel 115 . The control device 110 switches the output current limit value of the inverter 104 and/or the inverter 108 from the first current limit value to the second current limit value based on the switch command signal sent from the host controller 41 .

FIG. 15 is a diagram schematically showing a system of the pump device 90 shown in FIGS. 13 and 14 . The temperature sensors shown in FIG. 15 collectively represent temperature sensors 120 , 122 , 124 , 125 , 127 , and 128 . As shown in FIG. 15 , the temperature sensors installed in the booster pump unit 92 and the main pump unit 93 are connected to the control device 110 via a communication signal transmission unit or contacts. The temperature signals obtained by the respective temperature sensors are sent from the control device 110 to the host controller 41 or the operation panel 115 . The control device 110 is also connected to the inverter 104 and the inverter 108 , and controls the operations of the inverter 104 and the inverter 108 based on signals from the operation panel 115 or the host controller 41 .

FIG. 16 is a diagram showing an example of operation control of the booster pump 102 and the main pump 106 . In FIG. 16 , the current limit value corresponding to the power of 15 kW is set as the first current limit value, the current limit value corresponding to the power of 20 kW is set as the second current limit value, and the current limit value corresponding to the power of 10 kW is The value is set to the third current limit value. As shown in FIG. 16 , when the total power supplied to the pump device 90 is set to 30 kW and the pump device 90 is normally operated (condition 1), the output current limit values of the inverters 104 and 108 are set to 1st current limit value. Therefore, a maximum of 15 kW of electric power is supplied to each of the booster pump unit 92 and the main pump unit 93 .

The case of starting the pump device 90 (condition 2) will be described. When the pump device 90 is started and the main pump 106 is given priority to operate, the output current limit value of the inverter 108 is switched to the second current limit value, and the output current limit value of the inverter 104 is set to be lower than the second current limit value. 1. The 3rd current limit value which is lower than the current limit value. Therefore, the inverter 108 supplies a maximum of 20 kW of electric power to the motor 107 , and the inverter 104 supplies a maximum of 10 kW of electric power to the motor 103 . Next, the booster pump 102 is operated with priority. In this case, the output current limit value of the inverter 108 is switched to the third current limit value, and the output current limit value of the inverter 104 is switched to the second current limit value. Therefore, the inverter 104 supplies a maximum of 20 kW of electric power to the motor 103 , and the inverter 108 supplies a maximum of 10 kW of electric power to the motor 107 . Then, the pump device 90 operates in the normal operation mode. In this normal operation, the output current limit values of the inverters 104 and 108 are switched to the first current limit value. Therefore, the inverters 104, 108 supply the motors 103, 107 with a maximum of 15 kW of electric power each.

In the case of removing the product (condition 3), the booster pump priority operation is performed. That is, the output current limit value of the inverter 104 is switched to the second current limit value, and the output current limit value of the inverter 108 is switched to the third current limit value. Therefore, the inverter 104 supplies a maximum of 20 kW of electric power to the motor 103 , and the inverter 108 supplies a maximum of 10 kW of electric power to the motor 107 . Since the inverter 104 supplies a maximum of 20 kW of electric power to the motor 103, the torque of the motor 103 increases and the product is removed.

In the case of exhausting the gas in the vacuum chamber 11 from the atmospheric pressure (condition 4), the main pump priority operation is performed first. That is, the output current limit value of the inverter 108 is switched to the second current limit value, and the output current limit value of the inverter 104 is switched to the third current limit value. Therefore, the inverter 108 supplies a maximum of 20 kW of electric power to the motor 107 , and the inverter 104 supplies a maximum of 10 kW of electric power to the motor 103 . After the gas in the vacuum chamber 11 is exhausted to a certain extent, the priority operation of the booster pump is performed next. That is, the output current limit value of the inverter 104 is switched to the second current limit value, and the output current limit value of the inverter 108 is switched to the third current limit value. Therefore, the inverter 104 supplies a maximum of 20 kW of electric power to the motor 103 , and the inverter 108 supplies a maximum of 10 kW of electric power to the motor 107 . By operating the booster pump 102 and the main pump 106 under such operating conditions, the gas in the vacuum chamber 11 can be discharged at high speed. As a result, the time until the target vacuum is formed can be shortened. In addition, the operating conditions shown in FIG. 16 are not limited thereto, and the operating conditions may be set arbitrarily.

(a) of FIG. 17 is a graph showing the relationship between the output power of the inverter 108 of the main pump unit 93 and the rotational speed of the motor 107 during the priority operation of the booster pump, and (b) of FIG. 17( c ) is a graph showing the relationship between the output voltage of the inverter 108 and the rotational speed of the motor 107 . The dotted line in (a) of FIG. 17 shows the relationship between the rotational speed of the motor 107 and the output power of the inverter 108 when the output current limit value of the inverter 108 is set to the first current limit value. The (a) of FIG. 17 ) represents the relationship between the rotation speed of the motor 107 and the output power of the inverter 108 when the output current limit value of the inverter 108 is set to the third current limit value.

When the motor 107 is started, the rotational speed of the motor 107 rises to the rated speed. The inverter 108 outputs electric power so that the rotation speed of the motor 107 is kept constant. When the load applied to the main pump 106 increases, as shown in FIG. 17( b ), the output current of the inverter 108 reaches the third current limit value. When the load applied to the main pump 106 further increases, the rotation speed of the motor 107 decreases while the output current of the inverter 108 is maintained at the third current limit value. When the rotational speed of the motor 107 decreases, as shown in (c) of FIG. 17 , the output voltage of the inverter 108 decreases, and accordingly, as shown in (a) of FIG. 17 , the output power of the inverter 108 decreases.

When the booster pump 102 is operated with priority, since the electric power supplied to the motor 107 is smaller than the electric power corresponding to the first current limit value, as shown by the solid lines in (a) and (b) of FIG. As shown, a current smaller than that during normal operation is supplied to the motor 107.

(a) of FIG. 18 is a graph showing the relationship between the output power of the inverter 104 of the boost pump unit 92 and the rotation speed of the motor 103 when the boost pump is preferentially operated, and (b) of FIG. 18 (c) is a graph showing the output voltage of the inverter 104 and the rotation speed of the motor 103 during the priority operation of the booster pump. Relationship graph.

The dotted line in (a) of FIG. 18 shows the relationship between the rotation speed of the motor 103 and the output power of the inverter 104 when the output current limit value of the inverter 104 is set to the first current limit value. The (a) of FIG. 18 ) represents the relationship between the rotation speed of the motor 103 and the output power of the inverter 104 when the output current limit value of the inverter 104 is set to the second current limit value. As shown in (a) of FIG. 18 , the power value when the output current limit value of the inverter 104 is switched from the first current limit value to the second current limit value increases by an amount corresponding to the length L. As a result, the torque of the motor 103 increases, and the rotational speed of the booster pump 102 remains constant even when the load increases. The graphs shown in (a) to (c) of FIG. 18 are the same as the graphs shown in (a) to (c) of FIG. 11 .

The embodiments of the present invention have been described so far, but the present invention is not limited to the above-described embodiments, and can of course be implemented in various forms within the scope of its technical concept.

Claims (7)

1. a kind of dry vacuum pump apparatus, there is at least one pump unit and control the control device of the pump unit and survey At least one temperature sensor of the temperature of the fixed pump unit, it is characterised in that

The pump unit has：

Dry vacuum pump；

Drive the motor of the dry vacuum pump；With

The inverter of the rotating speed of the motor is controlled,

The control device has switches to the 2nd electric current by the output current limits value of the inverter from the 1st current limit value The function of limits value, the 1st current limit value are the maximums for the electric current that the inverter can continuously flow to the motor That is continuous rating current value, the 2nd current limit value are the values more than the continuous rating current value,

The control device by the temperature of the temperature sensor measurement when exceeding predetermined threshold value, by the inverter Output current limits value switch to the 1st current limit value from the 2nd current limit value.

2. dry vacuum pump apparatus according to claim 1, it is characterised in that

The control device is true in the dry type when the inverter exports the electric current suitable with the 1st current limit value It is in the case that the rotating speed of empty pump is less than predetermined rotating speed of target, the output current limits value of the inverter is electric from the described 1st Stream limits value switches to the 2nd current limit value.

3. dry vacuum pump apparatus according to claim 2, it is characterised in that

The control device is when the rotating speed for detecting the pump reverts to the rotating speed of target, by the output electricity of the inverter Stream limits value switches to the 1st current limit value from the 2nd current limit value.

4. dry vacuum pump apparatus according to claim 2, it is characterised in that

The control device has exceeded the feelings of predetermined threshold value in the output time of the electric current suitable with the 2nd current limit value Under condition, the output current limits value of the inverter is switched into the 1st current limit value from the 2nd current limit value.

5. dry vacuum pump apparatus according to claim 1, it is characterised in that

At least one temperature sensor is selected from the temperature sensor of the temperature for the pump case for determining the dry vacuum pump, surveyed The temperature sensor of the temperature of the bearing of the fixed dry vacuum pump, the temperature sensor of the temperature of the measure motor, measure The temperature sensor of the temperature of the pump rotor of the dry vacuum pump, the measure dry vacuum pump suction gas temperature The temperature sensor of the temperature of the discharge gas of temperature sensor and the measure dry vacuum pump.

6. dry vacuum pump apparatus according to claim 1, it is characterised in that

The control device is according to the instruction from the external command device being arranged at outside the dry vacuum pump apparatus, by institute The output current limits value for stating inverter switches to the 2nd current limit value from the 1st current limit value.

7. according to dry vacuum pump apparatus according to any one of claims 1 to 6, it is characterised in that

At least one pump unit is by the main pump unit of the gas discharge of atmospheric pressure and the increasing for discharging the gas of vacuum pressure Pump unit,

Electric power to make to be supplied to the dry vacuum pump apparatus operated in a manner of being no more than value set in advance the main pump and The booster pump.